高原鼠兔对大通河上游高寒草甸草地的影响

Effect of plateau pikas on Alpine meadow grassland in upstream of Datong river

通过对祁连山地区不同退化高寒草甸中高原鼠兔洞口密度与植物群落的关系的研究分析表明:随着高寒草甸退化程度的加剧,植物群落的盖度、地上生物量、优良牧草的地上生物量逐渐减少,植物群落的优势种也逐渐由高山嵩草—禾本科牧草—毒杂草转变;鼠兔的洞口密度先增加,在中度退化时达到最高(2391个/hm2),然后降低;在高寒草甸退化过程中,高寒草甸植被盖度与鼠兔洞口密度呈二次函数关系。此外,当鼠洞密度达到中等水平时,优良牧草生物量、植物地上生物量和植物高度达到最小值,证实了由于鼠类活动参与而有悖于"中度干扰假说"的理论。

The relationship between plateau pikas burrow densities and plant community in different degraded alpine meadow in Qilian mountain areas was studied. The results showed that the cover of plant communities,aboveground biomass,excellent pasture biomass decreased. With increasing degree of degradation in alpine meadow,the dominant species of plant communities gradually change from Gramineae grasses to Alpine Kobresia and to poisonous grasses.Plateau pikas burrow densities firstly increased and reached a maximum in the medium degraded grassland( 2391 /hm2),then decreased. During the degradation process of alpine meadow,the cover of alpine plant communities and plateau pikas burrow densities reflect relationship of quadratic equation. In addition,when plateau pikas burrow densities reached a medium level,index of excellent forage biomass,aboveground biomass and plant height reached minimum,which confirmed the activities of plateau pikasthe goes against medium disturbance hypothesis theory.