The negative impact of man on the number and. Human influence on the animal world

Despite the enormous value of the animal world, having mastered fire and weapons, man is still in early periods of its history, it began to exterminate animals, and now, armed with modern technology, it has developed a “rapid attack” on them and on the entire natural biota. Of course, on Earth and in the past, at any time, for a variety of reasons, there was a constant change of its inhabitants. However, now the rate of extinction of species has increased dramatically, and more and more new species are being drawn into the orbit of endangered species, which were quite viable before. Prominent Russian environmental scientists A. V. Yablokov and S. A. Ostroumov (1983) emphasize that in the last century the rate of spontaneous emergence of species is tens (if not hundreds) times lower than the rate of species extinction. We are witnessing the simplification of both individual ecosystems and the biosphere as a whole.

So far, there is no answer to the main question: what is the possible limit of this simplification, which must inevitably be followed by the destruction of the "life support systems" of the biosphere.

The main causes of biodiversity loss, population decline and extinction of animals are as follows:

¨ habitat disturbance;

¨ over-harvesting, fishing in prohibited areas;

¨ introduction (acclimatization) of alien species;

¨ direct destruction in order to protect products;

¨ accidental (unintentional) destruction;

¨ environmental pollution.

Habitat disturbance, due to deforestation, plowing of steppes and fallow lands, drainage of swamps, regulation of flow, creation of reservoirs and other anthropogenic impacts, radically changes the conditions for the reproduction of wild animals, their migration routes, which has a very negative impact on their numbers and survival.

For example, in the 60s and 70s the Kalmyk saiga population was restored at the cost of great efforts. Its number exceeded 700 thousand heads. Currently, the saiga in the Kalmyk steppes has become much smaller, and its reproductive potential has been lost. The reasons are various: intensive overgrazing of livestock, excessive use of wire fences, the development of a network of irrigation canals that cut off the natural migration routes of animals, as a result of which thousands of saigas drowned in the canals along their path.

Something similar happened in the region of Norilsk in the 1990s. The laying of the gas pipeline without taking into account the migration of deer in the tundra led to the fact that the animals began to huddle in front of the pipe into huge herds, and nothing could make them turn off the centuries-old path. As a result, many thousands of animals died.

One of the characteristic signs of habitat disturbance is the disintegration of the previously continuous area of ​​distribution of the species into separate islands. According to Yu. G. Markov (2001), predators of the highest trophic level, species of large animals, as well as species narrowly adapted to a particular habitat are most at risk of extinction.

Under excessive getting This refers to both direct persecution and violation of the population structure (hunting), as well as any other removal of animals and plants from the natural environment for various purposes.

AT Russian Federation there was a decrease in the number of hunting species animals, which is connected, first of all, with the current socio-economic situation in the country and their increased illegal production.

Excessive booty serves main reason downsizing large mammals(elephants, rhinos, etc.) in Africa and Asia. High price Ivory on the world market leads to the annual death of about 60 thousand elephants in these countries.

However, even small animals are being destroyed on an unimaginable scale. According to the calculations of A. V. Yablokov and S. A. Ostroumov, at least several hundred thousand small songbirds are sold annually in the bird markets of large cities in the European part of Russia. The international trade in wild birds exceeds seven million, most of which die either on the road or shortly after arrival.

The negative effects of such a factor of population decline as excessive hunting are also manifested in relation to other representatives of the animal world. For example, the stocks of the East Baltic cod are currently at such a low level, which has not been noted in the entire history of the study of this species in the Baltic. By 1993, the total catches of cod decreased by 16 times compared to 1984, despite the increasing fishing effort (Government report ..., 1995).

Stocks of sturgeon in the Caspian Sea have been so undermined that in one or two years it will be necessary to introduce a ban on their commercial fishing. The main reason for this is poaching, which everywhere has taken on a scale comparable to fishing. The ban on fishing for capelin in the Barents Sea is expected to continue, as there is no hope of restoring the population, which has been undermined by predatory consumption. Since 1994, the fishing of the Azov-Kuban herring in the Don has been prohibited, due to the low population size for the same reason.

