The Indicator
The indicator would report separately on the biological community condition
of (1) the combined area of land, lakes, and coastal waters and (2) linear
features (streams and coastlines). Community condition would first be
broken into two major categories: lands and waters under intensive human
use and those that are left in semi-natural-to-natural condition. Intensive
human use would be divided further into two categories: physically altered
and highly managed. Semi-natural-to-natural lands and waters would be
divided further into three categories: disturbed, less disturbed, and
undisturbed.
Examples of system-specific components and indications of the possible
data sources that might be used for reporting on each category follow.
Physically Altered Communities
- Areas covered by 30% or more constructed materials (e.g., asphalt,
concrete, buildings), as measured from satellites. Data are available
from the National Land Cover Dataset (NLCD; 30-m resolution. These
data are derived from the Multi-Resolution Land Characterization
Consortium, which is a partnership between the U.S. Geological
Survey, the USDA Forest Service, the National Oceanographic and
Atmospheric Administration (NOAA), and the Environmental Protection
Agency (see the technical note for
the national extent indicator for more details).
- Open mines, quarries, and gravel pits, measured from satellite. Data
also available from the NLCD.
- Area of road surface (including unpaved roads). Data from the Federal
Highway Administration, U.S. Department of Transportation, Highway Statistics
1999, http://www.fhwa.dot.gov/ohim/hs99/.
- Lined and culverted streams. Data not available.
- Hardened coastline miles. Partial data available from NOAA’s
Environmental Sensitivity Index atlases. (See Shoreline
Types.)
Highly Managed Communities
- Cropped land (not including interspersed natural area), as measured
from satellites. Data from the NLCD.
- Forests planted with nursery stock. Data from Forest Service; see
the forest management categories, page 119.
- Intensively grazed grassland. Data not available; also, no specific
threshold has been identified that would be used to define which lands
are intensively grazed.
- Stream miles impounded into lakes. Data not available.
- Drained or impounded wetlands (areas that remain wetlands but have
been highly altered). Data not available.
Disturbed Semi-Natural Communities
- Forests heavily affected by invasive species. Data not available.
- Grasslands and shrublands heavily affected by invasives. Data not
available.
- Coastal area heavily affected by invasive species. Data available
only for selected estuaries (see the
technical note for coasts and oceans non-native species).
- Freshwater rivers and streams with low IBI (Index of Biological
Integrity, a species-based measure of disturbance). Data not available.
See the
technical note for the condition of bottom dwelling animals.
- Lands and waters with highly altered species mix, such as would be
characteristic of altered fire or hydrologic regimes. Neither data nor
methods are currently available.
Less Disturbed
- Semi-natural lands and waters that are neither clearly disturbed nor
identified as undisturbed.
Undisturbed
- Biological communities with species mix essentially the same as would
occur without man’s influence. There is no generally accepted method
to identify such lands and waters.
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