How do American deer threaten Russia?

Table of contents:

How do American deer threaten Russia?
How do American deer threaten Russia?
Anonim

The idea of ​​moving animals from one continent to another for the sake of "enriching the fauna" seemed to be a thing of the past: people remember too well what problems, for example, the appearance of rabbits in Australia led to. Nevertheless, in recent years in Russia, more and more proposals have been made to acclimatize white-tailed deer from America - and they are supported by the Ministry of Natural Resources. N + 1 understands why zoologists are not happy with this venture, how horned invaders can harm motorists and what has to do with zombie deer.

Successful deer

The cartoon "Bambi" is based on the novel of the same name by the Austrian writer Felix Salten. While working on the film adaptation, employees of the Disney studio made quite a few changes to the original plot, making it simpler and not so dark. In addition, they moved the action from Europe to the United States - perhaps to make it easier for the American viewer to feel the story of Bambi and his friends. So in the cartoon appeared, for example, the skunk Flower - an animal well known to the inhabitants of America. And Bambi himself, who in Salten's novel was a European roe deer (Capreolus capreolus), became a white-tailed deer (Odocoileus virginianus), a typical representative of the American fauna.

Adult male white-tailed deer (Odocoileus virginianus)

The female white-tailed deer (Odocoileus virginianus) and her calf are the real Bambi. Light spots on the hide make it less visible to predators.

Today Bambi remains the most famous deer in the world. Only the reindeer from the team of Santa Claus can compete with him in popularity. But white-tailed deer have achieved success not only on screen, but in real life as well. The range of this species is one of the most extensive in the entire family of deer (Cervidae): it stretches from Canada through most of the United States, Mexico and Central America to Bolivia and Peru. This territory is inhabited by from twenty to forty subspecies of white-tailed deer, which have adapted to various environmental conditions.

Natural range of various subspecies of white-tailed deer in North America

Natural range of various subspecies of white-tailed deer in Central and South America

Most often, these ungulates inhabit plain and, to a lesser extent, mountain forests, as well as woodlands and prairies. In Central and South America, white-tailed deer live in dry tropical and subtropical forests, forests along rivers, and in savannas and mountain meadows. There is even a dwarf insular subspecies O. v. clavium, which live in isolation in the Florida Keys, south of Florida. In other words, white-tailed deer are much more flexible in their habitat selection than most other deer.

In addition to its wide range and ecological flexibility, the white-tailed deer, according to zoologists, is the most abundant species of deer in the world. In the United States alone, where most of the population is concentrated, in 2017 there were 29.5 million of Bambi's relatives. In addition, these ungulates are common in Canada (although more southern populations, especially South American ones, are rare, mainly due to poachers).

There are several reasons why there are so many white-tailed deer. First, the unpretentiousness of these animals allows them to inhabit various biotopes, including those created by man. For example, in northeastern Canada and the Great Lakes region, white-tailed deer have advanced strongly northward thanks to the clearing of coniferous forests and the creation of farmland. Secondly, in many parts of North America, primarily in the east, humans have exterminated large predators, wolves (Canis lupus) and cougars (Puma concolor), which positively affected deer populations.

Finally, the protection of the white-tailed deer played a role. By the end of the 19th century, the number of this species in the United States decreased by the efforts of hunters to about 300 thousand individuals - however, the measures taken in time allowed most of the country's populations to recover. And today, experts believe, even more white-tailed deer live in North America than in the pre-Columbian era.In recent years, however, their number has been gradually decreasing, but so far insignificantly. By comparison, another North American deer, the black-tailed deer (O. hemionus), which is the closest relative of the white-tailed deer and lives in the west of the continent, failed to fully recoup the human losses; moreover, it has become increasingly rare for several decades.

Perfect game

The white-tailed deer is one of the most popular trophies for hunters in North America. Every year they hunt several million deer, and without noticeable harm to the population. In the 19th and 20th centuries, they brought the white-tailed deer to the regions where it had never been found. So these animals appeared in the Greater Antilles, in New Zealand and some European countries.

