by Professor Chris Muir (photo above by Rowan Trest)
Hawaiʻi is famous for beaches, surfing, and volcanoes, but botanists know it is also a global hotspot for biodiversity. There are over 1,400 native plant taxa in an area roughly the size of Connecticut and Rhode Island combined, and about 90% of those are found nowhere else in the world. Yet despite comprising less than 1% of U.S. land area, Hawaiʻi is home to nearly 44% of the nation’s endangered and threatened plant species — earning it the grim distinction of being called the extinction capital of the world. Much of the plant diversity arose during adaptive radiations, rapid bursts in species number, during the last 5 million years. Because of Hawaii’s exceptional isolation, very few plants ever made it there prior to human contact, and those that did rapidly evolved into forms drastically different than their continental cousins.
This past January, 11 UW–Madison botany students had the opportunity to experience Hawaii’s remarkable flora firsthand in a two-week immersive field course on Plant Ecophysiology and Adaptive Radiation led by Professor Chris Muir. Across two islands — Kauaʻi and Hawaiʻi Island — the course took students from coastal strand to subalpine summit, illustrating how dramatically plants can evolve when given time and isolation.
Learning botany in the field
Students didn’t read or listen to lectures about plant ecophysiology — they learned it through hands-on experiment in the field. On the coastal Mānā Plain of Kauaʻi, they measured leaf traits in ʻilima (Sida fallax), a Hawaiian plant whose flowers have long been woven into lei by Hawaiian royalty. Students also visited Kokeʻe State Park, guided by the State Botanist Adam Williams, where they measured photosynthesis and water relations in Bidens cosmoides, a striking species thought to have evolved bird pollination by Hawaiian honeycreepers, a novel trait within its genus. The course also included a visit to the National Tropical Botanical Garden, where scientists introduced students to ex situ conservation of rare endemic species, including the loulu palms (Pritchardia spp.).
Many students remarked that a highlight of the trip was our hike through Alakaʻi swamp, technically a bog, perched atop Kauaʻi’s highest plateau, and one of the rainiest places on Earth. On a rare clear day, students hiked through it under blue skies, surrounded by plants found nowhere else on the planet.
From dry lava fields to wet forest
On Hawaiʻi Island, students experienced the island’s dramatic environmental contrasts from the parched dry forests of the Kona side, where they might have expected palm trees but instead found dry forest and grasslands, to the dripping ʻōhiʻa and hāpuʻu tree fern forests of Hawaiʻi Volcanoes National Park. Along the way, they hiked a steep precipitation gradient up Kohala, the oldest volcano on the island, watching the vegetation transform with every few hundred meters of elevation.
Students also contributed directly to conservation. At Puʻu Waʻawaʻa, a dry forest restoration site, they spent a day removing invasive weeds alongside education and outreach coordinators. This service learning deepened their connection to Hawaiian ecosystems in a way that no lecture could.
An unexpected highlight
No amount of planning could have scheduled what turned out to be the most memorable moment of the trip: witnessing Kīlauea erupt, with lava fountaining hundreds of meters into the air above Halemaʻumaʻu Crater. Students watched until sunset. We took many pictures pretending to roast marshmallows over the flames of the lava foundation. For most of us, this will be a once-in-a-lifetime experience.
On the last day, students drove above the clouds to the Mauna Kea Visitor Information Station to see the Mauna Kea silversword (ʻāhinahina; Argyroxiphium sandwicense), one of the most celebrated examples of Hawaiian adaptive radiation, before a sunset aloha dinner on the coast.
As one student put it: “This trip exposed me to a lot of information and topics that I had not explored before. Having the chance to learn by doing, immersed in Hawaiian flora, made this experience very valuable and left me with lifelong knowledge and lessons.”