David Lesbarrères

• PhD
• Conservation Scientist at Environment Canada

To the Editor: Although the relationship between the emergence of zoonotic diseases and human influenced landscapes is accepted, the relationship between human-influenced landscapes and wildlife disease is less so. Evidence does support correlations between human activities and environmental conditions affecting wildlife disease emergence. These st...

Abstract Considerable effort has been invested in studying the relationship between fitness and genetic variability. While evidence exists both for and against positive genetic variability-fitness correlations (GFC), the possible environment and population-dependency of GFCs has seldom been tested. We investigated GFCs in common frog (Rana temporar...

Emerging infectious diseases are a significant threat to global biodiversity. While historically overlooked, a group of iridoviruses in the genus Ranavirus has been responsible for die-offs in captive and wild amphibian, reptile and fish populations around the globe over the past two decades. In order to share contemporary information on ranaviruse...

Roads impede animal movement, which decreases habitat accessibility and reduces gene flow. Ecopassages have been built to mitigate this but there is little research with which to evaluate their effectiveness, owing to the difficulty in accessing results of existing research; the lack of scientific rigor in these studies; and the low priority of con...

1. Recently habitat degradation, road construction and traffic have all increased with human populations, to the detriment of aquatic habitats and species. While numerous restoration programmes have been carried out, there is an urgent need to follow their success to better understand and compensate for the decline of amphibian populations. To this...

Retaining sufficient genetic variation for both short and long-term sustainability is a chief aim of ex situ programs for threatened species. Conservation breeding and reintroduction programs exist but oftentimes little is known about the genetic variation of in situ or ex situ populations. We collected genetic samples from both wild and zoo popula...

Roadkill is widely recognized as one of the primary negative effects of roads on many wildlife species and also has socioeconomic impacts when they result in accidents. A comprehensive dataset of roadkill locations is essential to evaluate the factors contributing to roadkill risk and to enhance our comprehension of its impact on wildlife populatio...

Prey can respond to predation risk through developmental plasticity, generating anti-predator phenotypes. These inducible defenses arise from changes to the stress axis, and neuroendocrine-triggered gene regulation is a likely mechanism influencing such phenotypes. As tadpoles, amphibians improve their escape performance by modifying tail shape in...

Roads are pervasive and ubiquitous landscape features that have substantial and predominantly negative effects on wildlife. Conducting road surveys to count animals that have been struck and killed by vehicles is a common method for estimating the impact of roads on wildlife, especially for species at risk and animals with low road avoidance (i.e.,...

Context Linear Transportation Infrastructures (LTIs) are among the largest factors responsible for landscape fragmentation, in turn increasing population isolation. In this context, studies have mainly focused on a single species’ response to barrier elements and mitigation thereof. Yet, the implementation of conservation strategies to restore land...

Given widespread biodiversity declines, there is an urgent need to ensure that conservation interventions are working. Yet, evidence regarding the effectiveness of conservation actions is often lacking. Using a case study of 209 terrestrial species listed as Endangered in Canada, we conducted a literature review to collate the evidence base on cons...

The One Health High-Level Expert Panel’s definition of One Health includes optimizing the health of people, animals (wild and domestic) and ecosystems. For many One Health practitioners, wildlife that can spread zoonoses are the focus, particularly if they can come in contact with people. However, ecosystem health is often best-indicated by less-en...

Members of the Iridoviridae family, genus Ranavirus, represent a group of globally emerging pathogens of ecological and economic importance. In 2017, an amphibian die-off of wood frogs (Rana sylvatica) and boreal chorus frogs (Pseudacris maculata) was reported in Wood Buffalo National Park, Canada. Isolation and complete genomic sequencing of the t...

The northern leopard frog (Lithobates pipiens) has undergone dramatic declines in population size and range over recent decades in western Canada and the United States. In British Columbia, only a single population remains at the Creston Valley Wildlife Management Area. Yet, the continuing viability of this population is uncertain. In this paper, t...

Given widespread biodiversity declines, there is an urgent need to ensure that conservation interventions are working. Yet, evidence regarding the effectiveness of conservation actions is often lacking. Using a case study of 208 terrestrial species listed as Endangered in Canada, we conducted a literature review to collate the evidence base on cons...

