Effects of grazing intensity, soil variables, and topography on vegetation diversity in the subalpine meadows of the Zhongtiao Mountains, China.

摘要

Montane meadows in the Zhongtiao Mountains (located at 111 degrees 15'-112 degrees 37'E, 34 degrees 36'-35 degrees 53'N) of North China are important for local animal husbandry and the provision of ecosystem services. However, owing to poor management, serious degradation has occurred on these subalpine meadows. The aim of this paper is to present a quantitative analysis of effects of stocking rate, grazing intensity, soil and topography on the status and diversity of montane meadow communities and to provide direction for improved management. Three regions in the Zhongtiao Mountain meadows were selected for monitoring the impacts of stocking rates and different grazing intensities on the meadow plant communities. Forty-one plots of 10x10 m and quadrats of 1x1 m in each plot were set up to collect data on site characteristics and vegetation status in the three regions. The relationships between community composition and structure, species diversity, and grazing intensity, soil and topographic variables were analysed by multivariate methods (TWINSPAN, DCA and CCA). The results showed that nine meadow communities were identified by TWINSPAN. The first DCA and CCA axis identified a grazing intensity gradient, which illustrated that grazing intensity was an important factor influencing meadow types, composition and structure. Soil and topographic variables were also important to meadow vegetation, although most soil variables were sensitive to grazing intensity. Species richness, diversity and evenness were closely related to grazing intensity. It is concluded that grazing intensity and grazing method must be changed from the current heavy continuous grazing to rotational grazing to enable grassland rehabilitation to occur in the meadows of the Zhongtiao Mountains.