Changes in the spruce forest communities along a heavy metal deposition gradient on Kola Peninsula

We investigated changes in the community structure of spruce (Picea obovata and P. fennica) forests in the Northern Taiga Region of Russia along a poi nt-source atmospheric deposition gradient of heavy metals on the Kola Penin sula. Study sites were selected in ecologically analogous forest stands at increasing distances from the nickel smelter in Monchegorsk. The heavy meta l load at each site was estimated by quantifying metal concentrations in th e snow cower. Concentrations of heavy metals in soil, litter and vegetation increased along the gradient of increasing atmospheric deposition. All mea sured indexes of forest vitality, including species richness and abundance, vertical distribution, and understory structure were adversely affected by pollution.