High resolution aerial photographs have important rangeland
applications, such as monitoring vegetation change, developing grazing
strategies, determining rangeland health, and assessing remediation
treatment effectiveness. Acquisition of high resolution images by Unmanned
Aerial Vehicles (UAVs) has certain advantages over piloted aircraft
missions, including lower cost, improved safety, flexibility in mission
planning, and closer proximity to the target. Different levels of remote
sensing data can be combined to provide more comprehensive information:
15–30 m resolution imaging from space-borne sensors for determining
uniform landscape units; < 1 m satellite or aircraft data to assess the
pattern of ecological states in an area of interest; 5 cm UAV images to
measure gap and patch sizes as well as percent bare soil and vegetation
ground cover; and < 1 cm ground-based boom photography for ground truth
or reference data. Two parallel tracks of investigation are necessary: one
that emphasizes the utilization of the most technically advanced sensors
for research, and a second that emphasizes the minimization of costs and
the maximization of simplicity for monitoring purposes. We envision that
in the future, resource management agencies, rangeland consultants, and
private land managers should be able to use small, lightweight UAVs to
satisfy their needs for acquiring improved data at a reasonable cost, and
for making appropriate management decisions.