Ecological factors shaping cyanobacterial assemblages in a coastal lake system
Abstract
Cyanobacteria are photosynthetic prokaryotes responsible for most of the global primary production, recurrently showing high abundance levels in freshwater ecosystems. Here, we used variation partitioning to quantify the relative effects of environmental (water parameters), biotic (abundance of eukaryotic phytoplankton) and spatial (geographic distance) factors on cyanobacteria distribution, using taxonomic (species and order levels) and functional (Reynolds Functional Groups and life form) approaches in a coastal lake system (southern Brazil). Cyanobacteria distribution was affected by all factors, but mainly by environmental conditions. Overall, environmental and biotic factors were more important in shaping the cyanobacterial distribution using a taxonomic approach than using a functional-group approach. Filamentous cyanobacteria (both heterocystous and non-heterocystous) were influenced mainly by the environmental variables, and coccoid species by the spatial fraction. Our results demonstrate that taxonomic and functional approaches may reflect different responses to ecological factors, thus being complementary for a better understanding of cyanobacterial distribution patterns in lake systems.
