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Bibliography on: Invasive Species

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ESP: PubMed Auto Bibliography 12 Nov 2018 at 01:35 Created: 

Invasive Species

Standard Definition: Invasive species are plants, animals, or pathogens that are non-native (or alien) to the ecosystem under consideration and whose introduction causes or is likely to cause harm. Although that definition allows a logical possibility that some species might be non-native and harmless, most of time it seems that invasive species and really bad critter (or weed) that should be eradicated are seen as equivalent phrases. But, there is a big conceptual problem with that notion: every species in every ecosystem started out in that ecosystem as an invader. If there were no invasive species, all of Hawaii would be nothing but bare volcanic rock. Without an invasion of species onto land, there would be no terrestrial ecosystems at all. For the entire history of life on Earth, the biosphere has responded to perturbation and to opportunity with evolutionary innovation and with physical movement. While one may raise economic or aesthetic arguments against invasive species, it is impossible to make such an argument on scientific grounds. Species movement — the occurrence of invasive species — is the way the biosphere responds to perturbation. One might even argue that species movement is the primary, short-term "healing" mechanism employed by the biosphere to respond to perturbation — to "damage." As with any healing process, the short-term effect may be aesthetically unappealing (who thinks scabs are appealing?), but the long-term effects can be glorious.

Created with PubMed® Query: "invasive species" OR "invasion biology" OR "alien species" OR "introduced species" NOT pmcbook NOT ispreviousversion

Citations The Papers (from PubMed®)

RevDate: 2018-11-11

Norbury G, W van Overmeire (2018)

Low structural complexity of non-native grassland habitat exposes prey to higher predation.

Ecological applications : a publication of the Ecological Society of America [Epub ahead of print].

The structural complexity of vegetation can have profound effects on the hunting efficiency of predators, thereby affecting their intake rate of prey. While studies have shown that vegetation complexity can play an important role in managing unwanted impacts of predators, it is less clear how structural complexity of invasive vegetation affects the vulnerability of terrestrial prey. Short non-native pasture species, for example, bred for agricultural production are highly invasive and pervade grassland ecosystems worldwide. They generally have low structural complexity compared with taller native vegetation they often displace. We conducted controlled experiments to test whether non-native pastures expose fauna to greater predation risk. Survival of invertebrates (tethered locusts) subject to predation by invasive mammalian insectivores (European hedgehogs) in non-native pasture (0.10 per 24 hrs; 95% CI, 0.08-0.13) was less than half that in structurally complex native perennial tussock (bunch) grass (0.24; 95% binomial CI, 0.18-0.31). A significant positive relationship was apparent between structural complexity (grass dry stem density) surrounding each locust and their survival. In a second experiment, survival of locusts placed solely in tussock increased with decreasing locust density in tussock, presumably reflecting fewer resource-rich patches that predators could focus on. These results demonstrate that invasion by structurally simple non-native vegetation exposes prey to greater risk of predation. This is concerning from a global nature conservation perspective given that conversion of nearly half of the world's temperate grasslands to agriculture includes a range of invasive, structurally simple non-native plant species. Minimising invasion, and maintaining and restoring complex habitat structure may be a useful conservation option for reducing unwanted predation. This article is protected by copyright. All rights reserved.

RevDate: 2018-11-10

Balestri E, Vallerini F, Menicagli V, et al (2018)

Biotic resistance and vegetative propagule pressure co-regulate the invasion success of a marine clonal macrophyte.

Scientific reports, 8(1):16621 pii:10.1038/s41598-018-35015-0.

Propagule pressure is considered a major driver of plant invasion success. Great propagule pressure would enable invasive species to colonize new areas overcoming the resistance of native species. Many highly invasive aquatic macrophytes regenerate from vegetative propagules, but few studies have experimentally investigated the importance of propagule pressure and biotic resistance, and their interaction, in determining invasion success. By manipulating both recipient habitat and the input of vegetative propagules of the invasive seaweed Caulerpa cylindracea in mesocosm, we examined whether higher propagule pressure would overcome the resistance of a native congeneric (Caulerpa prolifera) and influence its performance. With the native, C. cylindracea population frond number decreased irrespectively of pressure level. High propagule pressure did not increase stolon length and single plant size decreased due to the effects of intra- and interspecific competition. Native biomass decreased with increasing C. cylindracea propagule pressure. These results indicate that higher propagule pressure may fail in enhancing C. cylindracea invasion success in habitats colonized by the native species, and they suggest that biotic resistance and propagule pressure co-regulate the invasion process. These findings emphasize the need to preserve/restore native seaweed populations and may help to design effective management actions to prevent further C. cylindracea spread.

RevDate: 2018-11-09

Gao GF, Li PF, Zhong JX, et al (2018)

Spartina alterniflora invasion alters soil bacterial communities and enhances soil N2O emissions by stimulating soil denitrification in mangrove wetland.

The Science of the total environment, 653:231-240 pii:S0048-9697(18)34174-3 [Epub ahead of print].

Chinese mangrove, an important ecosystem in coastal wetlands, is sensitive to the invasive alien species Spartina alterniflora. However, the effects of the S. alterniflora invasion on mangrove soil N2O emissions and the underlying mechanisms by which emissions are affected have not been well studied. In this study, the N2O emitted from soils dominated by two typical native mangroves (i.e. Kandelia obovata: KO; Avicennia marina: AM), one invaded by S. alterniflora (SA), and one bare mudflat (Mud) were monitored at Zhangjiang Mangrove Estuary (where S. alterniflora is exotic). Together with soil biogeochemical properties, the potential denitrification rate and the composition of soil bacterial communities were determined simultaneously by 15NO3- tracer and high-throughput sequencing techniques, respectively. Our results showed that S. alterniflora invasion significantly (p < 0.05) increases soil N2O emissions by 15-28-fold. In addition, isotope results revealed that the soil potential denitrification rate was significantly (p < 0.05) enhanced after S. alterniflora invasion. Moreover, the S. alterniflora invasion significantly (p < 0.05) decreased soil bacterial α-diversity and strongly modified soil bacterial communities. Indicator groups strongly associated with S. alterniflora were Chloroflexia, Alphaproteobacteria, and Bacilli, each of which was abundant and acts as connector in the co-occurrence network. FAPROTAX analysis implied that the S. alterniflora invasion stimulated soil denitrification and nitrification while depressing anaerobic ammonium oxidation (anammox) and dissimilatory nitrate reduction to ammonium (DNRA). Redundancy analysis (RDA) found that soil organic matter (SOM) and pH were the most important environmental factors in altering soil bacterial communities. Taken together, our results imply that the S. alterniflora invasion in mangrove wetlands significantly stimulates soil denitrification and N2O emissions, thereby contributing N2O to the atmosphere and contributing to global climate change.

RevDate: 2018-11-09

Dror H, Novak L, Evans JS, et al (2018)

Core and Dynamic Microbial Communities of Two Invasive Ascidians: Can Host-Symbiont Dynamics Plasticity Affect Invasion Capacity?.

Microbial ecology pii:10.1007/s00248-018-1276-z [Epub ahead of print].

Ascidians (Chordata, Ascidiacea) are considered to be prominent marine invaders, able to tolerate highly polluted environments and fluctuations in salinity and temperature. Here, we examined the seasonal and spatial dynamics of the microbial communities in the inner-tunic of two invasive ascidians, Styela plicata (Lesueur 1823) and Herdmania momus (Savigny 1816), in order to investigate the changes that occur in the microbiome of non-indigenous ascidians in different environments. Microbial communities were characterized using next-generation sequencing of partial (V4) 16S rRNA gene sequences. A clear differentiation between the ascidian-associated microbiome and bacterioplankton was observed, and two distinct sets of operational taxonomic units (OTUs), one core and the other dynamic, were recovered from both species. The relative abundance of the dynamic OTUs in H. momus was higher than in S. plicata, for which core OTU structure was maintained independently of location. Ten and seventeen core OTUs were identified in S. plicata and H. momus, respectively, including taxa with reported capabilities of carbon fixing, ammonia oxidization, denitrification, and heavy-metal processing. The ascidian-sourced dynamic OTUs clustered in response to site and season but significantly differed from the bacterioplankton community structure. These findings suggest that the associations between invasive ascidians and their symbionts may enhance host functionality while maintaining host adaptability to changing environmental conditions.

RevDate: 2018-11-09
CmpDate: 2018-11-09

Budzyńska A, Rosińska J, Pełechata A, et al (2019)

Environmental factors driving the occurrence of the invasive cyanobacterium Sphaerospermopsis aphanizomenoides (Nostocales) in temperate lakes.

The Science of the total environment, 650(Pt 1):1338-1347.

Cyanobacterial blooms are an increasing threat worldwide. Invasions of certain cyanobacterial species, mainly towards higher latitudes, add to this concern as they enrich the pool of potential bloom-formers in the invaded region. Among the numerous causes of this escalating process, climate warming is commonly considered the most crucial factor, but empirical studies of this issue are lacking. The aim of our study was to identify physical, chemical and biological factors related to the occurrence of an invasive cyanobacterium at the northern border of its putative current range, and thus enabling its expansion. This study focuses on the relatively little studied species Sphaerospermopsis aphanizomenoides (Nostocales, Cyanobacteria; synonyms: Aphanizomenon aphanizomenoides, Anabaena aphanizomenoides), which is predicted to become one of the main nuisance species of the future. Forty-nine freshwater lakes located between latitudes 51° and 55°N were examined for the presence of S. aphanizomenoides, and environmental factors that could drive its occurrence were studied simultaneously. To identify factors correlated with the presence of the species, principal component analysis (PCA) and Mann-Whitney U test were performed. Water temperature did not differentiate lakes with or without S. aphanizomenoides, however the study was conducted in a particularly hot summer. Total phosphorus concentration was identified as the primary driving factor of the occurrence of S. aphanizomenoides. The species grew in poor light conditions and high phytoplankton biomass, mainly in shallow lakes. As shown by detrended correspondence analysis (DCA), the species accompanied shade tolerant, eutrophic species of native and invasive cyanobacteria as well as eukaryotic algae. Our results indicate that eutrophication may be the primary factor enabling the increasing occurrence of S. aphanizomenoides in temperate environments, and suggest that this process may stimulate expansion of cyanobacterial species towards high latitudes.

RevDate: 2018-11-08

Turnipseed RK, Moran PJ, SA Allan (2018)

Behavioral responses of gravid Culex quinquefasciatus, Aedes aegypti, and Anopheles quadrimaculatus mosquitoes to aquatic macrophyte volatiles.

Journal of vector ecology : journal of the Society for Vector Ecology, 43(2):252-260.

Mosquitoes use many cues to assess whether a habitat is conducive for reproduction, possibly including the presence of stimuli from aquatic macrophytes. The effect of water infusions of water hyacinth (Eichhornia crassipes), water lettuce (Pista stratioles), parrotfeather (Myriophyllum aquaticum), and water pennywort (Hydrocotyle umbellata) on mosquito oviposition and attraction was investigated. Gravid Culex quinquefasciatus deposited significantly more egg rafts in water hyacinth, water lettuce, or Bermuda hay (positive control) infusions compared to water, while water pennywort and parrotfeather infusions did not differ from water. In-flight attraction responses of Cx. quinquefasciatus, Aedes aegypti, and Anopheles quadrimaculatus were evaluated. The strongest attraction of gravid Cx. quinquefasciatus and Ae. aegypti occurred in the presence of volatiles from infusions of water hyacinth and water lettuce, which were equal in attractiveness to hay infusion. Water pennywort and parrotfeather infusions were not attractive. Gravid An. quadrimaculatus were not attracted to aquatic plant volatiles. The results suggest that water hyacinth and water lettuce emit volatile chemicals that attract two of three mosquito species tested and stimulate oviposition by Cx. quinquefasciatus, demonstrating that the level of attraction of aquatic plant volatiles varies among species in ways that may have relevance to bait-based detection and control methods.

RevDate: 2018-11-08

Sammet K, Ivask M, O Kurina (2018)

A synopsis of Estonian myriapod fauna (Myriapoda: Chilopoda, Diplopoda, Symphyla and Pauropoda).

ZooKeys.

The data on Estonian Myriapoda are scattered in various publications and there has been no overview of the fauna up to the present. A critical summary of the previous information on Estonian Myriapoda is given, supplemented by new records and distribution maps. Altogether, 5784 specimens from 276 collecting sites were studied. To the hitherto recorded 14 centipede species are added Lithobiusmelanops, L.microps, Geophiluscarpophagus, G.flavus, Strigamiatranssilvanica and Stenotaenialinearis, a probably introduced species. Of the 27 published Estonian millipede species, the data on two species proved erroneous, and two new species were recorded (Craspedosomaraulinsii and Cylindroiulusbritannicus). Two previously recorded millipede species - Brachyiuluspusillus and Mastigophorophyllonsaxonicum - were not found in the recent samples, the latter may have become more rare or extinct. Pauropoda and Symphyla lack previous reliable records. Combined with published data, the number of myriapod species known from Estonia is now set at 52. Some changes in species distribution and frequencies were detected comparing the published data with new records. Some data about habitat preferences of the more common species are also given. The majority of species have a western Palaearctic distribution, while six species are at the northern limit of their ranges.

RevDate: 2018-11-08
CmpDate: 2018-11-08

Neven LG, Kumar S, Yee WL, et al (2018)

Current and Future Potential Risk of Establishment of Grapholita molesta (Lepidoptera: Tortricidae) in Washington State.

Environmental entomology, 47(2):448-456.

The oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae), is a primary pest of stone fruits that cause significant economic damage. Larvae, which enter the host plant through shoot tips, damage shoots, and ripe fruits. Native to Asia, this pest now occurs in many fruit-growing countries, including the United States and Canada. Though the pest was previously reported from many states within the United States, its current distribution and the environmental variables that influence its distribution are not properly identified. The objectives of this study were to 1) identify the environmental factors associated with G. molesta current distribution, 2) predict the current distribution of G. molesta in Washington State (WA) using Maxent and Climex models, 3) identify those areas within WA best suited for establishment of pest free zones, areas of low pest prevalence, and pest free production areas, and 4) identify regions most at risk for further expansion of G. molesta populations as a function of climate change. The current models predicted a small portion of central WA is suitable to support G. molesta, which is consistent with observed distributions. However, climate change models predict that more areas will become suitable for the pest. These results indicate that action should be taken to monitor and reduce current populations of G. molesta to stem its potential expansion into the major commercial tree fruit production areas in the state.

RevDate: 2018-11-08
CmpDate: 2018-11-08

Gosney K, SK Florentine (2018)

Environmental factors associated with the foliage cover of invasive fairy grass (Lachnagrostis filiformis) in Victoria, Australia.

Environmental science and pollution research international, 25(2):1350-1358.

Fairy grass (Lachnagrostis filiformis) is an Australian native grass that has recently become a major concern for rural communities. Its dried inflorescences are blown by the wind and build up against fences and buildings, becoming a severe fire hazard. Understanding the ecology of fairy grass and its impacts on rural communities is relevant to its management. Four dry lake beds in Western Victoria were selected to determine if environmental factors, such as lake, location, direction, altitude and road type and the covariates of pH, soil salinity, soil moisture and distance to nearest road, are related to the presence of fairy grass. The 'lake' factor was the only environmental parameter that was significantly associated with the presence of this weed.

RevDate: 2018-11-08
CmpDate: 2018-11-08

Lewis JS, Farnsworth ML, Burdett CL, et al (2017)

Biotic and abiotic factors predicting the global distribution and population density of an invasive large mammal.

Scientific reports, 7:44152 pii:srep44152.

Biotic and abiotic factors are increasingly acknowledged to synergistically shape broad-scale species distributions. However, the relative importance of biotic and abiotic factors in predicting species distributions is unclear. In particular, biotic factors, such as predation and vegetation, including those resulting from anthropogenic land-use change, are underrepresented in species distribution modeling, but could improve model predictions. Using generalized linear models and model selection techniques, we used 129 estimates of population density of wild pigs (Sus scrofa) from 5 continents to evaluate the relative importance, magnitude, and direction of biotic and abiotic factors in predicting population density of an invasive large mammal with a global distribution. Incorporating diverse biotic factors, including agriculture, vegetation cover, and large carnivore richness, into species distribution modeling substantially improved model fit and predictions. Abiotic factors, including precipitation and potential evapotranspiration, were also important predictors. The predictive map of population density revealed wide-ranging potential for an invasive large mammal to expand its distribution globally. This information can be used to proactively create conservation/management plans to control future invasions. Our study demonstrates that the ongoing paradigm shift, which recognizes that both biotic and abiotic factors shape species distributions across broad scales, can be advanced by incorporating diverse biotic factors.

RevDate: 2018-11-07

Bieberich J, Lauerer M, Drachsler M, et al (2018)

Species- and developmental stage-specific effects of allelopathy and competition of invasive Impatiens glandulifera on co-occurring plants.

PloS one, 13(11):e0205843 pii:PONE-D-18-17265.

BACKGROUND: Impacts of invasive species on native communities are often difficult to assess, because they depend on a range of factors, such as species identity and traits. Such context-dependencies are poorly understood yet, but knowledge is required to predict the impact of invasions.

MATERIALS AND METHODS: We assessed species- and developmental stage-specificity of competitive and allelopathic effects of the invasive plant Impatiens glandulifera on different developmental stages of four native plant species. While some studies have shown a reduction in plant growth caused by I. glandulifera, the magnitude of its impact is ambiguous. For our study we used seedlings and juveniles of I. glandulifera and the native target species Geum urbanum, Filipendula ulmaria, Urtica dioica, and Salix fragilis (seedlings only of the latter), which often co-occur with I. glandulifera in different habitats. Plants were grown in competition with I. glandulifera or treated with I. glandulifera leaf material, or 2-metoxy-1,4-naphtoquinone (2-MNQ), its supposedly main allelochemical.

RESULTS AND CONCLUSIONS: Overall I. glandulifera had a negative effect on the growth of all target species depending on the species and on the plant's developmental stage. F. ulmaria was the least affected and U. dioica the most, and seedlings were less affected than juveniles. The species-specific response to I. glandulifera may lead to an altered community composition in the field, while growth reduction of seedlings and juveniles should give I. glandulifera an advantage in cases where plant recruitment is crucial. 2-MNQ led to minor reductions in plant growth, suggesting that it may not be the only allelopathic substance of I. glandulifera. Surprisingly, I. glandulifera was not fully tolerant to 2-MNQ. This autotoxicity could contribute to I. glandulifera population dynamics. We conclude that I. glandulifera reduces the growth of native vegetation and alters early successional stages without fully hindering it.

