Hawaii, perhaps the most seemingly beautiful state in the United States, looks to most residents and visitors as an island paradise that has not yet been destroyed. In fact, it is a killing staging ground for biodiversity.
A killing stagnant of biodiversity
When Polynesian navigators first set foot in Hawaii in 400 AD, the archipelago was the closest thing the world has ever seen to the Garden of Eden. In that dense forest and fertile valley, there are no mosquito flies, no ants, no stinging wasps, no venomous snakes or venomous spiders, and few thorny or poisonous plants. Today, the above-mentioned "unfortunate" species, which now fill the island, have been brought in by human commercial activities, some deliberately, some inadvertently.
▲Honey spiny wood finch. (Image source wikipedia)
In Hawaii before humans landed, biological species were both diverse and unique. From the seaside to the mountains, it's filled with at least 125 species, and even as many as 145 species of birds that can't be seen elsewhere. Native eagles soar over dense woods, inhabited by strange long-legged owls and honeywhirling wood finches with shiny feathers. On the ground, a flightless ibis, a flying ibis, is foraging with moa, and moa cannot fly, with a body shape similar to a goose, and its beak looks a bit like a turtle, which is the Hawaiian version of the dodo (the big bird of ancient Mauritius). These Hawaiian-endemic creatures are now almost extinct.
Of Hawaii's native birds, only 35 remain, of which 24 are endangered and 12 are so rare that they may never be able to be revived. Only a few survivors, mostly small honey-spiny wood finches, can also be glimpsed in scattered low-lying habitats. Most of the survivors cling to the rain-rich dense forests and alpine canyons, as far away from human tracks as possible. "To see hawaiian birds," Pym, an ornithologist, noted after a series of fieldwork, "you have to get cold, wet, and tired." ”
Today's Hawaii is still rich in biodiversity, but it is mostly man-made: most plants and animals can easily find their source. Among the exotic plants surrounding the resort and hillside shrublands, there are a variety of larks, striped and spotted pigeons, ducks, mockingbirds, warblers, starlings, plum finches, rice-eating birds, and red-crowned waxbills, none of which are native to Hawaii. Like visitors who admire them, they travel to Hawaii by boat or plane. Therefore, the same type of bird can be seen in other temperate and tropical regions of the world.
▲Plum finch. (Image source wikipedia)
Hawaii's plants are equally beautiful, even too beautiful. However, among the plants that occupy the lowlands, there are few objects that were cut down and reclaimed by the Polynesian colonists when they first arrived.
Of the 1935 flowering plants identified by botanists today, 902 are exotic, and they occupy almost all of Hawaii except for the most primitive habitats. Even in the coastal lowlands and lower slopes, which seem to be the most natural habitats, most of their plants are introduced from the outside world. From the perspective of biogeographic distribution, Hawaii's verdant valleys are actually full of alien creatures. Even the garlands that locals help tourists put on are taken from exotic plants.
▲Hawaiian garland. （wikipedia）
Hawaii once had more than 10,000 species of native plants and animals. Many are even considered the most unique and beautiful species in the world. Their source is hundreds of pioneer species, and they are very fortunate to have landed on the world's most distant islands under natural conditions, and it took millions of years of evolution to become such a rich appearance. However, the number of these species has been greatly reduced. In ancient Hawaii, only a wisp of ghost hovered among the mountains, and our planet was even more pitiful because of its tragic experience.
It all started with the earliest Polynesians, who apparently hunted them to extinction when they discovered that there were some flightless, easy-to-catch birds on the island. When colonists destroyed forests and grasslands for farming, other flora and fauna were also eliminated.
▲ Moa birds can't fly and are endemic to Hawaii. (Image source wikipedia)
In 1778, according to the observations of Captain Cook, the first European to discover Hawaii, a large lowland and inland mountain footage was overgrown with bananas, bread trees, and sugar cane. Over the next 200 years, Americans and colonists from elsewhere occupied the land and the rest of the land, planting sugar cane and pineapple as bulk export crops. Today, less than a quarter of Hawaii's land remains intact, and most of it is confined to the steepest and hardest-to-climb parts of the interior of the mountains. If Hawaii had been more flat, like Barbados or the Pacific Atolls, there would have been no trace of its ancient landscape.
Alien creatures landed in Hawaii
Originally, the destruction of Hawaii's fauna and flora was caused by habitat disintegration, but today, the greatest threat comes from alien species. The prehistoric Hawaiian biota was very small and fragile. When the archipelago was colonized, especially after it became the commercial and transportation center of the Pacific Ocean in the 20th century, the influx of exotic plants, animals, and microorganisms from subtropical and tropical regions of the world began to crowd out and eliminate native species.
▲ Hawaii island plants. (Image source wikipedia)
This biological invasion in Hawaii can be seen as a version of Darwin's evolutionary process that has been abnormally accelerated. Before the arrival of humans, there may be only one species that can successfully move across the Pacific Ocean in the millennium. Some come against the wind. This flight does not necessarily require wings, and many flightless creatures are also rolled up by the updraft and then carried away by the wind, as if plankton in the air, involuntarily. Many spiders deliberately join the plankton population. They stand on a leaf or twig and spit silk at the blowing wind, making the silk thread longer and longer until the silk thread is like a balloon, forcefully pulling the spider. At this time, the spider suddenly relaxed, and it rose against the wind.
