But, unfortunately, his actions do not always have a positive impact, so we can observe anthropogenic environmental factors.
Conventionally, they are divided into indirect and direct, which in their totality gives an idea of the human influence on changes in the organic world. Shooting animals, fishing, etc. can be considered a striking example of direct influence. The picture with the indirect impact of human activity looks somewhat different, because here we will talk about the changes that are formed as a result of industrial interference in the natural course of natural processes.
Thus, anthropogenic factors are a direct or indirect result of human activity. Thus, in an effort to provide comfort and convenience for existence, a person changes the landscape, the chemical and physical composition of the hydrosphere and atmosphere, and affects the climate. In the end, one of the most serious interventions is considered as a result of which it instantly and significantly affects the health and vital signs of the person himself.
Anthropogenic factors are conditionally divided into several types: physical, biological, chemical and social. A person is in constant development, therefore, his activity is associated with ongoing processes using nuclear energy, mineral fertilizers, and chemicals. In the end, the person himself abuses bad habits: smoking, alcohol, drugs, etc.
Do not forget that anthropogenic factors have a huge impact on the environment of the person himself, and the mental and physical health of all of us directly depends on this. This has become especially noticeable in recent decades, when it became possible to note a sharp increase in anthropogenic factors. We have already witnessed the Earth, the disappearance of some species of animals and plants, the general reduction of the biological diversity of the planet.
Man is a biosocial being, therefore, it is possible to single out the social and its habitats. People are and remain, depending on the state of their body, in constant close contact with other individuals of wildlife. First of all, it can be said that anthropogenic factors can most positively affect the quality of human life, its development, but they can also lead to extremely adverse consequences, the responsibility for which should also be largely taken on.
I would like not to lose sight of the physical factors of the environment, which include humidity, temperature, radiation, pressure, ultrasound, and filtration. Needless to say, each biological species has its own optimal temperature for life and development, so this primarily affects the survival of many organisms. Humidity is an equally important factor, which is why the control of water in the cells of the body is considered a priority in the implementation of favorable living conditions.
Living organisms instantly react to changes in environmental conditions, and therefore it is so important to provide maximum comfort and favorable conditions for life. It depends only on us in what conditions we and our children will live.
Simple numbers say that 50% of the state of health depends on our lifestyle, the next 20% fall to the share of our environment, another 17% we owe to heredity, and only about 8% from health authorities. our nutrition, physical activity, communication with the outside world - these are the main conditions that affect the strengthening of the body.
In the course of the historical process of interaction between nature and society, there is a continuous increase in the influence of anthropogenic factors on the environment.
In terms of scale and degree of impact on forest ecosystems, one of the most important places among anthropogenic factors is occupied by final fellings. (The felling of the forest within the allowable cutting area and in compliance with ecological and forestry requirements is one of the necessary conditions for the development of forest biogeocenoses.)
The nature of the impact of final felling on forest ecosystems largely depends on the applied logging equipment and technology.
In recent years, new heavy multi-operational logging equipment has come to the forest. Its implementation requires strict adherence to the technology of logging operations, otherwise undesirable environmental consequences are possible: the death of undergrowth of economically valuable species, a sharp deterioration in the water-physical properties of soils, an increase in surface runoff, the development of erosion processes, etc. This is confirmed by the data of a field survey conducted by Soyuzgiproleskhoz specialists in some areas of our country. At the same time, there are many facts when the reasonable use of new technology in compliance with the technological schemes of logging operations, taking into account forestry and environmental requirements, ensured the necessary preservation of undergrowth and created favorable conditions for the restoration of forests with valuable species. In this regard, noteworthy is the experience of working with new equipment of loggers of the Arkhangelsk region, who, using the developed technology, achieve the preservation of 60% of viable undergrowth.
Mechanized logging significantly changes the microrelief, soil structure, its physiological and other properties. When using fellers (VM-4) or fellers and skidders (VTM-4) in the summer, up to 80-90% of the cutting area is mineralized; in conditions of hilly and mountainous terrain, such impacts on the soil increase surface runoff by a factor of 100, increase soil erosion, and, consequently, reduce its fertility.
Clearcutting can cause especially great harm to forest biogeocenoses and the environment in general in areas with an easily vulnerable ecological balance (mountainous regions, tundra forests, permafrost regions, etc.).
Industrial emissions have a negative impact on vegetation and especially on forest ecosystems. They affect plants directly (through the assimilation apparatus) and indirectly (change the composition and forest-growing properties of the soil). Harmful gases affect the above-ground organs of the tree and impair the vital activity of the microflora of the roots, as a result of which growth is sharply reduced. The predominant gaseous toxicant is sulfur dioxide - a kind of indicator of air pollution. Significant harm is caused by ammonia, carbon monoxide, fluorine, hydrogen fluoride, chlorine, hydrogen sulfide, nitrogen oxides, sulfuric acid vapors, etc.
The degree of damage to plants by pollutants depends on a number of factors, and above all on the type and concentration of toxicants, the duration and time of their exposure, as well as on the state and nature of forest plantations (their composition, age, density, etc.), meteorological and other conditions.
More resistant to the action of toxic compounds are middle-aged, and less resistant - mature and overmature plantations, forest crops. Hardwoods are more resistant to toxicants than conifers. High-density with abundant undergrowth and undisturbed tree structure is more stable than sparse artificial plantations.
