Estimativas populacionais de Dendrobates tinctorius (Anura: Dendrobatidae) em três áreas da Guiana Francesa e primeiro relato de quitridiomicose.

A região Neotropical abriga o maior número de espécies de anuros da Terra e é também uma das regiões em que os anfíbios estão mais ameaçados. No entanto, poucos dados estão atualmente disponíveis para avaliar a situação daspopulações de anfíbios neotropicais. Estudamos três populações de Dendrobates tinctorius na Guiana Francesa (Tresor, Favard e Nouragues) usando o modelo de Captura-Marcação-Recaptura (CMR) para a realização de estimativas robustas da densidade da espécie nesses três locais. Além disso, avaliamos a prevalência do fungo patogênico Batrachochytrium dendrobatidis (Bd) em duaspopulações (Favard and Nouragues). O uso do modelo CMR revelou uma densidade de 4,67 indivíduos/100 m² para Tresor, 8,43 indivíduos/100 m² para Favard e 4,28 indivíduos/100 m² para Nouragues, fornecendo estimativas das densidades populacionais de D. tinctorius na Guiana Francesa com as quais estimativas populacionais futuras poderão ser comparadas. Constatamos que 25 ocasiões de encontro podem ser suficientes para estimativas de uma população estável se as capturas forem concentradas no tempo. Bd foi detectado em ambas as áreas (Favard 7/152, Nouragues 3/18). Propomos, portanto, o início de um acompanhamento de longa-duração dessa espécie em vários locais (dentro e fora de áreas protegidas) da Guiana Francesa, combinando estudos de CMR com ocasiões de encontros concentrados em um curto período de tempo e o monitoramento de Bd.The Neotropics shelter the highest number of frog species on Earth and is also one of the regions where anurans aremost threatened. Nonetheless, few data are available to assess the population status of Neotropical anurans. We studied three populations (Tresor, Favard, and Nouragues) of the poison frog, Dendrobates tinctorius, in French Guiana and used Capture-Mark-Recapture (CMR) to make robust estimations of the species’ density at these three sites. In addition, we assessed the prevalence of the pathogen fungal Batrachochytrium dendrobatidis (Bd) in two populations (Favard and Nouragues). Based on the CMR protocol, the densities of frogs was 8.43 individuals/100 m² at Favard, 4.28 individuals/100 m² at Nouragues and from 2.30 to 4.67 individuals/100 m² at Tresor (depending on the CMR model used); these data provide a baseline for population densities of D. tinctorius in French Guiana, against which future population estimates can be compared. We found that 25 encounter events may be sufficient for stable population estimates, if the captures are concentrated in time. Bd was detected at both sites (Favard 7/152; Nouragues 3/18)

Introducing water frogs – Is there a risk for indigenous species in France?

The ecological success of introduced species in their new environments is difficult to predict. Recently, the water frog species Rana ridibunda has raised interest, as different genetic lineages were introduced to various European countries. The aim of the present study was to analyze the potential invasiveness of R. ridibunda and assess the risk of replacement for indigenous water frog species. The investigation of over 700 water frogs from 22 locations in southern France and four locations in Spain shows that the competition with indigenous species is mainly limited to a particular habitat type, characterized by high-oxygen and low-salinity freshwater. The competitive strength of R. ridibunda may be related to a higher growth rate and longevity as compared to the indigenous species R. grafi and R. perezi. Our data suggest that R. ridibunda is a risk to the diversity of indigenous water frog assemblages in France. Future monitoring needs to clarify the distribution of R. ridibunda, its ecological niche, and the risk status for indigenous water frog species

Setting temporal baselines for biodiversity : the limits of available monitoring data for capturing the full impact of anthropogenic pressures

Temporal baselines are needed for biodiversity, in order for the change in biodiversity to be measured over time, the targets for biodiversity conservation to be defined and conservation progress to be evaluated. Limited biodiversity information is widely recognized as a major barrier for identifying temporal baselines, although a comprehensive quantitative assessment of this is lacking. Here, we report on the temporal baselines that could be drawn from biodiversity monitoring schemes in Europe and compare those with the rise of important anthropogenic pressures. Most biodiversity monitoring schemes were initiated late in the 20th century, well after anthropogenic pressures had already reached half of their current magnitude. Setting temporal baselines from biodiversity monitoring data would therefore underestimate the full range of impacts of major anthropogenic pressures. In addition, biases among taxa and organization levels provide a truncated picture of biodiversity over time. These limitations need to be explicitly acknowledged when designing management strategies and policies as they seriously constrain our ability to identify relevant conservation targets aimed at restoring or reversing biodiversity losses. We discuss the need for additional research efforts beyond standard biodiversity monitoring to reconstruct the impacts of major anthropogenic pressures and to identify meaningful temporal baselines for biodiversity

