Environmental factors of origin are divided into:

1. Biotic.

2. Abiotic.

3. Anthropogenic.

Changes in the environment that occurred as a result of human and other human activities are due to anthropogenic factors. Trying to remake nature in order to adapt it to his needs, a person transforms the natural environment of living organisms, exerting an influence on their life.

Anthropogenic factors include the following types:

1. Chemical.

2. Physical.

3. Biological.

4. Social.

Chemical anthropogenic factors include the use of mineral fertilizers and toxic chemicals for processing fields, as well as the pollution of all earth's shells by transport and industrial waste. The physical factors include the use of nuclear energy, an increase in the level of noise and vibration as a result of human activity, in particular when using various means of transportation. Biological factors are food. They also include organisms that can inhabit the human body or those for which the person is potentially food. Social factors are determined by the joint existence of people in society and their relationships.

The human impact on the environment can be direct, indirect and complex. The direct influence of anthropogenic factors is carried out with a strong short-term exposure to any of them. For example, when arranging a highway or laying railway tracks through a forest, seasonal fishing in a certain area, etc. Indirect impact is manifested by a change in natural landscapes during human economic activity of low intensity over a long period of time. At the same time, climate, the physical and chemical composition of water bodies are affected, the structure of soils, the structure of the Earth's surface, and the composition of fauna and flora change. This happens, for example, during the construction of a metallurgical plant near the railway without the use of the necessary treatment facilities, which entails environmental pollution by liquid and gaseous wastes. In the future, trees in the nearby territory die, animals are exposed to heavy metal poisoning, etc. The complex effect of direct and indirect factors entails the gradual appearance of pronounced changes in the environment, which may be due to rapid population growth, an increase in the number of livestock and animals living near human housing (rats, cockroaches, ravens, etc.), plowing of new lands, the ingress of harmful impurities into water bodies, etc. In such a situation, only those living organisms that are able to adapt to new conditions of existence can survive in a changed landscape.

In the 20th and 11th centuries, anthropogenic factors acquired great importance in changing climatic conditions, soil structure and composition of atmospheric air, salt and fresh water bodies, in reducing the area of \u200b\u200bforests, and extinction of many representatives of the plant and animal world.

All processes taking place in the biosphere are inextricably linked, and humanity is only a small fraction, or rather, just one species from organic life. Throughout its existence, man has sought and continues to strive not to adapt to the environment, but to use it with maximum benefit for himself. But now comes the realization that the deterioration of the biosphere is dangerous for us. According to statistics, up to 85% of human diseases are associated with negative environmental conditions.

Human influence on the environment

Let's start by explaining what anthropogenic factors are. This is a human activity that affects the environment.

Types of anthropogenic factors

1. Chemical - the use of pesticides, mineral fertilizers, as well as the pollution of the earth's shells by industrial and transport wastes. The same category includes alcohol, smoking, and medicines.

2. Physical factors of the environment - movement in airplanes, trains, atomic energy, noise and vibration.

4. Social anthropogenic factors are associated with society.

Major negative impact

In just the last few years, only in Russia the birth rate has decreased by 30%, and the mortality rate has increased by 15%. Half of the young people of military age are unsuitable for military service due to their state of health. Since the 70s of the last century, the frequency of cardiovascular and oncological diseases has increased by 50%. In many regions, the occurrence of allergies occurs in more than half of children. This is not a complete list of what anthropogenic factors lead to.

Consequences for the atmosphere

As you know, today around the world there are a huge number of industrial enterprises that round-the-clock dump pollutants into the atmosphere. As a result, sanitary violations in many areas exceed all permissible figures by tens of times. This leads to the fact that in cities the number of patients with bronchitis, allergies, asthma, ischemia is steadily increasing.

the greenhouse effect

If we talk about whether anthropogenic factors influence climate change, we can assure that in such a global sense, a person does not have such an effect. Forests are cut down, the atmosphere is polluted, cities are built up, and so on, but one active large volcano is able to fill the air with carbon dioxide in such a large volume that all of humanity has not produced in five years. We know that Eyyafyatlayokudl volcano awoke not so long ago, due to which flights in many countries were canceled. So in this sense, anthropogenic environmental factors play only a small role.

Flora and fauna

The situation with the fauna and flora is much worse. Although, as has been repeatedly proved, in the old days there was a completely different flora and fauna, but as a result of global disasters, everything changed dramatically and quickly. Of course, now man contributes to the destruction of many species, although there is no urgent need for food. Huge tracts of land are polluted by humans, so living conditions for animals become inappropriate.

Conclusion

In conclusion, we can say that to a greater extent anthropogenic activity is negative not so much for nature as for man himself. This means that we ourselves create negative conditions for ourselves, slowly destroying each other. Man-made disasters, an increase in the number of diseases, the emergence of new viruses, excess mortality rates and declining birth rates in developed countries are proof of this.

News and Society

Anthropogenic factors: examples. What is an anthropogenic factor?

