• Study sites will be selected along stressor gradients within each class in the classification 
framework, to determine if stressor-response relationships vary among these classes. 
• Stressor gradients will be defined by land-cover/land-use attributes in order to provide the 
opportunity to develop simple diagnostic indicators of impairment at the watershed scale. 
• Gradients representing multiple stressors will be used to test multivariate methods in 
order to allocate variation in biological community composition to different 
environmental gradients or stressors. 
• Model development will incorporate both single stressor-response relationships and 
multiple stressor interactions to enhance forecasting of potential future impacts or 
recovery based on future scenarios. 
7. Great Lakes Coastal Watersheds/Wetlands/Nearshore Zones. 
Magnitude of watershed loadings and the relative sensitivities of instream and coastal ecosystems 
will be predicted and assessed through the application of watershed and coastal wetland 
classification schemes in the Lake Michigan basin. A watershed classification scheme based on 
hydrologic thresholds of response to forest fragmentation and watershed storage already has been 
tested for small coastal watersheds surrounding the western arm of Lake Superior across two 
distinct hydrogeomorphic regions (Detenbeck et al. 2000). This classification scheme is being 
extended to other regions with different single land-use gradients, and to watersheds with mixed 
land-use gradients (Simon 1999, Cincotta 2000). Through collaboration on a West Virginia 
REMAP project, watershed classification schemes are being developed for a region with 
mountainous terrain, and consider land-use gradients related to agriculture, urban and residential 
development, and mining. Through collaboration on a Great Lakes coastal wetlands REMAP 
project, watershed classification strategies are being developed for watersheds spanning a range 
of sizes (1 to 450 ha) and a mixture of land-uses. In addition, MED scientists have assessed 
differences in nutrient dynamics among hydrogeomorphic types of coastal wetlands, based on 
expected differences in retention time and relative influence of riverine versus lacustrine inputs. 
This approach will be extended to evaluate impacts from suspended and bedded sediment 
loading. For toxic chemicals, methodologies will be developed for predicting the parameters and 
variables which affect the bioavailability of the chemicals for the different levels of the 
classification schemes. 
MED will continue to develop a series of empirical stressor-response relationships in the Great 
Lakes basin for stressors known to constrain community composition for specific combinations 
of taxa and aquatic resource classes: a) temperature, flow, and clean sediments for instream fish 
communities; b) suspended and bedded sediments and flow for macroinvertebrate communities; 
c) flow, suspended and bedded sediments and nutrients for periphyton communities; d) nutrients 
and suspended and bedded sediments for coastal wetland vegetation; and e) habitat alteration and 
food-web structure for coastal fish populations and communities (Detenbeck et al. 2000). 
Current protocols for development of indices of biotic integrity (IBIs) yield indicators of general 
condition of biological communities for State 305b assessments, but do not yet provide 
155 
