高寒泥炭沼泽菵草与藏嵩草种群空间分布格局及其关联性

Spatial pattern and interspecific association of Beckmannia syzigachne and Kobresia tibetica in an alpine peatland

探讨高寒泥炭沼泽植物的空间分布格局及其对环境响应,对于认识高寒泥炭沼泽的物质循环机制具有重要意义。在青藏高原东缘的狼渡滩泥炭沼泽湿地,设置常年积水区(Ⅰ)、季节性积水区(Ⅱ)、阶段性积水区(Ⅲ)3个水位样地,采用小尺度点格局分析方法,分析了不同水位下菵草和藏嵩草种群的空间分布格局及种间关联关系。结果表明:(1)随着地表积水深度的下降,湿地群落优势种由菵草演变为藏嵩草,土壤有机碳含量逐渐减少,而土壤全氮和土壤全磷呈现增加趋势;(2)从常年积水区到阶段性积水区,菵草种群空间格局由聚集分布转变为随机分布;藏嵩草种群空间格局由随机分布转变为聚集分布;(3)在常年积水区和阶段性积水区菵草和藏嵩草的空间关联性表现为负相关和不相关,在季节性积水区表现为负相关。高寒泥炭沼泽淹水条件、微地貌、土壤养分空间异质性影响了种群的空间分布格局和种间关联性,反映了高寒泥炭沼泽植物的生态适应性策略。

Studying the spatial distribution and environmental response of plants in alpine peatlands is of great significance for understanding the material cycling mechanism of alpine peatlands.Three plots with different water levels perennialwaterloggedarea(Ⅰ),seasonalwaterloggedarea(Ⅱ),andstagewaterloggedarea(Ⅲ)were set up in a peatland wetland in Langdutan on the eastern edge of the Tibetan Plateau.The spatial distribution pattern and interspecific associations between the populations of Beckmannia syzigachne and Kobresia tibetica in different water levels were analyzed using the small-scale point pattern analysis method.The results showed that:(1)with the decreases of surface water depth,the dominant species shifted from B.syzigachne to K.tibetica,soil organic carbon content gradually decreased,soil total nitrogen and total phosphorus contents showed an increasing trend;(2)with shifting from perennial waterlogged area to stage waterlogged area,the spatial pattern of B.syzigachne populations changed from aggregated to random distribution,and that of K.tibetica populations shifted from random to aggregated distribution;(3)the spatial correlations of B.syzigachne and K.tibetica were negatively correlated and non-correlated in perennial waterlogged area and stage waterlogged area,and negatively correlated in seasonal waterlogged areas.Spatial heterogeneity of inundation conditions,micro-geomorphology,and soil nutrient heterogeneity in alpine peatlands affect the spatial distribution pattern of populations and interspecific correlations,reflecting ecological adaptation strategies of plants in alpine peatlands.