Largest Patch Index

The Indicator

This is an indicator of the degree of forest fragmentation in a watershed. As noted elsewhere, large forest blocks are becoming increasingly rare, and therefore valuable, in Maryland. The index is a measure of the percentage of a watershed’s forest that is contained in the largest patch of forest in that watershed—it is equal to the area of the largest forest patch divided by the land area of the entire watershed.

Forest cover is from the National Land Cover Data set (NLCD).

Indicator Use

Watersheds with larger values for this index are more likely to support an array of important ecological functions associated with forest; they are also more likely to support forestry activities. Even a relatively small change in use from forestry to agriculture or urban type development, depending upon its location, could result in a substantial reduction in the value for this indicator.

Ecological Assessment | Criterion 1 | Data & Indicators | Home