草原群落退化与恢复演替中的植物个体行为分析

定义植物个体小型化是在草原过度放牧条件下 ,草原植物植株变矮 ,叶片变短、变窄 ,节间缩短 ,以及根系分布浅层化等性状的集合。小型化个体的生态学属性介于环境饰变与生态型之间 ,特称之为扰动响应型。个体小型化逆转过程表现出集体行为 ;小型化个体具有维持其形状的保守性 ,变化的阶段性和突变性 ;小型化的逆过程即正常化过程 ,与演替时间有关。个体小型化是过度放牧下群落生产力衰退的重要表现 ,是对过度放牧的负反馈机制。在草原群落退化演替机理研究中 ,对个体小型化的深入认识是十分重要的环节。

ANALYSIS OF THE PLANT INDIVIDUAL BEHAVIOUR DURING THE DEGRADATION AND RESTORING SUCCESSION IN STEPPE COMMUNITY

Plant individual miniaturization resulting from over grazing can be characterized by a suite of morphlogical traits: stunted height, shortened and narrowed leaf blades, shortened internodes, hardness in stems and leaves and roots shallower in the soil profile. In terms of ecological attributes, plant miniaturization belongs to a specific type that lays between an ecotype and a form of environmental modification, and is defined here as a type of disturbance response. Individual miniaturization is the basic cause of decreasing community productivity resulting from over grazing. It is a negative feed back mechanism and an important link in degradation succession mechanisms in grassland communities.