| Animal illegal immigration often causes environmental disasters The main enemy of the Hawaiian Islands is not volcanoes or hordes of tourists, but ordinary frogs with the strange name coqui. The state authorities recently decided to spend a substantial amount of money from their budget to combat these amphibians. In the near future alone, Hawaii is ready to spend almost $5 million. Now coquis have simply invaded the main islands of the archipelago and have become almost the main species of local fauna.
These frogs are not native to Hawaii. They appeared here only at the end of the last century. Most likely, they were accidentally brought on a ship along with some agricultural cargo. Under natural conditions, coca plants are found in the Caribbean, for example they are abundant in Florida and Puerto Rico. But, having arrived in Hawaii, the foreign frogs discovered that after escaping from their historical homeland, they found themselves in an earthly paradise: warm all year round, quite humid, large free spaces and - most importantly - no predators. After this, coca populations began to explode on the Big Island and Maui.
The main evil caused by “illegal immigrants” is sound. Coquis are exceptionally loud frogs, and the chorus of several hundred of these amphibians can almost drown out the noise of a jet plane taking off. Naturally, Hawaiians don’t really like living in such a cacophony, and they demand that local authorities somehow reduce the amount of coca in the area.
On top of that, the frog population is seriously worrying ecologists, who believe that visitors to the archipelago who have settled in could displace the birds living here from the islands. The fact is that coquis feed on insects and actively compete with birds in this regard. In March of this year, one of the reserves on the Big Island even had to be closed to visitors for several days: frogs that had penetrated here had populated its territory so densely that they threatened the survival of protected bird species. While authorities carried out chemical treatment of the part of the reserve that was particularly hard hit by the coca invasion, people were asked to stay away from these areas.
But the Hawaiians don’t seem to have any meaningful way to deal with visiting amphibians. Thus, most of the five million dollar fund allocated to solve the frog issue will go to the maintenance of additional inspectors called upon to monitor the proliferation of coca. Only $2 million will be spent on exterminating the immigrants. The authorities' main weapon should be citric acid and lime: these chemicals, biologists hope, will help destroy about 80% of the coca population. However, there is no point in hoping that this will radically solve the problem: the surviving 20% are quite capable of multiplying again to the previous level in the shortest possible time. Then, apparently, the authorities will again have to carry out a chemical attack on the prolific amphibians, which easily won the fight for a place in the sun against all the local fauna taken together.
The king of nature is her enemy
However, despite all the harmfulness of American frogs, the greatest harm to endemic species is, of course, caused by humans themselves. Wherever people settle, they reshape the local nature for their own convenience and benefit. Hunters and farmers have always destroyed dangerous predators first. The expansion of arable land reduces the areas where wild animals can live. Biologists, for example, have been complaining for many years that the plowing of plains in Central and Eastern Europe and southern Siberia has led to a sharp reduction in the number of steppe animals and plants. In Africa and South America, equatorial forests are cut down every year, causing local fauna to suffer. Dozens of similar examples can be given.
In addition, it is humans who are the main reason why wild or domestic animals migrate from continent to continent. Most often, isolated island ecosystems suffer from such relocations, as they have difficulty adapting to the emergence of new species - predators or competitors. One of the most famous cases of the destruction of endemic species by people and other illegal immigrants is the fate of the dodo, flightless birds that lived on the island of Mauritius in the Indian Ocean. Through the joint efforts of people and the cats and dogs they brought, the dodo was completely exterminated in less than a hundred years. Sometimes people did not need the help of our smaller brothers: for example, Australian farmers, fearing for the fate of their sheep, exterminated the Tasmanian marsupial wolf completely on their own.
Such a sad fate befell many species of birds and animals that could not withstand competition with humans and the animals domesticated by them. Moreover, we do not know about all biological tragedies. Sometimes the settlers did not bother to describe the local fauna, and when scientists came to the islands, only the most persistent and competitive of the local species remained alive. No one can now say with certainty how many endemic species were destroyed by cats, dogs, pigs, goats, rats and other immigrants on the islands of Oceania and the Indian Ocean.
However, sometimes, having come to their senses in time, people manage to save some endangered animals. For example, the kakapo (owl parrot) barely managed to survive after meeting a person. This almost flightless bird lived in the forests of New Zealand. At first, its population was reduced by the Maori aborigines, who cleared the forests, then Europeans arrived on the archipelago, who not only continued cutting down, but also brought rats, cats and stoats here. As a result, the flightless kakapo, unable to protect its nests from alien predators, is now almost extinct. Now they are trying to revive its population on several small islands, where the owl parrot has no natural enemies.
