Diversity and ecology of algae in the Algeti National Park as a part of the Georgian system of protected areas

Algal communities from the Algeti National Park in eastern Georgia were studied between 2005 and 2008. The algal species diversity comes from 77 algological samples and includes 315 species and infraspecies, which belong to 7 taxonomical divisions. Of these findings, 295 species are reported for the first time in the Algeti National Park and 9 of them are new for Georgia. The most abundant are diatoms, with 220 species. Communities were dominated by Cladophora glomerata (L) Katz. (Chlorophyta), Spirogyra sp. (Charophyta), Ulnaria ulna (Nitzsch) Compere (diatom), and Phormidium autumnale (C.Agardh) R.Trevis. ex Gomont (Cyanobacteria). The index of species diversity per area in the Algeti is 6.89. The comparative floristic and statistical analysis of algal communities from Algeti and 13 other Georgian Natural Reserves, altogether 1063 species, divides the communities into groups of less than or more than 200 species, with diatom or nondiatom domination that correlates with climatic variables. The species diversity in the natural reserves increases from the Black Sea coast to the east, a movement that corresponds to a similar increase in altitude. In this study, 3 floristic groups are recognized: mountainous areas, lowlands, and piedmonts. The most species-rich communities are found in extreme environments. A correlation of algal diversity with environmental conditions shows that the altitude-dependent regional climatic variables and the lowest winter air temperature in particular, are the major factors. The index of infraspecies variation in each reserve is a small range (1.01-1.15) and shown to be a result of constant altitude combined with seasonal climatic fluctuations. The diversity indices and bioindication analysis reflect a moderate level of anthropogenic disturbance for the protected areas.