Widespread amphibian declines from epidemic disease driven by global warming

Golden Toad Laboratory for Conservation, Monteverde Cloud Forest Preserve and Tropical Science Center, Santa Elena, Puntarenas 5655-73, Costa Rica.
Nature (Impact Factor: 41.46). 01/2006; 439(7073):161-7. DOI: 10.1038/nature04246
Source: PubMed


As the Earth warms, many species are likely to disappear, often because of changing disease dynamics. Here we show that a recent mass extinction associated with pathogen outbreaks is tied to global warming. Seventeen years ago, in the mountains of Costa Rica, the Monteverde harlequin frog (Atelopus sp.) vanished along with the golden toad (Bufo periglenes). An estimated 67% of the 110 or so species of Atelopus, which are endemic to the American tropics, have met the same fate, and a pathogenic chytrid fungus (Batrachochytrium dendrobatidis) is implicated. Analysing the timing of losses in relation to changes in sea surface and air temperatures, we conclude with 'very high confidence' (> 99%, following the Intergovernmental Panel on Climate Change, IPCC) that large-scale warming is a key factor in the disappearances. We propose that temperatures at many highland localities are shifting towards the growth optimum of Batrachochytrium, thus encouraging outbreaks. With climate change promoting infectious disease and eroding biodiversity, the urgency of reducing greenhouse-gas concentrations is now undeniable.

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Available from: Luis A. Coloma
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    • "These interactions between environmental and genetic control are evident in the many field surveys of pathogen prevalence in wild populations (Burdon, 1977; Vercelli, 2004; Hunter, 2005). For example, models predict that Bd has a higher probability of occurrence at high elevations, where mean temperatures and cloud cover provide better (or ideal) conditions for its growth (Piotrowski et al., 2004; Pounds et al., 2006). However, not all high elevation sites appear to respond equally to Bd infection (Lips, 1998; La Marca et al., 2005; Brem and Lips, 2008; Kriger and Hero, 2008; Gründler et al., 2012). "
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    ABSTRACT: Environmental factors can limit the distribution of organisms if they are not able to respond through phenotypic plasticity or local adaptation. Batrachochytrium dendrobatidis (Bd) is a broadly distributed pathogen, which shows spatially patterned genotypic and phenotypic variation; however, information on the functional consequences of this variation on disease dynamics in natural hosts is limited. We genotyped and quantified variation in Bd phenotypes across an elevational gradient and quantified host infection dynamics at each site. All Bd strains were members of the global panzootic lineage yet differed in phenotype. We hypothesize that this phenotypic variance results from adaptive processes due to the interaction between pathogen, hosts, and environment. We detected a correlation between zoospore and zoosporangia sizes and a positive association between zoosporangia size and Bd prevalence. Given that Bd phenotype predicted disease status in our wild populations, we developed an index to identify critical environments where the fungus could be more deleterious.
    Full-text · Article · Apr 2016 · Fungal Ecology
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    • "We found that stream-breeding species with small clutches are especially sensitive to habitat alteration, which has not been previously reported.Cooper et al. (2008)found that clutch size is a significant component of geographical range size, whileHero et al. (2005)suggested that more fecund species might have greater potential to spread to new areas and occupy large geographical ranges. If larger clutches are related to larger ranges, higher dispersal ability and colonization success in amphibians, smaller clutches may render species more susceptible to stochastic events and anthropogenic activities, resulting in increased sensitivity to habitat alteration (Grafe et al., 2004;Pounds et al., 2006). Range size was a predictor of species vulnerability to habitat alteration , especially for pond breeders. "
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    ABSTRACT: Determining species extinction risk and its drivers is a major goal for conservation biology. The IUCN Red List is widely used for classifying extinction-risk and prioritizing conservation action. However, this system has been acknowledged as biased and complementary approaches are strongly recommended to achieve more reliable conclusions on conservation priorities. Species traits, often perceived as determinant for resiliency to disturbances, have been used to identify potentially vulnerable species, even when data are scarce (e.g. Data Deficient species). We provide an integrative and cost-effective framework for predicting species extinction-risk using data on 195 anurans from the Brazilian Cerrado. We used IUCN population trend and expert-perceived vulnerability to habitat alteration as response variables, to identify traits associated to increased extinction-risk. We used species traits, threat pressure and geographic range to determine which species and areas should have higher conservation priority. We found the IUCN extinction-risk to be underestimated, as many species categorized as LC or DD are actually sensitive and/or declining. We identified breeding site, habitat and clutch size as predictors of anuran extinction risk. We found that > 70% of the biome's anurans have major protection gaps, incurring in high extinction-risk. The southwest and central regions of the biome are the main hotspots for high extinction-risk species and should be prioritized for conservation. Our framework may be particularly valuable to assess extinction-risk and prioritize conservation action regarding less studied taxa and regions with high anthropogenic pressure, but weak government support and scarce funding.
    Full-text · Article · Mar 2016 · Biological Conservation
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    • "Amphibians are regarded as the most endangered class of vertebrates (Gibbons et al. 2000, Stuart et al. 2004), and their global decline is matter of great concern because of its consequences for species conservation and ecosystem function (Hocking & Babbitt 2014, Cortez-Gomes et al. 2015). The drivers of amphibian population declines are various and wellknown: habitat destruction, alteration and fragmentation; pollution; use of pesticides and fertilizers; direct capture; climate change; diseases; and the introduction of allochthonous species (Webb & Joss 1997, Kats & Ferrer 2003, Pounds et al. 2006, Cushman 2006, Mann et al. 2009). Due to their vulnerability, the European Union has included many native amphibian species in the Habitat Directive 92/43/EEC, in order to guarantee their protection by the establishment of protected areas: Sites of Community Importance (SCIs). "
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    ABSTRACT: The spread of non-native invasive species is among the factors thought to be responsible for the recent global declines in amphibian populations. In a Protected Natural Area of Local Interest in Tuscany, Italy, we tested approaches for preserving the local amphibian populations threatened by the presence of the red swamp crayfish Procambarus clarkii. The construction of artificial breeding ponds, with suitable vertical barriers, was initially effective in preventing the spread of the red swamp crayfish and created a source site for amphibians, in particular newt species. Unfortunately, five years after construction, the breeding sites were colonized by fish and crayfish, possibly due to the actions of members of the public.
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