Heterogeneous landscapes promote population stability.

Habitat heterogeneity is often suggested as being important for the stability of populations, and promoted as a means to aid the conservation of species, but the evidence for such an assumption is poor. Here we show that heterogeneous landscapes that contain a variety of suitable habitat types are associated with more stable population dynamics for 35 British butterfly species from 166 sites. In addition, topographic heterogeneity may also promote stability. Our results were robust to different measures of population variability, differences in mean abundance among sites, and to the spatial scale (radius 1-5 km around the centres of sites) at which landscapes were analysed. Responses to landscape heterogeneity differed among species; for more mobile 'wider-countryside' species, habitat heterogeneity at larger landscape scales had the strongest effect on population dynamics. We suggest that heterogeneous landscapes offer a greater range of resources and microclimates, which can buffer populations against climatic variation and generate more stable population dynamics.