VDCR Invasiveness Ranking-

The Virginia Department of Conservation and Recreation has compiled a list of Invasive Alien Plant Species known to occur in Virginia.  For each of the plant species, an invasiveness ranking is assigned that assesses:    

            -the ability of the species to impact natural landscapes as well as other species

            -the capacity of the species to disperse and invade natural environments

            -the distribution and abundance of the species

            -the difficulty with control and management of the species 

Based on its perceived threat, exotic species may be classified as highly invasive, moderately invasive, or occasionally invasive.

   Highly Invasive Species have the most detrimental effects on natural areas and native plant species.  By aggressively invading ecosystems, they disrupt essential processes, as well as community composition and structure by quickly establishing and spreading viable populations.

    •Moderately Invasive Species are only somewhat disruptive to native ecosystems and their plant communities, affecting some species without threatening all.  These plant species generally require a minor disturbance for a population to establish, but may spread quite readily once present.

    •Occasionally Invasive Species generally do not disrupt whole ecosystems, but may threaten some native plant communities by out-competing native species for essential resources.  They generally establish populations in severely disturbed areas and spread slowly.