Citation:

MEHAFFEY, M. H., M. S. NASH, AND A. M. PITCHFORD. MACROINVERTEBRATE RESPONSE TO LAND USE AND STREAM CHEMISTRY IN THE MID-ATLANTIC COASTAL PLAINS. Presented at EPA 2005 Science Forum, Washington, DC, May 16 - 18, 2005.

Impact/Purpose:

The overarching objective is to develop and test landscape indicator statistical models for condition of streams and aquatic biota in relation to pesticides, nutrients, sediments and toxic substances, nationwide. The indicator models will serve as tools for managers who want consistent methods to compare potential impacts on streams within a biophysical region for differing landscape patterns. To accomplish this objective, several sub objectives will be important:

Develop landscape indicator statistical models of stream vulnerability for selected regions of the U.S., beginning with the Mid-Atlantic Coastal Streams; studies in the Midwest, California, and the Southeast will follow.

Demonstrate the application of the landscape indicator models for the ranking of watersheds, the identification of "hot spots," and the evaluation of management options using projected future scenarios of land use for the study areas selected above.

Develop statistical distributions for physical characteristics of small water bodies for use in OPP modeling.

Leverage resources for this research by incorporating existing data into the model development process, and by sharing field study costs with other projects in the same geographic areas.

This task represents a topic area within the Landscape Sciences research program which is described in A National Assessment of Landscape Change and Impacts to Aquatic Resources. A 10-Year Research Strategy for the Landscape Sciences Program, EPA/600/R-00/001. It also supports the Regional Vulnerability Assessment (ReVA) Program.

Besides being responsive to the Office of Pesticide Programs, this research directly supports long-term goals established in ORD's multi-year research plans related to GPRA Goal 2 (Water Quality) and GPRA Goal 8.1.1 (Sound Science/Ecological Research). Relative to the GPRA Goal 2 multi-year plan, this research will "provide tools to assess and diagnose impairment in aquatic systems and the sources of associated stressors" and "provide the tools to restore and protect aquatic ecosystems and to forecast the ecological, economic, and human health outcomes of alternative solutions" (Long Term Research Goals 2 and 3). Relative to the Goal 8 multi-year plan, this research will develop and demonstrate methods to provide states, tribes, and federal, state and local managers with abilities to: (1) assess the condition of waterbodies in a scientifically-defensible and representative way, while allowing for aggregation and assessment of trends at multiple scales; (2) diagnose cause and forecast future condition in a scientifically defensible fashion to more effectively protect and restore valued ecosystems; and (3) assess current and future ecological conditions, probable causes of impairments, and management alternatives.

Description:

Many States and Regions have begun incorporating landscape and biotic integrity into their Total Maximum Daily Load (TMDL) process. Due to time, money, and man power constraints only around 23 percent of the streams are evaluated during a typical TMDL cycle. Collecting the necessary data and site surveys required to identify sites for a regional or national assessment can be cost prohibitive and merging reference sites from multiple studies can result in data incompatibilities. The objective of this study was to expand the evaluation process using an alternative method for selection of "less impacted" sites for comparison to the other dominant land use in the Mid-Atlantic Coastal Plains Region.

A base network of 174 small (typically first-order) streams was selected across a gradient of hydrogeologic and land-use settings, from a population of 10, 144 first-order watersheds in the region. Of the 174 sites we used a subset of 82 sites having benthic riffle samples for our analysis. We used principle components and cluster analysis to group the first order stream watershed by land use in order to capture the greatest variability across the region. The analyses resulted in clustering the watersheds into three distinct groups. The first group was dominated by natural cover (forest and wetland), the second by urban, and the third by cropping.

We used non-parametric analysis to test differences between cluster benthos and water chemistry data. We found that typical water chemistry measures associated with urban runoff such as specific conductance and pH were significantly higher in the urban group. In the highly cropped group we found variables commonly associated with farming such as nutrients and pesticides significantly greater then in the other two groups. In addition to the higher pollutant loads, the urban and cropped watersheds also had a lower number of intolerant and a higher number of tolerant macroinvertebrate species. Results from this study suggest that landuse based clustering may provide an viable alternative rust step for site selection or for targeting watersheds for monitoring for regional or national scale assessments.

Record Details: