Pele lobeliad flowers with nectar droplet. The abundant nectar serves as a food reward for visiting honeycreepers/Photo courtesy of Rob Robichaux

A team of biologists has accomplished two herculean feats in Hawaiian plant conservation: the successful reintroduction of the endangered Ka‘ū silversword (Argyroxiphium kauense) and Pele lobeliad (Clermontia peleana) on Mauna Loa and Kīlauea volcanoes in Hawai‘i Volcanoes National Park.

In an article recently published in the leading science journal, Biological Conservation, the biologists described their 20-year efforts on Hawai‘i Island to rescue the plants from the edge of extinction.

“It’s been two decades of painstaking efforts by devoted individuals from federal, state and private agencies and institutions to save these plants,” said Hawai‘i Volcanoes National Park botanist Sierra McDaniel. “The team used technical rope systems to produce cuttings from Pele lobeliads in the rainforest canopy, flew by helicopter to remote volcanic slopes to rescue Ka‘ū silverswords, and worked long hours in the field and greenhouses to save them. It’s impossible to describe the joy we feel to see these plants thrive in the wild again.” 

The 11-page article describes the efforts and plants in detail, with color photographs that illustrate the nature of the efforts and convey the exceptional beauty of the plants. The article celebrates the centennial anniversary of Hawai‘i Volcanoes National Park, which was established Aug. 1, 1916, and is a UNESCO World Heritage Site.

The Pele lobeliad nearly went extinct. Only five remnant plants are known in the wild, but now, more than 1,000 Pele lobeliads have been reintroduced in protected areas in the national park. The effort with the Ka‘ū silversword has been similarly successful, with more than 21,000 plants having been reintroduced in the park. Furthermore, the Ka‘ū silversword has now produced offspring of its own – a key factor for long-term recovery.

Park ecologist David Benitez and Rob Robichaux collecting pollen from a Ka‘ū silversword/NPS, Janice Wei

An important aspect of the work has been linking the reintroduction efforts to landscape restoration at large scales in the park and in adjacent state and private lands, thereby providing opportunities for future growth and expansion of the silversword and lobeliad populations.

“The highly collaborative nature of the work has been the key to its success,” said Rob Robichaux, professor of ecology and evolutionary biology at the University of Arizona, and coordinator of the silversword and lobeliad recovery efforts. “Daunting challenges remain. Yet the story of the Ka‘ū silversword and Pele lobeliad offers hope for a brighter future in which the landscapes of Hawai‘i are once again replenished with its many native plant species, which are true marvels of evolution.” 

Yellow-faced bee on Ka‘ū silversword flower head/NPS, Janice Wei