Best of all, the species took root in Finland, where five individuals were brought from Minnesota in 1934. At first, four females and a male of animals were kept in an open-air cage, a few years later they were released into the wild, and in the 48th year several more deer were brought. Soon, their number has already gone to hundreds, and by 2019 the population size exceeded one hundred thousand individuals. In recent decades, these ungulates have gradually penetrated into the Leningrad region - several dozen individuals have settled in areas bordering Finland.

Enthusiasts call for widespread distribution of the white-tailed deer throughout Russia. The fact is that native species of deer, such as roe deer (Capreolus sp.) And elk (Alces alces), are few in most regions of our country, primarily due to poaching. At the same time, white-tailed deer are unpretentious and reproduce quickly, therefore it is assumed that they could take root in vast territories from the southern taiga to the steppe zone and reach a high number. In this case, Russian hunters would have received a new mass species of game. Similar arguments were followed during the resettlement of white-tailed deer in Finland: in the 1930s, the number of ungulates in this country was also small.

For the first time, the idea of ​​relocating American reindeer to Russian lands was announced at the end of the Soviet era. In the USSR, the acclimatization of "useful" plants and animals was generally very popular, especially in the 1920s and 1930s. By the time it came to white-tailed deer, however, biologists and officials were wary of the issue. As a result, plans to import horned Americans did not get progress.

In modern Russia, the white-tailed deer has the status of an agricultural species, which means that it is forbidden to release these animals into the wild, even on the territory of hunting farms (only in the Leningrad region this species belongs to hunting). At the same time, no one forbids bringing them from abroad and keeping them in fenced-in areas for open-air hunting. Now semi-free herds of white-tailed deer live in open-air cages in the Smolensk, Voronezh, Nizhny Novgorod and Tver regions. However, in recent years, proposals for the full acclimatization of this species in our country have been regularly voiced again. And now they receive support from the Ministry of Natural Resources.

At the end of March 2021, the Ministry of Natural Resources presented a bill that transfers white-tailed deer to the status of a hunting species. If it is adopted, then these ungulates can be freely resettled throughout the country - according to the ministry, the best suited for this are the subjects of the North-West, Central, Southern, Volga, North Caucasus and Ural federal districts, as well as the territories of individual subjects of the Far Eastern and Siberian Federal Districts. Officials suggest that this will help hunting farms cope with the consequences of the fall in the number of another popular game - wild boar (Sus scrofa), which was seriously affected by the spread of African swine fever (a dangerous viral disease that entered Russia in 2007) and control measures with her.Of course, in an ecological sense, deer are not analogous to wild boars - however, hunters may well be satisfied with replacing one game with another.

Horned menace

Zoologists, as well as some game experts and even State Duma deputies sharply criticized the plans of the Ministry of Natural Resources. This is not surprising, because previous attempts to enrich the flora and fauna of Eurasia with American species, which were undertaken in the first decades of the existence of the USSR, did not end well.

In some cases, the invaders simply did not take root. For example, striped skunks (Mephitis mephitis) were released in various parts of the country in the 1930s, but they were quickly eaten by predators. Perhaps the fact that some of the animals were sent to the forest unarmed - with the odor glands removed, played a role.

Other projects for the acclimatization of species from the New World on the territory of the former USSR have been successful, but the invaders have turned into pests, causing serious damage to the local nature and economy. The flora and fauna of Eurasia for millions of years developed in relative isolation from the American and were not ready for the appearance of invaders from overseas. Suffice it to recall the American mink (Neovison vison), which almost completely replaced the aboriginal European (Mustela lutreola); striped raccoons (Procyon lotor), massively destroying bird nests in the Caucasus; or muskrat (Ondatra zibethicus) - destroyers of freshwater ecosystems.

Similar situations arise during the reverse exchange, when European and Asian species, for example, starlings (Sturnus vulgaris) or some earthworms, end up in North America. Perhaps the only experiment of this kind that did not lead to sad consequences was the acclimatization of musk oxen (Ovibos moschatus) in the far north of Russia, whose natural range is located in Greenland and Canada. However, in the Pleistocene, musk oxen lived in Eurasia and, most likely, were exterminated by ancient hunters, so they were not brought in, but rather returned after a short absence by evolutionary standards.

