Landscape structure and habitat composition in reservoirs, lakes, and rivers

We compared reservoirs that were proposed to be included in the Greek Natura 2000 network of protected sites, with natural lakes and rivers from the same network. We analyzed landscape spatial pattern, habitat type composition, and spatial pattern of human activities. We found that the landscapes of reservoirs are distinct from those of rivers and natural lakes. More specifically, the reservoir water bodies were characterized by a more complex shape than the water bodies of rivers and lakes. Furthermore, based upon the landscape spatial pattern of the entire protected area, we could clearly discriminate among the three aquatic ecosystem types. It was also possible to discriminate these ecosystem types based upon the habitat composition of the surrounding landscape. The habitat composition among the different sites showed low similarity. Human presence in all sites was documented, but its spatial pattern was not differentiated among the three aquatic ecosystem types. The results highlight the ambiguous nature of reservoirs; thus, we advocate the need for specific management measures for reservoirs that will accomplish both their intended purpose and the conservation of habitat composition and landscape structure.