Abstract
The aim of the study was to determine whether biometric features of plants collected from single-species phytocoenoses developing in ponds can be used to describe habitat conditions of these water bodies. The biometric measurements were carried out in 148 field small water bodies at a total of 198 sites. The length of plants, their dry biomass, and volume of plant shoots were analyzed, converted to 1000 dm3 of water. The biometric measurements showed very large differences in individual parameters of different macrophyte species. The biggest differences were found in the length of elodeids and helophytes (from 1 cm to > 900 cm), regardless of trophic conditions. Although the Polish flora is dominated by plants having a wide ecological range, there are species whose parameters correspond to specific habitat fertility. The highest biometric parameters were found for Ceratophyllum submersum, Sparganium erectum, Typha latifolia and Schoenoplectus lacustris in ponds characterized by increased trophic conditions. In contrast, Myriophyllum spp. alone showed a negative correlation with trophic state indices. The trophic effect on the studied parameters becomes more apparent for species with optima in fertile water bodies. The parameters of Ceratophyllum submersum can be considered as the trophic state index (TSI).