The editor’s choice is the article by Christianson et al.: “Estimating true density in large, alpine herbivores using Google Earth imagery”
Reliable estimates of population size and density are essential for both research and management, yet very difficult to achieve. This is particularly true for wide-ranging species in remote, hard-to-access areas. In this paper, Christianson et al. describe a simple and cost-effective approach to estimate abundance of large, conspicuous mammals in open habitats using freely available Google Earth satellite imagery. They used an independent double-observer protocol to estimate elk Cervus elaphus density in Yellowstone National Park, USA.
While Yellowstone elk have been the subject of numerous studies, density estimates have been limited to their more accessible, lower-elevation winter range; the remote and vast Alpine summer range however that had never been systematically surveyed. Similar survey protocols could be useful also for other large species, especially when high detectability in the open allows for high precision of density estimates, as was the case for Yellowstone elk.