Monitoring the Green and Golden Bell Frog: current problems and an alternative approach

Abstract

The Green and Golden Bell Frog Litoria aurea is the subject of a number of population monitoring studies to assess its long-term status. However, we question the value of standard monitoring strategies for this species. The numbers of frogs detected at a single pond can be highly variable over time, creating significant variance in population estimates and so serious difficulties in statistically detecting population changes. The species is also believed to exhibit a metapopulation structure with natural levels of site extinctions balanced by site colonisations. Traditional monitoring would view site declines as serious impacts on the population, but they are insignificant if balanced by the colonisations. We believe that population estimates using site occupancy modelling may be a better method of monitoring Green and Golden Bell Frog populations. We explore this option, comparing it to traditional approaches, and consider that monitoring site occupancy should be time-effective and statistically more sen...