DISTRIBUTIONAL PATTERNS OF HERPETOFAUNA IN MONSOON RAIN-FORESTS OF THE NORTHERN-TERRITORY, AUSTRALIA

The herpetofauna of 50 monsoon rainforest patches in the Top End of th e Northern Territory was surveyed during the dry season of 1990. This fauna contains few obligate monsoon rainforest species, many species w hich favour this habitat as part of a broad habitat range and a large number of species (indeed most of the regional species pool) that occa sionally occur within monsoon rainforests. The taxonomic composition o f species favouring monsoon rainforests is a non-random selection from the regional pool, with relatively few species in the families Agamid ae and Scincidae occurring commonly in monsoon rainforests. Environmen tal variation among the rainforest patches sampled was portrayed by or dination, with the first axis corresponding to an environmental gradie nt from coastal sites to inland rocky rainforests and the second a gra dient from relatively dry thickets to tail dense rainforests close to water. The distributions of herpetofauna species were depicted on this ordination space. Most frog species occurred in relatively wet rainfo rests and most gecko species were relatively restricted to drier rainf orests. A substantial component of the herpetofauna was associated wit h rainforests on rocky substrate.fluctuations in extent and distributi on of this habitat are probably at least as important.