Invasive species or ecosystem killers

2024 Author: Seth Attwood | [email protected]. Last modified: 2023-12-16 15:55

Vast expanses of dead, scorched earth. Millions of dead and destitute. These are not the consequences of a supervolcano eruption - just rabbits. Everyone knows where the road paved with even good intentions leads: brought to Australia for breeding "like in good old England", they quickly turned into a natural disaster.

Domesticated rabbits arrived in Australia and neighboring islands in early 1788, along with the first European settlers. People took their familiar pets on board to provide themselves with provisions on the way and for the first time of life on the new continent.

According to a census taken at the end of the same year, the colony numbered just over a thousand white Australians, as well as 29 sheep, 74 pigs, 7 horses and cows, and 6 rabbits.

Boxwood moth

Russian Far East, China, Korea, South India => Europe

Caterpillars of this butterfly came to Russia by accident. They were brought from Italy with seedlings of evergreen boxwood for landscaping the Olympic village in Sochi. Soon they destroyed the relict grove of the Colchis boxwood and put the view on the brink of extinction. Also destroys euonymus and holly.

Continental invasion

In just a few decades, the situation has changed dramatically, and the rabbits have displaced people in the position of the most numerous settlers: in other estates they have already walked in the thousands.

In the 1840s, their number crossed the million mark, and in 1859, when Thomas Austin crossed them with more hardy wild brethren and released the resulting offspring for free grazing, a disaster began, the consequences of which the Australians are still raking. The continent's rabbit population marched uphill with strong, hurried leaps.

Rabbits destroyed local ecosystems, destroyed weak vegetation, and depleted soil and resources. There were more of them in Australia in the 1920s than there are people on Earth today.

And this is despite the fact that since the 19th century, the inhabitants of the colony began to fight in an organized way with an unprecedented misfortune: shoot, poison, and separate with fences. In fact, rabbits climb badly, and they tried to stop their spread by special fences buried in the ground from the digs.

Echinocystis spiny

North America => Central and Eastern Europe, the countries of the former USSR, the Far East of Russia

Creates heavy shade, causing local coastal plants to lack light and die.

The first barrier was installed in 1893 and stretched for several kilometers, and soon the individual structures began to be combined with each other. Today, the largest of them - the "Great Queensland Fence" - has a perimeter of 555 km and protects 28 thousand km2 of agricultural land from rabbits. In other areas, the animals themselves were surrounded by a fence.

This is a rather cruel measure: in arid areas in the heat, rabbits died en masse from thirst - but more of them were born anyway.

Rabbit genocide

In 1887, in an attempt to stop the invasion of rabbits from the southern states of New South Wales, he offered £ 25,000 for an effective natural remedy for rabbits. Louis Pasteur himself, at that time already a world famous scientist, responded to the proposal.

His idea was to use a biological weapon - the bacteria Pasteurella multocida, which causes cholera in chickens. For several years, their effectiveness was tested on rabbits and even tried to breed more dangerous strains by selection. The animals in the laboratory did get sick and die, but even Pasteur failed to demonstrate that rabbits could transmit this infection to each other. The reward remained in the treasury, and the rabbits continued to breed.

Ash-leaved maple

Canada => Europe, Russia, Central Asia

It grows faster than most trees and displaces them from floodplain forests. Interferes with the development of young willows and poplars.

In the 1950s, viruses were also involved in the fight against the scourge: wild rabbits were infected with myxomatosis, which was fatal for them, and domestic ones were vaccinated against it. This measure even worked: by 1991 there were only … 300 million wild rabbits in Australia. At the same time, most of the survivors received resistance to myxomatous infection.

Rabbits began to multiply again, and soon people were testing a new tool for rabbit genocide, the calicivirus, which causes hemorrhagic fever in rabbits. Back in 1995, before finishing work, he "escaped" from the laboratory where the infected animals were kept, and began to spread across the continent.

Javan mongoose

South Asia => USA, Central America and the Caribbean, Japan, Croatia

On all the islands where these animals were brought, they were planned to be used to kill mice and rats. However, Javanese mongooses preferred easier prey - eggs from birds, reptiles and amphibians. Many of them have become rare or even close to extinction due to the Javanese mongooses.

In less than a year, the calicivirus has settled in Victoria, New South Wales, Western Australia and the Northern Territory and killed more than 10 million rabbits.