The action of high concentrations of toxicants on the stand in a short period leads to irreversible damage and death; long-term exposure to low concentrations causes pathological changes in forest stands, and low concentrations cause a decrease in their vital activity. Forest damage is observed in almost any source of industrial emissions.
More than 200 thousand hectares of forests have been damaged in Australia, where up to 580 thousand tons of SO 2 falls annually with precipitation. In the FRG, 560,000 hectares were affected by harmful industrial emissions, in the GDR, 220, Poland, 379, and Czechoslovakia, 300,000 hectares. The action of gases extends over fairly considerable distances. Thus, in the United States, latent damage to plants was noted at a distance of up to 100 km from the emission source.
The harmful effect of emissions from a large metallurgical plant on the growth and development of forest stands extends to a distance of up to 80 km. Observations of the forest in the area of the chemical plant from 1961 to 1975 showed that, first of all, pine plantations began to dry out. Over the same period, the average radial increment fell by 46% at a distance of 500 m from the emission source and by 20% at 1000 m from the emission site. In birch and aspen, the foliage was damaged by 30-40%. In the 500-meter zone, the forest completely dried up 5-6 years after the onset of damage, in the 1000-meter zone - after 7 years.
In the affected area from 1970 to 1975, there were 39% of dried trees, 38% of severely weakened and 23% of weakened trees; at a distance of 3 km from the plant, there was no noticeable damage to the forest.
The greatest damage to forests from industrial emissions into the atmosphere is observed in areas of large industrial and fuel and energy complexes. There are also smaller-scale lesions, which also cause considerable harm, reducing the environmental and recreational resources of the region. This applies primarily to sparsely forested areas. To prevent or sharply reduce the damage to forests, it is necessary to implement a set of measures.
The allocation of forest lands for the needs of a particular sector of the national economy or their redistribution according to their purpose, as well as the acceptance of lands into the state forest fund, are one of the forms of influencing the state of forest resources. Relatively large areas are allocated for agricultural land, for industrial and road construction, significant areas are used by mining, energy, construction and other industries. Pipelines for pumping oil, gas, etc. stretch for tens of thousands of kilometers through forests and other lands.
The impact of forest fires on environmental change is great. The manifestation and suppression of the vital activity of a number of components of nature is often associated with the action of fire. In many countries of the world, the formation of natural forests is to some extent associated with the influence of fires, which have a negative impact on many forest life processes. Forest fires cause serious injuries to trees, weaken them, cause the formation of windblows and windbreaks, reduce the water protection and other useful functions of the forest, and promote the reproduction of harmful insects. Influencing all components of the forest, they make serious changes in forest biogeocenoses and ecosystems as a whole. True, in some cases, under the influence of fires, favorable conditions are created for the regeneration of the forest - the germination of seeds, the appearance and formation of self-seeding, especially pine and larch, and sometimes spruce and some other tree species.
On the globe, forest fires annually cover an area of up to 10-15 million hectares or more, and in some years this figure more than doubles. All this puts the problem of combating forest fires in the category of priorities and requires great attention to it from forestry and other bodies. The severity of the problem is increasing due to the rapid development of the national economic development of poorly inhabited forest areas, the creation of territorial production complexes, population growth and migration. This applies primarily to the forests of the West Siberian, Angara-Yenisei, Sayan and Ust-Ilim industrial complexes, as well as to the forests of some other regions.
Serious tasks for the protection of the natural environment arise in connection with the increase in the scale of the use of mineral fertilizers and pesticides.
Despite their role in increasing the yield of agricultural and other crops, high economic efficiency, it should be noted that if scientifically based recommendations for their use are not followed, negative consequences may also occur. With careless storage of fertilizers or poor incorporation into the soil, cases of poisoning of wild animals and birds are possible. Of course, the chemical compounds used in forestry and especially in agriculture in the fight against pests and diseases, unwanted vegetation, in the care of young plantations, etc., cannot be classified as completely harmless to biogeocenoses. Some of them have a toxic effect on animals, some, as a result of complex transformations, form toxic substances that can accumulate in the body of animals and plants. This obliges to strictly monitor the implementation of the approved rules for the use of pesticides.
The use of chemicals in the care of young forest plantations increases the risk of fire, often reduces the resistance of plantations to forest pests and diseases, and can have a negative impact on plant pollinators. All this should be taken into account when managing the forest with the use of chemicals; special attention should be paid in this case to water protection, recreational and other categories of forests for protective purposes.
Recently, the scale of hydrotechnical measures has been expanding, water consumption is increasing, and settling tanks are being installed in forest areas. Intensive water intake affects the hydrological regime of the territory, and this, in turn, leads to the violation of forest plantations (often they lose their water protection and water regulation functions). Flooding can cause significant negative consequences for forest ecosystems, especially during the construction of a hydroelectric power station with a system of reservoirs.
The creation of large reservoirs leads to the flooding of vast territories and the formation of shallow waters, especially in flat conditions. The formation of shallow waters and swamps worsens the sanitary and hygienic situation and adversely affects the natural environment.
