Liu Yaxuan, Zeng Yong, Wang Peng, He Jia, Li Pingping, Liang Yuejia
College of Geographic Science and Tourism, Xinjiang Normal University, Urumqi, China.
Xinjiang Laboratory of Lake Environment and Resources in Arid Zone, Urumqi, China.
Front Plant Sci. 2024 Jul 3;15:1276489. doi: 10.3389/fpls.2024.1276489. eCollection 2024.
Population-level competition and spatial patterns may explain the role of competitive exclusion in communities, which is important for vegetation restoration and biodiversity conservation.
We analyzed the competitive intensity, spatial patterns, and renewal of Oliv. forests in the Tarim River Basin using the Hegyi competition index and spatial point pattern analysis in a completely random model with different habitats and different forest ages.
The greatest competitive distance for was 10 m, and the intensity of competition steadily decreased as the diameter increased. The intensity of intraspecific and interspecific competition in young, mature, and old forests was as follows: riverside habitat > transitional habitat > desert margin habitat. The Simpson index values for the three habitats decreased as follows: transitional > riverside > desert margin, and the Shannon-Wiener index and Pielou index values decreased as follows: riverside > transitional > desert margin. In the riverside habitat, the young forest experienced the greatest competitive intensity, the mature forest in the transitional habitat was the largest, and the forest in the desert margin habitat was the oldest. Competitive intensity was greatest in the young riverside forest, mature forest in the transitional habitat, and old forest in the desert margin. Riverside experienced strong competition from . Competitive exclusion caused to disappear from the transitional and desert margin habitats. Young, mature, and old forests were randomly distributed along the riverside and in the transitional habitat, while mature and old forests were randomly distributed in the desert margin. , , and were mainly randomly distributed, and and were clustered at small scales. In the riverside habitat, young, mature, and old had no spatial correlation, and there was a significant negative correlation at small scales in the transitional habitat. The density of seedlings in the riverside habitat was greater than that in the transitional habitat, and greater competitive pressures on tree seedlings caused a lower renewal density.
When planting forests, spacing greater than 10 m can effectively reduce stand competition and thus promote seedling regeneration.
种群水平的竞争和空间格局可以解释竞争排斥在群落中的作用，这对植被恢复和生物多样性保护很重要。
我们使用赫吉竞争指数和空间点格局分析，在完全随机模型中，对塔里木河流域不同生境和不同林龄的胡杨林的竞争强度、空间格局和更新情况进行了分析。
胡杨的最大竞争距离为10米，竞争强度随着直径增加而稳步下降。幼龄、成熟和老龄胡杨林中种内和种间竞争强度如下：河岸生境＞过渡生境＞沙漠边缘生境。三个生境的辛普森指数值下降顺序为：过渡生境＞河岸生境＞沙漠边缘生境，香农-维纳指数和皮洛指数值下降顺序为：河岸生境＞过渡生境＞沙漠边缘生境。在河岸生境中，幼龄胡杨林竞争强度最大，过渡生境中的成熟林面积最大，沙漠边缘生境中的林龄最老。竞争强度在河岸幼龄胡杨林、过渡生境中的成熟胡杨林和沙漠边缘老龄林中最大。河岸胡杨受到来自[未提及具体物种]的强烈竞争。竞争排斥导致[未提及具体物种]在过渡生境和沙漠边缘生境中消失。幼龄、成熟和老龄胡杨林在河岸和过渡生境中呈随机分布，而成熟和老龄胡杨林在沙漠边缘呈随机分布。[未提及具体物种]主要呈随机分布，[未提及具体物种]在小尺度上呈聚集分布。在河岸生境中，幼龄、成熟和老龄胡杨没有空间相关性，在过渡生境中小尺度上存在显著负相关。河岸生境中胡杨幼苗密度大于过渡生境，对胡杨树苗更大的竞争压力导致更新密度较低。
种植胡杨林时，间距大于10米可有效降低林分竞争，从而促进幼苗更新。
