Is Housing a Factor in the Distribution of Invasive (Aggressive, Nonnative) Plants?
Exotic plant invasions cause extensive damage in many ecosystems. Therefore, we need to understand how human activities and other factors help introduce and spread exotic plants. Housing development is particularly important because disturbed habitats are more easily invaded, landscaping introduces exotic plants, and roads are pathways of potential spread. Between 1950 and 2000, the proportion of urban area in the continental U.S. doubled, while rural low-density housing increased fivefold.
We analyzed the relationship between housing and distribution of invasive exotic plants in forested areas at coarse and fine scales. Specifically, we tested the influence of housing compared with other environmental and human factors in explaining exotic invasive plant distribution.
At a coarse scale, we looked at New England using three sets of variables at the county level: housing, other human influences, and environmental factors. At a fine scale, we analyzed 80 field plots in Baraboo Hills, 30 miles north of Madison, Wisconsin. On each Baraboo Hills plot, we noted the presence/absence of eight common invasive exotic plants: garlic mustard (Alliaria petiolata), Japanese barberry (Berberis thunbergii), autumn olive (Elaeagnus umbellate), bell’s honeysuckle (Lonicera x bella), white mulberry (Morus alba), common buckthorn (Rhamnus cathartica), multiflora rose (Rosa multiflora), and bittersweet nightshade (Solanum dulcamara).
At both the broad and fine scales, we found that housing, roads, forest cover, forest fragmentation, and topography were related to the distribution of invasive exotic plants. More significantly, housing variables were as important as other human-related or environmental variables in determining the presence and diversity of invasive exotic species at both scales.
Our results have clear management and conservation implications. Housing is expected to continue growing, particularly in rural and natural areas. Areas undergoing housing development put nearby natural habitat of high conservation value at risk for exotic plant invasions. Also, areas with new and existing housing are an appropriate main target for invasive plant monitoring programs. Regulations that focus on exotic species used for gardening or landscaping near natural areas may be particularly effective.
Gavier, Gregorio; Stewart, Susan; Huebner, Cynthia D.; Radeloff, Volker C. 2009. Is housing a factor of invasive plants distribution at coarse and fine scales? In: McManus, K.A.; Gottschalk, K.W., eds. Proceedings. 19th U.S. Department of Agriculture Interagency Research Forum on Invasive Species, 2008. Gen. Tech. Rep. NRS-P-36. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station: 27-29.
- Gregorio Gavier, Department of Forest and Wildlife Ecology, University of Wisconsin
- Susan Stewart, Research Social Scientist, U.S. Forest Service, Northern Research Station
- Cynthia D. Huebner, Research Botanist, U.S. Forest Service, Northern Research Station
- Volker C. Radeloff, Department of Forest and Wildlife Ecology, University of Wisconsin
Last Modified: 10/20/2010