Playing Hide and Go Seek in Kalalau Valley

Hawai’i is easily one of the most isolated places on earth, home to over ten thousand species found nowhere else in the world; each arriving as a castaway through the agency of wind and sea thousands of years before human habitation. Without the threat of predation or competition, Hawaii’s native plants and animals developed remarkable adaptations and specializations. Take Hau Kuahiwi (Hibiscadelphus woodii) for example. Its tube shaped flower (similar to a Yellow Trumpetbush), rich with nectar, evolved to perfectly fit the beak of its pollinator, an unknown species of native honeycreeper similar to the ʻamakihi pictured below.

However, only twenty-five years after Hau Kuahiwi’s discovery by botanist Ken Wood, it was deemed extinct in 2016. Like many native species, it has suffered a combination of habitat loss, disease, and displacement by non-native species, all plaguing Hawaii today. Now called the extinction capital of the world, Hawai’i contains 44 percent of the United States Endangered and Threatened plant species despite comprising less than one percent of the nation’s land mass. 

But conservationists are refusing to lose Hawaii’s spectacularly diverse biotia. The National Tropical Botanical Garden (NTBG) is at the frontier of anti-extinction efforts, actively restoring habitats and saving plants from completely vanishing. While the NTBG’s network encompasses nearly 2,000 acres, Kauai’s Kalalau Valley is a particular area of focus. Although its landscape is considered extreme, it homes a number of unique species. Ken Wood, who now works for the NTBG, has been on the lookout for Hau Kuahiwi ever since he discovered it rappelling down one of Kalalau Valley’s cliff faces in 1991.

Hau Kuahiwi can grow anywhere from the base of cliffs near loose volcanic rock to as far up as 915 meters amongst forests of ʻōhiʻa lehua trees. Spotting this shrub is difficult unless its bright yellow flowers that “wine-darken” with age are in bloom. When a rock slide destroyed the last known colony of Hau Kuahiwi at the end of the 1990’s, Wood desperately begun trying to propagate the plant in the lab, but with no success. After the last sighting in 2006, it seemed that Hau Kuahiwi was lost forever . . .

Is it a Bird? Is it a Plane? No . . . It’s a Drone!

Ben Nyberg is a drone specialist who has used drones to create maps, elevation models, and gather aerial images. He realized that these techniques could be implemented in conservation efforts. While working for The Nature Conservancy, Nyberg reached out to NTGB to see if they would be interested in testing drones out in the field. The tests went resoundingly well. Instead of dangerously dangling out of helicopters or hiking through thick tropical bush, Nyberg simply sends up a drone he carries in his backpack. From a point of safety, drones are able to explore areas that would be impossible to reach on foot.

Having worked in the conservation industry for nearly a decade, Nyberg knew about the history of Hau Kuahiwi and like Wood has kept an eye out. Just before Nyberg set for a survey earlier this year, he consulted with Wood as he usually does. With encyclopedia like knowledge of Hawaii’s plant life, Wood hinted this particular survey area is where one might spot the elusive Hau Kuahiwi. As luck would have it, Nyberg captured an image too good to be true.

“We were working from above and going down about 240 meters off the edge of a cliff. We spent a day in the field there checking out an area of couple hundred acres probably. We didn’t notice it from the live view or while we were in the field, but when I brought the drone back to the lab and was looking through the 300-odd photos that I had collected, I saw that we had one photo where the plant was in right in the lower corner almost off the photo. I’m not an expert on the species, but I said, hmm that looks like it.” – Nyberg 

Although Nyberg’s images were promising, the only way to be sure was to survey the area again. Less than a month later after dodging some bad weather, Wood and Nyberg climbed 200 meters back up the same valley Nyberg surveyed before. Unable to go any further, they sent the drone up another 250 meters; Its camera revealing a landscape never before seen by human eyes. Glued to the screen, Wood and Nyberg’s own eyes expertly scanned the verdant vegetation, looking for signs of the extinct Hau Kuahiwi.

“There wasn’t a lot of hope until the drones came along that we’d ever be able to survey those areas,” says Nyberg. With limitless hiding places in the valley, finding incredibly rare plants here seems like a tortured game of Where’s Waldo. But find Waldo they did. There in one of the most remote locations in the world Nyberg and Wood located three Hau Kuahiwi plants. 

Since implementing drone technology, the NTBG has discovered 11 new plants. “Drones are unlocking a treasure trove of unexplored cliff habitat,” Nyberg remarked. He suggested that this could be the first time drones have aided in a species rediscovery. It definitely won’t be the last either. Drones are already ubiquitous in other areas of scientific research, assisting in everything from tracking sharks to measuring ice growth.

Under Pressure

Despite Hau Kuahiwi’s rediscovery, the central issue of accessibility still remains. Because Nyberg and Wood are unable to interact with the plant easily, conservation efforts will remain difficult. And based on Wood’s unsuccessful past pollination and cross-breeding attempts, getting Hau Kuahiwi back to the lab might not be the key to its survival.

With that said, Nyberg is busily collaborating with other specialists to find a solution. He’d like to add features to drones that allow for seed collection, cuttings, or even pollination. He’s also working with a team of computer scientists who specialize in AI (artificial intelligence). Since Nyberg is not a classically trained botanist, most of his week is largely devoted to sorting through the hundreds of photos he takes on each survey. AI software could automate portions of that process, and help get Nyberg out into the field more. Such efforts will undoubtedly continue to revolutionize the way Nyberg and Wood find and manage endangered species like Hau Kuahiwi.

Unfortunately, Nyberg’s survey’s do not always bring home good news. He has found significant evidence of destructive invasive and introduced species, including pigs, goats, and weeds. It seems that even on the remote cliff faces Hau Kuahiwi clings to nature cannot find relief from humankind. With few pollinators, extraordinary isolation, and encroaching competition from alien grasses, the future of Hau Kuahiwi may depend on some combination of innovation and luck . . .

Nyberg seems to have both.

References

• Dasgupta S. (2019). Hunting for rare plants in inaccessible spots: Q&A with drone pilot Ben Nyberg. Mongabay.com
• Mogg T. (2019). Hawaiian Botanists? Drone Discovers a Plant Thought to Be Lost Forever. DigitalTrends.com
• National Tropical Botanical Garden. (2019). Researchers Rediscover Extinct Plant Native to Hawaii.
• Pope, K. (2019). Extinct flower rediscovered in Hawaii, via drones. National Geographic.
• Schlanger, Z. (2019). Botanists rediscover a rare Hawaiian flower thought to be extinct thanks to a drone. Quartz