Brian Gratwicke

Brian Gratwicke
Smithsonian Institution · Smithsonian Conservation Biology Institute

About

96
Publications
62,124
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4,518
Citations

Publications

Publications (96)
Article
Full-text available
Characterizing the population density of species is a central interest in ecology. Eastern North America is the global hotspot for biodiversity of plethodontid salamanders, an inconspicuous component of terrestrial vertebrate communities, and among the most widespread is the eastern red-backed salamander, Plethodon cinereus. Previous work suggests...
Book
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As the most threatened vertebrate class on earth, amphibians are at the forefront of the biodiversity crisis, with the recognition of global amphibian declines and extinctions dating back several decades now. The current Amphibian Conservation Action Plan is adopting two strategies to address the goal of the amelioration of the amphibian crisis: th...
Article
Full-text available
Phylosymbiosis is an association between host-associated microbiome composition and host phylogeny. This pattern can arise via the evolution of host traits, habitat preferences, diets, and the co-diversification of hosts and microbes. Understanding the drivers of phylosymbiosis is vital for modelling disease-microbiome interactions and manipulating...
Preprint
Full-text available
Phylosymbiosis is an association between host-associated microbiome and host phylogeny. This pattern can arise via evolution of host traits, habitat preferences, diets, and co-diversification of hosts and microbes. Understanding the drivers of phylosymbiosis is vital for modelling disease-microbiome interactions and manipulating microbiomes in mult...
Article
Full-text available
Variable harlequin frogs Atelopus varius have declined significantly throughout their range as a result of infection with the fungal pathogen Batrachochytrium den-drobatidis (Bd). The Panama Amphibian Rescue and Conservation Project maintains an ex situ population of this Critically Endangered species. We conducted a release trial with surplus capt...
Article
Full-text available
ARTICLE Ongoing harlequin toad declines suggest the amphibian extinction crisis is still an emergency Biodiversity loss is extreme in amphibians. Despite ongoing conservation action, it is difficult to determine where we stand in overcoming their extinction crisis. Among the most threatened amphibians are the 131 Neotropical harlequin toads. Many o...
Article
Full-text available
Systematic assessments of species extinction risk at regular intervals are necessary for informing conservation action1,2. Ongoing developments in taxonomy, threatening processes and research further underscore the need for reassessment3,4. Here we report the findings of the second Global Amphibian Assessment, evaluating 8,011 species for the Inter...
Article
Full-text available
Systematic assessments of species extinction risk at regular intervals are necessary for informing conservation action1,2. Ongoing developments in taxonomy, threatening processes and research further underscore the need for reassessment3,4. Here we report the findings of the second Global Amphibian Assessment, evaluating 8,011 species for the Inter...
Article
Full-text available
The endangered Limosa harlequin frog Atelopus limosus has experienced significant chytridiomycosis-related declines, but has been successfully bred in captivity as part of the Panama Amphibian Rescue and Conservation Project. We conducted the first Atelopus release trial using 83 captive-bred A. limosus, and monitored individuals as they transition...
Article
The endangered Limosa harlequin frog Atelopus limosus has experienced significant chytridiomycosis-related declines, but has been successfully bred in captivity as part of the Panama Amphibian Rescue and Conservation Project. We conducted the first Atelopus release trial using 83 captive-bred A. limosus, and monitored individuals as they transition...
Article
Full-text available
The problem of global amphibian declines has prompted extensive research over the last three decades. Initially, the focus was on identifying and characterizing the extent of the problem, but more recently efforts have shifted to evidence-based research designed to identify best solutions and to improve conservation outcomes. Despite extensive accu...
Preprint
Full-text available
Anthropogenic biodiversity loss is extreme in amphibians. Despite ongoing conservation action, it is difficult to determine where we stand in overcoming their extinction crisis 1,2. Extinction risk is not equally distributed across amphibians 3-5. Among the most threatened amphibians are the 131 Neotropical harlequin toads (Atelopus), many of which...
Article
Full-text available
Dynamic interactions between host, pathogen and host-associated microbiome dictate infection outcomes. Pathogens including Batrachochytrium dendrobatidis (Bd) threaten global biodiversity, but conservation efforts are hindered by limited understanding of amphibian host, Bd and microbiome interactions. We conducted a vaccination and infection experi...
Chapter
This chapter evaluates the detrimental effects of exotic anurans on native biota and how those provide an important justification for the ways frogs matter relative to exotic species impacts. It is clear that in the fight to save frogs, context matters. The species, its ecology, the value systems of the people living alongside them, and the audienc...
Article
Full-text available
Many endangered amphibian species survive in captive breeding facilities, but there have been few attempts to reintroduce captive-born individuals to rebuild wild populations. We conducted a soft-release trial of limosa harlequin frogs, Atelopus limosus, which are highly susceptible to the amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd...
Article