Livestock grazing causes particular damage to the forest. Systematic and unregulated grazing leads to soil compaction, destruction of herbaceous and shrubby vegetation, damage to undergrowth, thinning and weakening of the forest stand, decrease in current growth, damage to forest plantations by pests and diseases. When undergrowth is destroyed, insectivorous birds leave the forest, since their life and nesting are most often associated with the lower tiers of forest plantations. Grazing causes the greatest danger in mountainous regions, since these territories are most susceptible to erosion processes. All this requires special attention and caution when using forest areas for pastures, as well as for haymaking. An important role in the implementation of measures for a more efficient and rational use of forest areas for these purposes is called upon to play the new rules for haymaking and grazing in the forests of the USSR, approved by the Decree of the Council of Ministers of the USSR of April 27, 1983 No.
Serious changes in the biogeocenosis are caused by the recreational use of forests, especially unregulated ones. In places of mass recreation, a strong compaction of the soil is often observed, which leads to a sharp deterioration in its water, air and thermal regimes, and a decrease in biological activity. As a result of excessive trampling of the soil, entire plantations or individual groups of trees can die (they are weakened to such an extent that they become victims of harmful insects and fungal diseases). Most often, the forests of green areas located 10-15 km from the city, in the vicinity of recreation centers and places of mass events, suffer from the recreational press. Some damage is caused to forests by mechanical damage, various kinds of waste, garbage, etc. Coniferous plantations (spruce, pine) are the least resistant to anthropogenic impact, deciduous plantations (birch, linden, oak, etc.) suffer to a lesser extent.
The degree and course of digression are determined by the resistance of the ecosystem to the recreational load. The resistance of the forest to recreation determines the so-called capacity of the natural complex (the maximum number of vacationers that can withstand the biogeocenosis without damage). An important measure aimed at preserving forest ecosystems and increasing their recreational properties is the comprehensive improvement of the territory with exemplary management of the economy here.
Negative factors act, as a rule, not in isolation, but in the form of certain interrelated components. At the same time, the action of anthropogenic factors often enhances the negative impact of natural ones. For example, the impact of toxic emissions from industry and transport is most often combined with an increased recreational load on forest biogeocenoses. In turn, recreation and tourism create conditions for the occurrence of forest fires. The action of all these factors sharply reduces the biological resistance of forest ecosystems to pests and diseases.
When studying the influence of anthropogenic and natural factors on the forest biogeocenosis, it must be taken into account that the individual components of the biogeocenosis are closely related both to each other and to other ecosystems. A quantitative change in one of them inevitably causes a change in all the others, and a significant change in the entire forest biogeocenosis inevitably affects each of its components. So, in the areas of constant action of toxic emissions from industry, the species composition of vegetation and wildlife is gradually changing. Of tree species, conifers are the first to be damaged and die. Due to the premature death of needles and a decrease in the length of shoots, the microclimate in the plantation changes, which affects the change in the species composition of herbaceous vegetation. Grasses begin to develop, contributing to the reproduction of field mice, systematically damaging forest crops.
Certain quantitative and qualitative characteristics of toxic emissions lead to disruption or even complete cessation of fruiting in most tree species, which adversely affects the species composition of birds. There are species of forest pests resistant to the action of toxic emissions. As a result, degraded and biologically unstable forest ecosystems are formed.
The problem of reducing the negative impact of anthropogenic factors on forest ecosystems through a whole system of protective and protective measures is inextricably linked with measures for the protection and rational use of all other components based on the development of an intersectoral model that takes into account the interests of the rational use of all environmental resources in their relationship.
The given brief description of the ecological relationship and interaction of all components of nature shows that the forest, like no other of them, has powerful properties to positively influence the natural environment and regulate its condition. Being an environment-forming factor and actively influencing all the processes of evolution of the biosphere, the forest is also affected by the relationship between all other components of nature unbalanced by anthropogenic impact. This gives grounds to consider the plant world and the natural processes occurring with its participation as a key factor that determines the general direction of the search for integral means of rational nature management.
Environmental schemes and programs should become an important means of identifying, preventing and solving problems in the relationship between man and nature. Such developments will help to solve these problems both in the country as a whole and in its individual territorial units.
Environmental factors are all environmental factors acting on the body. They are divided into 3 groups:
The best value of a factor for an organism is called optimal(optimum point), for example, the optimum air temperature for a person is 22º.
Anthropogenic factors
Human influences change the environment too quickly. This leads to the fact that many species become rare and die out. Biodiversity is decreasing because of this.
For example, consequences of deforestation:
- The habitat for the inhabitants of the forest (animals, fungi, lichens, grasses) is being destroyed. They may disappear completely (decreased biodiversity).
- The forest with its roots holds the top fertile soil layer. Without support, the soil can be blown away by the wind (you get a desert) or water (you get ravines).
- The forest evaporates a lot of water from the surface of its leaves. If you remove the forest, then the air humidity in the area will decrease, and the soil moisture will increase (a swamp may form).
1. Choose three options. What anthropogenic factors influence the size of the wild boar population in the forest community?
1) increase in the number of predators
2) shooting animals
3) feeding animals
4) the spread of infectious diseases
5) cutting down trees
6) severe weather in winter
Answer
2. Choose three correct answers from six and write down the numbers under which they are indicated. What anthropogenic factors influence the size of the May lily of the valley population in the forest community?
1) cutting down trees
2) increase in shading
4) collection of wild plants
5) low air temperature in winter
6) trampling the soil
Answer
3. Choose three correct answers from six and write down the numbers under which they are indicated. What processes in nature are classified as anthropogenic factors?
