Sarmanov Aibek, Matela Mikołaj, Sultanov Yerzhan, Sergaliyev Nurlan, Obolewski Krystian
Department of Science and Postgraduate Training, Makhambet Utemisov West Kazakhstan University, 090000, Uralsk, Republic of Kazakhstan.
Department of Hydrobiology, Kazimierz Wielki University, 85-090, Bydgoszcz, Poland.
Sci Rep. 2024 Dec 23;14(1):30622. doi: 10.1038/s41598-024-82527-z.
Shallow lakes, including those located at the border between Europe and Asia (Kazakhstan), have become very prone to increasing salinity because of climate change. Most of the study area is in one of the fastest-warming parts of the globe. Our research, conducted in four lakes varying in water salinity level and located in western Kazakhstan in the steppe, semi-desert, and desert zones, can be used to predict biodiversity as indicators of the natural potential of ecosystems. This was achieved by assessing the associations of invertebrate communities with environmental conditions based on data collected during nine seasonal measurement campaigns (in May, July, and September of 2019, 2020, and 2021). The multidimensional scaling (nMDS) of biotic and abiotic data enabled us to identify lakes as freshwater (1), oligohaline (1), and mesohaline (2). The key classifier was biotope salinity, irrespective of lake location in the steppe, semi-desert, or desert zones. Twenty-nine taxa were identified in the freshwater lake, 37 in the oligohaline, and 24-28 in the mesohaline lake; these accounted for ~ 80% of their estimated taxonomic composition, according to Species Accumulation Curves (SAC). The differences in the structure of benthic invertebrate assemblages revealed between the lakes are mainly concerned with the density and, to a lesser extent, the diversity of communities (Simpson index). As the salinity of the waters increased, the proportion of Diptera larvae significantly increased, and that of Ephemeroptera larvae decreased. Sigara assimilis, accompanied by Sphaeromas sp., Chironomus sp., and Saeharia sp., proved strongly resistant to increased water salinity. Among the studied lakes, the semi-desert lake Balykty Sarkyl (β-mesohaline) is strongly threatened by biodiversity degradation due to unfavourable climatic conditions. Time series analysis for Lake Edilsor (α-mesohaline) shows that it underwent the most rapid salinisation, which has increased the number of taxa tolerant to this predictor (mainly Diptera larvae). The results confirm that detailed taxonomic assessment (including time series) can significantly improve our understanding of lake changes with increasing salinity caused by climate change and/or other stressors.
包括位于欧亚大陆边界（哈萨克斯坦）的湖泊在内的浅水湖泊，由于气候变化，盐度极易上升。研究区域的大部分地区位于全球变暖最快的地区之一。我们在哈萨克斯坦西部草原、半沙漠和沙漠地带的四个盐度不同的湖泊中进行了研究，这些研究可用于预测生物多样性，作为生态系统自然潜力的指标。这是通过根据在九次季节性测量活动（2019年、2020年和2021年的5月、7月和9月）收集的数据，评估无脊椎动物群落与环境条件之间的关联来实现的。生物和非生物数据的多维标度分析（nMDS）使我们能够将湖泊确定为淡水湖（1个）、寡盐湖（1个）和中盐湖（2个）。关键分类因素是生物群落盐度，而与湖泊位于草原、半沙漠还是沙漠地带无关。在淡水湖中鉴定出29个分类单元，在寡盐湖中鉴定出37个，在中盐湖中鉴定出24 - 28个；根据物种累积曲线（SAC），这些分类单元约占其估计分类组成的80%。湖泊之间底栖无脊椎动物群落结构的差异主要与群落密度有关，在较小程度上与群落多样性（辛普森指数）有关。随着水体盐度的增加，双翅目幼虫的比例显著增加，蜉蝣目幼虫的比例下降。西格阿蠓（Sigara assimilis）与球马陆属（Sphaeromas sp.）、摇蚊属（Chironomus sp.）和萨哈里亚属（Saeharia sp.）相伴，对水体盐度增加具有很强的抵抗力。在所研究的湖泊中，半沙漠湖泊巴利克蒂萨尔基湖（Balykty Sarkyl，β - 中盐湖）由于不利的气候条件，正受到生物多样性退化的严重威胁。对埃迪尔索尔湖（Edilsor，α - 中盐湖）的时间序列分析表明，该湖经历了最快速的盐化过程，这增加了对该预测因素耐受的分类单元数量（主要是双翅目幼虫）。结果证实，详细的分类评估（包括时间序列）可以显著提高我们对气候变化和/或其他压力源导致盐度增加时湖泊变化的理解。
