All living nature that surrounds us - animals, plants, mushrooms and other living organisms - is a whole biocenosis or part, for example, of a regional biocenosis or the biocenosis of a separate part. All biocenoses have different conditions and may differ in the types of organisms and plants.

In contact with

Biocenosis is community, a set of living organisms in the nature of a certain territorial area. The concept also implies environmental conditions. If a separate territory is taken, then within its boundaries there should be approximately the same climate. The biocenosis can extend to the inhabitants of land, water and.

All organisms in the biocenosis are closely related to each other. There are food connections, or with the habitat and distribution. Some populations use others to build their own shelters.

There is also a vertical and horizontal structure of the biocenosis.

Attention! The biocenosis can be natural or artificial, that is, man-made.

In the 19th century, biology was actively developing, like other branches of science. Scientists continued to describe living organisms. In order to simplify the task of describing groups of organisms that inhabit a particular territory, Karl August Moebius was the first to introduce the term “biocenosis”. This happened in 1877.

Signs of biocenosis

There are the following signs of biocenosis:

1. There is a close relationship between the populations.
2. The biotic connection between all components is stable.
3. Organisms adapt to each other and in groups.
4. A biological cycle is observed in this area.
5. Organisms interact with each other, so they are mutually necessary.

Components

The components of a biocenosis are all living organisms. They are divided into three large groups:

• consumers - consumers of finished substances (for example, predators);
• producers - can produce nutrients on their own (for example, green plants);
• decomposers are those organisms that are the final link in the food chain, that is, they decompose dead organisms (for example, fungi and bacteria).

Components of biocenosis

Abiotic part of the biocenosis

Abiotic environment- this is climate, weather, relief, landscape, etc., that is, this is the inanimate part. Conditions will differ on different parts of the continents. The harsher the conditions, the fewer species will be present in the area. The equatorial belt has the most favorable climate - warm and humid, so endemic species are most often found in such areas (many of them can be found on the Australian mainland).

A separate area of ​​the abiotic environment called a biotope.

Attention! The richness of species within the biocenosis depends on the conditions and nature of the abiotic environment.

Types of biocenosis

In biology, types of biocenosis are classified according to the following characteristics.

By spatial location:

• Vertical (tiered);
• Horizontal (mosaic).

By origin:

• Natural (natural);
• Artificial (man-made).

By connection type species within the biocenosis:

• Trophic (food chains);
• Factory (arrangement of habitats of an organism with the help of dead organisms);
• Topical (individuals of one species serve as habitats or influence the lives of other species);
• Phoric (participation of some species in the distribution of the habitat of others).

Spatial structure of the biocenosis

Natural biocenosis

Natural biocenosis is characterized by the fact that it has a natural origin. A person does not interfere with the processes occurring in it. For example: the Volga River, forest, steppe, meadow, mountains. Unlike artificial ones, natural ones have a larger scale.

If a person interferes with the natural environment, the balance between species is disrupted. Irreversible processes are taking place - the extinction and disappearance of some species of plants and animals, they are indicated in "". Those species that are on the verge of extinction are listed in the Red Book.

Let's look at examples of natural biocenosis.

River

The river is natural biocenosis. It is home to various animals, plants and bacteria. The views will vary depending on the location of the river. If the river is located in the north, then the diversity of the living world will be poor, but if it is closer to the equator, then the abundance and diversity of species living there will be rich.

Inhabitants of river biocenoses: beluga, perch, crucian carp, pike, sterlet, herring, ide, bream, pike perch, ruffe, smelt, burbot, crayfish, asp, carp, carp, catfish, roach, track, silver carp, sabrefish, various freshwater algae and many other living organisms.

Forest

Forest is example of a natural look. The forest biocenosis is rich in trees, shrubs, grass, animals that live in the air, on the ground and in the soil. Here you can find mushrooms. Various bacteria also live in the forest.

Representatives of the forest biocenosis (fauna): wolf, fox, elk, wild boar, squirrel, hedgehog, hare, bear, elk, tit, woodpecker, chaffinch, cuckoo, oriole, black grouse, wood grouse, thrush, owl, ant, ladybug, pine silkworm, grasshopper, tick and many other animals.

Representatives of the forest biocenosis (plant world): birch, linden, maple, elderberry, corydalis, oak, pine, spruce, aspen, lily of the valley, kupir, strawberry, blackberry, dandelion, snowdrop, violet, forget-me-not, lungwort, hazel and many other plants.