  November 10, 2014

The scale of human activity over the past few hundred years has grown immeasurably, which means that new anthropogenic factors have also appeared. Examples of impact, the place and role of humanity in changing the environment - all of this later in the article.

What is a living environment?

Part of the Earth’s nature in which organisms live is their habitat. The resulting relationships, lifestyle, productivity, number of creatures are studied by ecology. The main components of nature are distinguished: soil, water and air. There are organisms that are adapted to live in one environment or in three, for example, coastal plants.

The individual elements interacting with living things and among themselves are environmental factors. Each of them is indispensable. But in recent decades, anthropogenic factors have acquired planetary significance. Although half a century ago, the influence of society on nature was not paid enough attention to, 150 years ago, the science of ecology itself was in its infancy.

What are environmental factors?

Environmental conditions can be very diverse: space, information, energy, chemical, climatic. Any natural components of a physical, chemical or biological origin are environmental factors. They directly or indirectly affect a single biological individual, population, and the entire biocenosis. There are no fewer phenomena associated with human activities, for example, the anxiety factor. Many anthropogenic factors influence the vital activity of organisms, the state of biocenoses and the geographical envelope. Examples:

• an increase in greenhouse gases in the atmosphere leads to climate change;
• monoculture in agriculture causes outbreaks of individual harmful organisms;
• fires lead to a change in the plant community;
• deforestation and the construction of hydropower plants changes the regime of rivers.

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What are the environmental factors?

The conditions affecting living organisms and their environment, according to their properties, can be attributed to one of three groups:

• inorganic or abiotic factors (solar radiation, air, temperature, water, wind, salinity);
• biotic conditions that are associated with the cohabitation of microorganisms, animals, plants, affecting each other, inanimate nature;
• anthropogenic environmental factors - the combined effect of the Earth's population on nature.

All of these groups are important. Every environmental factor is irreplaceable. For example, the abundance of water does not make up for the amount of mineral elements and light necessary for plant nutrition.

What is an anthropogenic factor?

The main environmental sciences are global ecology, human ecology and nature conservation. They are based on data from theoretical ecology; they widely use the concept of “anthropogenic factors”. Anthropos translated from Greek means "man", genos is translated as "origin". The word "factor" comes from the Latin factor ("doing, producing"). So called conditions affecting the processes, their driving force.

Any human impact on living organisms, the entire environment - these are anthropogenic factors. Examples exist, both positive and negative. There are cases of favorable changes in nature in connection with environmental protection. But more often society negatively, sometimes destructively affects the biosphere.

The place and role of the anthropogenic factor in changing the face of the Earth

Any type of economic activity of the population affects the relationship between living organisms and the natural environment, often leads to their disruption. On the site of natural complexes and landscapes there are anthropogenic:

• fields, gardens and kitchen gardens;
• reservoirs, ponds, canals;
• parks, forest belts;
• cultural pastures.

The similarities of natural complexes created by man are further influenced by anthropogenic, biotic and abiotic environmental factors. Examples: desert formation - on agricultural plantations; overgrowing of ponds.

How does man influence nature?

Humanity - part of the biosphere of the Earth - for a long period completely depended on the surrounding natural conditions. With the development of the nervous system, in particular the brain, thanks to the improvement of tools, man himself has become a factor in evolutionary and other processes on Earth. First of all, one must mention the mastery of mechanical, electrical, and atomic energy. As a result, the upper part of the earth's crust has changed significantly, the biogenic migration of atoms has increased.

The whole diversity of the environmental impact of society is anthropogenic factors. Examples of adverse effects:

• reduction of mineral reserves;
• deforestation;
• soil pollution;
• hunting and fishing;
• extermination of wild species.

The positive impact of man on the biosphere is associated with environmental measures. Reforestation and afforestation, landscaping and landscaping of settlements, the acclimatization of animals (mammals, birds, fish).

What is being done to improve the relationship between man and the biosphere?

The above examples of anthropogenic environmental factors, human intervention in nature indicate that the impact can be positive and negative. These characteristics are conditional in nature, because a positive influence under changing conditions often becomes its opposite, that is, it acquires a negative connotation. Population activities are more harmful to nature than good. This fact is explained by a violation of natural laws that have been in force for millions of years.

As far back as 1971, the United Nations Educational, Scientific and Cultural Organization (UNESCO) approved the International Biological Program called “Man and the Biosphere”. Its main task was to study and prevent adverse environmental changes. In recent years, adult and children's environmental organizations, scientific institutions are very concerned about the conservation of biological diversity.

How to improve environmental health?

We found out what the anthropogenic factor is in ecology, biology, geography and other sciences. It should be noted that the well-being of human society, the life of present and future generations of people depend on the quality and degree of influence of economic activity on the environment. It is necessary to reduce the environmental risk associated with the ever-increasing negative role of anthropogenic factors.

