退化草原定量化放牧条件下土壤动物的比较研究

在以冷蒿（Artemisia frigda）、糙隐子草（Cleistogemes sprrosa）、冰草（Agropyron cristatum）、寸草苔（Carex duriusula）等为主的退化草原上,是置以4、8、12、16、20只内蒙古细毛羊和零只羊（对照区）指标定量化的牧压梯度系列（均为100×100m2面积的放牧围栏试验小区）的土壤动物比较研究表明：其中以8和12只羊小区的土壤动物群落结构复杂而稳定，8只羊小区的土壤动物数量高于12只羊小区；多样性指数、均匀度、丰富度两者均较高，丰富度前者大于后者，理论上，8只羊／公顷是较理想的牧压指标。4、16、20只羊小区的土壤动物种类和数量明显减少，多样性指数、均匀度均低、20只羊／公顷小区由于少数种类数量高至使多样性指数偏高；三者的丰富度均低，综合分析认定为不可取的牧压指标。植食和捕食性的土壤动物与牧压呈负关联，杂食和粪食性土壤动物则与收压呈正关联。土壤动物各类群中以鞘翅类（Coleoptera）随牧区梯度的改变而呈规律性变化，是较理想的监测草原退化的生物指标。

COMPARATIVE STUDY ON SOIL ANIMALS UNDER EXPERIMENTED GRAZING PRESSURES IN DEGENERATED GRASSLAND

The effects of experimented grazing pressures on soil animals were studied in InnerMongolia degenerated grassland. The results showed that the communities of soil animalson grasslands where the grazing pressures were 8-12 sheeps per hectare were complexand stable, and the biodiversity indexes were higher than that of under other grazing pressures-Under the grazing pressures of four, sixteen and twenty sheeps per hectare, thedensety of soil animals, the number of soil animal species and the biodiversity indexes arelower than that of eight and twelve sheeeps per hectare. It can be concluded that the grazingpressu res of eight and twelve sheeps per hectare are reasonable in degenerated grassland.There are negtive relationshiP between the herbivorous, carnivorous macrofauna andthe grazing pressures, and positive relationship between other species of macrofauna andthe grazing pressunes- Coleoptera takes on regular changes with the increase of grazingpressures and can be used as a biological index for rnonitoring the degeneration of grasslandi