The forest biocenosis is represented by the following mushrooms: boletus, boletus, porcini mushroom, toadstool, fly agaric, oyster mushroom, puffball, chanterelle, oiler, honey fungus, morel, russula, champignon, saffron milk cap, etc.

Natural and artificial biocenosis

Artificial biocenosis

An artificial biocenosis differs from a natural one in that it created by human hands to satisfy their needs or the needs of the whole society. In such systems, a person himself designs the required conditions. Examples of such systems are: garden, vegetable garden, field, forest plantation, apiary, aquarium, canal, pond, etc.

The emergence of artificial environments led to the destruction of natural biocenoses and the development of agriculture and the agricultural sector of the economy.

Examples of artificial classification

For example, in a field, greenhouse, garden or vegetable garden, a person grows cultivated plants (vegetables, grain crops, fruitful plants, etc.). So that they don't die, certain conditions are created: Irrigation systems for watering, lighting. The soil is saturated with the missing elements with the help of fertilizers. Plants are treated with chemicals to protect them from being eaten by pests, etc.

Forest belts are planted near fields, on the slopes of ravines, near railways and roads. Near the fields they are needed in order to reduce evaporation and retain snow in the spring, i.e. to control the water regime of the earth. Trees also protect seeds from being blown away by the wind and protect the soil from erosion.

Trees are planted on the slopes of ravines in order to prevent and slow down their growth, since the roots will hold the soil.

Trees along roads are necessary to prevent snow, dust, and sand from driving transport routes.

Attention! Man creates artificial biocenoses in order to improve the life of society. But excessive interference with nature is fraught with consequences.

Horizontal structure of biocenosis

The horizontal structure of a biocenosis differs from the tiered one in that the abundance of species living on its territory changes not vertically, but horizontally.

For example, we can consider the most global example. The diversity, abundance and richness of the living world varies by zone. In the zone of arctic deserts, in the arctic climate zone, the flora and fauna are sparse and poor. As we approach the tropical forest zone, in the tropical climate zone, the number and diversity of species will increase. So we were able to trace changes in the number of species within the biocenosis, and even changes in their structure (since they have to adapt to different climate conditions). This is a natural mosaic.

And artificial mosaic occurs under human influence on the environment. For example, deforestation, sowing meadows, draining swamps, etc. In a place where people have not changed the conditions, the organisms will remain. And those places where conditions have changed will be inhabited by new populations. The components of the biocenosis will also differ.

Biocenosis

The concept of biogeocenosis and ecosystem

Conclusion

Let's summarize: biocenosis has different classifications depending on its origin, relationships between organisms and location in space. They differ in territorial scale and the species that live within their boundaries. Signs of biocenosis can be classified separately for each area.

In the process of everyday life, not every person notices his interaction with various people. Rushing to work, it is unlikely that anyone, except perhaps a professional ecologist or biologist, will pay special attention to the fact that he crossed a square or park. Well, I passed and passed, so what? But this is already a biocenosis. Each of us can remember examples of such involuntary but constant interaction with ecosystems, if only we think about it. Let's try to consider in more detail the question of what biocenoses are, what they are like and what they depend on.

What is biocenosis?

Most likely, few people remember that they studied biocenoses at school. 7th grade, when they covered this topic in biology, is far in the past, and completely different events are remembered. Let us remind you what a biocenosis is. This word is formed by merging two Latin words: “bios” - life and “cenosis” - general. This term denotes a collection of microorganisms, fungi, plants and animals living in the same territory, interconnected and interacting with each other.

Any biological community includes the following components of the biocenosis:

• microorganisms (microbiocenosis);
• vegetation (phytocenosis);
• animals (zoocenosis).

Each of these components plays an important role and can be represented by individuals of different species. However, it should be noted that phytocenosis is the leading component that determines microbiocenosis and zoocenosis.

When did this concept appear?

The concept of “biocenosis” was proposed by the German hydrobiologist Möbius at the end of the 19th century, when he studied the habitats of oysters in the North Sea. During the study, he found that these animals can only live in strictly defined conditions, characterized by depth, flow speed, salinity and temperature of the water. In addition, Möbius noted that, together with oysters, strictly defined species of marine plants and animals live in the same territory. Based on the data obtained, in 1937 the scientist introduced the concept we are considering to denote the union of groups of living organisms living and coexisting in the same territory, due to the historical development of species and the long-term modern concept of “biocenosis”, biology and ecology interpret somewhat differently.

