A PLANT SUCCESSION MODEL RELEVANT TO WEED BIOCONTROL

摘要

Most targets for classical weed biocontrol do not conform to the conventional linear view of plant succession that communities are driven between a pioneer and climax state by removing or imposing disturbance and stress. This leads to disagreements whether a weed is a suitable target for biocontrol. The alternative Astates and transitions@ model provides a rationale for weed biocontrol. Herbaceous annuals, biennials and perennials that form stable states are all amenable to weed biocontrol, but for transitional species the likelihood of success decreases with the brevity of the transitional period. Thus the theory provides a means of assessing a target weed in terms of ease of control success and the difficulty with short-term transitional weeds suggests some of the agent attributes needed.