SAMPLING CARABID ASSEMBLAGES WITH PITFALL TRAPS - THE MADNESS AND THEMETHOD

We describe a litter-washing technique for collecting quantitative sam ples of ground-beetles (Carabidae), and compare the results with those from litter extraction by Tullgren funnels and pitfall trapping. We a lso compare performance of four types of pitfall traps across five hab itats. Carabid species composition from litter washing and funnel extr action was similar but washing revealed higher densities. Large-bodied species predominated in pitfall samples and small-bodied species pred ominated in litter samples. Uncovered, round pitfall traps yielded gen erally higher catches than rectangular or covered, round traps but the pattern was not consistent over all species or the five habitats. Eco logical studies of carabid populations and assemblages using pitfall t raps may be improved if they are both designed and interpreted in ligh t of the biology of the group and with regard to the deficiencies of p itfall trapping as discussed here and elsewhere.