University proceedings. Volga region. Natural sciences

Abstract

Background.We suppose a comprehensive description of macrophyte communities using both the traditional allocation of dominant and subdominant species and an integral assessment of species diversity using the natural logarithmic Shannon index, the Pielou evenness index, and the Simpson diversity index. Materials and methods.Three major water bodies of Arzamas were studied: the Tesha River, the Shamka stream, and the Smirnovsky Pond, which are subject to complex anthropogenic impact. The coastal-aquatic grass cover has a large zonal differentiation, therefore, the communities of shoreline, as well as submerged aquatic and floating vegetation are described separately. In the shoreline three sample plots were studied in each biotope of 3 × 4 m2 (total – 36 m2), in the water, descriptions were carried out in the surface water layer up to 2.5 m deep on three sample plots of 3 × 4 m2 (total – 36 m2). Dominant and subdominant species were identified according to the 5-point quadratic-transformed abundance scale of E. L. Lyubarsky. The anthropogenic load is assessed using a set of herbaceous macrophyte indicative parameters: total projective cover, relative abundance and composition of mass species, and the proportion of ruderal and adventitious species in the floristic and cenotic spectra. Results.The peculiarity of the studied water bodies is their drainage by highly mineralized groundwater, increased hardness, and high sulfate content in the water.The species structure of aquatic vegetation is generally more spatially evened than that of the shoreline herbaceous vegetation. A very high proportion of ruderal species in the floristic and community spectra of the vegetation of the Smirnov Pond, the Shamka stream and the Tesha River (sections No. 3 and No. 4) indicate an intense anthropogenic load caused by both economic transformation and littering of the banks, as well as recreational impact. A critical state of extremely disturbed and replaced by ruderal species of shoreline macrophyte communities has developed in section No. 3 of the Tesha River and No. 6 of the Shamka stream. Conclusions. In the conditions of pollution of water bodies of Arzamas the dominance or mass development of species: Glyceria maxima (Hartm.) Holmb., Alisma plantago- aquatica L., Juncus compressus Jacq, Núphar lútea L indicates intensive anthropogenic eutrophication and municipal pollution. Under intensive anthropogenic load, weed vegetation prevails in the coastal strip: Chenopodium album L., Arctium tomentosum L., Urtica dioica L., Potentilla anserina L., weed-meadow species are abundant.

Keywords

• coastal and aquatic vegetation
• species evenness
• species diversity indices
• floristic richness
• total projective cover