Identification of Wright fishhook cactus using drone and remote sensing technology

Obtaining accurate population estimates of plants has been an integral part of the listing, recovery, and delisting of species under the U.S. Endangered Species Act (ESA) of 1973 and for monitoring vegetation in response to livestock grazing management. However, obtaining such estimates for many plant species remains a daunting and labor-intensive task. The use of small unmanned aircraft systems (sUAS or drones) may provide an effective alternative to ground surveys for rare and endangered plants.

The objective of our study was to evaluate the effectiveness of using sUAS (DJI Phantom 4 Pro with a 20 MP camera) to survey for Wright fishhook cactus (Sclerocactus wrightiae L.D.Benson), a small (1-8 cm diameter) endangered plant species endemic to Utah, located in southwest USA desert grazing lands. This species functions in enhancing soil stability, providing nectar for pollinating insect species, and increasing biodiversity in hot arid environments.

We used georectified images overl...