鄱阳湖水生植被30年演变及其驱动因素分析

基于1983和2013年两次鄱阳湖综合科学考察植被调查结果发现，30年来鄱阳湖水生植被呈退行性演变。主要体现在：（1）水生植被面积大幅缩减，沉水植被面积减少37.7%，菱等敏感物种面积减幅为87.6%；（2）群落结构简单化，组成物种由5～8种下降至3～5种，苦草替代竹叶眼子菜成为优势物种；（3）生物多样性降低，单位面积生物量减少。驱动此演变的主要因素包括：（1）长期持续的低枯湖水位压缩了水生植物的生存空间；（2）湖水氮磷浓度增加恶化沉水植被的生境；（3）洪水灾害干扰沉水植物正常生长发育，诱发沉水植被演替；（4）过度的人类活动直接或间接损害沉水植被。为了遏制退行性演变趋势、保护湿地植被生态系统的健康，建议采取有力的湖泊管理措施，将人类活动控制在湿地生态系统可承受范围之内。

Analysis of Evolution Process and Driving Factors for Aquatic Vegetations of Poyang Lake in 30 Years

Based on scientific exploration in 1983 and 2013, the data of wetland vegetation were collected and analyzed. In the last 30 years, aquatic vegetations of Poyang Lake were in a slowly degenerative process, the conclusion shown that: (1) compared with the 1983, the area of submersed aquatic vegetations in 2013 were decreased significantly, submersed aquatic vegetations were decreased by 37.72%, water caltrop was decreased by 87.6%; (2) community structure was simplified, community species were decreased from 5-8 to 3-5, dominant species were changed from Potamogeton wrightii Morong to Vallisneria sp.; (3)the biodiversity and biomass in unit area was decreased. The main reasons for the degeneration were following as: (1) long duration of low water lever reduced the living space for aquatic vegetations; (2) habitat of submerged aquatic vegetation were deteriorated by increasing concentration of nitrogen and phosphorus; (3) growing of submerged aquatic vegetation were disturbed by flood, flood might as a turning point for succession of submerged aquatic vegetation; (4) submerged aquatic vegetation were influenced by human reactivity. To contain the degenerative evolution and maintain the health of wetland vegetation ecosystem, human activities should be controlled, making Poyang Lake to be rehabilitated.