Biological processes and characteristics are important factors in the introduction, spread, and establishment of invasive weeds. These biological traits include reproduction, dispersal, phenology, physiology, protection from herbivores, tolerance to environmental extremes, and interspecific interactions. Measures and methods to prevent dispersal, establishment, and persistence of nonnative invasive weeds include knowledge of the most vulnerable growth stages, management strategies, maintenance of weed-free areas, and sanitation of vehicles, transportation equipment, animals, and other modes of dispersal.

Additional index words: Dispersal, ecology, invasive weeds, reproduction.