The third most important reason for the decline and extinction of animal species is introduction (acclimatization) of alien species. There are numerous cases of extinction of native (indigenous) species or their oppression due to the influence of introduced species of animals or plants on them. Widely known examples in our country negative impact American mink to a local species ¾ European mink, Canadian beaver ¾ to European, muskrat to muskrat, etc.

Many scientists believe that it is only in depleted anthropogenic ecosystems that new species can be introduced to balance the ecological system.

So, for example, according to A. G. Bannikov, the introduction of herbivorous fish ¾ silver carp, grass carp ¾ into artificial channels is quite acceptable, where they will prevent their overgrowth.

In general, the experience of the production and acclimatization stations of Glavrybvod and some other organizations allows us to look more optimistically at the prospects for the acclimatization of fish and aquatic invertebrates, of course, with sufficient environmental justification.

According to the State report…, 1995, a number of acclimatization works of Russian scientists were highly appreciated at the world level. This, for example, is the transoceanic transplantation of the king crab into the Barents Sea, unprecedented in the history of acclimatization, where its self-reproducing population has now formed. The acclimatization of pilengas in the Sea of ​​Azov and pink salmon in the European North was also successful.

Other reasons for the decline and extinction of animals ¾ their direct destruction for protection agricultural products and commercial objects (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, air pollutants, lead and other toxicants).

Here are just two examples related to the reduction of animal species due to unintended human impact. As a result of construction hydraulic dams spawning grounds have been completely eliminated in the Volga riverbed salmon fish(whitefish) and anadromous herring, and the area sturgeon fish decreased to 400 ha, which is 12% of the former spawning stock in the Volga-Akhtuba floodplain.

In the central regions of Russia, 12-15% of field game die when haying by hand, ¾ 25-30% when using horse-drawn mowers, and ¾ 30-40% when hay is harvested mechanically. In the fields of Ukraine, up to 60-70% of the total number of rabbits die from agricultural machinery, and there are many broods of birds. In general, the death of game in the fields during agricultural work is seven to ten times higher than the volume of its prey by hunters.

Numerous observations indicate that in nature, as a rule, several factors act simultaneously, causing the death of individuals, populations and species as a whole. When interacting, they can lead to serious negative results, even with a small degree of severity of each of them.

test questions

1. What are the reasons for the sharp decline in biodiversity in nature at the present time?

2. Describe the functions of the forest in the biosphere.

3. Why is forest loss one of the most serious environmental problems?

4. What are the environmental consequences of anthropogenic impact on biotic communities?

5. What is the main ecological function of the animal world?

6. What are the main reasons for the extinction of animals, the reduction in their numbers and the loss of their biological diversity at the present time.

The extinction of some and the appearance of other animal species occurs at the entrance of evolution, with a change climatic conditions, landscapes, as a result of competitive relationships. Under natural conditions, this process is slow. According to the calculations of D. Fisher 11976), before the appearance of man on Earth, the average life expectancy of birds was about 2 million years, mammals - about 600 thousand years. Man hastened the death of many species. He noticeably influenced animals already in the Paleolithic, more than 250 thousand years ago, when he mastered fire. Its first victims were large animals. In Europe, as early as 100,000 years ago, man contributed to the extinction of the forest elephant, forest clump, giant deer, woolly rhinoceros, and mammoth. AT North America about 3 thousand years ago, apparently not without human influence, the mastodon, giant llama, black-toothed cat, and huge stork died out. The island fauna turned out to be the most vulnerable. Before the arrival of Europeans in New Zealand, the Maori, local residents, exterminated more than 20 species of huge moa birds. The early period of the destruction of animals by man was called by archaeologists "Pleistocene overfishing." Since 1600, the extinction of species has been documented. Since that time, according to the International Union for Conservation of Nature (IUCN), 94 species (1.09%) of birds and 63 species (1.48%) of mammals have become extinct on Earth. The death of more than 75% of mammal species and 86% of birds from the above number is associated with human activities.