According to the researchers, even the conservation of biological diversity is not enough to ensure a healthy environment. It can be unfavorable for human life with its former biodiversity, but with strong radiation, chemical and other types of pollution.

An obvious connection between the health of nature, man and the degree of influence of anthropogenic factors. To reduce their negative impact, it is necessary to form a new attitude to the environment, responsibility for the safe existence of wildlife and the conservation of biodiversity.

Anthropogenic factors

environment, changes introduced into nature by human activity, affecting the organic world (see Ecology). Altering nature and adapting it to one’s needs, a person changes the environment of animals and plants, thereby affecting their life. Impact can be indirect and direct. Indirect impact is carried out by changing landscapes - climate, physical condition and chemistry of the atmosphere and reservoirs, the structure of the earth's surface, soil, vegetation and animal population. Of great importance is the increase in radioactivity as a result of the development of the nuclear industry and especially the testing of atomic weapons. A person consciously and unconsciously exterminates or supplants some types of plants and animals, spreads others or creates favorable conditions for them. For cultivated plants and domestic animals, man has created a largely new environment, repeatedly increasing the productivity of the developed lands. But this ruled out the possibility of the existence of many wild species. The increase in the population of the Earth and the development of science and technology have made it very difficult to find areas that are not affected by human activities in modern conditions (virgin forests, meadows, steppes, etc.). Improper plowing of land and excessive cattle grazing not only led to the death of natural communities, but also increased water and wind erosion of soils and shallowing of rivers. At the same time, the emergence of villages and cities created favorable conditions for the existence of many species of animals and plants (see Synanthropic organisms). The development of industry did not necessarily lead to the impoverishment of wildlife, but often contributed to the emergence of new forms of animals and plants. The development of transport and other means of communication contributed to the spread of both beneficial and many harmful species of plants and animals (see Anthropochoria). Direct exposure is directed directly to living organisms. For example, unsustainable fishing and hunting have sharply reduced the number of species. The growing force and the accelerating rate of change in nature by man make it necessary to protect it (see. Nature Conservation). The purposeful, conscious transformation of nature by man with penetration into the microworld and space marks, according to V. I. Vernadsky (1944), the formation of the “noosphere” - the shell of the Earth, altered by man.

Lit .:  Vernadsky V.I., Biosphere, t. 1-2, L., 1926; him, Biogeochemical essays (1922-1932), M.-L., 1940; Naumov N.P., Ecology of animals, 2nd ed., M., 1963; Dubinin N.P., Evolution of populations and radiation, M., 1966; Blagosklonov K.N., Inozemtsov A.A., Tikhomirov V.N., Nature protection, M., 1967.

Great Soviet Encyclopedia. - M .: Soviet Encyclopedia. 1969-1978 .

See what "Anthropogenic factors" are in other dictionaries:

Factors due to their origin of human activity. Environmental Encyclopedic Dictionary. Chisinau: Main Edition of the Moldavian Soviet Encyclopedia. I.I. Grandpa. 1989. Anthropogenic factors, factors due to their origin ... ... Ecological Dictionary

The totality of environmental factors due to accidental or deliberate human activity over the period of its existence. Types of anthropogenic factors Physical use of atomic energy, moving in trains and planes, ... ... Wikipedia

Anthropogenic factors  - * anthropogenic factors * anthropogenic factors the driving forces of processes occurring in nature, which in their origin are associated with human activity and the impact on the environment. The summarized action of A. f. embodied in ... ... Genetics. encyclopedic Dictionary

Forms of human society that lead to a change in nature as a living environment of man himself and other species of living things or directly affect their lives. (Source: “Microbiology: Glossary of Terms”, N. Firsov ... Dictionary of Microbiology

The result of human exposure to the environment in the process of economic and other activities. Anthropogenic factors can be divided into 3 groups: having a direct impact on the environment as a result of a sudden onset, ... ... Biological Encyclopedic Dictionary

ANTHROPOGENIC FACTORS  - factors due to human activities ... Dictionary of Botanical Terms

ANTHROPOGENIC FACTORS - environment, factors caused by households. human activities and affecting the business environment. Their impact can be direct, for example. deterioration of the structure and depletion of soils due to repeated treatment, or indirect, for example. relief changes, ... ... Agricultural Encyclopedic Dictionary

Anthropogenic factors  - (gr. - factors arising from the fault of a person) - these are the causes and conditions created (or arising) as a result of human activities that have a negative impact on the environment and human health. So, the products of some industrial ... ... Fundamentals of spiritual culture (encyclopedic dictionary of a teacher)

anthropogenic factors  - environment, factors caused by human economic activity and affecting the natural environment. Their impact can be direct, for example, deterioration of the structure and depletion of soils due to repeated treatment, or indirect, for example, ... ... Agriculture. Great Encyclopedic Dictionary

Anthropogenic factors  - a group of factors due to the influence of man and his economic activity on plants, animals and other natural components ...   Theoretical aspects and foundations of an environmental problem: an interpreter of words and ideomatic expressions

Books

• Forest soils of European Russia. Biotic and anthropogenic factors of formation, M. V. Bobrovsky. The monograph presents the results of an analysis of extensive factual material on the structure of soils in the forest territories of European Russia from the forest-steppe to the northern taiga. Features reviewed ...

