The simpler the better: When decreasing landscape complexity increases community stability

Herbivores and their predators are affected by changes in land-use and habitat fragmentation. Past studies of tri-trophic herbivore communities have found that increasing land-use intensity leads to declines in community stability. The majority of these studies analysed community stability in highly fragmented ecosystems characterised by intensive agriculture. In this study we considered how landscape configuration and composition affected habitat networks and parasitoid food webs under moderate but increasing land use. We used gall wasp communities as models to test the effects of landscape change on multi-species hierarchical communities of plants and animals. We investigated characteristics of networks formed by rose bushes and quantitative webs of rose gall parasitoids along a gradient of land-use intensity. We found that link density and compartmentalisation of rose bush networks, and local extinction within parasitoid webs increased with increasing landscape homogenization. Because these network and web characteristics are linked with resilience, our results suggest that stability of these communities can increase as landscapes become less complex. This is an intriguing aspect of landscape homogenisation effects on biological communities that contrasts with most expectations and the majority of the relevant literature, where decreasing community stability is usually associated with landscape homogenization.