Biological survey has been an integral component of conservation planning in Western Australia for >30 years, providing baseline data for reserve selection and the management of biodiversity at the genetic, species and community levels. Flora surveys are particularly important, given the diverse and poorly documented nature of the state’s vascular flora. Surveys have been conducted at the following four scales: regional, subregional, local and individual species. At all scales, flora surveys have provided detail on individual taxon distribution, have identified previously unknown or unrecognised taxa, have located presumed extinct taxa and have substantially contributed to information on the distribution of threatened flora. Regional-scale surveys normally involve multidisciplinary teams studying a broad selection of the biota. These combined plot-based data are used to develop a ‘classify-then-model’ approach to assessment of comprehensiveness, adequacy and representativeness of the regional conservation reserve system. These regional models describe the broad-scale patterning of common taxa but their utility in reflecting patterns in naturally rare or highly restricted taxa is uncertain. Results from recent surveys show poor correlations between floristic patterning and other components of the biota.