三峡水库156 m蓄水后消落带新生湿地植物群落

三峡水库156 m蓄水后,已形成大面积消落带湿地.2008年7-9月对地处三峡水库腹地的开县澎溪河左岸一级支流白夹溪消落带新生湿地植物进行了调查.结果表明:该区域共有高等湿地植物33种,优势种有双穗雀稗、宽叶香蒲、萤蔺、藨草、长鬃蓼.新生湿地植物群落划分为8个群丛.沿河流侧向空间梯度,湿地植物群落的带状分布明显,分为河漫滩1年生草本植物带、苍耳带、双穗雀稗带3个植物带.从河岸到海拔156 m处,植物地上生物量呈现出先增加后减少再增加的趋势.消落带区域在水位下降后,土壤含水率的增加为湿地植物生长提供了良好生境.双穗雀稗成为156 m蓄水后白夹溪河岸二级阶地地势低洼处的优势植物;苍耳在河岸一级阶地和二级阶地之间的坡地上广泛分布.三峡水库蓄水后消落带土壤含水率的变化、微地貌格局对消落带新生湿地群落空间格局具有明显影响.

Abstract：

After flooding to 156 m height, a wide area of wetlands emerged in the water-level fluctuation zone of Three Gorges Reservoir. From July to September 2008, an investigation was made on the plant communities beside Baijia stream, the first order tributary of Pengxi River in Kaixian County of Chongqing. There were 33 species of wetland vascular plants, among which, Paspalum paspaloides, Typha latifolia, Scirpus juncoides, S. triqueter, Polygonum longisetum were the dominant. The plant communities in study area were divided into eight associations. An obvious zonal distribution was observed at the lateral side of Baijia stream from riparian to 156 m altitude. There were three plant zones, i. e. , floodplain annual herb zone, X. sibiricum zone, and P. paspaloides zone. With increasing elevation, the aboveground biomass showed a single-peak pattern. During the period with lower water level, the increase of soil water content acceler-ated the growth of wetland plants. P. paspaloides was most dominant in the low-lying area of sec-ond terraces of Baijia stream, and X. sibiricum widely distributed on the sloping field between the first and second terraces of the stream. The variations of soil water content and micro-geomorphic pattern significantly affected the distribution of plant communities in water-level fluctuation zone.

Plant communities in newly created wetlands in water-level fluctuation zone of Three Gorges Reservoir after flooding to 156 m height

After flooding to 156 m height, a wide area of wetlands emerged in the water-level fluctuation zone of Three Gorges Reservoir. From July to September 2008, an investigation was made on the plant communities beside Baijia stream, the first order tributary of Pengxi River in Kaixian County of Chongqing. There were 33 species of wetland vascular plants, among which, Paspalum paspaloides, Typha latifolia, Scirpus juncoides, S. triqueter, Polygonum longisetum were the dominant. The plant communities in study area were divided into eight associations. An obvious zonal distribution was observed at the lateral side of Baijia stream from riparian to 156 m altitude. There were three plant zones, i. e. , floodplain annual herb zone, X. sibiricum zone, and P. paspaloides zone. With increasing elevation, the aboveground biomass showed a single-peak pattern. During the period with lower water level, the increase of soil water content acceler-ated the growth of wetland plants. P. paspaloides was most dominant in the low-lying area of sec-ond terraces of Baijia stream, and X. sibiricum widely distributed on the sloping field between the first and second terraces of the stream. The variations of soil water content and micro-geomorphic pattern significantly affected the distribution of plant communities in water-level fluctuation zone.