Abstract: 【Objective】 To study the effects of different grazing intensities on plant community quantitative characteristics and diversity of Seriphidium transiliense desert grassland.【Method】 The S. transiliense desert degraded grassland in the northern slope of Tianshan Mountain was taken as the research object, and three kinds of grazing intensities, including CK, LG and MG were set. The height, coverage, density, and biomass of plant communities were measured in fields, and the diversity index was calculated.【Result】 Under three grazing intensities, the important value of Seriphidium transiliense increased first and then decreased and the proportion of annual plants was higher. With the increase of grazing intensity, the height, coverage, density, biomass and important value decreased, while the density, biomass and important values of Salsola collina and Chenopodium album which livestock didn't graze increased. Margalef index, Simpson index and Shannon-Wiener index decreased from 0.45, 0.5, 0.72 to 0.25, 0.20 and 0.33, respectively, while the Pielou index had no significant difference. The diversity index of plant and important value of S. transiliense were positively correlated, and important value of annual plants were negatively correlated.【Conclusion】 It's concluded that plant communities become dwarf and sparse, species richness and diversity decreased with the increase of grazing intensity, and plant communities are dominated by annual plants.

Key words: Seriphidium transiliense; desert degraded grassland; autumn pasture; community characteristics; plant diversity

摘要： 【目的】研究不同放牧强度对伊犁绢蒿荒漠草地植物群落数量特征及多样性的影响。【方法】以新疆天山北坡伊犁绢蒿荒漠退化草地为研究对象,选择对照、轻度放牧、重度放牧3个强度,野外测定群落的高度、盖度、密度及生物量并计算多样性指数。【结果】3种放牧强度下,伊犁绢蒿的重要值呈先增加后降低的趋势,一年生植物的比例均较高;随放牧强度的增加,群落高度、盖度、密度、生物量及重要值呈下降趋势,家畜不喜食的猪毛菜和灰藜的密度、生物量和重要值逐渐增加;植物群落Margalef指数、Simpson指数和Shannon-Wiener指数分别从0.45、0.5和0.72显著降低到0.25、0.20和0.33,而Pielou指数则无显著差异;植物群落多样性指数与伊犁绢蒿重要值呈正相关,与一年生植物重要值呈负相关。【结论】随着放牧强度的增加,植物群落趋于低矮稀疏,物种丰富度和多样性降低;一年生植物在植物群落中占主要优势。

关键词: 伊犁绢蒿, 荒漠退化草地, 秋牧场, 群落特征, 植物多样性