古尔班通古特沙漠南缘心叶驼绒藜种群更新的空间格局

Spatial Pattern of Population Recruitment of C. ewersmanniana in South of Gurbantunggut Desert

心叶驼绒藜(C.ewersmanniana)是干旱区优质牧草和防风固沙植被的主要物种。在古尔班通古特沙漠南缘选择两个200 m×200 m具代表性样地,采用Ripley’sK(d)函数分析了心叶驼绒藜种群更新空间特征以及与群落梭梭(Haloxylon ammodendron)、琵琶柴(Reaumuria soongorica)、新疆绢蒿(Seriphidium kaschgaricum)等三种主要灌木物种间作用关系。发现两个样点心叶驼绒藜大株(繁殖株)的空间分布对后代以及整个种群的空间分布影响极大,两个样点心叶驼绒藜大株、中株均与幼株间呈不同尺度的正关联,全部植株以及幼株都与新疆绢蒿呈正关联,与梭梭呈负关联,与琵琶柴关联性在两个样点结果相反。分析认,为心叶驼绒藜种群更新对成株依赖性极强,空间扩展能力很低。在0—35 m范围内种群更新的空间自相关性明显。四种灌木空间分布关系除受各自生态位决定外,主要受水等环境因素作用。最后对心叶驼绒藜等生态恢复方法提出建议。

C.ewersmanniana is a kind of high-quality herbage in arid region,and the construction species of wind-sheltering and sand-fixing vegetation.In this paper,two representative samples of 200m 200m were set in south of Gurbantunggut desert.Ripley＇s K（d） function was used to determine the spatial pattern of population regeneration of C.ewersmanniana and its relationship with the three main shrub populations（H.ammodendron,R.soongorica,S.kaschgaricum）.In both samples,the spatial pattern of population recruitment was influenced greatly by the distribution of adult C.ewersmanniana.Adult and middle-aged C.ewersmanniana exhibited positive correlation with young C.ewersmanniana.C.ewersmanniana had positive correlation with S.kaschgaricum,but had negative correlation with H.ammodendron.Its correlation with R.soongorica was opposite in the two samples.We concluded that the population recruitment of C.ewersmanniana depended severely on adult plants.The spatial autocorrelation of its population recruitment was obvious within 30 m.This spatial autocorrelation was affected greatly by the environment and had weak ability to expand.In addition,the growth of four shrubs was determined by niche of each species,and was influenced greatly by water and other environmental factors.In the end,suggestion for ecological restoration of shrubs including C.ewersmanniana was raised.