Plant diversity patterns in semi-natural grasslands along an elevational gradient in southern Norway

This paper examined vascular-plant and cryptogam species diversity on different spatial scales in semi-natural grasslands along an elevational gradient ranging from 530 m a.s.l. (southern boreal region) to 1230 m a.s.l. (low alpine region) in Vang, southern Norway. Species diversity of vascular-plants on a small scale (0.25 m(2)) peaked at mid-elevations. Diversity at low elevations was not higher than that of high elevations, but diversity on a large scale decreased continuously with elevation. Cryptogam diversity increased with elevation on all scales. High small-scale vascular-plant diversity at high elevations was positively related to species abundance which increased with elevation, and suggests an area effect along the gradient. Most species at mid-elevational levels (750 and 915 m a.s.l.) did also occur at other levels. Lowland vascular-plant species constituted 50% of the species in the low alpine region. Collectively, these patterns reflect the importance of regional dynamics along the gradient. Environmental variables such as topography, biomass, soil variables were less important for explaining variation in vascular plant diversity, and it is suggested that land-use processes such as grazing, mowing, fuel-wood cutting have levelled out the effects of other variables along the gradient.