RevDate: 2018-11-07

Poché RM, Poché D, Franckowiak G, et al (2018)

Field evaluation of low-dose warfarin baits to control wild pigs (Sus scrofa) in North Texas.

PloS one, 13(11):e0206070 pii:PONE-D-17-43890.

Wild pigs (Sus scrofa) are a highly detrimental invasive species that occupy a rapidly expanding range within the United States. In Australia, field trials evaluating baits containing 0.09% warfarin resulted in wild pig population reduction >95%. The objective of this study was to conduct an EPA-approved field trial to evaluate the use of bait containing low-dose warfarin (0.01% and 0.005%) in reducing wild pig numbers in Texas. An 8-week field test was conducted in the panhandle ~100 km southeast of Amarillo. Two ~8 km2 treatment plots were selected and each presented with either 0.01% or 0.005% warfarin baits. One control plot (~8 km2) was presented placebo. The baits were delivered using 30 species-specific feeders per plot (n = 90) that kept wildlife from accessing the toxicant. Pig movements and feed consumption were monitored during pre-treatment, treatment, and post-treatment periods. All pigs with VHF transmitters within the 0.005% warfarin-treated plot (n = 14) succumbed to the warfarin (100% mortality). Overall, 35 wild pigs were found dead from warfarin toxicosis, within both treatment plots. Total feed consumption by wild pigs was reduced by ~97.8% and ~96.2% for the 0.005% and 0.01% warfarin baited plots, respectively, indicating the absence of pigs was a result of toxic bait consumption. Results of 97 systematic searches of the treatment plots indicated no warfarin-induced non-target wildlife fatalities. Warfarin residues in wild pig livers averaged 3.69 mg/kg (n = 13) and 2.89 mg/kg (n = 9) for pigs recovered within the 0.005% plot and 0.01% warfarin plot, respectively. This study is the first efficacy field evaluation of a wild pig toxicant conducted in the US. The results suggest low-dose warfarin bait, presented in species-specific feeders, can effectively reduce wild pig numbers and pose minimal risk to non-target wildlife and domestic animals. A product containing warfarin may provide another management tool in reducing wild pig problems.

RevDate: 2018-11-07

Wild S (2018)

South Africa's invasive species guzzle precious water and cost US$450 million a year.

Nature, 563(7730):164-165.

RevDate: 2018-11-07

Divíšek J, Chytrý M, Beckage B, et al (2018)

Similarity of introduced plant species to native ones facilitates naturalization, but differences enhance invasion success.

Nature communications, 9(1):4631 pii:10.1038/s41467-018-06995-4.

The search for traits associated with plant invasiveness has yielded contradictory results, in part because most previous studies have failed to recognize that different traits are important at different stages along the introduction-naturalization-invasion continuum. Here we show that across six different habitat types in temperate Central Europe, naturalized non-invasive species are functionally similar to native species occurring in the same habitat type, but invasive species are different as they occupy the edge of the plant functional trait space represented in each habitat. This pattern was driven mainly by the greater average height of invasive species. These results suggest that the primary determinant of successful establishment of alien species in resident plant communities is environmental filtering, which is expressed in similar trait distributions. However, to become invasive, established alien species need to be different enough to occupy novel niche space, i.e. the edge of trait space.

RevDate: 2018-11-07

Vitale RM, D'Aniello E, Gorbi S, et al (2018)

Fishing for Targets of Alien Metabolites: A Novel Peroxisome Proliferator-Activated Receptor (PPAR) Agonist from a Marine Pest.

Marine drugs, 16(11): pii:md16110431.

Although the chemical warfare between invasive and native species has become a central problem in invasion biology, the molecular mechanisms by which bioactive metabolites from invasive pests influence local communities remain poorly characterized. This study demonstrates that the alkaloid caulerpin (CAU)-a bioactive component of the green alga Caulerpa cylindracea that has invaded the entire Mediterranean basin-is an agonist of peroxisome proliferator-activated receptors (PPARs). Our interdisciplinary study started with the in silico prediction of the ligand-protein interaction, which was then validated by in vivo, ex vivo and in vitro assays. On the basis of these results, we candidate CAU as a causal factor of the metabolic and behavioural disorders observed in Diplodus sargus, a native edible fish of high ecological and commercial relevance, feeding on C. cylindracea. Moreover, given the considerable interest in PPAR activators for the treatment of relevant human diseases, our findings are also discussed in terms of a possible nutraceutical/pharmacological valorisation of the invasive algal biomasses, supporting an innovative strategy for conserving biodiversity as an alternative to unrealistic campaigns for the eradication of invasive pests.

RevDate: 2018-11-07
CmpDate: 2018-11-07

Muchemi SK, Zebitz CPW, Borgemeister C, et al (2018)

Interaction Between Chrysocharis flacilla and Diglyphus isaea (Hymenoptera: Eulophidae), Two Parasitoids of Liriomyza Leafminers.

Journal of economic entomology, 111(2):556-563.

Agromyzid Liriomyza leafminer flies are a major threat to horticultural production in East Africa with low natural control reported. The endoparasitoid Chrysocharis flacilla (Walker; Hymenoptera: Eulophidae) was introduced from Peru into quarantine facilities at ICIPE in Kenya for a leafminer classical biological control program. Interaction assays with one of the dominant local parasitoids, Diglyphus isaea (Walker; Hymenoptera: Eulophidae), using Liriomyza huidobrensis (Blanchard; Diptera: Agromyzidae) was assessed through sole, simultaneous and sequential releases. C. flacilla resulted to superior host parasitism rates over D. isaea. When used separately, specific parasitism rates of D. isaea and C. flacilla were 26.33 ± 2.07% and 60.27 ± 2.53% respectively but, when simultaneously used, the total parasitism rose to 72.96 ± 4.12%. Presence of C. flacilla after D. isaea reduced significantly parasitism rate of D. isaea. Both parasitoids caused separately and simultaneously additionally significant nonreproductive host mortalities of between 48.33 ± 3.75% and 69.33 ± 3.92 for D. isaea and C. flacilla respectively. Sex ratios of C. flacilla and D. isaea F1 progenies were female biased and were not affected by interspecific interactions. Implications of these results for subsequent combined use of C. flacilla and D. isaea against Liriomyza leafminers in East Africa are discussed.

RevDate: 2018-11-07
CmpDate: 2018-11-07

Eyre D, Macarthur R, Haack RA, et al (2018)

Variation in Inspection Efficacy by Member States of Wood Packaging Material Entering the European Union.

Journal of economic entomology, 111(2):707-715.

The use of wood packaging materials (WPMs) in international trade is recognized as a pathway for the movement of invasive pests and as the origin of most introductions of Asian longhorned beetle, Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae) in Europe and North America. Following several pest interceptions on WPM associated with stone imports from China, the European Union (EU) agreed to survey certain categories of imports based on the EU Combined Nomenclature Codes for imports, which are based on the international Harmonized System. Between April 2013 and March 2015, 72,263 relevant consignments were received from China in the EU and 26,008 were inspected. Harmful organisms were detected in 0.9% of the consignments, and 1.1% of the imports did not have markings compliant with the international standard for treating WPM, ISPM 15. There were significant differences between the detection rates of harmful organisms among EU member states. In member states that inspected at least 500 consignments, the rate of detection ranged from 6.9% in Austria and France to 0.0% in Spain and Poland. If this difference in detection rate is the result of differences in the methods and intensity of inspection in different member states then an approximate sevenfold increase in the interception of harmful organisms may be achieved if all states were to achieve detection rates achieved by Austria and France. The EU data from 1999 to 2014 indicated an increasing number of interceptions of Bostrichidae and Cerambycidae since 2010. This study demonstrates that there is an ongoing threat of non-native forest pests being imported on WPM.

RevDate: 2018-11-07
CmpDate: 2018-11-07

Castillo SP, Crego RD, Jiménez JE, et al (2017)

Native-predator-invasive-prey trophic interactions in Tierra del Fuego: the beginning of biological resistance?.

Ecology, 98(9):2485-2487.

RevDate: 2018-11-06

González-Gallina A, Hidalgo-Mihart MG, V Castelazo-Calva (2018)

Conservation implications for jaguars and other neotropical mammals using highway underpasses.

PloS one, 13(11):e0206614 pii:PONE-D-18-11101.

The Nuevo Xcan-Playa del Carmen highway in Quintana Roo, bisects the vegetation corridor connecting two Jaguar Conservation Units (JCUs): Yum Balaam (north) and Sian Ka´an (south). The project´s main goal was to describe differential use of available crossing structures (wildlife underpasses and culverts) by mammals present along this highway. We set 28 camera traps along the 54km stretch of the highway covering wildlife underpasses (10), and culverts such as box culverts (9) and pipes (9) from September 2016 until March 2017. A total of 24 jaguar crossings have been recorded exclusively using wildlife underpasses, including four males and two females. At least 18 other mammal species including five of the target priority species (protected by Mexican law) were documented, all of which were native except for two invasive species. In terms of species using the crossing structures, we identified 13 species using wildlife underpasses, nine using concrete box culverts and 10 using concrete pipes. Wildlife underpasses show higher diversity values (Shannon´s exponential index = 5.8 and Inverse Simpson´s index = 4.66) compared to culverts because they allow bigger species to cross. We recommend more highways along the jaguar´s distribution should develop mitigation measures to allow for wildlife connectivity. Wildlife underpasses, along with retrofitted culverts, could help secure not only the permanence of this species by facilitating the functional connectivity between populations but have positive impacts on other neotropical mammalian fauna as well.

RevDate: 2018-11-06

Singh SP, Inderjit , Singh JS, et al (2018)

Insights on the persistence of pines (Pinus species) in the Late Cretaceous and their increasing dominance in the Anthropocene.

Ecology and evolution, 8(20):10345-10359 pii:ECE34499.

Although gymnosperms were nearly swept away by the rise of the angiosperms in the Late Cretaceous, conifers, and pines (Pinus species) in particular, survived and regained their dominance in some habitats. Diversification of pines into fire-avoiding (subgenus Haploxylon) and fire-adapted (subgenus Diploxylon) species occurred in response to abiotic and biotic factors in the Late Cretaceous such as competition with emerging angiosperms and changing fire regimes. Adaptations/traits that evolved in response to angiosperm-fuelled fire regimes and stressful environments in the Late Cretaceous were key to pine success and are also contributing to a new "pine rise" in some areas in the Anthropocene. Human-mediated activities exert both positive and negative impacts of range size and expansion and invasions of pines. Large-scale afforestation with pines, human-mediated changes to fire regimes, and other ecosystem processes are other contributing factors. We discuss traits that evolved in response to angiosperm-mediated fires and stressful environments in the Cretaceous and that continue to contribute to pine persistence and dominance and the numerous ways in which human activities favor pines.

RevDate: 2018-11-06

Falcón W, RL Tremblay (2018)

From the cage to the wild: introductions of Psittaciformes to Puerto Rico.

PeerJ, 6:e5669 pii:5669.

Introduced psittacine birds can become highly invasive. In this study, we assessed invasions of Psittaciformes in Puerto Rico. We reviewed the literature, public databases, citizen science records, and performed in situ population surveys across the island to determine the historical and current status and distribution of psittacine species. We used count data from Ebird to determine population trends. For species whose populations were increasing, we modelled their potential distribution using niche modeling techniques. We found 46 Psittaciformes in Puerto Rico, of which 26% are only present as pets, at least 29 species have been reported in the wild, and of those, there is evidence that at least 12 species are breeding. Our results indicate that most introduced species which have been detected as established still persist, although mostly in localized areas and small populations. Clear evidence of invasiveness was found for Brotogeris versicolurus and Myiopsitta monachus, which have greatly expanded their range in recent years. Psittacara erythrogenys and Eupsittacula canicularis also showed population increases, although to a lesser degree. The niche models predicted suitable areas for the four species, and also indicate the potential for range expansion. We discuss the factors leading to invasion success, assess the potential impacts, and we discuss possible management strategies and research prospects.

RevDate: 2018-11-06

Ni P, Li S, Lin Y, et al (2018)

Methylation divergence of invasive Ciona ascidians: Significant population structure and local environmental influence.

Ecology and evolution, 8(20):10272-10287 pii:ECE34504.

The geographical expansion of invasive species usually leads to temporary and/or permanent changes at multiple levels (genetics, epigenetics, gene expression, etc.) to acclimatize to abiotic and/or biotic stresses in novel environments. Epigenetic variation such as DNA methylation is often involved in response to diverse local environments, thus representing one crucial mechanism to promote invasion success. However, evidence is scant on the potential role of DNA methylation variation in rapid environmental response and invasion success during biological invasions. In particular, DNA methylation patterns and possible contributions of varied environmental factors to methylation differentiation have been largely unknown in many invaders, especially for invasive species in marine systems where extremely complex interactions exist between species and surrounding environments. Using the methylation-sensitive amplification polymorphism (MSAP) technique, here we investigated population methylation structure at the genome level in two highly invasive model ascidians, Ciona robusta and C. intestinalis, collected from habitats with varied environmental factors such as temperature and salinity. We found high intrapopulation methylation diversity and significant population methylation differentiation in both species. Multiple analyses, such as variation partitioning analysis, showed that both genetic variation and environmental factors contributed to the observed DNA methylation variation. Further analyses found that 24 and 20 subepiloci were associated with temperature and/or salinity in C. robusta and C. intestinalis, respectively. All these results clearly showed significant methylation divergence among populations of both invasive ascidians, and varied local environmental factors, as well as genetic variation, were responsible for the observed DNA methylation patterns. The consistent findings in both species here suggest that DNA methylation, coupled with genetic variation, may facilitate local environmental adaptation during biological invasions, and DNA methylation variation molded by local environments may contribute to invasion success.

RevDate: 2018-11-06

Doherty-Bone TM, Dunn AM, Brittain J, et al (2018)

Invasive alien shredders clear up invasive alien leaf litter.

Ecology and evolution, 8(20):10049-10056 pii:ECE34430.

Biological invasions have the potential to alter ecosystem processes profoundly, but invaders are rarely found alone. Interactions between different invasive alien species, and their cumulative impact on ecosystem functioning, have led to hypotheses of invasion meltdown whereby effects become additive leading to further ecosystem stress. Invasive riparian plants (e.g., Rhododendron ponticum) deposit leaf litter in freshwaters, which may be unconsumed by indigenous species, potentially affecting habitat heterogeneity and flow of energy to the food web. However, invasive alien decapod crustaceans are effective consumers of leaf litter, and it was hypothesized that they would also consume inputs of invasive riparian leaf litter. This study shows that invasive alien signal crayfish (Pacifastacus leniusculus) and Chinese mitten crab (Eriocheir sinensis) effectively break down different types of leaf litter, including invasive alien R. ponticum, at higher rates than indigenous white-clawed crayfish. Secondary products were more varied, with more fine particulate organic matter generated for the less palatable alien leaf litter species. Leaf species caused different changes in body mass of decapods but effects were heterogeneous by leaf and decapod: P. leniusculus showed lower mass loss when consuming R. ponticum while E. sinensis lost mass when consuming A. pseudoplatanus. Impacts of riparian invasions on detritus accumulation in freshwaters are thus potentially buffered by invasive alien decapods, illustrating a need for a more detailed consideration of both positive and negative interspecific feedbacks during biological invasions.

RevDate: 2018-11-06
CmpDate: 2018-11-06

Chapman DS, Scalone R, Štefanić E, et al (2017)

Mechanistic species distribution modeling reveals a niche shift during invasion.

Ecology, 98(6):1671-1680.

Niche shifts of nonnative plants can occur when they colonize novel climatic conditions. However, the mechanistic basis for niche shifts during invasion is poorly understood and has rarely been captured within species distribution models. We quantified the consequence of between-population variation in phenology for invasion of common ragweed (Ambrosia artemisiifolia L.) across Europe. Ragweed is of serious concern because of its harmful effects as a crop weed and because of its impact on public health as a major aeroallergen. We developed a forward mechanistic species distribution model based on responses of ragweed development rates to temperature and photoperiod. The model was parameterized and validated from the literature and by reanalyzing data from a reciprocal common garden experiment in which native and invasive populations were grown within and beyond the current invaded range. It could therefore accommodate between-population variation in the physiological requirements for flowering, and predict the potentially invaded ranges of individual populations. Northern-origin populations that were established outside the generally accepted climate envelope of the species had lower thermal requirements for bud development, suggesting local adaptation of phenology had occurred during the invasion. The model predicts that this will extend the potentially invaded range northward and increase the average suitability across Europe by 90% in the current climate and 20% in the future climate. Therefore, trait variation observed at the population scale can trigger a climatic niche shift at the biogeographic scale. For ragweed, earlier flowering phenology in established northern populations could allow the species to spread beyond its current invasive range, substantially increasing its risk to agriculture and public health. Mechanistic species distribution models offer the possibility to represent niche shifts by varying the traits and niche responses of individual populations. Ignoring such effects could substantially underestimate the extent and impact of invasions.

RevDate: 2018-11-06
CmpDate: 2018-11-06

Zhu X, Weston PA, Skoneczny D, et al (2017)

Ecology and genetics affect relative invasion success of two Echium species in southern Australia.

Scientific reports, 7:42792 pii:srep42792.

Echium plantagineum and E. vulgare are congeneric exotics first introduced to Australia in the early 1800 s. There, E. plantagineum is now highly invasive, whereas E. vulgare has a limited distribution. Studies were conducted to evaluate distribution, ecology, genetics and secondary chemistry to shed light on factors associated with their respective invasive success. When sampled across geographically diverse locales, E. plantagineum was widespread and exhibited a small genome size (1 C = 0.34 pg), an annual life cycle, and greater genetic diversity as assessed by DNA sequence analysis. It was found frequently in areas with temperature extremes and low rainfall. In contrast, E. vulgare exhibited a larger genome size (1 C = 0.43 pg), a perennial lifecycle, less chloroplast genetic diversity, and occurred in areas with lower temperatures and higher rainfall. Twelve chloroplast haplotypes of E. plantagineum were evident and incidence aligned well with reported historical introduction events. In contrast, E. vulgare exhibited two haplotypes and was found only sporadically at higher elevations. Echium plantagineum possessed significantly higher levels of numerous pyrrolizidine alkaloids involved in plant defence. We conclude that elevated genetic diversity, tolerance to environmental stress and capacity for producing defensive secondary metabolites have contributed to the successful invasion of E. plantagineum in Australia.

