Amphibian Decline or Extinction? Current Declines Dwarf Background Extinction Rate

McCallum, Malcolm L.

doi:10.1670/0022-1511(2007)41[483:adoecd]2.0.co;2

Cited by 232 publications

(160 citation statements)

References 38 publications

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“…Figures for caudatans are similar in relative terms (Materials and Methods). The anuran total to date is higher than previously reported values (2). Therefore, one could argue that the tallies might represent regional extirpations, taxonomic errors, and cases in which population crashes have not yet led to actual extinctions.…”

Section: Discussionmentioning

confidence: 62%

“…The IUCN threat categorization is widely used in studies of global and regional patterns (1)(2)(3)(4)(5).…”

Section: Extinction Probability Equationmentioning

confidence: 99%

“…amphibians | Bayesian methods | extinction rates | reptiles O btaining concrete estimates of extinction tallies for major taxonomic groups has proven to be elusive, with the literature veering between conservative counts based on thorough assessments of well-known species to much higher figures based on global-scale considerations of threat levels (1)(2)(3)(4)(5). Uncertainty is so great that, for example, the 2004 Global Amphibian Assessment (1) used by the International Union for the Conservation of Nature (IUCN) hazarded that anywhere between 9 and 122 amphibians might have gone extinct since 1980.…”

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confidence: 99%

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Current extinction rates of reptiles and amphibians

Alroy

2015

Proc. Natl. Acad. Sci. U.S.A.

221

143

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There is broad concern that a mass extinction of amphibians and reptiles is now underway. Here I apply an extremely conservative Bayesian method to estimate the number of recent amphibian and squamate extinctions in nine important tropical and subtropical regions. The data stem from a combination of museum collection databases and published site surveys. The method computes an extinction probability for each species by considering its sighting frequency and last sighting date. It infers hardly any extinction when collection dates are randomized and it provides underestimates when artificial extinction events are imposed. The method also appears to be insensitive to trends in sampling; therefore, the counts it provides are absolute minimums. Extinctions or severe population crashes have accumulated steadily since the 1970s and 1980s, and at least 3.1% of frog species have already disappeared. Based on these data and this conservative method, the best estimate of the global grand total is roughly 200 extinctions. Consistent with previous results, frog losses are heavy in Latin America, which has been greatly affected by the pathogenic chytrid fungus Batrachochytrium dendrobatidis. Extinction rates are now four orders-of-magnitude higher than background, and at least another 6.9% of all frog species may be lost within the next century, even if there is no acceleration in the growth of environmental threats.

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Section: Discussionmentioning

confidence: 62%

“…The IUCN threat categorization is widely used in studies of global and regional patterns (1)(2)(3)(4)(5).…”

Section: Extinction Probability Equationmentioning

confidence: 99%

mentioning

confidence: 99%

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Current extinction rates of reptiles and amphibians

Alroy

2015

Proc. Natl. Acad. Sci. U.S.A.

221

143

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“…The present extinction rate of this group is thought to be greater than its basal extinction rate (McCallum 2007). The process of anuran population declines involves multiple factors, including habitat loss, pollution, UV radiation, biological invasions, diseases, and climate change (Alford and Richards 1999).…”

Section: Introductionmentioning

confidence: 99%

Potential Effects of Climate Change on the Distribution of an Endangered Species: Melanophryniscus montevidensis (Anura: Bufonidae)

