A GIS based spatially explicit model of dispersal agent behavior

Spatial simulation models of seed dispersal have been constructed at the landscape level under the assumption of ubiquitous or uniform dispersibility. The anisotropic nature of vegetation distribution caused by different dispersal agents such as wind, gravity, water and animals were ignored. We propose a prototype of a GIS-based spatially explicit model of dispersal agent behavior (SEMODAR) to simulate the seed dispersal process by considering the unique behavioral characteristics of each seed dispersal agent. As a result, the influence of dispersal agent behavior on the species coexistence in competitive communities with and without habitat destruction could be explored. The model consists of four module components: dispersal rules, species competition, species colonization, and habitat destruction. An experimental simulation was conducted using three hypothetical species with differing competitive and migration abilities in both intact and disturbed conditions for 250 years. The findings of this study support the theoretical expectation that inferior competitors can coexist with superior competitors given that the inferior competitors have efficient colonization ability. The simulation also reveals the important role of agent behavior in the seed dispersal process and the biased impact of environment fragmentation on superior competitors that are not superior dispersers. (c) 2007 Elsevier B.V. All rights reserved.