Positive and negative effects of humans on animals: examples. R&D: Human influence on the animal world
The extinction of some and the emergence of other animal species is inevitable and natural. This happens in the course of evolution, with changes in climatic conditions, landscapes, as a result of competitive relationships. V natural conditions this process is slow. According to D. Fisher's calculations (1976), before the appearance of man on Earth average duration the life of the bird species was about 2 million years, of mammals - about 600 thousand years. Man hastened the death of many species.
Human economic activity strongly affects animals, causing an increase in the number of some, a decrease in the populations of others, and the extinction of others. Human exposure to animals can be direct or indirect.
Direct impact(persecution, extermination and resettlement) are experienced mainly by game animals, which are hunted for fur, meat, fat, etc. As a result, their number decreases, and some species disappear.
Direct exposure includes introduction and acclimatization animals to new areas. Along with purposeful resettlement, cases of unintentional, spontaneous importation of some, often harmful animals to new, sometimes distant places, are quite common.
Indirect influence man on animals is associated with a change in the habitat during deforestation, plowing of steppes, drainage of swamps, construction of dams, construction of cities, villages, roads, with changes in vegetation as a result of pollution of the atmosphere, water, soil, etc. This radically changes the natural landscapes and living conditions of animals.
Most animal species cannot adapt to human-changed conditions; they either move to new places or die.
The shallowing of rivers, drainage of swamps and floodplain lakes, and a reduction in the area of sea estuaries suitable for nesting, molting and wintering of waterfowl caused a sharp decline in their natural reserves. The negative impact of humans on animals is growing in scale. To date, about 150 species and subspecies of birds have disappeared in the world. According to the IUCN, one species (or one species) of vertebrates perishes annually. More than 600 species of birds and about 120 species of mammals, many species of fish, amphibians, reptiles, mollusks, insects are in danger of extinction.
2.3. Animal protection
Protection of aquatic invertebrates. Marine and freshwater animals - sponges lead an attached lifestyle, form colonies in areas with hard rocky soil. To preserve the role of sponges as biofilters, it is necessary to reduce their fishing, use fishing gear that does not harm aquatic ecosystems, and reduce the intake of various pollutants into water bodies.
Coral polyps - marine colonial organisms. Of particular interest is the order of madrepore corals - the most extensive group of the coelenterates type.
Shellfish - a type of marine and freshwater, less often terrestrial invertebrates, which are characterized by a hard calcareous shell covering the body. Molluscs serve as food for fish, birds and mammals. They have nutritional value for humans as well. Oysters, mussels, scallops, squid, cuttlefish, octopuses are harvested. There is a fishery for pearl oysters and nacreous shells.
Crustaceans - animals, different in lifestyle, body shape and size (from fractions of a millimeter to 80 cm).
Crustaceans play important role in aquatic ecosystems, they act as intermediaries between algae and fish, making the organic matter created by the algae available to fish. On the other hand, they use dead animals for food, ensuring the purity of the reservoir.
Pollinating insects pollinate about 80% of all flowering plants. The absence of pollinating insects changes the appearance of the vegetation cover. In addition to the honey bee (the income from pollination of plants with it is 10-12 times higher than the income from honey and wax), 20 thousand species of wild bees carry pollen (of which 300 - in central Russia and 120 - in Central Asia). Bumblebees, flies, butterflies, beetles participate in pollination.
Are of great benefit different types ground beetles, lacewings, ladybirds and other insects, exterminating pests of agricultural and forest plants.
Insect orderlies belong to the family of beetles and dipterans. These are widespread groups of dead eaters, dung beetles, kaloedov and flies, numbering thousands of species.
Fish protection. In human protein nutrition, fish make up from 17 to 83%. World fish catches are rapidly increasing due to the development of the edge of the continental shelf and the depths of the open sea, where up to 85% of fish are now caught, including new commercial species. The permissible annual withdrawal of fish from the World Ocean is estimated at 80-100 million tons, of which more than 70% is now caught. In the inland waters of most countries, including Russia, the fish catch has reached its limit, has stabilized or decreased.
Overfishing - a phenomenon common in many marine and inland waters. At the same time, young fish that have not reached sexual maturity are caught, which reduces the population size and can lead to the extinction of the species. Fighting overfishing is the most important task of fisheries, protection and rational use of fish resources.
Water pollution negatively affects the state of fish stocks. Pollution of marine and freshwater bodies of various substances has become widespread and continues to increase. Particularly dangerous for fish are pollution by industrial wastewater containing salts of heavy metals, synthetic detergents, radioactive waste and oil.
Hydraulic structures render bad influence on the number of fish. Dams on rivers block the access of migratory fish to spawning grounds and disrupt natural reproduction. A number of measures are taken to eliminate this adverse effect.
Shallowing rivers reduces fish stocks. It is associated with deforestation of banks and watersheds, with water withdrawal for irrigation. Measures have been developed to raise the water level in rivers and inland seas, which is of great importance for fisheries, agriculture, climate mitigation, etc. One of the cardinal measures is coastal afforestation, which requires constant care for a long time.
Protection of amphibians and reptiles. These two groups of animals have a small number of species (amphibians - 4500, reptiles - 7000), but their importance in natural biocenoses is very high. Amphibians are carnivores, and there are herbivorous species among reptiles.
Amphibians, feeding on insects and other invertebrates, regulate their numbers and, in turn, are food for reptiles, birds and mammals. Some amphibians (giant salamander, pond, edible, Chinese frogs, bullfrog, etc.) are eaten by humans; amphibians are widely used in laboratories for biological experiments.
