Diversity and community structure of geometrid moths of disturbed habitat in a montane area in the Ecuadorian Andes

Abstract

Abstract: The diversity and faunal composition of geometrid moths (Lepidoptera: Geometridae) was investigated at two sites within an anthropogenically disturbed habitat mosaic at 1950 m and 2005 m a.s.l., in the vicinity of intact Andean montane rainforest in southern Ecuador. A total of 629 specimens belonging to 197 species were collected. The results were compared with those from ten sites of undisturbed forest habitats within an elevational range of 1800–2212 m. The local diversity of the moths at disturbed sites was surprisingly high (Fisher’s alpha: 86.1 and 86.8; rarefied species number at the level of 250 specimens: 117 and 113; extrapolated species number, estimator Chao 1: 220 and 303). Forest successions and remnants probably serve as habitats for many species, but diversity is possibly overestimated due to the presence of ‘tourist species’ from adjacent forests. Disturbed habitats were characterized by a low diversity in the genera Eois, Bonatea and Herbita, probably due to the absence of their potential host plants (e.g. Piper species). Only three moth species represented by more than three individuals were found exclusively in disturbed habitats (Eupithecia densicauda, Pero obtusaria, ‘Sabulodes’ muscistrigata). Some 25 species profited from disturbance, among these were six species of the genus Eupithecia. The proportion of species present with only one specimen was high (56 and 62%), and species dominance was low (Berger- Parker index: 7.9 and 5.8%). In two-dimensional scaling based on the CNESS index of dissimilarity, disturbed sites are separated from the forest sites. The conservation of secondary forest remnants and natural forest appears to be essential for the survival of the very species-rich Andean geometrid moth communities.