Note that the data published in the 2002 State of the Nation’s Ecosystems Report as well as the 2003 and 2005 Web-Only Updates have been superseded by the 2008 Report and thus should be used with caution. For the most recent data, purchase the 2008 Report from Island Press.

The Data Gap

Data from various sources must be evaluated and synthesized to provide regional and national estimates of the area occupied by non-native plant species. There are numerous federal, state, and local government programs that collect relevant information, plus important efforts in nongovernmental organizations and academic institutions that could contribute to reporting on this indicator.

A recently established consortium includes representatives from the U.S. Geological Survey, the U.S. Fish and Wildlife Service, National Aeronautics and Space Administration, USDA Forest Service, The Nature Conservancy, Colorado Natural Heritage Program, USDA Animal Plant and Health Inspection Service, National Park Service, Bureau of Land Management, Colorado State University, the Biota of North America program (University of North Carolina), and others. This initiative, titled “One if by Land, Two if by Sea,” will attempt to better coordinate and synthesize existing data on non-native species in the United States. Coordination for this initiative is being provided by Tom Stohlgren, USGS Natural Resources Ecology Laboratory, Colorado State University, Fort Collins, CO 80523, tom_stohlgren@USGS.gov.

Many agencies of the Departments of Interior and Agriculture, as well as state and local governments, nongovernmental organizations, and universities, collect important data on invasive plants in grassland and shrubland regions. Several examples of such programs are listed below.

The USDA Forest Health Monitoring program (http://www.na.fs.fed.us/spfo/fhm/), for example, collects plant cover data in forests throughout the United States, and the program is expanding to include grasslands and shrublands in some areas.

• U.S. Department of Agriculture’s Center for Plant Health Science and Technology, a part of the Animal and Plant Health Inspection Service’s Plant Protection and Quarantine program, maintains the Federal Noxious Weeds Database, which provides descriptive and some distributional data on many recognized invasive plants (see http://www.invasivespecies.org/fedweeds.html). The distribution data for the Federal Noxious Weeds Database (which provides data up to 1999) are from the Synthesis of the North American Flora by John Kartesz (North Carolina Botanical Garden, University of North Carolina) and Christopher Meacham (Jephson Herbarium, University of California, Berkeley). The Synthesis is available as an interactive database on CD-ROM (see http://www.bonap.org/synth.html for ordering information). It provides information at state level, although the program from which it was generated also maintains county-level data for 44 states (see www.bonap.org/summary.html).
• The University of Montana maintains the INVADERS database, which covers five northwestern states (Oregon, Wyoming, Montana, Idaho, and Washington) with information at county level. INVADERS may be accessed at http://invader.dbs.umt.edu/.
• The U.S. Geological Survey has initiated the Southwest Exotic Plant Mapping Program, or SWEMP, which is designed to develop a regional database of exotic plant distributions for the Southwest (Arizona, New Mexico, and Colorado Plateau portions of Utah and Colorado). Some data are available at http://www.usgs.nau.edu/SWEPIC/. Standardized field techniques should be adopted to create comparable data that can be synthesized. These extensive field datasets must be linked to high-resolution maps of vegetation, soils, topography, and land use to achieve reliable national coverage.