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published in the 2002 State of the Nation’s Ecosystems Report as well as the 2003 and 2005 Web-Only Updates have been superseded by the 2008 Report and thus should be used with caution.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.

What Is This Indicator, and Why Is It Important? This indicator would report, for areas where croplands account for a large percentage of the land cover, how much of the remaining vegetation (outside of croplands) is native to the area.

Where croplands dominate the landscape, wildlife rely more heavily on the remaining areas for their habitat needs. Since vegetation dominated by non-native species often has much lower value as wildlife habitat, a high proportion of non-native plant species in the remaining non-cropland areas will have a harmful effect on wildlife populations. For example, when lands in the Conservation Reserve Program, which provides rental payments to farmers who retire lands important for conservation, are converted from non-native grasses to native prairie grass, upland bird populations increase significantly.

Why Can't This Indicator Be Reported at This Time? Several questions must be answered before this indicator can be implemented. These include the scale at which it should be reported (i.e., county, state, or region?); the threshold for including an area in the indicator (i.e., should the indicator include only areas with more than 50% croplands, or more than 75%?); and the proportion of non-native species that should be used to categorize areas as “dominated” by non-native rather than native species.

Once the indicator is clearly defined, obtaining data may also be difficult. The fraction of land in a county, state, or region that is cropland, and its location, are readily available from satellite data. Whether vegetation is dominated by native or non-native species cannot generally be determined using satellite imagery, but many state and federal agencies, nongovernmental organizations, and universities collect data on non-native plants. However, these data have never been brought together to provide consistent information over large areas. Many existing federal, state, and local government programs could contribute to reporting on the extent of non-native species, as could nongovernmental organizations and academic institutions.