三江源区祁连圆柏群落物种多样性沿海拔梯度的变化格局

Species Diversity of Juniperus przewalskii Community in Three River Headwater along Altitude Gradient

采取典型样地法,以三江源保护分区的麦秀林场、中铁林场的祁连圆柏天然群落为研究对象,调查群落内物种盖度、多度、频度等,分析了物种组成和α多样性、β多样性对海拔梯度的响应,旨在对当地物种多样性保护及经济作物的培育提供参考,同时为青海省柏树生态系统服务功能评价提供理论依据。结果表明:(1)样地内共调查到植物72种,隶属27科58属,其中裸子植物1科1属1种,双子叶植物21科48属61种,单子叶植物5科9属10种,并以菊科在群落里种类最多。(2)植物物种丰富度表现为:草本层>灌木层>乔木层,乔木层以祁连圆柏占绝对优势,灌、草层的物种丰富度在海拔梯度上则呈明显的“偏锋”格局,且均在海拔3150 m处达到最大值。(3)随着海拔的上升,灌木层及草本层α多样性呈“波动”形变化趋势,均在海拔3550 m处达到最低值。(4)灌木层的Cody指数在海拔2950~3150 m段达到峰值,草本层在海拔3150~3350 m处达到峰值;Sorenson指数灌木层在海拔2950~3150 m和3350~3550 m处均出现峰值,草本层在海拔2950~3150 m处出现峰值。研究认为,三江源保护区在生态修复过程中,应在低海拔地区加强管护,控制人为干扰的强度,并加大当地经济植物资源培育与利用,以增加农牧民的收益。

In order to provide reference for the protection of local species diversity and cultivation of economic crops as well as provide a basis for the ecosystem service function assessment of Juniperus,we investigated the coverage,abundance,frequency,etc and analyzed the responses of species composition,αdiversity andβdiversity to elevation gradient in the communities of Juniperus przewalskii natural forest in Maxiu forest centre and Zhongtie forest centre in Three River Headwater based on the field investigation.The results indicated that:(1)a total of 72 species were investigated in the sample plot,belonging to 27 families and 58 genera.Among them,1 species of gymnosperms belong to 1 family and 1 genus,61 species of dicotyledonous belong to 21 families and 48 genera,10 species of monocotyledonous belong to 5 families and 9 genera.For Juniperus przewalskii forest,Compositae are dominant.(2)The species richness of vegetation layer was as follows:herb layer>shrub layer>arbor layer.The arbor layer was dominated by J.przewalskii,while the species richness of shrub and herb layer showed an obvious“lateral pattern”on the elevation gradient,both reaching the maximum value at 3150 m.(3)With the rise of altitude,shrub layer and herb layerαdiversity showed a“wave”-shaped change trend,reaching the lowest value at 3550 m.(4)The Cody index of shrub layer reached its peak at 2950-3150 m,and that of herb layer reached its peak at 3150-3350 m.The Sorenson index of shrub layer peaks at 2950-3150 m and 3350-3550 m,while herb layer peaks at 2950-3150 m.Therefore,in the process of ecological restoration,the degree of human disturbance should be controlled at low altitudes and the cultivation and utilization of local economic plants should be increased for enhancing the income of farmers and herders.