Wu Hui Feng, Song Li Juan, Du Feng, Hao Wen Fang
College of Life Science, Northwest A&F University, Yangling 712100, Shaanxi, China.
Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, Shaanxi, China.
Ying Yong Sheng Tai Xue Bao. 2017 Nov;28(11):3494-3504. doi: 10.13287/j.1001-9332.201711.005.
Focused on different rehabilitation ages grassland in Wuqi County in loess hilly region, the present study aimed to explore niche characteristics of populations and their influence factors. The results showed that the dominant species were Artemisia sacrorum, A. leucophylla, A. scoparia, Lespedeza daurica and Poa sphondylodes, and the dominant species varied along with the rehabilitation age. The niche breadth of dominant populations increased with increasing rehabilitation age from 5 to 10 years, indicating enhanced adaptability to the environment. The niche breadth indices of the populations decreased from 10 to 20 years, and then increased from 20 to 25 years. After 25 years, the niche breadth of the grassland narrowed gradually, indicating weakened adaptability. The niche breadth indices of most populations peaked at 10 and 25 years, respectively. There was no li-near relationship between synthetic dominance index and niche breadth in different grass communities. With the increasing rehabilitation age, the niche overlap indices were highest at 15 years with a single hump pattern, indicating that the interspecific competition increased to the highest at 15 years and then decreased. It was shown that attitude, soil water content (SWC) and soil organic matter content (SOM) were the main factors affecting the niche breadth, while soil total nitrogen content (STN), attitude and SWC were the main factors affecting the niche overlap. There was no linear relationship between niche breadth and niche overlap of tested species in different rehabilitation ages due to resource spatial heterogeneity and growth stages of grass species. These findings indicated that with the increasing rehabilitation age, the population adaptability to the environment are generally enhanced and the resource competition among populations increases and then decreases. It was concluded that attitude, SWC and STN were the key environmental factors that affect population adaptability and interspecific relationship in natural grassland of loess hilly region.
针对黄土丘陵区吴起县不同恢复年限的草地，本研究旨在探讨种群生态位特征及其影响因素。结果表明，优势种为铁杆蒿、白叶蒿、茵陈蒿、达乌里胡枝子和硬质早熟禾，优势种随恢复年限而变化。优势种群的生态位宽度在恢复年限从5年增加到10年时增大，表明对环境的适应性增强。种群的生态位宽度指数在10年到20年时减小，然后在20年到25年时增大。25年后，草地的生态位宽度逐渐变窄，表明适应性减弱。大多数种群的生态位宽度指数分别在10年和25年达到峰值。不同草地群落的综合优势度指数与生态位宽度之间不存在线性关系。随着恢复年限的增加，生态位重叠指数在15年时最高，呈单峰模式，表明种间竞争在15年时增加到最高水平，然后下降。结果表明，坡向、土壤含水量（SWC）和土壤有机质含量（SOM）是影响生态位宽度的主要因素，而土壤全氮含量（STN）、坡向和SWC是影响生态位重叠的主要因素。由于资源空间异质性和草本植物生长阶段的影响，不同恢复年限下受试物种的生态位宽度与生态位重叠之间不存在线性关系。这些结果表明，随着恢复年限的增加，种群对环境的适应性总体增强，种群间的资源竞争先增加后减少。研究得出结论，坡向、SWC和STN是影响黄土丘陵区天然草地种群适应性和种间关系的关键环境因素。
