Patch density, movement pattern, and realised dispersal distances in a patch-matrix landscape—a simulation study

Abstract

In metapopulation models it is common practice to use species-specific dispersal distances to predict the exchange of individuals between habitat patches. The influence of patch distribution on the reachability of a habitat patch is usually ignored. In a patch-matrix simulation, we investigated the effect of patch number, movement pattern and dispersal mortality on realised animal dispersal distances. In our spatially-explicit, individual-based simulations we demonstrate that: (1) with increasing number of patches the number of immigrants into patches further away from the release point decreases in all scenarios (“shadow effect”), (2) this effect is strongest for a random movement, (3) for rather uncorrelated walks a proper adjustment of mean dispersal distance in the negative exponential model can account for the effect of patch density on realised dispersal distances, (4) with a more directed walk this is not possible as the distribution of moving animals in the matrix becomes highly heterogeneous. This is due to the narrow but far reaching shadow patches exert on other patches further away from the release point.