Factors explaining shrub species distribution in hedgerows of a mountain landscape

In order to assess the relative role of local versus landscape variables on shrub species composition and the species richness of hedgerows, a multi-scale approach was used. Along with landscape heterogeneity indices, graph theory derived indices were used to explore physical connectivity in hedgerow networks. Variation partitioning was conducted by partial Canonical Correspondence Analysis (CCA) for shrub species composition, and multiple regression for shrub species richness. Shrub species composition and shrub species richness are determined by several interrelated factors: (1) the influence of adjacent land use was weak, while other local variables, e.g. hedgerow type, management and structure variables, were more important; (2) broad spatial scales explained more variation in shrub species distribution in hedgerows than fine spatial scales, probably in relation to their dispersal syndromes; (3) the main factors explaining variation in shrub species composition were landscape patterns variables, and (4) shrub species richness, however, was principally explained by local variables. Therefore, local and landscape variables have balancing effects, and both should be considered when explaining species distribution in hedgerow networks. (c) 2006 Elsevier B.V. All rights reserved.