Genus Hydrocharis (Hydrocharitaceae): Ecology of Communities and Their Tolerance to Abiotic Factors.

The genus Hydrocharis L. includes free-floating, occasionally rooted obligate pleistophytes and rooted hydrohelophytes, which are edificators and subedificators in freshwater vegetation communities. How ecologically similar are these closely related species? It has been established that Hydrocharis dubia (Blume) Backer. and H. morsus-ranae L. are facultatively freshwater alkaliphilic mesoeutrophic ortho- and mesoalluviophilic detrito- and psammopelophiles. H. chevalieri (De Wild.) is ecologically isolated; it is a freshwater acidoneutrophilic meso-, mesoeutrophic, ortho-mesoalluvialophilic species indifferent to the mechanical composition of bottom sediments. The coenocomplex of H. chevalieri is characterized by the abundance of helophyte communities; the key role in the composition of the coenocomplex of two other species is played by hydatophyte and pleistophyte communities. Communities with species of the genus Hydrocharis have simple synmorphology, a relatively high species richness, and a high proportion of low-abundance species. [ABSTRACT FROM AUTHOR]