Officials from the Ministry of Natural Resources and Environment assure that the appearance of white-tailed deer in Russia not only will not cause any harm to local species of deer (in particular, they emphasize that hybridization between invaders and aborigines is excluded due to the too large genetic distance between them), but will also go to them. benefit. Allegedly, if numerous herds of North American deer appear throughout the country, then roe deer, elk and other local species will less often become victims of hunters. Scientists, however, are not convinced by these arguments.

According to zoologists, if Bambi's relatives appear in Russian forests and reach a high number, the first to suffer - not win - are roe deer, European and Siberian (C. pygargus).

European roe deer (Capreolus capreolus)

White-tailed deer and roe deer have similar sizes (roe deer are slightly smaller) and similar food preferences - all this makes these animals direct competitors. Given that the North American species is more plastic and better adapts to the neighborhood with people, it can easily displace roe deer from many parts of their range. The example of the American and European minks demonstrates that such a development of events is quite real. So Disney's Bambi (white-tailed deer) can replace the original (roe deer) not only in the cartoon, but also in the Russian forests.

Other potential problems associated with the appearance of white-tailed deer in Russia can be predicted by looking closely at the situation in the United States, where these ungulates are very numerous. As we have already mentioned, there are few predators, so there is no one to regulate the number of deer and scare them, preventing them from feeding in the same place for too long and eating too much vegetation. As a result, numerous and fearless deer destroy tree undergrowth, hindering the restoration of forests and depriving the habitat of many animals, for example, grouse birds.They also often eat crops in the fields, causing damage to agriculture, and probably contribute to an increase in the number of ticks - carriers of tick-borne borreliosis, which is dangerous for humans. Considering that in European Russia, as well as in most of North America, there are few predators left that are dangerous for large ungulates, similar troubles may await us.

In addition, an invasion of deer can make life difficult for motorists. In North America, these herbivores often graze near trails, including at night, and often come out onto the road right in front of a moving car. In the United States alone, about a million accidents involving deer occur annually: not only animals, but also people die, and the economic damage from accidents is about ten billion dollars a year. Moreover, deer most often go out on the roads where there are many of these animals, but they have few enemies. If the same conditions develop in some Russian regions, the number of accidents here will increase significantly. In Finland, imported white-tailed deer are already creating problems for both forest plantations and road safety.

Deadly exhaustion

White-tailed deer are not the first ungulates with which they tried to enrich the fauna of European Russia. So, in Soviet times, sika deer (Cervus nippon) were actively imported here, whose natural range is located in East Asia, including the Russian Far East. Some of their acclimatized populations have survived to this day - for example, in the Losiny Ostrov National Park. However, none of them multiplied to such an extent that this led to any serious problems. For comparison, in Japan, after the extermination of wolves in the first half of the last century, there are so many sika deer that they cause serious harm to the environment. It seems that poaching is too developed in our country for at least one species of ungulates to breed to an excessive extent.

However, even if the white-tailed deer brought to Russia do not reproduce as strongly as in the USA and Canada, this does not mean that they do not threaten our nature. Together with wild and domestic animals and plants that people transport from one continent to another, dangerous "free riders" travel the planet: pathogens, parasites and pests that can destroy whole species in a new place of residence. A simple listing of such cases will take several pages. So, the already mentioned African swine fever, exported from Africa with infected domestic pigs, led to a drop in the number of wild boars in Russia and may become fatal for several more rare species of pigs from South and Southeast Asia.

A number of infections circulate in the populations of North American white-tailed deer that the ungulates of Eurasia have never encountered and are not immune to. This means that every relative of Bambi brought to Russia from overseas and released into the wild can transmit a fatal disease to local deer. In the worst case, the number of our deer can plummet, up to the extinction of certain populations and species.

