The relationship between riparian areas and biological diversity A comparison of streams in eastern Colorado and southwestern Virginia By Ann Widmer

EPA’s need for monitoring… EPA Administrator William Reilly (1989)— “Good News– Based on my years in the environmental movement, I think the Agency does an exemplary job of protecting the nation’s public health and quality of the environment. Bad news– I can’t prove it.”

(environmental monitoring and assessment program) Key components: statistical design wide-scale application across the country use of biological indicators

What is an indicator? An instrument for monitoring the operation or condition of a physical system »Webster’s II New Riverside University Dictionary

EMAP Measurements Fish assemblage Benthic macroinvertebrates Periphyton Water quality Habitat parameters –Substrates –Embeddedness –Riparian vegetation Plecoptera (stonefly) Periphyton on river rocks

Do indicators work? (Are they a good measure of ecological health?)

2 healthy aquatic systems Completely different stream character.

My project EMAP sampling in Colorado –Concerns –Qualitative data Comparison of trends to those in southwest Virginia –Development of indicies –Intensively studied area

Trends in southwest Virginia 1. As riparian vegetation is decreased, fish and mussel species diversity is decreased Diamond, J.M., and V.B. Serveiss Identifying sources of stress to native aquatic fauna using a watershed ecological risk assessment framework. Environmental Science Technology 35:

Trends in southwest Virginia 2. As riparian vegetation is decreased, benthic macroinvertebrate density is decreased. Effect more pronounced very locally (within 200 meters) Sponseller, R.A., E.F. Benfield, and H.M. Valett Relationships between land use, spatial scale, and stream macroinvertebrate communities. Freshwater Biology 46:

Colorado streams (variation with elevation) Above timberline

Colorado streams (variation with elevation) Forested mountain

Colorado streams (variation with elevation) Urban– Front Range

Colorado streams (variation with elevation) Plains

Contrary trends? Above timberline Forested mountain Urban– Front Range Plains Riparian vegetation (relative to stream size) 1432 Macro- invertebrate diversity 1432 Fish species diversity 1234

Additional considerations… Scale –Virginia studies were in a small watershed –Colorado study encompasses half a state– compare within similar conditions Sedimentation Land use and fish stocking Water quality

Comparison of similar streams Bear Creek, CO Boulder Creek, CO Clear Creek, CO –Found the highest fish species diversity and density in the Bear Creek, the one with the most riparian vegetation

Recommendations to the EPA Indicators should not be used to compare health of dissimilar streams –Different states – big difference in riparian size –Different elevation –Different stream order Indicators most useful when comparing the same site over time– environmental monitoring