生态阈值是指生态系统从一种状态快速转变为另一种状态的某个点或一段区间，推动这种转变的动力来自某个或多个关键生态因子微弱的附加改变。生态阈值现象普遍存在于自然生态系统中。在自然资源保护和生态系统可持续管理中，生态阈值起着重要的作用。加强生态系统阈值的研究，对维护生态系统稳定性、防灾减灾、保护生物多样性，对建立经济可持续发展模式，研究和预防全球气候变暖方面具有重要的指导作用。由于生态因子相互作用的复杂性，生态阈值的性质及其在不同空间尺度上的联系等方面仍然存在很大的不确定性。

An ecological threshold refers to a point or zone in the relationship between two or more ecological variables at which relatively abrupt change occurs from one ecological condition to another in an ecosystem. The impetus for this change comes from a small additional change in one or more key factors. Ecological thresholds are ubiquitous in natural ecosystems. Research on ecological thresholds has important theoretical and practical meanings for natural resources conservation and sustainable ecosystem management. Enhancing the research of the ecological threshold has great guiding effects on maintaining the stability of ecosystems, preventing and reducing the disasters, protecting the biodiversity, establishing the economic mode of sustainable development, and studying and preventing the global warming. Because of the complexity of the interaction of ecological factors, there is still great uncertainty about the nature of ecological thresholds and how they are related in different spatial scales.