青海湖流域高寒草原对放牧时间的响应

Response of alpine grassland to grazing time in Qinghai lake basin

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-种子成熟脱落后再放牧样地中植被群落的特征变化,为缓解青海湖流域高寒草原生态退化提供新的措施。采用野外随机样方调查方法,在刚察县哈尔盖镇冬春草场选定常规放牧与牧草返青前至种子脱落后放牧试验样地进行草地群落特征数据调查。研究表明:牧草返青前-种子成熟脱落后再放牧能显著提高高寒草原群落盖度与地上生物量;同时,放牧时间改变对高寒草原植物群落伴生种组成有一定影响,主要表现为优良牧草重要值显著增加,常规放牧时间下耐牧性品种占优;此外,放牧时间改变对群落丰富度有显著影响,但对群落多样性及均匀度没有显著影响。可见,牧草返青前-种子成熟脱落后再放牧能缓解高寒草原生态退化。

In order to find out new solutions for easing the degeneration of alpine meadow in Qinghai Lake basin, we took alpine meadow, which located in Ha Ergai town, Gangcha county, as a case that comparatively studied the different changes of vegetation community characteristics between conventional grazing area and the area where was only grazed before grass turning green and after seed maturing. We used field random quadrat survey to collect grassland data. The results showed that grazing before grass turning green and after seed maturing significantly increased alpine meadow community coverage and aboveground biomass. Meanwhile, grazing time also impacted the associated species composition,which was characterized by the increases of the importance values of excellent pasture, while the grazing resistance varieties were dominantly in conventional grazing area. In addition, grazing time had significant impact on Margalef, but no impact on Shannon-Wiener and Pielou. Obviously, grazing before grass turning green and after seed maturing can ease the degeneration of alpine meadow.