Methodology and Interpretation

Percent grassland within 600 meters of wetlands
The amount of grassland within 600 meters of wetlands may indicate the amount of upland herbaceous plant habitat for organisms that depend on upland grassland for travel (unimpeded by other land cover types, such as agricultural land or urban areas) to and from wetlands for breeding, water, forage, or shelter over relatively long distances. Thus, this metric is calculated by summing the total number of grassland 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.

Natural Breaks: Classes are based on natural groupings of data values. Natural break points are identified by looking for groupings and patterns inherent in the data. The features are divided into classes whose boundaries are set where there are relatively large jumps in the distribution of data values.

Metric input GIS data:

• United States Hydrologic Units (8-digit HUCs) - Metadata

• United States Coastal Change Analysis Program (CCAP) - Metadata