Reptiles, no less than other groups of animals, suffer from overhunting. Great damage was done to populations of game reptiles: crocodiles, turtles, monitor lizards and some snakes. Turtles and their clutches are used for food in many tropical countries.
Protection and attraction of birds. The very important importance of birds in the national economy (except for poultry farming) is explained by their participation in the extermination of pests in forestry and agriculture. Most bird species are insectivorous and herbivorous insectivores. During the nesting period, they feed their chicks. mass species insects, among which there are many pests. To combat insect pests, birds are attracted by hanging feeders and artificial nests. Hollow nests deserve special attention: tits, flycatchers, wagtails, which use artificial nests more often than others.
Protection of mammals. Representatives of the class of mammals, or animals, are important to humans. Breeding of ungulates is the basis of animal husbandry; rodents and carnivores are used in fur farming. The most important for the fishery are of the terrestrial ones - rodents, lagomorphs, carnivores, and of the aquatic ones - cetaceans and seals.
All of these measures are aimed at the protection and rational use of mammals. Recently, more attention has been paid to the protection of wild animals. 245 species of mammals live on the territory of Russia, of which 65 species are included in the Red Book of the Russian Federation.
Especially in the last few centuries of the existence of modern mankind, of course, it is one of the most powerful factors that transform animals, for example, both positive and negative, has acquired such a large-scale character in the 21st century that we can talk about a direct dependence of the survival of some species on further functioning of civilization.
Ancient times: hunters
Even during the Upper Paleolithic, people began to hunt. In those days, the influence of people on animals was mainly in the extermination of species that are already extinct today, such as the mammoth or woolly rhinoceros (their remains were found during excavations at human sites of that time). The then production: animals, fish, birds - gave people protein food, provided materials for shoes and clothes, some household items. Dwellings were built from skins, bones and tusks during the last ice age. As some researchers point out, at that time people lived in small communities of 100-150 members. The clan was headed by the most respected elders, and property, including food supplies and dwellings, was shared. Enough cold climate led to an urgent need for clothing and to a certain primitive modernization of the dwelling. So, the skins of killed and eaten animals were cut into pieces, and holes made of stone were punched along the edges with needles, then everything was sewn together with elongated veins. According to studies, one of the common then was the use of the bones of a mammoth or other large animal as building material for settlements. A not too deep oval or round pit was dug. Along the edge of the pit, ribs protruding into the interior were driven in. This whole structure was covered or sheathed with skins, covered with branches and covered with earth.
Farmers and pastoralists
The use of meat for food led, according to F. Engels, to the fact that people learned to use fire for its heat treatment and domesticated some species of animals (so as not to hunt, but to have a meat base always at hand). With the improvement of techniques and tools of labor and hunting, the influence of people on animals and the environment also increased. It was expressed in a rather multifaceted way: both in the direct destruction of wild species used as food, and in the domestication of some representatives, and indirectly, in a change in the plant base that preceded the emergence and spread of agriculture. And with the transition to a pastoralist lifestyle and agriculture (in the Neolithic era), the influence of people on animals acquired new forms and realities. And its methods have become more complicated and expanded.
Indirect human influence on animals
As agriculture spread, people used more and more spaces for planting and harvesting. This, in particular, increased the indirect influence of man on animals. Destroyed natural environments habitat: forests were cut down and meadows and fields were cultivated, which led to the redistribution and even extinction of some species of the animal world and, conversely, the introduction of others.
Fishing
A huge negative influence of man on animals, which led to the almost complete disappearance or significant reduction of some populations and species, was exerted by the development of crafts - organized hunting of animals in order to obtain, for example, fur. So in the 16th century (this became known thanks to the research of the historian Karamzin), the Sovereign of Muscovy, after the conquest of Siberia, imposed the so-called yasaka on the representatives of the nationalities living there: 200 thousand sable skins, 500 thousand squirrels, 10 thousand foxes! Such was the price of the issue of fishing, which had a huge human influence on animal world in this period!
Extermination of whales
The hunt for these water giants was born a long time ago. In the beginning, people used the carcasses of whales that they washed ashore. Then, in the eyes of the ancient hunters, this mountain of meat and fat became not only desirable, but also very accessible. After all, a whale is a slow-moving creature, and if desired, it could be caught up even on a simple sailless boat. Simple harpoon weapons and ropes were suitable for its extraction. In addition, the dead man did not drown in the water, which was also an important factor for the hunters. Pomors hunted whales for a long time, but the global extermination of the species began in the 17th century. Then the population was so numerous that ships traveling to Spitsbergen had to literally push their herds apart by the sides. In those days, the Dutch, Danes, Germans, British, French and Spaniards sent up to 1000 ships a year to fishing every year! And according to researchers of the issue, the annual production of whales, for example, in the 18th century already amounted to more than 2.5 thousand annually. It is not surprising that the reserves of huge mammals were depleted, and by the end of the 19th century, this species was put on the brink of extinction by man! And in 1935 g. International commission establishes a ban on fishing for bowhead whales.
More examples
It was Negative influence man on animals. Other examples can be cited: deforestation of the Amazon, drying up of the Aral Sea, complete disappearance due to human fault of some species of mammals (steppe kangaroo rat, pig-footed bandicoot, red-bellied possum, Yemeni gazelle, Madagascar pygmy hippopotamus, marsupial wolf - and more than 27 in the last century alone). It is believed that since 1600, at least 160 subspecies and species of birds have been exterminated by mankind, more than 100 mammals. Such is the fate, for example, of bison and rounds, tarpans, and people decided for them.
