For the past few decades, goats and sheep have been used in the Western U.S. to successfully manage invasive weeds in rangeland, and to reduce the risk of wildfire in urban areas. More recent studies in the Midwest and Northeast have shown prescribed goat grazing to effectively eliminate invasive species such as European buckthorn, Amur honeysuckle, and multiflora rose, and a study at North Carolina State University found goats to be effect at controlling kudzu.
At present, however, there is little specific data supporting the relative effectiveness of prescribed grazing for managing the most common invasive species in the U.S. Southeast. The Chew Crew project thus represents an opportunity for UGA faculty and students to document how various plant species respond to repeated grazing.
Through our sampling event, Botany Blitz, weekly herbaceous collection, and water quality analysis, we can gather data to monitor the goats impact on the invasive plant populations and the environment.
The Chew Crew prescribed grazing experiments have been undertaken on a site where non-native, invasive plants are dominant shrub and ground-layer species. Most of the native species are restricted to tree canopy, and none of the natives is particularly rare or endangered, so we don’t worry about the goats eating native plant species. However, as native plants being to return to the site, we will have to develop strategies to protect valuable native plants from grazing.
We’ve chosen goats as opposed to cattle due to their smaller, lighter build, dietary preferences, aversion to water, and social nature. Goats are more agile and can handle small, steeply sloped sites, such as Tanyard Creek, and prefer a diet of rough, woody plants which makes them well-suited to manage the invasive trees, shrubs, and woody vines that dominate our target areas.
A common concern is that the goats will actually spread the seeds of non-native plants around the site. Although this is a possibility, it is a problem that can be avoided by simply ensuring that grazing does not occur when mature fruits or seeds of the target species are present. Prescribed grazing treatments are generally timed to correspond to periods when the target species are flowering and/or before fruits have matured. This strategy may actually lower the overall contribution of a species to the local seed bank. We noticed that the goats tend to favor tender, new growth which may further reduce the prevalence of seedlings and flowering stems on the site.