Interactions between forest harvesting, landscape heterogeneity, and species persistence

The combined effect of landscape heterogeneity, natural disturbances, and the scale of forest harvesting was simulated for two competing annual plant species. One species was a generalist, able to utilize all habitat types, whereas the second species was a specialist restricted to a single habitat. Individuals of both species completed their life cycles in a single time step, competed with neighbors for germination sites via a seed lottery, and were distributed on a series of heterogeneous grided landscapes, which differed in the scale of habitat fragmentation. Simulated forest harvesting altered habitat types by preventing specialists from germinating. Survival of specialists was highest when habitat was more aggregated at fine scales. Harvesting had a negative effect on survival and abundance of the specialist when the scale of harvesting interacted with the landscape patterns to increase habitat fragmentation. Natural disturbance also interacted with harvesting and landscape pattern to dramatically increase the risk of loss of specialists. These results provide a practical basis for considering the complex interactions affecting species survival and for developing positive recommendations for balancing management objectives with the need to preserve biodiversity.