Effect of Geographical Location on Species Composition, Vegetation Structure, Diversity and Phytoindicative Characteristics in Pine Forests

Abstract

The subject of this study is the influence of geographical location on floristic composition, horizontal structure, biomass, species richness, species diversity and values of phytoindicators of the herb layer in pine and mixed pine forest communities along a climatic gradient. Geographical longitude was used as a synthetic measure of geographical position. Studies were conducted on 17 plots. The westernmost plot was located at 12°25′48″E and 53°6′7″N, the easternmost plot was situated at 32°37′37″E and 53°20′56″N. All study areas were representatives of the Dicrano–Pinion alliance and included two communities of pine forest ( Peucedano-Pinetum and Leucobryo-Pinetum) as well as the community of mixed pine forest ( Querco roboris-Pinetum). Plots fell into two geographical groups: suboceanic and subcontinental. Three types of ground flora were identified: one dominated by a cover of mosses, the second dominated by dwarf shrubs, and the third dominated by species of grass. The ground cover biomass on the west-east transect ranged from 49 to 544 g m −2. There is a statistically significant correlation between geographical longitude of the stand and biomass of mosses as well as of total biomass of the ground cover along the transect. On the basis of Ellenberg’s indices the vegetation on consecutive sample plots is not strongly differentiated. All sites on the transect occur on dry, strongly or slightly acidic soil, with low nitrogen content. Values for the index of continentality K reflect the climatic differentiation from west to east. The number of herb layer species increases eastward, and all diversity indices are strongly correlated with the longitude. The relative number of chamephytes and therophytes is positively correlated with the longitude. In pine forests there is a general tendency for the number of scleromorphic species to decrease (and of mesomorphic species to increase) westward. There is also a general tendency for meadow species to increase westward.