Helicopter drones are being used to detect alien invasive plants colonising riverbanks across Northern Ireland.
It's part of a drive led by Queen's University Belfast to clean up waterways in Ireland and Scotland threatened by invasive species, with the hope of restoring millions of pounds in lost tourism revenue.
Covering 21 river catchment areas in Ireland and Scotland, the initiative, called CIRB, is the largest of its kind in Europe and is aimed at clearing aggressive, non-native weeds such as giant hogweed from riverbanks.
Using the latest technology – including four helicopter drones equipped to take aerial photography – CIRB has eradicated 70% of Japanese knotweed, Himalayan balsam, giant hogweed and rhododendron since 2010.
Invasive species are estimated to cost the Northern Ireland economy £47m each year in damage to infrastructure, fisheries, agriculture and forestry.