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

Abstract

This paper examined vascular-plant and cryptogam speciesdiversity on different spatial scales in semi-natural grasslands alonganelevational gradient ranging from 530 m a.s.l. (southernboreal region) to 1230 m a.s.l. (low alpine region)in Vang, southern Norway. Species diversity of vascular-plants on asmallscale (0.25 m2) peaked atmid-elevations. Diversity at low elevations was not higher than that ofhigh elevations, but diversity on a large scale decreased continuously withelevation. Cryptogam diversity increased with elevation on all scales. Highsmall-scale vascular-plant diversity at high elevations waspositively related to species abundance which increased with elevation, andsuggests an area effect along the gradient. Most species atmid-elevational levels (750 and 915 m a.s.l.) didalso occur at other levels. Lowland vascular-plant species constituted50% of the species in the low alpine region. Collectively, these patternsreflect the importance of regional dynamics along the gradient. Environmentalvariables such as topography, biomass, soil variables were less important forexplaining variation in vascular plant diversity, and it is suggested thatland-use processes such as grazing, mowing, fuel-wood cuttinghavelevelled out the effects of other variables along the gradient.