The ecological characteristics of declining frogs in Australia: Implications for global amphibian declines

Jean-Marc Hero, Stephen E. Williams, and William E. Magnusson

School of Environmental & Applied Sciences, Griffith University Gold Coast, PMB 50 Gold Coast MC, Queensland 4127 Australia

Email: M.Hero@mailbox.gu.edu.au

Declining frog species from relatively undisturbed sites at high altitudes throughout eastern Australia, share a combination of ecological characteristics that distinguish them from non-declining species. Species experiencing severe population decline have an aquatic life-history stage and small clutch size. Geographic range is a good surrogate predictor of conservation status, as species with small clutch sizes tend to have small geographic ranges. Similar results are also proposed for declining amphibians in North and South America. Using this model, extinction prone species can be predicted in other countries, and population surveys instigated to determine their current status. Implications for the determination of causal factors contributing to global amphibian declines are also presented. An aquatic larval stage suggests a causal agent associated with the aquatic environment at high altitudes. This agent may affect all species, but those with naturally low population "resilience" (low fecundity and small geographic range) are more susceptible.