Guo Yan, Yang Shao, Shen Ya Fei, Xiao Wen Fa, Cheng Rui Mei
State Forestry Administration Key Laboratory of Forest, Ecology and Environment, Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, China.
Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing 210037, China.
Ying Yong Sheng Tai Xue Bao. 2018 Nov;29(11):3559-3568. doi: 10.13287/j.1001-9332.201811.006.
To understand the usages of available resource by dominant plants, their niches and the mechanisms of inter-specific competition and co-existence in the water level fluctuation zone, we studied the spatial distributions and niche characteristics of existing dominant herbaceous species at a typical water-level-fluctuation site of the Three Gorges Reservoir Area, Zigui. The results showed that there were 39 herb species in total, which belonged to 18 families and 32 genera. Gramineae, Compositae, Polygonaceae and Euphorbiaceae were the dominant families. Cynodon dactylon, Setaria viridis, Bidentis tripartitae and Digitaria chrysoblephara were the dominant species, with high importance value and niche breadth. In addition, at 145-155 m, 155-165 m and 165-175 m altitude section, the three major species, expressing the highest ecological niche breadth, which were in order of C. dactylon ＞ Polygonum lapathifolium ＞ S. viridis, S. viridis ＞ D. chrysoblephara ＞ C. dactylon, and S. viridis ＞ B. tripartitae ＞ P. orientale, respectively. The niche overlap of the species between the different altitudes zone was relatively high. The species which had a broad niche could co-exist with those occupying narrow niche. The niche overlap could not be determined by niche breadth lonely. Furthermore, after seven times of water level fluctuations, most of the species were annual herbs, and the degree of niche differentiation was low in the area. Due to scarce resources and unstable habitats, the inter-specific competition was strong, and the vegetation was at the primary successional stage.
为了解三峡库区典型消落带优势植物对资源的利用方式、生态位及其种间竞争与共存机制，我们研究了三峡库区秭归某典型消落带现有优势草本植物的空间分布和生态位特征。结果表明，该区域共有39种草本植物，分属18科32属。禾本科、菊科、蓼科和大戟科为优势科。狗牙根、绿狗尾草、三叶鬼针草和金色狗尾草为优势种，重要值和生态位宽度较高。此外，在海拔145 - 155m、155 - 165m和165 - 175m区段，生态位宽度最大的3个优势种依次为狗牙根＞酸模叶蓼＞绿狗尾草、绿狗尾草＞金色狗尾草＞狗牙根、绿狗尾草＞三叶鬼针草＞东方蓼。不同海拔区段间物种的生态位重叠较高。生态位宽的物种与生态位窄的物种能够共存，生态位重叠不能仅由生态位宽度决定。此外，经过7次水位涨落，该区域多数物种为一年生草本植物，生态位分化程度较低。由于资源匮乏和生境不稳定，种间竞争强烈，植被处于初级演替阶段。