Classification

Today there are several signs according to which a biocenosis can be classified. Examples of classification based on size:

• macrobiocenosis (sea, mountain ranges, oceans);
• mesobiocenosis (swamp, forest, field);
• microbiocenosis (flower, old stump, leaf).

Biocenoses can also be classified depending on their habitat. The following three types are recognized as the main ones:

• nautical;
• freshwater;
• ground.

Each of them can be divided into subordinate, smaller and local groups. Thus, marine biocenoses can be divided into benthic, pelagic, shelf and others. Freshwater biological communities are river, swamp and lake. Terrestrial biocenoses include coastal and inland, mountain and lowland subtypes.

The simplest classification of biological communities is their division into natural and artificial biocenoses. Among the former, there are primary ones, formed without human influence, as well as secondary ones, which have undergone changes due to the influence of natural elements or the activities of human civilization. Let's take a closer look at their features.

Natural biological communities

Natural biocenoses are associations of living beings created by nature itself. Such communities are natural systems that form, develop and function according to their own special laws. The German ecologist W. Tischler identified the following features characterizing such formations:

1. Communities arise from ready-made elements, which can be either representatives of individual species or entire complexes.

2. Parts of the community may be replaceable. Thus, one species can be supplanted and completely replaced by another that has similar requirements for living conditions, without negative consequences for the entire system.

3. Due to the fact that in the biocenosis the interests of different species are opposite, the entire supraorganismal system is based and exists thanks to the balancing of forces directed in opposite directions.

In addition, in biological communities there are edificators, that is, animal or plant species that create the necessary conditions for life for other creatures. So, for example, in steppe biocenoses the most powerful edificator is feather grass.

In order to assess the role of a particular species in the structure of a biological community, quantitative indicators are used, such as its abundance, frequency of occurrence, Shannon diversity index and species saturation.

Everyone knows that on a certain piece of land or body of water a certain number of organisms, plants and animals live together. Their totality, as well as the relationship and interaction among themselves and with other abiotic factors, is usually called biocenosis. This word is formed by merging two Latin words “bios” - life and “cenosis” - general. Any biological community consists of such components of bioceosis as:

• — zoocenosis;
• - phytocenosis;
• microorganisms - microbiocenosis.

It should be noted that phytocenosis is the dominant component that determines zoocenosis and microbiocenosis.

Origin of the concept “biocenosis”

At the end of the 19th century, the German scientist Karl Mobius studied the habitats of oysters in the North Sea. During the study, he found that these organisms can only exist in specific conditions, which include depth, current speed, salt content and water temperature. In addition, he noted that strictly defined species of marine life live together with oysters. So in 1877, with the publication of his book “Oysters and Oyster Farming,” the term and concept of biocenosis appeared in the scientific community.

Classification of biocenoses

Today there are a number of characteristics according to which biocenosis is classified. If we are talking about systematization based on sizes, then it would be:

• macrobiocenosis, which studies mountains, seas and oceans;
• mesobiocenosis - forests, swamps, meadows;
• microbiocenosis - a single flower, leaf or stump.

Biocenoses can also be classified depending on their habitat. Then the following types will be distinguished:

• marine;
• freshwater;
• ground.

The simplest systematization of biological communities is their division into natural and artificial biocenoses. The first include primary ones, formed without human influence, as well as secondary ones, which were influenced by natural elements. The second group includes those who have undergone changes due to anthropogenic factors. Let's take a closer look at their features.

Natural biocenoses

Natural biocenoses are associations of living beings created by nature itself. Such communities are historically established systems that are created, develop and function according to their own special laws. The German scientist W. Tischler outlined the following characteristics of such formations:

• Biocenoses arise from ready-made elements, which can be either representatives of individual species or entire complexes;
• parts of the community can be replaced by others. So one species can be replaced by another, without negative consequences for the entire system;
• taking into account the fact that in a biocenosis the interests of different species are opposite, then the entire supraorganismal system is founded and maintained due to the action of the counterforce;
• each natural community is built through the quantitative regulation of one species by another;
• the dimensions of any supraorganismal systems depend on external factors.