RevDate: 2018-11-06
CmpDate: 2018-11-06

Hogan MB, Allenback GL, Chawla V, et al (2016)

Sensitization to a nonnative plant without exposure is a marker of panallergen sensitization.

The journal of allergy and clinical immunology. In practice, 4(5):982-983.e1.

RevDate: 2018-11-05

Maw MM, Pan X, Peng Z, et al (2018)

A Changeable Lab-on-a-Chip Detector for Marine Nonindigenous Microorganisms in Ship's Ballast Water.

Micromachines, 9(1): pii:mi9010020.

The spread and invasion of many nonindigenous species in the ship's ballast water around the world has been a hazard and threat to ecology, economy, and human health. The rapid and accurate detection of marine invasive species in ship's ballast water is essential. This article is aimed at analysing ballast water quality by means of a changeable microfluidic chip detector thus comply with the D-2 standard of ship's ballast water management and sediment convention. The detection system was designed through the integration of microfluidic chip technology, the impedance pulse sensing and LED light induced chlorophyll fluorescence (LED-LICF) detection. This system can measure the number, size, shape, and volume of targeted microorganisms, and it can also determine the chlorophyll fluorescence intensity, which is an important factor in analysing the activity of phytoplankton. The targeted samples were Chlorella volutis, Dunaliella salina, Platymonas subcordiformis, Chrysophytes, Escherichia coli, and Enterococci. The whole detection or operation can be accomplished through online detection in a few minutes with using micron volume of the sample solution. The valid data outputs are simultaneously displayed in terms of both impedance pulse amplitudes and fluorescent intensity signals. The detection system is designed for multi-sizes real time detection through changing the microchannel sizes on the microfluidic chip. Because it can successfully detect the label-free microorganisms, the system can be applicable to in-situ detections with some modifications to the system.

RevDate: 2018-11-04

Bai X, K Acharya (2018)

Uptake of endocrine-disrupting chemicals by quagga mussels (Dreissena bugensis) in an urban-impacted aquatic ecosystem.

Environmental science and pollution research international pii:10.1007/s11356-018-3320-4 [Epub ahead of print].

Untreated organic contaminants in municipal wastewater, such as endocrine-disrupting chemicals (EDCs), have become a significant issue in aquatic ecosystems, particularly in freshwater bodies that receive wastewater discharge. This has raised concerns about the accumulation of EDCs in aquatic species via continuous exposure. This study evaluated the uptake of EDCs by quagga mussels (Dreissena bugensis), an invasive species in a water supply reservoir. The field sampling results showed that steroid hormones were not detected in the water samples, and only pharmaceuticals and personal care products were present (0.49 to 36 ng/L). Additionally, testosterone was the most abundant steroid in the mussel tissue (6.3 to 20 ng/g dry weight), and other synthetic chemicals (i.e., bisphenol A, triclosan, and salicylic acid) were also detected in the mussel tissue (24 to 47 ng/g dry weight). After being exposed to exogenous EDCs for 7, 21, and 42 days under controlled laboratory conditions, testosterone was not detected in the mussel anymore, but bisphenol A, triclosan, and salicylic acid were found at relatively high levels in the mussel tissue, although the concentrations did not increase over time. Overall, the study demonstrated the uptake of EDCs in quagga mussels, which suggests that this species can be used to reflect water quality deterioration in aquatic ecosystems.

RevDate: 2018-11-05
CmpDate: 2018-11-05

Diamond JS, McLaughlin DL, Slesak RA, et al (2018)

Forested versus herbaceous wetlands: Can management mitigate ecohydrologic regime shifts from invasive emerald ash borer?.

Journal of environmental management, 222:436-446.

Wetlands self-organize through reciprocal controls between vegetation and hydrology, but external disturbance may disrupt these feedbacks with consequent changes to ecosystem state. Imminent and widespread emerald ash borer (EAB) infestation throughout North American forested wetlands has raised concern over possible ecosystem state shifts (i.e., wetter, more herbaceous systems) and loss of forest function, calling for informed landscape-scale management strategies. In response, we employed a large-scale manipulative study to assess the ecohydrologic response of black ash wetlands to three alternative EAB management strategies: 1) a do-nothing approach (i.e., simulated EAB infestation via tree girdling), 2) a preemptive, complete harvesting approach (i.e., clearcut), and 3) an overstory replacement approach via group selection. We analyzed six years of daily water table and evapotranspiration (ET) dynamics in six blocks comprising black ash wetlands (controls) and management strategy treatments to quantify potential for hydrologic change and subsequent recovery. In both the do-nothing approach and complete harvesting approach, we found persistent changes in hydrologic regime defined by shallower water tables and lower ET rates coupled with increased herbaceous vegetation growth, indicating ecosystem state shifts driven by vegetation-water table interactions. The do-nothing approach showed the least hydrologic recovery after five years, which we attribute to reduction in overstory transpiration as well as greater shade (via standing dead trees) that reduces open water evaporation and herbaceous layer transpiration compared to complete harvesting. We found no evidence of ecohydrologic disturbance in the overstory replacement approach, highlighting its potential as a management strategy to preserve forested wetland habitat if periodically executed over time before EAB infestation. Although the scale of potential disturbance is daunting, our findings provide a baseline assessment for forest managers to develop preemptive mitigation strategies to address the threat of EAB to ecological functions in black ash wetlands.

RevDate: 2018-11-05
CmpDate: 2018-11-05

Jaspers C, Marty L, T Kiørboe (2018)

Selection for life-history traits to maximize population growth in an invasive marine species.

Global change biology, 24(3):1164-1174.

Species establishing outside their natural range, negatively impacting local ecosystems, are of increasing global concern. They often display life-history features characteristic for r-selected populations with fast growth and high reproduction rates to achieve positive population growth rates (r) in invaded habitats. Here, we demonstrate substantially earlier maturation at a 2 orders of magnitude lower body mass at first reproduction in invasive compared to native populations of the comb jelly Mnemiopsis leidyi. Empirical results are corroborated by a theoretical model for competing life-history traits that predicts maturation at the smallest possible size to optimize r, while individual lifetime reproductive success (R0), optimized in native populations, is near constant over a large range of intermediate maturation sizes. We suggest that high variability in reproductive tactics in native populations is an underappreciated determinant of invasiveness, acting as substrate upon which selection can act during the invasion process.

RevDate: 2018-11-02

Thorp CJ, Alexander ME, Vonesh JR, et al (2018)

Size-dependent functional response of Xenopus laevis feeding on mosquito larvae.

PeerJ, 6:e5813 pii:5813.

Predators can play an important role in regulating prey abundance and diversity, determining food web structure and function, and contributing to important ecosystem services, including the regulation of agricultural pests and disease vectors. Thus, the ability to predict predator impact on prey is an important goal in ecology. Often, predators of the same species are assumed to be functionally equivalent, despite considerable individual variation in predator traits known to be important for shaping predator-prey interactions, like body size. This assumption may greatly oversimplify our understanding of within-species functional diversity and undermine our ability to predict predator effects on prey. Here, we examine the degree to which predator-prey interactions are functionally homogenous across a natural range of predator body sizes. Specifically, we quantify the size-dependence of the functional response of African clawed frogs (Xenopus laevis) preying on mosquito larvae (Culex pipiens). Three size classes of predators, small (15-30 mm snout-vent length), medium (50-60 mm) and large (105-120 mm), were presented with five densities of prey to determine functional response type and to estimate search efficiency and handling time parameters generated from the models. The results of mesocosm experiments showed that type of functional response of X. laevis changed with size: small predators exhibited a Type II response, while medium and large predators exhibited Type III responses. Functional response data showed an inversely proportional relationship between predator attack rate and predator size. Small and medium predators had highest and lowest handling time, respectively. The change in functional response with the size of predator suggests that predators with overlapping cohorts may have a dynamic impact on prey populations. Therefore, predicting the functional response of a single size-matched predator in an experiment may misrepresent the predator's potential impact on a prey population.

RevDate: 2018-11-02

Ximénez-Embún MG, González-Guzmán M, Arbona V, et al (2018)

Plant-Mediated Effects of Water Deficit on the Performance of Tetranychus evansi on Tomato Drought-Adapted Accessions.

Frontiers in plant science, 9:1490.

Climate change is expected to increase drought periods and the performance and dispersal of some invasive species such as Tetranychus evansi, which has been reported to take advantage of the nutritional changes induced by water-shortage on the tomato cultivar Moneymaker (MM). We have examined the implications for mite's biology of four accessions of the drought-adapted tomatoes, "Tomàtiga de Ramellet" (TR), under moderate drought stress. Mite performance was enhanced by drought in two accessions (TR61 and TR154), but not in the other two accessions (TR58 and TR126). We selected one accession of each outcome (i.e., TR154 and TR126) to further analyze plant nutritional parameters. We found that free sugars and most essential amino acids for mites were induced by drought and/or mite infestation on MM and TR154 plants, whereas sugars were not altered and a reduced number of essential amino acids were induced by drought in TR126. Remarkably, mite performance was enhanced by leaf infiltration of free sugars, essential amino acids mixture, and L-proline on well-watered MM and by free sugars on drought-stressed TR126 plants. These results indicate a positive link between the induction of soluble carbohydrates and amino acids used by the plant for osmotic adjustment and mite performance. The effects of drought and/or mite infestation on the defense response of plants was analyzed at three levels: phytohormone accumulation, the transcript levels of marker genes linked to jasmonates (JAs), salicylic acid (SA), and abscisic acid (ABA) pathways, and the activity of defense proteins. The ability of T. evansi to downregulate the accumulation of defense-related phytohormones was noted on MM and the two TR accessions analyzed (TR126 and TR154), though differences in the induction of protein defense genes and activities by drought and/or mite infestation were observed among them. These results emphasize the importance of studying plant biotic and abiotic stress factors in combination and provides an experimental framework for screening drought-tolerant tomato accessions that will be also resistant to herbivore mites.

RevDate: 2018-11-02

Page H, Sweeney A, Pilko A, et al (2018)

Underlying mechanisms and ecological context of variation in exploratory behavior of the Argentine ant, Linepithema humile.

The Journal of experimental biology pii:jeb.188722 [Epub ahead of print].

Uncovering how and why animals explore their environment is fundamental for understanding population dynamics, the spread of invasive species, species interactions etc. In social animals, individuals within a group can vary in their exploratory behavior and the behavioral composition of the group can determine its collective success. Workers of the invasive Argentine ant (Linepithema humile) exhibit individual variation in exploratory behavior, which affects the colony's collective nest selection behavior. Here we examine the mechanisms underlying this behavioral variation in exploratory behavior and determine its implications for the ecology of this species. We first establish that individual variation in exploratory behavior is repeatable and consistent across situations. We then show a relationship between exploratory behavior and the expression of genes that have been previously linked with other behaviors in social insects. Specifically, we find a negative relationship between exploratory behavior and the expression of the foraging (Lhfor) gene. Finally, we determine how colonies allocate exploratory individuals in natural conditions. We find that ants from inside the nest are the least exploratory individuals, while workers on newly formed foraging trails are the most exploratory individuals. Furthermore, we found temporal differences throughout the year - in early-mid spring, when new resources emerge, workers are more exploratory than at the end of winter, potentially allowing the colony to find and exploit new resources. These findings reveal the importance of individual variation in behavior for the ecology of social animals.

RevDate: 2018-11-02
CmpDate: 2018-11-02

Muchemi SK, Zebitz CPW, Borgemeister C, et al (2018)

Interaction Between Two Leafminer Parasitoids, Halticoptera arduine (Hymenoptera: Pteromalidae) and Diglyphus isaea (Hymenoptera: Eulophidae), in the Management of Liriomyza huidobrensis (Diptera: Agromyzidae).

Environmental entomology, 47(3):692-699.

Liriomyza spp., leafminer flies (Mik; Diptera: Agromyzidae), are economically important quarantine pests that puncture and mine leaves and fruits of various horticultural crops worldwide, affecting yield and trade. Halticoptera arduine (Walker; Hymenoptera: Pteromalidae), a key parasitoid from the pests' areas of origin in South America, was introduced as a potential alternative management strategy. Prior to H. arduine release, its potential interactions with the dominant local ectoparasitoid, Diglyphus isaea (Walker; Hymenoptera: Eulophidae), were assessed. Halticoptera arduine and D. isaea were released in single, sequential and simultaneous combinations on Liriomyza huidobrensis (Blanchard; Diptera: Agromyzidae) to evaluate possible effect on the parasitism rate, reproduction and host mortality. The combination of both parasitoids did not significantly affect the specific parasitism rates of either of them, an indication that H. arduine and D. isaea can coexist. Parasitism rates of the exotic H. arduine were significantly superior to the indigenous D. isaea in all release combinations except when both species were released simultaneously. While 50 individuals of D. isaea resulted only in 21.23 ± 2.1% parasitism, 50 parasitoids composed of 25 H. arduine and 25 D. isaea caused 53.27 ± 4.99%. Both parasitoids further induced significant nonreproductive host mortalities. Both parasitoids' F1 progenies sex ratios were female-biased in all parasitoid release combinations except in single release of D. isaea with a balanced sex ratio. The improvement in D. isaea's sex ratio induced by the presence of H. arduine suggests a synergetic effect on D. isaea's reproductive performance. The introduction of H. arduine in horticulture production systems may therefore improve natural control of Liriomyza leafminers in East Africa.

RevDate: 2018-11-02
CmpDate: 2018-11-02

Chen W, ES Adams (2018)

The Distribution and Habitat Affinities of the Invasive Ant Myrmica rubra (Hymenoptera: Formicidae) in Southern New England.

Environmental entomology, 47(3):527-534.

The Eurasian ant Myrmica rubra (L.) (Hymenoptera: Formicidae) was first discovered in North America in the early 1900s in Massachusetts. Populations have since appeared in at least seven states within the United States and in seven Canadian provinces. We conducted a systematic search for the ant across southern New England-the states of Connecticut, Massachusetts, and Rhode Island-where M. rubra is spreading from multiple loci. The species occurs in two large regions in Massachusetts, each spanning approximately 75 km, and in several smaller populations in Massachusetts and Rhode Island. No populations were discovered anywhere in Connecticut or across large expanses of central Massachusetts and northern Rhode Island, despite the presence of apparently favorable habitat. This pattern of distribution suggests a combination of long-distance dispersal by human transport coupled with slow local spread. Resurveys of sites previously known to support M. rubra showed that populations persist for decades. Within invaded areas, M. rubra was strongly associated with particular habitats. Colonies were most prevalent in freshwater wetlands and in moist forests near wetlands and water; they were uncommon in drier forests and were rare in open habitats outside of wetlands. The slow rate of spread over the last 110 yr suggests that the ants do not easily disperse between patches of suitable habitat.

RevDate: 2018-11-02
CmpDate: 2018-11-02

Brand P, Lin W, BR Johnson (2018)

The Draft Genome of the Invasive Walking Stick, Medauroidea extradendata, Reveals Extensive Lineage-Specific Gene Family Expansions of Cell Wall Degrading Enzymes in Phasmatodea.

G3 (Bethesda, Md.), 8(5):1403-1408 pii:g3.118.200204.

Plant cell wall components are the most abundant macromolecules on Earth. The study of the breakdown of these molecules is thus a central question in biology. Surprisingly, plant cell wall breakdown by herbivores is relatively poorly understood, as nearly all early work focused on the mechanisms used by symbiotic microbes to breakdown plant cell walls in insects such as termites. Recently, however, it has been shown that many organisms make endogenous cellulases. Insects, and other arthropods, in particular have been shown to express a variety of plant cell wall degrading enzymes in many gene families with the ability to break down all the major components of the plant cell wall. Here we report the genome of a walking stick, Medauroidea extradentata, an obligate herbivore that makes uses of endogenously produced plant cell wall degrading enzymes. We present a draft of the 3.3Gbp genome along with an official gene set that contains a diversity of plant cell wall degrading enzymes. We show that at least one of the major families of plant cell wall degrading enzymes, the pectinases, have undergone a striking lineage-specific gene family expansion in the Phasmatodea. This genome will be a useful resource for comparative evolutionary studies with herbivores in many other clades and will help elucidate the mechanisms by which metazoans breakdown plant cell wall components.

RevDate: 2018-11-02
CmpDate: 2018-11-02

Kim S, Kang J, Megonigal JP, et al (2018)

Impacts of Phragmites australis Invasion on Soil Enzyme Activities and Microbial Abundance of Tidal Marshes.

Microbial ecology, 76(3):782-790.

The rapid expansion of Phragmites australis in brackish marshes of the East Coast of the USA has drawn much attention, because it may change vegetation diversity and ecosystem functions. In particular, higher primary production of Phragmites than that of other native species such as Spartina patens and Schoenoplectus americanus has been noted, suggesting possible changes in carbon storage potential in salt marshes. To better understand the long-term effect of the invasion of Phragmites on carbon storage, however, information on decomposition rates of soil organic matter is essential. To address this issue, we compared microbial enzyme activities and microbial functional gene abundances (fungi, laccase, denitrifier, and methanogens) in three depths of soils with three different plants in a brackish marsh in Maryland, USA. Laccase and phenol oxidase activities were measured to assess the decomposition potential of recalcitrant carbon while β-glucosidase activity was determined as proxy for cellulose decomposition rate. Microbial activities near the surface (0-15 cm) were the highest in Spartina-community sites followed by Phragmites- and Schoenoplectus-community sites. A comparison of stable isotopic signatures (δ13C and δ15N) of soils and plant leaves suggests that deep organic carbon in the soils mainly originated from Spartina, and only the surface soils may have been influenced by Phragmites litter. In contrast, fungal, laccase, and denitrifier abundances determined by real-time qPCR exhibited no discernible patterns among the surface soils of the three vegetation types. However, the abundance of methanogens was higher in the deep Phragmites-community soil. Therefore, Phragmites invasion will accelerate CH4 emission by greater CH4 production in deep soils with abundant methanogens, although enzymatic mechanisms revealed the potential for larger C accumulation by Phragmites invasion in salt marshes in the east coast of the USA.

RevDate: 2018-11-02
CmpDate: 2018-11-02

Carrasco D, Desurmont GA, Laplanche D, et al (2018)

With or without you: Effects of the concurrent range expansion of an herbivore and its natural enemy on native species interactions.

Global change biology, 24(2):631-643.

