森林生态系统多功能性及经营优化途径

Forest ecosystem multifunctionality and optimizing management pathway

人类活动、全球变化和生物多样性丧失将对生态系统功能、服务和稳定性造成严重影响。提升森林质量,增强生态系统多种功能(如固碳增汇、水源涵养),是生态文明建设(尤其是实现碳中和目标)的重大战略需求。本文主要目的是基于生态系统多功能性评价方法,在林分和景观尺度上探讨森林质量提升策略和途径,系统总结和分析生态系统多功能性概念和评价方法、生物多样性对生态系统多功能性的影响机制。目前,对森林生态系统中生物多样性与单个功能(如生产力)的关系及作用机理已有较为清晰的认识,但生物多样性对生态系统同时提供多种功能(多功能性)的影响及维持机制仍缺乏深入理解。特别是在现实自然条件下,森林群落结构复杂,树种组成的构建呈现非随机性,生物类群间相互作用及其对各功能的贡献不同,生态系统多功能性受树种组成、林龄、群落结构和环境(气候、土壤)等诸多生物和非生物因素的影响,解析树种组成、生物多样性对森林多功能性的影响及维持机制是亟待突破的难点。在景观尺度上,按照森林类型和自然条件的空间分割(Spatial segregation),依据分类—分享经营策略(Sparing-sharing strategy),对单功能林和多功能林进行空间格局优化,提升景观整体的多功能性。在林分水平上,针对森林的优先经营目标,采用不同的经营策略。保护性(Protective)森林以近自然过程恢复生物多样性;生产性(Productive)森林通过集约经营提高森林生产力;多功能林通过轻度经营增强生态系统多功能性。

Human activities,global change and biodiversity loss have unpredictable effects on ecosystem functions,services and stability.Improving the quality of forest resources and enhancing ecosystem functions(i.e.carbon sequestration and water conservation)are the key elements of ecological civilization construction and carbon neutrality.This article attempted to use the assessment method of ecosystem multifunctionality to discuss the strategies for improving forest resource quality at stand and landscape scales.The definition and assessment methods of ecosystem multifunctionality as well as the underlying mechanisms that biodiversity affects ecosystem multifunctionality have been systematically reviewed.The effects of biodiversity on a single ecosystem function(such as productivity)and its mechanisms have been clearly unveiled.However,how biodiversity affects multiple ecosystem functions(multifunctionality)and the underlying mechanisms are far away from a resolved issue.Under real natural conditions,complicate community structure and non-random tree species assembly in forests lead to different effects of tree species and their interaction on ecosystem functions.Meanwhile,tree species identity,stand age and community structure together with abiotic factors(i.e.climate and soils)affect the multifunctionality of forest ecosystems,making it a critical issue to unveil the effect mechanisms of tree species identity and biodiversity on the multifunctionality of the ecosystem.At the landscape level,spatial optimization of forest management for different forest types can enhance multifunctionality based on the sparing and sharing strategies.At the stand or ecosystem level,the increase in biodiversity through natural restoration for protective forests,intensification for productive forests,and moderate scale management for multi-functional forests are recommended to improve stand quality and multifunctionality of forest resources.