Effect Exercised by Climate on the Taxonomic Diversity of Vascular Plants in the Middle Volga Region

Abstract

Analysis of relationships between the richness of three taxonomic ranks of vascular plants in the Middle Volga region and climate showed that the climatic factor explains 74% of variance in the number of species and families and 76% of variance in the number of genera. Taxonomic parameters of a floristic sample collected on 25 polygons 100 km2 in size each were compared with climatic parameters and their functions. Multiple regression models were produced for the three taxonomic ranks (numbers of families, genera, and species), and maps have been constructed on the basis of these models. The main predictors were climatic parameters at the beginning of spring and in winter months. Statistically significant correlations between the richness of species, genera, and families and some functions of climatic parameters that are usually excluded from analysis were identified. The essence of these functions is discussed in the context of their effect on snow melting processes in early spring.