Mean Nearest Neighbor
This indicator of forest fragmentation is related to the ability of species to move from forest patch to forest patch, particularly important in the event of a local extinction of some species that can only be overcome by recolonization from a nearby patch. The further a forest patch is from another forest patch, the more likely such an extinction will occur and the more difficult recolonization will be.
To create this indicator, edge-to-edge distances were calculated between all forest patches and their nearest neighboring forest patch; these distances were summed and the sum divided by the total number of forest patches in the watershed. Forest cover is from the National Land Cover Data set (NLCD).
The influence of agriculture on this indicator is evident in the distribution of values shown on the map. Restoring connectivity of forests in these watersheds, or at least stepping stones that are closer together, could be an objective of forest and watershed management in these areas.