Hawaii and Ecology
Recently, I went to Hawaii (both the state and the island) for a vacation. The island of Hawaii is the largest of the Hawaiian Islands, and is often called “The Big Island”. I went with two of my kids: my 10-year-old daughter and my 14-year-old son. It was their first time on a plane and their first trip to the tropics. It was a great experience for all of us. Hawaii is a fascinating and beautiful place.
The Hawaiian Islands are young, in geological terms, and Hawaii is the youngest of the islands. It is less than a million years old. The landscape is dominated by two massive shield volcanoes, Mauna Loa and Mauna Kea, both of which have peaks over 13,000 ft high. On the south side of the island there is a smaller volcano, Kilauea, which is still active. Magma rises to the surface in its caldera and lava flows down its slopes into the sea. Hawaii has a variety of land and ocean ecosystems. There are coral reefs, lush forests, dry scrub-lands, high mountains and barren lava fields.
The “native” flora and fauna found their way to the islands by crossing a vast expanse of ocean. When Polynesians discovered the islands around 1200 AD, they brought plants and animals with them. Later, European colonization added a huge number of new species. Hawaii is a great location to study ecology, both because of the variety of ecosystems and because of the recent introduction of new species.
Before going on, I should briefly explain what ecology is. The term is often misused to mean something like “environmentalism” or “concern for nature”. Ecology is the study of systems of living beings: ecosystems. It is a subset of biology. It deals with the way that living beings interact to create systems.
We arrived in the early evening, and stepped out of the plane into warm, muggy, flower-scented air. It was dark, so we couldn’t see the landscape, but we could feel that it was very different. We drove to the condo, got the keys out of the lock-box, and settled into our home for the next seven days.
In the morning, we went out for a little walk, and saw many different plants and animals along the way. We saw yellow birds (saffron finches), a small bird with a red cap (yellow billed cardinal), mynah birds, a Pacific Golden Plover and Zebra doves. Many were unfamiliar to me. I learned their names later, when I bought a pocket guide to Hawaiian birds. We also found bright green geckos in the roadside vegetation (gold dust day geckos). They are native to Madagascar, and have become naturalized in parts of Hawaii. They are the most beautiful lizards I have ever seen. They are bright green with blue eyelids, red spots, and golden “dust” on their backs. I also saw a few anole lizards, in drier places, but the geckos were much more common. It became a morning ritual to look for them.
We had breakfast outdoors at a cafe with a view of the ocean. Then we walked over to a nearby beach. Strange black crabs (a’ama crabs) ran across the lava rock like spiders, sometimes jumping from one rock to another, or jumping into the sea. We have crabs back home, but they don’t jump! In the sea, there were bright yellow fish (yellow tangs) swimming in schools. Sheltered pools were full of small fish. Later, I learned that there are almost no tides in Hawaii, so they don’t really have tide pools. They have pools on the shore that are regularly refreshed by waves. We were exploring little seaside pools when we saw a sea turtle swimming by. It stuck its head and flipper out of the water, as if it was waving at us. Then it nibbled seaweed off the rocks. Walking back to the condo, we saw a cattle egret hunting geckos. It speared one and flew away with its beautiful meal wriggling in its beak.
Because the shore at the condo was rocky and the waves were big, we decided to drive to a nearby sandy beach to go swimming. There my kids had their first experience swimming in the surf. It took them a while to get used to it, and there were a few mishaps. My daughter lost her mask after being hit by a big wave. She left the water and burst into tears. She is a good swimmer but she wasn’t prepared for the force of the waves. We left that beach and drove to another one that was more sheltered. The kids had a lot of fun there, swimming over the coral and looking at fish. They saw many different types of fish and a few turtles. After that, we went to a Target store to buy groceries and a new mask for my daughter.
After the first day, we settled into a pattern: breakfast on the lanai, looking for geckos, swimming in the ocean, having lunch on the lanai, relaxing in the condo for a while, going for a drive in the afternoon, dinner on the lanai, watching the sunset, and bed. I made almost all of our meals, so we didn’t spend too much money on food.
