Medard Lake, located in the western part of the Czech Republic, covers an area of 490 hectares and has a maximum depth of 50 meters. It serves as a unique long-term ecological research area (LTER) for studying ecological processes in large, restored lentic ecosystems. The ongoing research focuses on the effects of intra- and interspecific interactions on fish community succession, the impacts of anthropogenic activities and long-term changes on water quality, the influence of submerged macrophytes on trophic relationships and fish distribution in deep lakes, and the composition of periphyton as well as the structure and biomass of phytoplankton.

The lake faces changes in trophic conditions, such as eutrophication and alterations in the trophic web structure, including a decrease in the biomass of piscivorous fish. Global changes, particularly longer periods of high temperatures, contribute to blue-green algae blooms and lower water levels.

Medard Lake is a valuable resource for tourism, offering opportunities for water sports and recreational fishing.

Efforts have been made to maintain a low nutrient load and ensure a typologically appropriate fish community with a high proportion of predatory fish species.