Among the diseases that affect white-tailed deer, the greatest concern among specialists is chronic wasting disease (CWD) - in North America it also affects black-tailed deer, wapiti (Cervus canadensis) and moose. It has a prion nature - it is caused by a protein with an abnormal three-dimensional structure, which stimulates the transformation of proteins homologous to it into their own kind. When a prion enters the body (or appears spontaneously in it), it triggers a chain reaction in the body that leads to the appearance of many improperly folded molecules. Like other diseases of prion origin, such as bovine spongiform encephalopathy (mad cow disease) or kuru (a disease of ritual cannibalistic indigenous people of New Guinea), CWD affects the brain and other nerve tissues and gradually destroys them. Sick deer (most often adult males) become lethargic, tremble, walk with difficulty, drink a lot and produce a lot of saliva. In addition, animals lose weight. Sick animals look so bad that they are sometimes compared to zombies.

Deer with Chronic Wasting Disease Symptoms

CWD, like other prion diseases, inevitably kills its host. However, before this, the prions penetrate the lymphatic system, so that during the illness the animal manages to release into the environment many prion particles that are resistant to ultraviolet radiation, high temperatures and most disinfectants through saliva, urine and feces. Dangerous proteins can wait a long time before they enter the body of a new victim.

Whether representatives of other animal groups are capable of contracting deer prions in the wild is not yet clear. In experiments, scientists managed to infect squirrel monkeys (Saimiri sp.), Genetically modified mice and some other animals with CWD, but still no one knows whether this disease is dangerous for people, for example, hunters who ate the meat of a sick deer.

Chronic wasting disease was first discovered in 1967 in a colorado black-tailed deer living in an open-air cage, and its prion nature was established 11 years later. Since then, CWD has spread widely across North America: its outbreaks were noted in 26 US states and three provinces of Canada - aviary and wild deer of various species and elk were affected. In the most affected regions of the states of Colorado, Wyoming and Wisconsin, more than forty percent of wild adult male deer have become infected. And on reindeer farms, where ungulates are bred for enclosure hunting, sale or for meat, the percentage of infected individuals can reach 90 percent. Of course, all infected individuals go to slaughter, and their carcasses are destroyed.

Prevalence of Chronic Wasting Disease in the United States and Canada as of June 2021

The origin of the disease remains a mystery. Some authors believe it stems from scrapie, a prion disease that affects domestic sheep and goats. It could jump onto deer when they grazed in the same places as livestock.

However, it is highly likely that outbreaks of CWD occurred in North American deer and elk populations long before infection was discovered. From time to time, an incorrectly folded protein appeared in the nervous system of one individual, spread among its relatives, and then the outbreak died out by itself, without leaving the local level. Only human activity allowed the disease to take over most of North America. By transporting deer and their meat from one end of the continent to the other, humans helped the disease travel thousands of kilometers from the site of the original outbreak and conquer new territories (there may have been more than one such outbreak). And high-density aviary populations have become ideal places for prions to spread.

There is no cure or vaccine for chronic wasting disease. This means that there are not many opportunities to slow down the spread of infection - at best, it is careful tracking of all cases of the disease, periodic monitoring of wild populations and the destruction of infected livestock on farms and in aviaries. However, North American deer and moose are unlikely to be doomed to extinction due to CWD. The researchers found that among them there are individuals who, due to certain mutations in the PRNP gene (it is he who encodes a protein that turns into a pathogenic form upon contact with a prion), become infected with a chronic wasting disease several times less often than their relatives (although some of these mutations prolong life to infected animals, which makes them more likely to spread prions). In some regions, where CWD has been present for a long time, the number of deer is declining, but there is a chance that this decline will be gradually compensated by individuals who have migrated from other places, including more resistant to the disease. At the same time, in most regions of the United States and Canada, covered with chronic wasting disease, it appeared relatively recently and did not have time to spread widely in local populations.

The vast majority of deer and elk in Eurasia lack even the slightest defense against chronic wasting disease - which means they can do even more damage than North American ones. Of course, she is not able to jump from North American populations to Eurasian ones in a natural way - but people can help her.

The disease has crossed the ocean at least several times. In the early 2000s, veterinarians diagnosed CWD in a wapiti brought from Canada to a farm in South Korea. To stop the spread of infection, it was necessary to destroy all the livestock on the farm - about four thousand individuals. She then failed to penetrate into wild populations. In 2004-2010, several more cases of CWD reindeer infection were recorded on South Korean farms - each time they were associated with individuals brought from North America. All of them were suppressed and did not break out into nature.