But history repeated itself: by 2010, animals acquired resistance to the virus "from the nineties". However, the breeding of new, more dangerous strains is much better organized today than in the days of Pasteur, and in 2017, animals infected with a new variant of the calicivirus, much more infectious and deadly, were released into the Australian open spaces. The battle continues.

Yeah

Central and South America => North America, Spain, Japan, Taiwan, Thailand

The “station wagon” toad eats almost any small animal. It emits an extremely dangerous poison, therefore it has no natural enemies. Poisoning cases are known for both livestock and humans.

Perfect storm

There is no big mystery in this local evolutionary success of rabbits. On the new isolated continent, they did not meet their usual enemies, but they found a lot of suitable food. There were no parasites that would reduce their numbers in Australia, Tasmania and New Zealand.

Mild winters allowed breeding all year round - and humans gave the rabbits a great start: at first they were bred not only for food, but simply to create cute landscapes that remind colonists of the meadows of their native England. Plus, farmers cut down dense thickets, filling the vacated land with cereals and garden trees.

In such a community, the rabbits didn't just have more food, it was even easier to get.

Caroline squirrel

USA, Canada => UK, Italy,

Ireland, South Africa

Transfers viruses that infect ordinary proteins. Competing with them and displacing them, endangering them. Strips off the bark of European beeches and white maples, which is why these most massive Western European trees die.

It was the “perfect storm”, the coincidence of many factors that worked simultaneously - and destructively. After all, at first no one could have thought that rabbits would be such a misfortune that local plants and birds would begin to die out because of them, and the upper layers of the soil, deprived of protection from leaves and roots, would lose moisture and succumb to monstrous erosion.

Only now are we beginning to understand that species with different ecological roles are needed for balance in any natural community. Where there are herbivores, there must be predators - otherwise they will destroy the vegetation. Many trees won't last long without fungi, and even parasites serve as useful limiters. When there is no natural regulation, big trouble awaits the ecosystem.

Global invasion

Natural limitations restrain the equally natural tendency of any organism to maximize reproduction and dispersal. But man turned out to be a new factor destroying this balance.

He moves faster and faster across the planet, overcoming obstacles in the form of mountain ranges and oceans, deserts and tundra, and - willingly or unwillingly - carries fellow travelers. Not encountering noticeable resistance in a new place, organisms can multiply rapidly, becoming aggressors and destroying local ecosystems.

Raccoon

North America => Russia, Belarus, Georgia, Azerbaijan, Belize, Japan, countries of Western and Central Europe

Destroys native species of amphibians and reptiles. It successfully competes with the badger and drives it out.

The ability to live in a wide range of conditions and eat a wide variety of foods helps to compete successfully with native invasive species. A special advantage is given to toxins, to which local competitors have no time to develop antidotes.

The problem of combating them is also that large-scale attempts to destroy them and “return everything as it was” are fraught with no less danger than the very appearance of alien organisms in a new environment. Poisons? They infect whole groups of animals and plants indiscriminately. Natural predators? In a new place, and they often switch to local, more accessible victims.

Rotan

Russian Far East, North Korea, China => Europe (including Russia), Kazakhstan, Uzbekistan, Lake Baikal

In reservoirs without large predators, it destroys all other species of fish. Causes significant damage to fish farms.

In general, it is impossible to stop the invasion of invasive species, the history of the great confrontation between Australians and rabbits is a vivid confirmation of this. Their victorious march can only be slowed down, but for this each of us must participate in the battle. Many countries publish lists of invasive organisms, with descriptions and photographs.

Those who have found a new potentially dangerous object should inform the scientists about it (in Russia, such a project works, for example, for the hogweed Sosnovsky) - to the "headquarters" of the fight against invasion. Be aware of the risks associated with any spread of alien species.

Call on the authorities to take scientifically sound and serious measures. After all, the most successful and dangerous invasive species is humans, which means we have a chance to take control of the rest.

Sosnovsky's hogweed

Caucasus, Transcaucasia, Turkey => European part of Russia, countries of the former USSR and Eastern Europe

Shades and displaces native plants, multiplying and spreading rapidly. Skin contact with juice causes severe photochemical burns, sometimes even life-threatening. Map of distribution of Sosnovsky hogweed in Russia - borshevik.tilda.ws.