Research Center of Hydrobiology, Department of Ecology, Jinan University, Guangzhou 510632, China; Research Center of Tropical and Subtropical Aquatic Ecological Engineering, Ministry of Education Engineering, Jinan University, Guangzhou 510632, China.
Guangzhou Water Planning Survey and Design Co. Ltd, Guangzhou 510640, China.
Sci Total Environ. 2022 Sep 10;838(Pt 3):156156. doi: 10.1016/j.scitotenv.2022.156156. Epub 2022 May 21.
Rivers in urbanised cities are often polluted, black, and odorous, with poor water quality and deteriorated ecology. Despite many river restoration studies, assessments of ecological responses to river restoration practices remain scant. Benthic animals are useful biological indicators showing the change and succession of river ecosystems; however, previous studies have mainly focussed on a few target species without considering overall ecosystem integrity. Here, we used a multi-index biological assessment method, benthic index of biological integrity (B-IBI) to assess ecological responses to river restoration of the Shahe River in subtropical region of China. Spatiotemporal changes in the macrobenthos community structure after restoration were monitored to explore species succession. We found that the number of macrobenthos species increased from 16 to 42, with the emergence of some pollution-sensitive species during the restoration period. Molluscs showed widespread recovery, and their relative proportions almost doubled from 12.5% to 24.4%. Oligochaetes and chironomids were the pioneer species in the recovering communities, while gastropod molluscs and pollution-sensitive aquatic insects were transitional species that first settled during the initial recovery period. Based on our survey data, 25 candidate metrics were selected, and five core metrics (total taxa, Simpson diversity index, percentage of crustaceans and molluscs, percentage of predators, and percentage of collector-gatherers) were identified after screening to establish the B-IBI. Our analysis revealed a distinct improvement in the overall health of the river, with the proportions of "excellent" and "good" sites increasing from zero to 28.6% and from 14.3% to 42.9%, respectively. A correlation analysis indicated that water flow, molluscs, and total phosphorus content were the three drivers of ecological recovery in the Shahe River. Overall, our study demonstrates the importance of governance and restoration of rivers in tropical and subtropical cities, and provides valuable evidence that can guide the design and evaluation of river restoration works.
城市河流通常受到污染，呈现黑色，散发恶臭，水质较差，生态恶化。尽管有许多河流修复研究，但对生态响应的评估仍然很少。底栖动物是反映河流生态系统变化和演替的有用生物指标，但以往的研究主要集中在少数目标物种上，而没有考虑到整体生态完整性。在这里，我们使用多指标生物评估方法，即底栖生物完整性指数（B-IBI）来评估中国亚热带地区沙河河流修复的生态响应。监测了恢复后底栖动物群落结构的时空变化，以探索物种演替。我们发现，底栖动物物种数量从 16 种增加到 42 种，在恢复期间出现了一些污染敏感物种。软体动物广泛恢复，其相对比例从 12.5%增加到 24.4%。寡毛类和摇蚊科是恢复群落中的先锋种，而腹足纲软体动物和污染敏感水生昆虫是在初始恢复阶段首先定居的过渡种。根据我们的调查数据，选择了 25 个候选指标，经过筛选后确定了 5 个核心指标（总类群、辛普森多样性指数、甲壳类和软体动物的百分比、捕食者的百分比和收集者的百分比），以建立 B-IBI。我们的分析表明，河流的整体健康状况明显改善，“优秀”和“良好”站点的比例从 0 增加到 28.6%，从 14.3%增加到 42.9%。相关性分析表明，水流、软体动物和总磷含量是沙河生态恢复的三个驱动因素。总的来说，我们的研究表明了热带和亚热带城市河流治理和修复的重要性，并提供了宝贵的证据，可以指导河流修复工程的设计和评估。
