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ADDING THE THIRD DIMENSION TO LANDSCAPE ECOLOGY
Citation:
Pitchford, A, J. M. Denver, A C. Neale, S. W. Ator, D W. Ebert, AND R. VanRemortel. ADDING THE THIRD DIMENSION TO LANDSCAPE ECOLOGY. Presented at 2002 US International Association of Landscape Ecology Symposium, Lincoln, NE, April 23-27, 2002.
Impact/Purpose:
Overarching Objectives and Links to Multi-year Planning
This research directly supports long-term goals established in ORD's multi-year research plans related to GPRA Goal 2 (Water Quality) and Long Term Goal WQ-2 Assessment of aquatic systems impairment. Relative to the GRPA Goal 2 Water Quality 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" (Water Quality Long Term Research Goals 2 and 3).
Subtask 1 - Impervious Surface Evaluation
This subtask addresses the development of impervious surfaces estimators for local to regional scale assessments of watersheds and their landscape relationship to stream ecology. The amount of impervious surface area in a watershed is a key indicator of landscape change. As a single variable, it serves to integrate a number of concurrent interactions that directly influence a watershed's hydrology, stream chemical quality, and in-stream habitat. It is our working hypothesis that impervious surface area within a watershed, as an independently mapped predictor variable, can be used to generally track a range of watershed ecological parameters (e.g., NPS pollution, biological integrity, TMDLs) that are of concern to local, state and federal environmental managers. The specific objectives of this research are: 1) to quantitatively evaluate the varying remote sensing methods used in mapping impervious surfaces at multiple scales (local to regional), and 2) to relate the varying levels of impervious surface area in watersheds to the environmental condition of multiple water resource endpoints such as streamflow, temperature, and biota.
Subtask 2 -- Landscape Assessments and Evaluations of Best Management Practices: Watershed Demonstrations
Best Management Practices (BMP) encompass a range of strategies to reduce water pollution related to urban and agricultural activities. EPA, through Section 319(h) of the Clean Water Act [PL 92-500], provides grants to states to implement BMPs in areas with suspected or known water-quality problems. Grants for implementation of BMPs have not been tracked or monitored to document their effectiveness. Although effectiveness can be measured in many different ways, one straightforward but important measure is existence. Implementation of BMPs is a voluntary process and actual implementation is not always executed (Nowak 1992). The primary objective of this project is to assess the feasibility of using high-resolution aerial photography and other remotely sensed data to identify the existence of BMPs that were planned under the 319 program. An additional objective is to evaluate the effectives of BMPs implemented by examining monitoring data from about 5 sites in the OW National NPS monitoring system.
There are several potential benefits to determining the feasibility of using the aerial photography for identifying BMPs: 1) since BMP implementation is voluntary and some may not be implemented due to a variety of social and economic factors (Nowak 1992), remote detection of BMPs can provide data to estimate the ratio of BMPs implemented to BMPs planned; 2) remote detection of BMPs provides validation data that can be input into EPA's Grants Reporting and Tracking System (GRTS), and 3) remote monitoring of BMPs over time could be used to develop data on BMP lifespans, providing important data related to social- and cost-effectiveness.
Subtask 3 -- TMDL Non-point Source Assessment Tool
This subtask involves the development of a software tool to assess the potential risks of water bodies to exceed TMDL threshold values established by States. When completed, the tool will allow the user to evaluate watersheds over entire regions. The too
Description:
Landscape indicator statistical models for water quality in streams are commonly developed using land use/land cover and elevation data. However, surficial soils and geologic conditions have many roles in controlling the occurrence and movement of chemicals into shallow ground water and streams. We have incorporated these factors in the Landscape Indicators for Pesticides Study--Mid-Atlantic Coastal Streams. Our study focused on fresh headwater streams for the Coastal Plain to provide data to develop landscape indicator statistical models, characterize regional conditions, and compare subregions within the study area. We used a hydrogeologic framework that combines surficial geology and physiographic setting to delineate 7 distinct subregions within the Coastal Plain. Surface water stream data were collected during a one-time-only stream survey with each subregion represented by 23 - 25 sites. We developed landscape indicator statistical models using stepwise regression to estimate in- stream concentrations of herbicides, nitrate + nitrite, and chloride. Significant variables selected by the stepwise process varied with the parameter modeled and between subregions. Overall variability explained by these models ranged from 44% to 90%. Soil metrics were important in about half the models, sometimes explaining more than 25% of the variability.