Bottom-nets as a new method for quantitatively sampling tadpole populations (Amphibia, Anura)

Abstract

A new technique to reliably estimate true tadpole abundance in small ephemeral forest ponds based on a sample taken from a bottom net is presented. The bottom net is placed in the pond before it fills with water. At given intervals the bottom net is lifted through the water column and all tadpoles can be counted. Based on a series of calibrations, the technique showed significant correlations between estimated abundance of Osteocephalus taurinus Steindachner, 1862, Colostelhus marchesianus Melin, 1941, Phyllomedusa tomoptema Cope, 1868, and aeshnid larvae, and true abundances based on total counts.