拉萨半干旱河谷砂生槐灌丛不同封育时间土壤动物多样性特征

为了解半干旱河谷不同封育时间对砂生槐灌丛土壤动物群落组成及结构的影响,阐明土壤动物群落多样性及群落结构在高原灌丛植被恢复中的变化趋势,本研究对拉萨河中下游的不同封育时间砂生槐灌丛下土壤动物群落结构、垂直分布、多样性、土壤动物类群间的相关性特征进行分析。结果表明,砂生槐灌丛90份土样中共获得大中小型土壤动物491只,隶属3门9纲25类。优势种群为弹尾目、鞘翅目和蜱螨目,分别占类群总数的42.7%、15.9%和11.2%。土壤动物类群数和个体数量的垂直分布具有表聚性特征,多数土壤动物分布在0~20 cm土层,但因不同封育时间而有变化。封育10年样地0~10 cm土层土壤动物数量显著高于10~20和20~30 cm,该层土壤动物个体数占所有采集数的40.1%。随封育时间增加,植被盖度、土壤动物个体数量、类群数均呈逐渐上升趋势。土壤动物群落的多样性指数(H),均匀性指数(E),丰富度指数(D),优势度指数(I)和多群落间比较指数(DIC)基本随封育时间的增加逐渐增大,但DIC指数的最高值出现于封育10年和15年,分别为3.99和3.29,而未封育(对照)、封育4年和8年分别为0.66、0.49和0.63。不同封育时间半干旱河谷砂生槐灌丛螨类(A)/跳虫(C)值也呈现较大变异,封育4年的A/C值为2.67,高于其它封育时间,因此,A/C可作为拉萨半干旱河谷植被退化恢复演替评价的生物指示剂,这为高原生态环境状况评价提供参考依据。

Characterization of Soil Animals Changes With Vegetation Restoration Under Different Fencing Time of Sophora Moorcroftiana Shrublands in Lhasa Semi-arid Valley

In order to understand the community structure,clarify the change trend of diversity and community structure,soil animals are selected as an indicator function in highland shrub vegetation restoration of soil animals,sophora moorcroftiana shrublands in Lhasa semi-arid valley to investigate in different fencing time sophora moorcroftiana shrublands in middle and lower reaches of the Lhasa River.The characteristics of community structure,spacial distribution,diversity and correlation between soil animal types groups of soil animals were also analyzed.The results showed that,a total of 491 soil animals were obtained from Sophora moorcroftiana shrublands from 90 soil samples,which belonged to 3 phylum,9 classes and 25 groups.Collembola,Coleoptera and Acarina were dominant populations,and constituted 42.7％,15.9％ and 11.2％ of the collected soil animals,respectively.The common groups included Hymenoptera,Araneae,nematode,Isoptera,Dermaptera,Diptera,Chilopoda,Protura and blind spider mesh.The rare groups were Lepidoptera,integrated classes,Homoptera,Hua Yuan head,Thysanoptera,Isopoda,stone Microcoryphia head,hair Hymenoptera,Orthoptera,turbellaria,Gastropoda,and diplura half Hymenoptera.Soil fauna trends to gather on soil surface with most of the soil animal located in the 0 to 20cm depth of soil,which was affected by the fencing time.The number of individuals in the 0 to 10cm depth was highest than the other two soil layers in the 4-year fencing sample area,which representing 40.1％ of the total soil animal in this sample areas.Vegetation cover,the number of soil animal individuals and groups increased with the extension of fencing time.Diversity index H,evenness index E,richness index D,dominance index I and DIC index were continuously increases with extension of fencing time,but the peak of DIC index and the largest number of individual and group were found in sample areas fencing for 10 and 15 years,accounting for 3.99 and 3.29,respectively.The variation of A/C values varied with different fencing time.The value of A/C of 4-year fencing area was 2.67,and was higher than other fencing time,it can be regarded as biological indicator to assess the process of vegetation degradation and recovery in Lhasa semi-arid valley.