Anthropogenic factors -  the totality of various human influences on inanimate and living nature. Only by their physical existence do people have a noticeable impact on the environment: in the process of breathing, they annually emit 1 · 10 12 kg of CO 2 into the atmosphere, and consume over 5-10 15 kcal with food.

As a result of human exposure, climate, surface topography, chemical composition of the atmosphere change, species and natural ecosystems disappear, etc. The most important anthropogenic factor for nature is urbanization.

Anthropogenic activity significantly affects climatic factors, changing their regimes. For example, mass emissions of solid and liquid particles from industrial enterprises can dramatically change the mode of dispersion of solar radiation in the atmosphere and reduce the arrival of heat to the Earth's surface. The destruction of forests and other vegetation, the creation of large artificial reservoirs in the former land areas increase energy reflection, and dust pollution, for example, snow and ice, on the contrary, increases absorption, which leads to their intense melting.

To a much greater extent, the biosphere is affected by the production activities of people. As a result of this activity, the relief, the composition of the earth's crust and atmosphere, climate change, fresh water is redistributed, natural ecosystems disappear and artificial agro-and technoecosystems are created, cultivated plants are cultivated, animals are domesticated, etc.

Human exposure can be direct and indirect. For example, deforestation and uprooting of the forest have not only a direct effect, but also an indirect one - the conditions for the existence of birds and animals change. It is estimated that since 1600, 162 species of birds, over 100 species of mammals and many other species of plants and animals have been destroyed by humans. But, on the other hand, it creates new varieties of plants and animal breeds, increases their productivity and productivity. Artificial resettlement of plants and animals also affects the life of ecosystems. So, rabbits brought to Australia multiplied so much that they caused huge damage to agriculture.

The most obvious manifestation of anthropogenic impact on the biosphere is environmental pollution. The value of anthropogenic factors is constantly growing, as a person more and more subordinates nature.

Human activity is the totality of a person’s transformation of natural environmental factors and the creation of new ones that did not exist in nature before. The smelting of metals from ores and the production of equipment are impossible without the creation of high temperatures, pressures, powerful electromagnetic fields. Obtaining and maintaining high crop yields requires the production of fertilizers and chemical plant protection products against pests and pathogens. It is impossible to imagine modern healthcare without chemo and physiotherapy.

Achievements of scientific and technological progress began to be used for political and economic purposes, which was extremely manifested in the creation of special environmental factors that hit a person and his property: from firearms to means of mass physical, chemical and biological effects. In this case, they talk about a combination of anthropotropic (aimed at the human body) and anthropocidal factors that cause environmental pollution.

On the other hand, in addition to such purposeful factors, in the process of exploitation and processing of natural resources, side chemical compounds and zones of high levels of physical factors will inevitably form. In the conditions of accidents and disasters, these processes can be spasmodic in nature with severe environmental and material consequences. Hence, it was required to create methods and means of protecting a person from dangerous and harmful factors, which was currently implemented in the system mentioned above - life safety.

Ecological plasticity.  Despite the wide variety of environmental factors, a number of general patterns can be identified in the nature of their effects and in the responses of living organisms.

The effect of the influence of factors depends not only on the nature of their action (quality), but also on the quantitative value perceived by organisms - high or low temperature, degree of illumination, humidity, amount of food, etc. In the process of evolution, the ability of organisms to adapt to environmental factors within certain quantitative limits has developed. A decrease or increase in the value of the factor beyond these limits inhibits vital activity, and when a certain minimum or maximum level is reached, the death of organisms occurs.

The zones of action of the environmental factor and the theoretical dependence of the vital activity of the organism, population, or community depend on the quantitative value of the factor. The quantitative range of any environmental factor, the most favorable for life, is called the environmental optimum (lat. ortimus -  the best). The values \u200b\u200bof the factor lying in the zone of oppression are called the ecological pessimum (the worst).

The minimum and maximum values \u200b\u200bof the factor at which death occurs are called, respectively environmental minimum  and environmental high

Any species of organisms, populations or communities are adapted, for example, to exist in a certain temperature range.

The ability of organisms to adapt to the existence of a particular range of environmental factors is called environmental plasticity.

The wider the range of environmental factors within which a given organism can live, the greater its environmental plasticity.

According to the degree of plasticity, two types of organisms are distinguished: stenobiont (stenoeki) and eurybiont (euryeki).

Stenobiont and eurybiont organisms differ in the range of environmental factors in which they can live.

Stenobiontic(column stenos  - narrow, narrow), or narrowly adapted, species can exist only with small deviations

factor from the optimal value.

Eurybiontic  (column eиrys -  wide) are called broadly adapted organisms that can withstand a large amplitude of environmental factors.