We did swim in the surf again. I taught my kids how to dive through waves and swim out past the break. But mostly we swam in the sheltered bays with coral reefs. My kids loved snorkeling and looking at the fish. They made a list of the species they saw, and it grew longer every day. It was more than 20 by the end of the trip. Yellow and achilles tangs were the most common fish, but there were many others. My personal favorite was the orange-spine unicorn-fish. The rocky shoreline was also a great place to explore. The contrast between black rock, white coral and blue ocean was striking. Almost every little pool had fish in it.
The day we went to Kilauea was the only day that we didn’t go swimming in the morning. It was a long and scenic drive. We traveled through a variety of landscapes: wet lowland forests, gardens filled with fruit trees, macadamia nut plantations, dry forests, scrub-lands and grasslands. We saw a wild pig by the roadside, and many different types of birds.
The slopes of Kilauea were mostly covered by a dry forest of leguminous trees and the red-flowered ohi’a lehua. Near the summit, there was a high-altitude cool rain-forest of trees and giant ferns. We went for a little hike in the rain-forest before going to the caldera. Around the smoking caldera, there was a mixture of scrub, grassland and high-altitude forest. It was raining, and you could smell the sulfuric fumes from the volcano. From a distance, we could see magma spurting in the inner caldera. That was my first time seeing an active volcano. Unfortunately, we didn’t have enough time to go to the place where lava flows into the sea. We went for another little hike in the rain-forest, and then we drove down the mountain in the pouring rain.
On the way back, we visited a black sand beach. The beach itself was not that interesting, but there was a freshwater pond with tadpoles and small fish of some kind. We caught tiny black frogs and let them go. When we were driving back to the highway from the beach, I saw nene geese walking on a golf course. I pulled over and took some pictures. They are beautiful birds and extremely rare. They almost went extinct a few decades ago, but are recovering. At the same place, I saw one of the reasons for their near-extinction: a mongoose. Mongooses were brought to the islands to control the rat population, but they had a much more devastating effect on the local birds. The rain resumed, and we drove back to the condo in one of the heaviest downpours I have ever seen.
On another day, after our morning routine of breakfast, swim and lunch, we went to Mauna Kea. Mauna Loa and Mauna Kea are the two big dormant volcanoes that dominate the landscape. The drive went through grasslands dotted with flowering trees and punctuated by desolate lava fields. We saw wild goats and wild chickens. My son had “The Shire” theme song from The Lord of the Rings movie on his phone, and we played that as we drove through the high elevation dry plateau between Mauna Kea and Mauna Loa. The music seemed to fit the majestic and strangely haunting scenery.
There is a big lava field where the road up Mauna Kea turns off the highway. We pulled over to check it out. I saw two wild sheep looking at us, but when I got out of the car they ran away across the lava. Released from the confines of the car, we ran across the barren lava ourselves, enjoying the experience. But then we discovered something that dampened our mood. My daughter saw the first pile of bones, white against the lava. As we explored further, we discovered more and more bones. They were the remains of sheep. I guessed (correctly) that they had been shot.
After exploring the lava field for a while, we went back to the car and drove up Mauna Kea in a thick fog. After driving as far as we could go, we went for a little hike up a cinder cone. There were scattered bushes and small trees in the legume family (mamane) and tufts of grass, but little else. As we left, we saw wild turkeys running across the road.
Driving down, we stopped at the lava field again, and discovered more sheep skeletons. We found a ram with hair still clinging to the bones, and then in a hollow in the lava we made a more gruesome discovery. There was the skeleton of a ewe, mostly bones but with a few tufts of hair. She had been shot in the face, blowing away her nose and upper jaw but leaving the brain intact. She had probably died slowly, maybe over days. Next to her, in a little cave in the lava, lay the skeleton of a lamb that had died where it was curled up, hiding. The hair was still mostly on the bones, with a little desiccated skin. The skeleton was almost completely undisturbed. There was another lamb not too far away. From the remains, I figured out what had happened. The ewe had her lambs on the lava field. Shortly after, she was shot and left to die. Without their mother, the lambs died of starvation.
We drove down the beautiful mountain in silence. The sun set as we drove back.
