Abstract: The relationship between biodiversity and ecosystem function has been receiving great attention, however, previous studies have little focus on the ecosystem multifunctionality (EMF). In the present study, we quantified EMF based on 11 ecosystem functions, including plant community biomass, soil organic carbon and soil enzyme activities in Stipa breviflora desert steppe, and investigated the effects of different grazing intensities (control, No grazing, CK;Light grazing, LG;Moderate grazing, MG;and Heavy grazing, HG) on the relationship between plant diversity and EMF. The results showed that grazing significantly reduced plant diversity, individual ecosystem functions, and EMF (P<0.05), with EMF was 0.6, 0.25, -0.18, and -0.78 under LG, MG, and HG, respectively. Most of the individual ecosystem functions were significantly positively correlated with plant diversity under different grazing intensities (P<0.05). EMF was linearly positively correlated with plant diversity indexes, where the Shannon-Wiener index showed the best fit to EMF and it was the best predictor of changes in EMF. In summary, appropriate reduced stocking rate are required to achieve biodiversity conservation and sustainability of multiple ecosystem services and functions in desert grasslands.

Key words: Desert steppe, Grazing, Ecosystem multifunctionality, Plant diversity

摘要： 生物多样性与生态系统功能之间的关系备受关注，但是过去的研究很少关注生态系统的多功能性（Ecosystem multifunctionality，EMF）。因此，本研究以短花针茅（Stipa breviflora）荒漠草原为对象，在测定植物群落生物量、土壤有机碳和多种土壤酶活性等11种生态系统功能的基础上量化EMF，并探究不同放牧强度（对照，No grazing，CK；轻度，Light grazing，LG；、中度，Moderate grazing，MG；和重度放牧，Heavy grazing，HG）对植物多样性与EMF的影响。结果表明：放牧导致植物多样性、单一生态系统功能和EMF显著降低（P<0.05），不同放牧强度下EMF分别是0.6，0.25，-0.18和-0.78。不同放牧强度下，大多数生态系统单一功能都与植物多样性显著正相关（P<0.05）。EMF与植物多样性指数线性正相关，香农维纳指数与EMF的拟合结果最好，是预测EMF变化的最佳指标。因此，为实现荒漠草原生物多样性保护和多种生态系统服务和功能的可持续性，在草地管理中可适当降低载畜率。

关键词: 荒漠草原, 放牧, 生态系统多功能性, 植物多样性