Butterflies as potential bioindicators of primary rainforest and oil palm plantation habitats on New Britain, Papua New Guinea.

Abstract

Our research team worked with Nakanai land-holders in Papua New Guinea to perform the first survey of butterflies in the Lake Hargy caldera of West New Britain Province. Methods included modified Pollard transects quantifying sampling effort based on aerial netting and visual observations, as well as traps baited with fermenting fruit. Results were compared with surveys on the adjacent Hargy Oil Palm plantation. Our sampling yielded 312 specimens representing 73 species; of these, 50 were limited to primary rainforest, 12 to oil palm plantation and 11 species occurred at both sites. Four species are newly recorded for New Britain, including one potentially invasive species on Citrus. Singleton specimens made up the largest abundance class in the data set, representing 34% of records in primary rainforest. Sixty-two percent of the butterfly taxa recorded are regionally endemic to the Bismarck island chain or to New Britain in particular. Calculated levels of similarity between sites ranged from 0.151 to 0.262, suggesting the oil palm and rainforest habitats supported highly distinct species assemblages. Although rapid assessment data such as these are necessarily limited in scope, they can still aid in documenting the impact on biodiversity from conversion of primary tropical rainforest to oil palm monoculture.