Biological inventory for conservation evaluation .1. Design of a field survey for diurnal, terrestrial birds in southern Australia

A systematic, stratified, regional biological survey was designed and implemented to sample the variation in bird and vegetation assemblages in an area of some 758 129 hectares of open Eucalyptus forest in south east Australia. The survey design was based on spatial estimates of abiotic attributes (terrain, climate and nutrient-supply potential of the substrate) and vegetation cover for a 9 second grid of longitude and latitude (250 x 250 metres) for the study region. A climate stratification consisting of a matrix of five classes of minimum temperature of the coldest month and four classes of mean precipitation of the driest quarter was constructed representing an environmental gradsect which inherently incorporated the steepest altitudinal gradients in the study region. Using digitally-stored LANDSAT vegetation cover data, the climate stratification was constrained to climate domains associated with the extant forest cover. Fourteen climate domains identified across the forested region were then stratified on two broad categories of the nutrient-supply potential of the substrate. This resulted in the definition of 24 climate/nutrient domains across the study region, of which 23 were sampled by the survey.