Author
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Bryson, Charles |
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Submitted to: Meeting Abstract
Publication Type: Abstract Only Publication Acceptance Date: 7/10/2003 Publication Date: 11/3/2003 Citation: Bryson, C.T. 2003. Biology of pathways for invasive weeds. [Proceedings] Invasive Plants in Natural Managed Systems: Linking Science and Policy - 7th International Conference on the Ecology and Management of Alien Plant Invasions. 7:13-14. Interpretive Summary: Technical Abstract: Botanists, Ecologists, and Weed Scientists have long been aware of the problem of non-native weed species that are already established in the U.S. and have gleaned some knowledge of how some of the more important weeds reproduce, spread, and interact with native and acceptable non-native species. Scientists agree that it is a necessity to control further introductions and invasions of plant species that have the potential to become serious pests of agriculture, forest, urban, and natural areas. Understanding the basic biology and ecology of weeds is extremely important to determine pathways of entry, spread, establishment, and persistence. Dispersal of sexual or asexual propagules varies among plant species. Usually humankind is directly or indirectly responsible for most introductions, whether intentional or unintentional. The most common pathways of movement of weeds include: contaminated soil, food, feed, fiber, ballast, and packing and bagging material. However, pathways for introduction and spread may be from ornamentals, forages, or plants used for erosion control that were once thought to be acceptable, but have become weedy. Weed seed may remain viable following passage through digestive tracts of mammals and birds, or may become attached to fur or feathers. Tropical soda apple spread in the U.S. is a prime example of weed dispersal via the digestive tract of domesticated animals over long distances and within smaller areas by wildlife. Non-native weeds may also spread during natural mammal and bird migrations. Although it is impossible to prevent movement of weed propagules during migrations, flooding, and windstorms, effective weed control or suppression can reduce the potential spread of weeds. Once established in an area, weed seeds may remain viable in seed banks for many years. For example, Johnsongrass and other weed seeds may remain viable for more than 15 yr in soil. Cogongrass and other perennials can be dispersed as wind blown seeds or as rhizome-contaminated soil. The success of a weed's biological pathway is dependent on several factors including the method or mechanism of dispersal, longevity of the propagule, environmental conditions, and competitive and reproductive ability. Sanitation measures can eliminate the biological pathway for dispersal and prevent the spread of weeds. Practices such as cleaning vehicles, equipment, animals, or maintaining cattle in weed-free areas before moving them to another site can prevent the dispersal, establishment, and persistence of weed seeds and/or rhizomes in previously weed-free areas. |