1) ozone depletion
2) daily change in illumination
3) competition in the population
4) accumulation of herbicides in the soil
5) relationship between predators and their prey
6) increased greenhouse effect
Answer
4. Choose three correct answers from six and write down the numbers under which they are indicated. What anthropogenic factors influence the number of plants listed in the Red Book?
1) destruction of their living environment
2) increase in shading
3) lack of moisture in summer
4) expansion of the areas of agrocenoses
5) sudden temperature changes
6) trampling the soil
Answer
5. Choose three correct answers from six and write down the numbers under which they are indicated. Anthropogenic environmental factors include
1) application of organic fertilizers to the soil
2) decrease in illumination in reservoirs with depth
3) precipitation
4) thinning pine seedlings
5) cessation of volcanic activity
6) shallowing of rivers as a result of deforestation
Answer
6. Choose three correct answers from six and write down the numbers under which they are indicated. What environmental disturbances in the biosphere are caused by anthropogenic interference?
1) the destruction of the ozone layer of the atmosphere
2) seasonal changes in the illumination of the land surface
3) decline in the number of cetaceans
4) the accumulation of heavy metals in the bodies of organisms near highways
5) accumulation of humus in the soil as a result of leaf fall
6) accumulation of sedimentary rocks in the depths of the oceans
Answer
1. Establish a correspondence between the example and the group of environmental factors that it illustrates: 1) biotic, 2) abiotic
A) overgrowing of the pond with duckweed
B) increase in the number of fish fry
C) eating fish fry by a swimming beetle
D) ice formation
E) flushing into the river of mineral fertilizers
Answer
2. Establish a correspondence between the process taking place in the forest biocenosis and the environmental factor that it characterizes: 1) biotic, 2) abiotic
A) the relationship between aphids and ladybugs
B) waterlogging of the soil
C) daily change in illumination
D) competition between species of thrushes
D) increase in air humidity
E) the effect of the tinder fungus on the birch
Answer
3. Establish a correspondence between examples and environmental factors that are illustrated by these examples: 1) abiotic, 2) biotic. Write the numbers 1 and 2 in the correct order.
A) an increase in atmospheric air pressure
B) change in the topography of the ecosystem caused by an earthquake
C) a change in the population of hares as a result of an epidemic
D) interaction between wolves in a pack
D) competition for territory between pine trees in the forest
Answer
4. Establish a correspondence between the characteristics of the environmental factor and its type: 1) biotic, 2) abiotic. Write the numbers 1 and 2 in the correct order.
A) ultraviolet rays
B) drying up of water bodies during a drought
C) animal migration
D) pollination of plants by bees
D) photoperiodism
E) a decrease in the number of squirrels in lean years
Answer
Answer
6f. Establish a correspondence between examples and environmental factors that are illustrated by these examples: 1) abiotic, 2) biotic. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) an increase in soil acidity caused by a volcanic eruption
B) change in the relief of the biogeocenosis of the meadow after the flood
C) change in the population of wild boars as a result of the epidemic
D) interaction between aspens in the forest ecosystem
E) competition for territory between male tigers
Answer
7f. Establish a correspondence between environmental factors and groups of factors: 1) biotic, 2) abiotic. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) daily fluctuations in air temperature
B) change in the length of the day
B) predator-prey relationship
D) symbiosis of algae and fungus in lichen
D) change in the humidity of the environment
Answer
Answer
2. Match the examples with the environmental factors illustrated by these examples: 1) Biotic, 2) Abiotic, 3) Anthropogenic. Write the numbers 1, 2 and 3 in the correct order.
A) autumn leaves
B) Planting trees in the park
C) The formation of nitric acid in the soil during a thunderstorm
D) Illumination
E) The struggle for resources in the population
E) Freon emissions into the atmosphere
Answer
3. Establish a correspondence between examples and environmental factors: 1) abiotic, 2) biotic, 3) anthropogenic. Write down the numbers 1-3 in the order corresponding to the letters.
A) change in the gas composition of the atmosphere
B) dispersal of plant seeds by animals
C) human draining of swamps
D) an increase in the number of consumers in the biocenosis
D) change of seasons
E) deforestation
Answer
Answer
Answer
1. Choose three correct answers out of six and write them down in the numbers under which they are indicated. The following factors lead to a decrease in the number of squirrels in a coniferous forest:
1) reduction in the number of birds of prey and mammals
2) cutting down coniferous trees
3) harvest of spruce cones after a warm dry summer
4) increase in activity of predators
5) outbreak of epidemics
6) deep snow cover in winter
Answer
Answer
Choose three correct answers from six and write down the numbers under which they are indicated. The destruction of forests in vast areas leads to
1) an increase in the amount of harmful nitrogen impurities in the atmosphere
2) violation of the ozone layer
3) violation of the water regime
4) change of biogeocenoses
5) violation of the direction of air flows
6) reduction in species diversity
Answer
1. Choose three correct answers from six and write down the numbers under which they are indicated. Specify biotic factors among environmental factors.
1) flood
2) competition between individuals of the species
3) lowering the temperature
4) predation
5) lack of light
6) mycorrhiza formation
Answer
2. Choose three correct answers from six and write down the numbers under which they are indicated. The biotic factors are
1) predation
2) forest fire
3) competition between individuals of different species
4) rise in temperature
5) mycorrhiza formation
6) lack of moisture
Answer
1. Choose three correct answers out of six and write down the numbers under which they are indicated in the table. Which of the following environmental factors are abiotic?
