Forest degradation as a factor of the snow cover and hydrological regime transformation in the pollution zone of lake Imandra

Degradation of terrestrial plant communities at "Severonickel" plant area (the Kola Peninsula, the town of Monchegorsk), in particular the woody layer of forest communities, has led to disturbance of the water regime and soil erosion. Early snowmelt is a consequence of the structure transformation in snow cover of the complete tree layer degradation. The increase of snow depth and density parameters is high in areas with the disturbed tree layer and is caused by a mosaic distribution of snow cover. The speed and duration of winds as well as relief significantly affect the snow cover density. Intensive wind influences in conditions of the rough terrain intersection have led to redistribution of snow: snow moves from the tops of relief to depressions and causes a strong variability in the depth and density of snow cover, especially during the snowmelt period. The snow cover is a convenient environment for depositing various pollutants which fall into the soil in the period of melting snow. From open and the most polluted territories of the impact zone thawed waters enter watercourses and reservoirs earlier than from afforested catchment areas. Removal of soil particles by groundwater into the hydrological network of Lake Imandra is an essential element of water objects eutrophication and causes early ice cover from lakes and streams along with early snowmelt in the zone of intensive pollution. Thus, results of the "Severonikel" plant activities are expressed in change in the hydrochemical regime, the structure and diversity of phyto- and zoocenoses for the hydrological water pond network of Lake Imandra.