WILDLIFE OF LANCEWOOD (ACACIA-SHIRLEYI) THICKETS AND WOODLANDS IN NORTHERN AUSTRALIA .1. VARIATION IN VERTEBRATE SPECIES COMPOSITION ACROSSTHE ENVIRONMENTAL RANGE OCCUPIED BY LANCEWOOD VEGETATION IN THE NORTHERN-TERRITORY

Vegetation dominated by lancewood (Acacia shirleyi) occurs extensively across me Northern Territory and Queensland. We sampled the vertebrat e species composition at 61 patches of lancewood in the Northern Terri tory (including 22 patches where quadrats were intensively sampled), a nd relate the distribution of species to a wide range of environmental characteristics, spatial variables, disturbance and season. Of 165 sp ecies recorded from lancewood patches, eight species were recorded fro m more than half of the sampled patches: Pachycephala rufiventris, Pom atostomus temporalis, Rhipidura leucophrys, Cracticus nigrogularis, Me lanodryas cucullata, Geopelia cuneata, G. placida and Macropus robustu s. Environmental variation within sampled lancewood sites was describe d by classification of 51 quadrats into 7 classes, and the 61 patches into 5 classes. Vertebrate species showed limited association with thi s classification, with a few species associated with the occasional co -dominant tall shrub Macropteranthes kekwickii, other species associat ed with variation in rockiness or soil texture, and other species asso ciated with variation in the occurrence of Eucalyptus species within l ancewood vegetation. An ordination of all quadrats by their vertebrate species composition suggested a loose patterning associated mainly wi th latitude and, less strongly, soil texture and co-occurring tree/shr ub species (notably Eucalyptus and Macropteranthes). Suggesting a depa uperate and poorly defined vertebrate community in lancewood, quadrats in small isolated lancewood patches had more species than those in la rge patches, and this pattern was shown for many individual species. L ancewood patches showed some impact of grazing and logging, but this w as generally minor and could not be demonstrated to have any consisten t relationship with the abundance of individual species. In contrast, impacts of fire were generally more severe, and were negatively associ ated with the abundance of relatively many species. Lancewood vegetati on is not represented in any conservation reserve in the Northern Terr itory.