1) air temperature
2) greenhouse gas pollution
3) the presence of non-recyclable garbage
4) the presence of a road
5) illumination
6) oxygen concentration
Answer
2. Choose three correct answers out of six and write down the numbers under which they are indicated in the table. Abiotic factors include:
1) Seasonal bird migration
2) Volcanic eruption
3) The appearance of a tornado
4) Construction by beavers of platinum
5) The formation of ozone during a thunderstorm
6) Deforestation
Answer
3. Choose three correct answers out of six and write down in the answer the numbers under which they are indicated. The abiotic components of the steppe ecosystem include:
1) herbaceous vegetation
2) wind erosion
3) the mineral composition of the soil
4) rainfall mode
5) species composition of microorganisms
6) seasonal livestock grazing
Answer
Choose three correct answers from six and write down the numbers under which they are indicated. What environmental factors may be limiting for brook trout?
1) fresh water
2) oxygen content less than 1.6 mg/l
3) water temperature +29 degrees
4) water salinity
5) illumination of the reservoir
6) the speed of the river
Answer
1. Establish a correspondence between the environmental factor and the group to which it belongs: 1) anthropogenic, 2) abiotic. Write the numbers 1 and 2 in the correct order.
A) artificial irrigation of land
B) meteorite fall
B) plowing virgin land
D) spring flood of waters
D) building a dam
E) movement of clouds
Answer
2. Establish a correspondence between the characteristics of the environment and the environmental factor: 1) anthropogenic, 2) abiotic. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) deforestation
B) tropical showers
B) melting glaciers
D) forest plantations
D) draining swamps
E) an increase in the length of the day in spring
Answer
Choose three correct answers from six and write down the numbers under which they are indicated. The following anthropogenic factors can change the number of producers in an ecosystem:
1) collection of flowering plants
2) increase in the number of consumers of the first order
3) trampling of plants by tourists
4) decrease in soil moisture
5) cutting down hollow trees
6) increase in the number of consumers of the second and third orders
Answer
Read the text. Choose three sentences that describe abiotic factors. Write down the numbers under which they are indicated. (1) The main source of light on Earth is the Sun. (2) In photophilous plants, as a rule, strongly dissected leaf blades, a large number of stomata in the epidermis. (3) The humidity of the environment is an important condition for the existence of living organisms. (4) Plants evolved adaptations to maintain the body's water balance. (5) The content of carbon dioxide in the atmosphere is essential for living organisms.
Answer
Choose three correct answers from six and write down the numbers under which they are indicated. With a sharp decrease in the number of pollinating insects in the meadow over time
1) the number of insect pollinated plants is reduced
2) the number of birds of prey is increasing
3) the number of herbivores is increasing
4) the number of wind-pollinated plants increases
5) the water horizon of the soil changes
6) the number of insectivorous birds is decreasing
Answer
© D.V. Pozdnyakov, 2009-2019
Environmental environmental factors by origin are divided into:
1. Biotic.
2. Abiotic.
3. Anthropogenic.
Changes in the natural environment that have occurred as a result of economic and other human activities are due to anthropogenic factors. Trying to remake nature, in order to adapt it to his needs, man transforms the natural habitat of living organisms, influencing 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 the cultivation of fields, as well as the pollution of all earthly shells by transport and industrial waste. Physical factors include the use of nuclear energy, increased levels of noise and vibration as a result of human activities, in particular when using a variety of vehicles. Biological factors are food. They also include organisms that can inhabit the human body or those for which a person is potentially food. Social factors are determined by the coexistence of people in society and their relationships.
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 impact of any of them. For example, when arranging a highway or laying railway tracks through a forest, seasonal commercial hunting in a certain area, etc. Indirect impact is manifested by a change in natural landscapes due to human economic activity of low intensity over a long period of time. At the same time, the 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 leads to pollution of the environment with liquid and gaseous waste. In the future, trees in the nearby area die, animals are threatened with heavy metal poisoning, etc. The complex impact 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 habitation (rats, cockroaches, crows, 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 the new conditions of existence can survive in the changed landscape.
In the 20th and 11th centuries, anthropogenic factors have become of great importance in changing climatic conditions, the structure of soils and the composition of atmospheric air, salt and fresh water bodies, in reducing the area of \u200b\u200bforests, and in the extinction of many representatives of the flora and fauna.
Anthropogenic factors - a set of various human influences on inanimate and living nature. Only by their very physical existence, people have a noticeable impact on the environment: in the process of breathing, they annually release 1 10 12 kg of CO 2 into the atmosphere, and consume more than 5-10 15 kcal with food.
As a result of human impact, the climate, the surface topography, the 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 into the atmosphere from industrial enterprises can drastically change the regime of solar radiation dispersion in the atmosphere and reduce the heat input to the Earth's surface. The destruction of forests and other vegetation, the creation of large artificial reservoirs on former land areas increase the reflection of energy, and dust pollution, for example, snow and ice, on the contrary, increases absorption, which leads to their intensive melting.
To a much greater extent, the production activity of people affects the biosphere. 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 techno-ecosystems are created, cultivated plants are cultivated, animals are domesticated, etc.
Human impact can be direct or indirect. For example, deforestation and uprooting of forests 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 man. But, on the other hand, it creates new varieties of plants and animal breeds, increases their yield and productivity. Artificial migration of plants and animals also affects the life of ecosystems. So, rabbits brought to Australia multiplied so much that they caused great damage to agriculture.