Human economic activity greatly affects animals, causing an increase in the number of some, a decrease in the populations of others, and the extinction of others. Human impact on animals can be direct or indirect.

Direct impact (persecution, extermination and resettlement) is experienced mainly by game animals, which are hunted for fur, meat, fat, etc. As a result, their numbers are decreasing, and certain types disappear.

To combat pests of agricultural and forest plants, the relocation of animals from other areas is widely practiced. At the same time, it is not uncommon for settlers 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. In many countries and on the continents, with the active or passive participation of man, new species of animals were brought and acclimatized. They began to play an important role in the life of local nature and people. Especially many new species were brought to Australia, New Zealand and oceanic islands during the period of mass migration of Europeans to these then uninhabited 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, and 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 areas. the globe. For example, when inspecting aircraft at airports in the United States and Hawaiian Islands in 1952-1961 50 thousand species of insects were discovered. A special quarantine service has been introduced in commercial ports to prevent the accidental import of animals.

The direct impact of man on animals should include their death from chemical substances used to control agricultural pests and weeds. In this case, not only pests often die, but also animals useful to humans. Numerous facts of poisoning of fish and other animals with fertilizers and toxic substances should be attributed to the same cases. Wastewater discharged by industrial and household enterprises.

Indirect human impact on animals is associated with changes in habitat (during 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 being 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 the tundra and reached the coast Pacific Ocean. Following deforestation, the appearance of fields and meadows, the ranges of the lark, lapwing, starling, and rook moved to the north, to the taiga zone.

Under the influence economic activity new anthropogenic landscapes with specific fauna emerged. The urbanized territories occupied by cities and industrial agglomerations are the most changed. Some species of animals have found favorable conditions in anthropogenic landscapes. Even in taiga zone began to meet house and field sparrows, village and city swallows, jackdaws, rooks, house mice, gray rats, and some types of insects. The fauna of anthropogenic landscapes has a small number of species and high density animal population.

Most species of animals, not adapted to the conditions changed by man, move to new places or die. With the deterioration of living conditions under the influence of human economic activities, many types of natural landscapes reduce their numbers. Baibak ( marmota bobak), a typical inhabitant of the virgin steppes, in the past was widespread in the steppe regions of the European part of Russia. As the steppes were shattered, its numbers decreased, and now it has survived only in certain areas. Together with the marmot, the shelduck duck, which nested in the marmot's burrows, disappeared from the steppes, and now has lost its nesting sites. Cultivation of land also had a negative impact on other indigenous inhabitants of the virgin steppe - bustards and little bustards. In the past they were numerous in the steppes of Europe, Kazakhstan, Western Siberia, Transbaikalia and the Amur region, are now preserved in small numbers only in Kazakhstan and in the south of Western Siberia. Shallowing of rivers, drainage of swamps and floodplain lakes, reduction in the area of ​​sea estuaries suitable for nesting, molting and wintering waterfowl, caused a sharp decline in their species. The negative impact of humans on animals is on the rise. To date, approximately 150 species and subspecies of birds have disappeared in the world. According to the IUCN, one species (or subspecies) of vertebrates dies each year. The danger of extinction threatens more than 600 species of birds and about 120 species of mammals, many species of fish, amphibians, reptiles, mollusks, and insects.

The extinction of some and the emergence of other animal species is inevitable and natural. This happens during natural evolution, when climatic conditions change, landscapes as a result of competitive relationships. This process is slow. Before the appearance of man on Earth, the average life expectancy of a species in birds was about 2 million years, mammals - about 600 thousand years. Man hastened the death of many species.

Since 1600, when the extinction of species began to be documented, 94 species of birds and 63 species of mammals have become extinct on Earth (Fig. 2.). The death of most of them is associated with human activity (Fig. 1).

