Small-mammal species richness and abundance along a tropical altitudinal gradient: an Australian example

This study examined patterns in the species richness and abundance of small non-volant mammals along a tropical altitudinal gradient in north-eastern Australia. We investigated whether a mid-altitudinal peak in diversity was apparent. and if it. occurred, whether it. was determined by particular environmental conditions. e sampled it small-mammal assemblage at 17 sites distributed along an altitude-environmental gradient I, from savanna (350 m) to rain-forest vegetation (1000 m). Over four separate occasions (5100 trap-nights) we recorded 17 species of mammal with 416 Captures. A positive non-linear relationship between altitude and mammal species richness and abundance was observed. peaking at. the 800-900 in range. Many species were distributed across a range Of attitudes, while others were strongly associated with particular habitat conditions. There was it distinct, reduction in abundance and Species richness at. low attitudes associated with the less complex vegetation. lower productivity and possible anthropogenic effects. Key findings were: that, small-mammal richness peaked towards the summit, of the gradient and not at one-half the maximum altitude predicted by the mid-domain effect: contrasting conditions and greatest vegetation juxtaposition had the greatest influence on the patterns recorded: and that local idiosyncratic influences Such as habitat factors, kind management and historical biogeography are significant.