NERL Research Abstract EPA's National Exposure Research Laboratory GPRA Goal 8 SOUND SCIENCE, IMPROVED UNDERSTANDING OF ENVIRONMENTAL RISK, AND GREATER INNOVATION TO ADDRESS ENVIRONMENTAL PROBLEMS FY 2003 Annual Performance Measure (APM) # 7 Significant Research Findings Assessing the Accuracy of Airborne Hyperspectral Data For Mapping Opportunistic Plant Species in Great Lakes Coastal Wetlands Scientific Problem and The aquatic plant communities within coastal wetlands of the Laurentian Great Policy Issues Lakes (LGL) are among the most biologically diverse and productive ecosystems of the world. Coastal wetland ecosystems are also among the most fragmented and disturbed, as a result of impacts from land-use mediated conversions. Many LGL coastal wetlands have undergone a steady decline in biological diversity during the 1900s, most notably within wetland plant communities. Losses in biological diversity within coastal wetland plant communities may coincide with an increase in the presence and dominance of invasive non-native and aggressive native plant species, similar to invasions observed in many other ecosystems. Research also suggests that the establishment and expansion of such opportunistic plant species may be the result of general ecosystem stress. Reduced biological diversity in LGL coastal wetland communities can frequently be related to disturbances such as land-cover (LC) conversion within a wetland or on the edges of wetlands. Disturbance stressors may include fragmentation from road construction, urban development, agriculture, or alterations in wetland hydrology. However, little is known about the specific ecological relationships between landscape disturbance and plant community composition. Remote sensing technologies offer unique capabilities to measure the presence, extent, and composition of plant communities over large geographic regions. However, the accuracy of remote sensor derived products can be difficult to assess, owing to both species complexity and the inaccessibility of many wetland areas. Thus, coastal wetland field data, contemporaneous with remote sensor data collections, is required to improve our ability to map and assess the accuracy of remote sensor derived wetland classifications. The approach of this research was to assess the utility and accuracy of using airborne hyperspectral imagery to improve the capability of determining the location and composition of opportunistic wetland plant communities. Here we specifically focused on the results of detecting and mapping dense patches of the common reed (Phragmites australis). Typically, Phragmites spreads as monospecific "stands" that predominate throughout a wetland, supplanting other plant taxa as the stand expands in area and density. Phragmites is defined as a facultative-wetland plant, which implies that it usually occurs in wetlands, but occasionally occurs in non-wetland environments. Thus, it can grow in a variety of wetland soil types, in a variety of hydrologic conditions (i.e., in both moist and dry substrate conditions). Compared to most heterogeneous Research Approach ------- plant communities, homogeneous Phragmites stands tend to provide low quality habitat or forage for some animals and thus reduce the overall biological diversity of wetlands. From a resource management perspective, Phragmites establishment and expansion is difficult to control because the species is persistent, produces a large amount of biomass, propagates easily, and is very difficult to eliminate with mechanical, chemical, or biological control techniques. The study site was the Pointe Mouillee wetland, one of thirteen coastal wetland field sites currently undergoing long-term assessment by the EPA. Results and The accuracy of airborne hyperspectral data was assessed for detecting dense Implications patches of Phragmites australis in LGL coastal wetlands. This study provided initial research results