An Exotic Species Is the Favorite Prey of a Native Enemy

Although native enemies in an exotic species' new range are considered to affect its ability to invade, few studies have evaluated predation pressures from native enemies on exotic species in their new range. The exotic prey naiveté hypothesis (EPNH) states that exotic species may be at a disadvantage because of its naïveté towards native enemies and, therefore, may suffer higher predation pressures from the enemy than native prey species. Corollaries of this hypothesis include the native enemy preferring exotic species over native species and the diet of the enemy being influenced by the abundance of the exotic species. We comprehensively tested this hypothesis using introduced North American bullfrogs (Lithobates catesbeianus, referred to as bullfrog), a native red-banded snake (Dinodon rufozonatum, the enemy) and four native anuran species in permanent still water bodies as a model system in Daishan, China. We investigated reciprocal recognition between snakes and anuran species (bullfrogs and three common native species) and the diet preference of the snakes for bullfrogs and the three species in laboratory experiments, and the diet preference and bullfrog density in the wild. Bullfrogs are naive to the snakes, but the native anurans are not. However, the snakes can identify bullfrogs as prey, and in fact, prefer bullfrogs over the native anurans in manipulative experiments with and without a control for body size and in the wild, indicating that bullfrogs are subjected to higher predation pressures from the snakes than the native species. The proportion of bullfrogs in the snakes' diet is positively correlated with the abundance of bullfrogs in the wild. Our results provide strong evidence for the EPNH. The results highlight the biological resistance of native enemies to naïve exotic species

Increasing Potential Risk of a Global Aquatic Invader in Europe in Contrast to Other Continents under Future Climate Change

BACKGROUND: Anthropogenically-induced climate change can alter the current climatic habitat of non-native species and can have complex effects on potentially invasive species. Predictions of the potential distributions of invasive species under climate change will provide critical information for future conservation and management strategies. Aquatic ecosystems are particularly vulnerable to invasive species and climate change, but the effect of climate change on invasive species distributions has been rather neglected, especially for notorious global invaders. METHODOLOGY/PRINCIPAL FINDINGS: We used ecological niche models (ENMs) to assess the risks and opportunities that climate change presents for the red swamp crayfish (Procambarus clarkii), which is a worldwide aquatic invasive species. Linking the factors of climate, topography, habitat and human influence, we developed predictive models incorporating both native and non-native distribution data of the crayfish to identify present areas of potential distribution and project the effects of future climate change based on a consensus-forecast approach combining the CCCMA and HADCM3 climate models under two emission scenarios (A2a and B2a) by 2050. The minimum temperature from the coldest month, the human footprint and precipitation of the driest quarter contributed most to the species distribution models. Under both the A2a and B2a scenarios, P. clarkii shifted to higher latitudes in continents of both the northern and southern hemispheres. However, the effect of climate change varied considerately among continents with an expanding potential in Europe and contracting changes in others. CONCLUSIONS/SIGNIFICANCE: Our findings are the first to predict the impact of climate change on the future distribution of a globally invasive aquatic species. We confirmed the complexities of the likely effects of climate change on the potential distribution of globally invasive species, and it is extremely important to develop wide-ranging and effective control measures according to predicted geographical shifts and changes

An established population of African clawed frogs, Xenopus laevis (Daudin, 1802), in mainland China

CITATION: Wang, S., Hong, Y. & Measey, J. 2019. An established population of African clawed frogs, Xenopus laevis (Daudin, 1802), in mainland China. BioInvasions Records, 8(2):457-464, doi:10.3391/bir.2019.8.2.29.The original publication is available at https://www.reabic.netENGLISH ABSTRACT: Reports of amphibian invasions are increasing, although it seems likely that there are more extant populations of alien species than we are currently aware of, and we are far from understanding their full environmental and economic impact. Here we provide data on another established population of African clawed frogs, Xenopus laevis (Daudin, 1802); from Yunnan Province in mainland China. The site is an aquaculture area immediately adjacent to the northern shores of Lake Kunming. This report is significant as it is the first known alien population of an albino form of this species, the form that is most prevalent in the pet trade. We call for urgent surveys using eDNA to determine the extent of the invasion of this cryptic amphibian invader around Lake Kunming, as well as studies to determine the environmental and economic impacts at this site, which is already known for an invasion of American bullfrogs, Lithobates catesbeianus (Shaw, 1802).https://www.reabic.net/journals/bir/2019/2/BIR_2019_Wang_etal.pdfPublisher's versio