When we got back, I did an internet search and learned that the sheep had been shot from the air as part of an eradication campaign. They were being eliminated to protect the native vegetation and wildlife.
I explained to my children the realities of life, including the horror of life. The sheep had been released into the wild, and their population exploded. They were transforming the landscape by eating young bushes and trees. Before grazing animals arrived, the landscape was probably a scrub forest. The grazers had transformed it into a grassland. In the long run, their population would be limited somehow, either by predation or by starvation. Human hunting alone probably wouldn’t do it, because these days humans hunt mostly for fun or ego, not for food, so they only want to take mature rams, not ewes and lambs. Killing rams would have little or no effect on the population. The only way to limit the population is to kill females and young. At some point, the government decided to wipe out the wild sheep by shooting them indiscriminately from the air.
Life has a brutal, even horrific, aspect to it. Life necessitates death, and it necessitates premature death. Nature does not follow any moral principles. The sheep that died on that mountain were not guilty of anything other than trying to survive. They were just living their lives. But in doing so, they inevitably came into conflict with other living beings. That is the nature of life. The lamb that died in that cave after losing its mother did nothing to deserve such a fate. But not every lamb that is born can live. Tragedy is built into the nature of life.
Some people might draw a moral conclusion from the story of the introduced sheep: that humans should not “interfere” in nature by introducing species. Are the sheep an “invasive” species that must be exterminated to restore nature to its proper state?
People often view nature as reflecting some moral order, and the human disruption of ecosystems as both unnatural and morally wrong. They view the introduction of new species as an error that we should correct, to restore the ecosystem to its “proper” state. But when was Hawaii in its proper state? Was it before Captain Cook arrived in 1778? Or was it before the Polynesians (the so-called “native” Hawaiians) got there? Or was it before the birds arrived, or before the flowering plants, or before the ferns? Where do you draw the line, and why? Every species that arrived in Hawaii was “invasive” at some point.
The big island of Hawaii is geologically very young. It is part of a small archipelago of volcanic islands in the middle of the Pacific Ocean, far from any major landmass. It is still volcanically active and growing. During its existence, it has acquired species from various parts of the world. Those species were selected first for the ability to cross a vast expanse of ocean, and then for the ability to survive in their new homeland. In spite of its isolation, Hawaii has been colonized by new species many, many times. Some new species evolved there from the colonizers. Each new species had an impact on the ecosystem, if it was successful.
The first arrivals were probably bacteria, followed almost immediately by mosses and ferns. Their spores blew in on the wind from all over the world. Tiny insects and spiders also came on the wind, drifting in as aerial “plankton”. The earliest land ecosystem on the Hawaiian Islands was composed of microorganisms, spore-bearing plants and tiny arthropods. Flowering plants and birds came later, and they probably wreaked havoc on the earlier inhabitants. The fern-moss-arthropod ecosystem was destroyed and replaced by something new. That is how nature works. Some of the newly arrived species gave rise to other forms that filled open niches in the environment. The Hawaiian honeycreepers, for example, evolved from an ancestral finch species.
For hundreds of thousands of years, the few species that managed to colonize Hawaii created a unique ecosystem. It was a little world unto itself, without man and without mammals except for a single bat species.
Roughly 800 years ago, Hawaii was colonized by Polynesians. They brought a number of new species, including pigs, chickens, rats and several plants. Their arrival caused a major shakeup of the Hawaiian environment. Many species disappeared. The human population grew, eventually reaching a new equilibrium that was relatively stable for some centuries. Like every other species, the human population was also limited by premature death, especially from warfare.
Then, about 250 years ago, Hawaii was discovered by European sailors. They brought more new animals and plants, and another major shakeup of the island’s ecosystems occurred. That process continues to this day.
Europeans gave sheep and goats to the “native” Hawaiians. These farm animals went wild in the interior of the island, and multiplied rapidly. In the process, they transformed the landscape, as other animals and plants had done before them. Grazing-resistant grasses replaced trees and shrubs. Some birds that depended on the trees and shrubs became rare or went extinct. The birds had other problems too, such as rats and feral cats.
