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| 三峡工程运行前后洞庭湖洲滩植被淹没时间变化对其分布格局的影响 |
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陈前1, 邹业爱1, 李峰1, 田恬2, 刘派1, 张雨河1, 田茂军3, 肖妮娜3
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1.中国科学院亚热带农业生态研究所;2.湖南农业大学;3.湖南省自然资源事务中心
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| 摘要: |
| 2003年三峡工程运行以来，洞庭湖湿地的水文情势发生了显著变化，进而影响了湿地植被的分布格局。然而，有关水文情势与植被分布格局之间的关系比较复杂，相关机制仍不清晰。本研究通过遥感解译和野外调查等方法分析了1995—2022年洞庭湖湿地植被格局时空演变，并结合水文数据，探讨了三峡工程运行前后洲滩植被淹没时间变化对其分布格局的影响及驱动机理。结果表明：1)东、西、南洞庭湖水位年际变化趋势总体一致。三峡工程运行后导致洞庭湖年均水位持续下降，平均下降幅度超过0.3 m，年内最高水位下降超过0.6 m，西、南洞庭湖高水位持续时间缩短，并逐渐向低水位转移；2)1995—2022年，洞庭湖湿地植被面积不断增加，湿地植被整体呈正向演替趋势，具体表现为芦苇群落侵占苔草群落，苔草群落侵占光滩；3)三峡工程运行前后光滩→苔草、苔草→芦苇两个正向演替区域的淹没时间极显著下降(p < 0.01)，而苔草→光滩与芦苇→苔草这两个逆向演替区域淹没时间变化呈增加趋势，但变化不显著(p > 0.05)，这表明淹没时间下降可能是洞庭湖湿地植被正向演替的关键驱动因素之一。 |
| 关键词: 湿地植被演替 三峡工程 时空演变 水文变化 遥感监测 水文驱动机制 水文-植被关系 |
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| 基金项目:国家重点研发计划课题、洞庭湖区生态环境遥感监测湖南省重点实验室开放课题基金资助 、国家自然科学基金面上项目、湖南省杰出青年基金项目、湖南省科技创新平台计划、湖南省自然资源科技计划项目 |
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| The Impact of Inundation Duration Changes on the Distribution Pattern of Sandbar Vegetation in Dongting Lake Before and After the Operation of the Three Gorges Project |
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Chenqian1, zouyeai1, lifeng1, tiantian2, liupai1, zhangyuhe1, tianmaojun3, xiaonina3
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1.Institute of Subtropical Agriculture,Chinese Academy of Sciences;2.Hunan Agricultural University;3.Hunan Provincial Center for Natural Resources Affairs
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| Abstract: |
| Since the operation of the Three Gorges Project in 2003, the hydrological regime of the Dongting Lake wetlands has undergone significant changes, subsequently affecting the distribution pattern of wetland vegetation. However, the relationship between the hydrological regime and vegetation distribution is complex, and the underlying mechanisms remain unclear. This study analyzed the spatial and temporal evolution of the Dongting Lake wetland vegetation pattern from 1995 to 2022 through remote sensing interpretation and field investigations, combined with hydrological data to explore the changes in inundation duration of sandbar vegetation before and after the Three Gorges Project and the driving mechanisms behind these changes. The results showed that: 1) The interannual variation trends of water levels in East, West, and South Dongting Lake were generally consistent. The operation of the Three Gorges Project led to a continuous decline in the annual average water level of Dongting Lake, with an average decrease of over 0.3 m and a maximum annual water level decrease exceeding 0.6 m. The duration of high water levels in West and South Dongting Lake shortened, shifting gradually toward lower water levels; 2) From 1995 to 2022, the overall trend of vegetation succession in the Dongting Lake wetlands has been positive, with a continuous expansion in wetland vegetation area, specifically characterized by the encroachment of Phragmites australis communities on Carex brevicuspis, and C. brevicuspis communities on bare mudflats. 3) Changes in inundation duration before and after the operation of the Three Gorges Dam were significant in areas undergoing positive succession(p < 0.01), from bare mudflats to C. brevicuspis and from C. brevicuspis to P. australis, whereas the changes were not significant in areas experiencing regressive succession(p > 0.05), from C. brevicuspis to bare mudflats and from P. australis to C. brevicuspis. This suggests that reductions in inundation duration are a key driving factor promoting the positive succession of wetland vegetation in Dongting Lake. |
| Key words: Wetland Vegetation Succession Three Gorges Reservoir Hydrological Changes in Dongting Lake Remote Sensing Monitoring Hydrological Driving Mechanism Hydrology-Vegetation Relationship |
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