Soil nutrient’s spatial variability in forest–tundra ecotones on the Kola Peninsula, Russia

This article addresses spatial variability in soil nutrients in altitudinal and latitudinal forest–tundra ecotones in the Kola Peninsula, Russia. Higher total carbon, nitrogen, and bio-available nutrients were found in the organic horizons of latitudinal ecotone against the background of lower nutrients in soil-forming rock. This is supposedly related to higher contribution of nutrient-rich plants in latitudinal ecotone and intense downward within-profile matter migration in the altitudinal ecotone. Elevated bio-available soil nutrients in spruce forests compared with birch forests and tundra sites, and in birch forests compared with tundra against the background of different trends in the soil-forming rock were attributed to the effects of predominant plants. The effects of predominant plants on soil nutrients were distinctly pronounced at the level of site patches. Soil-forming rock effects on soil nutrients were clear at the level of zones/belts and the whole ecotones. Strong negative correlations between the soil nutrients and altitudes were explained by replacement of vascular plants by low-ash lichens at higher elevations.