[Evolutionary saturation of species pool in present high mountain plant communities of Western Caucasus]

The relative level of evolutionary saturation/nonsaturation of high mountain plant communities in Western Caucasus was defined by analysis of correlation between their local richness (LR) and size of species pool (SP). It is expected that if compared biotas are differently distant from the point of equilibrium one should look forward to a significant variation in correlation between LR and SP determined with the greater sensitivity of LR in comparison with SP in respect of abiotic factors. The lower is correlation LR/SP the greater is level of evolutionary nonsaturation in analysed communities. The results of analysis confirm the assumptions on 1. incompleteness of flora development in the high mountain zone in Western Caucasus, 2. different ages of alpine and subalpine communities, 3. different time necessary to attain the equilibrium with species pools of communities formed under extreme and more favourable conditions, 4. dependence of temps of flora development on the isolation of mountain ridges and massifs. The species pools of the most extreme alpine ecotope communities characterized by low environment capacity (plant groups of moving taluses, low-species communities of alpine tapises, meadows and grounds) as well as the most of subalpine communities are evolutionary saturated or close to this condition. Development of species pools of alpine multi-species low-grass meadows as well as some of subalpine middle-grass meadows evidently is not completed yet. They can be considered to be the most probable places of the new species appearance by speciation or immigration from another Caucasus regions.