| Popis: |
Ecosystems on earth have endured rapid changes over the last decades, but freshwater wetlands have disproportionally suffered biodiversity loss. Understanding the drivers of the decline of wetland ecosystems is the prerequisites for effective management scheme. However, a lack of long-term data on biological indicators like benthic macroinvertebrates have limited our understanding. Under the critical time window of the recent Anthropocene, China's longest in-situ aquatic biomonitoring data were combined with satellite imaging to construct profiles of some essential biodiversity variables of the Dongting Lake, a large Ramsar wetland in the Yangtze River basin. The results showed that the integrity of macroinvertebrate community systematically declined in the last three decades, accompanied by the stresses of lake eutrophication, climate warming and weakening of the connectivity between the Yangtze River and the lake. Unlike previously speculated attribution, the establishment of the Three Gorges Dam was found to only have a limited impact on the biodiversity loss of Dongting Lake. Changes in human land-use intensity in the surrounding terrestrial ecosystem, by increasing nutrient loading, were found to be the main mechanism resulting in the decline of macroinvertebrates. Biodiversity changes were most influenced by land-use within 1.5 km from the water body. The results highlight that to attenuate such a major local land-use effect, establishing a protected buffer area surrounding wetland ecosystems will help preserve biodiversity in the future. |