The most obvious manifestation of anthropogenic influence on the biosphere is environmental pollution. The importance of anthropogenic factors is constantly growing, as man more and more subjugates nature.
Human activity is a combination of man's transformation of natural environmental factors for his own purposes and the creation of new ones that did not previously exist in nature. The smelting of metals from ores and the production of equipment are impossible without the creation of high temperatures, pressures, and powerful electromagnetic fields. Obtaining and maintaining high yields of agricultural crops requires the production of fertilizers and means of chemical protection of plants from pests and pathogens. Modern healthcare cannot be imagined without chemo- and physiotherapy.
The 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 affecting a person and his property: from firearms to means of mass physical, chemical and biological impact. In this case, we speak of 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 are inevitably formed. In conditions of accidents and catastrophes, these processes can be of a spasmodic nature with severe environmental and material consequences. Hence, it was necessary to create methods and means of protecting a person from dangerous and harmful factors, which has now been realized 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 impact 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 been 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 organisms die.
The zones of action of the ecological factor and the theoretical dependence of the vital activity of an 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 ecological optimum (lat. ortimus- the best). The values of the factor lying in the zone of oppression are called the ecological pessimum (the worst).
The minimum and maximum values of the factor at which death occurs are called respectively ecological minimum and ecological maximum
Any species of organisms, populations or communities are adapted, for example, to exist in a certain temperature range.
The property of organisms to adapt to existence in a particular range of environmental factors is called ecological plasticity.
The wider the range of the ecological factor within which a given organism can live, the greater its ecological plasticity.
According to the degree of plasticity, two types of organisms are distinguished: stenobiont (stenoeks) and eurybiont (euryeks).
Stenobiotic and eurybiont organisms differ in the range of ecological factors in which they can live.
Stenobiont(gr. stenos- narrow, cramped), or narrowly adapted, species are able to exist only with small deviations
factor from the optimal value.
Eurybiontic(gr. eirys- wide) are called widely adapted organisms that can withstand a large amplitude of fluctuations in the environmental factor.
Historically, adapting to environmental factors, animals, plants, microorganisms are distributed over various environments, forming the whole diversity of ecosystems that form the Earth's biosphere.
limiting factors. The concept of limiting factors is based on two laws of ecology: the law of the 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, discovered that the yield does not depend on those nutrients that are required in large quantities and are present in abundance (for example, CO 2 and H 2 0 ), but from those that, although the plant needs them in smaller quantities, are practically absent in the soil or inaccessible (for example, phosphorus, zinc, boron).
Liebig formulated this pattern as follows: "The growth of a plant depends on the nutrient element that is present in the minimum amount." Later this conclusion became known as Liebig's law of the minimum and has been extended to many other environmental factors. The development of organisms can be limited or limited by heat, light, water, oxygen, and other factors, if their value corresponds to the ecological minimum. For example, tropical fish angelfish die if the water temperature drops below 16 °C. And the development of algae in deep-sea ecosystems is limited by the depth of penetration of sunlight: there are no algae in the bottom layers.
Liebig's law of the minimum in general terms can be formulated as follows: the growth and development of organisms depend, first of all, on those environmental factors whose values approach the ecological minimum.
Research has shown that the law of the minimum has two limitations that should be taken into account in practical application.
The first limitation is that Liebig's law is strictly applicable only under conditions of a stationary state of the system. For example, in a certain body of water, algae growth is naturally limited by a lack of phosphate. Nitrogen compounds are contained in water in excess. If wastewater with a high content of mineral phosphorus is discharged into this reservoir, then the reservoir may “bloom”. This process will progress until one of the elements is used up to the limiting minimum. Now it could be nitrogen if the phosphorus continues to flow. At the transitional moment (when there is still enough nitrogen, and there is already enough phosphorus), the minimum effect is not observed, i.e., none of these elements affects the growth of algae.
The second limitation is related to the interaction of several factors. Sometimes the body is able to replace the deficient element with another chemically close one. So, in places where there is a lot of strontium, in mollusk shells, 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. Therefore, a low zinc concentration will limit plant growth less in shade than in bright light. In these cases, the limiting effect of even an insufficient amount of one or another element may not manifest itself.
Law of Tolerance(lat . tolerance- patience) was discovered by the English biologist W. Shelford (1913), who drew attention to the fact that not only those environmental factors, the values of which are minimal, but also those that are characterized by an ecological maximum, can limit the development of living organisms. Too much heat, light, water, and even nutrients can be just as damaging as too little. The range of the environmental factor between the minimum and maximum W. Shelford called limit of tolerance.
The tolerance limit describes the amplitude of factor fluctuations, which ensures the most complete existence of the population. Individuals may have slightly different tolerance ranges.
Later, tolerance limits were established 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 distributed everywhere because populations have a certain tolerance limit in relation to fluctuations in environmental environmental factors.
W. Shelford's law of tolerance is formulated as follows: the growth and development of organisms depend primarily on those environmental factors whose values approach the ecological minimum or ecological maximum.
