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The
Makauwahi Cave in Hawaii may be the richest fossil site in the entire
Pacific Island region, loaded with bird and fish bones and ancient
Polynesian artifacts. Credit: Alec Burney
By David A. Burney and Lida Pigott Burney, https://www.livescience.com/history/081025-hawaii-cave.html
Natural History Magazine
posted: 25 October 2008 11:09 am ET
From the moment we saw it, we knew the place held many great
secrets. We had been looking for new fossil sites on the south side of
the Hawaiian island of Kauai in 1992 with our colleagues, Helen F.
James and Storrs L. Olson of the Smithsonian Institution in Washington,
D.C., along with their children, Travis and Sydney, and our own, Mara
and Alec.
And what we found was a cave — once a Pleistocene dune field, and
later a sinkhole with pickling-jar powers — that may be the richest
fossi
Sixteen years after our discovery, we have excavated seeds, pollen,
Polynesian artifacts, thousands of bird and fish bones, and more from
this half-acre pile of sediments spanning many millennia. The site has
yielded up some of the island's long-kept secrets, telling of a time when the largest land animals here were flightless waterfowl, such as the turtle-jawed moa nalo (Chelychelynechen quassus).
Moreover, it documents the great changes that occurred when first
Polynesians, and later Europeans, Americans, and Asians, arrived with
boatloads of invasive alien species.
The first boats began arriving roughly a thousand years ago, kicking
off the first of three stages of extinction on Kauai. In the first
stage, Polynesians probably overhunted the large flightless birds,
while introduced rats, chickens, and small pigs disrupted their
remaining nests. Later, but before Captain Cook arrived in 1778, the agriculture of a growing Hawaiian population wiped out more species. Finally, Europeans arrived and brought goats and other livestock that finished the job.
In 2000 we learned the long-lost nineteenth-century name of the
cave, Makauwahi, thanks to a local archaeologist, William K. "Pila"
Kikuchi, who recovered the name from an essay written by a high school
student more than a century ago. It means something like "smoke eye."
That may have been in reference to Keahikuni, a mid-nineteenth-century
native diviner who read the future in spirals of smoke rising from the
sinkhole.
The story struck a resonant chord, as we had begun thinking about
Makauwahi Cave as a preserver of the future at least as much as the
past. In 2004, we were granted a lease on the cave property, including
the surrounding seventeen acres of dunes, wetlands, and abandoned
farmland, by the owners, Grove Farm Company. Using the fossils as a
guide, we set out to suppress plants introduced in the last two
centuries and to favor those that evolved here or were brought from
other Pacific islands by the first human inhabitants.
The most unusual patch of land is on several acres of weedy thicket
formerly used for cane and corn farming. After only three years of
rehabilitation, nearly a hundred species of native and Polynesian
trees, shrubs, and ground covers are now thriving. Planted by
volunteers, including some of the same folks who helped us sift the
fossils from the cave sediments, and the eager assistance of hundreds
of schoolchildren from all over Kauai, the new forest has flourished
beyond all expectations.
Thousands of acres of abandoned farmland throughout the Hawaiian Islands could grow native plants just as well as this!
Unfortunately, many of the animals that disappeared from Kauai were
unique to the island. But even if we can't have giant, flightless
waterfowl,
we can make the area more attractive to the surviving species of birds,
animals, and insects that are indigenous to the island. In this way and
others, we'd like to think we can be a little like old Keahikuni the
Diviner in telling the future. Here at Makauwahi, which has given us
such a powerful sense of the past, we can find a better future for an
island world that was nearly lost.
l site in the Hawaiian Islands, perhaps in the entire Pacific
Island region.
An interesting sight inside a lava tube were roots hanging down from the top.
Credit: Matthew Cimitile
Bones and Birds:
James has made a career of walking and crawling her way through lava tubes and sinkholes, identifying the biodiversity treasures Hawaii once
held. From a large flightless goose to the Hawaiian 'O'o, James and her
colleagues have been putting together Hawaii's natural history with
bird bones as the pieces. Altogether, they have identified around 40
extinct bird species, with more to come.
Uncovering extinct bird bones provides a historical record of Hawaii's natural
environment. These bones tell us what was there before humans arrived
1,000-1,300 years ago and the changes that occurred. Knowing the
composition of the natural Hawaiian environment can inform
conservationists in how they manage and restore ecosystems.
More Going Extinct
This is timely and significant. Many native Hawaiian species, from
plants to birds, are threatened or endangered of becoming extinct. If
habitat modification and threats from invasive species continue, the
stunning array of plants and animals in Hawaii will quickly disappear.
One bird of interest is the Hawaiian Petrel. A seabird that was said
to have darkened the skies of Hawaii has declined considerably and
continued loss of habitat and threats from introduced predators will
further dim this petrel's chances of survival.
James, Ostrom and Fleischer are trying to uncover the size of the
petrel population before human arrival and whether the petrel diet and
feeding locations have changed over time. They are also asking whether
declines in seabird populations affected Hawaiian plant communities by
reducing the flow of nutrients from the ocean to the land.
My time in Hawaii was spent talking to experts, shooting photographs and attempting to film while meandering through lava tubes.
These geologic structures form when the outer part of a lava flow
cools before the inner portion. What's left is a hollow tube of lava
that can extend for hundreds of meters or more. Lava tubes are great
locations to find bird bones. Many birds either fall into these
formations or travel into the tubes, perhaps for protection from storms
or other threats. Since light is minimal and many of the caves have
steep entrances, birds may not find their way out.
Searching for bones
Hours were spent each day navigating the rough terrain of these
caves, going up and down slope, concentrating on where to make our next
step while simultaneously on the search for bones. At certain points
the ceiling extended 12 feet above the jagged a'a (a rough form of lava
rock) while at others it would drop to only three feet. Under low
ceilings we would crouch on hands and knees to maneuver through the
difficult terrain, making sure to keep our balance.
One of the lava tubes was in a native Hawaiian rainforest. Here, the cave was damp and
wet, where water droplets seeped through the upper layer of dried lava
and found their way to the back of your neck. Another tube was located
in an unthinkable desert environment on the islands, where a couple
cold drops of water on the back of the neck was a blessing. After
spending six hours at a time in the cave, you learned to trust orange
tracking tape to find your way out of a tube that could splinter off
into three, four or five different directions.
When bones were found, the team would gather around the site to wait
for James to have a view. After a glance, she would identify a giant
goose or a flightless rail from the small pile of bones and then mark
the site. Upon making our way out of the cave, we would safely store
the bones in "bone boxes" to be shipped to the Smithsonian.
Left with hope
If we weren't on the search for bird bones, we were being educated
by some of Hawaii's top scientists about research and conservation
projects taking place on the islands. Many researchers are trying to
answer basic questions about the nature of petrels, such as where they
breed and how often they leave their nests during rearing of chicks.
Others are finding effective ways to protect the native flora and fauna
found nowhere else in the world.
While spending only a week in Hawaii, I observed the difficult
ecological problems facing the state on many fronts. I left Hawaii not
feeling angry or saddened, but hopeful. Hope from the many dedicated
people who are taking part in discovering the natural history of the islands and preserving the biodiversity that remains. It's a hope that will be
difficult to realize and will require more people becoming educated and
involved in solving environmental problems.
But as one scientist wisely said, by knowing the past and what
naturally occurred, we can manage and preserve the future, not just in
Hawaii but throughout the planet.