The Makauwahi Sinkhole, the largest limestone cave complex in the Hawaiian Islands, is yielding an unprecedented look into Hawai'i's history, with a record of life that dates back 10,000 years.
The findings from a multiyear archaeological dig at the sinkhole have profound implications for proposals to reforest parts of the archipelago with native vegetation, since it shows that coastal forests included a wide range of plants long thought to be limited to upland habitats.
The site also reveals a rich array of bird life, and has changed the current understanding of what pre-human Hawai'i looked like.
Several previously unknown bird species have been identified from fossil bones. The complex coastal forest of the region has been intricately described from seed and pollen remains. Two species of plants — kou and hala — that were once believed to be Polynesian introductions have been proven to predate human arrival. There are signs of ancient snails, extinct land crabs and much more.
The impact from the arrival of the first humans in the Islands also is immediately visible in the cave's sediments. There are the bones of rats, which traveled with voyaging Polynesians, and evidence of the immediate collapse of plant species on which rats fed, such as loulu palms. Later there are fishhooks, pieces of outrigger canoes, charcoal from early imu, and other artifacts such as stone tools and a round basalt mirror. And there are human burials, which are being carefully preserved in place.
"You've got this continuous record, like a slow movie through the 10,000 years," said David Burney, a Fordham University professor and director of conservation at the National Tropical Botanical Garden on Kaua'i. Burney, an ecologist and archaeologist, and his wife, Lida Pigott Burney, also are overseeing the reforestation of the cave and its environment with the plants that the evidence proves once forested the region. A partner from the earliest days of the project was the late Kaua'i archaeologist Bill "Pila" Kikuchi.
Charcoal remnants of an ancient Hawaiian seer’s fire can still be found in Makauwahi Cave on the island of Kaua’i. The work this diviner did, telling the future from curls of smoke, inspired the cave’s name. Makauwahi, you see, means eye smoke. And Makauwahi Cave, it turns out, is still informing the future of life on Kaua’i – at least botanically speaking.
Some 16 years ago, paleoecologists Lida Pigott Burney and David Burney began studying fragments of the past they discovered within the confines of the cave’s 400,000-year-old walls. David Burney is also the director of conservation, and the director of living collections, at the National Tropical Botanical Garden on Kaua’i.
During their excavations, the Burneys found seeds and pollen from a rich array of plants that once lived on southern Kaua’i around Makauwahi Cave. Some of these species still survive on the island, but are vanishing as invasive plants take over their habitats.
In an attempt to restore the many different types of native vegetation that once thrived in the area around Makauwahi Cave, Lida Burney has commenced to re-introduce the plants to their former home. Seventeen acres surrounding the cave have been dedicated to this purpose. They make up the Makauwahi Cave Reserve.