生态阈值研究进展

Review on recent advances in ecological threshold research

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。主要有两种类型生态阈值点(ecologicalthresholdpoint)和生态阈值带(ecologicalthresholdzone)。在生态阈值点前后,生态系统的特性、功能或过程发生迅速的改变。生态阈值带暗含了生态系统从一种稳定状态到另一稳定状态逐渐转换的过程,而不像点型阈值那样发生突然的转变。后者在自然界中可能更为普遍。在自然资源保护和生态系统可持续管理中,生态阈值研究有着重要的理论和实践意义,受到生态学和相关学科的密切关注。其研究已经在森林、草原、湖泊、海洋等生态系统,从不同角度,针对不同生态因子广泛开展。由于生态因子相互作用的复杂性,有关生态阈值的性质及其在不同空间尺度上的联系仍然存在很大的不确定性。在未来的研究中必须加强综合和定量化研究,进一步提高应用生态阈值的能力。在全球变化和生态响应研究领域,生态阈值研究将会有更大的发展空间。

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. There are two main types of ecological thresholds that can theoretically occur in natural systems, ecological threshold point and ecological threshold zone. The attributes, function or process of an ecosystem will change abruptly around the point-type threshold. Zone-type ecological thresholds imply a more gradual shift or transition from one state to another, rather than an abrupt change at a specific point in time, as suggested in point-type threshold. Zone-type ecological thresholds are probably more common in nature than point-type thresholds. Research on ecological thresholds has important theoretical and practical meanings for natural resources conservation and sustainable ecosystem management, which have been the highlights in ecology and related areas. A lot of research on ecological threshold has been carried out in forest, grassland, lake and ocean ecosystems for different ecological factors and from different points of view. There is still great uncertainty about the nature of ecological thresholds and how they are related in different spatial scales. More synthetic and quantitative study is needed to improve the ability of applying knowledge of ecological thresholds in ecosystem management. Much progress and research will be made in the areas of global change and ecological responses.