Artificial biological systems

Artificial biocenoses are formed, maintained and regulated by humans. Professor B.G. Johannsen introduced into ecology the definition of anthropocenosis, that is, a natural system deliberately created by man. This could be a park, square, aquarium, terrarium, etc.

Among man-made biocenoses, agrobiocenoses are distinguished - these are biosystems created to obtain food. These include:

• reservoirs;
• channels;
• ponds;
• pastures;
• fields;
• forest plantings.

A typical feature is the fact that it is unable to survive for a long period of time without human intervention.

The concept of biocenosis includes terms such as ecology: biology, ecosystem, biocenosis, biotope, biogeocenosis. What do all these terms mean? It turns out that all this is not so difficult. You just need to translate these words from Greek.

Scientists from different countries and nationalities contributed to the creation and development of these sciences, and they chose Greek as a common language and convenient for communication.

The rapid development of these sciences occurred at the beginning of the 19th century. The term "biology" was proposed simultaneously by Friedrich Burdach, Gottfried Reinhold Treviranus and Jean Baptiste Lemarck. The term "ecology" in 1866 was reflected in the book "General Morphology of Organisms" by Ernst Heinrich Haeckel.

Karl August Mobius continued the development of science and in 1877 introduced the term “biocenosis” to describe living organisms inhabiting a certain territory. With the introduction of the term biocenosis, biotope received its definition. It was first designated by the same Ernst Heinrich Haeckel, and developed and introduced in 1908 by the professor of the Berlin Zoological Museum F. Dahl.

The term biocenosis has found its application in literature in Russian and German. In English-speaking countries, the concept of “community” is used, which is not exactly the same thing.

In 1942, Professor Sukachev developed the doctrine of biogeocenosis. Biogeocenosis and biocenosis essentially mean the same thing; however, the term is rarely used in the world scientific literature, but is sometimes found in German-language publications.

Definition of terms

Now let’s say what the above terms mean.

What is biocenosis in biology? Let's give the first definition. Biocenosis– these are all animals, plants and microorganisms that exist over a long period of time, in a certain space and under the influence of the natural environment.

A certain relatively homogeneous space is understood as a biotope. That is, an area of ​​land, sea or inland water with stable environmental influences and climatic conditions. These factors determine the species composition of the animal, plant and microorganisms living on it.

The totality of a biocenosis and a biotope is already an ecosystem, which consists of the entire number of species of living organisms, their habitat and the connections that arise between them, the effects on each other and the exchange of energy.

Thus, ecosystem, biocenosis and biotope are concepts where each subsequent one is an integral and integral part of the previous one.

Pictures of biocenosis best characterize these concepts.

Separation of biocenosis by type and saturation

According to its structure, the biocenosis can be divided into: species, spatial or vertical and mosaic or horizontal.

First of all, species characterizes the quantitative diversity of species of living organisms living in it, and their total mass. In other words, biodiversity and biomass.

The variety of species of animals and birds, fish and shellfish, plants and microorganisms, as well as their quantity, indicates its wealth or poverty. It also depends on the time when it was formed.

Species diversity or richness decreases as one approaches the Earth's poles. The richest flora and fauna are near the equator.

Biocenoses created by man are incomparably poorer than natural ones and require constant additional measures to maintain them. That is, there are natural and artificial biocenoses.

Another interesting fact is that the smaller the size of a living organism, the greater the number of these individuals.

A distinction can be made by the scale of the biocenosis or the area it occupies. It could be a forest or a single tree, even a stump, a small meadow or an entire desert, a small lake or ocean.

A specific “biocenosis” includes not only living organisms that constantly exist in it, but also those that stay for some, even a short time. For example, migratory birds, fish coming to spawn, insects breeding in water, and so on.

We can give examples typical for biocenosis.

On one hectare of land in the Amazon rainforest, up to 400 trees of more than 90 species can grow. While in the temperate zone of the European continent there will be no more than 10, and in the taiga even less - up to 5.

The same is true with the animal world. In Alaska, there are several times fewer species of animals and birds than in Panama, Colombia.

Separation by spatial factor

In space, the biocenosis should be divided into vertical and horizontal.

The first is characterized by tiers, that is, how high above the ground the habitat of living organisms is. For vegetation, it is divided into woody, shrubby, herbaceous and moss-lichen. For insects, the tiers are distributed in the same way as for the inhabitants of the soil: the surface layer of the earth, mosses, grass and a high tier. For animals and birds, the tiers are not so clearly demarcated. In the horizontal plane it has the character of heterogeneity and resembles a mosaic.

