天然和人工固沙灌木林蜘蛛和甲虫分布与环境因子的关系

干旱区人工植被恢复驱动的土地利用变化强烈影响了地表和土栖的节肢动物群落结构及多样性。然而，我们对地表节肢动物群落关键类群-蜘蛛和甲虫对固沙植被恢复的响应及与环境变化关系的认识还很有限。以天然固沙灌木林和2种人工固沙灌木林为研究对象，运用方差分析和多变量分析等方法定量研究了干旱区天然和人工固沙植被区地表蜘蛛和甲虫分布特征及影响要素。结果表明，天然灌木林与人工梭梭、柽柳林地表蜘蛛和甲虫群落组成明显不同，人工梭梭、柽柳林地表蜘蛛活动密度和甲虫多样性均显著高于天然灌木林，而地表甲虫密度和蜘蛛多样性变化与之相反。两种人工固沙灌木林之间蜘蛛和甲虫群落组成也存在一定差异，人工柽柳林地表蜘蛛活动密度、多样性和甲虫物种丰富度均显著高于人工梭梭林。进一步分析发现，蜘蛛群落中狼蛛科、平腹蛛科、皿蛛亚科和球蛛科与甲虫群落中拟步甲科、步甲科和象甲科等一些甲虫种属对3种生境的选择模式不同决定了蜘蛛和甲虫群落聚集结构。植被、土壤环境因子与蜘蛛和甲虫pRDA和pCCA结果表明，草本生物量、凋落物量、土壤含砂量、电导率和灌木盖度是影响蜘蛛分布的主要环境因子，它们解释了82.1%的蜘蛛群落变异；灌木盖度、草本生物量、土壤pH和砂含量是影响甲虫群落分布的主要环境因子，它们解释了60.6%的甲虫群落变异。总之，人工固沙灌木恢复影响了植被和土壤环境，它们相互作用改变了荒漠-绿洲过渡区蜘蛛和甲虫等地表节肢动物的分布格局。

The relationship of ground spider and beetle assemblage with environmental factors in the natural and artificial fixed-sand shrub forests

Land use change forced by artificial-fixed sandy vegetation recovery in an arid area has influenced the community and diversity of ground-dwelling arthropods. Up to now, few investigators have focused on responses of ground spider and beetle communities to artificial fixed-sand vegetation reconstruction, and its key influencing elements. In this study, two shrubs planted types (Haloxylon ammodendron plantations, HAP and Tamarix ramosissma plantations, TRP) without irrigation and natural shrub forest (natural shrub forest, NSF) selected for comparison with the shrub planted habitat as control. Ground spider and beetle communities in the three habitats collected by pitfall trapping, and environmental aspects related to the scattering of spiders and beetles were explored. One-way analysis was used to compare the difference of the activity density, taxa richness and Shannon-Wiener diversity of ground spiders and beetles as well as soil and vegetation factors among the three habitats. Further, analysis of variance and multivariate analysis was used to show the difference of ground spiders and beetles among three habitats. Redundancy analysis (RDA) and Canonical correlation analysis (CCA) were performed to quantify the relative contribution of the vegetation and soil ecological factors to the variation in the ground spider and beetle assembly and to identify key drivers of changes in these compositions. The results showed that significant differences in the diversity and the composition of the community on ground spiders and beetles were observed among the three habitats. Further, the activity density of ground spiders and the Shannon-wiener index of ground beetles in HAP and TRP habitats was greater than that in NSF habitats, a contrary pattern on the activity density of ground beetles and the Shannon-wiener index of ground spiders was observed. There are likewise some differences in the composition of spider and beetle communities between HAP and TRP habitats. The activity density and Shannon-wiener index of ground spiders and species richness of ground beetles in TRP habitats were higher than those in HAP habitats. The further analysis we discovered that Lycosidae, Gnaphosidae, Linyphiinae, Theridiidae, and some beetle species belonged to Tenebrionidae, Carabidae, Curculionidae were preferred for NSF or HAP or TRP habitats, which determined the assemblage of ground spiders and beetles. The consequences of pRDA show that herbaceous biomass, litter production, soil sand content, soil electrical conductivity and shrub cover were key environmental factors affecting the distribution of ground spiders, which contributed to 82.1% of the variation in the ground spiders. And the consequences of pCCA show that shrub cover, herbaceous biomass, pH and soil sand content were fundamental environmental factors affecting the distribution of ground beetles, which contributed to 60.6% of the variation in the ground beetles. In short, the restoration of artificial sand-fixing shrubs drives the change of vegetation and soil environment, which determined the distribution pattern of ground spiders and beetles in the desert-oasis transition zone.