European authorities, alarmed by the situation in North America, began to monitor the health of local deer to identify any cases of CWD import and stop the spread of the infection in time. In 2016, this search yielded the first results: a chronic wasting disease was identified in a wild reindeer (Rangifer tarandus) in southern Norway (this is the first registration of the disease in this species). Subsequently, the infection was recorded in local reindeer several more times. In an attempt to cope with the spread of the disease, it was decided to destroy the entire herd - more than two thousand individuals. And in 2016-2020, experts diagnosed CWD in several elk and one red deer in Norway, Finland and Sweden (but not in white-tailed deer imported to Finland).

The analysis showed that Scandinavian deer and elk suffered from different types of CWD. Reindeer from Norway have suffered from an infectious form that resembles the classic North American and is transmitted from individual to individual. Most likely, it did not penetrate here from the USA or Canada, but arose spontaneously in the local population: this is indicated by the results of additional studies, according to which the prions found in Norwegian reindeer differ markedly from the North American ones. And in moose and red deer, prions did not go beyond the central nervous system and therefore could not be transmitted to other individuals. All of these animals were more than fifteen years old, so the appearance of prions in their bodies could be associated with old age (the longer the body lives, the more likely it is that some of its proteins will fold incorrectly). For the entire population, such cases do not pose a threat and do not require the mass destruction of elk and deer.

The spread of chronic wasting disease in Scandinavia. Cases of a transmissible strain in reindeer were diagnosed in red, and cases of a non-infectious strain in elk and red deer were identified in green. The numbers indicate the year of discovery

So far, Europe remains free of chronic wasting disease epizootics: the Norwegian reindeer outbreak has been localized and suppressed, and other cases identified in Scandinavia are of a type that is not transmitted from individual to individual. Nevertheless, specialists continue to search for cases of the disease among European populations of deer and elk, testing thousands of animals every year and tracking any suspicious cases.

Supporters of the idea of ​​acclimatizing white-tailed deer in Russia argue that the risk of the spread of CWD in our country can be avoided if used to resettle animals from Finland. Since this population comes from deer, which were brought to Europe long before the onset of the current epizootic, they could not get infected from their North American relatives. However, prion infection may well arise spontaneously in the deer population, and it is not a fact that infected animals will be detected quickly enough.While the disease is concentrated at the local level, its spread can still be stopped, but if infected individuals not identified in time are resettled throughout Russia, it will be almost impossible to do this. In such a situation, it is wiser, according to the "antibembists", to completely abandon large-scale projects to relocate reindeer from one country to another - at least until a vaccine or medicine for CWD appears.

N + 1 sent a letter to the Ministry of Natural Resources with questions about the project for the resettlement of white-tailed deer in Russia - and received an answer according to which it is planned to use not Finnish animals for this, but those that have already been brought into our country from the USA and Canada and are kept in aviaries.

It is possible that some of them are carriers of an infectious form of chronic wasting disease, but we do not know about this yet. The quarantine that the reindeer go through before they get to Russia does not last long enough to exclude the importation of the infection - “zombie” symptoms can appear in a few months or a year after infection. Specialized tests could solve the problem, but now they are not formally required. And the breeders themselves rarely use such tests - it's expensive. Moreover, having found sick and dead deer in the enclosures, the owners of hunting farms may not attach due importance to this - or even hide this information in order to avoid the destruction of the entire livestock.

At the same time, we do not conduct the same careful monitoring of the health status of wild and semi-free deer and elk, as in Scandinavia. Thus, the ministry informed N + 1 about the only case of testing white-tailed deer for CWD - tests were carried out on 3.5 percent of the semi-free herd brought from Canada to the Smolensk region.

Thus, the risk of a bambi apocalypse in Russia is already there - but it can grow if the full-fledged acclimatization of white-tailed deer still starts. The draft law, proposed by the Ministry of Natural Resources, received a sharply negative assessment from specialists and several dozen negative responses on the regulation.gov.ru website. The department did not give an answer to the N + 1 question about whether it is planned to amend or revoke the bill.

Popular by topic