Fungal colonization of resources in soil — An island biogeographical approach

Abstract

The colonization of various sizes of Cellophane squares by soil hyphomycetes was followed over a 12-day period. After 2 days an apparent non-interactive equilibrium number of species colonized each square and species turnover occurred without competitive exclusion and other forms of species interference playing a role in species extinction. Species extinctions were more likely due to density-independent factors operating on the small number of colonists. However, each Cellophane square had a turnover of some species with a ‘unit community’ or guild of others remaining together, and the probability of extinction appeared to be species specific. At equilibrium each Cellophane square size supported a different mean number of fungi, that being 2, 3, 5, 7 and 11 on square sizes of 4, 16, 64, 256 and 1024 mm 2 respectively. The data provided empirical justification for the conventional species-area model associated with the equilibrium theory of island biogeography. This is a power function model, S = cA z , where S and A are the species count and area respectively, and c and z are fitted constants of 0.908 and 0.363 respectively.