The following has been established:
Organisms with a wide range of tolerance to all factors are widely distributed in nature and are often cosmopolitan, such as 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 tolerant to lack of food than to lack of water, i.e., the limit of tolerance for water is narrower than for food;
If 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 body's potential to adapt to this factor. This is explained by the fact that in nature the limits of tolerance in relation to the physical conditions of the environment can be narrowed by biotic relations: competition, lack of pollinators, predators, etc. Any person better realizes his potential under favorable conditions (gatherings of athletes for special training before important competitions, ). The potential ecological plasticity of the organism, determined in the laboratory, is greater than the realized possibilities in natural conditions. Accordingly, potential and realized ecological niches are distinguished;
The limits of tolerance in breeding individuals and offspring are less than in adults, i.e. females during the breeding season and their offspring are less hardy 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 offspring and respect for motherhood are dictated by the laws of nature. Unfortunately, sometimes social "achievements" contradict these laws;
Extreme (stress) values of one of the factors lead to a decrease in the tolerance limit for other factors. If heated water is dumped into the river, then fish and other organisms spend almost all their energy coping with stress. They do not have enough energy to obtain food, protection from predators, reproduction, which leads to gradual extinction. Psychological stress can also cause many somatic (gr. soma- body) diseases not only in humans, but also in some animals (for example, in dogs). At stressful values of the factor, adaptation to it becomes more and more “expensive”.
Many organisms are able to change 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 water. This adaptation to the slow change of the factor is a useful protective property. But it can also be dangerous. Unexpected, without warning signals, even a small change can be critical. There comes a threshold effect: the "last straw" can be fatal. For example, a thin twig can break a camel's already overstretched back.
If the value of at least one of the environmental factors approaches a minimum or maximum, the existence and prosperity of an organism, population or community becomes dependent on this life-limiting factor.
A limiting factor is any environmental factor that approaches or exceeds the extreme values of the tolerance limits. Such strongly deviating factors become 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 lies in the fact 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. It is on these factors that the ecologist should focus his attention in the study of ecosystems and their management. For example, the oxygen content in terrestrial habitats is high and it is so available that it almost never serves as a limiting factor (with the exception of high altitudes and anthropogenic systems). Oxygen is of little interest to terrestrial ecologists. 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 also determine the geographic range of the species. Thus, the movement of organisms to the south is limited, as a rule, by a lack of heat. Biotic factors also often limit the distribution of certain organisms. For example, figs brought from the Mediterranean to California did not bear fruit there until they guessed to bring there a certain type of wasp - the only pollinator of this plant. The identification of limiting factors is very important for many activities, especially agriculture. With a targeted impact on the limiting conditions, it is possible to quickly and effectively increase the yield of plants and the productivity of animals. So, when wheat is grown on acidic soils, no agronomic measures will have an effect if liming is not used, which will reduce the limiting effect of acids. Or if you grow corn on soils with a very low phosphorus content, then even with enough water, nitrogen, potassium and other nutrients, it stops growing. Phosphorus is the limiting factor in this case. And only phosphate fertilizers can save the crop. Plants can also die from too much water or too much 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 organism and in different situations, various factors act as limiting factors. Therefore, only skillful regulation of the conditions of existence can give effective management results.
Interaction and compensation of factors. In nature, environmental factors do not act independently of each other - they interact. Analysis of the influence of one factor on an organism or community is not an end in itself, but a way of assessing the relative importance of various conditions acting together in real ecosystems.
Joint influence of factors can be considered on the example of the dependence of mortality of crab larvae on temperature, salinity and the presence of cadmium. In the absence of cadmium, the ecological optimum (minimal 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, then the ecological optimum is shifted: the temperature lies in the range from 13 to 26 ° C, and the salinity is from 25 to 29%. The limits of tolerance are also changing. The difference between the ecological maximum and minimum for salinity after the addition of cadmium decreases from 11 - 47% to 14 - 40%. The tolerance limit for the temperature factor, on the contrary, expands from 9 - 38 °C to 0 - 42 °C.
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: maritime and continental.
Reservoirs soften the land climate, since water has a high specific heat of fusion and heat capacity. Therefore, the maritime climate is characterized by less sharp fluctuations in temperature and humidity than the continental one.
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 climogram graphs, which make it possible to visually compare different years and regions and predict the production of plants or animals for certain climatic conditions.
Organisms are not slaves to the environment. They adapt to the conditions of existence and change them, that is, they 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 torphe - form, outline) features adapted to local conditions. For example, in animals, the ears, tails, paws are the shorter, and the body is the more massive, the colder the climate.
This pattern is called Allen's 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 stocky, its ears are much shorter; and the arctic fox - 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 arising in the process of adaptation are often genetically fixed. At the community level, compensation of factors can be carried out by changing species along 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 make the most of favorable conditions.
The most striking example is the behavior of organisms depending on the length of the day - photoperiod. The amplitude of the day length increases with geographic latitude, which allows organisms to take into account not only the season, but also the latitude of the area. The photoperiod is a "time switch" 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 the biological clock and serves as a universal mechanism for regulating functions over time. The biological clock connects the rhythms of environmental factors with physiological rhythms, allowing organisms to adapt to the daily, seasonal, tidal and other dynamics of factors.
By changing the photoperiod, it is possible to cause changes in body functions. So, flower growers, changing the light regime in greenhouses, get off-season flowering of plants. If after December you immediately increase the length of the day, then this can cause phenomena that occur in spring: flowering of plants, molting in animals, etc. In many higher organisms, adaptations to the photoperiod are fixed genetically, i.e., the biological clock can work even in the absence of a regular daily or seasonal dynamics.
