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The invasive plant Mikania micrantha H.B.K.,which is native to central and south America,has caused serious damages in southern China,especially in secondary forest.The invasive plant is a fast growing herbaceous vine.Under favorable sunlight and moisture,it can easily climb up,spread on top of other plants,and form a thick cover that intercepts light and adds heavy load to the underneath plants.It possesses strong asexual propagation ability and has many branches that easily produce adventitious roots so that a stem fragment can grow into a new independent individual.In addition,it has huge amounts of tiny and easily wind-dispersed seeds as well as a high germination rate.Damage of primary vegetation is the prerequisite of invasion.This work critically evaluated the control methods and strategies that have been developed and adopted in the past ten years to provide scientific evidences for controlling the invasive plant. Several controlling methods have been used in field and each method has its own advantages and limitations.Physical removal through cutting stems and digging roots is suitable for small areas with proper caring but not for large area.Removal should avoid fruiting period or fragment dropping because they may promote unintentional anthropologic dispersal.Chemical herbicides can be used when immediate outcome is needed,especially to interrupt fruiting,to clear the area for planting tree,and to foster young.It should be cautious that spraying herbicides may pose negative impact on environment;furthermore,it does not change the habitat,and thus,the invasive plant may re-invade after a few years of no proper action followed.Cuscuta campestris,a dodder,is a safe controlling agent and can easily parasitize the invasive plant.The application of dodder is suitable to mildly control the invasive plant or at an area where physical removal or chemical control are not appropriate.The proliferation of dodder is always behind that of invasive plant;manual dispersal of dodder to timely grow and disperse is needed.Community restructuring can suppress the invasive plant permanently.The restructuring creates an environment unsuitable for the invasive plant but proper for some fast growing tree species.Community restructuring is particularly suitable for afforestation area,but it costs more than other methods in short term.Natural enemies control and allelopathic control are promising while most are still at the exploratory stage.In future,more attention should be focused on the exploration of effective natural enemies,the integration of controlling methods,and the revelation of distribution pattern in macro level. The correct strategy to control the invasive plant is as follows: persistency rather than fast result for controlling vast area invasion;prevention of invasion to new areas being utmost important;revision of existing evaluation system to direct controlling from cleaning invaded area to protecting un-invaded area;management priority being addressed on mild invasion area and area that potentially becomes the source of dispersal to surrounding and distance area,spend less control resources to areas that have been severely invaded and to remote isolated area that have few human activities;establishing demonstration plot to promote knowledge of correct controlling methods and strategy,to enhance public awareness and to improve public confidence on successful prevention and control of the invasive species. |
