Laserfiche WebLink
METHODOLOGY <br /> Prairie Dog Town Surveys <br /> Prairie dog towns in the Nucla East Mine study area were initially located and <br /> mapped on a 1" - 400' scale aerial photograph of the area. Prairie dog town locations <br /> were then visited on the ground to ground-truth the accuracy of the preliminary <br /> mapped boundaries and to determine burrow densities for the most significant towns. <br /> Burrow densities were determined utilizing belt transects. Where feasible, belt <br /> transacts were placed along the longest axis of a town. For towns where topography, <br /> fences, and other obstacles prohibited long transects, shorter transacts were placed <br /> across representative portions of the town. In many of the larger towns, additional <br /> transacts were placed in representative portions of the town to provide a better overall <br /> estimate of burrow density. Burrow densities were not determined for towns that were <br /> small, relatively inaccessible, or appeared (by initial ocular estimate) to support low <br /> burrow densities. <br /> Belt transacts were 14 feet wide (7 feet on each of the observer) and were traversed <br /> on foot or on a four-wheeled all terrain cycle (driven slowly, 2 to 5 mph) depending on <br /> the size of the town, access, and vegetation present. Transect locations are shown on <br /> the attached map. Length and the observed number of active and inactive burrows <br /> were recorded for each transect. After transects were completed, the total acreage <br /> sampled and the average number of inactive and active burrows per acre were <br /> calculated for each town. Total acreage occupied by each prairie dog town was <br /> computed from the mapped town locations using digitizing equipment. <br /> Inactive and active burrows were determined by inspection of each burrow <br /> occurring within the belt transect. The presence of spider webs, vegetation, wind <br /> 2 <br />