SS3.07 Headwater Ecosystems in Forested Landscapes and Beyond
Date: Wednesday, June 12, 2002
Time: 11:15:00 AM
Location: View Royal
 
KilhamSS, Drexel University, Philadelphia, PA, USA, kilhams@drexel.edu
Steffy, L, Y, Drexel University, Philadelphia, PA, USA, Luanne.Yvonne.Steffy@drexel.edu
 
RESPONSE OF BIOTA TO URBANIZATION IN A WATERSHED IN THE PHILADELPHIA, PA AREA
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Valley Creek is an urbanized watershed near Philadelphia and is a Pennsylvania Exceptional Value Stream. Urbanization is most pronounced in the headwaters and decreases downstream toward Valley Forge National Historical Park. Valley Creek has two main stems in a spring fed, fractured karstic basin. Its historical record spans 300 years and now has 17% impervious surface and numerous toxic waste sites. Fifteen stations were sampled on a seasonal basis (since Fall 2000) both upstream and downstream of contaminant sources. Community structure was evaluated using species, C:N:P ratios and stable isotopes. Nitrogen isotopes in the food web were elevated in the watershed, and particularly near housing developments in the Valley Creek branch. C:N ratios were more elevated in Valley Creek than Little CValley Creek. Diversity of fish also responded to land use parameters.