Methods of Studying Butterflies

Abstract

In the assessment of butterfly distribution, it is necessary to account for imperfect species detection at the sites of studies. This can be achieved through conducting repeated presence or absence surveys within a single season, and analyzing data with statistical models that estimate detection probability and site occupancy by a species. Transect counts, predominantly used for assessing butterfly abundance in monitoring programs, are cost-effective and easy to implement, but less reliable than mark–release– recapture sampling frequently applied for the same purpose in research studies. Deficiencies of transect counts stem from the fact that they do not account for individual detection probability and temporal fragmentation of butterfly populations, i.e., the situation in which just a small fraction of individuals belonging to a single generation is present on any day of a season. Consequently, transect counts can only yield relative abundance indices, which presumably correlate well with daily butterfly numbers, but not necessarily with their seasonal sizes of the butterfly‟s population