The spatial distributions of four plant species native to Asia, yet considered invasive in southwestern Virginia, were studied in order to produce predictive habitat maps. The study took place in the mountains to the north of Blacksburg, VA, on National Forest lands. A random GPS survey of each of the four species, Microstegium vimineum, Lonicera japonica, Rosa multiflora and Elaeagnus umbellate, was used in combination with a series of Geographic Information System (GIS) layers representing environmental variables (Elevation, Aspect, Roads, Trails, Streams, & Normalized Difference Moisture Index) to produce logistic regression models. After field- validating the models, the models were ranked according to usefulness, with the E. umbellate model proving most accurate. It is hoped that such GIS models will allow forest managers to more productively search for invasive species within their jurisdiction, by indicating sites more likely to provide habitat suitable to the invasive species described by the model. A non-GIS search for correlations between the study species' presence and field-collected discrete environmental variables was also included. Both Disturbance and Canopy Cover were considered for their effect upon Microstegium vimineum, Lonicera japonica, Rosa multiflora and Elaeagnus umbellate presence. Using Pearson's Correlation with the Canopy Cover data, and Chi-squared Correlation with the Disturbance data, only R. multiflora and E. umbellate showed significant correlation to decreasing canopy cover. / Master of Science

Invasive species are the second-leading cause of the decline of native species, making it a critical global environmental issue (Pimentel 2005). The goal of this study was to identify which non-native invasive plant species are common in eastern Travis County and which environmental factors associate with their establishment and spread in this area. Five parks and preserves were sampled, as they are intended for the conservation of native species and are more accessible for educational use. Six of the 15 species searched for, Bothriochloa ischaemum, Lactuca serriola, Ligustrum lucidum, Lonicera japonica, Melia azedarach, and Sorghum halepense, were each found in at least one of the five sites. The presences and absences of these species were compared to a suite of ecosystem properties, including habitat, disturbance, the average soil depth, and the horizontal and vertical distances to the nearest pond, lake, stream, or river. None of these six species appears to need observable recent disturbance. All of these six species, both woody and herbaceous, can tolerate shallow soils. The woody invasive species Ligustrum lucidum and Melia azedarach seem to prefer more mesic habitats. The invasive grass species Bothriochloa ischaemum and Sorghum halepense seem to prefer habitats that are more open. Several invasions of potential conservation concern were identified. / text

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