If the updraft and wind are chosen, they may drift a long distance before landing on the ground – or they will fall into the water and die. Some spiders will even deliberately arrange their landing by rolling up or biting off the silk thread. Therefore, it is not surprising that native Hawaiian spiders are very rich and diverse.
▲Hawaii Beach. (Image source wikipedia)
Other, less experienced travelers are lifted up by storms and sent to the island, or they come across the ocean like travelers or on rafts or clinging to floating debris formed by plants washed down by the flood.
However, before the advent of humans, the probability of creatures drifting to Hawaii to settle down was frighteningly high. For millions of years, although many species have tried this blind crossing of the Pacific Ocean, not many have successfully landed. Even if they did land, these vanguard troops would still have to face many dangers and obstacles.
First, there must be a ready-made ecological niche waiting there – a place suitable for habitation, with suitable food, with partners to mate and few (or even no) predators. Only species that have survived the test and successfully multiplied in this way are eligible to become candidates for evolutionary adaptation in Hawaii's unique environment.
▲ Red-crowned wax-billed finch. (Image source wikipedia)
Over time, they developed genetic traits not seen in other regions, becoming truly endemic to Hawaii. Some creatures, such as sunflowers, honeycombs, and fruit flies, eventually diverged into several different species, each with its own unique way of life, creating an adaptive radiation that also made Hawaiian naturalism brilliant.
Outsiders do evil
Most of the invaders are harmless, and only a small number multiply, large enough to become agricultural pests or endanger the natural environment. But these few out-of-control species do have the ability to cause great harm. Biologists can't yet predict which aliens might become alien species, which is the official term for harmful aliens by FBI officials.
These harmful species are usually humble in their native areas, because they are surrounded by predators and other predators that have evolved with them over time. Now freed from confinement, they have come to Hawaii, a long-isolated and mild environment, enjoying the fruits of super-successful reproduction while suppressing, exterminating or squeezing out native species that are vulnerable to attacks from alien species.
▲ Wild little domestic pig. (Image source wikipedia)
In addition to human influences, the first to destroy the Hawaiian biota were the African big-headed ants and the wild domestic pigs. African big-headed ants live in a super colony with no limit on the number of workers, up to millions of worker ants, and many queens responsible for fertility. As soon as they came out of the hole, it was as if a long sheet of bedding spread, and if other insects stood in their way, they would either be eaten or expelled.
Worker ants are divided into two categories: those that are small and slender, foraging in one-way columns on the ground, and those with large heads, who are adept at dismembering enemies or prey with their large heads and sharp palates. The African big-headed ants are notorious: they wipe out most of the insects native to the Hawaiian lowlands, including pollinators of native flowers. In addition, they also disrupt the food chain. Eliminating insects is tantamount to reducing the food sources of some insectivorous birds, so they are likely to be responsible for the extinction of these birds as well.
▲ Argentinian ants. (Image source wikipedia)
In other areas that are not inhabited by African big-headed ants, another alien super colony, the Argentine ants, dominate the ground in a similar way, using aggressive and venom-secreting strategies to conquer their opponents. When the African big-headed ant meets the Argentine ant, the two legions will fight for the dominance of the small soil kingdom, and the result is to split the ground in two. Only a few flies, beetles, and other insects have a way of escaping their combined slaughter, but most of these survivors are also immigrants. Hawaiian ants, like hawaiian humans, are outsiders who rule over other outsiders in an increasingly impoverished territory.
The fragility of the Hawaiian fauna in the face of invasive ants fits well with a common evolutionary principle. For tens of millions of years, ants have been almost the preyers of the world's most dominant insects and other small animals. They are also excellent body scavengers, and their earth-turning skills are no less than or even better than earthworms. Before humans came to Hawaii, because it was completely isolated, there was never such a thing as ants.
▲ Hawaiian monk seal. (Image source wikipedia)
Similarly, Hawaii's environment is not ready to accept ground-dwelling mammals. Before the advent of humans, only two species of mammals lived in Hawaii: the native grey bat and the Hawaiian monk seal. However, 42 species of mammals were introduced, each of which threatened Hawaii's flora and fauna to some extent.
Other mammals that have been introduced have gradually increased their harm to the environment. Rats, badgers, and feral house cats hunt birds from Hawaiian forests. Goats and cattle gnaw on remnants of native plants on open ground. Some native plant species, with only a small number of individuals left, grow on extremely difficult cliffs to climb, but even there is no safety, because animals foraging on the cliffs may loosen the soil or rocks, causing falling soil or falling rocks and endangering them.
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This article is from Edward Wilson's naturalist book The Future of Life, published in May 2016 by Synopsys Culture.
Edward Wilson is the current leader in the international biological community, a pioneer in evolutionary biology, an authority on ant research, and a master of science. He is currently the Honorary Curator of the Entomological Hall at the Museum of Comparative Zoology at Harvard University.
With his outstanding scientific achievements, he triggered several revolutions in biology in the 20th century: he proposed the theory of island biogeography and laid the theoretical foundation for modern species conservation; created a new discipline of "sociobiology" that triggered extensive discussion between the entire intellectual class and the general public; and advocated the concept of "biodiversity" as an environmental protection concept that affected the whole world.
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