围封与放牧对青藏高原草地生物量与功能群结构的影响

Effect of Fencing on Plant Biomass and Functional Group Structure of Different Types of Degraded Grassland in Qinghai-Tibet Plateau

以青藏高原高寒草甸、高寒草原、温性荒漠草原的退化草地为基础,比较了5年围封样地与放牧样地的生物量和群落结构。结果表明：（1）围封后3类草地地上总生物量较放牧样地分别显著增加了48.1%、10.8%、34.5%;地下生物量对围封的响应与地上总生物量一致,且围封后高寒草原0-10cm土层根系生物量比例较放牧地显著下降。（2）围封显著降低了高寒草甸的根冠比,高寒草原和温性荒漠草原无显著变化。（3）与放牧地相比,围封显著增加了高寒草甸和高寒草原禾本科植物的生物量比例,高寒草甸杂类草显著降低,温性荒漠草原功能群生物量比例无显著差异。

Based on three types of degraded grassland：alpine meadow,alpine steppe and temperate desertsteppe in Qinghai-Tibet plateau,we analyzed the effect of fencing and grazing on different types of degraded grassland communities.The research results indicate that：（1）The abovegound biomass of three types of grassland increased by 48.1%,10.8%and 34.5%,respectively after five years of fencing.The responsing of underground biomass of three types of grassland were consistent with the aboveground biomass.（2）The propotion of upper-layer（0-10cm）root biomass of alpine steppe and the root-shoot ratio of alpine meadow indicating a‘clear decling trend＇while compared with the grazing land.（3）The gramineous plants,which occurred in a higher propotion in the total biomass in feacing grassland than it of grazing on alpine steppe and alpine meadow.Nevertheless,the proportion of troublesome weed in alpine steppe declined significantly and had no significant effects in temperate desert-steppe.