Ranchers, government agencies and private land managers often need to survey vast, remote rangelands to see how they are being altered by floods, forest fires or other events. Ground-based surveys can be costly and time-consuming.  Satellite imagery is improving, but satellites can’t provide the resolution needed. So, USDA scientists are studying Unmanned Aerial Vehicles, a tool used by the military, to see if they may be the answer to keeping an eye on changing land-use patterns across vast tracts of western rangeland.
In a study partially funded by the Bureau of Land Management, researchers took more than 400 aerial images of 700 acres in the Reynolds Creek Experimental Watershed in southwestern Idaho. They assembled the images into mosaics, determined the percentage of vegetation cover using image-processing techniques and compared the data to information collected with conventional ground-based techniques. A second study looked at photographs of different types of vegetation taken during flights over tracts in Idaho and New Mexico.
In both studies, the researchers found the aerial data sufficiently accurate to be comparable to information gathered in ground-based surveys for shrubs, grasses and other plants that can be distinguished by their top canopy layer. But scientists are not getting their hopes up.  Current federal safety requirements and associated costs limit use of UAVs.
NAFB News Service