返青期休牧对玛多高寒草原植物群落特征的影响

针对高寒草原冬春草场退化及草畜不平衡问题,为遏制草地生态系统进一步退化、提高草地生产力,本研究于2018年在青海省玛多县玛查理镇冬春草场开展返青期休牧育草试验。试验采用随机区组设计,设置返青期休牧和返青期放牧两个处理,在休牧结束时期和牧草生长高峰期(7月10日和8月10日)分别进行草地植物群落调查。结果表明:相对于放牧草地,7,8月份休牧草地的禾本科牧草株高增加了236.33%和123.83%(P<0.05),盖度增加了41.13%和61.71%(P<0.05),地上总生物量增加58.66%和33.62%;休牧以后草地主要植物种由原来的沙生风毛菊(Saussurea arenaria Maxim)、山莓草(Sibbaldia procumbens Linn.)等变为紫花针茅(Stipa purpurea Griseb)、疏花针茅(Stipa penicillata Hand.-Mazz)等;休牧草地和放牧草地样点植物群落结构存在差异;休牧草地植物群落物种丰富度、辛普森指数、香农-维纳指数较放牧草地均有所增加。因此,返青期休牧在高寒草原的实施改善了草地植被恢复情况,优化了草地植物群落结构,增强了生态系统多样性。本试验可为退化高寒草原植被恢复及休牧制度的实施提供科学理论依据。

Effect of Rest-grazing in Regreen-up Period on Plant Community Characteristics of Maduo Alpine Steppe

This study was aimed to prevent degradation and improve forage-livestock imbalance of alpine grassland,so as to utilize alpine grassland sustainably and improve its productivity. The experiment of rest-grazing in regreen-up period was carried out in winter-spring pastures of Machali Town,Maduo County,Qinghai Province in 2018. A randomized block experiment was adopted and two treatments of grazing and rest-grazing during regreen-up period were set up. We investigated the plant community of degraded grassland in alpine grassland during the end of grazing period (July 10) and the peak period of forage growth (August 10). The results showed that:Compared with the grazing treatment,the plant height,coverage and aboveground biomass of gramineous forage in the rest grazing treatment in July and August significantly increased by 236.33% and 123.83% (P<0.05),41.13% and 61.71% (P<0.05),58.66% and 33.62%,respectively. The main plant species changed from Saussurea arenaria and Sibbaldia procumbens to Stipa purpurea and Stipa penicillata after rest-grazing during the regreen-up period. The plant community structure showed obvious differences between the rest-grazing and grazing treatment. The species richness,Simpson index and Shannon-Wiener index of plant community in rest- grazing grassland were higher than those in grazing grassland. Therefore,the implementation of rest-grazing in regreen-up in alpine grassland improved grassland vegetation restoration,optimized grassland plant community structure and enhanced ecosystem diversity. This experiment can provide scientific theoretical basis for vegetation restoration and grazing rest system of degraded alpine grasslands.