封育和放牧对典型草原地上植被的影响

Effects of Fencing and Grazing on Aboveground Vegetation

封育和放牧是草地生态系统重要的干扰因子。以黄土高原典型草原封育5年草地和放牧地为研究对象,采用野外调查方法,地上植被物种组成、生物量、盖度、密度、地上茎分枝数和物种多样性等,以期揭示封育和放牧干扰对地上植被的影响。结果表明:封育和放牧对地上植被群落结构有显著影响。与放牧地相比,封育措施显著增加了典型草原的地上生物量和总盖度,但显著降低了地上植被密度和地上茎分枝数。封育措施显著提高草地禾草生物量,显著降低非禾草生物量。封育措施降低了禾草和非禾草地上茎分枝数,但非禾草地上茎分枝数下降不显著。封育显著降低了地上植被的物种丰富度、Margalef指数和Shannon-Wiener多样性指数,但对Simpson指数和Pielou指数影响不显著。

Fencing and grazing are important factors in grassland ecosystem. Based on the investigation data, the influence of fencing and grazing on species composition, biomass, cover, density, shoot numbers and species diversity of aboveground vegetation had been examined in typical steppe on the Loess Plateau. Results showed that fencing and grazing had significant influence on vegetation structure. Compared with grazing, fencing significantly increased total cover and aboveground biomass, but significantly reduced the density of vegetation and shoot numbers. Fencing significantly increased grass biomass of aboveground vegetation, but significantly decreased forb biomass of aboveground vegetation. Fencing significantly reduced grass shoot numbers, but had no significant effects on forb shoot numbers. Fencing and grazing significantly affected species richness, Margalef index and Shannon-Wiener diversity index, but had no significant effect on Simpson index and Pielou index. Compared with grazing, fencing significantly reduced the species richness, Margalef index and Shannon-Wiener diversity index of aboveground vegetation.