The wild north side of Kaua’i, Hawaii is one of sheer cliffs, waterfalls and incredible biodiversity. Combine that with one of the wettest locations on Earth and it is nearly inaccessible to humans.
The rugged cliffs of Kalalau Valley, however, are of great interest to botanists at the National Tropical Botanical Garden (NTBG) as they are home to 51 federally endangered plants. The Kalalau Valley flourishes with plant diversity and species unlike anywhere else in Hawaii.
Researchers with NTBG have taken to unmanned exploration of the inaccessible valley through drones. The use of drones allows researchers up-close views of the valley, “NTBG revolutionized cliff survey in Hawaii in the 1970s utilizing ropes, and now we are applying drone technology to go even further,” says Ben Nyberg, GIS coordinator for NTBG.
In January 2019, Ben made an unexpected discovery, several Hibiscadelphus woodii plants growing on the cliff face. Hibiscadelphus woodii was first discovered in 1991 by botanist Ken Wood and named 4 years later after Wood. Just a couple of decades later in 2016, the relative of the hibiscus was believed to be extinct.
I remember the excitement at the National Tropical Botanical Garden when Ken Wood found a then unnamed hibiscus on the remote Nā Pali cliffs of Kaua’i. It was later named for him, Hibiscadelphus woodii, and rightly so, as he had the extremely risky mountaineering job of finding and collecting it. Since then, it seemed to vanish with no trace. Amazingly, it was rediscovered thanks to the tools of modern science. This calls for a celebration in that the last breath of this eons old species was not extinguished, but like Lazarus, came back. Modern conservation efforts like those at NTBG deserve our support so plants like this hibiscus will not suffer the misfortune of the void again. – Greg Nace, former NTBG Assistant Director in charge of collections.
Only four individual Hibiscadelphus woodii were found in 1991, which were later crushed by falling boulders. The flowers are a vibrant yellow and transition to maroon as it ages. Attempts at grafting or cross-pollinating the thought to be extinct H. woodii were unsuccessful.
The drone that re-discovered H. woodii was piloted by Ben Nyberg, a GIS coordinator for NTBG and operator of the drone program for NTBG.
The use of drones has opened up new opportunities to document and discover plants in hard to reach areas. The H. woodii were discovered 600 feet below the top of a cliff face, making it extremely difficult for anyone to ever survey. “The early results are promising, and it’s exciting to think about all the unexplored cliff regions of the world, and how this technology can be deployed,” Nyberg says. “On a personal level this story is inspiring because Ken discovered this species, he gave his all to keep it from going extinct, those plants were was lost and now we’ve worked together to rediscover it.”
Using drones has helped discover plants in hard to reach locations, increased safety and eliminated the possibility of researchers accidentally destroying vital habitats. The next step will be to use a specialized drone to sample these endangered species only found on the north shore of Kaua’i.