Economic activity of people
Human activities, not related to fishing and hunting, today have a huge impact on the animal world. So, for example, the development of a territory within the habitat of an animal and, as a result, a reduction in the food supply, can cause a decrease in the population and the subsequent disappearance of a certain species. A striking example is a significant decrease in the number of And in the oceans in the nets intended for catching fish, dolphins die every year - tens of thousands! After all, they cannot get out, entangled, and suffocate. And more recently, the scale of death of dolphin flocks reached 100,000 per year.
Environmental pollution
In recent years, this is one of the most important negative factors of human influence on the animal world. Radioactive contamination, on land, harmful emissions in aquatic environment and the atmosphere - all this leads to a decrease in the number of animals and reduces species diversity on the planet.
The positive impact of humans on animals
To be honest, on many points people realized it quite late. Many species of animals in the modern world are on the verge of extinction, and some have completely disappeared into oblivion. But one thing is good that at least in the 21st century, quite a lot of attention is paid to the protection the environment protecting the endangered animal world. Reserves, wildlife sanctuaries and national parks are being created, where people are trying to restore what they have lost. And not in vain, after all, according to the forecasts of some scientists, if humanity does not stop and continues its destructive activity on a planetary scale, then this can lead to a sad and imminent end (some give less than 50 years) of all life on Earth.
The extinction of some and the emergence of other animal species occurs during evolution, with changes in climatic conditions, landscapes, as a result of competitive relationships. Under natural conditions, this process is slow. According to D. Fisher's calculations 11976), before the appearance of man on Earth, the average life span of birds was about 2 million years, mammals - about 600 thousand years. Man hastened the death of many species. He markedly influenced animals already in the Paleolithic, more than 250 thousand years ago, when he mastered fire. Large animals were his first victims. In Europe, as early as 100 thousand years ago, man contributed to the extinction of the forest elephant, forest chough, giant deer, woolly rhinoceros and mammoth. In North America, about 3 thousand years ago, apparently not without human influence, a mastodon, a giant llama, a black-toothed cat, and a huge stork died out. The island fauna turned out to be the most vulnerable. Before the appearance of Europeans in New Zealand, the Maori, local residents, had exterminated more than 20 species of huge moa birds. The early period of the destruction of animals by man received the name "Pleistocene overhunting" from archaeologists. Since 1600, the extinction of species has been documented. Since that time, according to The International Union Conservation of nature (IUCN), 94 species (1.09%) of birds and 63 species (1.48%) of mammals became extinct on Earth. The death of more than 75% of mammalian species and 86% of birds from the above number is associated with human activities.
Human economic activity strongly affects animals, causing an increase in the number of some, a decrease in the populations of others, and the extinction of others. Human exposure to animals can be direct or indirect.
The direct impact (persecution, extermination and resettlement) is experienced mainly by game animals, which are hunted for fur, meat, fat, etc. As a result, their number decreases, and certain species disappear.
Relocation of animals from other areas is widely practiced to combat pests of agricultural and forest plants. At the same time, it is not uncommon for displaced persons to have a negative impact on the new habitat. For example, the mongoose, brought to the Antilles to control rodents, began to harm birds nesting on the ground and became a distributor of rabies. New species of animals were introduced and acclimatized to many countries and continents with the active or passive participation of humans. They began to play an important role in the life of local nature and people. Especially many new species were introduced to Australia, New Zealand and to the oceanic islands during the period of mass migration of Europeans to these then not yet inhabited countries. In New Zealand, with its poor fauna, 31 species of birds, 34 species of mammals, several species of fish imported from Europe, Asia, Australia, America, Polynesia have taken root.
In the former Soviet republics, work was carried out to acclimatize more than 137 species of animals. According to incomplete data, 10 species of insects, 5 species of fish and 5 species of mammals have been introduced into the fauna.
The unintentional, accidental dispersal of animals has especially increased in connection with the development of transport, delivering them to various regions of the world. For example, when inspecting aircraft at airports in the United States and Hawaii in 1952-1961. 50 thousand species of insects were discovered. A special quarantine service has been introduced in commercial ports to prevent accidental import of animals
Direct human impacts on animals include their death from chemicals used to control agricultural pests and weeds. At the same time, not only pests, but also animals useful to humans, often perish. Numerous facts of poisoning of fish and other animals with fertilizers and poisonous substances should be attributed to the same cases. Wastewater discharged by industrial and household enterprises.
The indirect influence of humans on animals is associated with a change in the habitat (when deforestation, plowing steppes, draining swamps, building dams, building cities, villages, roads) and vegetation (as a result of pollution of the atmosphere, water, soil, etc.), when the natural landscapes and living conditions of animals are radically transformed.
Some species in the changed environment find favorable conditions for themselves and expand their range. House and field sparrows, for example, along with the advancement of agriculture to the north and east of the forest zone, penetrated into the tundra and reached the coast The Pacific... Following the deforestation, the appearance of fields and meadows, the habitats of the lark, lapwing, starling, and rook moved to the north, to the taiga zone.
Under the influence economic activity new anthropogenic landscapes emerged with specific fauna... The most changed are the urbanized territories occupied by cities and industrial agglomerations. Some species of animals have found favorable conditions in anthropogenic landscapes. Even in the taiga zone, house and field sparrows, village and city swallows, jackdaws, rooks, house mouse, gray rat, some types of insects. The fauna of anthropogenic landscapes has a small number of species and a high density of animal populations.
