The purpose of this paper is to compare trophic characteristics of the ecosystems of small and shallow lakes with a different character of land-cover in their catchments (as exemplified by several previously unstudied lakes of the Leningrad Region, North-Western Russia, that belong to a single lake-river system).
The key limnetic parameters of four lakes are analysed. Two of the lakes are located on the territory of allotment gardens, the other two are in the forest-covered areas. A preliminary assessment was made for the production-to-destruction ratio in the ecosystems of the lakes of the study region and their vulnerability factors.
For the lakes with a largely unexploited catchment, humus of terrigenous origin can act as a “hidden” source of nutrient load (primarily as phosphates). For the lakes with a catchment occupied by allotment gardens, an elevated trophic status and intensive overgrowth by vegetation (floating forms) is driven by an increased nitrogen load.
The results can be used for planning land and water management activities in North-Western Russia and in other world’s regions with similar environmental conditions.
These results can lay a foundation for creating a region-specific model to predict trends in eutrophication and overgrowth of small shallow lakes.
