Abstract: 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 \[perennial waterlogged area (Ⅰ), seasonal waterlogged area (Ⅱ), and stage waterlogged area (Ⅲ)\] 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.

Key words: Beckmannia syzigachne, Kobresia tibetica, small-scale point pattern, interspecific association, alpine peatland