Immigrants versus natives
Another sad story of illegal immigration occurred on the Pacific island of Guam, owned by the United States. Somewhere in the middle of the last century, the brown boiga, a tree snake native to Indonesia, New Guinea and Australia, was accidentally introduced there. This alien reptile not only easily took root on the island, but also began to displace the local fauna, which did not know how to fight poisonous snakes. Over the past half century, an uninvited guest, feeding on small animals, has already destroyed two species of geckos and skink lizards and sharply reduced the number of island birds. It got to the point that local residents suffering from its bites began to complain about the boiga infesting Guam (fortunately, the venom of these snakes is not too strong and does not pose a danger to human life). Effective methods of destroying aliens have not yet been found.
The struggle between immigrants and natives occurs not only on exotic islands, but also in the Old World we are familiar with. In the UK, for many years they have not been able to find a solution to the problem of American gray squirrels, brought here at the turn of the 19th and 20th centuries. Local red squirrels have completely lost to their larger gray counterparts in the competition. Now immigrants have practically supplanted the native women in England and Wales, redheads retain their position only in Scotland, but even there the “Americans” are gradually expanding their habitat. The question of how to deal with overseas guests was even considered at meetings of the British Parliament. It was proposed, for example, to catch and sterilize visiting squirrels or simply poison them.
It is worth noting that exterminating adapted immigrants and reviving the population of native species is extremely difficult. Successful examples of this kind are practically unknown. The most radical measures were tried in Australia in the middle of the last century, when the authorities tried to start fighting wild rabbits. These animals, brought to the Green Continent in the 19th century, have taken root well and are now the most numerous species of mammals in Australia. To prevent the rabbits from disturbing the local fauna and farm sheep, biological weapons were used against them: they began to be infected with myxomatosis. This helped for a while: within a few years, most of the immigrant population died out, but the surviving animals acquired immunity to this disease and multiplied again.
A similar war has been waged for many years on all continents against the gray rat, which entered Europe from Asia just a few hundred years ago - in the 15th-16th centuries. This pest, ideally adapted to live next to humans, is practically indestructible. Despite the fact that in large cities special services have been established to combat pasyuks, it is not possible to destroy gray rats either with traps, or with poisons, or with the help of cats. By now, rats have settled almost all over the world and live wherever there are cities or villages. Unfortunately, man, having learned to change the nature around him, has not yet been able to master technologies to return ecosystems to their original state.
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Aliens against Belarusians
The expansion of animal species alien to Belarus, which have adapted to the local nature, causes enormous harm to the country’s economy, Deputy Minister of Natural Resources and Environmental Protection of Belarus Valentin Malishevsky said last week. “Large numbers of needlefish and American striped crayfish have appeared in Belarusian rivers, which aggressively take away the living space of local species and contribute to their reduction and then extinction,” Malishevsky said.
He also complained that the American mink had practically evicted the European mink from the territory of Belarus. “The original species of European mink, which was always present in large numbers in Belarusian forests, has practically disappeared. A small colony remains in the Rossony district of the Vitebsk region,” the deputy minister said. Valentin Malishevsky noted that “about 300 thousand dollars a year are spent on the fight against the bivalve mollusk introduced about ten years ago at the Lukomlskaya State District Power Plant.”
“The southern part of the republic is teeming with alien species of animals that have settled and are gradually displacing native species,” the official emphasized. In particular, according to him, at present almost the entire Pripyat River is filled with Black Sea gobies that are alien to Belarus. In addition, Mr. Malishevsky said, “the economy of Belarus and its natural ecosystem were seriously damaged by the raccoon dog, which was brought to Belarus from the Far East several decades ago.” “They multiply quickly, destroying many rare birds, including wood grouse, which are considered a prehistoric species of animals. Also, raccoon dogs, along with foxes and wolves, are the most active carriers of rabies,” the deputy minister said.
Malishevsky also said that in Belarus “there has not yet been any research into what damage the republic receives from alien animals.” However, according to the deputy minister, in the USA this figure annually reaches about $100 billion, in India - $80 billion, in China - $60 billion. INTERFAX Vladimir DZAGUTO |
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