COMPARATIVE ANALYSIS OF LIFE FORMS SPECIAS RICHNESS OF VASCULAR PLANTS IN THE MIDDLE VOLGA REGION
P. A. Shary1, L. S. Sharaya2, A.V. Ivanova2, N. V. Kostina2, G. S. Rozenberg2
1Institute of Physiochemical and Biological Problems in Soil Science of RAS, Pushchino, Russia
2Institute of Volga Basin Ecology of RAS, Tolyatti, Russia
Keywords: видовое богатство сосудистых растений, спектры жизненных форм, климат, энергия, освещенность склонов, множественная регрессия, species richness of vascular plants, life form spectrum, climate, energy, slope insolation, multiple regression
Abstract
A single quantitative parameter, d , is introduced for the spectrum of seven life forms (LFs) that characterizes proportions of their species richness (SR) in the Middle Volga region for 25 plots of 100 km2 each. It is substantiated that d grows with moisture. All significant links between SRs of various LFs were positive. However, links of different signs were found between proportions of species numbers of each LF from the total SR, or relative species richness (RSR). For example, a strong negative link was observed between RSR of dominant in the region LF, hemicryptophytes, and annual grasses (therophytes). Using regression models, we describe specific relations between SR and RSR of the seven LFs and climate and topography. Within the region, precipitation was more important for some LFs, and temperature for others. The links were stronger when insolation was taken into account, but links with it may have different signs for SR of various LFs. Maps of SR and RSR for hemicryptophytes and therophytes were calculated using regression models. These maps demonstrated subdivision of these LFs in space: hemicryptophytes are related to flat areas near water divides, while therophytes are related to northeastern slopes. The main factors that differentiate these LFs in space were solar energy and precipitation in March and in winter. The subdivision of these LFs potentially results in diminishing of competition between them.
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