米氏冰草种群在恢复演替进程中的点格局分析

Point Pattern Analysis of Agropyron michnoi in Restorative Succession of Steppe Ecosystem

植物种群空间格局是植物生态学研究的基本内容之一。过度放牧引起典型草原生态系统发生退化,而探讨典型草原退化群落在恢复演替过程中种群空间格局具有重要意义。米氏冰草为典型草原群落主要优势种之一,在恢复演替过程中,群落会经历冷蒿+米氏冰草群落阶段和米氏冰草群落阶段。选择米氏冰草种群作为研究对象,应用O-Ring函数结合不同零模型分析米氏冰草种群在恢复演替过程中的格局变化。研究结果表明:在严重退化群落中,米氏冰草种群在精细尺度上存在高密度的小聚块,种群格局表现为大聚块中出现高密度的小聚块;而在恢复8年群落和恢复21年群落中,大聚块中并未出现高密度的小聚块。这样的格局特征说明米氏冰草种群在恢复演替过程中经历了精细尺度上高密度小聚块消失的过程,是退化群落在恢复过程中种群个体间正相互作用向竞争转化所致。

The analysis of spatial patterns within plant populations is a key element in the field of plant ecology.Degradation of steppe ecosystems,a serious issue often triggered by excessive grazing,necessitates a detailed study of population spatial patterns during the rehabilitation of these degraded communities.Agropyron michnoi is one of the dominant species in typical steppe communities.During the process of restoration succession,the community will go through stages of both Artemisia frigida+Agropyron michnoi and Agropyron michnoi communities.Our study employed the O-Ring function and multiple null models to dissect the spatial patterns of Agropyron michnoi populations.The spatial pattern analysis of Agropyron michnoi demonstrated that within a degraded community,there were discernible centers of large clusters characterized by the presence of high-density small clusters.However,in the 8-and 21-year restoration communities,there were no high-density small clusters.These results suggest a transformative phase in the spatial patterns of Agropyron michnoi during the restoration process,characterized by the disappearance of high-density small clusters at a fine scale.This shift could be attributed to the transition from cooperative interactions to competitive dynamics among individual plants within the population as the restoration process progresses.