Ben Nyberg was standing on a knife-edge ridge at Hawaii’s Na Pali Coast. His eyes were scanning the leafy recesses and red-rock ridges nearby. The drone buzzed amongst flocks curiously white-tailed tropicalbirds, but it was still quiet.
Nyberg guided the drone towards the opposite ridge and scanned the iPad with his hands. This served as a guide. He saw Wilkesia Hobdyi.
W. hobdyi, a member of the sunflower family and known as dwarf iliau was once plentiful on Kaua’i. The plant became almost extinct after Europeans brought goats into the island in the late 1800s.
W. hobdyi was isolated from continent landmasses and had not developed defenses against hungry livestock like bitter leaves or sharp teeth.
Intrepid botanists have been searching high up for these plants for decades and taking samples. They rappelled down steep cliffs by rope to find what they were looking for.
This daring approach made it easy to overlook plants. The ropes were limited in their reach, clip-ins were rare on steep cliffs and sightlines were frequently obscured by bushes.
Scientists can reach dangerous places now thanks to new technologies. They are able to search for survivors and find them before they’re too late.
Nyberg is the National Tropical Botanical Garden’s GIS and Drone Program Coordinator. He helped to launch an aerial program that used drones to search for rare species.
W. hobdyi was believed to have less than 600 individual plants along the Na Pali Coast. Kauai’s most endangered plants grow only on the highest cliffs. These cliffs are too steep for goats to reach. Nyberg was able to see more than 100 leaves. The drone flew within five meters (16ft) of the greenery and he took high-resolution photographs to back up his findings in the laboratory.
Nyberg and members of the National Tropical Botanical Garden team (NTBG), working in collaboration with the State of Hawaii’s Division of Forestry and Wildlife discovered three extinct species from Kauai. They also found larger numbers of other endangered species, some with smaller populations than 100.
After years of research, the drone eventually found 5,500 individuals. This is a 900% increase in plant population.
Nyberg stated that such discovery was “just excitement”. Nyberg said that even one plant would have been a huge success. We may still have some time to save the species from extinction.
Today two out of five species are at risk of extinction. This is especially true for islands with high endemism, species that cannot grow elsewhere in the world and that are isolated from possible refuges.
Kauai is home to 250 species of plants that are unique to the island.
Many of Hawaii’s plants are threatened by invasive species such as feral pigs and habitat destruction after heavy rainfalls.
According to the 2020 assessment for IUCN’s Red List of Endangered Species, 10% of Kauai’s plants have gone extinct.
Nina Ronsted (director of conservation science at NTBG), who conducted the assessment, said that “Things really are special here because they’re so far from everything.” Each plant has a unique role in the ecosystem.
Critically endangered species such as na’ena’e (Dubautia Waialealae), which grow in island’s boggy forest are species like na’ena’e. A single species’ loss can cause an ecosystem to become unbalanced.
Ronsted stated, “It’s kind of like a stack of cards.” It will collapse if you remove too many.
Finding rare plants is just half of the battle. Botanists must collect seeds and genetic material to protect endangered species. They can then cultivate them in greenhouse nurseries. It is an insurance policy that protects against the possibility of species extinction.
Outreach Robotics, a Canadian research group led by Nyberg, developed a robotic arm that could be attached to drones to remove hazardous parts of plants.
The Mamba is a multi-use aerial manipulator bidirectionally activated robotic arm. It hangs below drones, and has eight propellers.
It can be separated from the Mamba to move fast and accurately in windy areas and prevents it from colliding with cliff walls.
The Mamba can extend to full extent and reach the plant as far as four meters (12 feet) away.
Scientists can remotely control the Mamba’s flexible metal wrist and powerful clippers. Mamba can be programmed to extract samples even from the most fragile and delicate plants. The collection takes less than 10 minutes.
Mamba has collected 29 seeds or cuttings from endangered species so far. This includes samples of the rare violet wahine noho, which was thought to have disappeared on Kauai but has been rediscovered recently by the drone surveyor.
The NTBG nursery is currently growing cuttings and seeds, while others are stored in the seed bank to aid future conservation efforts.
Nyberg stated that the robot could be “the difference between survival and extinction.”
To make a complete comeback, species must be released back into the wild. Within the next year, scientists hope to have them returning to their natural cliffside habitat.
These drones could even be used to drop the collected seeds and pack them in sticky fertilizer balls, which can stick to high cliffs.
They might not even need to be dropped on such dangerous terrain. Nyberg suggested that it is possible for these plants to have been found on flat land before there were goats.