Distributional patterns of jumping spiders (Araneae: Salticidae) in Australia


*B. J. Richardson, CSIRO Entomology, GPO Box 1700, ACT 2601, Canberra, Australia.
E-mail: barry.richardson@csiro.au


Aim  To analyse observed and predicted distributional patterns of selected salticid genera in Australia and to examine these distributions in the light of the origins and attributes of the fauna. To detect and compare the locations of regional hotspots when measured using different scales.

Location  Australia.

Methods  A total of 4104 locality records for specimens of 51 genera were stored in BioLink. Maps of observed and predicted (using bioclim) distributions were prepared for each genus. The predicted distributions were combined to provide estimates of the number of genera likely to be found at each locality in the raster and for each of a set of landscape regions across Australia. The predictions were tested by comparing them with independent data sets.

Results  The Australian salticid fauna consists of radiations based on Oriental, Papuan and possibly Gondwanan forms, plus pantropical and peridomestic species. The predicted distributions of genera fall into a limited number of categories and these reflect the traditional biogeographical regions of Australia. Maximum regional diversity is predicted for central eastern Queensland, though diversity at single locations is highest further south in the New South Wales/Queensland border region. The locations of hotspots are therefore scale dependent. Patterns of distribution are not simply related to particular lifestyles. Fewer genera were predicted from inland Australia; however, recent work has shown that there are a large number of undescribed genera in the drier parts of Australia. The prediction maps allowed lists of genera potentially present in unstudied areas to be developed.

Main conclusions  (1) The current distribution of genera is predicted by their bioclimatic profiles rather than by their origins or ecology. Some Oriental genera, however, have not reached south-western Western Australia, though bioclimatic conditions there are predicted to be suitable for them; (2) the highest diversity of genera is predicted to be in south-eastern Queensland; (3) the results highlight the shortcomings of past fieldwork in Australia, which has concentrated on the areas with higher rainfall; (4) it seems likely that inland Australia will support a large, highly endemic, fauna adapted to the region, and ultimately perhaps 40 or more genera could be found in each region; (5) the results show the possibility of using the maps of predicted distribution of genera not only for biogeographical analyses but also for conservation management and survey purposes.