Habitat configuration, species traits and plant distributions

Abstract

1 In a metapopulation context, the distribution of a species in a patchy landscape is interpreted as the equilibrium outcome of extinction and colonization processes. Populations are thus more likely to occur in larger, better connected habitat fragments. 2 To test whether metapopulation models explain distribution patterns of plant species with different life histories we investigated the incidence of herbaceous species in deciduous forests in four provinces of south Sweden. 3 These data were correlated with habitat quality (soil pH, nitrogen mineralization and organic matter) and habitat configuration (patch area and distance to the nearest deciduous forest patch). We also examined whether habitat configuration affected the distribution of species with different life history attributes. 4 All ground layer plant species at 81 sites were recorded, and distribution patterns of 57 species were tested against seed mass, seed number, presence of a seed bank, plant height, life span, mode of pollination, dispersal mode and habitat preference. 5 Habitat quality, especially pH, was more important for the incidence of species than habitat configuration with patch area and isolation significantly affecting only 11 and four species, respectively. Species favoured by larger area were also disadvantaged by greater isolation. 6 The importance of habitat configuration to a species varied with life history. Species that were more negatively affected by patch isolation tended to be habitat specialists and clonal perennials and to produce fewer seeds. Animal-dispersed species were more negatively affected by small stand size. 7 Habitat configuration may be less important for vascular plant distributions than habitat quality or the effects of land use history.