Habitat variability of the phytocoenoses of Isoeto-Lobelietum in Poland

摘要

A comparative analysis of the habitats of the two main subassociations of Isoeto-Lobelietum, i.e. Isoeto-Lobelietum lobelietosum and Isoeto-Lobelietum isoetetosum, was conducted. It is demonstrated that the phytocoenoses of Isoeto-Lobelietum isoetetosum occupy not only deeper sites of the lake littoral but they are also restricted to more acidic soft waters richer in Cl, NH_4—N, SO_4 and Na but poorer in total Fe and Ca than those of Isoeto-Lobelietum lobelietosum. The substrates of Isoeto-Lobelietum isoetetosum are more acidic and richer in organic matter, various forms of N, PO4-P, K, total Fe, Na, Cl, and Mg, but generally poorer in SO_4. The results obtained in Poland indicate that the present syntaxonomic status of Isoeto-Lobelietum evidentlyneeds further clarification. The phytocoenoses of Lobelia dortmanna L, and those of Isoetes lacustris L. can be classified as distinct associations i.e. Lobelietum dormannae and Isoetetum lacustris