Dimensions of biocenosis and its conditionality

What determines the size of the biocenosis? It may seem that these dimensions can be chosen arbitrarily. But we should not forget that it is characterized by stability and self-regulation. This indicates the existence of a closed biological chain, which begins with the synthesis of organic matter from inorganic matter, and ends with the same.

In other words, the plant synthesizes organic matter from solar energy and soil minerals. They are eaten by animals. Herbivores are eaten by predators, and everything that dies is processed by worms and bacteria. Re-forming inorganic compounds. The circuit is closed.

This eating of one living organism by another is called a trophic chain.

But there is one extraneous factor involved here. – abiotic. The word is again of Greek origin. The prefix “a” in it has the character of negation. That is, a non-biological factor or, more precisely, a complex of factors and conditions of the inorganic environment that influences a living organism. These are sunlight, temperature, wind, air, precipitation and pressure.

Some of them can be clarified. For example: length of daylight hours and intensity of solar radiation, contamination of soil or water with chemical or toxic substances, droughts or dust storms, underwater depths or atmospheric rarefaction of high mountains, abnormally high or low temperatures.

Such an abiotic environment underlies the creation of a homogeneous space - a biotope, which is occupied by a biocenosis. And yet, there are no clear boundaries between them, and they turn into one another. In such border zones the diversity and density of living organisms is much greater. This effect is called edge effect.

The set of abiotic factors in which a particular biological species lives is called an ecological niche.

Stability and adaptability

The biocenosis has a certain stability, but under the influence of various factors it also adapts and adapts well.

Its stability can be illustrated by the fact that even in the richest of them, all species are scarce. This also applies to flora and fauna.

Our concept of biocenosis is formed on the basis of its characteristics according to various factors: spatial, temporal, qualitative, quantitative, geographical and source of occurrence. But one thing is constant - he is stable, capable of self-regulation and self-healing.

There is only one “but” if a person does not intervene. Need examples? Please. Agrarian and urban biocenosis. They are created artificially by man, based only on his needs. To successfully grow selected and unusual plant species, the soil is subjected to mechanical treatment, fertilizers and pesticides are applied, and artificial irrigation is used. If these activities cease to be carried out, then it will not be able to exist independently and will die.

Watch the video: BIOCENOSIS AS A COMMUNITY OF LIVING ORGANISMS.

STRUCTURE OF BIOCENOSIS

What are biocenoses

Groups of co-living and mutually related organisms are calledbiocenoses. The adaptability of members of a biocenosis to living together is expressed in a certain similarity of requirements for the most important abiotic environmental conditions and natural relationships with each other.

The term “biocenosis” is more often used in relation to the population of territorial areas that are distinguished on land by relatively homogeneous vegetation (usually along the boundaries of plant associations), for example, the biocenosis of spruce-sorrel forest, the biocenosis of upland meadow, white moss pine forest, the biocenosis of feather grass steppe, wheat field, etc. ). This refers to the entire set of living beings - plants, animals, microorganisms, adapted to living together in a given territory. In the aquatic environment, biocenoses are distinguished that correspond to the ecological divisions of parts of reservoirs, for example, biocenoses of coastal pebble, sandy or silty soils, and abyssal depths.

STRUCTURE OF BIOCENOSIS

1.Species structure of the biocenosis.

Under species structure biocenosis understand the diversity of species in it and the ratio of their numbers or mass. There are species-poor and species-rich biocenoses. In polar arctic deserts and northern tundras with extreme heat deficiency, in waterless hot deserts, in reservoirs heavily polluted by sewage, wherever one or several environmental factors deviate far from the average optimal level for life, communities are greatly impoverished, since only few species can adapt to such extreme conditions. Wherever abiotic conditions approach the average optimum for life, extremely species-rich communities emerge. Examples of these include tropical forests, coral reefs with their diverse populations, river valleys in arid dry regions, etc.

The species composition of biocenoses, in addition, depends on the duration of their existence. Young, just emerging communities usually include a smaller set of species than long-established, mature ones. Biocenoses created by humans (fields, vegetable gardens, orchards) are also poorer in species than similar natural systems (forest, steppe, meadow. However, even the most impoverished biocenoses include at least several dozen species of organisms belonging to different systematic and ecological groups.

