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Ecosystem Gathered Together: A jungle full of strange things on the far island of Ascension

Ecosystem Gathered Together: A jungle full of strange things on the far island of Ascension

As the one place on earth who qualifies in the middle of nothing Worth it, it’s going up. The island is the size of Terschelling located in the middle of the Atlantic Ocean. If you look it up on Google Maps, you can zoom out eight times before the coast of Liberia appears at the edge of all that water, less than two thousand kilometers away. The volcanic island is so remote that in the million years since it rose from the sea, it has managed to collect only about 120 species of native animals and plants. About a third of these are “endemic”: species that evolved immediately and that occur only on ascent.

The native flora, about 25 species, consists mainly of ferns. No wonder, then, that when British botanist Joseph Hooker visited the fearsome barren island in 1843, the commander of the garrison stationed there asked him how things could be improved a little biologically. They knew it. On Hooker’s advice, Commander obtained seeds and seedlings of hundreds of plant species imported from botanical gardens in England, Argentina and South Africa. Songbirds, birds, hedgehogs, and owls were shipped from Africa and Europe. Rats, geckos, and cats came with ships and various kinds of insects as stowaways on imported plants. And although the additions of plants and animals were initially limited to the inhabited part, they soon spread by themselves across the entire island.

Eco-friendly grab bag

Those who visit the interior today will find an entire cloud forest. The once-barren slopes are now covered with lush vegetation of guava, banana, ginger, African “peanut butter tree”, Madagascar periwinkle, room pine and Australian eucalyptus, and a bamboo forest grows on the highest peak. Hundreds of insects from all over the world gather for their food. Author Fred Pearce call at new world a Occasional rainforest

Following Hooker’s advice, nature went on to figure it out on its own: Species came and went until plants and animals survived that obviously could get along well and came to an ecological comparison indistinguishable at first glance from the real jungle.

And Ascension is not an isolated case: ecosystems are emerging all over the world, made up largely of species recently introduced by humans.

It’s bad news for global biodiversity, all of those environments amplified by exotic species, because you often encounter the same species all over the world in places like this. Although the number of species in one place does not always have to decrease (indigenous ones are replaced by exotic ones), you will find more and more of the same thing on a larger scale: a decrease in biodiversity.

Gallo pictures

However, ecologists are starting to get seriously interested in such new ecosystems† Only because the amount of plants and animals transported by humans is increasing rapidly and in so many places on earth new ecosystems seem to be becoming the norm. Then you better understand how it works.

Because, and this is another reason ecologists look to, new ecosystems often seem to do surprisingly well. Hawaii’s forests with exotic trees, for example, are on par with natural forests in terms of biodiversity, carbon sequestration, and nutrient management, so mentioned A team of American ecologists in 2012 in Environmental Studies

The traditional idea is that a natural biotope such as coral reefs or a rainforest has been achieved in perfect balance through interspecies adaptation: the niches of all animals, plants, fungi and microorganisms have been precisely matched through millions of years of evolution. That a well-lubricated system has been established. But these modern ecosystems are not exactly like that: they are made up of exotic species that have never had the opportunity to adapt to each other. However, such a system is not creaking collapse. how is that possible?

Quick sort process

Ecologists believe that this is due to the fact that the mixture of species in such a system is not an arbitrary mixture, but the result of a rapid succession of ecological processes. From the moment hundreds of alien creatures arrived and settled in the wild in Ascension, a tumultuous dynamic has begun with some species disappearing rapidly, for example losing competition with native or other exotic species. Other species may have quickly become dominant, but were then caught by predators and lost again. We also know that evolution can sometimes happen fast enough to allow the herbivorous insect to adapt to new food plants within a few decades.

So the idea is that new ecosystems The ones we see now in Ascension or Hawaii or in San Francisco Bay are the result of a quick sorting process. In other words: as long as humans provide enough species that have developed their niche elsewhere on Earth, there are always enough ecological disciplines available to build a functioning ecosystem. American rainforest ecologist Dan Janzen called this name environmental composition

cactus feet Works well in volcanic ascents.
Barry Lewis / Getty Images
Beachgoers in the English Gulf On the island of Ascension, which is home to about 800 people.
Barry Lewis / Getty Images

This ecological structure is now being studied in detail on the Hawaiian island of Oahu by ecologist Jenelle Sperry of the University of Illinois. Sperry and her team used camera traps and analyzed thousands of bird droppings (containing hundreds of thousands of seeds). They discovered that the ecosystem is heavily dominated by non-native species: exotic birds eat seeds from exotic trees but also from remaining indigenous tree species. There are no more native birds that eat seeds from native plants – really new ecosystem So. But Found is that the structure of the system (such as the degree of bird food specialization and the way the food web is divided into independent sub-networks) is similar to that of the original ecosystems that have undergone a long coevolution (Science2019).

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Sperry’s team also discovered that evolution played a role in this: the shape of the birds’ beaks differs markedly from that of their ancestors back home. This is the result of the rapid evolutionary adaptation of a new type of food since its introduction (a few centuries ago at the most).

Lemonade

thanks for the environmental composition So, followed by rapid evolutionary adaptation, alien species can be quickly integrated into an ecosystem, Sperry says. “This makes restoring the original ecosystems more difficult than is sometimes thought,” she adds. Then she said it gently. Others, such as Richard Hobbs of the University of Western Australia and the creator of the term new ecosystemmaintain that such new systems are as valuable as those they replaced. They are working systems that have reached a new equilibrium, and intentionally trying to restore the original flora and fauna is a hopeless task, and does more harm than good, he believes.

This is against the sore leg of a group of ecologists and conservationists who see growing interest and appreciation new ecosystems looks sadly. One of the loudest voices among them is the ecologist Daniel Simberloff. Ironically, Simberlove is best known for his experiments in the 1960s in which he completely rid of mangrove islands with pesticides, and then found that a different but equally diverse group of newcomers had amassed a new ecosystem. So you would expect him to see the importance of purposeless colonization by alien beings.

Inside view from Ascension, Which has an area of ​​about 88 square kilometres.
Photo by Jeff Renner/AFP

But Simberloff and his associates fear that Hobbes and his followers’ publications could become a license for governments and corporations to spoil nature and an excuse for conservationists to shed the towel. at a series Opinion articles write that there is still no evidence of this new ecosystems It has already reached a new equilibrium and it is not certain that the change is irreversible and that the old order can no longer be restored.

Hobbes and his followers have not yet been influenced by criticism. When nature gives you lemons, make lemonadeThey write in response. In other words: In a world of the Anthropocene where climate change and human mobility are increasingly mixing ecosystems, we will have to quarrel with the ecological belts we have.