What are the main reasons for the decline in the number and extinction of animals. The main reasons for the decline in the number of animals The reasons for the decline in species of animals and plants

Violation of the habitat, due to deforestation and burning of forests, plowing of steppes and fallow lands, drainage of swamps, regulation of runoff, creation of reservoirs and other anthropogenic influences, radically changes the breeding conditions of wild animals, their migration routes, which has a very negative effect on their numbers and survival ... Habitat destruction is recognized as the main cause of species extinction or decline. It put more than 390 species of vertebrates in a threatening state, which, excluding pollution factors, is 50% among all other reasons for their extinction (Yablokov et al., 1985). [...]

One of the characteristic signs of habitat disturbance is the disintegration of the previously continuous distribution area 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 certain habitat are most at risk of extinction. [...]

Excessive harvesting means both direct pursuit and violation of the population structure (hunting), and any other removal of animals and plants from the natural environment for various purposes (food, economic, medical, etc.). [...]

The abundance of many species of commercial fish fell to a very low level: 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, cod catches decreased compared to 1984 in 16 once. Sturgeon stocks in the Caspian and Azov Seas have been undermined by poaching, comparable to fishing, so that it is necessary to impose a ban on their commercial fishing. Since 1994, due to the low number, the fishing in the Don of the Azov-Kuban herring has been prohibited. [...]

The third most important reason for the decline in the number and extinction of animal species is the introduction (acclimatization) of alien species. There are numerous cases of extinction of indigenous (indigenous) species or their oppression due to the influence of imported animal or plant species on them. The introduction of new species into existing ecosystems should be approached with extreme caution. In our country, there are examples of the negative impact of the American mink on the local species - the European mink, the Canadian beaver - on the European beaver, muskrat - on the desman, etc. [...]

Other reasons for the decline in the number and extinction of animal species: direct destruction to protect agricultural products and commercial facilities ( predator birds, gophers, pinnipeds, coyotes, etc.); accidental (unintentional) destruction (on roads, during hostilities, when mowing grass, on power lines, when regulating water flow, etc.); pollution of the environment with pesticides, oil and oil products, atmospheric pollutants, lead and other toxicants. [...]

Here are just two examples related to the decline in animal species due to unintentional human exposure. As a result of the construction of dams in the Volga channel, the spawning grounds for salmon and anadromous herring have been completely eliminated, and for sturgeons they have been reduced to 400 hectares, which is 12% of the previous spawning fund in the Volga-Akhtubinskaya floodplain. As a result of haymaking, from 12-15 to 30-40% of field game perishes, and in general, the death of game in the fields during agricultural work is seven to ten times higher than its prey by hunters. [...]

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

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

Violation of the habitat;

Over-catching, fishing in prohibited areas;

Introduction (acclimatization) of alien species;

Direct destruction for the purpose of product protection;

Accidental (unintentional) destruction;

Contamination of the environment.

Habitat disruption due to deforestation and burning of forests, plowing of steppes, drainage of swamps, regulation of runoff, construction of dams and creation of reservoirs and other anthropogenic influences, radically changes the breeding conditions of wild animals, their migration routes, which has a very negative effect on their numbers and survival. Habitat destruction is recognized as the main cause of species extinction or decline.

Deforestation in many countries has caused shallowing of rivers and lakes, which in turn has led to overgrowth. As a result, the supply of nutrients to these reservoirs has decreased, the oxygen regime, food and other living conditions of fish have worsened, and the reserves of the latter have decreased.

The shallowing of rivers, drainage of marshes and floodplain rivers, the disappearance of many shallow sea waters led to a very significant reduction in the territories suitable for nesting, molting and wintering of waterfowl, which, in turn (along with intensive hunting), caused a sharp decrease in the natural reserves of this valuable group birds.

Under over-mining I mean both direct pursuit and violation of the structure of the population (hunting), and any other removal of animals and plants from the natural environment for various purposes (food, economic, medical, etc.)

