Denis Couvet, Anne Mimet, Jens-Christian Svenning, Colin Fontaine, Vincent Pellissier
Humans are changing the biosphere by exerting pressure on land via different land uses with variable intensities. Quantifying the relative importance of the land-use composition and intensity for communities may provide valuable insights for understanding community dynamics in human-dominated landscapes. Here, we evaluate the relative importance of the land-use composition versus land-use intensity on the bird community structure in the highly human-dominated region surrounding Paris, France. The land-use composition was calculated from a land cover map, whereas the land-use intensity (reverse intensity) was represented by the primary productivity remaining after human appropriation (NPPremaining), which was estimated using remote sensing imagery. We used variance partitioning to evaluate the relative importance of the land-use composition versus intensity for explaining bird community species richness, total abundance, trophic levels, and habitat specialization in urban, farmland, and woodland habitats. The land-use composition and intensity affected specialization and richness more than trophic levels and abundance. The importance of the land-use intensity was slightly higher than that of the composition for richness, specialization, and trophic levels in farmland and urban areas, while the land-use composition was a stronger predictor of abundance. The intensity contributed more to the community indices in anthropogenic habitats (farmland and urban areas) than to those in woodlands. Richness, trophic levels, and specialization in woodlands tended to increase with the NPPremaining value. The heterogeneity of land uses and intensity levels in the landscape consistently promoted species richness but reduced habitat specialization and trophic levels. This study demonstrates the complementarity of NPPremaining to the land-use composition for understanding community structure in anthropogenic landscapes. Our results show, for the first time, that the productivity remaining after human appropriation is a determinant driver of animal community patterns, independent of the type of land use.
We use the productivity remaining after human appropriation (NPPt, Proceedings of the National Academy of Sciences of the United States of America, 2007, 104, 12942) as a measure of land-use intensity and compare its importance with land-use composition in explaining structure of bird communities. The importance of the land-use intensity was slightly higher than that of the composition for richness, specialization, and trophic levels in farmland and urban areas, while the land-use composition was a stronger predictor of abundance.