三峡库区消落带陆生植被对首次水陆生境变化的响应

Responses of Terrestrial Plants in Hydro-Fluctuation Belt of the Three Gorges Reservoir Area to the First Time Flooding-Drying Habitat Change

基于固定监测样地,对三峡库区消落带海拔156～172m区段首次经历冬水夏陆交替变化影响前、后的植物组成、个体数量、物种盖度等群落学特征进行调查,并计算各类植物生活型在群落中的比例以及各物种的重要值,研究三峡库区消落带陆生植被对首次水陆生境变化的响应。结果表明:经历水陆交替变化前,在样地上共记录到维管植物55科147种,经历水陆交替变化后,仅剩17科32种,科数减少了69.1%,种数减少了78.2%,与此同时,样地上出现了49种新植物,约占调查当年样地植物种数的60.5%;植物生活型组成发生改变,乔木和灌木减少,草本植物增加;不同植物对环境变化的反应不同,莎草科、禾本科和菊科的草本植物表现出较强的适应能力,代表种有香附子、狗尾草、狼把草、马唐、野茼蒿和青蒿,黄荆、盐肤木、假奓苞叶马桑和铁仔这4种灌木树种的1年生实生苗及乌桕、复羽叶栾树和构树这3种乔木树种的1年生实生苗也表现出较强的适应性。

To study the response of terrestrial plants in hydro-fluctuation belt to the first time habitat flooding-drying cycle in the Three Gorges Reservoir Area, Yangtze River, we investigated community characteristics, such as plants composition, number of individuals, species coverage, when this place was flooded in winter and then exposed in summer in the elevation from 156 to 172 meters. We calculated species’ important value as well as the proportion of all plant life forms in the community. The result showed that there were 147 vascular plants species belonging to 55 families before the fluctuation cycle. However, there were only 32 species belonging to 17 families after the fluctuation cycle and the proportion of families and species were reduced by 69.1% and 78.2%, respectively. Meanwhile, the plots newly emerged 49 plant species which accounted for 60.5% in the total species. The composition of plant life forms changed, that is, trees and shrub species declined while the herbaceous increased. Different plants reacted differently to environmental changes. Cyperaceae, Gramineae, and Compositae herbs showed a strong adaptation capacity to the change. The representative species were Cyperus rotundus, Setaria viridis, Bidens tripartite, Digitaria sanguinalis, Gynura crepidioides, Artemisia apiacea, etc. One-year-old seedlings of shrub species of Vitex negundo, Rhus chinensis, Discocleidion rufescens, Coriaria nepalensis , Myrsine africana, and tree species of Sapium sebiferum, Koelreuteria bipinnata, Broussonetia papyrifera all showed strong adaptability.