内蒙古荒漠草原植物群落特征对放牧利用和降水条件的响应

The Response of Plant Community to Grazing and Precipitation in Desert Steppe of Inner Mongolia

研究放牧利用与降水条件对植物群落特征的影响,有助于揭示植物群落对放牧利用与水热变化的响应机制。以内蒙古四子王旗短花针茅荒漠草原放牧样地为研究对象,通过对2005~2015年降水条件和草地植物群落特征的长期连续监测与量化分析,探讨植物群落特征对放牧利用和降水条件的响应。结果表明:降水波动对地上现存量、群落盖度、群落高度与Margalef丰富度指数的影响不受重度放牧利用的干扰,而且重度放牧利用对植物群落地上现存量、群落盖度、群落高度与Shannon-wiener多样性指数的消极影响与降水年份类型(干旱年、正常年和湿润年)无关。但是,重度放牧利用对Margalef丰富度指数的影响与降水年份类型有关,在干旱年和湿润年Margalef丰富度指数在禁牧控制区大于重牧利用区,在正常年Margalef丰富度指数在禁牧控制区与重牧利用区之间不存在显著差异。

Siziwang Banner Stipa breviflora desert steppe in Inner Mongolia was chosen as the experimental area to explore the response of plant community to grazing utilization and precipitation conditions using long-term continuous monitoring and quantitative analysis of precipitation condition and the grassland plant community characteristics from 2005 to 2015.The results showed that the fluctuation of precipitation on aboveground standing crops(AGSC),community coverage(CC),community height(CH)and Margalef richness index(Ma)was not affected by heavy grazing.Moreover,the negative effect of heavy grazing on AGSC,CC,CH and Shannon-wiener diversity index(H)was not related to the type of yearly precipitation(DY:dry year,NY:normal year,WY:wet year).However,the effect of heavy grazing on Margalef richness index(Ma)was related to the type of yearly precipitation.In the dry or wet years,the value of Ma in the grazing prohibition area was greater than that in the heavy grazing area.In normal years,there was no significant difference between the grazing prohibition area and the heavy grazing area.