生态安全阈值研究述评与展望

随着全球变化的加剧,生态环境不断受到干扰和损害,生态安全问题日益突出。21世纪以来,生态系统风险或安全评估已成为全球变化和生态学研究的国际前沿和热点,其不同尺度不同类型生态安全阈值的判别和认知是生态系统风险或安全评估的关键和核心,更是全球变化胁迫下生态系统适应性管理的基础。本研究以生态系统不同胁迫要素为切入点,对生态安全阈值研究理论与实践发展进行了综述,大量文献显示通过提高生态安全阈值的判别和预估水平,不仅可揭示生态系统稳态转化与气候变化、碳氮循环、土地和草地利用、区域政策制度等胁迫因子的相互作用关系,而且对于退化生态系统修复及其生态环境保护与管理意义重大。当然,鉴于不同胁迫因子及其不同类型生态系统结构健康性及服务功能可持续性判别的复杂性,生态安全阈值厘定和预测能力极为有限,仍存在很大不确定性。

Overview and prospects for ecological safety threshold research

With global change intensifying,the ecological environment has been disturbed and damaged,resul-ting in increasingly evident ecological security problems.During the 21st century,ecosystem risk (or safety) assessment has become an internationally recognized discipline at the forefront of global change and ecology re-search.A key object of ecological safety research is to identify and understand the tolerance threshold of the different types of ecosystems at various scales and the processes of adaptive management of ecosystems under global change stress.This paper takes the different elements affecting ecosystems as the starting point to re-view the theory and application of the ecological safety threshold concept.The literature reveals the interrela-tionship between ecological steady-state processes and perturbations of climate change,impacting on carbon and nitrogen cycles,with a consequent need for changes to land and grassland use,and regional policy regimes, among others.Furthermore,improving detection of ecological safety thresholds in major ecosystems and the precision of forecasts about their behavior is pivotal to restoration of degraded ecosystems and the protection and management of the ecological environment.Because of the complexity of the changes to ecosystem proces-ses induced by the various stress factors,and gaps in knowledge about the processes themselves,especially in relation to defining health and sustainability in different types of ecosystem,the determination and predictive capability pertaining to the ecological safety threshold is currently very limited,and there is still great uncer-tainty.