Shallow lakes of the middle-lower reaches of Changjiang(Yangtze)River are a globally unique ecosystem essential for the regional sustainable economic development.These lakes have recently been under pressure from both...Shallow lakes of the middle-lower reaches of Changjiang(Yangtze)River are a globally unique ecosystem essential for the regional sustainable economic development.These lakes have recently been under pressure from both human activities and climate change,underscoring the need for research on their ecological health and drivers.However,most previous studies focused on large lakes(i.e.,over 500 km^(2))and limited ecological elements,such as nutrient levels.Caizi Lake,a relatively small(approximately 226 km^(2)),a Changjiang River-isolated shallow lake,was chosen as a case of study.We assessed its ecological health and analyzed the driving forces using an integrated dataset from in situ observations,remote sensing,and historical data.Our findings indicate that in 2023,the mean ecological health score,reflecting from all selected elements—algal bloom area,zooplankton,macroinvertebrates,macrophytes coverage,comprehensive trophic level index,and biodiversity—was 50.4 out of the maximum of 100.Notably,the ecological health scores for macrophytes coverage(1.9),macroinvertebrates(17.2),and biodiversity(44.0)were particularly low.In 1960–2007,the ecological health was deteriorated as the macrophytes coverage was dropped from 80%to 50%.The degradation of macroinvertebrate communities and a decrease in biodiversity might be primarily due to the eutrophication-induced abnormal algal proliferation.In 2007–2023,elevated water levels might degrade the macrophytes coverage and other aspects of ecological health.Therefore,we proposed an ecological health restoration plan for Caizi Lake focusing on nutrient reduction and water level regulation on the thresholds of total nitrogen and phosphorus concentrations,an and provided a reference for the protection of Caizi Lake and other cases having similar hydromorphic background.展开更多
基金Supported by the National Key Research and Development Program of China(No.2022YFC3204100)the National Natural Science Foundation of China(Nos.42107078,42271120)the Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences(No.NIGLAS2022GS03)。
文摘Shallow lakes of the middle-lower reaches of Changjiang(Yangtze)River are a globally unique ecosystem essential for the regional sustainable economic development.These lakes have recently been under pressure from both human activities and climate change,underscoring the need for research on their ecological health and drivers.However,most previous studies focused on large lakes(i.e.,over 500 km^(2))and limited ecological elements,such as nutrient levels.Caizi Lake,a relatively small(approximately 226 km^(2)),a Changjiang River-isolated shallow lake,was chosen as a case of study.We assessed its ecological health and analyzed the driving forces using an integrated dataset from in situ observations,remote sensing,and historical data.Our findings indicate that in 2023,the mean ecological health score,reflecting from all selected elements—algal bloom area,zooplankton,macroinvertebrates,macrophytes coverage,comprehensive trophic level index,and biodiversity—was 50.4 out of the maximum of 100.Notably,the ecological health scores for macrophytes coverage(1.9),macroinvertebrates(17.2),and biodiversity(44.0)were particularly low.In 1960–2007,the ecological health was deteriorated as the macrophytes coverage was dropped from 80%to 50%.The degradation of macroinvertebrate communities and a decrease in biodiversity might be primarily due to the eutrophication-induced abnormal algal proliferation.In 2007–2023,elevated water levels might degrade the macrophytes coverage and other aspects of ecological health.Therefore,we proposed an ecological health restoration plan for Caizi Lake focusing on nutrient reduction and water level regulation on the thresholds of total nitrogen and phosphorus concentrations,an and provided a reference for the protection of Caizi Lake and other cases having similar hydromorphic background.
