Shift in soil-plant nitrogen dynamics of an alpine-nival ecotone

Abstract

We investigated the nitrogen (N) dynamics of an alpine-nival ecotone on Mt. Schrankogel, Tyrol, Austria, in relation to temperature. Natural abundance of 15N was used as a tool to elucidate differences in N cycling along an altitudinal transect ranging from 2,906 to 3,079 m, corresponding to a gradient in mean annual temperature of 2.4°C. The amount of total soil N, of plant available N and soil C/N ratio decreased significantly with increasing altitude, whereas soil pH increased. Soil δ 15N decreased with increasing altitude from +2.2 to -2.1‰ and δ 15N of plant tissues (roots and leaves) decreased from -3.7 to -5.5‰. The large shift in soil δ 15N of 4.3‰ from the lowest to the highest site..