Fossils being dug out of prehistoric mud in a sinkhole at Maha’ulepu may help scientists and ecologists find some inspiration for restoring Hawaiian habitats, hopes paleoecologist David A. Burney. The sinkhole is the oldest dated ecological site in Hawai’i, and
Fossils being dug out of prehistoric mud in a sinkhole at Maha’ulepu may help scientists and ecologists find some inspiration for restoring Hawaiian habitats, hopes paleoecologist David A. Burney.
The sinkhole is the oldest dated ecological site in Hawai’i, and one of more than a dozen places around Kaua’i being studied by Burney.
“Studying the past is our best guide to plan a better future,” he said.
David Burney is an associate professor in the Department of Biological Sciences at Fordham University; an associated scientist of the Louis Calder Conservation and Ecology Center and the Universit d’Antananarivo (Madagascar); and an instructor in the Education Department of the New York Botanical Garden. Burney also holds a Ph.D. in zoology with a minor in botany from Duke University.
Burney said that during the 1970s he worked as a commercial fisherman, farmer and park ranger in North Carolina, when he happened to speak on state parks for a local Rotary Club.
He was chosen for the competitive Rotary Club international graduate studies scholarship and earned a masters degree in conservation biology from the University of Nairobi, Kenya.
For the last 14 years, Burney has worked in Hawai’i. His research has focused on endangered species, causes of extinction and using paleontology to study the environment. Paleontology is the study of prehistoric times using fossils of plants and animals.
In the Makauwahi Sinkhole at Maha’ulepu, Burney studies the distribution, placement and age of fossils, spores and pollen found in layers of sediment. The sinkhole is located on land owned by Grove Farm Company, who has allowed Burney’s to research the site since 1996.
“We didn’t want to do anything that would be detrimental, so we turned it over to the experts,” said Allan Smith, Grove Farm’s chief operating officer.
With a team of volunteers and visiting scientists, Burney digs into the earth to find clues about what Hawai’i’s environment what was like about 10,000 years ago.
Numerous visitor publications describe the path to the Makauwahi Sinkhole: Drive past the Hyatt and CJM Stables to get to the Maha’ulepu shoreline. A trail beside the stream leads to a small, triangle-shaped entrance. Crawling through mud is required.
The archeological and cultural significance of the sinkhole is important and further studies are in order, Smith said.
With more people learning the way to the cave, damage to the area was inevitable. A fence across one cave opening protects human burial sites, and a sign warns people the area is being used for research.
“It’s a self contained area in that cave — the area is under their jurisdiction,” Smith said.
Called a “hidden treasure” by some, the sinkhole is definitely a wonder to all who see it first-hand.
The red rock walls of this prehistoric natural sinkhole reach at least two stories up; and the low-ceiling caves seem like something out of a science fiction movie.
Burney received grants from the National Science Foundation, Kilauea Point Natural History Society, Fordham University, National Geographic Society and the Smithsonian to continue his research.
Since 1996 he’s been able to explore what he calls a “poor man’s time machine,” digging about 30 feet into the earth and 10,000 years back in time, he said. Teams of volunteers and visiting scientists help sift through the prehistoric muck and have found fossilized bird bones, fish bones, plants, seeds, snail shells and charcoal, just to name a few.
Within the sinkhole, Burney has dug 15 holes in the ground to find fossils, including two large excavations about 20 feet wide. The larger of the two is 60 feet long, 20 feet wide and about 30 feet deep.
Last Thursday, Burney and volunteers had found various types of plant seeds, shells of now-extinct snails, kukui nut shells and a four-inch piece of firewood, all at least hundreds of years old.
Laboratory tests determine the accurate age of fossils. Burney says the oldest objects found in the sinkhole are about 10,000 years old.
Layers of rock and soil directly reflect the age of fossils. The deeper down something is found, the older it is. This is known to be true, because at the deepest level, mostly native animal and plant remains are found. At the middle layers, non-native plant fossils are found, representing the arrival of European explorers and settlers. Toward the top layers of sediment, Burney said they found very few native animal bones and more modern items.
Volunteers find fossils and artifacts by “wet-screening”: scooping gobs of mud into nested 1×2′ boxes used like sieves, with fine mesh screens attached on one side, then washing the mud through with water.
Because the excavation is below sea level, water must be continually pumped out through hoses. Burney said that the excavation can fill back up with water in just an hour or so.
One of the goals of Burney’s research and fieldwork is “ecological restoration,” the opinion that native plants can be restored in Hawai’i.
Ecological restoration is a popular and controversial idea among Hawai’i landowners, environmental groups and land users. Burney said they are trying to discover what species of plants and animals used to be there and .
“I try to emphasize the idea that we can make more intelligent choices on restoration by studying the past,” Burney said.
Fossils help determine what plants and animals actually lived on the island of Kaua’i before the Hawaiians arrived, Burney said. It’s feasible to recover some plant species that are still found elsewhere on the island.
Burney said that with help from Grove Farm Co., Kaua’i Community College and the National Tropical Botanical Garden, replanting has become more and more successful. Native plants are gradually introduced into an area with non-natives still in the area. After native plants are established, non-natives are removed, allowing native plants to flourish.
“As long as people leave them alone, (the plants) will thrive,” Smith said.
“One thing we’ve realized is we can’t grow native species until we get control of non-natives. Everyone has different ideas on how to accomplish this,” Burney said.
Plants are not the only things that have a chance to be recovered, according to Burney. Groups of large, evolved birds once lived on Kaua’i.
Most of the bone fossils found in Maha’ulepu come from flightless, turkey-sized ducks and birds. Many date back to before human existence- at least 6,000 years ago, according to a 2001 report written by Burney et al. for the Ecological Society of America.
Most of the birds became extinct around the same time as the first evidence of human interaction, about 1,000 years ago, Burney said. The Hawaiians apparently ate them all.
Of hundreds of bird species and subspecies, only two still exist — the Hawaiian Nene goose and Laysan duck, according to Burney. The Laysan duck was once found on Kaua’i about 6,000-7,000 years ago and still has a population of about 500 on Laysan Island, one of the Northwestern Hawaiian Islands about 700 miles away.
The Hawaiian Nene is an endangered species. After near-extinction, a captive propagation and release program begun in England and Hawai’i, still ongoing on Maui, saved this species from total extinction, according to the Hawai’i Department of Land and Natural Resources, who initiated the recovery program. There are about 500 Nene left in Hawai’i, according to recent DLNR research.
Some ducks had hard nodes on their wings probably used for hitting and fighting. Judging from excrement that was preserved more completely at other sites, Burney said he could tell the ducks ate tree leaves and sticks instead of berries and small leaves like regular ducks.
Ducks occupied a role in the pre-human Hawaiian ecosystem that was similar to the role of large land mammals in the continental United States.
If humans had not come to live on Kaua’i and introduced other land animals like goats, pigs and dogs, the ducks could possibly have attained further evolution and become larger-sized, similar to the extinct Australian dodo bird, Burney said.
Staff Writer Kendyce Manguchei can be reached at kmanguchei@pulitzer.net or 245-3681 (ext. 252).