In some conditions, biocenoses are formed in which there are no plants (for example, in caves or reservoirs below the photic zone), and in exceptional cases, consisting only of microorganisms (in an anaerobic environment, at the bottom of a reservoir, in rotting sludge). Species-rich natural communities include thousands and even tens of thousands of species, united by a complex system of relationships.

The influence of a variety of conditions on the diversity of species is manifested, for example, in the so-called "borderline", or edge , effect. It is well known that on the edges the vegetation is usually lush and richer, more species of birds nest, more species of insects, spiders, etc. are found than in the depths of the forest. The conditions of illumination, humidity, and temperature are more varied here. The stronger the differences between two neighboring biotypes, the more heterogeneous the conditions at their boundaries and the stronger the border effect. Species richness increases greatly in places of contact between forest herbaceous, aquatic and land communities, etc.

The species that predominate in numbers are dominants communities. For example, in our spruce forests, spruce dominates among the trees, wood sorrel and other species dominate in the grass cover, wood oxalis and other species dominate in the bird population, kinglets, robin, and chiffchaffs dominate among the mouse-like rodents, bank voles and red-gray voles, etc. However, not all dominant species equally influence the biocenosis. Among them, those stand out that, through their vital activity, to the greatest extent create the environment for the entire community and without which, therefore, the existence of most other species is impossible. Such species are called edifiers. The main edificators of terrestrial biocenoses are certain types of plants: in spruce forests - spruce, in pine forests - pine, in the steppes - turf grasses (feather grass, fescue, etc.). In some cases, animals can also be edificators. For example, in territories occupied by marmot colonies, it is their digging activity that mainly determines the nature of the landscape, microclimate, and plant growth conditions.

In addition to a relatively small number of dominant species, biocenoses include many small and rare forms. They create its species richness, increase the diversity of biocenotic connections and serve as a reserve for the replenishment and replacement of dominants, i.e. give the biocenosis stability and ensure the reliability of its functioning in different conditions. The greater the reserve of such minor species in a community, the greater the likelihood that among them there will be those that can play the role of dominants in the event of any changes in the environment.

The more specific the environmental conditions, the poorer the species composition of the community and the higher the number of individual species. In the richest biocenoses, almost all species are small in number.

The diversity of a biocenosis is closely related to its stability: the higher the species diversity, the more stable the biocenosis . Human activity greatly reduces diversity in natural communities.

2. Spatial structure .

The spatial structure of the biocenosis is determined first
in total, the composition of its plant part - phytocenosis, the distribution of above-ground and underground plant masses. Phytocenosis often acquires a clear longline addition : The assimilating above-ground plant organs and their underground parts are arranged in several layers, using and changing the environment in different ways. Layering is especially noticeable in temperate forests. For example, in spruce forests the tree, herb-shrub and moss layers are clearly distinguished. 5-6 tiers can be distinguished in a broad-leaved forest: the first, or upper, tier is formed by trees of the first size (pedunculate oak, cordate linden, sycamore maple, smooth elm, etc.); the second - trees of the second size (common mountain ash, wild apple and pear trees, bird cherry, goat willow, etc.); the third tier is the undergrowth formed by shrubs (common hazel, brittle buckthorn, forest honeysuckle, European euonymus, etc.); the fourth consists of tall grasses (borets, spreading boron, forest chist, etc.); the fifth tier is made up of lower herbs (common sedge, hairy sedge, perennial grass, etc.); in the sixth tier - the lowest grasses, such as European hoofed grass.

In forests there are always inter-tiered (extra-tiered) plants - these are algae and lichens on the trunks and branches of trees, higher spore and flowering epiphytes, lianas, etc. Layering allows plants to more fully use the light flux: shade-tolerant, even shade-loving, plants can exist under the canopy of tall plants , intercepting even weak sunlight. Vegetation layers can be of different lengths: the tree layer, for example, is several meters thick, and the grass cover is only a few centimeters thick. Each tier participates in the creation of phytoclimate in its own way and is adapted to a certain set of conditions.

The underground layering of phytocenoses is associated with different rooting depths of the plants included in their composition, with the placement of the active part of the root systems. In forests you can often observe several (up to six) underground tiers.