The rapid transformation and pollution of ecosystems have severely impacted biodiversity. Specifically, anthropogenic activities have imposed adverse effects on amphibians, with evidence suggesting that these activities alter parasite and pathogen interactions within their hosts. To investigate these interactions in areas affected by different anth...

Western palearctic salamander susceptibility to the skin disease caused by the amphibian chytrid fungus Batrachochytrium salamandrivorans (Bsal) was recognized in 2014, eliciting concerns for a potential novel wave of amphibian declines following the B. dendrobatidis (Bd) chytridiomycosis global pandemic. Although Bsal had not been detected in Nort...

Systematic conservation planning is a framework that has been developed over the past decade to prioritize the management of key habitats and conserve biodiversity values. Artificial intelligence has been proposed to operate within this framework by using computer algorithms based on an objective function to identify and prioritize protected area n...

The world's reptiles and amphibians are experiencing dramatic and ongoing losses in biodiversity, changes that can have substantial effects on ecosystems and human health. In 2022, the first Global Amphibian and Reptile Disease Conference was held, using One Health as a guiding principle. The conference showcased knowledge on numerous reptile and a...

Declines in amphibian populations led to the implementation of conservation breeding programs (captive breeding and reintroduction) to prevent their extinction. However, the success of these programs is largely contingent upon the survival of the released tadpoles or metamorphosed individuals, making it imperative to assess the suitability and qual...

Documenting biodiversity, species occurrence, and species status require reliable monitoring techniques, but the complex life history and cryptic behavior of many anurans create challenges for conventional monitoring approaches. Environmental DNA (eDNA) surveys are a promising alternative (or complement) to conventional anuran monitoring, but their...

Chytridiomycosis is affecting amphibians worldwide, causing the decline and extinction of several amphibian populations. The disease is caused by the fungus Batrachochytrium dendrobatidis (Bd), a multihost pathogen living in freshwater habitats. While several environmental factors have been associated with the prevalence of Bd and its virulence, th...

The key role of symbiotic skin bacteria communities in amphibian resistance to emerging pathogens is well recognized, but factors leading to their dysbiosis are not fully understood. In particular, the potential effects of population translocations on the composition and diversity of hosts' skin microbiota have received little attention, although s...

In response to the current worldwide amphibian extinction crisis, conservation instances have encouraged the establishment of ex-situ collections for endangered species. The resulting assurance populations are managed under strict biosecure protocols, often involving artificial cycles of temperature and humidity to induce active and overwintering p...

Adult mortality is often the most sensitive vital rate affecting at‐risk wildlife populations. Therefore, road ecology studies often focus on adult mortality despite the possibility for roads to be hazardous to juvenile individuals during natal dispersal. Failure to quantify concurrent variation in mortality risk and population sensitivity across d...

Environmental DNA (eDNA) monitoring is rapidly becoming an established approach for detecting the presence of aquatic organisms and may also be useful for indexing or estimating species abundance. However, the link between eDNA concentration and abundance of individuals (i.e., density or biomass) remains tenuous and may vary widely across species a...

Despite the documented effects on human and animal health, particles smaller than 0.1 µm in diameter found in soils, sediments, and the atmosphere remain unregulated. Yet, cerium and titanium oxide nanoparticles associated with traffic increase mortality, cause behavioral changes, and inhibit the growth in amphibians. Mites of the genus Hannemania...

In an era where emerging infectious diseases are a serious threat to biodiversity, epidemiological patterns need to be identified, particularly the complex mechanisms driving the dynamics of multi-host pathogens in natural communities. Many amphibian species have faced unprecedented population declines associated with diseases. Yet, specific proces...

Chytridiomycosis, a primary disease driving widespread and unprecedented amphibian declines, is caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd). Tracking Bd through space and time requires monitoring protocols that efficiently and reliably assess pathogen prevalence and intensity, which in turn requires an understanding of environ...

Roads are one of the most prevalent threats to wildlife because they fragment landscapes and increase mortality. In response to the threat of roads to population persistence, road-effect mitigation strategies are increasingly common, typically as a combination of exclusion fencing to reduce mortality and crossing structures to enhance connectivity....