Captive breeding to safeguard against extirpation in the wild is a practice for many animal groups. Animals in captivity experience reduced contact with natural substrates and other animals, and consume atypical diets that may alter naturally occurring microbial associations. Amphibian skin microbiomes are vital for amphibian health, protecting the...
Article
Full-text available
Mucosal defenses are crucial in animals for protection against pathogens and predators. Host defense peptides (antimicrobial peptides, AMPs) as well as skin-associated microbes are key components of mucosal immunity, particularly in amphibians. We integrate microbiology, molecular biology, network-thinking, and proteomics to understand how host and...
Article
Full-text available
We designed two probiotic treatments to control chytridiomycosis caused by Batrachochytrium dendrobatidis (Bd) on infected Panamanian golden frogs (Atelopus zeteki), a species that is thought to be extinct in the wild due to Bd. The first approach disrupted the existing skin microbe community with antibiotics then exposed the frogs to a core golden...
Article
Cold-adapted hellbender salamanders that inhabit cool mountain streams are expected to fare poorly under warmer projected climate scenarios. This study investigated the physiological consequences of long-term, naturalistic temperature variation on juvenile hellbenders under simulated current and warmer (+1.6 C) climates vs. controlled steady temper...
Article
Full-text available
Severe Perkinsea infection is an emerging disease of amphibians, specifically tadpoles. Disease presentation correlates with liver infections of a subclade of Perkinsea (Alveolata) protists, named Pathogenic Perkinsea Clade (PPC). Tadpole mortality events associated with PPC infections have been reported across North America, from Alaska to Florida...
Article
Full-text available
The disease chytridiomycosis caused by the fungus Bd has devastated amphibian populations worldwide. Functional genomic contributions to host susceptibility remain enigmatic and vary between species and populations. We conducted experimental Bd infections in Rana yavapaiensis, a species with intraspecific variation in chytridiomycosis susceptibilit...
Article
Full-text available
Spindly leg syndrome (SLS) is a relatively common musculoskeletal abnormality associated with captive-rearing of amphibians with aquatic larvae. We conducted an experiment to investigate the role of environmental calcium and phosphate in causing SLS in tadpoles. Our 600-tadpole experiment used a fully-factorial design, rearing Atelopus varius tadpo...
Article
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Lambert et al . question our retrospective and holistic epidemiological assessment of the role of chytridiomycosis in amphibian declines. Their alternative assessment is narrow and provides an incomplete evaluation of evidence. Adopting this approach limits understanding of infectious disease impacts and hampers conservation efforts. We reaffirm th...
Article
Captive breeding programs are a valuable conservation strategy, particularly when integrated with research goals. Panamanian Harlequin frogs (genus Atelopus) serve as a case study for integrating captive breeding and research goals because they have experienced drastic chytridiomycosis-related declines and have large captive populations. Captive br...
Article
Full-text available
The demise of amphibians? Rapid spread of disease is a hazard in our interconnected world. The chytrid fungus Batrachochytrium dendrobatidis was identified in amphibian populations about 20 years ago and has caused death and species extinction at a global scale. Scheele et al. found that the fungus has caused declines in amphibian populations every...
Article
Full-text available
Spindly Leg Syndrome (SLS) is a persistent animal welfare issue associated with the rearing of amphibians in captivity. We conducted two experiments to investigate the effects of diet, water composition and overfeeding on prevalence of SLS in newly metamorphosed harlequin frogs (Atelopus spp.). In our first experiment, we offered 400 full-sibling t...
Data
Periphyton collection from historical Atelopus habitat. Details of attempted collection and nutritional analysis of diatoms and algae growing in Atelopus habitat. (DOCX)
Data
Experimental data (excel file). Tab 1: Raw results data from experiment 1. Tab 2: Raw results data from experiment 2. (XLSX)
Data
Brand information. Account of brands, makes and models used in this experiment. (DOCX)
Article
Full-text available
A chytridiomycosis outbreak from Batrachochytrium dendrobatidis ( Bd) in a mixed-species plethodontid salamander exhibit resulted in four green salamander ( Aneides aeneus) deaths. One green salamander died before treatment, and three died during treatment with daily 0.005% itraconazole baths. All salamanders had evidence of severe Bd infections vi...
Article
Full-text available
Symbiotic bacteria can produce secondary metabolites and volatile compounds that contribute to amphibian skin defense. Some of these symbionts have been used as probiotics to treat or prevent the emerging disease chytridiomycosis. We examined 20 amphibian cutaneous bacteria for the production of prodigiosin or violacein, brightly colored defense co...
Article
Full-text available
We engaged pet salamander owners in the United States to screen their animals for two amphibian chytrid fungal pathogens Batrachochytrium dendrobatidis (Bd) and B. salamandrivorans (Bsal). We provided pet owners with a sampling kit and instructional video to swab the skin of their animals. We received 639 salamander samples from 65 species by mail,...
Article
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Sodium hypochlorite (NaOCl) is the active ingredient in household bleach and is commonly used as a disinfectant to clean equipment contaminated by the amphibian pathogen Batrachochytrium dendrobatidis (Bd) in lab husbandry and field studies. We conducted a series of replicated exposure trials using a single Global Pandemic Lineage Bd isolate from P...
Data
Optical density changes in relation to bleach concentration and exposure time. Excel file containing experimental data with bleach concentration, exposure time, starting and final optical density information used to draw Fig 1. (XLSX)