Toranza¹,

Maneyro²

2014

Phyllomedusa

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Potential effects of climate change on the distribution of an endangered species:Melanophryniscus montevidensis (Anura: Bufonidae). Species distributions are linked with climate. Among the effects predicted by the Intergovernmental Panel on Climate Change are changes in precipitation patterns and increases in mean temperatures-factors potentially having a major impact on threatened, rare, and endemic species. Using models to forecast possible changes in the distributions of different species under different climatechange scenarios, we can identify probable impacts on species and build effective conservation strategies. We modeled the effects of two climate-change scenarios on the geographical distribution of the regionally endemic bufonid, Melanophryniscus montevidensis, categorized as vulnerable by the IUCN and as endangered by the Uruguayan Red List of amphibians. Ecological niche models were generated to describe the present and possible future distributions of this species in 2050 and 2080, given severe (A2) and moderate (B2) climatic changes. Legacy data for M. montevidensis were obtained from Uruguayan biocollections and climate data were acquired from the WorldClim database. At present, M. montevidensis could occur along the Atlantic Uruguayan coast and a small section of the southern Brazilian coast. However, changes in climate may lead to a loss of suitable environmental conditions for this toad; thus, this endangered species is vulnerable and in urgent need of protection.Keywords: amphibians, geographical distribution, niche models, threatened species, Uruguay. 98Phyllomedusa -12(2), December 2013 Resumen Efectos potenciales del cambio climático sobre la distribución de una especie amenazada: Melanophryniscus montevidensis (Anura: Bufonidae). La distribución de las especies está relacionada con el clima. Entre los efectos predichos por el Panel Intergubernamental de Cambio Climático, se encuentran los cambios en los patrones de precipitación y los aumentos en la temperatura media global. Estos factores tienen un impacto mayor en especies amenazadas, raras o endémicas. Usando modelos para predecir posibles cambios en la distribución de especies bajo diferentes escenarios de cambios climático, podemos identificar probables impactos sobre las especies y construir estrategias efectivas de conservación. Modelamos los efectos de dos escenarios de cambio climático en la distribución geográfica de un bufónido regionalmente endémico, Melanophryniscus montevidensis, categorizado como Vulnerable por la UICN, y como amenazado según la Lista Roja de Anfibios de Uruguay. Fueron generados modelos de nicho para describir la distribución presente y futura en 2050 y 2080, bajo los escenarios A2 (severo) y B2 (moderado). Los registros fueron obtenidos de las principales colecciones del país y los datos climáticos se tomaron de la base de datos WorldClim. Actualmente, M. montevidensis podría encontrarse en la costa Atlántica de Uruguay, y una pequeña parte de la costa del sureste de Brasil. Sin embargo, los cambi...

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“…Amphibian populations are declining rapidly worldwide due to anthropogenic causes such as habitat loss, pollution, collection for the pet trade, introduction of invasive species and the spread of disease (Stuart et al, 2004;McCallum, 2007;Sodhi et al, 2008). As one of the global biodiversity hot spots, Madagascar is home to over 300 described species of frogs, 99% of which are endemic (Glaw Vences, 2007;Rakotoarison et al, 2017).…”

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confidence: 99%

Exploring non-invasive sampling of parasites by metabarcoding gastrointestinal nematodes in Madagascar frog species

Aivelo¹,

Harris²,

Cadle³

et al. 2018

bah

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The diversity of Anuran parasites is poorly surveyed, despite arguably being one of the most important threats to anuran populations worldwide. Additionally, parasites also interact with a number of other stressors, such as invasive species, pollution, sedimentation and changing light conditions, caused by anthropogenic disturbance in natural habitats. We aimed to explore the use of metabarcoding, a new, non-invasive tool to survey the parasite assemblages in frogs in different environments facing different levels of anthropogenic pressure. We collected fecal samples from frogs across three different transects in Ranomafana National Park, located in southeastern Madagascar, and then used the 18S metabarcoding technique to identify nematode species from the collected fecal samples. We were able to find four different putative species, which were all identified to the genus level. In comparison to the literature on previous surveys done with traditional methods, the metabarcoding approach seems to provide similar diversity estimates and taxonomical accuracy. Our results suggest that non-invasive sampling and metabarcoding can provide a suitable tool for intestinal parasite surveys in anuran host populations.

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Amphibian Decline or Extinction? Current Declines Dwarf Background Extinction Rate

Cited by 232 publications

References 38 publications

Current extinction rates of reptiles and amphibians

Current extinction rates of reptiles and amphibians

Potential Effects of Climate Change on the Distribution of an Endangered Species: Melanophryniscus montevidensis (Anura: Bufonidae)

Exploring non-invasive sampling of parasites by metabarcoding gastrointestinal nematodes in Madagascar frog species

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