干扰与植被的关系

Relationship between disturbance and vegetation

干扰与植被的关系主要表现在干扰对物种的进化意义和干扰对植被过程的调整作用。在研究干扰和植被的关系时 ,生态学家将干扰进行了抽象和分解。植物种对干扰的适应表现在繁殖、物候、形态、生理等方面。植物特性间的均衡、植物的形态可塑性、植物多样性是植被适应干扰的机制。在分析植被对干扰的适应时 ,生态学家引入了功能类型、对策等概念框架。干扰对植被的作用有正反两个方面。不同的干扰类型、强度、频度、历史具有不同的作用。放牧、火烧、洪水、风沙、刈割和砍伐等干扰方式对植被的正负作用得到了生态学界的广泛重视。针对全球尺度的扰动与植被关系研究是目前扰动生态学研究的核心问题。但是 ,由于生态研究的特殊性 ,很多相关的问题还未被解决。

Effects of disturbance on vegetation can be summarized in two categories: 1) adaptations of species or vegetation to disturbance; and 2) roles of disturbance in determining vegetation processes. In studying the relationship between disturbance and vegetation, ecologists either take all kinds of disturbance as one force responsible for plant adaptations, or divide disturbance into specific disturbing events modifying vegetation processes. The traits associated with disturbance in plant species are in reproduction, phenology, morphology and physiology. The trade-offs between traits, morphological plasticity and ecological diversity are adaptations of plants to disturbance. In exploring the relationship between disturbance and vegetation, such concepts as plant functional types and strategy have been introduced by ecologists. Disturbance has positive and negative effects on vegetation. Differences in types, intensities, frequency and sequence of disturbance may cause differences in effects of disturbance on vegetation. Effects of grazing, firing, flooding, eolian sand mobility and cutting have attracted ecologists' attention extensively. The key issue in studying effects of disturbance on vegetation at present is to probe the relationship between disturbance and vegetation on the global scale. Due to the complexities of ecosystems, however, many relevant questions remain to be answered regarding this issue.