Some Aspects of the Biology of Sparganium (Typhaceae) in the Mouth Areas of Reservoir Tributaries

Based on the study of three zones (free flow, estuarine and reservoir) transition sections tributaries of the plain reservoir, various aspects of the biology and ecology of three representatives of the genus Sparganium were examined. It was demonstrated that S. emersum, thanks to its high ecological plasticity, forms stands in all transitional zones of tributaries. Sparganium erectum participates in the formation of the vegetation cover in the estuarine and littoral zones of the reservoir, while S. microcarpum is not found in the littoral zone of the reservoir. It was shown that the latter two taxa are particularly sensitive to changes in the water level regime, which affects their ability to maintain their positions in phytocenoses. Using Sparganium as an example, it was established that the influence of the water level in the zone of river water discharge has an impact on the timing of reaching maximum biomass values, both in the free-flowing river zones and in their estuarine areas. It was found that the populations of S. emersum that achieve the greatest phytomass grow in the mouth areas of the reservoir tributaries, S. microcarpum, in the free flow zone of rivers, and S. erectum, in the mouth areas of rivers and in the littoral zone of the reservoir.