Methodology and Interpretation
Percent forest within 600 meters of wetlands
The amount of forest land cover within 600 meters of wetlands may indicate the
amount of upland wooded habitat for organisms that depend on upland forest for
travel (unimpeded by other land cover types, such as agricultural land or urban
areas) to and from wetland areas for breeding, water, forage, or shelter over
relatively long distances. Thus, this metric is calculated by summing the total
number of forest land cover cells within a twenty cell buffer (600 meters) from
wetlands land cover cells in the reporting unit and dividing by the wetland total
area within the reporting unit. Cells inside the buffer zone but outside of the
reporting unit boundary are ignored. Other buffer distances may be more
appropriate for habitat analyses, depending on the type of organism.
Quantile: Each class contains an approximately equal number (count) of features. A quantile
classification is well-suited to linearly distributed data. Because features are grouped by the number
within each class, the resulting map can be misleading, in that similar features can be separated into
adjacent classes, or features with widely different values can be lumped into the same class. This
distortion can be minimized by increasing the number of classes.
Metric input GIS data:
- United States Hydrologic Units (8-digit HUCs) - Metadata
- United States Coastal Change Analysis Program (CCAP) - Metadata
|