短花针茅草原生态系统稳定性对放牧的响应

Response of Stipa breviflora desert steppe ecosystem stability to grazing

摘要:

为探讨不同放牧强度与生态系统稳定性的关系，在内蒙古短花针茅荒漠草原野外放牧试验基地(2004 年开始放牧)展开研究。试验采用完全随机区组设计，设置 4 个不同的放牧处理：对照 (CK)、轻度(LG)、中度(MG)、重度(HG)放牧，3 个区组(3 个重复)。2019 年对植物群落的物种数、盖度、密度、生物量进行观测，采用 Gordon 稳定性方法评估不同放牧强度对群落稳定性的影响。结果表明：随着放牧强度的增大，植物群落物种数、生物量和盖度显著降低(P＜0. 05)，密度随放牧强度的增加呈先增加后降低的趋势，在中度放牧时最高。植物群落多样性指数与群落物种数、盖度、生物量呈显著相关性(P＜0. 05)。植物群落多样性随放牧强度增加而降低，中度放牧强度下群落稳定性最高。

Abstract:

To explore the relationship between grazing intensity and ecosystem stability，a manipulative experi- ment was carried out in the desert steppe of Stipa breviflora in Inner Mongolia. The experimental design was a com- pletely randomized block design with four different grazing treatments： control (CK)，light grazing (LG)，moderate grazing (MG)，and heavy grazing (HG)，each with 3 replicates. During the experiment in 2019，the number of spe- cies，coverage，density and biomass of plant communities were observed. Besides，the Gordon stability method was used to evaluate the impact of different grazing intensities on community stability. The results showed that with the in- crease of grazing intensity，the number of species，biomass and vegetation coverage of the community decreased sig- nificantly(P＜0. 05). The results also implied that the density of the community increased first and then decreased with the increase of grazing intensity，and reached the highest in moderate grazing. The plant community diversity in- dex and community species，coverage and biomass had significant correlation(P＜0. 05). The diversity of plant com- munity decreased with the increase of grazing intensity，and the community stability was the highest at moderate graz- ing intensity.