This summer, residents of the capital region began to notice huge and voracious slugs in dacha plots and natural areas more and more often. Biologists suggest that red Spanish slugs (as this mollusk is called) may have been inadvertently introduced from southern countries along with fruits and vegetables.
On the territory of Russia there are more than a thousand “alien” plant and animal species. What are the reasons for the appearance of invasive species (in the language of science — invasive species) and what do they threaten us with? aif.ru talks about this with chief researcher at the Institute of Ecology and Evolution im. A. N. Severtsov RAS, Doctor of Biological Sciences Varos Petrosyan.
Dmitry Pisarenko, aif.ru: Where and how do these strangers arrive in Russia?
Varos Petrosyan: Native (native) ranges of invasive species are located on all continents except Antarctica. But the birthplace of the majority — North America. A few years ago, we with colleagues from other institutions compiled a list of 100 invasive species that pose the greatest threat to the ecosystems and health of the population of Russia. The main way they arrived in our country — shipping. Mollusks, crustaceans come with ballast water of ships or on their hulls. There are deliveries with cultural plants, agricultural products. The analysis shows that most of the most dangerous species (63%) entered our ecosystems by accident. A third (33%) appeared here intentionally — they brought to increase biodiversity, breeding, etc. n. Only 4% of species were dominated by self-dispersal.
What is the danger of alien species? The consequences of their appearance are little predictable. Often they crowd out local (native) species, cause environmental and economic damage, spread diseases, including those that can be transferred to humans. Experts estimate the total damage to the country from the ten most dangerous invasive species of mammals at $105 billion annually.
— Which species has turned out to be the most harmful and dangerous for the last decades?
— Comb jelly Mnemiopsis. It looks like jellyfish, although it is not 40 years ago, Mnemiopsis was first discovered off the coast of Crimea. Genetic analysis showed that he introduced into the Black Sea from the Gulf of Mexico, apparently with ballast water from ships. For our southern seas, it has become a real disaster. In the absence of natural enemies, he began to multiply rapidly, consuming zooplankton, caviar and fish larvae. Under favorable conditions, it can eat ten times its own weight per day and double its size, laying up to 8 thousands of eggs. eggs. As a result, the amount of food for fish (zooplankton) in the Black Sea has decreased by 30 times. The number of anchovy, horse mackerel and sprat has dropped dozens of times. Fishing losses amounted to hundreds of millions of dollars a year. The Black Sea dolphins also ended up on starvation rations.
Later, the comb jelly entered the Caspian Sea, where it caused even more damage. There, the population of kilka sharply decreased, and then sturgeon. The lack of fish led to the mass death of the Caspian seal. In addition, Mnemiopsis clogs fishing nets and interferes with coastal fishing.
Comb jelly Mnemiopsis. Photo: Commons.wikimedia.org/Steven G. Johnson
— A on on onshore who is the main alien pest?
— All invasive insects. In recent years, a lot of them have penetrated Russian forests. This, for example, is the Ussuri polygraph that damages fir and other coniferous trees. In the 20th century, it settled throughout Siberia, and then it was found in the Leningrad and Moscow regions and even in the Main Botanical Garden of the Russian Academy of Sciences. Ash narrow-bodied emerald borer causes damage to ash, which has become a threat to both landscaping and the country's forestry.
The database contains 62 dangerous invasive species of mammals. The Canadian beaver deserves special attention. It looks like the usual (river) beaver — it has the same way of life, yet these are two different species. The Canadian beaver came to us from Finland, where it was brought from America, and dispersed further through Karelia. Now both species live in Russia, but the Canadian one is replacing the river one everywhere. He is more prolific.
It would seem, what difference does it make if they are similar? But the fact is that the Canadian beaver breeds faster and has a bad effect on aquatic and water ecosystems: new swamps appear, spruce forests dry up due to the built dams, the hydrological regime, flora and fauna change. This animal will create uncomfortable conditions in cities — destroy trees in & nbsp; parks, create dams. In America, they gnaw away wooden bridges and pillars on which buildings stand. There was news that in Canada, a beaver gnawed through a fiber optic cable and left the inhabitants of a village without the Internet. In ten years, and the same thing threatens us. Mathematical models show that this species will spread and expand its range. Yes beavers have already appeared in the Moscow region. Unfortunately, work related to regulation of the beaver population in Russia is practically not carried out now.
Canadian beaver. Photo: Commons.wikimedia.org/LASZLO ILYES (laszlo-photo) from Cleveland, Ohio, USA
Mouse runs from drought
— It is generally accepted that the expansion of ranges is associated with climate changes: the warmer, the more moving northward, say, tropical species. Is that right?
— Indeed, global warming is making itself felt. Scientists associate the increase in invasions around the world, including with it. A year ago, the UN published the next, sixth in a row, report on what is happening with climate on the planet. Warming is proceeding at an unprecedented rate, changes are taking place in nature, which have not happened for hundreds of thousands of years. This report presents 40 models in different regions of the Earth. Until 2040, all these models are quite close and show a warming of 1.5 °C. But further, until 2100 years, the scenarios differ, the range of possible warming ranges from 4.6 to 6°C.
Using these climatic models, we studied two biological species that are invasive and are of great importance for Russian agriculture, as they affect the yield of grain crops and potatoes. This is a field mouse and a golden potato nematode, both are pests. We analyzed how their areas are changing in recent times, and made a forecast. All over the world, in connection with warming, the ranges of species are shifting from south to north (in the opposite is true in the Southern Hemisphere), but in Russia simultaneously with their movement from west to east, and this speed twice as high. And if now the range of the field mouse has a gap between Baikal and the Far East, then soon its two parts will unite. The last time this was 12 & nbsp; thousand. years ago.
— And what does it mean? It seems the mouse — not so scary.
— First of all, she is far from so harmless. In addition to being one of the main pests of grain crops, it also carries a lot of infection, about 15 infectious diseases. Field Mice — the main source of human infection with hemorrhagic fever with renal syndrome, often fatal.
Secondly, and most importantly, our study shows that land use will have to change nationwide: where wheat and potatoes grow now, they will stop growing already, perhaps by 2040 . The ranges of these species are not expanding as much as they are shifting. Field Mouse — the most moisture-loving species among mouse-like rodents. She runs away from where it gets dry. In & nbsp; the southern regions, which now provide the main crop of cereals and & nbsp; potatoes, in 20 years there will be unsuitable climatic conditions for this. The temperature in summer there will reach up to & nbsp; 47-50 ° C, moisture will instantly evaporate, and soil — crack from the heat. This process is called aridization, and it will capture the entire south of the European part of Russia. You need to think about this already now.
— Will appear we in exotic species in the middle lane? For example, some black mamba in the meshchera forests or a crocodile in the Volga?
— Natural conditions are becoming more and more suitable for this, and a poisonous snake and can now escape from some terrarium. global warming has another manifestation — diurnal temperature fluctuations are reduced. That is, the difference between the temperature during the day and night is reduced: for example, during the day — 35 °C, and at night — 31°C. And such small differences just contribute to the survival of tropical species, it is easier for them to adapt.
Crocodiles in Russian rivers — this, of course, sounds like a fantasy, but in a hundred years this will be possible.
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