Ecological determinants of algal communities of different types of ecosystems

Abstract

The results of studies of the environmental regularities of the formation of algal communities in soils of various ecosystems in the south of Ukraine are presented. 26 forest, 11 steppe and 3 saline ecosystems were investigated. The research has established the species richness of algae in each ecosystem and produced a multidimensional ordination of algal communities based on the analysis of the main components to clarify the factors that determine the composition of algal communities. The research has established the species richness of algae in each ecosystem and produced a multidimensional ordination of algal communities based on the analysis of the main components to clarify the factors that determine the composition of algal communities. Predictors determined by edaphic conditions and phytocenotic interactions associated primarily with edificators of ecosystems were used for the analysis. The ecological space of the studied ecosystems was formed by four main factors with eigenvalues greater than one, which explained 81.4% of the total variance. PC1 (34.82% of variance) is associated with the type of ecosystem and such edaphic parameters as pH, the availability of moisture in the habitat, and soil mineralization. PC2 (21.98%) reflects changes in the gradients of trophicity (humus content) and granulometric composition of soils. PC3 and PC4 additionally explain 16.04% and 9.27% of the total data variance, respectively. Their values mainly depend on the mineralization, trophicity, and moisture supply of edaphotopes, which, at the level of the composition of algae, is obviously associated with the heterogeneity of the ecological preferences of the algal species themselves, as well as the variability of ecological niches of ecosystems, due to which there are species more typical for other types of ecosystems in the communities. The use of the factor rotation procedure by the Varimax normalized method made it possible to concretize the taxa most associated with the main components: PC1 indicates the various Cyanobacteria species, PC2 – Chlorophyta, Streptophyta and Eustigmatophyceae, PC3 – Xanthophyceae and Euglenozoa, PC4 – Bacillariophyceae.