Rice. one. Reducing the number of whales

Rice. 2. Increase in the number of species of extinct birds every fifty years (from 1600 to 2000)

Man, through his actions, greatly influences animal world, causing an increase in the number of some species, a decrease in others and the death of others. This impact can be direct or indirect.

A direct impact (persecution, extermination, resettlement, breeding) is experienced by game animals, which are hunted for fur, meat, fat, etc. As a result, their numbers are declining, and some species are disappearing.

To control agricultural pests, a number of species are relocated from one area to another. At the same time, it is not uncommon for settlers to become pests themselves. For example, the mongoose, brought to the Antilles to control rodents, began to harm ground-nesting birds and spread rabies among animals.

The direct effects of humans on animals include their death from pesticides used in agriculture, and from poisoning emissions industrial enterprises.

Indirect influence of man on animals appears due to changes habitat when cutting down forests, plowing steppes, draining swamps, building dams, building cities, towns, roads, etc.

Some species in a human-modified environment find favorable conditions for themselves and expand ranges. Thus, house and field sparrows, following the advance of agriculture to the north and east in the Palearctic, reached the tundra and the Pacific coast. Following the appearance of fields and meadows, the lark, lapwing, starling, and rook moved far to the north.

Under the influence of economic activity arose anthropogenic landscapes with their characteristic fauna. Only in settlements in the subarctic and temperate zone northern hemisphere there are a house sparrow, a city swallow, a jackdaw, a house mouse, a gray rat, a crow, and some insects.

Most animal species cannot adapt to the changed conditions, are forced to move to new areas, reduce their numbers and die. So, as the European steppes were plowed up, the number of marmots-babaks was greatly reduced. Together with the marmot, the shelduck duck that nested in its burrows disappeared. Steppe birds - the bustard and the little bustard - have disappeared in many areas of their distribution.

Despite the enormous value of the animal world, man, wielding fire and weapons, began to exterminate animals even in the early periods of his history. ENVIRONMENTALISTS EMPHASIZE THAT IN THE LAST CENTURY THE RATES OF APPEARANCE OF SPECIES ARE DOZENS (IF NOT HUNDREDS) OF TIMES LOWER THAN THE RATES OF EXTINCTION OF SPECIES. THERE IS NO ANSWER TO THE MAIN QUESTION YET: WHAT IS THE POSSIBLE LIMIT OF THIS SIMPLIFICATION, WHICH SHOULD BE INEVITABLY FOLLOWED BY THE DESTRUCTION OF THE "LIFE SUPPORT SYSTEMS" OF THE BIOSPHERE.

THE MAIN CAUSES OF BIODIVERSITY LOSS, ANIMAL REDUCTION AND EXTINCTION ARE THE FOLLOWING: - HABITAT DISTURBATION; - EXCESSIVE EXTRACTION, FISHING IN PROHIBITED ZONES; - INTRODUCTION (ACCLIMATIZATION) OF ALIEN SPECIES; - DIRECT DESTRUCTION TO PROTECT PRODUCTS; - ACCIDENTAL (UNINTENDED) DESTRUCTION; - ENVIRONMENT POLLUTION. Numerous observations indicate that in nature, as a rule, several factors act simultaneously, causing the death of individuals, populations and species as a whole. When interacting, they can lead to serious negative consequences, even with a small degree of severity of each of them.

Other reasons for the decrease 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). UNDER MODERN CONDITIONS, UNDER THE INFLUENCE OF RAPIDLY DEVELOPING PRODUCTION FORCES AND POPULATION GROWTH, THE IMPACT OF HUMAN ECONOMIC ACTIVITIES ON THE NATURAL ENVIRONMENT HAS INCREASED, THAT MAKED THE PROBLEM OF NATURE PROTECTION, INCLUDING ANIMAL WORLD, PARTICULARLY ACTUAL.

