Influence of Solar Radiation on the Distribution of Halophytes in Plant Communities

A correlation between the proportions of halophyte life forms (LFs) and slope insolation in the saline soils of Samara oblast is analyzed. Perennial grasses (hemicryptophytes) are dominant in plant communities on slightly saline and nonsaline soils. These conditions give them advantages over annual grasses (therophytes) in competing for light and heat. An increase in the degree of salinity of ecotope soils in the plant community leads to a growth in the proportion of therophytes, which successfully compete with hemicryptophytes for light under these conditions. It is shown that hemicryptophytes and therophytes change the pattern of their correlation with the radiation index even within the same study area, depending on soil salinity. Regression models using slope insolation and topographic characteristics as predictors account for over 74% of the variance in the number of LF species.