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 indigenous (indigenous) species due to their oppression or the influence of imported animal or plant species on them. Thus, the muskrat, a North American rodent imported into Russia in the 20s of the 20th century, has now populated almost the entire territory of the country, displacing the desman, which is listed in the Red Book of the Russian Federation, and the raccoon dog since its release in a number of places in the ETR is now became a common predator throughout this part of the country, destroying land-nesting birds and other animals. This list can be supplemented by the American mink, which has replaced the European mink.

Other reasons for the decline in the number and extinction of animal species:

- direct destruction for protection agricultural products and commercial objects (birds of prey, gophers, pinnipeds, coyotes, etc.);

- accidental (unintentional) destruction (on highways, during military operations, when mowing grass, on power lines, when regulating water flow, etc.);

- pollution pesticides, oil and oil products, atmospheric pollutants, other toxicants. So, in Sweden, the use of pesticides led to the death of primarily predatory birds (peregrine falcon, kestrel, white-tailed eagle, eagle owl, long-eared owl, etc.), larks, rooks, pheasants, partridges die. A similar picture is observed in many Western European countries.

The fauna of our planet has about 2 million species of animals. As a result of human impact, the number of many species has significantly decreased, and some of them have completely disappeared. Modern man exists on Earth for about 40 thousand years. He began to engage in animal husbandry and agriculture only 10 thousand years ago. Therefore, for 30 thousand years, hunting was almost the exclusive source of food and clothing. Improvement of tools and methods of hunting was accompanied by the death of a number of animal species. Weapon development and Vehicle allowed a person to penetrate into the most distant corners of the globe. And everywhere the development of new lands was accompanied by the merciless extermination of animals, the death of a number of species. The tarpan, the European steppe horse, was completely destroyed by hunting. Tours, spectacled cormorants, Labrador eiders, Bengal hoopoe and many other animals became victims of the hunt. As a result of unregulated hunting, dozens of species of animals and birds are on the verge of extinction. At the beginning of this century, the intensification of whaling (the creation of a harpoon cannon and floating bases for processing whales) led to the disappearance of individual whale populations, a sharp drop in their total number. The number of animals is decreasing not only as a result of direct extermination, but also due to the deterioration of environmental conditions in territories and ranges. Anthropogenic changes in landscapes adversely affect the living conditions of most animal species. Deforestation, plowing of steppes and prairies, drainage of swamps, regulation of runoff, pollution of the waters of rivers, lakes and seas, all this, taken together, interferes with the normal life of wild animals, leads to a decrease in their numbers even when hunting is prohibited. Intensive logging in many countries has changed forests. Coniferous forests are increasingly being replaced by small-leaved ones. At the same time, the composition of their fauna also changes. Not all animals and birds living in coniferous forests can find enough food and places for refuge in secondary birch and aspen forests. For example, squirrels and martens, many species of birds cannot live in them. The plowing of the steppes and prairies, the reduction of island forests in the forest-steppe are accompanied by the almost complete disappearance of many steppe animals and birds. Saigas, bustards, little bustards, gray partridges, quails, etc. have almost completely disappeared from steppe agrocenoses. The transformation and change in the nature of many rivers and lakes radically changes the living conditions of most river and lake fish, leads to a decrease in their numbers. Pollution of water bodies causes enormous damage to fish stocks. At the same time, the oxygen content in the water sharply decreases, which leads to massive fish killings. Dams on rivers have a huge impact on the ecological state of water bodies. They block the way for anadromous fish to spawn, worsen the condition of spawning grounds, and sharply reduce the inflow of nutrients into river deltas and coastal parts of seas and lakes. To prevent the negative impact of dams on the ecosystems of aquatic complexes, a number of engineering and biotechnical measures are being taken (fish passages and fish elevators are being built to ensure the movement of fish for spawning). The most effective way to reproduce a fish stock is to build fish hatcheries and fish hatcheries.

Which are distributed and live in various natural areas. Such biodiversity in different climatic conditions is not the same: some species adapt to the harsh conditions of the arctic and tundra, others learn to survive in deserts and semi-deserts, others love the warmth of tropical latitudes, the fourth inhabit forests, and the fifth spread over the wide expanses of the steppe. The state of the species, which in this moment exists on Earth, formed over 4 billion years. However, one is the decline in biodiversity. If it is not solved, then we will forever lose the world that we know now.