Historically, adapting to environmental factors, animals, plants, microorganisms are distributed in different environments, forming the whole variety of ecosystems that form the Earth's biosphere.

Limiting factors.  The idea of \u200b\u200blimiting factors is based on two environmental laws: the law of minimum and the law of tolerance.

The law of the minimum.  In the middle of the last century, the German chemist J. Liebig (1840), studying the effect of nutrients on plant growth, found that the crop does not depend on those nutrients that are required in large quantities and are abundant (for example, СО 2 and H 2 0 ), but from those that, although the plant needs it in smaller quantities, but which are practically absent in the soil or inaccessible (for example, phosphorus, zinc, boron).

This law was formulated by Liebig as follows: "The growth of a plant depends on the nutrient that is present in a minimal amount." This conclusion later became known as liebig's law of minimum  and has been extended to many other environmental factors. To limit, or limit, the development of organisms can be heat, light, water, oxygen, and other factors, if their value corresponds to the ecological minimum. For example, tropical angelfish dies if the water temperature drops below 16 ° C. And the development of algae in deep-sea ecosystems is limited by the depth of sunlight penetration: there are no algae in the bottom layers.

The Liebig minimum law in general terms can be formulated as follows: the growth and development of organisms depends, first of all, on those environmental factors whose values \u200b\u200bapproach the ecological minimum.

Studies have shown that the law of minimum has two limitations that should be considered in practical application.

The first limitation is that the Liebig law is strictly applicable only in the stationary state of the system. For example, in a certain pond, algae growth is limited in vivo by a lack of phosphates. Nitrogen compounds are also found in excess in water. If sewage with a high content of mineral phosphorus begins to be discharged into this reservoir, then the reservoir may “bloom”. This process will progress until one of the elements is consumed to a restrictive minimum. Now it can be nitrogen if phosphorus continues to flow. At the transitional moment (when nitrogen is still enough, and phosphorus is already enough), the effect of a minimum is not observed, i.e., none of these elements affects the growth of algae.

The second limitation is due to the interaction of several factors. Sometimes the body is able to replace the deficient element with another, chemically close. So, in places where there is a lot of strontium, in shells of mollusks it can replace calcium with a lack of the latter. Or, for example, the need for zinc in some plants is reduced if they grow in the shade. Consequently, a low concentration of zinc will less restrict the growth of plants in the shade than in bright light. In these cases, the limiting effect of even an insufficient amount of one or another element may not occur.

Law of tolerance  (lat . tolerantia  - patience) was discovered by the English biologist W. Shelford (1913), who drew attention to the fact that not only environmental factors whose values \u200b\u200bare minimal, but also those that are characterized by an environmental maximum can limit the development of living organisms. Excess heat, light, water, and even nutrients can be just as fatal as their lack. The range of environmental factors between the minimum and maximum W. Shelford called limit of tolerance.

The tolerance limit describes the amplitude of the fluctuations of factors, which ensures the most complete existence of the population. Individual individuals may have slightly different ranges of tolerance.

Later, tolerance limits were set for various environmental factors for many plants and animals. The laws of J. Liebig and W. Shelford helped to understand many phenomena and the distribution of organisms in nature. Organisms cannot be spread everywhere because populations have a certain tolerance limit with respect to fluctuations in environmental environmental factors.

W. Shelford's Law of Tolerance is formulated as follows: the growth and development of organisms depends primarily on those environmental factors whose values \u200b\u200bapproach an ecological minimum or ecological maximum.

The following was established:

Organisms with a wide range of tolerance to all factors are widespread in nature and are often cosmopolitan, for example, many pathogenic bacteria;

Organisms can have a wide range of tolerance for one factor and a narrow range for another. For example, people are more resilient to lack of food than to lack of water, that is, the tolerance limit for water is narrower than for food;

If the conditions for one of the environmental factors become suboptimal, then the tolerance limit for other factors may also change. For example, with a lack of nitrogen in the soil, cereals require much more water;

The real limits of tolerance observed in nature are less than the potential abilities of the organism to adapt to this factor. This is explained by the fact that, in nature, the limits of tolerance with respect to physical environmental conditions can be narrowed by biotic relationships: competition, lack of pollinators, predators, etc. Any person better realizes their potential opportunities in favorable conditions (training athletes for special training before important competitions, for example ) The potential ecological plasticity of the body, determined in laboratory conditions, is more than realized opportunities in natural conditions. Accordingly, they distinguish between potential and realized ecological niches;

The tolerance limits in breeding individuals and offspring are less than in adults, i.e., females during the breeding season and their offspring are less enduring than adult organisms. Thus, the geographical distribution of game birds is more often determined by the influence of climate on eggs and chicks, and not on adult birds. Care for posterity and respect for motherhood are dictated by the laws of nature. Unfortunately, sometimes social “achievements” contradict these laws;

Extreme (stressful) values \u200b\u200bof one of the factors lead to a decrease in the tolerance limit for other factors. If heated water is discharged into the river, then fish and other organisms spend almost all of their energy to overcome stress. They do not have enough energy to obtain food, protection from predators, reproduction, which leads to a gradual extinction. Psychological stress can also cause many somatic (column soma -  body) diseases not only in humans, but also in some animals (for example, dogs). Under stressful values \u200b\u200bof the factor, adaptation to it becomes more and more “expensive”.

