Modelling the effect of intersections in linear habitat on spatial distribution and local population density

Abstract

Many species in human-dominated landscapes find their habitat in linear elements, such as road verges, hedgerows and ditches. Local concentrations of species have been observed in the intersections of linear elements, but their spatial distribution and local population density in this linear habitat are not well captured by existing theory. Using a simple, spatially explicit individual-based GIS-model simulating hedgerow bird species with different movement abilities, local high population density of our model species in intersections and their reduced density or absence in linear habitat could be explained by limited movement. We hypothesise that, for species with low movement ability, intersections of linearly shaped habitat could contain several local populations. We argue that these predictions are valid for organisms occurring in linear habitat with limited movement relative to the dimensions of their habitat, and whose movement is directed by their habitat. Our findings support the importance of intersections for biodiversity in human-dominated landscapes, as they may serve as refuges from which individuals can (re-)colonise unoccupied habitat.