Dispersal following metamorphosis is critical for sustaining anuran metapopulations. Mink Frog (Lithobates septentrionalis) is a primarily aquatic species that is common in eastern Canada. The species is not well studied, and little is known about the terrestrial dispersal of recently metamorphosed individuals. Here we present our observations on t...

Animals use color both to conceal and signal their presence, with patterns that match the background, disrupt shape recognition, or highlight features important for communication. The forms that these color patterns take are responses to the visual systems that observe them and the environments within which they are viewed. Increasingly, however, t...

Mass mortality events (MMEs) can remove up to 90% of individuals in a population and are especially damaging to population viability of long-lived species with slow life histories. Our goal was to elucidate the cause(s) of a MME of 53 Blanding’s Turtles (Emydoidea blandingii (Holbrook, 1838)), a globally endangered species, in a protected area. We...

Ranaviruses are large nucleocytoplasmic DNA viruses that infect ectothermic vertebrates. Here we report the results of a scientometric analysis of the field of ranavirology for the last 10 years. Using bibliometric tools we analyse trends, identify top publications and journals, and visualise the ranavirus collaboration landscape. The Web of Scienc...

Roads are one of the most severe threats to wildlife globally because of their pervasive and linear nature. Despite considerable attention afforded to road-effects on animals generally, little information is available concerning the specific impacts of road widening, also known as twinning or highway expansion. To address this gap, we monitored the...

Ranaviruses have been associated with rising numbers of mass die-offs in amphibian populations around the globe. However, most studies on ranaviruses to date focused on larval amphibians. To assess the role of postmetamorphic amphibians in the epidemiology of ranaviruses and to determine the role of viral immune-suppression genes, we performed a ba...

Pathogen-induced population declines and extinction events have been recognized as main threats to amphibian species around the globe. However, the ecological drivers underlying epidemiological patterns are still poorly understood. In an attempt to assess the current knowledge on the ecological drivers of amphibian diseases, we identified 832 peer-...

Emerging infectious diseases are responsible for declines in wildlife populations around the globe. Mass mortality events associated with emerging infectious diseases are often associated with high number of infected individuals (prevalence) and high pathogen loads within individuals (intensity). At the landscape scale, spatial and temporal variati...

The negative effects of roads on wildlife have been well studied, and their mitigation is considered of critical importance to conservation. Mitigation of these threats commonly incorporates exclusion fencing and landscape connectivity structures, but the mechanics of mitigation success and species-specific responses are poorly understood. Eastern...

Amphibian populations are declining worldwide, and these declines have been linked to a number of anthropogenic factors, including disease. Among the pathogens associated with amphibian mortality, ranaviruses have caused massive die-offs across continents. In North America, frog virus 3 (FV3) is a widespread ranavirus that can infect wild and capti...

Significant advances have been made to minimize the detrimental effects of roads on wildlife, but little is known about unintended negative consequences of mitigation strategies. Here, we present observations of adverse effects on herpetofauna of exclusion fencing at Presqu’ile Provincial Park, Ontario. A total of 15 individuals (one salamander, ni...

Frog virus 3 (FV3) and FV3-like ranaviruses can infect a variety of cold-blooded aquatic species and present a primary threat to amphibians across the globe. Previous studies of FV3-like viruses have largely investigated higher-level phylogenetic distinctions of these pathogens via portions of the conserved major protein (MCP), and the putative vir...

Ranaviruses have been associated with rising numbers of mass die-offs in amphibian populations globally. With life-stages occupying different environments and presenting distinct physiologies, amphibian of different ages are likely to play an important role in pathogen persistence. To assess the potential role of post-metamorphic amphibians as a Ra...

Investigation of mortalities in isolated wild amphibian populations presents diagnostic difficulties that can hinder reaching a definitive diagnosis for the cause of death. Disease can only be diagnosed when pathogen presence (e.g. PCR) is linked to tissue lesions (histopathology) in the host. We report a two-site outbreak of ranavirosis in wild an...

Research on the amphibian skin microbiota has focused on identifying bacterial taxa that deter a pathogenic chytrid fungus, and on describing patterns of microbiota variation. However, it remains unclear how environmental variation affects amphibian skin bacterial communities, and whether the overall functional diversity of the amphibian skin micro...

