NATURAL SCIENCES

Journal of fundamental
and
applied researches

Changes occurring at the start of the XXI century in plant communities located in bottom-land spawning sites within the lower Volga delta lower area of the Astrakhan state reserve territory

2013. №1, pp. 18-23

Podolyako Stepan A. - Research Associate, Astrakhan State Reserve, 119 Embankment of the river Tsarev St., Astrakhan, 414021, Russian Federation, philopator@bk.ru

Vasileva Lidiya M. - D.Sc. (Agriculturae), Director, Research and Education Center “Sturgeon”, 14a Volodarskiy St., Astrakhan, 414000, Russian Federation, bios94@mail.ru

The paper reveals changes which occurred at the beginning of the 21st century in plant communities located in bottom-land spawning sites within the lower Volga delta area (Astrakhan State Reserve territory). The changes affected the reproductive efficiency of marketable fish species such as the common carp, Caspian roach and bream, whose numbers have decreased in comparison to previous years. According to the critique, the changes happened due to the following reasons: adverse hydrological and hydrothermal regimes, reduction of the high-water period, degradation of food reserves, reduction of spawning habitat and appearance of weed plants in the spawning sites, with the latter aspect of crucial importance. At this stage, the study adds that changes in the species composition of plant communities in the spawning sites tend to enable better prediction of the conditions of spawning sites and the volume of marketable hydrobiont reproduction. The goal of the research was to provide an up-to-date assessment on the spawning sites’ condition with respect to the species composition of its plant communities. The study of the plant associations, the document relates, took place in 2012 in the territory of the Volga Delta bottom-land spawning sites – Damchikskiy (Western part) and Obzhorovskiy (Eastern part) areas of the Astrakhan State Reserve. The overall objective was to compare the obtained results with similar data from the year 2001. The acquired data was used to create useful guidelines for the spawning sites for reproduction of the valuable, marketable semi-anadromous fish species. In conclusion, the commentary indicates that such researches took place within the Astrakhan State Reserve territory for the first time in this century, with the results to be used to solve issues dealing with preservation and restoration of fish resources in the Volga-Caspian basin.

Key words: spawning sites,Volga delta,Astrakhan State Reserve,reproduction,valuable fish species,plant associations