Many organisms are capable of changing tolerance to individual factors if conditions change gradually. You can, for example, get used to the high temperature of the water in the bath, if you climb into warm water, and then gradually add hot. Such adaptation to a slow change in factor is a useful protective property. But it can be dangerous. Unexpected, without warning signals, even a small change can be critical. There is a threshold effect: the "last straw" can be fatal. For example, a thin twig can lead to a fracture of the already overloaded camel's back.

If the value of at least one of the environmental factors approaches a minimum or a maximum, the existence and prosperity of an organism, population, or community becomes dependent on precisely this limiting vital activity factor.

A limiting factor is any environmental factor approaching or exceeding the extreme values \u200b\u200bof tolerance limits. Such factors that deviate significantly from the optimum are of paramount importance in the life of organisms and biological systems. It is they who control the conditions of existence.

The value of the concept of limiting factors is that it allows you to understand the complex relationships in ecosystems.

Fortunately, not all possible environmental factors regulate the relationship between the environment, organisms, and humans. Priority in a given period of time are various limiting factors. The ecologist should also focus on these factors when studying ecosystems and managing them. For example, the oxygen content in terrestrial habitats is large and so accessible that it almost never serves as a limiting factor (with the exception of high altitudes and anthropogenic systems). Oxygen is of little interest to ecologists involved in terrestrial ecosystems. And in water, it is often a factor limiting the development of living organisms ("kills" of fish, for example). Therefore, a hydrobiologist always measures the oxygen content in water, unlike a veterinarian or an ornithologist, although oxygen is no less important for terrestrial organisms than for aquatic ones.

Limiting factors determine the geographical area of \u200b\u200bthe species. So, the advance of organisms to the south is limited, as a rule, by a lack of heat. Biotic factors also often limit the spread of certain organisms. For example, figs brought from the Mediterranean to California did not bear fruit there until they figured out to bring in a certain type of wasp - the only pollinator of this plant. Identification of limiting factors is very important for many types of activities, especially agriculture. With a targeted effect on limiting conditions, it is possible to quickly and efficiently increase plant productivity and animal productivity. So, when wheat is cultivated on acidic soils, no agronomic measures will be effective unless liming is used, which reduces the limiting effect of acids. Or if corn is grown on soils with a very low phosphorus content, then even with enough water, nitrogen, potassium and other nutrients, it stops growing. Phosphorus in this case is a limiting factor. And only phosphate fertilizers can save the crop. Plants can die from too much water or excess fertilizer, which in this case are also limiting factors.

Knowing the limiting factors provides the key to ecosystem management. However, in different periods of the life of the body and in different situations, various factors act as limiting. Therefore, only skilful regulation of living conditions can give effective management results.

Interaction and compensation of factors. In nature, environmental factors do not act independently of each other - they interact. An analysis of the influence of one factor on an organism or community is not an end in itself, but a way of assessing the comparative significance of various conditions acting together in real ecosystems.

Joint influence of factors  can be considered as an example of the dependence of mortality of crab larvae on temperature, salinity and the presence of cadmium. In the absence of cadmium, an environmental optimum (minimum mortality) is observed in the temperature range from 20 to 28 ° C and salinity from 24 to 34%. If cadmium, which is toxic to crustaceans, is added to the water, the ecological optimum shifts: the temperature lies in the range from 13 to 26 ° C, and salinity - from 25 to 29%. The limits of tolerance are also changing. The difference between the ecological maximum and the minimum for salinity after cadmium addition decreases from 11 - 47% to 14 - 40%. The tolerance limit for the temperature factor, on the contrary, is expanding from 9 - 38 ° С to 0 - 42 ° С.

Temperature and humidity are the most important climatic factors in terrestrial habitats. The interaction of these two factors, in essence, forms two main types of climate: marine and continental.

Ponds soften the land climate, since water has a high specific heat of fusion and heat capacity. Therefore, the marine climate is characterized by less sharp fluctuations in temperature and humidity than the continental.

The effect of temperature and humidity on organisms also depends on the ratio of their absolute values. Thus, temperature has a more pronounced limiting effect if the humidity is very high or very low. Everyone knows that high and low temperatures are less tolerated at high humidity than at moderate

The relationship between temperature and humidity as the main climatic factors is often depicted in the form of graphs of climograms that allow you to visually compare different years and areas and predict the production of plants or animals for certain climatic conditions.

Organisms are not slaves of the environment. They adapt to the conditions of existence and change them, that is, compensate for the negative impact of environmental factors.

