REDUNDANCY STRUCTURE IN PHYTOCOENOSIUMS AS AN EXPLANATION OF ECOSYSTEM STABILITY
植物群落的冗余结构——对生态系统稳定性的一种解释

The mechanism of phytocoenosium stability could be interpreted with the redundancy theory.Redundancies of a phytocoenosium consist of organ redundancy in a plant,redundancy of genetic structure(or individuals)in a population,and species redundancy and layer redundancy at community level.These redundancies maintain relative stability of phytocoenosium.The resistance of phytocoenosium to perturbation derives from species redundancy in a phytocoenosium and redundancy of genetic structure in a population,but resilience from layer redundancy and organ redundancy of individuals.The redundancy structure decides whether a phytocoenosium is resistant or resilient,or both resistant and resilient.This study shows that the redundancy theory is more reasonable than diversity begets stability in explaining the stability of both complex and simple phytocoenosiumes. By the property of the compositions,all redundancies in a phytocoenosium are distinguished into quality redundancy and quantityone.Phytocoenosium and population use quanlity redundancy as resistant to perturbation,the organ or clone populations use quantity redundancy as maintaining numberous constance.A role which redundancies play in a phytocoenosium depends on the stand by property.A structure stand by of the phytocoenosium is divided into three kinds:hot stand by,warm stand by and cool stand by.The hot stand by is all species in each layer and individuals in a population, layers other than the upper layer is warm stand by,and dormant and adventitious buds is cool stand by.When a phytocoenosium is disrupted by a perturbation,hot stand by will be used for resisting to perturbations,cool stand by for replacement of damaged organ of individuals,and warm stand by for both resisting to perturbations and selfrepairing of damaged parts of a phytocoenosium.