Global climatic changes may lead to the arrival of multiple range-expanding species from different trophic levels into new habitats, either simultaneously or in quick succession, potentially causing the introduction of manifold novel interactions into native food webs. Unraveling the complex biotic interactions between native and range-expanding species is critical to understand the impact of climate change on community ecology, but experimental evidence is lacking. In a series of laboratory experiments that simulated direct and indirect species interactions, we investigated the effects of the concurrent arrival of a range-expanding insect herbivore in Europe, Spodoptera littoralis, and its associated parasitoid Microplitis rufiventris, on the native herbivore Mamestra brassicae, and its associated parasitoid Microplitis mediator, when co-occurring on a native plant, Brassica rapa. Overall, direct interactions between the herbivores were beneficial for the exotic herbivore (higher pupal weight than the native herbivore), and negative for the native herbivore (higher mortality than the exotic herbivore). At the third trophic level, both parasitoids were unable to parasitize the herbivore they did not coexist with, but the presence of the exotic parasitoid still negatively affected the native herbivore (increased mortality) and the native parasitoid (decreased parasitism rate), through failed parasitism attempts and interference effects. Our results suggest different interaction scenarios depending on whether S. littoralis and its parasitoid arrive to the native tritrophic system separately or concurrently, as the negative effects associated with the presence of the parasitoid were dependent on the presence of the exotic herbivore. These findings illustrate the complexity and interconnectedness of multitrophic changes resulting from concurrent species arrival to new environments, and the need for integrating the ecological effects of such arrivals into the general theoretical framework of global invasion patterns driven by climatic change.

RevDate: 2018-11-01

Ferronato P, Woch AL, Soares PL, et al (2018)

A Phylogeographic Approach to the Drosophila suzukii (Diptera: Drosophilidae) Invasion in Brazil.

Journal of economic entomology pii:5153298 [Epub ahead of print].

Biological invasions have reached large parts of the globe, due to human actions across the planet. Drosophila suzukii (Matsumura, 1931) is a globally invasive species, always associated with enormous and costly damage to agricultural crops. Native to Southeast Asia, D. suzukii recently (i.e., 2013) invaded and is dispersing through South America. Here, we used a phylogeographic approach based on the cytochrome c oxidase subunit I gene fragment to explore the invasion dynamics of D. suzukii populations in Brazil. We identified five haplotypes and moderate genetic diversity in Brazilian populations, which are undergoing demographic and spatial expansion. The analyses of molecular variance indicated a high genetic structure among the populations, which is partially explained by their morphoclimatic origin and invasion history. Drosophila suzukii expanded from southern to southeastern Brazil, aided by human-mediated transport of fruits from region to region. The sharing of haplotypes among Brazilian and other invaded regions of the world suggests a single invasion event of D. suzukii in Brazil, originating from previously invaded areas (e.g., North America and Europe). The rapid geographic dispersal and wide variety of fruits attacked by of D. suzukii require immediate implementation of control strategies (legal and phytosanitary) to manage this pest in Brazil.

RevDate: 2018-11-01

Rosso F, Tagliapietra V, Albanese D, et al (2018)

Reduced diversity of gut microbiota in two Aedes mosquitoes species in areas of recent invasion.

Scientific reports, 8(1):16091 pii:10.1038/s41598-018-34640-z.

Aedes mosquitoes are considered highly successful global invasive species and vectors of several pathogens of relevance for public health. Their midgut's microbiota can play an important role in affecting not only their vectorial competence but also their fitness, physiology, food digestion, metabolism, immunity and adaptation to new environmental conditions. Using high-throughput sequencing we compared the microbiota of Aedes albopictus collected in Italy with those reported in populations from France and Vietnam. We also analysed Aedes koreicus gut microbiota for the first time. We found remarkable individual difference along with common bacterial taxa in both species. Ae. albopictus collected in Italy had a lower richness and a different composition of microbiota in respect to specimens collected in France and Vietnam. It also showed a core microbiota formed mainly of bacteria of the genus Pseudomonas. Overall, the two Aedes species (Ae. albopictus and Ae. koreicus) collected in Italy, showed a large core microbiota with 75.98% of the identified Operational Taxonomic Units. Furthermore, Ae. albopictus had 2.5% prevalence of Wolbachia and 0.07% of Asaia spp, while Ae. koreicus had 14.42% of Asaia spp. and no Wolbachia. This study provides new informations on the spatial variation of the midgut bacterial communities in mosquitoes of medical relevance within areas of recent invasion and provide the basis for further studies aimed at assessing the effects of such variation on vectorial capacity for a range of pathogens.

RevDate: 2018-11-01

Savadova K, Mazur-Marzec H, Karosienė J, et al (2018)

Effect of Increased Temperature on Native and Alien Nuisance Cyanobacteria from Temperate Lakes: An Experimental Approach.

Toxins, 10(11): pii:toxins10110445.

In response to global warming, an increase in cyanobacterial blooms is expected. In this work, the response of two native species of Planktothrix agardhii and Aphanizomenon gracile, as well as the response of two species alien to Europe-Chrysosporum bergii and Sphaerospermopsis aphanizomenoides-to gradual temperature increase was tested. The northernmost point of alien species distribution in the European continent was recorded. The tested strains of native species were favoured at 20⁻28 °C. Alien species acted differently along temperature gradient and their growth rate was higher than native species. Temperature range of optimal growth rate for S. aphanizomenoides was similar to native species, while C. bergii was favoured at 26⁻30 °C but sensitive at 18⁻20 °C. Under all tested temperatures, non-toxic strains of the native cyanobacteria species prevailed over the toxic ones. In P. agardhii, the decrease in concentration of microcystins and other oligopeptides with the increasing temperature was related to higher growth rate. However, changes in saxitoxin concentration in A. gracile under different temperatures were not detected. Accommodating climate change perspectives, the current work showed a high necessity of further studies of temperature effect on distribution and toxicity of both native and alien cyanobacterial species.

RevDate: 2018-11-01
CmpDate: 2018-11-01

Kuchta R, Choudhury A, T Scholz (2018)

Asian Fish Tapeworm: The Most Successful Invasive Parasite in Freshwaters.

Trends in parasitology, 34(6):511-523.

The Asian fish tapeworm (AFT), Schyzocotyle acheilognathi, is a notorious and highly successful invasive parasite reported in a wide spectrum of freshwater fishes, and new reports of its spread continue to emerge. To date, no thorough review of its worldwide distribution and host associations is available. In the present work, we collected information from 651 articles up until 2017, from which we updated the number of the hosts to 312 fish species and 11 non-fish species, which is quite unusual among helminths. The AFT has spread to all but one continent (Antarctica). The highest number of records are from North America, followed by Asia and Europe. A key feature of its invasive success is its broad environmental tolerance.

RevDate: 2018-11-01
CmpDate: 2018-11-01

Sakata Y, Craig TP, Itami JK, et al (2017)

Parallel environmental factors drive variation in insect density and plant resistance in the native and invaded ranges.

Ecology, 98(11):2873-2884.

Geographic variation in the traits of a species is shaped by variation in abiotic conditions, biotic interactions, and evolutionary history of its interactions with other species. We studied the geographic variation in the density of the lace bug, Corythucha marmorata, and the resistance of tall goldenrod Solidago altissima to the lace bug herbivory in their native range in the United States and invaded range in Japan. We conducted field surveys and reciprocal transplant experiments to examine what abiotic and biotic factors influence variation in lace bug density, and what ecological and evolutionary factors predict the resistance of the host plant between and within the native and invaded ranges. Lace bug density was higher throughout the invaded range than in the native range, higher in populations with warmer climates, and negatively affected by foliage damage by other insects in both ranges. The higher lace bug density in warmer climates was explained by the shorter developmental time of the lace bugs at higher temperatures. The resistance of S. altissima to lace bugs was higher in populations with lace bugs compared to populations without lace bugs in both native and invaded ranges, indicating that the evolutionary history of the interaction with the lace bugs was responsible for the variation in S. altissima resistance in both ranges. The present study revealed that abiotic and biotic factors, including temperature and other herbivorous insects, can drive the geographic variation in lace bug density, which in turn selects for variation in plant resistance in both in the native and invaded ranges. We conclude that the novel combination of factors such as higher temperature and lower number of other herbivorous insects is responsible for the higher lace bug density in the invaded range than in the native range.

RevDate: 2018-10-31

Doenz CJ, Bittner D, Vonlanthen P, et al (2018)

Rapid buildup of sympatric species diversity in Alpine whitefish.

Ecology and evolution, 8(18):9398-9412 pii:ECE34375.

Adaptive radiations in postglacial fish offer excellent settings to study the evolutionary mechanisms involved in the rapid buildup of sympatric species diversity from a single lineage. Here, we address this by exploring the genetic and ecological structure of the largest Alpine whitefish radiation known, that of Lakes Brienz and Thun, using microsatellite data of more than 2000 whitefish caught during extensive species-targeted and habitat-randomized fishing campaigns. We find six strongly genetically and ecologically differentiated species, four of which occur in both lakes, and one of which was previously unknown. These four exhibit clines of genetic differentiation that are paralleled in clines of eco-morphological and reproductive niche differentiation, consistent with models of sympatric ecological speciation along environmental gradients. In Lake Thun, we find two additional species, a profundal specialist and a species introduced in the 1930s from another Alpine whitefish radiation. Strong genetic differentiation between this introduced species and all native species of Lake Thun suggests that reproductive isolation can evolve among allopatric whitefish species within 15,000 years and persist in secondary sympatry. Consistent with speciation theory, we find stronger correlations between genetic and ecological differentiation for sympatrically than for allopatrically evolved species.

RevDate: 2018-10-31

Thibault M, Masse F, Pujapujane A, et al (2018)

"Liaisons dangereuses": The invasive red-vented bulbul (Pycnonotus cafer), a disperser of exotic plant species in New Caledonia.

Ecology and evolution, 8(18):9259-9269 pii:ECE34140.

The biodiversity hotspot of New Caledonia hosts high levels of endemism (74% of flora) that is threatened increasingly by climate change, habitat reduction, and invasive species. The fruit-eating red-vented bulbul (Pycnonotus cafer) is currently invading the main island of the archipelago, and its recent dispersal out of urbanized habitats raises questions about its potential to disperse noxious plant seeds along urban corridors and beyond. Indeed, the red-vented bulbul is considered a vector of several introduced plant species in its alien range including Miconia calvescens, Lantana camara, and Schinus terebinthifolius. We conducted a quantitative assessment of the bulbul's fruits consumption by analyzing the gut contents of shot birds. We estimated gut passage times for four species of fruit found in gut contents (S. terebinthifolius, Myrtastrum rufopunctatum, Passiflora suberosa, and Ficus prolixa) and tested the effects of bird digestion on seed germination rates for two species. Finally, we monitored the movements of individual VHF radio-tagged red-vented bulbuls. All of the consumed fruit species we identified here have red fleshy diaspore, including fruit of the shrub M. rufopunctatum that occurred frequently (9.6%) in bulbul gut samples. Median gut passage times were short (15-41 min), corresponding to short-distance seed transportation (77-92 m). The effect of gut passage was positive for the germination of the invasive S. terebinthifolius and negative for the endemic M. rufopunctatum, suggesting a potential bias in the contribution to the dispersal toward alien species. This study provides the first integrated assessment of mechanisms involved in the seed dispersal effectiveness of this high-concern invasive bird species that is expected to face similar plant communities in most of its alien range in tropical islands. More generally, our results enhance knowledge of synergies between non-native frugivores and plant species dispersal.

RevDate: 2018-10-31

Robinson CV, Garcia de Leaniz C, James J, et al (2018)

Genetic diversity and parasite facilitated establishment of the invasive signal crayfish (Pacifastacus leniusculus) in Great Britain.

Ecology and evolution, 8(18):9181-9191 pii:ECE34235.

Successful establishment of non-native species is strongly influenced, among other factors, by the genetic variation of founding populations, which can be enhanced by multiple introductions through admixture. Coexisting pathogens can also facilitate the establishment of non-native species by detrimentally impacting on the native fauna acting as novel weapons. The signal crayfish (Pacifastacus leniusculus) is a highly invasive species, which has caused mass declines of native crayfish in Europe through displacement and transmission of the oomycete Aphanomyces astaci (crayfish plague), which is typically lethal to native European crayfish. However, whether Aphanomyces astaci may have facilitated the invasion of the signal crayfish is not known. We estimated the genetic diversity at microsatellite DNA loci, effective population size, and potential origins of seven infected and noninfected signal crayfish populations in Europe and one founder population in North America. Approximate Bayesian computation analysis and population structuring suggested multiple host introductions from diverse source populations, as well as higher heterozygosity among infected than uninfected populations, which could reflect a fitness advantage. Low effective population size, moderate heterozygosity, and lack of isolation by distance suggest that some invasive signal crayfish populations may not be fully established or that their genetic diversity may have been reduced by eradication attempts.

RevDate: 2018-10-31

Gallego-Tévar B, Rubio-Casal AE, de Cires A, et al (2018)

Phenotypic plasticity of polyploid plant species promotes transgressive behaviour in their hybrids.

AoB PLANTS, 10(5):ply055 pii:ply055.

Hybridization is a frequent process that leads to relevant evolutionary consequences, but there is a lack of studies regarding the relationships of the variability of the response of parental plant species to environmental gradients and the responses of their hybrids at a phenotypic level. We designed an experiment in which we exposed two reciprocal cordgrass hybrids, Spartina maritima × densiflora and S. densiflora × maritima, and their parental species to four salinity concentrations for 30 days. The main objectives were to compare the performance of the hybrids with that of their parents, to distinguish the phenotypic inheritance operating in the hybrids and to analyse the relationships between the variability in the responses of the parents and the responses of their hybrids to salinity. We characterized the responses and the degree of variability for 37 foliar traits. Both hybrids presented greater salinity tolerance than their parents, showing their highest percentage of transgressive traits at both extremes of the salinity gradient. When the parental plants themselves showed a more plastic response for a given trait, there was a greater chance that their hybrid developed a transgressive behaviour for this trait. This finding supports a new focus to be applied for the artificial development of vigorous hybrid crops.

RevDate: 2018-10-31
CmpDate: 2018-10-31

Liu X, Han Y, Zhu J, et al (2018)

Will elevated atmospheric CO2 boost the growth of an invasive submerged macrophyte Cabomba caroliniana under the interference of phytoplankton?.

Environmental science and pollution research international, 25(2):1809-1821.

The growth of most submerged macrophytes is likely to be limited by the availability of carbon resource, and this is especially true for the obligatory carbon dioxide (CO2) users. A mesocosm experiment was performed to investigate the physiological, photophysiological, and biochemical responses of Cabomba caroliniana, an invasive macrophyte specie in the Lake Taihu Basin, to elevated atmospheric CO2 (1000 μmol mol-1); we also examined the possible impacts of interferences derived from the phytoplankton proliferation and its concomitant disturbances on the growth of C. caroliniana. The results demonstrated that elevated atmospheric CO2 significantly enhanced the biomass, relative growth rate, and photosynthate accumulation of C. caroliniana. C. caroliniana exposed to elevated atmospheric CO2 exhibited a higher relative maximum electron transport rate and photosynthetic efficiency, compared to those exposed to ambient atmospheric CO2. However, the positive effects of elevated atmospheric CO2 on C. caroliniana were gradually compromised as time went by, and the down-regulations of the relative growth rate (RGR) and photosynthetic activity were coupled with phytoplankton proliferation under elevated atmospheric CO2. This study demonstrated that the growth of C. caroliniana under the phytoplankton interference can be greatly affected, directly and indirectly, by the increasing atmospheric CO2.

RevDate: 2018-10-31
CmpDate: 2018-10-31

Gentès S, Taupiac J, Colin Y, et al (2017)

Bacterial periphytic communities related to mercury methylation within aquatic plant roots from a temperate freshwater lake (South-Western France).

Environmental science and pollution research international, 24(23):19223-19233.

Macrophyte floating roots are considered as hotspots for methylmercury (MeHg) production in aquatic ecosystems through microbial activity. Nevertheless, very little is known about periphyton bacterial communities and mercury (Hg) methylators in such ecological niches. The ability to methylate inorganic Hg is broadly distributed among prokaryotes; however, sulfate-reducers have been reported to be the most important MeHg producers in macrophyte floating roots. In the present work, the periphyton bacterial communities colonizing Ludwigia sp. floating roots were investigated through molecular methods. Among the 244 clones investigated, anaerobic microorganisms associated with the sulfur biogeochemical cycle were identified. Notably, members of the sulfur-oxidizing prokaryotes and the anoxygenic, purple non-sulfur bacteria (Rhodobacteraceae, Comamonadaceae, Rhodocyclaceae, Hyphomicrobiaceae) and the sulfate reducers (Desulfobacteraceae, Syntrophobacteraceae, and Desulfobulbaceae) were detected. In addition, 15 sulfate-reducing strains related to the Desulfovibrionaceae family were isolated and their Hg-methylation capacity was tested using a biosensor. The overall results confirmed that Hg methylation is a strain-specific process since the four strains identified as new Hg-methylators were closely related to non-methylating isolates. This study highlights the potential involvement of periphytic bacteria in Hg methylation when favorable environmental conditions are present in such ecological micro-niches.

RevDate: 2018-10-31
CmpDate: 2018-10-31

Jones ML, Ramoneda J, Rivett DW, et al (2017)

Biotic resistance shapes the influence of propagule pressure on invasion success in bacterial communities.

Ecology, 98(7):1743-1749.

The number of invaders and the timing of invasion are recognized as key determinants of successful invasions. Despite the recognized importance of "propagule pressure," invasion ecology has largely focused on how characteristics of the native community confer invasion resistance. We simultaneously manipulated community composition and invader propagule pressure in microcosm communities of freshwater bacteria. We show that high propagule pressures can be necessary to establish an invader population, but that the influence of propagule pressure depends on the composition of the resident species. In particular, the number of individuals invading was most important to invasion success when one of the species in a resident community is a strong competitor against other species. By contrast, the timing of invasion was most important when communities had lower growth rates. The results suggest that the importance of propagule pressure varies both between communities and within the same community over time, and therefore have implications for the way we understand the relationship between biotic resistance and invasion success.

RevDate: 2018-10-30

Richter A, Gándara AM, Silva F, et al (2018)

The alien slipper limpet Crepipatella dilatata (Lamarck, 1819) in northern Spain: A multidisciplinary approach to its taxonomic identification and invasive biology.

PloS one, 13(10):e0205739 pii:PONE-D-18-00094.