Compensation of environmental factors is the desire of organisms to weaken the limiting effect of physical, biotic and anthropogenic influences. Compensation of factors is possible at the level of the organism and species, but is most effective at the community level.

At different temperatures, the same species, which has a wide geographical distribution, can acquire physiological and morphological (column to rphe -  shape, shape) features adapted to local conditions. For example, in animals, ears, tails, legs are shorter, and the body is more massive, the colder the climate.

This pattern is called the Allen rule (1877), according to which the protruding parts of the body of warm-blooded animals increase as they move from north to south, which is associated with adaptation to maintaining a constant body temperature in various climatic conditions. So, foxes living in the Sahara have long limbs and huge ears; the European fox is more squat, her ears are much shorter; and in the Arctic fox - the arctic fox - has very small ears and a short muzzle.

In animals with well-developed motor activity, factor compensation is possible due to adaptive behavior. So, lizards are not afraid of sudden cooling, because during the day they go out into the sun, and at night they hide under heated stones. Changes that occur in the process of adaptation are often genetically fixed. At the community level, factors can be compensated by changing species according to the gradient of environmental conditions; for example, with seasonal changes, a regular change in plant species occurs.

Organisms also use the natural periodicity of changes in environmental factors to distribute functions over time. They “program” life cycles in such a way as to maximize the use of favorable conditions.

The most striking example is the behavior of organisms depending on the length of the day - photoperiod.  The amplitude of the length of the day increases with geographical latitude, which allows organisms to take into account not only the time of year, but also the latitude of the area. A photoperiod is a “time relay” or trigger mechanism for a sequence of physiological processes. It determines the flowering of plants, molting, migration and reproduction in birds and mammals, etc. The photoperiod is associated with a biological clock and serves as a universal mechanism for regulating functions over time. A biological clock associates the rhythms of environmental factors with physiological rhythms, allowing organisms to adapt to diurnal, seasonal, tidal and other dynamics of factors.

Changing the photoperiod, you can cause changes in body functions. So, flower growers, changing the light regime in greenhouses, get off-season flowering of plants. If you immediately increase the length of the day after December, this can cause phenomena occurring in the spring: flowering plants, molting in animals, etc. For many higher organisms, adaptation to the photoperiod is fixed genetically, i.e., the biological clock can work even in the absence of a natural daily or seasonal dynamics.

Thus, the purpose of the analysis of environmental conditions is not to make an immense list of environmental factors, but to discover functionally important limiting factors  and assess the extent to which the composition, structure, and functions of ecosystems depend on the interaction of these factors.

Only in this case is it possible to reliably predict the results of changes and disturbances and manage ecosystems.

Anthropogenic limiting factors.  It is convenient to consider fires and anthropogenic stress as examples of anthropogenic limiting factors that allow managing natural and man-made ecosystems.

Fires  as an anthropogenic factor, they are often evaluated only negatively. Research over the past 50 years has shown that natural fires can be part of the climate in many terrestrial habitats. They affect the evolution of flora and fauna. Biotic communities have “learned” to compensate for this factor and adapt to it as to temperature or humidity. Fire can be considered and studied as an environmental factor, along with temperature, precipitation and soil. When used properly, fire can be a valuable environmental tool. Some tribes burned forests for their needs long before people began to systematically and purposefully change the environment. Fire is a very important factor, including because a person can control it to a greater extent than other limiting factors. It is difficult to find a piece of land, especially in areas with dry periods, where there would not be a fire at least once in 50 years. The most common cause of fires in nature is a lightning strike.

Fires are of various types and lead to different consequences.

Mounted, or “wild”, fires are usually very intense and not amenable to containment. They destroy the crown of trees and destroy all the organic matter of the soil. Fires of this type have a limiting effect on almost all organisms in the community. It should be many years before the site is restored again.

Ground fires are completely different. They have a selective effect: for some organisms are more limiting than for others. Thus, ground fires contribute to the development of organisms with high tolerance to their consequences. They can be natural or specially organized by a person. For example, planned forest burning is undertaken to eliminate competition for valuable species of bog pine from deciduous trees. Swamp pine, unlike hardwood, is resistant to fire, since the apical bud of its seedlings is protected by a bunch of long, poorly burning needles. In the absence of fires, the growth of deciduous trees drowns out the pine, as well as cereals and legumes. This leads to inhibition of partridges and small herbivores. Therefore, virgin pine forests with abundant game are ecosystems of the "fire" type, that is, in need of periodic ground fires. In this case, the fire does not lead to the loss of nutrients in the soil, does not harm ants, insects and small mammals.

A nitrogen-fixing bean is a little fire even useful. The burning is carried out in the evening, so that at night the fire was extinguished by dew, and the narrow front of the fire could be easily crossed. In addition, small ground fires complement the effect of bacteria on the conversion of dead residues into mineral nutrients suitable for a new generation of plants. For the same purpose, fallen leaves are often burned in spring and autumn. Scheduled burning is an example of managing a natural ecosystem using a limiting environmental factor.

