Biodiversity assessment: a case study in predicting richness from the potential distributions of plant species in the forests of south-western Australia

Distributions were predicted for 1430 native plant species as part of a bio diversity assessment in the forests of south-west Western Australia. From t hese predicted distributions, an index of plant species richness was genera ted for the forest area. The most common predictors for distribution were f ound to be climatic surfaces incorporating some aspect of seasonality in te mperature and precipitation. Although coarse, the index confirmed existing knowledge of areas of high biodiversity within the study area and introduce d a new area, the Blackwood Plateau, for consideration as a conservation re serve with high species richness. An additional survey was conducted to sam ple actual species richness in 11 test sites. When actual richness was regr essed against predicted richness, a significant correlation was obtained if both annuals and geophytes were excluded from the analysis. With refinemen t of the model and further data collection targeted at areas of low effort, the species richness index is proposed as a useful tool for conservation p lanning.