Methodology and Interpretation

Percent forest adjacent to wetlands
The amount of forest land cover on the periphery of wetlands may indicate the amount of upland wooded habitat for organisms that might travel relatively short distances to and from nearby forested areas and wetland areas for breeding, water, forage, or shelter. Also, the affect of runoff on wetlands from areas nearby (e.g., agricultural land) may be ameliorated by biogeochemical processes that occur in forests that are on the periphery of the wetland. Thus, the percentage of forest land cover directly adjacent to wetlands is calculated, by summing the total number of forest land cover cells directly adjacent to wetland land cover cells in the reporting unit and dividing by wetland total area in the reporting unit. Cells outside buffer zones for wetlands within each reporting unit are ignored. Other buffer distances may be more appropriate for habitat analyses, depending on the type of organism; for runoff analyses the chemical constituent(s), flow dynamics, soil conditions, position of wetland in the landscape, and other landscape characteristics should be carefully considered.

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