The decision on whether to completely eliminate the possibility of fires or whether fire should be used as a control factor should entirely depend on what type of community is desired in this area. The American ecologist G. Stoddard (1936) was one of the first to “defend” controlled planned burns to increase the production of valuable wood and game even at a time when, from the point of view of foresters, any fire was considered harmful.

The close association of burnout with grass composition plays a key role in maintaining the amazing diversity of antelopes and predators eating them in the East African savannahs. Fires have a positive effect on many cereals, since their growth points and energy reserves are underground. After the burning of the dry aerial parts, the batteries quickly return to the soil and the grass grows magnificent.

The question “burn or not burn”, of course, can be confusing. By negligence, a person is often the cause of an increase in the frequency of fatal “wild” fires. The fight for fire safety in forests and recreation areas is the second side of the problem.

A private person in no case has the right to intentionally or accidentally cause a fire in nature - this is the privilege of specially trained people who are familiar with the rules of land use.

Anthropogenic stress  can also be considered as a kind of limiting factor. Ecosystems are largely able to compensate for anthropogenic stress. It is possible that they are naturally adapted to acute periodic stresses. And many organisms need random disturbing influences that contribute to their long-term stability. Large bodies of water often have good self-cleaning ability and restore their qualities after pollution as well as many terrestrial ecosystems. However, long-term violations can lead to severe and persistent negative consequences. In such cases, the evolutionary history of adaptation cannot help organisms — the compensation mechanisms are not unlimited. This is especially true for those cases where strongly toxic waste is discharged, which is constantly produced by an industrialized society and which were previously absent in the environment. If we cannot isolate these toxic wastes from global life support systems, then they will directly threaten our health and become the main limiting factor for humanity.

Anthropogenic stress is conventionally divided into two groups: acute and chronic.

The first is characterized by a sudden onset, a rapid rise in intensity and a short duration. In the second - violations of low intensity last for a long time or are repeated. Natural systems often have the ability to deal with acute stress. For example, a dormant seed strategy allows the forest to recover from felling. The consequences of chronic stress can be more severe, since the reactions to it are not so obvious. It may take years before changes in organisms are noticed. Thus, the relationship between cancer and smoking was identified only a few decades ago, although it existed a long time ago.

The threshold effect partially explains why some environmental problems appear as if unexpected. In fact, they accumulated for many years. For example, in the forests begins the mass death of trees after prolonged exposure to air pollutants. We begin to notice the problem only after the death of many forests in Europe and America. By this time, we were 10-20 years late and could not prevent the tragedy.

In the period of adaptation to chronic anthropogenic influences, the tolerance of organisms to other factors, for example, to diseases, decreases. Chronic stress is often associated with toxic substances, which, although in small concentrations, are constantly released into the environment.

The article “Poisoning America” (The Times magazine, September 22, 1980) provides the following data: “Of all human interventions in the natural order of things, not one has been growing at such an alarming rate as the creation of new chemical compounds. In the United States alone, cunning "alchemists" annually create about 1,000 new drugs. There are about 50,000 different chemicals on the market. Many of them undoubtedly bring great benefits to humans, but nearly 35,000 compounds used in the USA are definitely or potentially harmful to human health. ”

The danger, possibly catastrophic, is the pollution of groundwater and deep aquifers, which make up a significant proportion of the world's water resources. Unlike surface water, groundwater is not subject to natural processes of self-purification due to the lack of sunlight, fast currents and biotic components.

Fear is caused not only by harmful substances entering the water, soil and food. Millions of tons of hazardous compounds are released into the atmosphere. Only over America in the late 70's. Emitted: suspended particles - up to 25 million tons / year, SO 2 - up to 30 million tons / year, NO - up to 23 million tons / year.

We all contribute to air pollution by using cars, electricity, manufactured goods, etc. Air pollution is a clear negative feedback signal that can save society from death, as it is easily detected by everyone.

Solid waste management has long been considered a secondary concern. Until 1980, there were cases when residential blocks were built on former dumps of radioactive waste. Now, although with some delay, it became clear: the accumulation of waste limits the development of industry. Without the creation of technologies and centers for their removal, disposal and recycling, further progress of an industrial society is impossible. First of all, it is necessary to safely isolate the most toxic substances. The illegal practice of “night discharges” must be replaced by reliable isolation. Need to look for substitutes for toxic chemicals. With proper management, waste management and recycling can become a special industry that will create new jobs and contribute to the economy.

The solution to the problem of anthropogenic stress should be based on a holistic concept and requires a systematic approach. Attempts to deal with each pollutant as an independent problem are ineffective - they only transfer the problem from one place to another.

If in the next decade it is not possible to restrain the process of environmental degradation, it is likely that not a shortage of natural resources, but the impact of harmful substances will become a factor limiting the development of civilization.