Scientific publications

The authors analyze changes in the structure, seasonal and long-term dynamics of zooplankton in Lake Vozhe (Vologda Region) for the entire research period (1972 – 2019). The community contains 158 species (Rotifera – 70, Cladocera – 64, Copepoda – 24). There are no invasive species among zooplankters. Due to the shallowness of the reservoir, phytophilic and coastal organisms are widely represented. The composition of the dominant zooplankton complex is relatively stable during the entire research period. In recent decades, the loss of pelagic species (Asplanchna priodonta, Conochilus unicornis, Limnosida frontosa) and an increase in the proportion of rotifers have been noted. The seasonal dynamics of the lake zooplankton is stable and is characterized by two peaks of abundance and biomass in May and July. The abundance of zooplankton at the beginning of the growing season depends on thermal conditions. The abundance and biomass of cladocerans increases towards the end of the growing season, while the abundance of cyclops decreases. The proportion of rotifers changes depending on the density of large Asplanchna priodonta and small representatives of the Brachionidae family. The spatial differences of the community are most pronounced in the summer and are determined by wind mixing and the spread of macrophyte thickets. Long-term changes in the zooplankton of the lake are associated with the specificity of anthropogenic influence. The cancellation of non-water fishing caused the expansion of the thicket zone in some parts of the lake. The increase in the number of small fish intensified the grazing of large and numerous zooplankters. This contributed to an increase in the abundance of zooplankton in thickets, in particular, in shallow bays in the eastern part of the lake, and simplified the structure of the dominant complex. The decrease in the nutrient load on the lake catchment determined the decrease in the level of zooplankton development in the 1990s and 2000s. In the last decade, there has been an increase in the average abundance and biomass of zooplankton.