Abundance-range size relationships in the herbaceous flora of central England

Abstract

1. Using data from a survey of over 10 000 1-m2 quadrats in a 3000-kin2 area, we examined the relationship between abundance and range for the vascular plant flora of central England. 2. At the level of the whole landscape, abundance was not related to local, regional or national range. Local, regional and national range were closely related to each other. 3. At the level of the whole landscape, range was significantly and positively related to both niche breadth (expressed as the range of habitats exploited) and to habitat availability, although niche breadth appeared to be more important. Abundance was not related to niche breadth or habitat availability. Since specialist species are mainly confined to uncommon habitats (especially wetlands), we conclude that the relationship between range and niche breadth is not an artefact of widespread species passively sampling more habitats. 4. At the level of individual habitat types, significant positive relationships between range and abundance were common. These relationships remained after controlling for the effects of phylogeny. For predominantly annual weed communities, the relationship was linear, but for perennial communities it was markedly 'upper triangular', i.e. all combinations of range and abundance were found except wide range/low abundance. The evidence suggests that this difference can be attributed to the greater mobility of annual weeds.