Reasons for the decline in biodiversity

There are many reasons for the decline in animal and plant species, and all of them directly or indirectly come from people:

• expansion of the territories of settlements;
• regular emissions of harmful elements into the atmosphere;
• transformation of natural landscapes into agricultural objects;
• usage chemical substances in agriculture;
• pollution of water bodies and soil;
• road construction and the position of communications;
• requiring more food and territories for life;
• experiments on crossing plant and animal species;
• destruction of ecosystems;
• caused by people.

Of course, the list of reasons goes on. Whatever people do, they affect the reduction of the areas of flora and fauna. Accordingly, the life of animals changes, and some individuals, unable to survive, die prematurely, and the number of populations is significantly reduced, often leading to the complete extinction of the species. Roughly the same thing happens with plants.

The value of biodiversity

Biological diversity different forms life - animals, plants and microorganisms is valuable in that it has genetic and economic, scientific and cultural, social and recreational, and most importantly - environmental significance. After all, the diversity of animals and plants makes up the natural world that surrounds us everywhere, so it must be protected. People have already caused irreparable damage that cannot be compensated for. For example, many species have been destroyed all over the planet:

Quagga

Sylphius

Solving the problem of biodiversity conservation

It takes a lot of effort to preserve biodiversity on earth. First of all, it is necessary that the governments of all countries give Special attention this problem and protected natural objects from the encroachments of different people. Also, work on the preservation of the world of flora and fauna is carried out by various international organizations in particular, Greenpeace and the UN.

Among the main measures that are being taken, it should be mentioned that zoologists and other specialists are fighting for each individual of an endangered species, creating reserves and nature parks where animals are under observation, creating conditions for them to live and increase populations. Plants are also artificially bred in order to increase their ranges, to prevent valuable species from perishing.
In addition, it is necessary to carry out measures to preserve forests, protect water bodies, soil and atmosphere from pollution, and apply them in production and everyday life. Most of all, the preservation of nature on the planet depends on ourselves, that is, on each person, because only we make a choice: to kill an animal or keep it alive, to cut down a tree or not, to pick a flower or plant a new one. If each of us protects nature, then the problem of biodiversity will be overcome.

"Methods for breeding animals and plants" - Methods for breeding plants and animals. Biology presentation on the topic: The further progress of mankind is largely associated with the development of biotechnology. Viruses are sometimes referred to as microorganisms. BIOTECHNOLOGY, the use of living organisms and biological processes in industrial production. Biotechnology.

"The Red Book of Plants and Animals" - Grown-up cranes begin to take care of themselves. The lotus is found in our Caspian and in Asia. The name "lady's slipper" came to us from time immemorial. Lady's slipper. There are several types of Venus shoes. Indeed, the flower of the lady's shoe is very similar to the graceful shoe of a beauty. Lotus.

"Poisonous plants and animals" - Poisoning with plant poisons occurs mainly in the warm season when eating unknown or inedible plants that are outwardly similar to edible species... Animals. Plant poisons are mainly related to alkaloids, glycosides, plant soaps, organic acids, resins.

"Animals and Plants of the Kuban" - Meetings with the Caucasian bear are quite common. Bears are also found in subalpine meadows. V last years there is a tendency towards a decrease in the number of animal species. Plants. There are crayfish and turtles. Fishes. Plantain, tansy, chamomile, and poppies are found in some places. Animals. The crevices in the mountains, niches under the rocks, and windbreaks serve as shelters for bears.

"Plants and Animals of the Arctic Deserts" - Forget-me-not. Buttercup. Reindeer moss. Saxifrage. Animals associated with the sea. Walrus. Seal. Bird market of Kaira. Purser. Eider. Polar poppy. Dwarf willow. Plants of arctic deserts. Arctic deserts about. Spitsbergen. Arctic deserts. The northern regions of the arctic deserts are covered with a variety of mosses and lichens.

“Ancient animals and plants” - There were no large animals at all; small centipedes, scorpions, arachnids and mites. In the first half of the Paleozoic, life existed only in the seas. Archeochiates. The crustaceans were widespread in the Silurian and Devonian. The Devonian forest was lifeless. At the end of the Devonian, the first amphibians, terrestrial tetrapods, appear.