The slipper limpet Crepipatella dilatata, native to Chile and Argentina, was introduced in Spain in 2005. The species was thought to inhabit the region of Rias Bajas, yet recently, putative C. dilatata populations have been documented on the coast of north-central Spain and in the Ebro Delta of the Spanish Mediterranean. Here we undertook a multidisciplinary approach to study the invasion biology of this species. Specifically, two geographically distant populations, one being a successfully established population from O Grove and the other a declining population from Gijon, were studied over the course of four years. Analyses of morphological and developmental traits as well as genetic information confirmed the presence of C. dilatata in these sites. The results revealed polymorphism in anatomical traits and shell shape. Shell shape polymorphism was unevenly distributed among sites and among sexes. Males were monomorphic, while females were polymorphic. Of the female morphotypes encountered, one was absent in the declining population from Gijón. Size at first female maturation and female size were greater in the declining population than in the established population. Reproductive success varied seasonally but not spatially among populations. In the established population, gregariousness was significantly greater; the size when sex changes was found to be plastic and socially controlled. The sex ratio of the declining population was female biased while in the established population the sex ratio changed during the study period from being balanced to being female biased. This change in sex ratio was probably due to higher male mortality. Molecular analyses pointed to the localities of Corral Bay in southern Chile and Puerto Madryn in southern Argentina as potential population sources. The intercontinental import of fresh mussels cultivated in Chilean farms is a likely source of this mussel in Spain. Comparison with available data of native populations of C. dilatata strongly indicate that ecophenotypic plasticity, socially controlled sex change, high gregariousness, increased nurse egg supply to viable larvae during the encapsulated developmental period, later maturation and larger female sizes altogether enhance establishment success of this non-indigenous species. Human-mediated factors like the intraregional mussel trade and transplantation are also likely secondary dispersal mechanisms favouring the spread of this organism.

RevDate: 2018-10-30

Cao Y, Xiao Y, Zhang S, et al (2018)

Simulated warming enhances biological invasion of Solidago canadensis and Bidens frondosa by increasing reproductive investment and altering flowering phenology pattern.

Scientific reports, 8(1):16073 pii:10.1038/s41598-018-34218-9.

Phenological and reproductive shifts of plants due to climate change may have important influences on population dynamics. Climate change may also affect invasive species by changing their phenology and reproduction, but few studies have explored this possibility. Here, we investigated the impact of climate change on the phenology, reproduction and invasion potential of two alien Solidago canadensis and Bidens frondosa and one native weed, Pterocypsela laciniata, all of which are in the Asteraceae family. The three species responded to simulated climate change by increasing reproductive investments and root/leaf ratio, prolonging flowering duration, and while the two alien species also displayed a mass-flowering pattern. Moreover, our experimental results indicated that the alien invasive species may have greater phenological plasticity in response to simulated warming than that of the native species (P. laciniata). As such, climate change may enhance the invasion and accelerate the invasive process of these alien plant species.

RevDate: 2018-10-30

Hedges SB, Cohen WB, Timyan J, et al (2018)

Haiti's biodiversity threatened by nearly complete loss of primary forest.

Proceedings of the National Academy of Sciences of the United States of America pii:1809753115 [Epub ahead of print].

Tropical forests hold most of Earth's biodiversity. Their continued loss through deforestation and agriculture is the main threat to species globally, more than disease, invasive species, and climate change. However, not all tropical forests have the same ability to sustain biodiversity. Those that have been disturbed by humans, including forests previously cleared and regrown (secondary growth), have lower levels of species richness compared with undisturbed (primary) forests. The difference is even greater considering extinctions that will later emanate from the disturbance (extinction debt). Here, we find that Haiti has less than 1% of its original primary forest and is therefore among the most deforested countries. Primary forest has declined over three decades inside national parks, and 42 of the 50 highest and largest mountains have lost all primary forest. Our surveys of vertebrate diversity (especially amphibians and reptiles) on mountaintops indicates that endemic species have been lost along with the loss of forest. At the current rate, Haiti will lose essentially all of its primary forest during the next two decades and is already undergoing a mass extinction of its biodiversity because of deforestation. These findings point to the need, in general, for better reporting of forest cover data of relevance to biodiversity, instead of "total forest" as defined by the United Nation's Food and Agricultural Organization. Expanded detection and monitoring of primary forest globally will improve the efficiency of conservation measures, inside and outside of protected areas.

RevDate: 2018-10-30
CmpDate: 2018-10-30

Gomez-Uchida D, Sepúlveda M, Ernst B, et al (2018)

Chile's salmon escape demands action.

Science (New York, N.Y.), 361(6405):857-858.

RevDate: 2018-10-30
CmpDate: 2018-10-30

Ardura A, Zaiko A, Morán P, et al (2017)

Epigenetic signatures of invasive status in populations of marine invertebrates.

Scientific reports, 7:42193 pii:srep42193.

Epigenetics, as a DNA signature that affects gene expression and enables rapid reaction of an organism to environmental changes, is likely involved in the process of biological invasions. DNA methylation is an epigenetic mechanism common to plants and animals for regulating gene expression. In this study we show, for the first time in any marine species, significant reduction of global methylation levels during the expansive phase of a pygmy mussel (Xenostrobus securis) recent invasion in Europe (two-year old), while in older introductions such epigenetic signature of invasion was progressively reduced. Decreased methylation was interpreted as a rapid way of increasing phenotypic plasticity that would help invasive populations to thrive. This epigenetic signature of early invasion was stronger than the expected environmental signature of environmental stress in younger populations sampled from ports, otherwise detected in a much older population (>90 year old) of the also invasive tubeworm Ficopomatus enigmaticus established in similar locations. Higher epigenetic than genetic diversity found in X. securis was confirmed from F. enigmaticus samples. As reported for introduced plants and vertebrates, epigenetic variation could compensate for relatively lower genetic variation caused by founder effects. These phenomena were compared with epigenetic mechanisms involved in metastasis, as parallel processes of community (biological invasion) and organism (cancer) invasions.

RevDate: 2018-10-29

Kujawska M, Zamudio F, Montti L, et al (2018)

Effects of Landscape Structure on Medicinal Plant Richness in Home Gardens: Evidence for the Environmental Scarcity Compensation Hypothesis.

Economic botany, 72(2):150-165.

Our research involves of how Paraguayan migrants who are living in Misiones, Argentina, manage medicinal plants in home gardens, and how this practice can be related to the landscape. We examine the relationship between the richness of home garden medicinal plants and landscape variables (e.g., distance to the forest) by applying PLS analysis, which combines principal component analysis with linear regression. We surveyed 60 home gardens localized in a rural area, and we characterized the surrounding landscape with geospatial tools. Paraguayans' home gardens are extremely diverse sites (total of 136 medicinal species), where both native (82) and introduced species (50) are managed. People who live close to the native forest or mixed use areas (e.g., farms, secondary vegetation) tend to possess less native plants in their gardens because they are available nearby. While gardeners, who live in proximity to tree crops (e.g., pine plantations), have reduced access to wild medicinal resources; therefore, their effort is concentrated on maintaining native plants. These results reflect a relationship between accessibility to medicinal plants in the landscape and the management practices in the home gardens, a neglected driver in explaining the richness and composition of the medicinal plants in home gardens so far. Thus, we contributed evidence in support of the environmental scarcity compensation hypothesis. Finally, our study supports the idea that home gardens appear to function as a springboard for plant domestication.

RevDate: 2018-10-29
CmpDate: 2018-10-29

Xie BH, GX Han (2018)

Control of invasive Spartina alterniflora: A review.

Ying yong sheng tai xue bao = The journal of applied ecology, 29(10):3464-3476.

Spartina alterniflora has important ecological functions in its original place, such as bank protection and land reclamation, but often has negative impacts on the local ecosystem after it is introduced into new areas. This species is often considered as an invasive one. The invasion and control of S. alterniflora have caused a great concern. We reviewed the latest research progresses in the prevention and control of S. alterniflora from six different perspectives, including physical control, chemical control, biological control, biological substitution control, integrated control, and control strategies. The theoretical basis, technical details, control effect and environmental impact of the six kinds of control technologies were analyzed. We pointed out the shortcomings of existing control technologies and proposed some suggestions such as targeted control of different ecological risk zones.

RevDate: 2018-10-29
CmpDate: 2018-10-29

Goodell K, IM Parker (2017)

Invasion of a dominant floral resource: effects on the floral community and pollination of native plants.

Ecology, 98(1):57-69.

Through competition for pollinators, invasive plants may suppress native flora. Community-level studies provide an integrative assessment of invasion impacts and insights into factors that influence the vulnerability of different native species. We investigated effects of the nonnative herb Lythrum salicaria on pollination of native species in 14 fens of the eastern United States. We compared visitors per flower for 122 native plant species in invaded and uninvaded fens and incorporated a landscape-scale experiment, removing L. salicaria flowers from three of the invaded fens. Total flower densities were more than three times higher in invaded than uninvaded or removal sites when L. salicaria was blooming. Despite an increase in number of visitors with number of flowers per area, visitors per native flower declined with increasing numbers of flowers. Therefore, L. salicaria invasion depressed visitation to native flowers. In removal sites, visitation to native flowers was similar to uninvaded sites, confirming the observational results and also suggesting that invasion had not generated a persistent build-up of visitor populations. To study species-level impacts, we examined effects of invasion on visitors per flower for the 36 plant species flowering in both invaded and uninvaded fens. On average, the effect of invasion represented about a 20% reduction in visits per flower. We measured the influence of plant traits on vulnerability to L. salicaria invasion using meta-analysis. Bilaterally symmetrical flowers experienced stronger impacts on visitation, and similarity in flower color to L. salicaria weakly intensified competition with the invader for visitors. Finally, we assessed the reproductive consequences of competition with the invader in a dominant flowering shrub, Dasiphora fruticosa. Despite the negative effect of invasion on pollinator visitation in this species, pollen limitation of seed production was not stronger in invaded than in uninvaded sites, suggesting little impact of competition for pollinators on its population demography. Negative effects on pollination of native plants by this copiously flowering invader appeared to be mediated by increases in total flower density that were not matched by increases in pollinator density. The strength of impact was modulated across native species by their floral traits and reproductive ecology.

RevDate: 2018-10-28

Eyer PA, Matsuura K, Vargo EL, et al (2018)

Inbreeding tolerance as a pre-adapted trait for invasion success in the invasive ant Brachyponera chinensis.

Molecular ecology [Epub ahead of print].

Identifying traits that facilitate species introductions and successful invasions of ecosystems represents a key issue in ecology. Following their establishment into new environments, many non-native species exhibit phenotypic plasticity with post-introduction changes in behavior, morphology or life history traits that allow them to overcome the presumed loss of genetic diversity resulting in inbreeding and reduced adaptive potential. Here we present a unique strategy in the invasive ant Brachyponera chinensis (Emery), in which inbreeding tolerance is a pre-adapted trait for invasion success, allowing this ant to cope with genetic depletion following a genetic bottleneck. We report for the first time that inbreeding is not a consequence of the founder effect following introduction, but it is due to mating between sister queens and their brothers that pre-exists in native populations which may have helped it circumvent the cost of invasion. We show that a genetic bottleneck does not affect the genetic diversity or the level of heterozygosity within colonies and suggest that generations of sibmating in native populations may have reduced inbreeding depression through purifying selection of deleterious alleles. This work highlights how a unique life history may pre-adapt some species for biological invasions. This article is protected by copyright. All rights reserved.

RevDate: 2018-10-28

Haram LE, Kinney KA, Sotka EE, et al (2018)

Mixed effects of an introduced ecosystem engineer on the foraging behavior and habitat selection of predators.

Ecology [Epub ahead of print].

Invasive ecosystem engineers both positively and negatively affect their recipient ecosystems by generating novel habitats. Many studies have focused on alterations to ecosystem properties and to native species diversity and abundance caused by invasive engineers. However, relatively few studies have documented the extent to which behaviors of native species are affected. The red seaweed Gracilaria vermiculophylla (Rhodophyta) invaded estuaries of the southeastern United States within the last few decades and now provides abundant aboveground vegetative cover on intertidal mudflats that were historically devoid of seaweeds. We hypothesized that G. vermiculophylla would affect the foraging behavior of native shorebirds positively for birds that target seaweed-associated invertebrates or negatively for birds that target prey on or within the sediment now covered with seaweed. Visual surveys of mudflats >1 ha in size revealed that more shorebirds occurred on mudflats with G. vermiculophylla relative to mudflats without G. vermiculophylla. This increased density was consistent across 7 of 8 species, with the one exception being the semipalmated plover Charadrius semipalmatus. A regression-based analysis indicated that while algal presence predicted shorebird density, densities of some bird species depended on sediment composition and infaunal invertebrate densities. At smaller spatial scales (200 m2 and <1 m2), experimental removals and additions of G. vermiculophylla and focal observations showed strong variation in behavioral response to G. vermiculophylla among bird species. Birds preferentially foraged in bare mud (e.g., C. semipalmatus), in G. vermiculophylla (e.g., Arenaria interpres), or displayed no preference for either habitat (e.g., Tringa semipalmata). Thus, while the presence of the invasive ecosystem engineer on a mudflat appeared to attract greater numbers of these predators, shorebird species differed in their behavioral responses at the smaller spatial scales that affect their foraging. Our research illuminates the need to account for species identity, individual behavior, and scale when predicting the impacts of invasive species on native communities.

RevDate: 2018-10-27

Rueckert S, Glasinovich N, Diez ME, et al (2018)

Morphology and molecular systematic of marine gregarines (Apicomplexa) from Southwestern Atlantic spionid polychaetes.

Journal of invertebrate pathology pii:S0022-2011(18)30125-3 [Epub ahead of print].

Gregarines are a common group of parasites that infect the intestines of marine invertebrates, and particularly polychaetes. Here, we describe for the first time four gregarine species that inhabit the intestines of three spionid species: Dipolydora cf. flava, Spio quadrisetosa and Boccardia proboscidea from the Patagonian coast, Argentina, using light and scanning electron microscopy and molecular phylogenetic analyses of small subunit (SSU) rDNA sequences. Even though the spionid species thrive in the same environments, our results showed a high host specificity of the gregarine species. Selenidium cf. axiferens and Polyrhabdina aff. polydorae were both identified from the intestine of D. cf. flava. The new species, Polyrhabdina madrynense sp. n. and Selenidium patagonica sp. n., were described from the intestines of S. quadrisetosa and the invasive species B. proboscidea, respectively. All specimens of D. cf. flava and S. quadrisetosa were infected by gregarines (P = 100%), recording the highest mean intensity values of infection (MI = 80; 60 respectively), in contrast to B. proboscidea (P = 60%; MI = 38). We associated this finding with the recent invasion of this host. It is expected that in the future, an increase of its population density might favour a rising intensity of this gregarine infection.

RevDate: 2018-10-27

Wang S, Wang C, Wang S, et al (2018)

Big data analysis for evaluating bioinvasion risk.

BMC bioinformatics, 19(Suppl 9):287 pii:10.1186/s12859-018-2272-5.

BACKGROUND: Global maritime trade plays an important role in the modern transportation industry. It brings significant economic profit along with bioinvasion risk. Species translocate and establish in a non-native area through ballast water and biofouling. Aiming at aquatic bioinvasion issue, people proposed various suggestions for bioinvasion management. Nonetheless, these suggestions only focus on the chance of a port been affected but ignore the port's ability to further spread the invaded species.

RESULTS: To tackle the issues of the existing work, we propose a biosecurity triggering mechanism, where the bioinvasion risk of a port is estimated according to both the invaded risk of a port and its power of being a stepping-stone. To compute the invaded risk, we utilize the automatic identification system data, the ballast water data and marine environmental data. According to the invaded risk of ports, we construct a species invasion network (SIN). The incoming bioinvasion risk is derived from invaded risk data while the invasion risk spreading capability of each port is evaluated by s-core decomposition of SIN.

CONCLUSIONS: We illustrate 100 ports in the world that have the highest bioinvasion risk when the invaded risk and stepping-stone bioinvasion risk are equally treated. There are two bioinvasion risk intensive regions, namely the Western Europe (including the Western European margin and the Mediterranean) and the Asia-Pacific, which are just the region with a high growth rate of non-indigenous species and the area that has been identified as a source for many of non-indigenous species discovered elsewhere (especially the Asian clam, which is assumed to be the most invasive species worldwide).

RevDate: 2018-10-27

Freedman MG, Miller RH, HS Rogers (2018)

Landscape-level bird loss increases the prevalence of honeydew-producing insects and non-native ants.

Oecologia pii:10.1007/s00442-018-4273-5 [Epub ahead of print].

Bird exclusion experiments consistently show that birds exhibit strong top-down control of arthropods, including ants and the honeydew-producing insects (HPIs) that they tend. However, it remains unclear whether the results of these small-scale bird exclosure experiments can be extrapolated to larger spatial scales. In this study, we use a natural bird removal experiment to compare the prevalence of ants and HPIs between Guam, an island whose bird community has been extirpated since the 1980s due to the introduction of the brown tree snake, and two nearby islands (Rota and Saipan) that have more intact bird assemblages. Consistent with smaller-scale bird exclosure experiments, we show that (1) forest trees from Guam are significantly more likely to host HPIs than trees from Saipan and (2) ants are nearly four times as abundant on Guam than on both Saipan and Rota. The prevalence of HPIs varied slightly based on tree species identity, although these effects were not as strong as island-level effects associated with bird loss. Ant community composition differed between Guam and the other two islands. These results corroborate past observational studies showing increased spider densities on Guam and suggest that trophic changes associated with landscape-level bird extirpation may also involve alterations in the abundance of ants and HPIs. This study also provides a clear example of the strong indirect effects that invasive species can have on natural food webs.

RevDate: 2018-10-26

Lago M, Boteler B, Rouillard J, et al (2018)

Introducing the H2020 AQUACROSS project: Knowledge, Assessment, and Management for AQUAtic Biodiversity and Ecosystem Services aCROSS EU policies.

The Science of the total environment, 652:320-329 pii:S0048-9697(18)33949-4 [Epub ahead of print].