In modern conditions, under the influence of rapidly developing productive forces and population growth, the impact of human economic activity on natural environment which made the problem of nature conservation, including wildlife, particularly relevant. CURRENTLY 143 RESERVES WITH A TOTAL AREA OF 13.7 MILLION HA ARE OPERATING IN OUR COUNTRY. THEY EXCLUDED ALL ECONOMIC ACTIVITIES (GRASS MOWING, FOREST CUTTING, CATTLE GRAZING, HUNTING) AND OTHER HUMAN INTERVENTIONS NOT RELATED TO NATURE PROTECTION PURPOSES. PROTECTED FORESTS, PERFORMING WATER PROTECTION, PROTECTIVE, SANITARY-HYGIENIC AND HEALTH FUNCTIONS, ARE IMPORTANT FOR THE PRESERVATION OF MANY ANIMALS AND PLANTS. Forms of nature protection in Russia are different. Great role in the protection of nature in our country state reserves designed to preserve especially valuable natural complexes.

* this work is not a 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-study educational work.

Despite the enormous value of the animal world, man, wielding fire and weapons, even in the early periods of his origins began to exterminate animals (the so-called "Pleistocene overfishing", and now, armed modern technology, developed a "rapid attack" on the entire natural biota. The main causes of biodiversity loss, population decline and extinction of animals are as follows:

— violation of the environment;

— excessive extraction, fishing in prohibited areas;

— direct destruction in order to protect products;

- accidental (unintentional) destruction;

— environmental pollution.

Habitat disturbance due to deforestation, plowing of steppes and fallow lands, drainage of marshes, regulation of flow, creation of reservoirs and other anthropogenic impacts radically change the conditions for the reproduction of wild animals, their migration routes, which has a very negative impact on their numbers and survival.

For example, in the 60-70s. the Kalmyk saiga population was restored at the cost of great efforts. Its number exceeded 700 thousand heads. Currently, the saiga in the Kalmyk steppes has become much smaller, and its reproductive potential has been lost. The reasons are various: intensive overgrazing of livestock, excessive use of wire fences, the development of a network of irrigation canals that cut off the natural migration routes of animals, as a result of which thousands of saigas drowned in the canals along their path.

Something similar happened in the region of Norilsk in 2001. The laying of a gas pipeline without taking into account the migration of deer in the tundra led to the fact that animals began to huddle in front of the pipe into huge herds, and nothing could make them turn off the centuries-old path. As a result, many thousands of animals died. In the Russian Federation, there is a decrease in the number of hunting species of animals, which is primarily due to the current socio-economic situation and their increased illegal production (for example, poaching).

Excessive production is the main reason for the decline in the number of large mammals (elephants, rhinos, etc.) in Africa and Asia. The high cost of ivory in the world market leads to the annual death of about 60 thousand elephants in these countries. However, even 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. Yablokov and S. A. Ostroumov, at least several hundred thousand small songbirds are sold annually in the bird markets of large cities in the European part of Russia . The volume of international trade in wild birds exceeds seven million copies.

Other reasons for the decrease 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).

Let us give only two examples related to the reduction of animal species due to unintentional human impact. As a result of the construction of hydrotechnical dams in the Volga River, spawning grounds for 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-Akhtuba floodplain in the Astrakhan region.

In the central regions of Russia, 12-15% of field game perish during manual haymaking, and 30% during mechanized hay harvesting. In general, the death of game in the fields during agricultural work is seventy times higher than the volume of its prey by hunters.

The indirect impact of man on the animal world is the pollution of the habitat of living organisms, its change or even destruction. Thus, the populations of amphibians and aquatic animals are greatly harmed by water pollution. For example, the number of the Black Sea dolphin population is not restored, since as a result of entry into sea ​​waters a huge amount of toxic substances, the mortality of individuals is high.

confirmed that this is the result of suppression of the immune system of fish due to the discharge of technical waste into the Volga, as well as runoff from rice fields in the delta.

Often the reason for the reduction in the number and disappearance of populations is the destruction of their habitat, the fragmentation of large populations into small, isolated from each other. This can happen as a result of deforestation, road construction, new enterprises, agricultural land development. For example, the number Ussuri tiger decreased sharply due to human development of territories within the range of this animal and the reduction of its food supply.