受损生态系统类型及影响其退化的关键因素

受损生态系统的退化是当前面临的一个全球性问题，对受损生态系统类型的确认有助于了解其退化机制，进而采取适当的修复和恢复措施。根据受损生态系统的表现可将其划分为3种类型，即结构受损类型、景观受损类型以及混合类型。在结构受损的生态系统类型中，重要物种(如关键种、建群种)的丧失以及种间关系的解构可能在退化过程中起重要作用，因此，关键种、建群种的恢复和保护对于生态恢复是十分关键的。边缘效应、岛屿效应、小种群效应(如Allee效应、近交、遗传漂变)等的强化则可能是导致景观受损类型的生态系统退化的主要因素，因此，针对这种受损生态系统，增加生态系统面积、 降低空间隔离程度、建立片断生态系统间的连接是需要关注的主要问题。

TYPES OF DAMAGED ECOSYSTEMS AND THE CRITICAL FACTORS LEADING TO DEGRADATION

Degradation of damaged ecosystems is a global issue. Identifying the types of damaged ecosystems helps understanding their degradation mechanisms, and furthermore, restoring them with appropriate approaches. Based on the common characteristics after damage, the damaged ecosystems are classified into three types, i.e. structure-damaged, landscape-damaged and mixed types. Structure-damaged and landscape-damaged ecosystems suffer from different effects. Loss of important species (such as keystone species, edificators of communities) and destruction of species relationship play important roles in the degradation of structure-damaged ecosystems. Therefore, conservation and recovery of these species is the key task to restore structure-damaged ecosystems. However, edge effect, island effect and small population effects (such as Allee effect, inbreeding and genetic drift) may play critical roles in the degradation of landscape-damaged ecosystems. To restore such ecosystems, it is important to increase area of fragments, decreas e distance isolation and make links among fragments.