from a wetland complex located at Pointe Mouillee, Michigan. Assessment results from wetland field sampling indicated that semi- automated mapping of dense stands of Phragmites were 91% accurate using a supervised classification approach. Results at Pointe Mouillee are discussed in the larger context of the long-term goal of determining the ecological relationships between landscape disturbance in the vicinity of wetlands and the presence of Phragmites. Research Lopez, R.D., C.M. Edmonds, D.T. Heggem, A.C. Neale, K.B. Jones, E.T. Collaboration Slonecker, E. Jaworski, D. Garofalo, and D. Williams, (in press). An Ecological and Publications Assessment of Opportunistic Plant Species in Great Lakes Coastal Wetlands Using Airborne Hyperspectral Data in (R.S. Lunetta and J.G. Lyon, eds.) Geospatiai Data Accuracy Assessment. Report EPA/600/R-03/064, U.S. EPA, Las Vegas, NV. Capodivacca, M., D. Jayawickreme, E. Jaworski, and R.D. Lopez. 2003. Digital Image Analysis and GIS Techniques for Vegetation Mapping in Pointe Mouillee State Game Area. The Michigan Academy of Science, Arts, and Letters. Holland, Ml. March 21-22. Jaworski, E., D. Jayawickreme, M. Capodivacca, and R.D. Lopez. 2003. Recent Spread of the Invasive Plant Phragmites australis in Michigan's St. Clair River Delta. The Michigan Academy of Science, Arts, and Letters. Holland, Ml. March 21-22. Lopez, R.D., C.M. Edmonds, A.C. Neale, K.B. Jones, D.T. Heggem, J.G. Lyon, D. Garofalo, E. Jaworski, M. Capodivacca, and E.T. Slonecker. 2003. Landscape-scale monitoring of an opportunist: Phragmites australis in Great Lakes coastal wetlands. International Association of Landscape Ecology Symposium. Banff, Alberta, Canada. April 2-6. Lopez, R.D., and C.M. Edmonds. 2003. Remote Sensing Techniques for Detecting Invasive & Opportunistic Plant Species in Great Lakes Wetlands. U.S. Geological Service Upper Midwest Environmental Sciences Center. La Crosse, Wisconsin. April 8. Lopez, R.D., C.M. Edmonds, A.C. Neale, K.B. Jones, D.T. Heggem, J.G. Lyon, D. Garofalo, E. Jaworski, M. Capodivacca, and E.T. Slonecker. 2003. Remote Detection of Invasive and Opportunistic Plant Species in Great Lakes Coastal Wetlands. EPA Science Forum 2003: Partnering to Protect Human Health and the Environment. Washington, D.C. May 5-7. Lopez, R.D., C.M. Edmonds, and J.G. Lyon. 2003. Hyperspectral remote ------- sensing, GPS, and GIS applications in the monitoring of wetland-opportunistic plant species. International Meeting of the American Society of Agricultural Engineers. Las Vegas, Nevada. July 29-31. Lopez, R.D., C.M. Edmonds, A.C. Neale, E.T. Slonecker, K.B. Jones, D.T. Heggem, J.G. Lyon, E. Jaworski, D. Garofalo, and D. Williams. 2002. Initial Results from and Ecological Assessment of Invasive and Aggressive Plant Species in Coastal Wetlands of the Laurentian Great Lakes: A Combined Field-Based and Remote-Sensing Approach. EMAP Symposium 2002: The Condition of Our Nation's Streams and Rivers from the Mountains to the Coasts. Kansas City, MO. May 7-9. Lopez, R.D., C.M. Edmonds, A.C. Neale, T. Slonecker, K.B. Jones, D.T. Heggem, J.G. Lyon, E. Jaworski, D. Garofalo, D. Williams. 2001. An ecological assessment of opportunistic plant species in Great Lakes coastal wetlands using airborne hyperspectral data. ASPRS/USEPA Remote Sensing and GIS Accuracy Assessment Symposium. Las Vegas, Nevada. December 12-14. Future Research Applications of these techniques and results to other regions within the Great Lakes Basin are the basis of additional research, currently funded by the Great Lakes Commission. Questions and inquiries regarding this research can be directed to: Ricardo D. Lopez, Ph.D. U.S. Environmental Protection Agency, Office of Research and Development, National Exposure Research Laboratory, Environmental Sciences Division, Landscape Ecology Branch 944 E. Harmon, Las Vegas, NV 89119 Phone: 702-798-2394 FAX: 702-798-2692 e-mail: lopez.ricardo@epa.gov ------- |