A model for species-area relationships in plant communities

A model is proposed for the fitting of species-area curves to data from the Stellenbosch region, South Africa. Basic assumptions of the model are finiteness of the number of species in a finite area, and random distribution of plant species over the region. The model involves a distribution of densities of different species, and the parameters of this distri- bution are useful for describing and classifying communities. The data of the Stellenbosch region suggest that the assump- tions of the model break down in areas greater than 500 m2.