Most animal species, not adapting to the conditions changed by man, move to new places or die. With the deterioration of living conditions under the influence of human economic activity, many types of natural landscapes reduce their numbers. Baibak (Marmota bobak), a typical inhabitant of virgin steppes, in the past was widespread in the steppe regions of the European part of Russia. As the steppes were plowed, its number decreased, and now it has survived only in some areas. Together with the marmot, the sheath duck disappeared from the steppes, which nested in marmot holes, and now has lost its nesting sites. Cultivation of the land had a negative impact on other indigenous inhabitants of the virgin steppe - bustard and little bustard. In the past, they were numerous in the steppes of Europe, Kazakhstan, Western Siberia, Transbaikalia and Priamurye, are now preserved in not a large number only in Kazakhstan and in the south of Western Siberia. Shallowing of rivers, drainage of swamps and floodplain lakes, reduction of the area of sea estuaries suitable for nesting, molting and wintering of waterfowl, caused a sharp decline in their species. The negative impact of humans on animals is growing in scale. To date, about 150 species and subspecies of birds have disappeared in the world. According to the IUCN, one species (or subspecies) of vertebrates die every year. More than 600 species of birds and about 120 species of mammals, many species of fish, amphibians, reptiles, mollusks, and insects are in danger of extinction.
The main and most ancient types of human impact on the animal world are hunting and trades.
The direct impact of man on the animal world began in ancient times with hunting for food, clothing, that is, as an organic necessity. With the improvement of hunting tools in a number of places, the number of certain species of animals began to decrease noticeably. With the advent of firearms and with the development of technology, hunting began to take on destructive proportions. So, for 27 years on the Commander Islands, the Steller's cow, an endemic of these places, has completely disappeared; in a short time, a wandering pigeon was exterminated in North America, the wingless auk disappeared, etc.
In 1604, Bennett started the walrus industry for their tusks. The extermination of walruses quickly swept the Spitsbergen archipelago and began to move further east. On Medvezhye Island alone in 1667, 900 walruses were killed in a few hours, and the carcasses were thrown, although the meat, fat and skin could be used. In 1923, more than a thousand walrus carcasses without tusks were nailed to the shores of Cape Barrow in Alaska. The extermination of sea otters (sea otters) began in 1778 with James Cook's voyage off the western shores of North America. These defenseless animals were beaten with sticks in rookeries for their skins. On the Pribylov Islands in 1786, two people killed 5000 sea otters.
Poaching with cars, machine guns and submachine guns for saigas, gazelles, bustards in Asia, antelopes and zebras in Africa has led to a sharp reduction in the number of many species of wild ungulates. Of all African animals, elephants and rhinoceroses have undergone the greatest extermination. In 1920-1930. about 41 thousand elephants were killed annually. In 1957, 12.6 tons of ivory and 1,280 abandoned elephant carcasses were found in Tsavo National Park in Kenya during an anti-poaching campaign, and 230 kg of rhino horns were confiscated. By 1980, despite the prohibitions, poachers in Africa kill 60–70 thousand elephants annually for ivory, and thousands of tons of edible meat are usually thrown away.
It does not fit into the framework of elementary human morality to conduct such safaris in Africa as wild mass shootings of animals, after which the proud "hero" was photographed against the background of a mountain of animals he had killed or trampling on heaps of his victims.
How can you qualify the organizers and participants of the raid in the Isère department in France in 1954, when 5 police brigades, 3,000 hunters and one helicopter took up arms against one she-wolf with two wolf cubs? And how can you call the show of a certain Cody named Buffalo Bill, who, in front of the audience, from a specially arrived train, together with another shooter, drove along the prairie and shot buffaloes to the admiring cries of the staring crowd! On that day, 115 animals were killed for the needs of the public. The construction of a transcontinental railroad in the United States led to the rapid and almost complete extermination of animals. Railway stations temporarily became centers of wild hunting, for example, in the area of the village of Dodge City, in 1873 alone, 75 thousand bison were killed, and in 6 years - 2.5 million heads.
Unfortunately the story human civilization from antiquity to our time, it is replete with events that do not adorn man at all.
So from ancient hunting as a means for obtaining the necessary food and clothing with the development of technology and civilization, two main directions gradually emerged: "sport hunting" and fishing.
"Sport hunting", in essence, is a deliberate murder, sometimes for the purpose of deliberate regulation of the number of a particular species, but more often for the sake of self-assertion, vanity, or to satisfy the bloodthirsty instincts of the person himself.
Another direction of hunting is also developing - hunting: whaling, sea animals, fur, fishing, etc. Although this direction in the extermination of animals has practical goals related to meeting human needs, the widespread introduction of modern technology has led to a sharp decline in the populations of animals that have become the object this trade. For example, the introduction of a motorized whaling fleet resulted in the deaths of most of the smooth whales and brought the species of large minke whales to the brink of extinction.
Satisfaction of human needs is a conditional concept, because needs border on whim and sometimes pass into it imperceptibly. For example, the mass harvesting of chum salmon or pressed caviar is probably not generated by a vital human need and, although it does not seem to be a direct killing of animals, it leads to a sharp reduction in the breeding opportunities of this species. And a number of species from the salmon family (chum salmon, pink salmon, salmon, whitefish, etc.) belong to commercial fish, since their representatives have tasty and nutritious meat. This begs the question: which direction of fishing is more rational - the extraction of caviar or fish meat, given that tens of thousands of fish could hatch from each kilogram of caviar, each of which would yield several kilograms of pure meat? Obviously, when solving the issue of fishing, since at the modern level of development of consciousness, humanity is not yet ready to give up food of animal origin and use different types animal raw materials on the farm, it is necessary to consider the possibilities of the most complete rational and cost-effective use game animals.
