Kuala Belalong, Brunei: a hotspot of Old World butterfly diversity.

Abstract

Butterflies were sampled extensively over a two year period in an area, approximately 1 km² in extent, of lowland mixed dipterocarp forest in Brunei, N.W. Borneo. A total of 342 species were recorded, and from the species accumulation curve the total number of species present in the area was estimated to be 464, or nearly half the total Bornean fauna. With respect to the Bornean total, Papilionidae and Pieridae were proportionally better represented than Nymphalidae, Hesperiidae or Lycaenidae, a result which is probably partly a function of sampling bias, but may also reflect a more general distribution of species of the first two families. Of 151 commoner species, 80 were restricted in their distribution within the area, in some cases to very small areas of a few hundred m2. When species recorded in this study and published records for the surrounding Ulu Temburong region (up to 2000m asl) were combined and compared with species lists for Gunung Mulu National Park, Sarawak (50 km distant), and Mount Kinabalu National Park, Sabah (200 km distant), slightly greater similarities were found between Temburong and Mulu, than Temburong and Kinabalu. Combining the species lists for the three areas leads to a total of 666 recorded species, or two thirds of the Bornean total, suggesting that ultimately almost all Bornean species could be found in these three areas.