围栏封育对三江源区退化高寒草地植物光合作用及生物量的影响

Effect of Enclosure on Vegetation Photosynthesis and Biomass of Degraded Grasslands in Headwater Area of Qinghai-Tibetan Plateau

在青海省果洛藏族自治州玛沁县选取4个不同退化程度的天然草地,以围栏封育和围栏外自由放牧草地作比较,调查草地围栏内外不同退化程度的植物群落组成和生物量,分别测定各植物群落光合速率和叶面积指数。结果表明:植物群落光合速率、叶面积指数和生物量随着退化程度的加剧而减小,围栏内植物群落的光合速率和叶面积指数和生物量均大于围栏外的植物群落(P<0.05);不同退化程度下围栏内外植物群落的光合速率、叶面积指数与生物量之间成显著正相关关系(P<0.05),且围栏内植物这3项指标间的相关系数大于围栏外植物(除光合速率和叶面积指数间的相关系数外)。围栏封育可以改变草地植物群落的光合作用速率和叶面积指数,有利于退化草地植物的生物量积累和植被恢复。

Plant community structure,biomass,photosynthesis rate and leaf area index（LAI） of grasslands at different degraded degrees inside and outside the fence were investigated in Maqin county of Qinghai province.Photosynthesis rate,LAI and biomass of plant communities decreased with the increase of degraded degrees.Three indicators inside the fence were significantly higher than outside.Correlation among photosynthesis rate,LAI and biomass were also calculated.Results indicated that these three indicators had positive correlation.The conclusion was that enclosure could improve degraded grasslands of Oinghai-Tibetan Plateau,and also promote the stability and sustainable development of alpine grasslands.