Animals are also predominantly confined to one or another layer of vegetation. Some of them do not leave the corresponding tier at all. For example, among insects the following groups are distinguished: soil inhabitants - geobius , ground, surface layer - herpetobium , , moss layer - bryobium, grass stand - phyllobium, higher tiers - aerobium.

Dissection in the horizontal direction is mosaic. Mosaic due to a number of reasons: heterogeneity of microrelief, soils, environment-forming influence of plants and their environmental features. It can arise as a result of animal activity (formation of soil emissions and their subsequent overgrowing, formation of anthills, trampling and eating of grass by ungulates, etc.) or humans (selective felling, fire pits, etc.), due to tree fallouts during hurricanes, etc. Changes in the environment under the influence of the vital activity of individual plant species create the so-called phytogenic mosaic.

3. Ecological structure of the biocenosis.

Different types of biocenoses are characterized by a certain ratio of ecological groups of organisms, which expresses the ecological stricture of the community. Biocenoses with similar ecological structures may have different species composition, since in them the same ecological niches can be occupied by species that are similar in ecology, but are far from related. Such types that perform the same , functions in similar biocenoses are called vicarious. For example, bison in the prairies of North America, antelopes in the savannas of Africa, wild horses and kulans in the steppes of Asia share the same ecological niche. The ecological structure of biocenoses that develop in certain climatic and landscape conditions is strictly natural. For example, in biocenoses of different natural zones the ratio of phytophages and saprophages naturally changes. In steppe, semi-desert and desert areas, animal phytophages predominate over saprophages; in forest communities of the temperate zone, on the contrary, saprophagy is more developed. The main type of feeding of animals in the depths of the ocean is predation , whereas in the illuminated, surface zone of the pelagic there are many filter feeders that consume phytoplankton or species with a mixed feeding pattern.

The ecological structure of communities is also reflected by the ratio of such groups of organisms as hygrophytes, mesophytes and xerophytes among plants or hygrophiles, mesophylls and xerophytes among animals. It is quite natural that in dry arid conditions the vegetation is characterized by a predominance of sclerophytes and succulents, while in highly moist biotopes hygro- and even hydrophytes are more abundant.

The relationship of organisms in the biocenosisX.

The basis for the emergence and existence of biocenoses is the relationship of organisms, their connections into which they enter into each other, inhabiting the same biotope. These connections determine the basic living conditions of species in a community, the possibilities of obtaining food and conquering new space.

1.Trophic connections occur when one species feeds on another ­ gim-either living individuals, or their dead remains, or waste products. Dragonflies that catch other insects in flight, dung beetles that feed on the droppings of large ungulates, and bees that collect plant nectar enter into a direct trophic relationship with species that provide food. In the case of competition between two species over food objects, an indirect trophic relationship arises between them, since the activity of one affects the food supply of the other. Any effect of one species on the eatability of another or the availability of food for it should be regarded as an indirect trophic relationship between them. For example, caterpillars of nun butterflies, eating pine needles, make it easier for bark beetles to gain access to weakened trees.

Topical and trophic connections are of greatest importance in a biocenosis and form the basis of its existence. It is these types of relationships that keep organisms of different species close to each other, uniting them into fairly stable communities of different scales.

3. Phoric connections. This is the participation of one species in the spread of another. Animals act as transporters. The transfer of seeds, spores, and plant pollen by animals is called zoochory; the transfer of other smaller animals is called zoochory. phoresia. Animals can capture plant seeds in two ways: passive and active. Passive capture occurs when an animal's body accidentally comes into contact with a plant, the seeds or infructescences of which have special hooks, hooks, and outgrowths (straw, burdock). The active method of capture is eating fruits and berries. Animals excrete seeds that cannot be digested along with their droppings. Animal phoresia is common mainly among small arthropods, especially in various groups of mites. It is one of the methods of passive dispersal and is characteristic of species for which transfer from one biotope to another is vital for preservation or prosperity. Dung beetles sometimes crawl with raised elytra, which they are unable to fold due to mites densely littering their bodies. Among large animals, phoresia is almost never found.

4. Factory connections . This is a type of biocenotic relationship into which a species enters, using excretory products, either dead remains, or even living individuals of another species for its constructions (fabrication). So birds use tree branches, mammal fur, grass, leaves, down and feathers of other bird species, etc. to build nests. The megachila bee places eggs and supplies in cups constructed from the soft leaves of various shrubs (rose hips, lilac, acacia, etc.).