Freshwater turtles are one of the most imperilled groups of vertebrates globally, and roads have been associated with their decline. Although roads are typically viewed as an imminent threat to population persistence, because of direct mortality and increased landscape fragmentation, we argue that they are an important sampling tool for collecting...

The mitigation of road-effects on wildlife, especially road mortality and habitat fragmentation, has become increasingly common in the last 20 years. However, exclusion fencing and habitat connectivity structures can be very costly and several questions remain regarding how to best determine locations that will optimize mitigation success. Based on...

Context Amphibians are particularly susceptible to the effects of habitat loss and fragmentation. The construction and use of roads is among the most common sources of habitat fragmentation and can lead to serious population declines. Unused resource access roads, such as those formerly used for logging, can still negatively impact salamanders and...

Pollution can affect wildlife directly through toxicity and indirectly through changes in biotic and abiotic factors, however, how these mechanisms interact in affecting free-ranging animals remains poorly understood. By examining effects on individual fitness proxies, we aimed to determine the mechanisms behind documented amphibian and reptile dec...

Pollinating insects are vital to the survival of many primary producers in terrestrial ecosystems, as up to 80–85 % of the world’s flowering plants require pollinators for reproduction. Over the last few decades however, numerous pollinating insect populations have declined substantially. The causes of these declines are multifaceted and synergisti...

Transmission is a central feature of pathogen fitness and influences host population dynamics. The form and magnitude of transmission rates determine whether a pathogen establishes itself in a host population and the proportion of a population that becomes infected. While the effects of environmental variation on pathogen transmission dynamics have...

Trace metals can have subtle, yet chronic impacts on organisms by inducing physiological stress that reduces their survival or impedes their ability to tolerate additional environmental stressors. However, toxicity literature indicates that aquatic organisms react differently to trace metals depending on the environments in which they reside. The o...

Aim Where post‐glacial colonization and founder events are numerous, peripheral populations tend to have reduced genetic diversity as compared to their centrally located counterparts. Such decrease in genetic variability can limit their potential to adapt to changes in their environment. At northern latitudes for instance, populations are often liv...

Amphibian populations are at risk of adverse impacts from roads and traffic. Roads constructed in the vicinity of wetlands and streams often interrupt amphibian movement pathways and can prevent individuals from accessing critical habitats. High numbers of amphibians are either deterred from crossing or killed by traffic, contributing to population...

Emissions from smelting not only contaminate water and soil with metals, but also induce extensive forest dieback and changes in resource availability and microclimate. The relative effects of such co-occurring stressors are often unknown, but this information is imperative in developing targeted restoration strategies. We assessed the role and rel...

Roadways pose serious threats to animal populations. The installation of roadway mitigation measures is becoming increasingly common, yet studies that rigorously evaluate the effectiveness of these conservation tools remain rare. A highway expansion project in Ontario, Canada included exclusion fencing and ecopassages as mitigation measures designe...

Infections by the fungal pathogen Batrachochytrium dendrobatidis (Bd) and members of the genus Ranavirus (Rv) are increasingly reported as significant determinants of amphibian population die-offs. The complexity associated with their transmission and spatial distribution leads to an increase in demand for comprehensive reporting systems and global...

The context-dependent investigations of host–pathogen genotypic interactions, where environmental factors are explicitly incorporated, allow the assessment of both coevolutionary history and contemporary ecological influences. Such a functional explanatory framework is particularly valuable for describing mortality trends and identifying drivers of...

Frog virus 3 (FV3) is the type species of the genus Ranavirus, and in the past few decades, FV3 infections have resulted in considerable morbidity and mortality in a range of wild and cultivated amphibian species in the Americas, Europe, and Asia. The reasons for the pathogenicity of FV3 are not well understood. We investigated three FV3 isolates d...

Conservation biology integrates multiple disciplines to expand the ability to identify threats to populations and develop mitigation for these threats. Road ecology is a branch of conservation biology that examines interactions between wildlife and roadways. Although the direct threats of road mortality and habitat fragmentation posed by roads have...

Population level response to hypoxia has become an issue of global significance because of increased frequency and intensity of hypoxic events worldwide, and the potential for global warming to exacerbate hypoxic stress. In this study, we sequenced two nuclear intronic regions and a single mitochondrial region across seven populations of the Africa...