An area-based model of species richness dynamics of forest islands

Landscape fragmentation results in forest islands surrounded by a matrix of agricultural species, at least above the minimum size necessary for the interior species. The species richness dynamics of these forest islands can be predicted by using mathematical modelling. Our area-based model describes the temporal dynamics of species richness of forest islands and depicts relationships between species richness and the edge, interior, and total area of forest islands. The mathematical model consists of a group of differential equations, and we also present results of a STELLA simulation model on woody species of deciduous forest islands. Simulations show that changes in species richness occur only when the area of forest islands is smaller than some threshold level which is different for the edge and interior species groups, that edge and interior species respond differently to the changes in island area, and that time delays embedded in community level responses may be important to understanding species richness dynamics of forest islands. The STELLA model is capable of simulating the dynamics of edge, interior, and total species richness with a variety of additional scenarios involving the change in area of forest islands.