Without predators, sheep and goats would have turned the dry areas of Hawaii into a desert, until their population was limited by starvation. But the sheep were hunted by humans and feral dogs. Predation maintained their numbers below starvation levels, but they still had a significant impact on the vegetation. The interior landscape of Hawaii was transformed into a grassland with some shrubs, but not a desert.
Hawaii now has a land ecosystem whose largest members are domesticated animals gone wild: sheep, goats, pigs, chickens, turkeys, dogs and cats. Each has gone back to its ancestral ways. One ecosystem was destroyed, and another was created.
The replacement of one ecosystem with another is a natural process. It is part of evolution. It is not something that only humans do, by “meddling in nature”. Evolution creates and destroy ecosystems. And if we destroy an ecosystem, another one will eventually emerge.
The balance of nature is created by the competition for finite resources. Populations can grow exponentially, so if there are abundant resources for a certain species, the population of that species will grow until competition for resources limits it. In a balanced ecosystem, life is equally hard for all species. No species has a growing or shrinking population.
Ecosystems can be thrown out of balance by physical events, such as volcanic eruptions, forest fires, floods, etc. Ecosystems can also be thrown out of balance by the introduction of new species, or by adaptive mutations that occur in existing species. Then populations change until they reach a new equilibrium. New species often replace existing ones, and new adaptations replace old ones. Evolution is a process of change, not a process of maintenance.
Ultimately, populations are limited by finite resources. Proximately, populations are limited by premature death. By itself, reproduction causes exponential growth. A population is stable when premature death balances reproduction. The balance of nature is maintained by a perpetual massacre of the young. Most organisms die young, without reproducing. That is how nature works.
We humans have been able to (sort of) avoid this implication by using birth control to limit our reproduction. That has problems, which I have discussed elsewhere, but we could replace premature death with birth control, if we were rational about it. Unfortunately, we aren’t rational about it, so we probably won’t, and premature death will make a comeback for our species. Humans are a special case, and birth control is a special case within a special case. For all other species, population growth is limited by premature death.
Nature is not just infanticidal. Nature is also genocidal. Successful new variants displace existing ones. Evolution advances by genocide. Sometimes the genocide is gradual, and sometimes it is sudden. Either way, evolution replaces one type of life with another, over and over again. To be creative, evolution must also be destructive.
The human introduction of new species to Hawaii did not destroy a paradise. It destroyed one ecosystem and created another. There is no way to go back to what existed before. Even if all the “invasive” species could be removed (a practical impossibility), the ecosystem has been perturbed so much that it would not return to its former state. Many species that existed before are now extinct. And why would we want to restore its former state? There was nothing intrinsically good about that state. We might judge one ecosystem as better than another, but such judgments are always based on what we want, not what nature wants. Nature does not want anything.
Personally, I would have loved to see Hawaii before the Polynesians arrived, but I also like it the way it is now, with cities, farms and wild areas populated with a mixture of “native” and “invasive” species.
After our trip to Mauna Kea, we had two days left in Hawaii. On our last full day, we went swimming at Honaunau Bay, our favorite snorkeling spot. When we were poking around in a little pool, we found two tiny moray eels (snowflake morays). In the afternoon we went for a walk around Kona, just looking around and shopping for presents for people back home. When we were walking back to the condo along the seashore, we came across a big white-mouth moray eel stranded on the rocks, alive. I picked it up and dropped it into the sea, and it swam away.
On our final day, we packed up, turned in the keys to the condo, and drove away. Our flight was in the evening, so we still had time to do a few things. We did some final shopping in the town for presents. We had lunch at a Subway. Then we went to a nearby mall, so I could have a quiet coffee at the Starbucks while the kids wandered around.
After that, we still had a couple of hours left before our flight, so we decided to check out a beach near the airport. It was open ocean, with big waves crashing on the rocks. There were little pools carved out of the rock here and there, with fish and coral living in them. We scrambled over the lava rock, exploring, feeling the wildness of it. Then we had to go.
As we were driving to the airport, we saw a wild goat standing on a rock, silhouetted against the sky.