RAIN-FOREST FRAGMENTATION AND THE STRUCTURE OF SMALL MAMMAL COMMUNITIES IN TROPICAL QUEENSLAND

There is a dire need to assess the impacts of habitat fragmentation on tropical forest biotas. In 1986-1987 three live-trapping methods were used to census small mammals at 52 sites in fragmented and unfragmented rainforest in NE Queensland, Australia. Forest structural, floristic, edaphic and landscape data from each site were used to assess patterns of microhabitat use in common species. Trapping censuses yielded 5,784 captures of 15 species of rodents or marsupials. Species encountered in modified habitats surrounding fragments usually remained stable or increased in fragments (Melomys cervinipes, Rattus leucopus, R. fuscipes, Uromys caudimaculatus, Antechinus flavipes, Hydromys chrysogaster), whereas those that avoided these habitats declined or disappeared (A. stuartii, A. godmani, Hypsiprimnodon moschatus). Fragments were more heavily disturbed within 200-500 m of forest edges, and mammals that favored disturbed forest or edges (Melomys, R. leucopus, A. flavipes) increased in many fragments. Assemblages of abundant native rodents appeared more intensively structured in fragments than in unfragmented forest, with strong competitive interactions occurring between ecologically similar species in fragments.