Patterns of diversity and structure of mammalian assemblages in the Australian tropics.

Abstract

The assemblages of small mammals (excluding bats) found in 15 broad habitat types in the tropical and sub-tropical, non-arid parts of Australia (i.e. the Torresian zoogeographic sub-region) were examined. Data from a wide variety of published and unpublished sources were used to develop relative indices of mammal density (0-4) for a total of 332 sites distributed over 65 regions. General estimates of diet, activity pattern, microhabitats and body size of each species were used to examine the niche characteristics of the different assemblages. Classifications of 107 species into 11 guilds and the 332 sites into 13 community types were performed. Two groups of habitat types emerged: an extensive major series with high mammal diversity and a restricted minor series of lower plant diversity occurring where water accumulates in landscapes. Support is provided for productivity, structural diversity, area, usurpation by external taxa and particularly for floristic diversity hypotheses of species diversity.