In this regard, let us return to the whaling industry. The bowhead whale was used most fully by humans. Whale oil was used as food, used to illuminate streets and homes, in soap and leather production. After heat treatment (hot water or steam), the whalebone became suitable for stamping and acquired great strength that is why cases, canes, handles, rods, springs for carriages and mattresses were made from whalebone plates; fans, bandages, prostheses, knitting needles for umbrellas, plates for corsets, standing collars and crinolines were made from thin plates; from the best varieties plates made clock springs; from the fringe and fibers of the middle layer, wigs, brushes, sieves and fishing lines were made. Whales were especially fully used by northern peoples (Eskimos, Chukchi, Aleuts, etc.): fat, meat and part of the entrails were used as food for people and dogs, waterproof clothing and containers for storing fat were made from the intestines; boats were sewn with sinews and ropes were twisted from them; sledges were knocked out with a whalebone, from which bows, shovels, pikes, harpoons and thin spirals were made for laying in meat baits when hunting bears and wolves; stools were made from the vertebrae; from ribs and jaws they built dwellings and fences, made frames for kayaks (light boats), etc.
Now many countries are abandoning whale fishing. For example, in the United States in 1972 a law was passed prohibiting the citizens of this country not only from killing a sea animal, but even being present when someone kills it. Despite the refusal of a number of countries from whaling, in general, the globe Whalers kill tens of thousands of whales of all kinds every year, and in most cases the use of whales is very incomplete compared to bowhead whales. Professor A.V. Yablokov believes that it is more profitable for us to go to shepherding - not to send a flotilla to distant lands, which will beat everything that it gets, but to graze a herd of 50 or even 30 whales, know all of them by their nicknames, character and age, and when this the whale will turn, say, 30 years old, it will come out of reproductive age and it will not be harmful for the whole herd to slaughter it. By this time, it will be possible to prepare canning factories and get so many products that it will provide the entire Magadan region with whale meat and fat, for example, for 3-4 months. This is much more profitable than fishing, in which the products are inevitably far from being fully utilized.
Ridiculous fashion fads are driving demand for a whole range of animal products. The fashion for ostrich feathers on ladies' hats at the beginning of the century can hardly be attributed to the urgent needs of man, which led to the mass extermination of ostriches. The same order applies to the fashion for handbags, reticules, wallets, shoes and other products made of snake or crocodile skin. Tanneries process 2 million crocodile skins annually, and as a result, several species of crocodiles are endangered; a trendy South American ocelot coat, for which 10 animals are killed, costs as much as three Mercedes cars; predatory extermination of this animal has led to a sharp decline in its population. The population has decreased significantly marsupial bear koala in Australia due womens fashion throw his fur over his shoulders. All this is generated not by needs, but by the whims of a person.
"Harmful" animals: often it turns out to be controversial and even erroneous assessment of the "harmfulness" of this or that animal, because in such an assessment, much is relative.
The wild boar, from the point of view of farmers, is a harmful animal, since it causes damage by its forays into the fields of potatoes or oats, but the wild boar is useful for forestry, since, in addition to plant food, it destroys a number of forest pests, which has a positive effect on the condition of trees.
The history of man's relationship to birds of prey is interesting. In ancient times and the Middle Ages, people took care of birds of prey and loved them. In England and Denmark, for killing a falcon, a person could get to the executioner. Then birds of prey were declared harmful and began to exterminate them. So, for example, in 1962 more than a million "harmful" birds were destroyed in the USSR. And out of 46 species of daytime predators in our country, only two (goshawk and marsh harrier) destroy game, and even then mainly sick and weak birds, thereby making their populations healthy. In addition, it should be borne in mind that many birds and rodents eaten by birds of prey are carriers of serious diseases - plague, encephalitis, tularemia, leptospirosis, ornithosis, etc. Therefore, birds of prey are not enemies, but friends of man. Only on 1.08.64 was the order No. 173 of the Main Directorate of Hunting Economy and Reserves issued: “Given the new data on the biology of birds of prey and the significant benefits they bring in agriculture, hunting, forestry and health care, I order: prohibit shooting, trapping and ruining nests all kinds of birds of prey and owls in hunting grounds common use throughout the territory of the RSFSR ".
Long time it was considered a harmful animal of the wolf for the cases of its attack on sheep and other domestic animals. But the wolf more often hunts for wild animals - deer, roe deer, making their populations healthier, since relatively weak and sick animals are usually its prey.
A similar situation developed in Australia with respect to the wild dingo dog, which cattle breeders have long considered harmful and exterminated by all possible means. However, for recent times more and more farmers are convinced that the dingo, pursuing a flock of sheep, is a stimulator of their best physical development: Sheep, often hunted by dingoes, develop muscles with less fat, their meat is more appreciated by consumers and turns out to be economically profitable for farmers. On the other hand, dingoes are a vehicle for the selection of weak, sick and inferior sheep and, ultimately, for the health of the flock. Therefore, more and more farmers are abandoning the pursuit of dingoes.
