Limits...
Measuring the meltdown: drivers of global amphibian extinction and decline.

Sodhi NS, Bickford D, Diesmos AC, Lee TM, Koh LP, Brook BW, Sekercioglu CH, Bradshaw CJ - PLoS ONE (2008)

Bottom Line: We present the largest global analysis of roughly 45% of known amphibians (2,583 species) to quantify the influences of life history, climate, human density and habitat loss on declines and extinction risk.Elevated habitat loss and human densities are also correlated with high threat risk.These empirical results show that amphibian species with restricted ranges should be urgently targeted for conservation.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, National University of Singapore, Singapore, Singapore.

ABSTRACT
Habitat loss, climate change, over-exploitation, disease and other factors have been hypothesised in the global decline of amphibian biodiversity. However, the relative importance of and synergies among different drivers are still poorly understood. We present the largest global analysis of roughly 45% of known amphibians (2,583 species) to quantify the influences of life history, climate, human density and habitat loss on declines and extinction risk. Multi-model Bayesian inference reveals that large amphibian species with small geographic range and pronounced seasonality in temperature and precipitation are most likely to be Red-Listed by IUCN. Elevated habitat loss and human densities are also correlated with high threat risk. Range size, habitat loss and more extreme seasonality in precipitation contributed to decline risk in the 2,454 species that declined between 1980 and 2004, compared to species that were stable (n = 1,545) or had increased (n = 28). These empirical results show that amphibian species with restricted ranges should be urgently targeted for conservation.

Show MeSH

Related in: MedlinePlus

Major variables affecting amphibian species threat (yellow arrows) and decline (blue arrows) risk.Arrow width corresponds to amount of threat or decline risk (approximately related to the per cent deviance explained) described by each attribute (Tables 1 and S5–S6). The major determinant of both threat (IUCN Red-Listed) and decline risk is range size (stronger effect for threat risk), followed by body size (allometry). Certain life history characteristics (life habit, reproductive cycle and mode) also weakly affect decline risk. Environmental conditions such as mean ambient temperature, temperature seasonality, precipitation seasonality, habitat loss and human density also explain a small amount of variation in both threat and decline risk.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2238793&req=5

pone-0001636-g001: Major variables affecting amphibian species threat (yellow arrows) and decline (blue arrows) risk.Arrow width corresponds to amount of threat or decline risk (approximately related to the per cent deviance explained) described by each attribute (Tables 1 and S5–S6). The major determinant of both threat (IUCN Red-Listed) and decline risk is range size (stronger effect for threat risk), followed by body size (allometry). Certain life history characteristics (life habit, reproductive cycle and mode) also weakly affect decline risk. Environmental conditions such as mean ambient temperature, temperature seasonality, precipitation seasonality, habitat loss and human density also explain a small amount of variation in both threat and decline risk.

Mentions: We also identified environmental determinants (local context) of threat risk, after controlling for the conditional life history traits of geographic range and body size (Table 1b). There was some support for weak effects of mean annual temperature, annual temperature seasonality and annual precipitation seasonality (the two top-ranked models accounted for 0.354 and 0.267 of the wBIC, respectively; Table 1b). Threat risk increased with more pronounced seasonality in temperature, precipitation, habitat loss and human density, but declined with increasing ambient temperature (Fig. 1). Although not completely intuitive, these results agree broadly with known environmental and historical constraints on amphibian distributions [19] and suggest that multiple variables may threaten amphibians. Thus there is an urgency with which amphibian restoration efforts must target regions of high amphibian threat risk, given that anthropogenic climate change is known to exacerbate amphibian extinction trends [1].


Measuring the meltdown: drivers of global amphibian extinction and decline.

Sodhi NS, Bickford D, Diesmos AC, Lee TM, Koh LP, Brook BW, Sekercioglu CH, Bradshaw CJ - PLoS ONE (2008)

Major variables affecting amphibian species threat (yellow arrows) and decline (blue arrows) risk.Arrow width corresponds to amount of threat or decline risk (approximately related to the per cent deviance explained) described by each attribute (Tables 1 and S5–S6). The major determinant of both threat (IUCN Red-Listed) and decline risk is range size (stronger effect for threat risk), followed by body size (allometry). Certain life history characteristics (life habit, reproductive cycle and mode) also weakly affect decline risk. Environmental conditions such as mean ambient temperature, temperature seasonality, precipitation seasonality, habitat loss and human density also explain a small amount of variation in both threat and decline risk.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2238793&req=5

pone-0001636-g001: Major variables affecting amphibian species threat (yellow arrows) and decline (blue arrows) risk.Arrow width corresponds to amount of threat or decline risk (approximately related to the per cent deviance explained) described by each attribute (Tables 1 and S5–S6). The major determinant of both threat (IUCN Red-Listed) and decline risk is range size (stronger effect for threat risk), followed by body size (allometry). Certain life history characteristics (life habit, reproductive cycle and mode) also weakly affect decline risk. Environmental conditions such as mean ambient temperature, temperature seasonality, precipitation seasonality, habitat loss and human density also explain a small amount of variation in both threat and decline risk.
Mentions: We also identified environmental determinants (local context) of threat risk, after controlling for the conditional life history traits of geographic range and body size (Table 1b). There was some support for weak effects of mean annual temperature, annual temperature seasonality and annual precipitation seasonality (the two top-ranked models accounted for 0.354 and 0.267 of the wBIC, respectively; Table 1b). Threat risk increased with more pronounced seasonality in temperature, precipitation, habitat loss and human density, but declined with increasing ambient temperature (Fig. 1). Although not completely intuitive, these results agree broadly with known environmental and historical constraints on amphibian distributions [19] and suggest that multiple variables may threaten amphibians. Thus there is an urgency with which amphibian restoration efforts must target regions of high amphibian threat risk, given that anthropogenic climate change is known to exacerbate amphibian extinction trends [1].

Bottom Line: We present the largest global analysis of roughly 45% of known amphibians (2,583 species) to quantify the influences of life history, climate, human density and habitat loss on declines and extinction risk.Elevated habitat loss and human densities are also correlated with high threat risk.These empirical results show that amphibian species with restricted ranges should be urgently targeted for conservation.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, National University of Singapore, Singapore, Singapore.

ABSTRACT
Habitat loss, climate change, over-exploitation, disease and other factors have been hypothesised in the global decline of amphibian biodiversity. However, the relative importance of and synergies among different drivers are still poorly understood. We present the largest global analysis of roughly 45% of known amphibians (2,583 species) to quantify the influences of life history, climate, human density and habitat loss on declines and extinction risk. Multi-model Bayesian inference reveals that large amphibian species with small geographic range and pronounced seasonality in temperature and precipitation are most likely to be Red-Listed by IUCN. Elevated habitat loss and human densities are also correlated with high threat risk. Range size, habitat loss and more extreme seasonality in precipitation contributed to decline risk in the 2,454 species that declined between 1980 and 2004, compared to species that were stable (n = 1,545) or had increased (n = 28). These empirical results show that amphibian species with restricted ranges should be urgently targeted for conservation.

Show MeSH
Related in: MedlinePlus