Abstract:

The aquatic ecological environment is a key component of comprehensive national water management, and can provide critical ecological services. With the acceleration of urbanization and water resource consumption by industry and life, sewage discharge loading has been observed. Therefore, water ecological and environmental problems have received considerable attention. This study focuses on the Lushui River Basin in the Zhuzhou area. Eight sections from the upstream region and two representative reservoirs were distributed to evaluate the spatial heterogeneity of habitat and aquatic biological indicators during a typical dry season in 2022. The results showed that the sediments of most sections were primarily composed of gravel and fine sand but with marked soil attachment to the overall gravel, which may be related to the surrounding soil erosion and high water turbidity, except for the tributary Tieshui. The two reservoirs exhibited clear sandy substrates, indicating good habitat conditions. The best riverbed quality was observed in the section where Tieshui entered Lushui, which was dominated by fine sand without a significant silt attachment. Six 6 phyla of phytoplankton, four phyla of zooplankton, and three phyla of macrobenthic invertebrates were identified. The average cell density of phytoplankton was 0.649×10⁶ cell·L^-1, with an average biomass of 0.996 mg·L^-1, while that of zooplankton was 147 ind·L^-1, with an average biomass of 0.126 mg·L^-1. The biomass and density of phytoplankton and zooplankton in the Sandaoshi and Xianjing sections in the middle and lower reaches of densely populated areas were significantly higher than those at other monitoring points, and the health status of the habitat was relatively poor, which may be related to human vegetable planting activities on both sides of the river and early rain runoff from urban areas. The biodiversity and habitat status of the reservoir were better than those of the river section were. The distribution of microbenthic invertebrates is affected by the degree of preference for the microenvironment and there is no obvious spatial law of biomass and diversity. The evaluation results of the Shannon-Wiener and BMWP indices showed that the water ecological health level and biodiversity of the Lushui Basin require further improvement. There was no significant correlation between the CWQI value of the water quality index and aquatic biological indicators, but the correlation between total phosphorus and water ecological indicators of a single water quality index was relatively high, which needs to be paid more attention in the future. The results provide a scientific basis for water habitat, water ecology, and the three-water control and protection of water resources in the Lushui River Basin.

Key words: Lushui basin, habitat, aquatic organism, water ecology, spatial characteristics, water ecological health assessment

摘要：

随着城镇化水平的不断加快，工业、生活等用水量逐渐增加，污水排放量的与日俱增及其引发的水生态环境问题日益受到重视。以渌水流域株洲区域为研究对象，从上游至下游共布设8个断面与2个代表水库，开展了2022年典型枯水期的生境与水生生物指标的空间异质性特征评价研究。结果显示，渌水沿程底质以砾石、泥沙为主，但总体砾石上附着泥土特征明显，可能与水土流失造成的水体浑浊有关，其中渌水支流的铁水底质以细沙粒为主，无明显淤泥附着，水质较好。2座水库底质以细沙粒为主，砂砾清晰，生境状况良好。研究共鉴定出浮游植物6门，浮游动物4门，底栖动物3门。浮游植物平均细胞密度为0.649×10⁶ cell·L^-1，平均生物量为0.996 mg·L^-1；浮游动物平均密度为147 ind·L^-1，平均生物量为0.126 mg·L^-1。其中中下游人口密集区的三刀石与仙井断面浮游植物、浮游动物生物量与密度明显高于其他点位，且生境健康状况相对较差，可能与河流两岸蔬菜种植、城区初雨汇入等有关。水库生物多样性、生境状况均优于河流断面。大型底栖无脊椎动物受对微环境的喜好程度的影响而分布，其生物量与多样性无明显的空间规律。采用Shannon-Wienner指数及BMWP指数进行水生态健康评价，结果显示渌水流域的水生态健康水平、生物多样性均有待进一步提高；水质综合指数CWQI总值与水生生物指标无显著相关关系，但单项水质指标中的总磷与水生态指标相关性较高，需要重点关注。研究结果可为渌水流域的水生境、水生态和水资源治理与保护提供科学依据。

关键词: 渌水流域, 生境, 水生生物, 水生态, 空间特征, 水生态健康评价