草原灌丛化对生态系统多功能性的影响

Research progress and perspectives on the impact of shrub encroachment on ecosystem multifunctionality

草原灌丛化现象在干旱半干旱区广泛发生,影响了生态系统的结构、过程和功能。生态系统具有同时提供多种功能的能力,即生态系统多功能性。灌丛化是否会引起草原生态系统多功能性的减少,其内在的作用机制又是什么?这些问题仍有待明晰。理解草原灌丛化对生态系统多功能性的影响,对于促进草原地区“草⁃畜⁃人”平衡和实现区域可持续发展至关重要。从响应规律、影响路径和控制因素三个方面总结评述了草原灌丛化对生态系统多功能性影响的研究进展,主要包括:(1)阐明了单一生态系统功能和多种生态系统功能对草原灌丛化的响应特征;(2)从生物路径、非生物路径以及气候变化和人类活动的影响方面探讨了灌丛化对生态系统多功能性的影响路径;(3)从灌丛化物种、灌丛化阶段和草原类型三个方面明晰了草原灌丛化对生态系统多功能性影响的控制因素。在此基础上,针对灌丛化对生态系统多功能性的影响机制,对生产⁃生态功能权衡的影响等方面对未来研究进行了展望,并面向可持续发展目标探讨了灌丛化生态系统的可持续管理路径。研究可为我国灌丛化草原的恢复和管理提供支撑。

Shrub encroachment into grasslands is a widespread phenomenon in drylands,which alters ecosystem structure,processes and functions.Ecosystems have the ability to provide multiple functions simultaneously(ecosystem multifunctionality).However,it remains unclear whether shrub encroachment results in reductions in grassland ecosystem multifunctionality and what are the underpinned mechanisms.Understanding the impact of shrub encroachment on multifunctionality can help promoting the balance between“grass⁃livestock⁃human welfare”and achieve grassland sustainable development.In this study,we synthesized the research progresses on the impact of shrub encroachment on ecosystem multifunctionality from the perspectives of response patterns,impact pathways and regulation factors.It mainly includes(1)illustrating the response of single function and multiple functions to shrub encroachment;(2)explicating the impact of shrub encroachment on ecosystem multifunctionality via biotic and abiotic pathways and how it is mitigated by climate change and human activities;(3)synthesizing the regulators(i.e.,shrub species,encroachment stages and grassland types)of the impact of shrub encroachment on ecosystem multifunctionality.Based on the syntheses above,we further made perspectives on the impact of shrub encroachment on multifunctionality and the tradeoffs between production⁃ecological functions.Finally,based on sustainable development goals,we discussed the potential ways to achieve sustainable development in the encroached ecosystems.This study can provide support for the restoration and management of encroached grasslands in China.