游牧与定居放牧下山地草甸草地植物群落特征分析

Analysis on the Characteristics of Plant Communities in Mountain Meadow Grassland under Nomadic and Settled Grazing

【目的】研究游牧与定居放牧2种方式对天山北坡中段山地草甸草地植物群落数量特征及多样性的影响,为该区域冬季牧场合理利用提供理论依据。【方法】以天山北坡中段昌吉市阿什里哈萨克民族乡的冬季牧场为对象,在游牧与定居放牧2种处理下分别设计轻度放牧、重度放牧2个放牧强度,无放牧区(围栏打草场)作为对照,采用野外实地调查取样的方法,测定分析草地植物群落种类组成、植物重要值、地上现存量及植物多样性指数。【结果】随着放牧强度的增加,植物种类数量变化表现定居>游牧,植物群落种类组成发生了明显改变,禾本科和豆科等植物重要值下降,群落优势种逐步被杂类草及醉马草等取代;植物高度、盖度、密度和地上现存量变化表现定居>游牧,植物盖度和地上现存量在游牧与定居放牧区存在显著差异(P<0.05),2个指标差异性均在定居显示最高;Margalef丰富度指数、Pielou均匀度指数、Shannon-Wiener多样性指数和Simpson生态优势度指数变化表现为定居>游牧,但两者差异不显著(P>0.05)。【结论】游牧和定居放牧影响天山北坡中段山地草甸冬季牧场植物群落基本特征。与定居放牧区相比,游牧区植物高度、盖度、密度和地上现存量随着放牧强度的递增逐步降低降幅分别为23.45%、7.43%、9.42%和13.57%;植物高度、密度、盖度和地上现存量均在游牧区处于较低水平,α多样性指数均在游牧区达到最低值。定居轻度放牧下植物种类数量最多,植物多样性和生态优势度维持在较高水平。

【Objective】The winter pasture of the mountain meadow grassland in the middle section of the northern slope of the Tianshan Mountains is used as the basic pasture for herders to graze.There are two grazing methods:nomadic and settled.To study the effects of nomadic and settled grazing on the quantitative characteristics and diversity of plant communities in mountain meadows and grasslands,and provide a theoretical basis for the rational use of winter pastures in the region.【Method】Taking the winter pasture in Ashri Kazak Nationality Township,Changji City,the middle section of the Tianshan Mountains as the object,two grazing intensities of light grazing and heavy grazing were designed under the two treatments of nomadic and settled grazing.No grazing areas(fenced pasture)was used as contrast.Using the method of field survey and sampling,the species composition of grassland plant community,plant importance value,above-ground biomass of plants and plant diversity index are measured and analyzed.【Result】With the increase of grazing intensity,the number of plant species changes as settled>nomadic,the composition of plant communities has changed significantly,the important values of grasses and legumes have declined,and the dominant species of the community have gradually been replaced by weeds and Achnatherum inebrians;Changes in plant height,coverage,density,and above-ground biomass of plants are represented by settled>nomadic.There are significant differences in plant coverage and above-ground stock between nomadic and settled grazing areas(P<0.05),and the difference between the two indicators is highest in settled;The Margalef index,Pielou index,Shannon-Wiener index,and Simpson index showed settled>nomadic,but the difference between the two was not significant(P>0.05).【Conclusion】Nomadic and settled grazing affect the basic characteristics of plant communities in winter pastures of mountain meadows in the middle of the northern slope of Tianshan Mountains.Compared with the settled grazing area,the plant height,coverage,density and above-ground biomass of plants of the nomadic area gradually decreased with the increase of grazing intensity by 23.45%,7.43%,9.42%and 13.57%.The plant height,density,and coverage are at a low level in the nomadic areas,and theαdiversity index reaches the lowest value in the nomadic.There are the largest number of plant species under settled light grazing,and the plant diversity and ecological dominance are maintained at a high level.