Thus, the meaning of the analysis of environmental conditions is not to compile 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 it is 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 are more often evaluated only negatively. Research over the past 50 years has shown that natural fires may be part of the climate in many terrestrial habitats. They influence the evolution of flora and fauna. Biotic communities have "learned" to compensate for this factor and adapt to it like temperature or humidity. Fire can be considered and studied as an ecological 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, also 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 a fire has not occurred at least once in 50 years. The most common cause of wildfires is a lightning strike.
Fires are of different types and lead to different consequences.
Mounted or "wild" fires are usually very intense and cannot be contained. They destroy the crown of trees and destroy all soil organic matter. Fires of this type have a limiting effect on almost all organisms in the community. It will take many years for the site to recover again.
Ground fires are completely different. They have a selective effect: for some organisms they 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 man. For example, planned burning in the forest is undertaken in order to eliminate competition for a valuable breed of swamp pine from deciduous trees. Swamp pine, unlike hardwoods, 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 pine, as well as cereals and legumes. This leads to the oppression of partridges and small herbivores. Therefore, virgin pine forests with abundant game are ecosystems of the "fire" type, i.e., 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.
With nitrogen-fixing legumes, a small fire is even useful. Burning is carried out in the evening, so that at night the fire is extinguished by dew, and the narrow front of the fire can be easily stepped over. In addition, small ground fires complement the action of bacteria to convert 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. Planned burning is an example of managing a natural ecosystem with the help of a limiting environmental factor.
Whether the possibility of fires should be completely eliminated or whether fire should be used as a management factor should depend entirely on what type of community is desired in the area. The American ecologist G. Stoddard (1936) was one of the first to "defend" controlled planned burning to increase the production of valuable wood and game even in those days when, from the point of view of foresters, any fire was considered harmful.
The close relationship between burnout and grass composition plays a key role in maintaining the amazing diversity of antelopes and their predators in the East African savannas. Fires have a positive effect on many cereals, since their growth points and energy reserves are underground. After the dry aerial parts burn out, the batteries quickly return to the soil and the grasses grow luxuriantly.
The question “to burn or not to burn”, of course, can be confusing. By negligence, a person is often the cause of an increase in the frequency of destructive "wild" fires. The struggle for fire safety in forests and recreation areas is the other side of the problem.
In no case shall a private person have 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 occasional disruptive influences that contribute to their long-term stability. Large bodies of water often have a good ability to self-cleanse and recover from pollution in the same way as many terrestrial ecosystems. However, long-term violations can lead to pronounced and persistent negative consequences. In such cases, the evolutionary history of adaptation cannot help organisms - compensation mechanisms are not unlimited. This is especially true when highly toxic wastes are dumped, which are constantly produced by an industrialized society and which were previously absent in the environment. If we fail to isolate these toxic wastes from global life support systems, they will directly threaten our health and become a major 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 case, violations of low intensity continue for a long time or are repeated. Natural systems often have sufficient capacity to cope with acute stress. For example, the dormant seed strategy allows the forest to regenerate after clearing. The consequences of chronic stress can be more severe, as reactions to it are not so obvious. It may take years for changes in organisms to be noticed. Thus, the connection between cancer and smoking was revealed only a few decades ago, although it existed for a long time.
The threshold effect partly explains why some environmental problems appear unexpectedly. In fact, they have accumulated over the years. For example, in forests, mass tree death begins 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 late by 10-20 years and could not prevent the tragedy.
During the period of adaptation to chronic anthropogenic impacts, the tolerance of organisms to other factors, such as diseases, also decreases. Chronic stress is often associated with toxic substances, which, although in small concentrations, are constantly released into the environment.
The article "Poisoning America" (Times magazine, 09/22/80) provides the following data: "Of all human interventions in the natural order of things, none is growing at such an alarming rate as the creation of new chemical compounds. In the US alone, cunning "alchemists" create about 1,000 new drugs every year. There are about 50,000 different chemicals on the market. Many of them are undeniably of great benefit to humans, but nearly 35,000 compounds in use in the US are definitely or potentially harmful to human health.”
The danger, perhaps catastrophic, is the pollution of groundwater and deep aquifers, which make up a significant proportion of the world's water resources. Unlike surface groundwater, it is not subject to natural self-purification processes due to the lack of sunlight, fast flow and biotic components.
Concerns are caused not only by harmful substances that enter the water, soil and food. Millions of tons of hazardous compounds are released into the atmosphere. Only over America in the late 70s. 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 through the use of cars, electricity, manufactured goods, etc. Air pollution is a clear negative feedback signal that can save society from destruction, as it is easily detected by everyone.
The treatment of solid waste has long been considered a minor matter. Until 1980, there were cases when residential areas were built on former radioactive waste dumps. 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, neutralization and recycling, further progress of industrial society is impossible. First of all, it is necessary to safely isolate the most toxic substances. The illegal practice of "night discharges" should be replaced by reliable isolation. We need to look for substitutes for toxic chemicals. With the right leadership, waste disposal 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. Attempting to treat each pollutant as a problem in itself is ineffective - it only moves the problem from one place to another.
If in the next decade it is not possible to contain the process of deterioration of the quality of the environment, then it is quite likely that not a shortage of natural resources, but the impact of harmful substances will become a factor limiting the development of civilization.
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