Article
Full-text available
I have always liked frogs. Iliked themsince before becoming a zoologist, and nothing Ihave had to learn about themsince has marred the attachment. Ilike "looks" offrogs and theiroutlook. And especially the way they get togetherin wet places on warmnights and sing about sex.
Article
Full-text available
Several biogeographic studies of salamanders have described relationships between salamander body size and climate. We specifically selected Plethodon cinereus as a widely distributed species that was well represented in museum collections to investigate the effects of warming climate on adult body size. We found a positive correlation between mean...
Article
Full-text available
The relationship between amphibian immune function and disease susceptibility is of primary concern given current worldwide declines linked to the pathogenic fungus Batrachochytrium dendrobatidis (Bd). We experimentally infected lowland leopard frogs (Lithobates yavapaiensis) with Bd to test the hypothesis that infection causes physiological stress...
Article
Full-text available
Amphibians around the world are declining from threats that cannot currently be mitigated, making it impossible to safeguard some species in their natural habitats. Amphibians in the mountainous neotropics are one example where severe disease-related declines prompted calls for the establishment of captive assurance colonies to avoid extinctions. W...
Article
Full-text available
Symbiotic microbes can dramatically impact host health and fitness, and recent research in a diversity of systems suggests that different symbiont community structures may result in distinct outcomes for the host. In amphibians, some symbiotic skin bacteria produce metabolites that inhibit the growth of Batrachochytrium dendrobatidis (Bd), a cutane...
Article
Full-text available
We have established ex situ assurance colonies of two endangered Panamanian harlequin frogs, Atelopus certus and Atelopus glyphus, but observed that males fought with each other when housed as a group. Housing frogs individually eliminated this problem, but created space constraints. To evaluate the potential stress effects from aggressive interact...
Article
Full-text available
Microbial communities can augment host immune responses and probiotic therapies are under development to prevent or treat diseases of humans, crops, livestock, and wildlife including an emerging fungal disease of amphibians, chytridiomycosis. However, little is known about the stability of host-associated microbiota, or how the microbiota is struct...
Article
Full-text available
Ectothermic species living in temperate regions can experience rapid and potentially stressful changes in body temperature driven by abrupt weather changes. Yet, among amphibians, the physiological impacts of short-term temperature variation are largely unknown. Using an ex situ population of Cryptobranchus alleganiensis, an aquatic North American...
Chapter
This chapter describes and illustrates the issues surrounding wildlife trade policies. Wildlife trades are complex and heterogeneous, requiring different management approaches although the issues discussed may be common. It should be possible to develop a suite of investigations based on the issues raised in this chapter to estimate the impacts of...
Article
Full-text available
Populations of native Panamanian golden frogs (Atelopus zeteki) have collapsed due to a recent chytridiomycosis epidemic. Reintroduction efforts from captive assurance colonies are unlikely to be successful without the development of methods to control chytridiomycosis in the wild. In an effort to develop a protective treatment regimen, we treated...
Article
Full-text available
Herpetologists often complain that, despite amphibians' being one of the most threatened vertebrate classes, there is a dearth of funding and capacity to tackle the global crisis afflicting them. We compared the average funding per species listed under the US Endangered Species Act (ESA) to quantify funding favoritism across vertebrate classes in t...
Article
Making effective investments through grantees in order to sustain and recover wild tiger populations from the vantage point of an organization based in Washington DC (USA) is a high risk endeavor for two reasons: grantees may fail to produce the outputs or deliverables promised; and even if the outputs are generated as promised, grantees may fail t...
Chapter
Full-text available
The most recent analysis of tiger habitats suggests that tigers now occupy only 7% of their historic range and the area they occupy has decreased by as much as 40% in the past decade. The understanding of wild tiger populations and their habitats in many of the range states has improved substantially. Newer statistically robust estimates of tiger d...
Conference Paper
Background/Question/Methods Recent declines of amphibian populations are associated with the disease chytridiomycosis, which is caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd). Cutaneous bacteria isolated from the amphibian species Plethodon cinereus and Rana muscosa inhibit the growth of Bd in vitro. In this study, the cutaneous b...
Article
Full-text available
Fish migrations into the streams of seasonally-flooded depressions (or dambos) that cover the central plateaus of Africa are a well-known phenomenon to scientists and lay people alike. However, the factors causing seasonal migrations are poorly understood and most scientific references to them are anecdotal, lacking rigorous description. Fish migra...
Article
There have been surprisingly few analyses of how the international trade in amphibians for food affects the conservation status of this group. We analyzed information from the UN Commodity Trade Statistics Database and found that, by volume, Indonesia supplied nearly half of the animals entering the world's US$40 million per year international frog...
Data
Demographic characteristics of respondents (0.02 MB DOC)