克氏针茅草原群落物种多样性与生物量关系对放牧强度的响应

放牧强度引起的草原植物群落物种多样性与地上生物量变化是近年来草地生态系统研究的热点问题。以内蒙古锡林郭勒克氏针茅草原为研究对象，探究植物群落结构特征、物种多样性与地上生物量之间相互关系及其对不同放牧强度的响应。结果表明：随着放牧强度的增加植物群落结构逐步向退化方向演替；植物群落高度逐渐降低（P<0.05），密度逐渐增加（P<0.05），盖度总体呈下降趋势（P<0.05）；植物群落和原有群落优势种地上生物量总体呈下降趋势（P<0.05），而退化指示物种的地上生物量逐渐增加（P<0.05）；轻度、中度放牧条件下群落物种Margalef指数、Pielou指数、Simpson指数均显著高于重度放牧（P<0.05）；地上生物量与Shannon-Wiener指数、Margalef指数和Pielou指数呈正相关关系，而与Simpson指数呈负相关关系。综上所述，克氏针茅草原植物群落结构和功能在不同放牧强度下产生不同的响应，适度放牧有利于提高群落物种多样性与生物量。

Relationship between species diversity and biomass of Stipa krylovii steppe community and its responses to grazing intensity

In recent years, the species diversity and aboveground biomass changes of steppe plant communities caused by grazing intensity have been hot issues in steppe ecosystem research. This paper takes the Stipa krylovii steppe of Xilin Gol in the Inner Mongolia as the research object, explores the relationship between characteristics of plant community structure, species diversity and aboveground biomass, and clarifies response to different grazing intensities. The results showed that the plant community structure gradually succeeded in the direction of degradation with the increase of grazing intensity. The height of the plant community gradually decreased (P<0.05) while the density of that gradually increased (P<0.05), and the overall coverage showed a downward trend (P<0.05). The aboveground biomass of plant communities and the dominant species of the original community showed a general downward trend (P<0.05), while that of the degraded indicator species gradually increased (P<0.05). The Margalef index, Pielou index, and Simpson index of community species under mild and moderate grazing conditions were significantly higher than those of heavy grazing (P<0.05). Aboveground biomass was positively correlated with Shannon-Wiener index, Margalef index and Pielou index, but showed a negative correlation with the Simpson index. In summary, the structure and function of the Stipa krylovii steppe plant community produce different responses in different grazing intensities, and moderate grazing is beneficial to increase the community''s species diversity and biomass.