Abstract
Logging disturbances in boreal watersheds generally leads to short-term increases in soil nutrient availability followed by increased leaching to freshwaters. There is a lack of knowledge on both short- and long terms effects of enhanced inorganic nitrogen (N) export from catchments due to logging on boreal lake ecosystems in northern Sweden. As phytoplankton mainly is N-limited in this region, enhanced N leakage may cause eutrophication. The project therefore aims to study how increased inorganic N export from logged catchments affects productivity and biostructure of down stream lake ecosystems. Short-term effects will be evaluated by studying lakes before and after logging (in lake- and mesocosms studies). Long-term effects will be evaluated by studying lakes in catchments with harvested areas of different ages. It will be assessed how excess inorganic N from logging affect pelagic productivity and plankton structure, and the energy transfer efficiency from basal trophic levels up to zooplankton. The capacity of the lake ecosystems to retain excess inorganic N will also be evaluated. The results intend to be used for management and protection of surface waters, and to advance forest management guidelines for limiting nutrient export from logged catchments and minimize its affects on water quality and planktonic biostructure in boreal lakes.
Sweden