The AQUACROSS project was an unprecedented effort to unify policy concepts, knowledge, and management of freshwater, coastal, and marine ecosystems to support the cost-effective achievement of the targets set by the EU Biodiversity Strategy to 2020. AQUACROSS aimed to support EU efforts to enhance the resilience and stop the loss of biodiversity of aquatic ecosystems as well as to ensure the ongoing and future provision of aquatic ecosystem services. The project focused on advancing the knowledge base and application of Ecosystem-Based Management. Through elaboration of eight diverse case studies in freshwater and marine and estuarine aquatic ecosystem across Europe covering a range of environmental management problems including, eutrophication, sustainable fisheries as well as invasive alien species AQUACROSS demonstrated the application of a common framework to establish cost-effective measures and integrated Ecosystem-Based Management practices. AQUACROSS analysed the EU policy framework (i.e. goals, concepts, time frames) for aquatic ecosystems and built on knowledge stemming from different sources (i.e. WISE, BISE, Member State reporting within different policy processes, modelling) to develop innovative management tools, concepts, and business models (i.e. indicators, maps, ecosystem assessments, participatory approaches, mechanisms for promoting the delivery of ecosystem services) for aquatic ecosystems at various scales of space and time and relevant to different ecosystem types.

RevDate: 2018-10-26

Wyckhuys KAG, Wongtiem P, Rauf A, et al (2018)

Continental-scale suppression of an invasive pest by a host-specific parasitoid underlines both environmental and economic benefits of arthropod biological control.

PeerJ, 6:e5796 pii:5796.

Biological control, a globally-important ecosystem service, can provide long-term and broad-scale suppression of invasive pests, weeds and pathogens in natural, urban and agricultural environments. Following (few) historic cases that led to sizeable environmental up-sets, the discipline of arthropod biological control has-over the past decades-evolved and matured. Now, by deliberately taking into account the ecological risks associated with the planned introduction of insect natural enemies, immense environmental and societal benefits can be gained. In this study, we document and analyze a successful case of biological control against the cassava mealybug, Phenacoccus manihoti (Hemiptera: Pseudococcidae) which invaded Southeast Asia in 2008, where it caused substantial crop losses and triggered two- to three-fold surges in agricultural commodity prices. In 2009, the host-specific parasitoid Anagyrus lopezi (Hymenoptera: Encyrtidae) was released in Thailand and subsequently introduced into neighboring Asian countries. Drawing upon continental-scale insect surveys, multi-year population studies and (field-level) experimental assays, we show how A. lopezi attained intermediate to high parasitism rates across diverse agro-ecological contexts. Driving mealybug populations below non-damaging levels over a broad geographical area, A. lopezi allowed yield recoveries up to 10.0 t/ha and provided biological control services worth several hundred dollars per ha (at local farm-gate prices) in Asia's four-million ha cassava crop. Our work provides lessons to invasion science and crop protection worldwide. Furthermore, it accentuates the importance of scientifically-guided biological control for insect pest management, and highlights its potentially large socio-economic benefits to agricultural sustainability in the face of a debilitating invasive pest. In times of unrelenting insect invasions, surging pesticide use and accelerating biodiversity loss across the globe, this study demonstrates how biological control-as a pure public good endeavor-constitutes a powerful, cost-effective and environmentally-responsible solution for invasive species mitigation.

RevDate: 2018-10-26

Duffy L, De Wilde L, Spellman K, et al (2018)

Resilience and Adaptation: Yukon River Watershed Contaminant Risk Indicators.

Scientifica, 2018:8421513.

River watersheds are among the most complex terrestrial features in Alaska, performing valuable ecosystem functions and providing services for human society. Rivers are vital to both estuarine and aquatic biota and play important roles in biogeochemical cycles and physical processes. The functions of watersheds have been used as vulnerability indicators for ecosystem and socioeconomic resilience. Despite a long history of human activity, the Yukon River has not received the holistic and interdisciplinary attention given to the other great American river systems. By using hypothesis-based monitoring of key watershed functions, we can gain insight to regime-shifting stresses such as fire, toxins, and invasive species development. Coupling adaptive risk management practices involving stakeholders with place-based education, especially contaminants and nutrition related, can maintain resilience within communities. The Yukon watershed provides a broadscale opportunity for communities to monitor the environment, manage resources, and contribute to stewardship policy formation. Monitoring keystone species and community activities, such as citizen science, are critical first steps to following changes to resiliency throughout the Yukon watershed. Creating a policy environment that encourages local experimentation and innovation contributes to resilience maintenance during development-imposed stress.

RevDate: 2018-10-26

Shechonge A, Ngatunga BP, Tamatamah R, et al (2018)

Losing cichlid fish biodiversity: genetic and morphological homogenization of tilapia following colonization by introduced species.

Conservation genetics (Print), 19(5):1199-1209.

Among the many negative impacts of invasive species, hybridization with indigenous species has increasingly become recognized as a major issue. However, relatively few studies have characterized the phenotypic outcomes of hybridization following biological invasions. Here we investigate the genetic and morphological consequences of stocking invasive tilapia species in two water bodies in central Tanzania. We sampled individuals from the Mindu Reservoir on the Ruvu river system, and at Kidatu on the Great Ruaha-Rufiji river system. We screened individuals at 16 microsatellite loci, and quantified morphology using geometric morphometrics and linear measurements. In both the Mindu and Kidatu systems, we identified evidence of hybridization between indigenous Wami tilapia (Oreochromis urolepis) and the introduced Nile tilapia (Oreochromis niloticus) or blue-spotted tilapia (Oreochromis leucostictus). At both sites, purebred individuals could largely be separated using geometric morphometric variables, with hybrids occupying a broad morphospace among the parental species. Our data demonstrate that the gene pools and phenotypic identity of the indigenous O. urolepis have been severely impacted by the stocking of the invasive species. Given the lack of evidence for clear commercial benefits from stocking invasive tilapia species in waters already populated by indigenous congenerics, we suggest further spread of introduced species should be undertaken with considerable caution.

RevDate: 2018-10-26

Timóteo S, O'Connor CJ, López-Núñez FA, et al (2018)

Pollination networks from natural and anthropogenic-novel communities show high structural similarity.

Oecologia pii:10.1007/s00442-018-4281-5 [Epub ahead of print].

The Anthropocene is marked by an unprecedented homogenisation of the world's biota, confronting species that never co-occurred during their evolutionary histories. Interactions established in these novel communities may affect ecosystem functioning; however, most research has focused on the impacts of a minority of aggressive invasive species, while changes inflicted by a less conspicuous majority of non-invasive alien species on community structure are still poorly understood. This information is critical to guide conservation strategies, and instrumental to advance ecological theory, particularly to understand how non-native species integrate in recipient communities and affect the interactions of native species. We evaluated how the structure of 50 published pollination networks changes with the proportion of alien plant species and found that network structure is largely unaffected. Although some communities were heavily invaded, the proportion of alien plant species was relatively low (mean = 10%; max. = 38%). We further characterized the pollination network in a botanic garden with a plant community dominated by non-invasive alien species (85%). We show that the structure of this novel community is also not markedly different from native-dominated communities. Plant-pollinator interactions revealed no obvious differences regarding plant origin (native vs. alien) or the native bioregion of the introduced plants. This overall similarity between native and alien plants is likely driven by the contrasting patterns of invasive plants (promoting generalism), and non-invasive aliens, suggested here to promote specialization.

RevDate: 2018-10-26

Qazi SS, Lombardo DA, MM Abou-Zaid (2018)

A Metabolomic and HPLC-MS/MS Analysis of the Foliar Phenolics, Flavonoids and Coumarins of the Fraxinus Species Resistant and Susceptible to Emerald Ash Borer.

Molecules (Basel, Switzerland), 23(11): pii:molecules23112734.

The Emerald Ash Borer (EAB), Agrilus planipennis, Fairmaire, an Asian invasive alien buprestid has devastated tens of millions of ash trees (Fraxinus spp.) in North America. Foliar phytochemicals of the genus Fraxinus (Oleaceae): Fraxinus pennsylvanica (Green ash), F. americana (White ash), F. profunda (Bush) Bush. (Pumpkin ash), F. quadrangulata Michx. (Blue ash), F. nigra Marsh. (Black ash) and F. mandshurica (Manchurian ash) were investigated using HPLC-MS/MS and untargeted metabolomics. HPLC-MS/MS help identified 26 compounds, including phenolics, flavonoids and coumarins in varying amounts. Hydroxycoumarins, esculetin, esculin, fraxetin, fraxin, fraxidin and scopoletin were isolated from blue, black and Manchurian ashes. High-throughput metabolomics revealed 35 metabolites, including terpenes, secoiridoids and lignans. Metabolomic profiling indicated several upregulated putative compounds from Manchurian ash, especially fraxinol, ligstroside, oleuropin, matairesinol, pinoresinol glucoside, 8-hydroxypinoresinol-4-glucoside, verbenalin, hydroxytyrosol-1-O-glucoside, totarol and ar-artemisene. Further, dicyclomine, aphidicolin, parthenolide, famciclovir, ar-turmerone and myriocin were identified upregulated in blue ash. Principal component analysis demonstrated a clear separation between Manchurian and blue ashes from black, green, white and pumpkin ashes. The presence of defensive compounds upregulated in Manchurian ash, suggests their potential role in providing constitutive resistance to EAB, and reflects its co-evolutionary history with A. planipennis, where they appear to coexist in their native habitats.

RevDate: 2018-10-25

Caruso N, Valenzuela AEJ, Burdett CL, et al (2018)

Summer habitat use and activity patterns of wild boar Sus scrofa in rangelands of central Argentina.

PloS one, 13(10):e0206513 pii:PONE-D-18-16021.

Biological invasions are one of the main components of human-caused global change and their negative impact on invaded ecosystems have long been recognized. Invasive mammals, in particular, can threaten native biodiversity and cause economic impacts in the region where they are introduced, often through a wide range of conflicts with humans. Although the wild boar, Sus scrofa, is considered by the IUCN as one of the 100 invasive species most damaging to biodiversity in the world, in Argentina there have only been a few studies focused on its ecology with most of them conducted in protected areas. In this study, we evaluated the effect of several factors related with human disturbance, landscape composition, degree of fragmentation and the presence of a potential competitor and a predator on the habitat use of wild boar using data from camera traps and site-occupancy modeling. Additionally, we described the daily activity pattern of the species and we studied the level of overlap with both a potential competitor and a predator. The sampling effort totaled 7,054 camera trap days. Farm density, proportion of shrubland and proportion of grassland with bushes were the detection variables included in the most supported model whereas proportion of grassland and capture rate of the Pampas fox Lycalopex gymnocercus were the occupancy variables included in the most supported model. However, the proportion of grassland was the only variable that showed statistically significant support in the averaged model, indicating that habitat use of wild boar in this area was significantly negatively affected by the level of grass cover. Wild boars were mostly nocturnal, with more activity between 21:00 and 3:00 and a peak around midnight. Wild boars showed a high level of overlap with the activity pattern of the Pampas fox and a low overlap with the activity pattern of the puma Puma concolor. Despite wild boar being introduced in Argentina a few decades ago, this study is the first landscape-scale research carried out in an agricultural landscape in Argentina and the first one based on camera-trapping data. Our study contributes valuable information that could be used to design strategies to reduce wild boar population or to minimize the damage caused by this invasive species in Argentina.

RevDate: 2018-10-23

Cui J, Zhu SY, Gao Y, et al (2018)

Comparative Transcriptome Analysis of Megacopta cribraria (Hemiptera: Plataspidae) in Response to High-Temperature Stress.

Journal of economic entomology pii:5142323 [Epub ahead of print].

Kudzu bug, Megacopta cribraria (Fabricius), is mainly distributed in southern China and has been considered an invasive species in the southeastern United States. Megacopta cribraria is a soybean pest with high-temperature resistance, but the molecular mechanisms underlying its thermal adaptation are largely unknown. Here, we performed comparative transcriptome analysis to unravel the molecular response of M. cribraria toward high-temperature stress. Following RNA-seq, we identified 93,959 assembled unigenes, 14,073 of which were annotated in M. cribraria transcriptome libraries. In addition, 127 differentially expressed unigenes (DEGs) were detected, 88 of them were significantly upregulated, whereas the remaining 39 genes were significantly downregulated. Functional classification revealed that the pathways of metabolic process, cellular processes, and single-organism processes were considered to be significantly enriched. In the COG classification, DEGs were mainly localized into O: post-translational modification, protein turnover, chaperone. Moreover, protein processing in endoplasmic reticulum and linoleic acid metabolism were significantly enriched among the 38 KEGG pathways. Further gene annotation analysis indicated that nine heat shock protein-related genes were significantly upregulated. Finally, five HSP DEGs were selected for real-time quantitative polymerase chain reaction validation and demonstrated a similar upregulation trend with RNA-seq expression profiles. Taken altogether, these findings provide new insights into the molecular mechanisms of thermal adaptation in M. cribraria.

RevDate: 2018-10-23

Brown PMJ, Roy DB, Harrower C, et al (2018)

Spread of a model invasive alien species, the harlequin ladybird Harmonia axyridis in Britain and Ireland.

Scientific data, 5:180239 pii:sdata2018239.

Invasive alien species are widely recognized as one of the main threats to global biodiversity. Rapid flow of information on the occurrence of invasive alien species is critical to underpin effective action. Citizen science, i.e. the involvement of volunteers in science, provides an opportunity to improve the information available on invasive alien species. Here we describe the dataset created via a citizen science approach to track the spread of a well-studied invasive alien species, the harlequin ladybird Harmonia axyridis (Coleoptera: Coccinellidae) in Britain and Ireland. This dataset comprises 48 510 verified and validated spatio-temporal records of the occurrence of H. axyridis in Britain and Ireland, from first arrival in 2003, to the end of 2016. A clear and rapid spread of the species within Britain and Ireland is evident. A major reuse value of the dataset is in modelling the spread of an invasive species and applying this to other potential invasive alien species in order to predict and prevent their further spread.

RevDate: 2018-10-23

Hu L, Wu X, Li H, et al (2018)

An effector, BxSapB1, induces cell death and contributes to virulence in the pine wood nematode Bursaphelenchus xylophilus.

Molecular plant-microbe interactions : MPMI [Epub ahead of print].

The pine wood nematode (PWN) Bursaphelenchus xylophilus has caused serious damage to pine forests in China. Effectors secreted by phytonematodes play a role in host infection. We identified and characterized an effector, BxSapB1, based on the B. xylophilus transcriptome at the early stages of infection and the transient expression of proteins in Nicotiana benthamiana. BxSapB1 triggered cell death in N. benthamiana when secreted into the apoplast, and this effect was independent of N. benthamiana brassinosteroid-insensitive 1-associated kinase 1 (NbBAK1) and suppressor of BIR1-1 (NbSOBIR1). The signal peptide of BxSapB1 was proven to be functional in yeast using the yeast signal sequence trap system, and BxSapB1 was strongly expressed in the subventral gland cells of B. xylophilus, as revealed by in situ hybridization. In addition, based on local BLAST analysis, the BxSapB1 showed 100% identity to BUX.s00139.62, which was identified from the B. xylophilus secretome during Pinus thunbergii infection. BxSapB1 was upregulated in a highly virulent strain and downregulated in a weakly virulent strain of PWN at the early stages of infection. RNA interference assays showed that silencing BxSapB1 resulted in decreased expression of pathogenesis related genes (PtPR-1b, PtPR-3 and PtPR-5), as well as delayed onset of symptoms in P. thunbergii infected by B. xylophilus. The combined data suggest that BxSapB1 can trigger cell death in N. benthamiana, and that it contributes to the virulence in B. xylophilus during parasitic interaction.

RevDate: 2018-10-23

James Harris D, Halajian A, Santos JL, et al (2018)

Diversity of haemoprotozoan parasites infecting the wildlife of South Africa.

Folia parasitologica, 65:.

Tissue samples from wildlife from South Africa were opportunistically collected and screened for haemoprotozoan parasites using nonspecific PCR primers. Samples of 127 individuals were tested, comprising over 50 different species. Haemogregarines were the most commonly identified parasites, but sarcocystids and piroplasmids were also detected. Phylogenetic analyses estimated from the 18S rDNA marker highlighted the occurrence of several novel parasite forms and the detection of parasites in novel hosts. Phylogenetic relationships, which have been recently reviewed, appear to be much more complex than previously considered. Our study highlights the high diversity of parasites circulating in wildlife in this biodiverse region, and the need for further studies to resolve taxonomic issues.

RevDate: 2018-10-23

Derham TT, Duncan RP, Johnson CN, et al (2018)

Hope and caution: rewilding to mitigate the impacts of biological invasions.

Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 373(1761): pii:rstb.2018.0127.

Rewilding is a novel approach to ecological restoration. Trophic rewilding in particular aims to reinstate ecological functions, especially trophic interactions, through the introduction of animals. We consider the potential for trophic rewilding to address biological invasions. In this broad review, we note some of the important conceptual and ethical foundations of rewilding, including a focus on ecosystem function rather than composition, reliance on animal agency, and an appeal to an ethic of coexistence. Second, we use theory from invasion biology to highlight pathways by which rewilding might prevent or mitigate the impacts of an invasion, including increasing biotic resistance. Third, we use a series of case studies to illustrate how reintroductions can mitigate the impacts of invasions. These include reintroductions and positive management of carnivores and herbivores including European pine martens (Martes martes), Eurasian otters (Lutra lutra), dingoes (Canis dingo), Tasmanian devils (Sarcophilus harrisii) and tule elk (Cervus canadensis nannodes). Fourth, we consider the risk that rewilding may enable a biological invasion or aggravate its impacts. Lastly, we highlight lessons that rewilding science might take from invasion biology.This article is part of the theme issue 'Trophic rewilding: consequences for ecosystems under global change'.

RevDate: 2018-10-23

Tanentzap AJ, BR Smith (2018)

Unintentional rewilding: lessons for trophic rewilding from other forms of species introductions.

Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 373(1761): pii:rstb.2017.0445.

Trophic rewilding involves adding species into ecosystems to restore extinct, top-down interactions, but limited quantitative data have prevented a systematic attempt to quantify its outcomes. Here, we exploit species introductions that have occurred for purposes other than restoration to inform trophic rewilding. We compiled 51 studies with 158 different responses of lower trophic levels to a species introduction that restored an extinct interaction, whether it intended to do so or not. Unintentional introductions were compared with checklists of extinct animals to identify potential analogues. Using the latest meta-analysis techniques, we found that the few cases of intentional rewilding had similar effects to unintentional rewilding, though there were large taxonomic and geographical biases. We also tested predictions from studies on trophic cascades about the factors that should influence rewilding. Unintentional rewilding was stronger where introduced consumers were non-invasive, but there was no effect of time that compared sites differed in introduction status, latitude or coevolution of responses with a taxonomically related analogue. Our study now shows that rewilding can reinstate extinct trophic interactions and highlights remaining data gaps that need closure to restore ecosystems across larger scales than has been previously possible.This article is part of the theme issue 'Trophic rewilding: consequences for ecosystems under global change'.

