Exotic buckthorn is widespread, and now dominates the woody plant composition, in parts of the Schmeeckle Nature Reserve of central Wisconsin. This Eurasian weed tree is a versatile and aggressive invader that is overwhelming the understory within a diverse array of native plant communities, may be establishing and dispersing itself from various habitat configurations, and appears to exhibit very rapid regeneration in areas where disturbances have recently occurred.
Habitat factors that appear to favor buckthorn include mesic soils, substantial sunlight, thin ground cover, and low abundance of pre-existing native competitors. These conditions often result from disturbances arising from human activities, but may also permit buckthorn to flourish at naturally occurring gaps and edges well away from human disruptions.
Habitat factors that seem to deter buckthorn establishment or dispersal include excessively saturated soils, blockage of sunlight at ground surface by leaf litter or dense foliage, and the dense presence of established native competitors.
Much additional research is necessary if prevention or control of buckthorn is to become effective; at present, it is not. There is need to determine and monitor its spatial extent, to identify its critical physiologic and ecologic limitations, and to assess its environmental, social, and economic impacts. Accurate information of this sort is necessary to raise public awareness to the true magnitude of the problem, and to generate support for control programs, at Schmeeckle Reserve and elsewhere. Experimental application of such information may help improve the results of management response actions in the future.