Spatial variation in taxonomic and functional composition of periphytic algae in lakes of Karelian Isthmus

Variation in species and functional structure of periphytic algae community in relation to chemical, physical, climatic and spatial factors was studied in 55 lakes of Karelian Isthmus. To assess factors driving functional structure, all algal species were divided into eight functional groups that differ in cell/colony morphology and attachment mode to the substrate. Variance partitioning analysis showed that environmental factors (chemical and climatic) prevailed over spatial variables in explaining variation in periphyton species structure. On the contrary, periphyton functional structure depended more on spatial variables than on environmental factors (chemical and physical). This suggests that dispersal processes which are dependent on landscape characteristics of the region and hydrological connectivity along individual river networks play a more significant role in spatial variation of functional composition of periphytic algae.