Projected impacts of climate change on future invasive potential of <i>P. clarkii.</i>

<p>Models were developed with a consensus-forecast approach using the CCCMA and HADCM3 climate models under two scenarios (A2a and B2a) by 2050: blue  =  current suitable areas projected to be lost with global climate change; black  =  current suitable areas projected to be retained; and red  =  areas projected to become suitable. The predicted suitability is based on the 10th percentile training presence threshold.</p

Influence of Novel Highly Pathogenic Avian Influenza A (H5N1) Virus Infection on Migrating Whooper Swans Fecal Microbiota

The migration of wild birds plays an important role in the transmission and spread of H5 highly pathogenic avian influenza (HPAI) virus, posing a severe risk to animal and human health. Substantial evidence suggests that altered gut microbial community is implicated in the infection of respiratory influenza virus. However, the influence of H5N1 infection in gut microbiota of migratory birds remains unknown. In January 2015, a novel recombinant H5N1 virus emerged and killed about 100 migratory birds, mainly including whooper swans in Sanmenxia Reservoir Area of China. Here, we describe the first fecal microbiome diversity study of H5N1-infected migratory birds. By investigating the influence of H5N1 infection on fecal bacterial communities in infected and uninfected individuals, we found that H5N1 infection shaped the gut microbiota composition by a difference in the dominance of some genera, such as Aeromonas and Lactobacillus. We also found a decreased α diversity and increased β diversity in infectious individuals. Our results highlight that increases in changes in pathogen-containing gut communities occur when individuals become infected with H5N1. Our study may provide the first evidence that there are statistical association among H5N1 presence and fecal microbiota compositional shifts, and properties of the fecal microbiota may serve as the risk of gut-linked disease in migrates with H5N1 and further aggravate the disease transmission

Climate change, biogeography and shift in range size of future invasive potential of <i>P. clarkii</i>.

<p>Projected latitudinal pattern of suitability changes between the present year and 2050 for two scenarios (A2a and B2a) with global climate change (blue, current suitable areas projected to be lost; and red, the proportion of areas projected to become suitable). The predicted suitability is based on the 10th percentile training presence threshold.</p

Data from: Pathogen richness and abundance predict patterns of adaptive MHC variation in insular amphibians

The identification of the factors responsible for genetic variation and differentiation at adaptive loci can provide important insights into the evolutionary process, and is crucial for the effective management of threatened species. We studied the impact of environmental viral richness and abundance on functional diversity and differentiation of the MHC class Ia locus in populations of the black-spotted pond frog (Pelophylax nigromaculatus), an IUCN-listed species, on 24 land-bridge islands of the Zhoushan Archipelago and 3 nearby mainland sites. We found a high proportion of private MHC alleles in mainland and insular populations, corresponding to 32 distinct functional supertypes, and strong positive selection on MHC antigen-binding sites in all populations. Viral pathogen diversity and abundance was reduced at island sites relative to the mainland, and islands housed distinctive viral communities. Standardized MHC diversity at island sites exceeded that found at neutral microsatellites, and the representation of key functional supertypes was positively correlated with the abundance of specific viruses in the environment (Frog virus 3 and Ambystoma tigrinum virus). These results indicate that pathogen-driven diversifying selection can play an important role in maintaining functionally-important MHC variation following island isolation, highlighting the importance of considering functionally important genetic variation and host-pathogen associations in conservation planning and management