Pennslyvania Natural Heritage Program
Tuscarora Creek

Watershed Conservation Prioritization

We highlighted unique riverine conditions that designate certain watersheds to be of greater conservation concern than others by combining data from many parts of the Aquatic Community Classification (ACC). Information was included from the biological classification, fish and macroinvertebrate biological metric scores, and results from our least-disturbed stream (LDS) reach analysis.

The ACC biological community information provides a qualitative way to examine watersheds based on biological assemblages and the various stream habitat types that occur within it. We performed this analysis with only communities that indicate quality habitat conditions, which allowed us to select stream reaches with relatively unaltered habitat condition. See chapters 4 through 7 of the ACC User’s Manual for more information about community groups, their respective habitat types and the water quality conditions in which they are found.

Biological metric calculations provide a way to quantitatively rank streams and watersheds related to habitat and water quality and how closely the biotic assemblages reflect natural ecological function. Both fish and macroinvertebrate data were used for metric scores in this analysis. These metric calculations are similar to those used in Indices of Biotic Integrity (IBI), which are commonly used to synthesize data about water quality and biological diversity.

The results of the LDS analysis were used here to select watersheds that contained the greatest number of relatively undisturbed stream reaches in the study area. By using the LDS results in this conservation prioritization analysis, we are able to include qualitative data based solely on abiotic characteristics of stream reaches in both local and total upstream catchment areas.

For more information on Watershed Conservation Priorities and the data used to select them, see Chapter 10 of the ACC User’s Manual.