青海湖北岸不同土地利用方式对大型土壤动物群落的影响

摘要

To investigate the effects of different land-use styles on soil animal communities in the grasslands of the northern region of Qinghai Lake,the larger-size soil animals from 10 different sites were investigated.A total of 657 animals (belonging to 3 classes 9 orders 13 taxonomic groups) were collected,with larval Coleopteran (beetles),larval Diptera and adult Coleopteran as the dominant groups.Compared with former related studies in other regions in the northwest of China,the northern region of Qinghai Lake had rather low numbers (11 individuals per 50 cm×50 cm×20 cm quadrat) and diversity,perhaps due to the arid nature of the area.Compared with three other original grassland types,abandoned land in the Guoluozang County area,soil animals were very scarce,while in the reseeded land there were significantly larger numbers of soil animals,indicating that cultivations had destructive effects on the Achnatherum grassland,while manual activities might be helpful for the recovery process.In the Lanniwan area,there were no differences in animal numbers,biomass and biodiversity between 18-years and 6-years enclosed grassland,but the unfenced grazing channel had significantly lower numbers and animal biomass than the two enclosed grasslands,indicating the negative effects of degraded vegetation and soil conditions on soil animal communities.In the River Beach area,there were no differences of animal biomass,number and biodiversity between the grazing channel and the enclosed meadow steppe,perhaps due to the humid soil environment in the area.%为了解青海湖北岸不同土地利用方式对草地生态系统中土壤动物群落特征的影响,对这一地区不同样地中的大型土壤动物进行了调查.共捕获大型土壤动物657只,隶属3纲9目13个类群,优势类群为鞘翅目幼虫、双翅目幼虫和鞘翅目成虫.研究表明,青海湖北岸草地生态系统中大型土壤动物数量总体稀少,生物多样性较低,推测干旱可能是导致这一现象的主要原因.在果洛藏村样区,弃耕地中大型土壤动物类群极为匮乏,远低于3种原生草地,而补播地的土壤动物个体数显著高于(P＜0.05)弃耕地,已与对应的原生草地相当,可见人为耕种对芨芨草原生草地中大型土壤动物群落具有毁灭性的破坏作用,而人工干预措施可以促进土壤动物群落的恢复进程.在烂泥湾样区,18年封育草地和6年封育草地生物量、个体数及多样性指数都无显著差别,而放牧通道内大型土壤动物生物量和个体数都显著低于以上2种封育草地类型(P＜0.05),充分体现出放牧通道内植被和土壤条件恶化对大型土壤动物的不利影响.在铁路南河边滩地样区,放牧通道内大型土壤动物生物量、个体数及多样性指数与长期封育草原草甸都无显著差别(P＞0.05),可能与这一样区内土壤较湿润有关.