Giant red kangaroos living on the plains of Australia began to multiply rapidly under the influence of human economic activities. These animals are not picky about the weather, they can go without water for a long time. In areas where farmers have created extensive grazing for livestock, the kangaroo population began to increase rapidly, so that now there are 4 kangaroos per person in Australia. The kangaroo invasion of pastures and fields forced farmers to carry out extermination raids on their herds. The German zoologist B. Grzimek, who studied the Australian fauna, suggests not to exterminate, but to breed a kangaroo and use its meat in the food industry, since in terms of nutritional value it is in no way inferior to the meat of antelopes, deer and saigas. Thus, an animal from “harmful” can turn into a useful one for humans.
The usual attitude towards the fox is a harmful animal that climbs into village chicken coops, exterminates many birds, hares and other animals in the forest. Prof. A. Gaber found only the remains of mice in 70% of the stomachs of a large number of foxes killed by the hunters.
An instructive story happened with the sparrows in China. Since sparrows willingly eat grain, they were declared enemy number one and a nationwide struggle was organized with them. Tens of millions of people went out into the fields, chasing the sparrows, not allowing them to sit down. Many birds fell dead, they were immediately loaded into trucks and taken away. There were no sparrows. Soon, the number of flies, mosquitoes and many other insects, which the sparrows ate and thus restrained their reproduction, increased sharply. Only after the destruction of the sparrows was it found that they did more good than harm. Bad experience.
Chemical effects on animals can be direct - when purposefully exterminated certain kind an animal that is considered "harmful", and indirect - when there is an unprogrammed effect of pesticides on animals against which they were not intended, as well as when anthropogenic substances harmful to animals enter the biosphere. Both types of exposure are often closely intertwined with each other.
In 1874, the German Zeidler invented a powder, the effect of which on insects was investigated in 1937 by the Swiss chemist P. Müller, who received the Nobel Prize for this. By the end of World War II, this powder, called DDT in the United States (and in our country known as dust), began to be used in the army against lice, fleas, bedbugs and other insects. After the war, DDT became widespread throughout the world: it was mixed into lime, sprayed with it on the walls of premises, and it was pollinated from planes in forests and swamps where mosquitoes were found. Enormous quantities of it began to be produced and used against agricultural pests. But already in 1947, insects began to appear, on which this powder did not work. A number of new pesticides were released, which, instead of DDT, began to be sprayed in increasing quantities. Some of the consequences were unexpected. In the course of the destruction of insect pests, beneficial insects also began to disappear. Trees pollinated by insects ceased to bear fruit, insectivorous birds and fish died in masses, having lost their food in the form of insects and mosquito larvae. In many areas, beneficial insects began to die, while harmful ones survived: bees immediately die from DDT, but it does not work on the Colorado potato beetle and the cabbage butterfly.
However, the use of pesticides is growing rapidly. So, for the period from 1950 to 1967, the use of pesticides in agriculture increased 3 times in the United States, and 22 times in Japan. At the same time, the arsenal of chemical agents for influencing the biosphere is growing and a group of chemical agents “pesticides” appears - highly active toxic substances. They include: insecticides (means to kill harmful insects), rodenticides (to control rodents), bactericides (to kill bacteria that cause diseases of cultivated plants), herbicides (to kill weeds), fungicides (to combat pathogens of fungal diseases) ... The massive use of pesticides is due to the fact that every year a significant part of the crop yield is killed by insects, rodents and other pests. By 1975, the amount of grain losses reached 85 million tons per year, which could feed 380 million people. Hence, the desire of scientists to find radical means of combating agricultural pests is understandable.
The massive use of pesticides is accompanied by an increase in unprogrammed negative consequences... So, in 1960 in the Netherlands, after using parathion against rodents, hundreds of thousands of birds died. Similar consequences existed in France, the USA and other countries: after mass spraying, at least 30% of local birds died. In a number of countries Western Europe after spraying the gardens, hares began to disappear, in the spring they ate grass near the trunks of treated trees, which had been poisoned. In the California Valley, pesticides were used to kill ligus, an insect that caused enormous damage to cotton plantations. However, by the end of the season, scoops, box worms, heliotis, and other cotton pests, multiplied excessively on the plantations they treated, since pesticides with a wide spectrum of action destroyed not only ligus, but also natural enemies pests. There are many such examples.
In 1962, Dr. R. Carson's book "Silent Spring" appeared, in which she published data on the special persistence of pesticides, their ability to concentrate in food and organisms. The concentration of pesticides in the soil was ten times higher than when sprayed. The alarmed public prompted the President of the United States to create a special committee to study the effects of pesticides on nature. In 1963, the committee presented a report in which it noted, on the one hand, the great advantages of these products for the control of agricultural pests, and on the other, that pesticides can be transported over great distances by wind, water and animals: they can be found in whale oil. , in meat sea fish, in the organisms of Antarctic penguins.
Over the years, the massive use of pesticides began to be accompanied by more and more frequent cases of adaptation of agricultural pests to them. They began to develop resistance to the lethal action of pesticides, and this immunity is transmitted genetically to subsequent generations of pests. So, ants in the southern states of the United States developed immunity against dialdrin and heptachloran, while almost all beneficial insects died. Over the past decades, such immunity has already appeared in 200 species of insects harmful to agriculture, and the number of species of such arthropods is growing steadily.
Against pests of agriculture, which have developed immunity against pesticides, they began to create new chemical agents of a narrower and special spectrum of action. So, against rats and mice, which have become immune to a number of pesticides, in England, the drug "ratac" was created, containing chemical anticoagulants that disrupt natural blood coagulation, and rodents die from internal hemorrhage. However, it is not known how the human body will react if this new drug is ingested with food.
