Abstract
ArcGIS Modeling Weed Risk on Landscapes in Oregon Track: Ecology and Conservation Author(s): Douglas Johnson, Adele Johnson, Mack Barrington, Mounir Louhaichi Weeds are invading native plant communities across the United States, and many are expanding their range by occupying new habitats. These changes can be mapped, and areas susceptible to invasion can be predicted. We were interested in developing maps of Oregon that would indicate which locations are likely to be invaded by specific noxious weeds. We combined information on the known infestation sites of four noxious weed species with climatic, topographic, and soil information. Data included mean monthly and annual precipitation, temperature extremes, wet days, growing degree-days base 10ºC (50ºF), dates between freezing temperatures, elevation, and soil classification. All data sets were structured to 1.25 arc-minute resolution (3.86 km2). The range of environmental conditions under which each of the weeds grew was determined by extracting from GIS data layers. We then found all areas of the state with similar environments, elevations, and soils indicating areas where invasion is likely. Douglas Johnson Oregon State University Department of Rangeland Resources 302 Strand Ag Hall Corvallis , OR 97331-2218 US Phone: 541-737-1624 Fax: 541-737-0504 E-mail: douglas.e.johnson@oregonstate.edu Adele Johnson Oregon State University Geosciences Wilkinson Hall Corvallis , OR 97331 US Phone: 541-737-1201 E-mail: Adele.Johnson@geo.oregonstate.edu Mack Barrington Oregon Department of Agriculture Natural Resources Division 635 Capitol Street NE Salem , OR 97310 US Phone: 503-986-4715 E-mail: mbarring@oda.state.or.us Mounir Louhaichi Oregon State University Rangeland Resources 202 Strand Ag Hall Corvallis , OR 97331-2218 US Phone: 541-737-1620 Fax: 541-737-0504 E-mail: mounir.louhaichi@oregonstate.edu |
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