Needle in a haystack - detecting hawkweeds using drones

摘要

Orange hawkweed (Hieracium aurantia-cum L.) and mouse-ear hawkweed (H. pilosella L.) are perennial daisies native to Eurasia and have proven highly invasive in several countries outside their native range. Small incursions are present in New South Wales in Kosciitszko National Park and proximate to the reserve (only orange hawkweed). They pose a significant threat to south eastern Australia and are the subject of a New South Wales (NSW) and Victorian joint eradication program, coordinated in NSW by NPWS and partners.A key challenge in the NSW Hawkweed Eradication Program is delimiting the infestation, particularly across the remote and rugged area where the infestation occurs. To supplement existing ground surveillance, NPWS sought to utilise dronesurveying in the orange hawkweed operation as large and remote areas can be surveyed at low cost. Drones capture colour imagery and a specifically designed algorithm automates the detection process. In the 2017/2018 season, during peak flowering, 608 hawas surveyed by drone over 17 survey days. Eight confirmed infestations were detected, including a new location on Happy Jacks Plain.Drone surveys have been incorporated into the program as an ongoing component, and are proving to be a highly cost-effective surveillance method. It is expected drone survey during flowering times will contribute significantly to delimitation of the orange hawkweed infestation and be pivotal in reaching eradication rapidly.