Coenomorphs as phytometers of biotopes

Abstract

The article describes the A.L. Belgard system of vascular plant species coenomorphs as indicators of biotopes by using standardized Y.P. Didukh phytometer scales for 12 environmental factors. The classification and ordination of coenomorphs in the phytometer space was performed by using algorithms of discriminant analysis. The analysis is based on 2,186 species of the vascular plant flora of Ukraine. The classification accuracy was around 80% and above, the least homogenous was the petrophyte coenomorph. The validity of identification of ruderal coenomorphs was proved as an indicator of biotopes with increased content of soil nitrogen. Analysis of the a posteriori probability of species attribution to a coenomorph supports the validity of distinguishing transitional coenomorphs. Their number is small and each group contains a small number of species. The principal factors of classifying species by coenomorph are (in descending order of significance): minimum soil moisture, minimum light (shade), impoverishment of salts in the soil solution, high porosity of soil and impoverishment of carbonates of calcium in the soil and maximum values for radiation balance. The analysis of the distribution of coenomorphs in the space of the square of Mahalanobis distances and the ordination in the discriminant functions axis has determined the ranking of coenomorph of biotope and coenotic substitution: soil moisture (first discriminant function), radiation balance and shade (second discriminant function), salt regime and soil aeration (third discriminant function). For the vegetation of Ukraine this ordination of coenomorphs corresponds to the zonal factors of the distribution of biotopes and their limiting factors and the factors determining A.L. Belgard’s typology of natural and artificial forests: soil moisture, salinity of the soil solution, light conditions. The coenomorph optima for the principal factors have been defined in phytometer scales. This allows coenomorphs to be used as biotope phytometers and provides a preliminary assessment of those species whose place in the scales has not yet been determined. Analysis of posterior probabilities enabled us to determine the transitional coenomorphs, which are typical for ecotones between zonal and intrazonal vegetational ecosystems of Ukraine.