Population dynamics and habitat connectivity affecting spatial spread of populations - a simulation study

Söndgerath, Dagmar & Boris Schröder (2002): Landscape Ecology 17(1): 57-70

Abstract: In this paper we show how the spatial configuration of habitat quality affects the spatial spread of a population in a heterogeneous environment. Our main result is that for species with limited dispersal ability and a landscape with isolated habitats, stepping stone patches of habitat greatly increase the ability of species to disperse. Our results show that increasing reproductive rate first enables and then accelerates spatial spread, whereas increasing the connectivity has a remarkable effect only in case of low reproductive rates. The importance of landscape structure varied according to the demographic characteristics of the population. To show this we present a spatially explicit habitat model taking into account population dynamics and habitat connectivity. The population dynamics are based on a matrix projection model and are calculated on each cell of a regular lattice. The parameters of the Leslie matrix depend on habitat suitability as well as density. Dispersal between adjacent cells takes place either unrestricted or with higher probability in the direction of a higher habitat quality (restricted dispersal). Connectivity is maintained by corridors and stepping stones of optimal habitat quality in our fragmented model landscape containing a mosaic of different habitat suitabilities. The cellular automaton model serves as a basis for investigating different combinations of parameter values and spatial arrangements of cells with high and low quality.