RevDate: 2018-10-22

Yessoufou K, Bezeng SB, Gaoue O, et al (2018)

Phylogenetically diverse native systems are more resistant to invasive plant species on Robben Island, South Africa.

Genome [Epub ahead of print].

Alien invasive species are problematic both economically and ecologically, particularly on islands. As such, understanding how they interact with their environment is necessary to inform invasive species management. Here, we ask the following questions: What are the main functional traits that correlate with invasion success of alien plants on Robben Island? How does phylogenetic structure shape biotic interactions on the island? Using multiple approaches to explore these questions, we found that alien invasive species flower later during the year and for longer period, although flowering phenology was sensitive to alternative starting date. Additionally, we observed that alien invasive species are mostly abiotically pollinated and are generally hermaphroditic whilst their native counterparts rely on biotic pollinators, flower earlier and are generally dioecious, suggesting that alien invasive and native species use different ecological niches. Furthermore, we found a facilitative interaction between an alien invasive legume and other invasive plants as predicted by the invasional meltdown hypothesis, but this does not influence the phylogenetic structure of plant communities. Finally, phylogenetically diverse set of native species are less receptive to alien invasive species. Collectively, our findings reveal how biotic interactions and phylogenetic relatedness structure alien invasive-native co-existence.

RevDate: 2018-10-22

Hallman GJ, Wang L, Demirbas Uzel G, et al (2018)

Comparison of Populations of Ceratitis capitata (Diptera: Tephritidae) from Three Continents for Susceptibility to Cold Phytosanitary Treatment and Implications for Generic Cold Treatments.

Journal of economic entomology pii:5139632 [Epub ahead of print].

The Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), is arguably the most significant and studied quarantine pest of fresh fruits. There is well over a century of research observations on its response to cold, first as it pertains to shipment of fruits using cold temperatures to preserve fruit quality and how that may aid the survival and distribution of the pest, and then the use of colder temperatures to kill the pest in fruit shipments. Cold tolerance at 1.1°C in three populations of C. capitata generally increased as the insect developed; therefore, the third instar is the most tolerant of the stages that are found in fruit. The three populations did not differ in cold tolerance, indicating that cold phytosanitary treatments against this pest can be harmonized regardless of country of origin of marketed fruit hosts. This study facilitated the approval of some cold treatment schedules for the International Plant Protection Convention treatment manual that were being held up by concerns of possible differences in cold tolerance among C. capitata populations from different countries and points toward the possibility of generic, broadly applicable phytosanitary cold treatments. Most larvae found alive after 9 d of cold treatment did not pupariate and fewer still emerged as adults, indicating that acute larval mortality need not always be the objective of a cold phytosanitary treatment to be efficacious in preventing the establishment of invasive species.

RevDate: 2018-10-24

Lehnert SJ, DiBacco C, Jeffery NW, et al (2018)

Temporal dynamics of genetic clines of invasive European green crab (Carcinus maenas) in eastern North America.

Evolutionary applications, 11(9):1656-1670 pii:EVA12657.

Two genetically distinct lineages of European green crabs (Carcinus maenas) were independently introduced to eastern North America, the first in the early 19th century and the second in the late 20th century. These lineages first came into secondary contact in southeastern Nova Scotia, Canada (NS), where they hybridized, producing latitudinal genetic clines. Previous studies have documented a persistent southward shift in the clines of different marker types, consistent with existing dispersal and recruitment pathways. We evaluated current clinal structure by quantifying the distribution of lineages and fine-scale hybridization patterns across the eastern North American range (25 locations, ~39 to 49°N) using informative single nucleotide polymorphisms (SNPs; n = 96). In addition, temporal changes in the genetic clines were evaluated using mitochondrial DNA and microsatellite loci (n = 9-11) over a 15-year period (2000-2015). Clinal structure was consistent with prior work demonstrating the existence of both northern and southern lineages with a hybrid zone occurring between southern New Brunswick (NB) and southern NS. Extensive later generation hybrids were detected in this region and in southeastern Newfoundland. Temporal genetic analysis confirmed the southward progression of clines over time; however, the rate of this progression was slower than predicted by forecasting models, and current clines for all marker types deviated significantly from these predictions. Our results suggest that neutral and selective processes contribute to cline dynamics, and ultimately, highlight how selection, hybridization, and dispersal can collectively influence invasion success.

RevDate: 2018-10-24

Diedericks G, Henriques R, von der Heyden S, et al (2018)

The ghost of introduction past: Spatial and temporal variability in the genetic diversity of invasive smallmouth bass.

Evolutionary applications, 11(9):1609-1629 pii:EVA12652.

Understanding the demographic history of introduced populations is essential for unravelling their invasive potential and adaptability to a novel environment. To this end, levels of genetic diversity within the native and invasive range of a species are often compared. Most studies, however, focus solely on contemporary samples, relying heavily on the premise that the historic population structure within the native range has been maintained over time. Here, we assess this assumption by conducting a three-way comparison of the genetic diversity of native (historic and contemporary) and invasive (contemporary) smallmouth bass (Micropterus dolomieu) populations. Analyses of a total of 572 M. dolomieu samples, representing the contemporary invasive South African range, contemporary and historical native USA range (dating back to the 1930s when these fish were first introduced into South Africa), revealed that the historical native range had higher genetic diversity levels when compared to both contemporary native and invasive ranges. These results suggest that both contemporary populations experienced a recent genetic bottleneck. Furthermore, the invasive range displayed significant population structure, whereas both historical and contemporary native US populations revealed higher levels of admixture. Comparison of contemporary and historical samples showed both a historic introduction of M. dolomieu and a more recent introduction, thereby demonstrating that undocumented introductions of this species have occurred. Although multiple introductions might have contributed to the high levels of genetic diversity in the invaded range, we discuss alternative factors that may have been responsible for the elevated levels of genetic diversity and highlight the importance of incorporating historic specimens into demographic analyses.

RevDate: 2018-10-24

Tang Q, Low GW, Lim JY, et al (2018)

Human activities and landscape features interact to closely define the distribution and dispersal of an urban commensal.

Evolutionary applications, 11(9):1598-1608 pii:EVA12650.

The rock pigeon, Columba livia, is a cosmopolitan human commensal, domesticated thousands of years ago. However, the human-mediated factors governing its distribution and dispersal are not well understood. In this study, we performed (a) hierarchical distance sampling on ~400 island-wide point transects, (b) a population genomic inquiry based on ~7,000 SNPs from almost 150 individuals, and (c) landscape genomic analyses on the basis of extensive ecological and socio-economic databases to characterize the distribution and dispersal patterns of rock pigeons across Singapore. Our distance sampling results indicated that the volume of intentional "mercy feeding" and availability of high-rise buildings are the most reliable predictors of high pigeon densities in Singapore. Genomic analyses demonstrated that rock pigeons in Singapore form a single population possibly derived from rapid expansion from a genetically homogenous group of founder individuals. In specific, rock pigeons in Singapore lack sex-biased dispersal and are clustered with a genetic patch size of ~3 km. Landscape genomic analyses of great precision pointed to the presence of dense trees as agents of resistance to dispersal, whereas a high road density reduces this resistance. By pinpointing a range of ecological and socio-economic variables determining the distribution and dispersal of pigeons, our study provides urban planners with the tools for optimal management of this human commensal, such as a curtailment of the practice of mercy feeding and modifications to the urban landscape to reduce pigeon density and to lower the likelihood of repopulation by dispersal.

RevDate: 2018-10-24

Guzinski J, Ballenghien M, Daguin-Thiébaut C, et al (2018)

Population genomics of the introduced and cultivated Pacific kelp Undaria pinnatifida: Marinas-not farms-drive regional connectivity and establishment in natural rocky reefs.

Evolutionary applications, 11(9):1582-1597 pii:EVA12647.

Ports and farms are well-known primary introduction hot spots for marine non-indigenous species (NIS). The extent to which these anthropogenic habitats are sustainable sources of propagules and influence the evolution of NIS in natural habitats was examined in the edible seaweed Undaria pinnatifida, native to Asia and introduced to Europe in the 1970s. Following its deliberate introduction 40 years ago along the French coast of the English Channel, this kelp is now found in three contrasting habitat types: farms, marinas and natural rocky reefs. In the light of the continuous spread of this NIS, it is imperative to better understand the processes behind its sustainable establishment in the wild. In addition, developing effective management plans to curtail the spread of U. pinnatifida requires determining how the three types of populations interact with one another. In addition to an analysis using microsatellite markers, we developed, for the first time in a kelp, a ddRAD-sequencing technique to genotype 738 individuals sampled in 11 rocky reefs, 12 marinas, and two farms located along ca. 1,000 km of coastline. As expected, the RAD-seq panel showed more power than the microsatellite panel for identifying fine-grained patterns. However, both panels demonstrated habitat-specific properties of the study populations. In particular, farms displayed very low genetic diversity and no inbreeding conversely to populations in marinas and natural rocky reefs. In addition, strong, but chaotic regional genetic structure, was revealed, consistent with human-mediated dispersal (e.g., leisure boating). We also uncovered a tight relationship between populations in rocky reefs and those in nearby marinas, but not with nearby farms, suggesting spillover from marinas into the wild. At last, a temporal survey spanning 20 generations showed that wild populations are now self-sustaining, albeit there was no evidence for local adaptation to any of the three habitats. These findings highlight that limiting the spread of U. pinnatifida requires efficient management policies that also target marinas.

RevDate: 2018-10-19

Rebelo AJ, Emsens WJ, Esler KJ, et al (2018)

Quantification of water purification in South African palmiet wetlands.

Water science and technology : a journal of the International Association on Water Pollution Research, 78(5):1199-1207.

Despite the importance of water purification to society, it is one of the more difficult wetland ecosystem services to quantify. It remains an issue in ecosystem service assessments where rapid estimates are needed, and poor-quality indicators are overused. We attempted to quantify the water purification service of South African palmiet wetlands (valley-bottom peatlands highly threatened by agriculture). First, we used an instantaneous catchment-scale mass balance sampling approach, which compared the fate of various water quality parameters over degraded and pristine sections of palmiet wetlands. We found that pristine palmiet wetlands acted as a sink for water, major cations, anions, dissolved silicon and nutrients, though there was relatively high variation in these trends. There are important limitations to this catchment-scale approach, including the fact that at this large scale there are multiple mechanisms (internal wetland processes as well as external inputs) at work that are impossible to untangle with limited data. Therefore, secondly, we performed a small field-scale field survey of a wetland fragment to corroborate the catchment-scale results. There was a reasonable level of agreement between the results of the two techniques. We conclude that it appears possible to estimate the water purification function of these valley-bottom wetlands using this catchment-scale approach.

RevDate: 2018-10-18

Damas-Moreira I, Oliveira D, Santos JL, et al (2018)

Learning from others: an invasive lizard uses social information from both conspecifics and heterospecifics.

Biology letters, 14(10): pii:rsbl.2018.0532.

Species that are able to solve novel problems through social learning from either a conspecific or a heterospecific may gain a significant advantage in new environments. We tested the ability of a highly successful invasive species, the Italian wall lizard Podarcis sicula, to solve a novel foraging task when social information was available from both a conspecific and an unfamiliar heterospecific (Podarcis bocagei). We found that Italian wall lizards that had access to social information made fewer errors, regardless of whether the demonstrator was a conspecific or a heterospecific, compared to Italian wall lizards that individually learnt the same task. We suggest that social learning could be a previously underappreciated, advantageous mechanism facilitating invasions.

RevDate: 2018-10-17

Manley M, Melzer MJ, H Spafford (2018)

Oviposition Preferences and Behavior of Wild-Caught and Laboratory-Reared Coconut Rhinoceros Beetle, Oryctes rhinoceros (Coleoptera: Scarabaeidae), in Relation to Substrate Particle Size.

Insects, 9(4): pii:insects9040141.

The coconut rhinoceros beetle (CRB), Oryctes rhinoceros (L.) (Coleoptera: Scarabaeidae), has become one of the most important coconut and oil palm pests. This species was detected attacking coconut palms on O'ahu, Hawai'i in December 2013, and an eradication program was initiated. One of the major challenges for eradication has been the identification of new breeding sites. Information on the factors influencing oviposition is needed to aid in finding sites likely to host the immature stages of this insect. In this study, a series of choice tests were conducted to assess the oviposition preferences of both laboratory-reared and wild-caught CRB. Mated females, of both lab-reared and wild-caught beetles, were offered for oviposition a choice between sand and two mulch substrates, one with small and one with large particle sizes. Both types of CRB laid eggs preferentially in substrate of small particle size rather than large and none laid eggs in sand. Lab-reared and wild-caught CRB differed in their oviposition behavior and size. These results can be used to aid in the identification of breeding sites for management programs and eradication efforts.

RevDate: 2018-10-26

Dommanget F, Evette A, Breton V, et al (2018)

Fast-growing willows significantly reduce invasive knotweed spread.

Journal of environmental management, 231:1-9 pii:S0301-4797(18)31122-8 [Epub ahead of print].

Competitive interactions seem to play a major role in invasive plant success. However, they have mostly been addressed through the invader impacts on other species of the plant community and rarely through the way plant communities can contain alien species. Understanding such mechanisms would help in designing restoration projects using plant community competitive properties to control invasive populations. In this study, we looked at the role of competitive interactions in the success of Fallopia japonica (Houtt.) Ronse Decraene using a native willow frequently used in bioengineering techniques: Salix viminalis L. S. viminalis has a high growth rate and is, as such, a potential candidate to compete with F. japonica in restoration projects of invaded areas. Both species were grown in semi-controlled conditions in mesocosms (truck dumpsters), alone or in competition. Morphological traits (plant height, specific leaf area) as well as biomass (aboveground and underground) were measured on each species during two growing seasons. We also quantified spatial expansion of F. japonica. Even under a dense canopy of S. viminalis, F. japonica was able to survive and grow. However, its performance was significantly reduced compared to monocultures and its spatial colonization was less extended. Although S. viminalis biomass was affected by F. japonica, F. japonica expressed competitive stress through a modification of ramet density and height. There was no significant effect of F. japonica on S. viminalis height, enabling this species to dominate. Synthesis and applications: We conclude that S. viminalis succeeded in reducing F. japonica growth by developing a competitive canopy. Bioengineering techniques aiming at restoring a competitive neighborhood can control F. japonica. However, F. japonica's broad underground extension should be taken into account in any management strategy in order to successfully limit its development and spatial spread.

RevDate: 2018-10-16

Luíza Silva-Luz C, Rubens Pirani J, Daniel Mitchell J, et al (2018)

Phylogeny of Schinus L. (Anacardiaceae) with a new infrageneric classification and insights into evolution of spinescence and floral traits.

Molecular phylogenetics and evolution pii:S1055-7903(18)30329-4 [Epub ahead of print].

Schinus, best known by its few cultivated and invasive species, is the largest genus of Anacardiaceae in southern South America. It is remarkably diverse compared to closely related genera, with approximately 42 species, most of which occur in several arid vegetation types and extend into Andean and Atlantic moist forests. The most comprehensive taxonomic revision of the genus dates to 1957, recognizing S. subg. Schinus and S. subg. Duvaua, the latter of which were further divided into two sections. Subsequent studies have highlighted morphological inconsistencies in this infrageneric classification, and species delimitation remains a challenge. Schinus has been poorly sampled in previous phylogenetic studies of Anacardiaceae, and thus any assumptions about its monophyly and relationships remain untested. We investigated the phylogenetic relationships of 44 Schinus taxa and sampled 122 specimens, including the outgroup, using nine nuclear and two plastid DNA sequence regions, most of them developed recently for Commiphora (Burseraceae, sister to Anacardiaceae). We used maximum parsimony, maximum likelihood, and Bayesian inference to infer relationships among species. We also constructed a morphological dataset, including vegetative anatomical features, and compared these characters to hypotheses based on molecular evidence in order to achieve a better understanding of the relationships among the species of Schinus and to related genera, aiming also to identify morphological characters and putative synapomorphies for major clades, and to discuss hypotheses regarding the evolution of structural traits in the genus. Our analyses strongly support the monophyly of Schinus, but also indicate that S. subg. Schinus and the sections of S. subg. Duvaua are polyphyletic. The phylogenetic relationships that emerged from our analyses include eight relatively well-supported lineages, but relationships among closely related species remain unclear in some clades. Ancestral state reconstructions demonstrate that several morphological and leaf-anatomical characters are valuable in characterizing some lineages. By contrast, most of the traits that have traditionally been used to circumscribe groups in Schinus show high levels of homoplasy. In light of these results, we present a novel sectional classification of Schinus based on a combination of character states associated with geographic distribution, corresponding to lineages that are mostly allopatric or at least ecologically distinct.

RevDate: 2018-10-16

Helliwell EE, Faber-Hammond J, Lopez ZC, et al (2018)

Rapid establishment of a flowering cline in Medicago polymorpha after invasion of North America.

Molecular ecology [Epub ahead of print].

To establish and spread in a new location, an invasive species must be able to carry out its life cycle in novel environmental conditions. A key trait underlying fitness is the shift from vegetative to reproductive growth through floral development. In this study, we used a common garden experiment and genotyping-by-sequencing to test whether the latitudinal flowering cline of the North American invasive plant Medicago polymorpha was translocated from its European native range through multiple introductions, or whether the cline rapidly established due to evolution following a genetic bottleneck. Analysis of flowering time in 736 common garden plants showed a latitudinal flowering time cline in both the native and invaded ranges where genotypes from lower latitudes flowered earlier. Genotyping-by-sequencing of 9,658 SNPs in 446 individuals revealed two major subpopulations of M. polymorpha in the native range, only one of which is present in the invaded range. Additionally, native range populations have higher genetic diversity than invaded range populations, suggesting that a genetic bottleneck occurred during invasion. All invaded range individuals are closely related to plants collected from native range populations in Portugal and southern Spain, and population assignment tests assigned invaded range individuals to this same narrow source region. Taken together, our results suggest that latitudinal clinal variation in flowering time has rapidly evolved across the invaded range despite a genetic bottleneck following introduction. This article is protected by copyright. All rights reserved.

RevDate: 2018-10-16

Giakoumi S, Pey A, Di Franco A, et al (2018)

Exploring the relationships between marine protected areas and invasive fish in the world's most invaded sea.

Ecological applications : a publication of the Ecological Society of America [Epub ahead of print].

