Estimates of forest floor litter frog communities: A comparison of two methods

Estimates of forest leaf litter frog density, mass, richness and diversity given by the widely used 8 m x 8 m large plot method (LPM) were compared wi th estimates obtained by a newly proposed method (small 2 m x 1 m plots wit h leaf removal; SPLR). The study site was an undisturbed area of the Atlant ic Rainforest of Ilha Grande, an island located in the south of Rio de Jane iro State, Brazil. Twenty-four LPM (totalling 1536 m(2) of forest floor) an d 90 SPLR (totalling 180 m(2) of forest floor) were performed. The estimate s obtained by the two methods differed markedly, indicating that even using a much smaller sampling area (11.7% of that of LPM), SPLR gave frog densit y estimates six times higher, and frog mass estimates approximately 2.5 tim es higher than estimates provided by LPM. The species richness and diversit y obtained by the two methods were similar, despite the fact that the total area sampled with SPLR was much smaller. These data suggest that LPM may u nderestimate the abundance and biomass of leaf litter frogs in a given area .