Limnetica 37

Mediterranean shallow lakes are affected by many deterioration processes like eutrophication, land-use changes along its drainage basin and climate change. Aquatic plants are expected to reflect the ecological changes of shallow lakes since they are in close contact with the environmental factors. We assessed the influence of climate, land use and local conditions on macrophyte community changes in Sentiz Lake, a steppe water body located in the northwest of Spain, using long term data of local conditions, satellite imagery, orthophotography and climatic series. We found important changes in the environmental drivers of aquatic macrophyte assemblages (e.g. mean depth, water surface area, shore vegetation, mean annual temperature and grassland coverage). Similarly, we found that aquatic macrophyte growth forms responded to different environmental controlling factors: submerged and floating-leaved hydrophytes responded to local conditions, while big helophytes and small helophytes responded to land use and climate, respectively. Overall, our study suggests that management efforts aimed at preserving aquatic macrophyte assemblages of shallow Mediterranean lakes should focus not only on local conditions of each lake but also on their watersheds and climate. Therefore, this study improves the knowledge of the environmental drivers of aquatic macrophyte assemblages of shallow Mediterranean lakes, incorporating long term data of both physical and biological parameters and providing a basic framework for applying management and conservation strategies in these and other similar ecosystems.