A very serious negative side of the use of pesticides is their ingestion through the food chains into human food. For example, in Hungary, winter wheat seed is treated with mercury-containing fungicides. Before the seeds germinated, they were pecked by migratory geese and, due to poisoning, several hundred per day perished. There was a danger of poisoning people due to shooting and eating the meat of such geese. A similar hazard has emerged in the western United States, where a potent pesticide used in wheat fields has been found at concentrations 20 times the safe level in the bones of hunting birds, and health officials have warned hunters about this.
Scientists of the Academy of Sciences of Tajikistan found that out of 17 herbicides, insecticides and fungicides used for cotton, 5 have mutagenic activity. Humanity still does not have systems for tracking the chemical composition and state of the biosphere sufficient in terms of coverage, density and information content. Unfortunately, the undesirable consequences of the uncontrolled use of pesticides affect not only those facilities where they are used. Their migration and accumulation can lead to disruption of the ecological balance of biocenoses and even to their destruction.
The total amount of pesticides used annually on the planet exceeds 1 million tons, which on average on the land surface is 0.07 kg / ha, and in some areas up to 4 kg / ha. It is gratifying that in recent years in a number of countries the most toxic types of pesticides have been banned and withdrawn from use. Scientists are working on the creation of pesticides with a narrow spectrum of action - for example, action on reproductive system a certain insect, as well as pesticides that are not resistant to natural agents.
Last years scientists are concentrating more and more efforts on finding new ways to combat agricultural pests - without the use of pesticides. In this regard, the promising direction is use of biological defense.
In a number of scientific institutions in the country and abroad, research is being carried out with insect entomophages, which are natural enemies of plant pests. For example, in the biological laboratory of the Russian plant protection station in Ramenskoye, near Moscow, an experimental technological line has been created to mechanize the processes of growing trichogramma - small insect that looks like a winged ant. One female trichogramma can destroy up to 30 eggs of pests - winter, cotton, cabbage, vegetable and other scoops, corn and meadow moths, apple and pea moths, etc. Work is also underway with the predatory fly gallium - an enemy of melon aphids, with the phytoseilus mite, keeping greenhouse cucumbers from pests, with lacewing.
Scientists of the Institute of Forestry and Timber of the Siberian Branch of the Russian Academy of Sciences used bacteria to prepare a new drug "infectious" against the Siberian silkworm, the reproduction of which was stopped in many regions of Siberia, as well as against pests of cotton and orchards of Central Asia and Moldova. Tests have shown that the drug is harmless to humans, animals, birds and beneficial insects... Siberian enterprises have launched the production of this drug.
The Institute of Biology of the Latvian Academy of Sciences found a way to use one of the types of microscopic fungi, the spores of which grow into agricultural pests (aphids and spider mites), destroying the living tissue of these insects. The spray preparation based on the fungus is safe for animals, birds and beneficial insects.
Zoologists in Singapore have bred, through targeted selection, tiny carp that feed almost exclusively on mosquito larvae in shallow bodies of water. The first generation of these fish with an enviable appetite has already led to a sharp decline in the test areas of mosquitoes - dangerous enemies of humans and animals in tropical countries.
The direct impact of man on the animal world is also human resettlement certain types animals to new habitats, and such relocations can affect not only the fauna itself, but in some cases have much broader consequences.
In 1868, the Frenchman Truvelot, in order to obtain new types of silk from the cocoons of the gypsy moth, discharged the gypsy moth eggs from Europe to the area of Medford, Massachusetts. The silkworm acclimatized well and began to multiply rapidly. Eating all the foliage in the trees, caterpillars in search of food crawled into houses and devoured the leaves. indoor plants, causing a lot of trouble for the inhabitants of apartments and houses: they climbed into bed, clothes, exuding an unbearable smell with their bodies and excrement. Domestic and wild animals starved and died from lack of food. People also began to starve due to difficulties with the delivery of food: the wheels of the trains crushed a thick layer of caterpillars on the rails, the locomotives skidded. People began to move from the area captured by caterpillars, burned forests infected with them, cleaned roads and dwellings with fire and caustic liquids. In less than 40 years, caterpillars have captured an area of 11 thousand miles 2. Only after the natural enemies of the silkworm were specially brought to America, its aggression was limited.
In the 19th century, a large (up to 25 cm long) Achatina snail was exported from Madagascar Island as a supposed remedy for tuberculosis. With human participation, she came to India, Sri Lanka, the Malay Archipelago, the Marquesas Islands and California. The gluttonous snail wreaked havoc on sugarcane, tea and rubber plantations. They collected it, burned it, tried to drown it in the sea, poisoned it with pesticides, annually destroy it by the millions, but the struggle continues to this day.
The story of the resettlement of rabbits to Australia is widely known. Pigs brought to many countries by man also ended up in New Zealand. There, released into the wild, they ran wild and, addicted to eggs, dramatically reduced the populations of a number of species. flightless birds, and the lizard, the hatteria, survived only on small islands on the coast, where pigs did not penetrate.
Opossum was brought there from America. This well-climbing animal liked to eat the tops of trees, which is why in its habitats, shortened twisted branching trunks appear in the trees, which are not suitable as a building material, which leads to large losses. In addition, possums are damaging to the energy sector: climbing on poles and swinging on wires, they cause wire breaks and short circuits.
Per row tropical islands the mongoose was introduced to fight rats and snakes. In Fiji, mongooses have dramatically reduced the number of birds nesting on the ground, especially from the herders and chickens, as well as the Fijian iguana. In Cuba, the mongooses have almost completely exterminated the endemic snake, and the number of species of non-venomous snakes has decreased.
