I find limestone interesting.
For one, it’s strong enough to be used in building construction. Strong enough, indeed, to be called a rock.
Another reason I find limestone interesting is its composition. I grew up in the limestone-rich Midwest. Make that, limestone-rich, landlocked Midwest. And, so, I don’t associate limestone with shells and corals. Of course, I realize that’s a relatively short-sighted view of things back in Illinois, Missouri and Kansas, those places where I once put down roots.
I certainly do associate shells and corals with these Hawaiian Islands. However, Hawaii’s nature is volcanic in origin and that means basalt rock. You know, Pele’s handiwork. Today, you can find places around Hawaii where underground tunnels of lava once flowed. Think of a deserted subway system. That rock is generally black, grey and red in color. Not white, like limestone. Another reason I don’t associate Hawaii with limestone.
And yet it’s limestone that makes the coastline of Mahaulepu so unique. Its surface rock was made over millennia as sand mixed with rain and solidified in a natural concrete process known as limestone. And all this happened on top of a bed of hardened lava.
Interesting tidbit #3: Kauai’s sand is primarily made up of broken bits of shells and corals--organic remains that come from the ocean, not crushed bits of volcanic rock.
So, if you think about it, limestone along Mahaulepu does make sense. Once a few people—including paleoecologists David and Lida Burney and geologist Chuck Blay—explained it to me. A few times.
To make things more interesting, I’ll add this to the mix: The rain that helped make the limestone is the same element that carved out the same rock to create Makauwahi Cave. Rain. That is, water flowing from the mountain to the sea. Fresh water. Not salt water. And, so, the much shorter answer to the question is, “No, Makauwahi is not a lava tube like the sea caves along Napali.”
2. Was that palm tree always here?
No. It was planted after Burney and his team started their archaeological work here. It is, however, a native palm that was chosen precisely because of the fossil record discovered inside the cave.
For those who haven’t been to the cave, we’re talking about the loulu
or (Pritchardia aylmer-robinsonii
). It and all the native flora inside the cave were planted here except for one.
Twenty years ago, this place was overrun with vegetation—non-native vegetation. A banyan tree took center stage in the middle of the open-ceiling cave, its roots snaking through the cracks and crevices of the cave’s inside walls. It was joined by other introduced trees—java plum, haole koa and ironwood—in a matted effort that all but blocked out any view of the limestone walls.
A work crew removed it all in a massive effort that took years. Luckily, though, during the eradication, a few guys recognized and left untouched one particular plant—maiapilo, also known as the Hawaiian caper. It is the only native growing inside the cave today that wasn’t planted. And, when I was there on Sunday, it was blooming. I pointed it out to everyone who came in.
3. I’ve walked this coastline for x years, and I never knew this place was here? How could that be?
The ceiling in the largest room of the cave system collapsed some 7,000 years ago, leaving a giant hole in the ground that measures some several hundred feet in diameter. But, as I mentioned above, the open-ceiling cave—Burney’s giant rabbit hole, so to speak—was camouflaged by vegetation. Burney started digging inside the cave—and into its history—back in 1996. At the same time, his wife, Lida, led the charge in clearing out the invasive species and using what was discovered inside the digging pits—seeds, spores, wood—to determine what natives to plant outside the cave. The result is that the place looks completely different, there’s an actual walking path, and it’s much easier to find.
4. Did Hawaiians live in here?
It would be a cool place to live, no doubt about that, especially on tradewind-less days like we had on Sunday, because the air temperature is decidedly cooler in the back of the South Cave—near the entrance to the passage that leads to the home of the endangered Kauai Cave Wolf spider. (Don’t worry. It doesn’t make appearances.) So, I suppose living creatures did live here, but no discoveries indicate that humans lived inside the cave.
5. What about bats?
Hawaii claims only two native mammals. One, the Hawaiian monk seal. And, two, the Hawaiian hoary bat. Because the bat is tree-dwelling, it does not roost or nest inside the cave, although its remains and the remains of a second bat—now extinct—have been found in the cave’s fossil records.
6. What’s up with the tortoises I keep hearing about? I didn’t know there were tortoises in Hawaii.
For a place with 10,000-year-old discoveries, Makauwahi Cave Reserve is a lively place. Seems like every time I maneuver the dirt road to Mahaulepu, I come upon something new. Last month, kalo lo’i (taro ponds) seemingly appeared like a mirage on the grounds outside the cave. Now, we regularly see Hawaiian stilts and, even, Koloa duck foraging in the lo’i.
And the tortoises are reproducing like rabbits. Except that’s not really true, because the tortoises are all male, and what’s really happening is the reserve is turning into a kind of tortoise rescue, a place for tortoises who have outlived their owners in Hawaii. No, tortoises are not native to Hawaii, but a few have been imported as part of the exotic pet trade, and in a strange twist, they are filling an ecological niche left vacant when some large, flightless browsers with heavy beaks like the jaws of a tortoise went extinct in Hawaii.
(The strangest of this group of birds was a pintail-sized duck with tiny eye sockets, a flattened skull and a long, broad snout. It’s thought that it was flightless, nearly blind and foraged on the ground in the dark by feel and smell—much like a blind mole. Its scientific name is Talpanas lippa, but its common name is the Kauai mole duck. It’s one of the handful of species that was unearthed at Makwauwahi Cave Reserve that was previously unknown to science.)
Early research with the tortoise show that they prefer to eat non-native weeds and leave Hawaii’s native plants alone. Bizarre, I know. But maybe the deterrents developed by native plants—prickly leaves, thorns and/or toxins—that prevented the Kauai mole duck and other heavy-billed, grazing birds from eating also work on tortoises. In turn, the tortoises provide us the benefit of invasive plant eradication. Or, at least, a low-cost mowing service.
7. If humans didn’t live here, what was this placed used for?
Now, that’s my favorite question. Another favorite that I rarely get asked is about the rock that just might explain the etymology behind the name of the entire coastline, “Mahaulepu.” But I’m not going to answer those two questions here. You’ll have to come see me some first Sunday morning for those answers.