PRODUCTIVITY ASSESSMENT OF VARIOUS PLANT COMMUNITIES AT URANIUM MINE SITES IN CENTRAL KAZAKHSTAN

Abstract

Examining the overgrowth of dumps, techno-soils, and areas containing waste products of uranium mines is vital for understanding the dynamic features of vegetation cover in technogenic landscapes. The main aim of this study was to investigate variations in the plant species composition and their productivity in dumps and technological areas and the intensity of soil ionizing radiations under varying environmental conditions based on the Shantobe Uranium Deposit, Kazakhstan. The vegetation at the waste dumps and technogenic sites is in the early stages of syngenesis and is representative of pioneer and group-thicket communities. Adverse ecological conditions associated with intense sulfate salinization formation thrive at the technological sites. However, the floristic composition is illustrative of highly resistant species (Calamagrostis epigejos and Phragmites australis) and secondary species. Typically the formation of steppe zone plant communities of Kazakhstan does not occur in these sites. The productivity of the recultivated dump and banks of the former uranium mine is quite high at 120–150 g/m2, which matches the meadow-ruderal communities of Northern Kazakhstan. However, the lowest productivity of 30–37 g/m2 emerged in the non-recultivated and partially processed sulfuric acid heap leaching stacks containing uranium ore, which create exceedingly unfavorable conditions for the establishment of crop plants. Several plant species identified as self-seeding live in partially processed piles of sulfuric acid heap-leaching uranium ores with a sufficient level of resistance to survive in soil with high levels of sulfate-containing salts and ionizing radiation of 1200–1400 μR/hr. These facts can authenticate to consider the possibility of growing these plant species in the artificial grassing of uranium-containing dumps to create herbage.