World-first method reveals new plant species in endemic Hawaiian genus Schiedea

Schiedea waiahuluensis, a newly discovered species from Hawaii in the carnation family, is likely the first plant to be identified and collected using drone technology.

Researchers used drone photography to spot the unknown species growing on steep, inaccessible cliffs in the Waiahulu region of the island of Kauaʻi, in an area previously unexplored due to its extreme terrain.

This discovery, published in the journal PhytoKeys, was made possible through the National Tropical Botanical Garden’s (NTBG) botanical drone program, which deploys unmanned aircraft to explore remote cliff environments.

In collaboration with Quebec-based Outreach Robotics, NTBG developed “the Mamba,” a remote plant collection device specifically designed for vertical cliff work. This device was suspended from a drone and used to grab, cut, and collect the plant for study.

The new species belongs to a well-studied Hawaiian lineage in the carnation family. Its genus, Schiedea, consists of 36 species spread across the Hawaiian Islands, with 12 species found only on Kauaʻi.

Schiedea waiahuluensis is found only on the dry cliffs of Waiahulu, with an estimated population of around 345 individuals, primarily growing on bare rock surfaces in small pockets of soil. The fragile habitat is under threat from invasive plant species and feral goats, making conservation efforts crucial. Further surveys are planned to assess the full distribution and conservation needs of the species.

Authors Stephen Weller and Ann Sakai from the University of California, Irvine note, “S. waiahuluensis has a combination of traits that would have been very difficult to predict, and upended our notions about diversity in Schiedea, even after decades of research on this genus.”

Lead author Warren Wagner, a research botanist at the Smithsonian Institution, states, “The new development of the NTBG drone program provides a major new tool in biodiversity research that has allowed for better assessment of species distribution and status as shown by drone missions on the inaccessible cliffs of the major canyons on Kauaʻi.

“It has revealed populations of species presumed extinct, such as the recent rediscovery of Hibiscadelphus woodii, a relative of Hibiscus, mapped populations of Schiedea waiahuluensis, and collected seeds via drone for establishment of a conservation collection of this species.”

This discovery, following more than 40 years of research on Schiedea on Kauaʻi, demonstrates the vast potential for future discoveries of native plants across the Hawaiian Islands through drone technology, and highlights the burgeoning role of drones in advancing conservation efforts and preventing plant extinctions.