Abstract:

Aims Steppe dominated by Stipa grandis and Leymus chinensis is the zonal vegetation in the temperate steppe region of China and eastern Eurasia. It has been heavily disturbed by overgrazing in China. Our objective was to investigate the spatial pattern of L. chinensis in a degraded community of steppe during restorative succession.
Methods We studied three fenced plots of degraded steppe in the Xilin Gole League, Inner Mongolia, China, which had been monitored by the Inner Mongolia Grassland Ecosystem Research Station, Chinese Academy of Sciences. We applied a new method of photography to measure the population pattern of L. chinensis, analyzing the point pattern, the area of “hole”, population territory area and territory density in different restorative succession stages.
Important findings During the process of restorative succession, the L. chinensis population increased, decreased and became stable. The population originally increased because colonization exceeded self-thinning. The decrease resulted primarily from interspecific competition and secondarily from intraspecific competition. The change of the hole was the result of the increase and decrease of L. chinensis, which led to the change of the pattern type. The distribution of Leymus chinensis was clumped at 0-4.85 m and random at 4.85-10 m in the sample plot fenced-off since 1983. It was clumped at 0-3.01 m, random at 3.01-3.37 m and regular at 3.37-10 m in the sample plot fenced-off since 1996. But it was clumped at 0-10 m in the seriously degraded community.

Key words: Leymus chinensis, restoring succession, population pattern, photography orientation method, hole of population, point pattern analysis, population territory area, territory density