The Site includes about 690 hectares of water and 22 small islands, with alluvial meadows and bush zones on the shores, surrounded by a narrow forest zone and agricultural land. It is the most valuable of the North Karelian lakes for birds and among the ten most important wetlands in Finland, due to the high diversity of breeding and migrating wetland birds. The Site supports notable species during their migrations, such as black-tailed godwit (Limosa limosa), rustic bunting (Emberiza rustica) and pallid harrier (Circus macrourus). Discharges from sewage plants, mining industries and agricultural land have polluted the Lake’s waters and as a consequence some plant species have disappeared during the last ten years. The waters of River Lahdenjoki contain notably high loads of nutrients. A project has been implemented under the the European Union’s LIFE Programme, which included the restoration of meadows, removing of aquatic plants and intensifying the removal of predatory mammals such as raccoon dog (Nyctereutes procyonoides) and American mink (Mustela vison). Two birdwatching towers have been constructed.