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Measuring the meltdown: drivers of global amphibian extinction and decline - PubMed

  • ️Tue Jan 01 2008

Measuring the meltdown: drivers of global amphibian extinction and decline

Navjot S Sodhi et al. PLoS One. 2008.

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.

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Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Figure 1
Figure 1. 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.

Figure 2
Figure 2. Median geographic range sizes for various amphibian threat and decline categories.

Median (±95% confidence limits) log-transformed geographic range sizes for Red-Listed (threatened) versus non-threatened species, and for declining (assessed between 1980 and 2004) and non-declining (stable or increasing) species.

Figure 3
Figure 3. Predicted probabilities of population decline for the life history terms habit, spawning site, reproductive cycle, reproductive mode, presence/absence of parental care and fertilization type (derived from the nine-term model BS+RG+RG2+HB+SS+RC+RM+PC+FT based on the BIC-selected top-ranked model; see Table 2).

The observed extinction probability 95% confidence interval (dotted horizontal lines) was determined by a 10,000 iteration bootstrap of the probabilities predicted by the above model over 3,052 species. Changes to extinction probability relative to each term level were calculated by adjusting the original dataset so that all species were given the same value for that level (each level value in turn), keeping all other terms in the model as in the original dataset. Error bars represent the 10,000 iteration bootstrapped upper 95% confidence limits. aq = aquatic, arb = arboreal/phytotelms, ter = terrestrial, aq-ter = aquatic & terrestrial, ovi = oviparious, ovoviv = ovoviviparous, dir dev = direct development. See text and Supplementary Table S3 for a description of variables.

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References

    1. Pounds JA, Bustamante MR, Coloma LA, Consuegra JA, Fogden MPL, et al. Widespread amphibian extinctions from epidemic disease driven by global warming. Nature. 2006;439:161–167. - PubMed
    1. Stuart SN, Chanson JS, Cox NA, Young BE, Rodrigues ASL, et al. Status and trends of amphibian declines and extinctions worldwide. Science. 2004;306:1783–1786. - PubMed
    1. Beebee TJC, Griffiths RA. The amphibian decline crisis: a watershed for conservation biology? Biol Conserv. 2005;125:271–285.
    1. Kiesecker JM, Blaustein AR, Belden LK. Complex causes of amphibian population declines. Nature. 2001;410:681–684. - PubMed
    1. Lips KR, Burrowes PA, Mendelson JR, Parra-Olea G. Amphibian declines in Latin America: widespread population declines, extinctions, and impacts. Biotropica. 2005;37:163–165.

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