放牧时间对青海湖流域冬春草场高寒草原群落特征的影响

为缓解青海湖流域高寒草原生态退化提供新的措施,以青海湖北岸刚察县哈尔盖镇冬春草场高寒草原为研究对象,对比研究传统放牧样地与牧草返青前至种子成熟脱落后再放牧样地中植被群落的特征变化。试验以野外样方调查为主。结果表明:牧草返青前至种子成熟脱落后再放牧能显著提高高寒草原群落盖度;同时,放牧时间改变对高寒草原植物群落亚优势种与伴生种组成有一定影响,主要表现为禾本科牧草重要值显著增加,而常规放牧时间下耐牧性较强的莎草科牧草重要值增加,但两者对牧草优势种组成没有显著影响;此外,放牧时间改变对群落多样性及均匀度没有显著影响。放牧时间改变能一定程度缓解高寒草原退化。

Impact of grazing time on winter and spring pasture community characteristics at Qinghai lake drainage basin

In order to find out new solutions for decreasing degeneration of alpine meadows at Qinghai Lake drainage basin,we took the winter and spring alpine meadow that located in Haergai town,Gangcha as cases,and comparatively studied the different changes of vegetation community characteristics between conventional grazing area and the area only grazed before grass turning green and after seed maturing. The results show that grazing before grass turning green and after seed maturing significantly increases alpine meadow community coverage. Meanwhile,Changes on grazing time also have impact on associated species composition of subdominant species and companion species in alpine meadow community,which is characterized by the increases of the importance values of grass,but the importance values of sedges increases,which is resistant to grazing in traditional grazing model. Both grazing ways don＇t have significant impact on composition of grass dominant species;In addition,the changes on grazing time have no significant impact on the community diversity and uniformity. Obviously,grazing before grass turning green and after seed maturing can ease the degeneration of alpine meadow.