高寒草甸植被群落特征及其营养品质对围栏封育的响应

为探究长期封育对高寒草甸植被功能群落特征和营养品质年际动态的影响，本研究以围封11年和连续放牧高寒草甸为研究对象，采用3年连续野外群落调查和室内牧草营养品质分析相结合的方法，比较了长期围封和连续放牧2种草地管理措施对5个植被功能群特征和营养品质的影响。结果表明：围封样地禾本科（Grass group，GG）、莎草科（Sedge group，SG）、豆科（Leguminous group，LG）和杂类草（Forbs group，FG）4个功能群盖度和地上生物量显著高于放牧样地（P<0.05），功能群密度、物种丰富度指数、Shannon-Wiener指数、粗蛋白（Crude protein，CP）和体外干物质消化率（In vitro dry matter digestibility，IVDMD）显著低于放牧样地（P<0.05）；围封样地4个功能群的密度、群物种丰富度指数、Shannon-Wiener指数、CP和IVDMD表现出不受年际降雨量影响而逐渐下降的趋势。研究建议对围封11年的高寒草甸可进行适当的放牧以增加植被功能群物种多样性和牧草营养品质。

Responses of Plant Functional Group Traits and Nutritional Quality to Fencing in an Alpine Meadow

In order to explore the effects of long-term fencing on inter-annual dynamics of plant functional group traits and nutrientional quality in an alpine meadow, we took 11-year fenced and continuously grazed alpine meadow as the study area by combining 3-year continuous field investigation and indoor forage nutritional quality analysis. The effects of long-term fencing and continuous grazing on 5 plant functional group traits and nutritional quality were compared, and then. The results showed that, the coverage and aboveground biomass of Grass group (GG), Sedge group (SG), Leguminous group (LG) and Forbs group (FG) in the fenced area were significantly higher than those in the grazing plot (P<0.05), while functional group density, species richness index, Shannon-Wiener index, Crude protein (CP) and In vitro dry matter digestibility (IVDMD) were significantly lower than those of the grazing plots (P<0.05). The density, species richness index, Shannon-Wiener index, CP and IVDMD of 4 functional groups were not affected by inter-annual rainfall without a gradually decreased trend in the fenced plot. Thus, it suggested that the appropriate grazing should be carried out in the 11-year fenced field to increase the species diversity and nutritional quality of herbage in the alpine meadow.