Inventory and Survey Methods for Nonindigenous Plant Species (PDF)

Chapter 9 • Coarse-Scale Mapping: The Section or Quadrangle-based Methodp Figure 2. Interactive map of Dalmatian toadflax (Linaria dalmatica) along the Yellowstone River in Park County, MT, createdby querying the NRIS Digital Atlas of Montana. The website for this interactive database is http://maps2.nris.state.mt.us/mapper/index.html.Users choose a search option (i.e., county), click on the “Land Information” tab, then choose which NIS to displayfrom the “Section-based Weed Distribution” category.to the application can update the database as they acquirenew spatial information on the presence or absence of NISper section. NRIS serves section-based maps on the Internetthrough their Digital Atlas of Montana (http://map2.nris.state.mt.us/mapper/index.html). Any interested user canquery the atlas and build maps depicting NIS infestationsusing several search options, including counties, Indianreservations, national forests, towns, rivers, and highways(Figure 2). These section-based NIS maps can be made atany scale and laid over other map layers (e.g., topography,land ownership), printed from the Web interface, andimported into ArcView (ESRI Inc.) if desired.In 2002, the Colorado Department of Agriculture,Colorado State University, the USDA Forest Service, andthe Bureau of Land Management developed a statewidemapping program utilizing the quarter-quadrangle grid. Aquarter-quadrangle is one quarter of a standard 1:24,000USGS 7.5-minute topographic quadrangle. Twenty speciesof noxious weeds were mapped across Colorado by thismethodology to determine statewide distribution andabundance. In addition, two species, leafy spurge and yellowstarthistle (Centaurea solstitialis), were mapped across thewestern region through the Western Weed CoordinatingCommittee, utilizing the same methodology. In 2004 theColorado Department of Agriculture remapped severalspecies and mapped one new species, absinth wormwood(Artemisia absinthium), using the quarter-quad methodology.The success of quarter-quadrangle mapping relies onthe knowledge of county weed managers and other weedmanagement professionals from state and federal land managementagencies. Acreage data are solicited periodically foridentified species of concern, typically state noxious weedstargeted for coordinated statewide management. A formalrequest is sent out to county weed supervisors requesting67Inventory and Survey Methods for Nonindigenous Plant Species