Development and Evaluation of Ecosystem Indicators for Urbanizing Midwestern WatershedsEPA Grant Number: R825871
Title: Development and Evaluation of Ecosystem Indicators for Urbanizing Midwestern Watersheds
Investigators: Spacie, Anne , Engel, Bernard A. , Harbor, Jonathan M. , Hondzo, Midhat
Institution: Purdue University
EPA Project Officer: Hahn, Intaek
Project Period: October 1, 1997 through September 30, 2000
Project Amount: $672,323
RFA: Ecosystem Indicators (1997) RFA Text | Recipients Lists
Research Category: Ecological Indicators/Assessment/Restoration , Ecosystems
Urban areas are spreading over much of the eastern United States, and yet our understanding of their impact on ecosystem processes is very poor. Understanding and managing the responses of these systems to urbanization requires a multi-disciplinary effort ranging from site-specific to large-scale regional studies. The emergence of usable ecosystem indicators is particularly important in this context as it allows for the development of practical management approaches in the absence of detailed monitoring of the complete system. However, while urbanization usually has negative impacts on stream ecosystems, the causal relationships have not been well studied. Simple empirical indicators may actually be misleading if they are not grounded in an objective understanding of the links between the indicator and the system variables we are trying to preserve. The focus of this project is on the development of predictive indicators of urbanization that are applicable to midwestern watersheds and stream ecosystems, and more importantly to illustrate an objective methodology for developing and testing ecosystem indicators.
Objectives:1) To quantify the impacts of urbanization on hydrologic regimes, water quality, and habitat structure of stream ecosystems using paired experimental watersheds, and to develop linked models that accurately predict these impacts; 2) To use the linked models developed in the first objective as a virtual laboratory within which to generate and test indicators of urbanization and hydrologic change in terms of responses of fish and macroinvertebrate communities; and 3) To use these models and indicators to assess the response of stream communities to alternative urbanization scenarios with extension to larger watersheds in the region.
The proposed research will examine watersheds in transition from rural to urban. The initial study site is a 216 km2 set of paired experimental watersheds encompassing two adjacent third-order streams. The watersheds typify drainages in the cornbelt ecoregions; however one is urbanizing more rapidly than the other, with substantial new housing developments planned in the next few years. Stream flow, water quality, and aquatic biota have been intensively monitored since 1991, allowing the interpretation of temporal trends, and a detailed geographic information system (GIS) data base is available for spatial analysis. The research approach is to establish linked process models that address the impact of land use change on the physical and chemical characteristics of runoff, that route this runoff through the stream system to assess flow, water quality, and habitat quality, and which then link changes in stream variables to changes in aquatic community structure. A set of environmental indicators will be generated and tested based on these relationships. The predictive relationships among indicators will then be evaluated for a range of larger and more urbanized watersheds in the region. Thus, the project will provide an opportunity to examine indicator behavior over a wide range of scales and physical settings under alternate urbanization scenarios.