a state of dynamic equilibrium within a community of organisms in which genetic,species and ecosystem diversity remain relatively stable,subject to gradual changes through natural succession.
www.for.gov.bc.ca/hfd/library/documents/glossary/E.htm
an environment that is healthy and fully functional Removing the food supply from a habitat upsets the ecological balance.
www.inhs.uiuc.edu/chf/pub/virtualbird/glossary.html
the fragile arrangement of living things,non-living things,food webs,and environmental conditions that allow for the continued success of an ecosystem.
216.168.47.67/cis-fishnet/Crest/CRD.htm
一共三种,可以任选一种