Ulanova S.S., Fedorova N.L., Bembeeyeva О.G., Dzhambinov V.Е., Chetyrev L.P. Nature Complexes of the Arshan-Zelmen Water Reservoir Coast // Ecosystems: ecology and dynamics. No 1. 2025. P. 5-34. | Abstract | PDF | Reference
- Physical-geographical map of the research area (scale 1 cm : 25 km)
- Mass death of fish in the Arshan-Zelmen reservoir, 18/10/2020 (photo by S.S. Ulanova)
- In the center – the Spirobassia hirsuta-Salicornia perennans community, on the left and right – strips of tamarisk undergrowth, surrounded by tall=- tamarisks in a fluctuation block in an ecotone system on the coast in the central part of the Arshan-Zelmen reservoir, September 2023 (photo by N.L. Fedorova)
- Ecotone zone of the dam part of the Arshan-Zelmen reservoir, dynamic block, community of Tamarix ramosissima + T. laxa–Chorispora tenella, Cardaria draba, April 2024 (photo by N.L. Fedorova)
- Ecotone zone of the dam part of the Arshan-Zelmen reservoir, distant block, second belt, Tamarix laxa–Artemisia santonica, A. austriaca+Poa bulbosa community, September 2024 (photo by N.L. Fedorova).
- Ecotone zone of the dam part of the Arshan-Zelmen reservoir, marginal block, community of Artemisia lerchiana, A. santonica, A. taurica+Stipa sareptana, S. lessingiana+Poa bulbosa, April 2024 (photo by N.L. Fedorova)
In the Republic of Kalmykia, water reservoirs were created in the 1930s-1950s. However, their hydrological regimes, water quality, methods of use and surrounding landscapes have undergone massive changes since then. Unfortunately, no studies have been carried out to show specific changes in the quality of water and territories adjacent to the reservoirs that take place due to their creation and use. There is also an absence of studies on the current state of natural complexes along the coasts of reservoirs, as well as transformation of various components of their ecosystems (e.g. vegetation, soils, relief and biota). Therefore, the goal of our work was to characterize the current state of natural complexes on the coast of the Arshan-Zelmen water reservoir. In this study, we decided to identify and characterize the current state and changes in various indicators of the reservoir, such as the area of its water surface, mineralization of its water, features of its structural organization and functioning of ecotone systems on its coast based on the monitoring studies of 2001-2023. We used modern methods of landscape and ecological research, geobotanical indication, topological profiling, statistical processing, geoinformation technologies with the use of relevant materials of space imagery, and methods of the ecotone concept created by V.S. Zaletaev (1997). Analysis of the average long-term values of the water surface area for 1990-2023, carried out on the basis of remote sensing imagery, showed a threefold decrease in the size of the reservoir. The minimum and maximum levels of the reservoir were 25.0 m in 2021, and 29.6 m in 1990, while the maximum level change during the study period was 4.6 m. Since the creation of the reservoir, the mineralization of its surface waters had gradually increased from 2.4 g/dm3 in the 1980s to 9.4-21.72 g/dm3 in the spring of 2022, and then to 14.9-68.62 g/dm3 in the autumn of 2022. With its mineralization increasing in 2001-2017, the reservoir lost its irrigation purpose, and was used for large and small cattle until 2019. With a further salinity increase (to the level of brine) in 2020-2022, the use of this reservoir ceased completely. We revealed some features of the structural and functional organization of ecotone systems on the coast of the reservoir based on the monitoring of 2001-2023 that showed that there were targeted changes in the blocks of ecotone systems: the fluctuation block expanded up to 150 m due to shallowing; in the fluctuation and dynamic blocks, the mineralization of surface water and groundwater increased by 2.5-4 times, the abundance of halophytes and weeds increased as well. Groundwater in the ecotone zone is fed by the reservoir, as evidenced by groundwater running the deeper the further it flows from the reservoir’s rim, and by its increasing mineralization. Our study has shown that profound changes occurred in the Arshan-Zelmen reservoir and the surrounding landscapes when its water level dropped by 4.6 m.
Keywords: artificial water reservoirs, arid zone, Republic of Kalmykia, Arshan-Zelmen water reservoir, area, water mineralization, water–land ecotone systems.
DOI: 10.24412/2542-2006-2025-1-5-34
EDN: EIJLLO