Marine Protected Areas (MPAs) are an essential tool for marine biodiversity conservation. Yet, their effectiveness in protecting marine ecosystems from global stressors is debated. Biological invasions are a major driver of global change, causing biodiversity loss and altering ecosystem functioning. Here, we explored the relationships between MPAs and alien/ native range expanding fishes in the Mediterranean Sea, the world's most invaded sea. We surveyed fish and benthic communities in nine MPAs and adjacent unprotected areas across six countries. In the South and Eastern Mediterranean MPAs, the biomass of alien and native range expanding fishes often exceeded 50% of the total fish biomass. Conversely, in the North and Western Mediterranean, alien fishes were absent. A negative relationship was found between native and alien species richness. Average and minimum sea surface temperature (SST) over six consecutive years were positively correlated with the total biomass of alien species; no alien fishes were recorded below 20.5 °C average SST and 13.8° C minimum SST. We also found a negative relationship between alien fishes' biomass and the distance from the Suez Canal which is the main pathway for the introduction of alien fish in the Mediterranean Sea. The biomass of alien and native range expanding fishes was found to be higher in the South and Eastern Mediterranean MPAs than in adjacent unprotected areas. The association of barrens (rocky reefs deprived of vegetation) and invasive herbivores was observed at all eastern sites, regardless of protection status. Currently, the level of fishing pressure exerted on alien and native range expanding fishes seems to be the most influential factor determining the lower biomass of invasive fishes at unprotected sites compared to MPAs. Our findings suggest that complementary management actions, such as species-targeted removals, should be taken in MPAs in order to control invasive fish populations. This article is protected by copyright. All rights reserved.

RevDate: 2018-10-16

Yang Q, Liu S, He C, et al (2018)

Invisible apple snail invasions: importance of continued vigilance and rigorous taxonomic assessments.

Pest management science [Epub ahead of print].

BACKGROUND: Due to the similarities of overall shell morphology among apple snail species and considerable variability within species, substantial taxonomic confusion has plagued the accurate identification of Pomacea species. Many invasive apple snails have been mistakenly identified as P. canaliculata since their introduction to Asia around 1980. In 2008, three other introduced species in addition to P. canaliculata were recognized. In 2013, a fifth, previously unrecognized lineage was reported from China, indicating that despite the taxonomic clarity brought by previous work, continued surveys and taxonomic research are necessary to prevent additional introductions and continued spread, as well as to develop effective management strategies.

RESULTS: Phylogenetic analysis of mitochondrial COI sequences confirmed the presence of a widespread unidentified Pomacea lineage in China. All sequences from samples of this newly documented lineage were recovered in a monophyletic clade delineated from closely related species; however, different DNA barcoding methods yielded inconsistent species boundaries. Additionally, nuclear EF1α sequences indicated incomplete lineage sorting or recent hybridization of the unidentified lineage with the other two established species.

CONCLUSION: Barcoding is a valuable tool for species discovery, and a powerful approach for delineating introduced species. However, determining the identity of the newly discovered invasive lineage in China will require an integrated taxonomic approach incorporating individuals from the native range, and examination of natural history collections at museums around the world. To manage and prevent additional spread of already established species, and to stop the introduction of new taxa, continued monitoring and rigorous taxonomic assessments must be undertaken. This article is protected by copyright. All rights reserved.

RevDate: 2018-10-18

Weterings R, KC Vetter (2018)

Invasive house geckos (hemidactylus spp.): their current, potential and future distribution.

Current zoology, 64(5):559-573.

In this study, we identified the current distribution of five globally distributed invasive Hemidactylus species and predicted their potential and future distribution using species distribution models based on climate and elevation data. These species included H. brookii, H. frenatus, H. garnotii, H. mabouia, and H. turcicus. We show that many regions with tropical and Mediterranean climates are suitable for most of these species. However, their current and potential distributions suggest that climate is not the only limiting factor. We hypothesize that climatic conditions may affect competition and other interactions resulting in a segregated distribution of the studied Hemidactylus species. As an effect of global climate change it is likely that H. brookii will expand its range to areas that are currently colonized by H. mabouia and/or H. frenatus, while H. turcicus is likely to expand its range to areas that are not yet invaded by any Hemidactylus species. The role of species interactions in the range expansion of these five Hemidactylus species still remains poorly understood, but could be of major importance in understanding and managing these invasive species.

RevDate: 2018-10-23

Robinson LA, Blincow HL, Culhane FE, et al (2018)

Identifying barriers, conflict and opportunity in managing aquatic ecosystems.

The Science of the total environment, 651(Pt 2):1992-2002 pii:S0048-9697(18)33893-2 [Epub ahead of print].

Inland aquatic ecosystems play an important part in the delivery and support of ecosystem services. However, these ecosystems are subject to stressors associated with human activities such as invasive species introduction and landscape alteration. There is a delicate balance between maintaining good status of the ecosystem whilst meeting the needs of those stakeholders dependent on the ecosystem services it supplies, and where there are many different stakeholders, each with different aspirations and dependencies on the ecosystem, it can be difficult to strike a balance on suitable management measures to put in place. A better understanding of the interactions between the human and ecological functions of the ecosystem (a socio-ecological systems (SES) approach) can enable an effective dialogue to be opened to secure management solutions of best fit. In this study we took a SES approach to explore the dependencies and interactions in the Lough Erne catchment with a range of stakeholders representing the use of the Lough. In particular, we explored how individual stakeholder goals were perceived to be affected by both the biodiversity and activities found in the catchment. Results suggest there are distinct components deemed integral to the success of stakeholder goals in this system, including 'key habitat components' and 'policy relevant species', as well as activities associated with 'conservation and recreation' and 'scientific research'. Those components which were seen to limit the potential achievement of most goals included invasive species, and in particular, more recently introduced invasives, as well as extractive industries. Consideration of the similarity in goals based on their perceived interactions with the activities and biodiversity of the system indicated that there were shared dependencies between some stakeholders, but also differences that highlight the potential for conflict. Future management scenarios should take consideration of the key limiting and enabling factors identified here.

RevDate: 2018-10-14

Brzeziński M, Chibowski P, Gornia J, et al (2018)

Spatio-temporal variation in nesting success of colonial waterbirds under the impact of a non-native invasive predator.

Oecologia pii:10.1007/s00442-018-4270-8 [Epub ahead of print].

Colonial breeding in birds provides protection from predators and may be particularly important when birds have to cope with an invasive predator. The probability of nest predation in a colony can vary depending on several factors, such as the nest's location in the colony and the level of aggregation of nests. We studied the nesting success of colonial great crested grebes and monitored the occurrence of the non-native invasive American mink in the colony. From among 92 grebe nests, 54.3% were successful. The daily survival rate (DSR) of grebe nests was positively affected by the increasing distance between the nest and lake shoreline, and negatively affected by the increasing distance between the nest and the five nearest grebe nests. The probability of mink occurrence in the colony increased with consecutive days of the breeding season and decreased with increasing distance from the lake shoreline. The DSR of grebe nests decreased with the increasing probability of mink occurrence along the shoreline distance gradient and the day of the breeding season. The results of the study confirm the impact of the American mink on waterbirds during the breeding season but also indicate that large breeding colonies are partially safe from mink predation, and that nest accessibility and the dilution effect influence the probability of nest survival. Our data suggest that the limited access to safe breeding sites on large lakes that can supply adult grebes and their chicks with food may affect bird productivity and population numbers at the landscape level.

RevDate: 2018-10-16

Zhong L, Wang M, Li D, et al (2018)

Complete mitochondrial genome of freshwater goby Rhinogobius cliffordpopei (Perciformes, Gobiidae): genome characterization and phylogenetic analysis.

Genes & genomics, 40(11):1137-1148.

Freshwater gobies Rhinogobius cliffordpopei and R. giurinus are invasive species with particular concern because they have become dominant and were fierce competitors in the invaded areas in Yunnan-Guizhou Plateau (southwest of China). Information about genetic characteristics of R. giurinus have been published, but there were still no relevant reports about R. cliffordpopei. In present study, the complete mitochondrial genome of R. cliffordpopei was determined, which was 16,511 bp in length with A + T content of 51.1%, consisting of 13 protein-coding genes, 22 tRNAs, 2 ribosomal RNAs, and a control region. The gene composition and the structural arrangement of the R. cliffordpopei complete mtDNA were identical to most of other teleosts. Phylogenetic analyses placed R. cliffordpopei in a well-supported monophyletic cluster with other Rhinogobius fish. But the phylogenetic relationship between genus Rhinogobius and Tridentiger remained to be resolved.

RevDate: 2018-10-13

d'Ovidio D, F Pirrone (2018)

A cross-sectional survey to evaluate the pet squirrel population and ownership profiles.

Preventive veterinary medicine, 159:65-71.

While the presence of squirrels in households is growing, little data is published on their status in captivity. A web-based questionnaire for owners was devised eliciting information about them, their squirrels and their squirrels' husbandry and health. One hundred owners answered the survey, with most respondents being located in Europe (n = 81). Only data from these respondents were analysed. Twenty-five percents of the owners housed an invasive non-native species of European Union concern (S. carolinensis and T. sibiricus), some of which were younger than three years of age and all but one were sexually intact. This is of particular concern, as the acquisition of these invasive species is illegal since 2015 (European Union Regulation 1143/2014), due to the severe threats they pose to biodiversity. Moreover, escapes derived from improper keeping of intact specimens may augment feral populations or establish new colonies. Among 81 cases, only 5% were neutered, mostly for health reasons. Sixty-three percents of the squirrels had health problems, particularly dermatologic (52%) and intestinal disorders (34%). Most owners reported to visit the veterinarian only if their pet was ill rather than for preventive care. This is the first survey on pet squirrel ownership reported to date. Information that emerges from this study will be useful in implementing rational veterinary strategies for managing pet squirrels properly and, in parallel, meeting the challenges arising from private keeping of alien species.

RevDate: 2018-10-13

Wright JT, Holmes ZC, JE Byers (2018)

Stronger positive association between an invasive crab and a native intertidal ecosystem engineer with increasing wave exposure.

Marine environmental research pii:S0141-1136(18)30481-1 [Epub ahead of print].

Ecosystem engineers are predicted to have stronger facilitative effects when environmental stress is higher. Here we examined whether facilitation of the invasive porcelain crab Petrolisthes elongatus by the ecosystem engineering serpulid tube worm Galeolaria caespitosa increased with wave exposure. Petrolisthes occurs beneath intertidal boulders which often have a high cover of Galeolaria on their underside. Surveys across nine sites demonstrated Petrolisthes abundance beneath boulders increased with wave exposure and Galeolaria cover, although only when the habitat matrix beneath boulders was rock or mixed rock and sand. Moreover, as wave exposure increased, the strength of relationship between Petrolisthes abundance and the surface area of Galeolaria also increased. Experimentally, the presence of Galeolaria on the underside of boulders increased Petrolisthes abundance by 50% compared to boulders lacking Galeolaria. Our findings suggest the facilitative role of Galeolaria is stronger at more wave-exposed sites, which appears to contribute to a higher abundance of invasive Petrolisthes.

RevDate: 2018-10-13

Powell JR (2018)

Genetic Variation in Insect Vectors: Death of Typology?.

Insects, 9(4): pii:insects9040139.

The issue of typological versus population thinking in biology is briefly introduced and defined. It is then emphasized how population thinking is most relevant and useful in vector biology. Three points are made: (1) Vectors, as they exist in nature, are genetically very heterogeneous. (2) Four examples of how this is relevant in vector biology research are presented: Understanding variation in vector competence, GWAS, identifying the origin of new introductions of invasive species, and resistance to inbreeding. (3) The existence of high levels of vector genetic heterogeneity can lead to failure of some approaches to vector control, e.g., use of insecticides and release of sterile males (SIT). On the other hand, vector genetic heterogeneity can be harnessed in a vector control program based on selection for refractoriness.

RevDate: 2018-10-23

Bick A, Bastrop R, Kotta J, et al (2018)

Description of a new species of Sabellidae (Polychaeta, Annelida) from fresh and brackish waters in Europe, with some remarks on the branchial crown of Laonome.

Zootaxa, 4483(2):349-364 pii:zootaxa.4483.2.7.

In 2009, a hitherto unknown Laonome species was found in the Canal Ghent-Terneuzen in the Netherlands and subsequently in other Dutch rivers, canals and estuaries. A few years later, more unknown Laonome specimens were found in the eastern part of the Baltic Sea and in the Don River estuary, Sea of Azov. Initially, it was assumed that these specimens could represent Laonome calida Capa, 2007, originally described from Australia. In the present study we examine all these unknown European Laonome specimens and compare these specimens with the type material of L. calida from Australia. This lead to two main results: First, all specimens from Europe have the same diagnostic characters and therefore belong to one species. This finding was also supported by the results of a correspondence analysis, and genetic analyses using four different DNA sequences (COI, 16S, 28S). Second, it turned out that the type material of L. calida contains two morphologically distinct groups of specimens. The holotype and 7 paratypes are similar to each other but differ significantly from the other also similar 16 paratypes, and from all European specimens. On the basis of these observations, the Laonome specimens from European waters are described here as L. xeprovala sp. nov. We also provide the characters of the branchial crown of three Laonome species for a prospective revision of this genus.

RevDate: 2018-10-23

Bronstein O, A Kroh (2018)

Needle in a haystack-genetic evidence confirms the expansion of the alien echinoid Diadema setosum (Echinoidea: Diadematidae) to the Mediterranean coast of Israel.

Zootaxa, 4497(4):593-599 pii:zootaxa.4497.4.9.

Diadema setosum (Leske, 1778), a widespread tropical echinoid and key herbivore in shallow water environments is currently expanding in the Mediterranean Sea. It was introduced by unknown means and first observed in southern Turkey in 2006. From there it spread eastwards to Lebanon (2009) and westwards to the Aegean Sea (2014). Since late 2016 sporadic sightings of black, long-spined sea urchins were reported by recreational divers from rock reefs off the Israeli coast. Numerous attempts to verify these records failed; neither did the BioBlitz Israel task force encounter any D. setosum in their campaigns. Finally, a single adult specimen was observed on June 17, 2017 in a deep rock crevice at 3.5 m depth at Gordon Beach, Tel Aviv. Although the specimen could not be recovered, spine fragments sampled were enough to genetically verify the visual underwater identification based on morphology. Sequences of COI, ATP8-Lysine, and the mitochondrial Control Region of the Israel specimen are identical to those of the specimen collected in 2006 in Turkey, unambiguously assigning the specimen to D. setosum clade b. This lends support to the hypothesis of a single introduction event and fits well with the habitat suitability and distribution model for D. setosum published recently. The more rapid and larger range extension along a south-eastern, counter-current trajectory may reflect a strong habitat preference for D. setosum in this area of the Levantine Basin as predicted by the model.

RevDate: 2018-10-23

BieŃkowski AO (2018)

Key for identification of the ladybirds (Coleoptera: Coccinellidae) of European Russia and the Russian Caucasus (native and alien species).

Zootaxa, 4472(2):233-260 pii:zootaxa.4472.2.2.

Although ladybirds of European Russia and the Caucasus have been the subject of numerous ecological and faunistic investigations, there is an evident lack of appropriate identification keys. New, original keys to subfamilies, tribes, genera, and species of ladybirds (Coccinellidae) of European Russia and the Russian Caucasus are presented here. The keys include all native species recorded in the region and all introduced alien species. Some species from adjacent regions are added. In total, 113 species are treated and illustrated with line drawings. Photographs of rare and endemic species are provided. Information on the distribution of species within the region under consideration is provided. Chilocorus kuwanae Silvestri, 1909 is recognized as a subjective junior synonym (syn. nov.) of Ch. renipustulatus (Scriba, 1791).

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In the early 1990's, Robert Robbins was a faculty member at Johns Hopkins, where he directed the informatics core of GDB — the human gene-mapping database of the international human genome project. To share papers with colleagues around the world, he set up a small paper-sharing section on his personal web page. This small project evolved into The Electronic Scholarly Publishing Project.

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In 1995, Robbins became the VP/IT of the Fred Hutchinson Cancer Research Center in Seattle, WA. Soon after arriving in Seattle, Robbins secured funding, through the ELSI component of the US Human Genome Project, to create the original ESP.ORG web site, with the formal goal of providing free, world-wide access to the literature of classical genetics.

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Although the methods of molecular biology can seem almost magical to the uninitiated, the original techniques of classical genetics are readily appreciated by one and all: cross individuals that differ in some inherited trait, collect all of the progeny, score their attributes, and propose mechanisms to explain the patterns of inheritance observed.

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In reading the early works of classical genetics, one is drawn, almost inexorably, into ever more complex models, until molecular explanations begin to seem both necessary and natural. At that point, the tools for understanding genome research are at hand. Assisting readers reach this point was the original goal of The Electronic Scholarly Publishing Project.

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Usage of the site grew rapidly and has remained high. Faculty began to use the site for their assigned readings. Other on-line publishers, ranging from The New York Times to Nature referenced ESP materials in their own publications. Nobel laureates (e.g., Joshua Lederberg) regularly used the site and even wrote to suggest changes and improvements.

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When the site began, no journals were making their early content available in digital format. As a result, ESP was obliged to digitize classic literature before it could be made available. For many important papers — such as Mendel's original paper or the first genetic map — ESP had to produce entirely new typeset versions of the works, if they were to be available in a high-quality format.

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With the development of methods for adding typeset side notes to PDF files, the ESP project now plans to add annotated versions of some classical papers to its holdings. We also plan to add new reference and pedagogical material. We have already started providing regularly updated, comprehensive bibliographies to the ESP.ORG site.

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This is a must read book for anyone with an interest in invasion biology. The full title of the book lays out the author's premise — The New Wild: Why Invasive Species Will Be Nature's Salvation. Not only is species movement not bad for ecosystems, it is the way that ecosystems respond to perturbation — it is the way ecosystems heal. Even if you are one of those who is absolutely convinced that invasive species are actually "a blight, pollution, an epidemic, or a cancer on nature", you should read this book to clarify your own thinking. True scientific understanding never comes from just interacting with those with whom you already agree. R. Robbins

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Papers in Classical Genetics

The ESP began as an effort to share a handful of key papers from the early days of classical genetics. Now the collection has grown to include hundreds of papers, in full-text format.

Digital Books

Along with papers on classical genetics, ESP offers a collection of full-text digital books, including many works by Darwin (and even a collection of poetry — Chicago Poems by Carl Sandburg).

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Biographical information about many key scientists.

Selected Bibliographies

Bibliographies on several topics of potential interest to the ESP community are now being automatically maintained and generated on the ESP site.

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