1. LANDSAT EVALUATION OF TRUMPETER SWAN (CYGNUS BUCCINATOR) HISTORICAL NESTING SITES IN YELLOWSTONE NATIONAL PARK Laura Cockrell and Dr. Robert B. Frederick - Eastern Kentucky University - Department of Biological Sciences Acknowledgments This research was made possible through funding from the Yellowstone Park Foundation and the Society of Wetland Scientists Student Research Grant for support of field work, and a Graduate Assistantship and Research Assistantship from the Department of Biological Sciences at Eastern Kentucky University. Table 1. Calculated mean values from NDVI analysis of various nesting locations. Introduction Trumpeter Swan Rocky Mountain Population Tri-state Flock nests in the Greater Yellowstone region. Lack of high quality nesting habitat may be limiting growth of swans in the Tri-state Flock. The goal of this study was to use Landsat images to discern differences between historical nesting sites and evaluate current nesting sites within Yellowstone National Park. Satellite imagery allows flexible modeling and frequent coverage (16-18 days). Methods Used historical nesting information and archived Landsat imagery from landsat.org to map historical nesting locations. Images were compiled into false-color composites (Figure 1) using ArcGIS (v.10) to compare nesting areas. ‘Image Classification’ tool was used to train image signature classes to identify pixels with similar signatures based on the reflectance characteristics. ‘Normalized Difference Vegetation Index’ (NDVI) used to create a standardized index of vegetation biomass by calculating the absorption of red light and the reflective characteristics of vegetation to infrared light (Figure 2). Amounts of vegetation are calculated by the equation “NDVI = [ (infrared band – red band) / (infrared band + red band) ]”. Results Historical nesting locations of trumpeter swans were mapped to determine habitat changes. Two methods of analyzing images were used: Reflectance classification of composite images using ‘Image Classification’; Quantitative comparison of vegetation biomass using ‘NDVI’ calculations. ‘Image Classification’ was unsuccessful in determining: Aquatic plant community composition; ‘Open Water’ versus ‘Aquatic Vegetation’ classes; Historical versus current nesting locations; Wetland classification (e.g. palustrine, lacustrine, etc.). The ‘NDVI’ tool was able to delineate areas of vegetation growth or reduction (Figure 2). NDVI values range from -1 to +1 where negative values indicate water or rock and positive values indicate higher vegetation biomass (Table 1). Conclusion Landsat images were unable to produce classifications accurate enough to delineate aquatic vegetation communities, or to delineate between wetland classifications or trained vegetation classes. This is likely due to the heterogeneity of aquatic vegetation compared to relatively large (15 to 30-m) resolution pixels within sampled sites. The ‘NDVI’ tool was successful in determining sites with vegetation loss and gain. This tool is valuable for future management objectives as mapping programs are flexible and are easily updated when new images become available. This technique provides an inexpensive method for remote assessment of habitat conditions in areas which swans are known to use. Archived images can provide a long-term monitoring dataset of how habitat conditions have changed for swans within YNP. YNP photo archives Territory1975 MSS1979 MSS1990 TM1999 ETM+2005 ETM + Alum Creek0.470.340.24 0.52 Beach Springs0.210.140.040.090.58 Beula Lake0.07-0.03-0.060.030.14 Cascade Lake0.390.280.17 0.45 Cygnet Lakes0.410.310.220.260.48 East Tern Lake0.430.370.300.270.53 Grebe Lake0.170.050.020.060.24 Grizzly Lake0.180.08-0.010.050.24 Hidden Lake0.410.370.22 0.45 Lake of the Woods0.29 0.160.150.38 Lilypad Lake0.390.320.240.250.38 Riddle Lake0.360.280.200.180.42 Seven Mile Bridge0.260.290.170.200.38 Slough Creek0.100.200.07-0.070.12 Swan Lake0.340.250.180.160.41 Trumpeter Lake0.110.02-0.04-0.030.16 White Lake0.110.13-0.19-0.090.02 Wolf Lake0.400.300.230.210.50 YNP photo archives; photo by Richard lake