沙障对流动沙丘区地表节肢动物分布及多样性的影响

沙障作为人工固沙植被恢复与保护绿洲和道路安全的一种手段，可以有效阻止沙丘移动，改变流动沙丘地表生态水文过程，进而影响节肢动物多样性及营养结构及功能变化。鉴于此，选取临泽县中部沙带为研究区，利用陷阱法系统调查了生物、物理沙障和流动沙丘区沙丘不同部位地表节肢动物分布及多样性。研究结果表明，沙障营建强烈影响了流动沙丘区地表节肢动物组成，生物和物理沙障区地表节肢动物的活动密度、物种丰富度及多样性均显著高于流动沙丘区，捕食性和其它食性节肢动物较植食性节肢动物对沙障营建的响应更为敏感。沙障还改变了沙丘地表节肢动物的分布规律，生物和物理沙障区地表节肢动物的活动密度从沙丘底部到顶部依次增加，而流动沙丘区地表节肢动物主要分布在沙丘中下部。谢氏宽漠王和尖尾东鳖甲在流动沙丘区主要分布沙丘的中下部，沙障营建导致沙丘顶部谢氏宽漠王和尖尾东鳖甲的活动密度大幅提高。此外，研究还发现生物和物理沙障对地表节肢动物的影响不同，生物沙障区地表节肢动物活动密度显著高于物理沙障区，捕食性和东鳖甲属等其它食性节肢动物的活动密度在生物沙障区均高于物理沙障区。总之，沙障营建及类型差异强烈影响地表节肢动物的分布及多样性，它通过资源上行效应和土壤物理环境的改变提高了地表节肢动物的多样性及营养结构，从而影响了土壤生态系统结构及功能变化过程。

Effects of sand barriers on the distribution and diversity of ground arthropods in the active sandy dune regions

As a means of artificial sand fixation for vegetation restoration and protection for oases and road safety, sand barrier can effectively prevent the movement of sand dunes, strongly affect the distribution and diversity of ground arthropods by altering abiotic and biotic environment on the surface of the dunes. Moreover, sand barrier also impacted on the trophic structure and ecological function of ground arthropods by changing the surface eco-hydrological process of active sandy dune regions. Therefore, we select the middle sand strip as the object of study in Linze County in the middle reaches of Heihe River Basin and systematically researched on the distribution and diversity of ground arthropods using pitfall trapping in the biological sand barrier, physical sand barrier and active sandy dune regions. The key results are as follows. Sand barrier strongly affected the assemblage of ground arthropod community. The activity density, species richness and diversity index of ground arthropods in the biological sand barrier and physical sand barrier regions were significantly higher than those in active sandy dune regions apparently. Comparing with the phytophagous arthropods, the predatory arthropods and other arthropods response was more sensitive to sand barrier construction. Sand barrier also changed the distribution pattern of ground arthropods in the upper, middle and bottom of sandy dune. The activity density of ground arthropods in biological sand barrier and physical sand barrier regions increased from the top to the bottom of the sandy dune gradually. Conversely, it distributed in the middle and bottom of sandy dune in the active sandy dune regions which was related to the quantity changes of ground-dwelling arthropods species that preferred to move in the active sandy dune regions. More Mantichorula semenowi and Anatolica mucronate were collected at the middle of bottom of sandy dune in the active sandy dune regions, and those beetles were collected at the up of sandy dune in the biological sand barrier and physical sand barrier regions. Besides, it was also found that the influences on ground arthropod assemblage of biological sand barrier and physical sand barrier were different. The activity density of ground arthropods in the biological sand barrier regions was higher than physical sand barrier regions. A similar pattern was observed on the activity density of predatory arthropods and other arthropods like Tentyria sp. In conclusion, sand barrier presence and its types strongly affected on the diversity and trophic structure of ground arthropods community. It significantly improved the number of individuals and diversity of ground arthropods by bottom-up effect of resource and changes of the soil physical environment, accelerating the process of soil ecosystem structure and functional change in the desert ecosystem.