A raccoon dog was brought to some parts of our country. She quickly took root and began to destroy the nests and eggs of grouse birds and, moreover, turned out to be a carrier of the rabies virus. I had to take measures to reduce the number of this animal.
Of course, there are also known cases of human importation of certain species of animals, which turned out to be successful, without serious consequences, for example, the importation of muskrat to Russia, to California and Georgia of some insects to combat citrus pests, etc. species of animals convince us of the need for a preliminary comprehensive study of the consequences that can occur as a result of such an experiment.
Migration of certain animals, which is not programmed by man, also happens, albeit with his participation. So, together with the nomads from Asia, the black cockroach came to Europe. Inadequate customs control created an opportunity for the Colorado potato beetle in the holds of ships to cross the ocean with potatoes and get from America to Europe, from where it gradually moves east.
In the 60s in the Moscow region, a small deer bloodsucker was discovered, which appeared in connection with unsuccessful attempt to acclimatize marals here: marals have not taken root, and the bloodsucker thrives on moose.
Smirnov's skin beetle arrived from Kenya with cargoes to Europe; now it is found in large numbers in apartments in Moscow, St. Petersburg, Sochi, Sverdlovsk and a number of regions of Western Europe.
In the 50s on Black Sea coast In the Caucasus, a Japanese leafhopper was discovered, introduced by chance with some plants from Japan and now becoming a serious pest of cultivated plants in the Caucasus.
* This work is not scientific work, is not a final qualifying work and is the result of processing, structuring and formatting the collected information intended for use as a source of material for self-preparation of educational works.
Despite the enormous value of the animal world, man, possessing fire and weapons, even in the early periods of his origins began to exterminate animals (the so-called "Pleistocene overhunting", and now, armed with modern technology, he has developed a "rapid attack" on the entire natural biota. The reasons for the loss of biological diversity, the decline in the number and extinction of animals are as follows:
- violation of the habitat;
- over-catching, fishing in prohibited areas;
- direct destruction for the purpose of product protection;
- accidental (unintentional) destruction;
- environmental pollution.
Violation of the habitat due to deforestation, plowing of steppes and fallow lands, drainage of bogs, regulation of runoff, creation of reservoirs and other anthropogenic influences radically changes the breeding conditions of wild animals, their migration paths, which has a very negative effect on their numbers and survival.
For example, in the 60-70s. At the cost of great efforts, the Kalmyk saiga population was restored. Its population exceeded 700 thousand. At present, the saiga in the Kalmyk steppes has become much smaller, and its reproductive potential has been lost. The reasons are various: intensive overgrazing livestock, excessive enthusiasm for wire fences, the development of a network of irrigation canals that cut the natural migration routes of animals, as a result of which thousands of saigas drowned in canals on their way.
Something similar happened in the area of Norilsk in 2001. The laying of the gas pipeline without taking into account the migration of deer in the tundra led to the fact that animals began to stray into huge herds in front of the pipe, and nothing could force them to turn off the century-old path. As a result, many thousands of animals died. In the Russian Federation, there is a decrease in the number of hunting species animals, which is primarily due to the current socio-economic situation and their increased illegal hunting (for example, poaching).
Excessive prey serves the main reason downsizing and large mammals(elephants, rhinos, etc.) in Africa and Asia. The high cost of ivory in the world market leads to the death of about 60 thousand elephants in these countries annually. However, small animals are being destroyed on an unimaginable scale. According to the calculations of world experts in the field of zoology and general ecology and Russian corresponding members of the Russian Academy of Sciences and doctors of biological sciences A.V. Yablokova and S.A. Ostroumova, in the poultry markets big cities In the European part of Russia, at least several hundred thousand small songbirds are sold annually. Volume international trade wild birds exceeds seven million.
Other reasons for the decline in the number and disappearance of animals are their direct destruction to protect agricultural products and commercial objects (the death of birds of prey, ground squirrels, pinnipeds, coyotes, etc.); accidental (unintentional) destruction (on highways, during military operations, when mowing grass, on power lines, when regulating water flow, etc.); environmental pollution (pesticides, oil and oil products, atmospheric pollutants, lead and other toxicants).
We will give only two examples related to the reduction of animal species due to unintentional human impact.As a result of the construction of hydraulic dams in the Volga riverbed, the spawning grounds of salmon fish (white fish) and anadromous herring have been completely eliminated, and the area of distribution of sturgeon fish has decreased to 400 hectares, which is 12% of the former spawning fund in the Volga-Akhtubinskaya floodplain in the Astrakhan region.
In the central regions of Russia, manual haymaking kills 12-15% of wild game, and mechanized hay harvesting - 30%. In general, the death of game in the fields during agricultural work is seventy times higher than the volume of hunting by hunters.
The indirect impact of man on the animal world consists in the pollution of the habitat of living organisms, its change or even destruction. Thus, water pollution is very harmful to the populations of amphibians and aquatic animals. For example, the population of the Black Sea dolphin population is not recovering, since as a result of entering the sea waters a huge amount of toxic substances, the mortality of individuals is high.
confirmed that this is the result of suppression immune system fish due to dumping into the Volga technical waste as well as runoff from rice paddies in the delta.
Often the reason for the decline in the number and disappearance of populations is the destruction of their habitat, the fragmentation of large populations into small ones, isolated from each other. This can happen as a result of deforestation, road construction, new businesses, agricultural land development. For example, the number Ussuri tiger decreased sharply as a result of human development of territories within the range of this animal and a reduction in its food supply.
