Species-area relationships for aquatic biota in several shallow lakes from the Fizeș Valley (Transylvania, Romania).

Species-area relationships (SAR) for aquatic invertebrates and phytoplankton were investigated in several shallow lakes from the Fizeș River catchment area. The lakes differed in their morphometric, physical-chemical, biotic and habitat characteristics, with two constant distinctive clusters: the lakes from the main river course, highly exploited for fish farming and generally characterized by higher organic and nutrient loads, and the lakes from the river tributaries, with better environmental conditions, increased depth and lower exploitation intensities. Lake area was a poor predictor of taxon richness for lacustrine invertebrates. Low-intensity exploitation regime, the presence of submerged vegetation, lake depth and natural land use in the catchment area represented the most important independent variables explaining the number of taxa for both planktonic and benthic invertebrates. In case of phytoplankton, however, lake area was an important predictor for taxon richness. Our results represent the first holistic approach to investigating SAR patterns of aquatic biota in natural and man-made lakes from the region. [ABSTRACT FROM AUTHOR]