Microbiome function predicts amphibian chytridiomycosis disease dynamics

[Background] The fungal pathogenBatrachochytrium dendrobatidis (Bd) threatens amphibian biodiversity and ecosystem stability worldwide. Amphibian skin microbial community structure has been linked to the clinical outcome of Bd infections, yet its overall functional importance is poorly understood. [Methods] Microbiome taxonomic and functional profiles were assessed using high-throughput bacterial 16S rRNA and fungal ITS2 gene sequencing, bacterial shotgun metagenomics and skin mucosal metabolomics. We sampled 56 wild midwife toads (Alytes obstetricans) from montane populations exhibiting Bd epizootic or enzootic disease dynamics. In addition, to assess whether disease-specific microbiome profiles were linked to microbe-mediated protection or Bd-induced perturbation, we performed a laboratory Bd challenge experiment whereby 40 young adult A. obstetricans were exposed to Bd or a control sham infection. We measured temporal changes in the microbiome as well as functional profiles of Bd-exposed and control animals at peak infection. [Results] Microbiome community structure and function differed in wild populations based on infection history and in experimental control versus Bd-exposed animals. Bd exposure in the laboratory resulted in dynamic changes in microbiome community structure and functional differences, with infection clearance in all but one infected animal. Sphingobacterium, Stenotrophomonas and an unclassified Commamonadaceae were associated with wild epizootic dynamics and also had reduced abundance in laboratory Bd-exposed animals that cleared infection, indicating a negative association with Bd resistance. This was further supported by microbe-metabolite integration which identified functionally relevant taxa driving disease outcome, of which Sphingobacterium and Bd were most influential in wild epizootic dynamics. The strong correlation between microbial taxonomic community composition and skin metabolome in the laboratory and field is inconsistent with microbial functional redundancy, indicating that differences in microbial taxonomy drive functional variation. Shotgun metagenomic analyses support these findings, with similar disease-associated patterns in beta diversity. Analysis of differentially abundant bacterial genes and pathways indicated that bacterial environmental sensing and Bd resource competition are likely to be important in driving infection outcomes. [Conclusions] Bd infection drives altered microbiome taxonomic and functional profiles across laboratory and field environments. Our application of multi-omics analyses in experimental and field settings robustly predicts Bd disease dynamics and identifies novel candidate biomarkers of infection. [MediaObject not available: see fulltext.]K.A.B. was funded by a CASE studentship from NERC, NERC Biomolecular Analysis Facility grant (NBAF939) and an E.P. Abraham Junior Research Fellowship from St Hilda’s College, University of Oxford. M.C.F and T.W.J.G. were funded by NERC award NE/E006701/1 and the Biodiversa project RACE: Risk Assessment of Chytridiomycosis to European Amphibian Biodiversity. T.W.J.G was also funded by Research England and NERC NE/S000062/1. D.S.S. and A.L. received funding through the project People, Pollution, and Pathogens financed through the call “Mountains as Sentinels of Change” by the Belmont-Forum (ANR-15-MASC-0001 - P3, DFG-SCHM3059/6-1, NERC-1633948, NSFC-41661144004). D.S.S. holds the AXA Chair for Functional Mountain Ecology funded by the AXA Research Fund through the project GloMEc and M.C.F. is a fellow in the CIFAR ‘Fungal Kingdoms’ Program

The Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES): progress and next steps

Biodiversity and the services ecosystems provide have built the foundation of human civilization and provide for the welfare of people. With the increase of the human population it has become clearer than ever that the human exploitation of our natural resources leads to detrimental interactions between ecological and sociological systems. Only concerted and global actions will be able to reverse ongoing biodiversity loss. In response to these needs, the United Nations agreed the establishment of the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES) in 2010. Here, we report on the progress IPBES has made since its inception, and suggest how the scientific community can engage with this important science-policy interfac

Toward a set of essential biodiversity variables for assessing change in mountains globally

Mountain regions harbor unique and rich biodiversity, forming an important part of our global life support system. This rich biodiversity underpins the ecological intactness and functioning of mountain ecosystems, which are imperative for the provision of key ecosystem services. A considerable amount of data are required to assess ecological intactness and ecosystem functioning and, given the profound anthropogenic pressures many mountain regions are being subjected to, are urgently needed. However, data on mountain biodiversity remain lacking. The essential biodiversity variables (EBVs) framework can help focus efforts related to detecting, investigating, predicting, and managing global biodiversity change, but has not yet been considered in the context of mountains. Here, we review key biological processes and physical phenomena that strongly influence mountain biodiversity and ecosystems and elucidate their associations with potential mountain EBVs. We identify seven EBVs of highest relevance for tracking and understanding the most critical drivers and responses of mountain biodiversity change. If they are implemented, the selected EBVs will contribute useful information to inform management and policy interventions seeking to halt mountain biodiversity loss and maintain functional mountain ecosystems