斑块边缘效应的定量评价及其生态学意义

Quantitative assessment of patch edge effects and its ecological implications

边缘效应是生态系统 (斑块 )边缘和生态过渡区所呈现出的生态效应。但由于景观性质、研究目标和斑块形状的变化 ,边缘效应影响的范围和程度差异较大。核心斑块与周边景观之间的相似性既可以增强边缘效应 ,也可以减弱边缘效应。正确理解和确定边缘效应的影响范围和程度直接关系到对野外环境观测数据的科学使用。许多情况下 ,由于未能正确认识一个生态系统(斑块 )的边缘效应 ,时常会将在边缘效应地区获得的数据与系统内部核心区的观测数据混淆使用 ,得出一些不科学的结论。边缘效应的定量评价对于进行科学的野外环境观测 ,及其在自然保护区功能区设计和生物多样性保护中具有重要意义。但如何定量评价生态系统 (斑块 )的边缘效应目前还缺乏科学有效的方法。从分析边缘效应的概念和影响因子出发 ,结合地理信息系统 ,提出了开展定量评价斑块边缘效应的方法 ,并探讨了定量研究边缘效应的生态学意义。

Edge effects refer to the variation of certain ecological processes across the boundaries or the transition zones between different ecosystems. The magnitude and extent of landscape edge effects vary according to the level of landscape heterogeneity, the targets of interest, and the spatial configuration of landscape patches. The similarity between core patches and surrounding landscape could enhance or reduce edge effects. Understanding landscape edge effects is, therefore, critical to the appropriate use of environmental data collected through field surveys. Unfortunately, landscape edge effects are often neglected and as a result, data obtained in the areas under the influence of edge effects and acquired within the core areas are mixed in use. This often leads to absurd conclusions. Therefore, the quantitative assessment of landscape edge effects is important not only to the design of environmental field observation framework, but also to the planning of functional zones and biodiversity conservation in a protected area. However, there is a lack of effective methods for landscape edge effect quantification. In this paper, we propose a method for quantitative assessment of landscape edge effects by using the concept of landscape ecology and GIS technique. We also discuss the ecological implications of landscape edge effect quantification.