The loss of native terrestrial small mammals in large urban reserves in the Australian Capital Territory

Abstract

Urban development can alter species composition and diversity within an area through biotic homogenization, the introduction of exotic species, and localized extinctions of native species. In this study we examined the composition and diversity of small terrestrial mammals within nature reserves surrounded by urban landscapes and compared this with previous surveys of these reserves and nearby non-urban reserves with similar vegetative and geomorphological characteristics. A combination of live trapping and indirect detection techniques was employed in eight reserves in the Australian Capital Territory and surrounding New South Wales to determine current species composition. Compared with previous studies and the non-urban reserves, the urban reserves appear to have lost two-thirds of their native terrestrial small mammal species in the past 26 years. Exotic species were present in all urban reserves, but were only associated with areas characterized by human-induced disturbance in non-urban reserves. Possible causes of this disparity in native species diversity between urban and non-urban reserves are discussed.