The concept of an ecological niche and its features. Ecological niche

Environmental niche is a place of type in nature, mainly in biocenosis, including both its position in space and the functional role in the community, attitude to abiotic conditions of existence (Khrustalev, Matishov, 1996). It is important to emphasize that this niche is not just a physical space occupied by the body, but also its place in the same assessplace, determined by its environmental functions. Yu. Odum (1975) figuratively presented an ecological niche as an occupation, the "profession" of the body in the system of species to which he belongs, and its habitat is the "address" of the species.

Knowledge of the ecological niche allows you to answer questions, how, where and what the appearance eating, whose prey it is, how and where he rests and breeds (Dazho, 1975).

The model of an ecological niche proposed by G. E. Hutchinson is quite simple: sufficiently at orthogonal projections to postpone the intensity values \u200b\u200bof various factors, and from the points of the tolerance limits to restore perpendicular, then the space limited by them and will correspond to the ecological niche of this species. Environmental niche is the area of \u200b\u200bcombinations of such values \u200b\u200bof environmental factors, within which this species May exist indefinitely for a long time.

For example, for the existence of a terrestrial plant, a fairly specific combination of temperature and humidity, and in this case can we talk about a two-dimensional niche. For the marine animal, it is already necessary in addition to at least two factors - salinity and oxygen concentration - then it is already necessary to talk about a three-dimensional niche, and so on. In fact, these factors are many and niche multidimensional.

The environmental niche, determined only by the physiological characteristics of the organisms, is called fundamental, and that, within which the species actually occurs in nature - implemented.

The realized niche is the part of the fundamental niche, which this type, population in the state "to defend" in a competitive struggle. Competition, according to Yu. Odumu (1975, 1986), is the negative interactions of two organisms seeking to the same (Table 4.1). Interwide competition is any interaction between populations that harmful affects their growth and survival. Competition is manifested in the form of combating species for environmental niches.

The classification of biotic interactions of populations of two species is given in Table. 4.1.

interaction			The overall nature of interaction
1. Neutralism			No population affects another
2. Competition, direct interaction			Direct mutual suppression of both species
3. Competition, interaction due to resources			Indirect suppression with an external resource deficiency
4. Amenzalism			Population 2 suppresses a population 1, but he does not have a negative impact
6. Predation			Predator's individuals 1 is usually larger than the individuals of the victim 2
7. Commminasalism			Population 1, commented, benefits from the association; population 2 this combination is indifferent
I- promccope			Interaction favorably for both species but not necessarily
^. Mutualism			Interaction favorably for both species and necessarily

Table 4.1 "O" means that the population does not have any influence in the interaction of species; "+" - that it benefits from the interaction of species; "-" - that it is experiencing a negative impact of such interaction.

There is no two different speciesHaving occupy the same environmental niche, but there are nearby species, often so similar that they need, essentially, the same niche. In this case, when the niches partially overlap, there is a particularly rigid competition, but ultimately a niche occupies one species. The phenomenon of environmental disagreement of closely related (or similarly) species received the name of the principle of competitive exception, or the principle of Gause, in honor of the scientist who has proved its existence experimentally in 1934

Neutralism is such a form of biotic relationships, when the cohabitation of two species in one territory does not entail nor positive nor negative consequences for them. In this case, views are not related directly to each other and do not even contact each other. For example, proteins and moose, monkeys and elephants, etc. The relationship of neutralism is characteristic of the rich species of communities.

Amenzalism is biotic relationships in which the growth of the growth of one type (Amenaxala) products of the allocation of the other occurs. Such relations are usually attributed to direct competition and called antibiosis. They are most well studied in plants that apply various poisonous substances in the fight against competitors for resources, and this phenomenon is called alleopathy.

Amenzalism is very common in aquatic environment. For example, blue-green algae, causing water bloom, thereby poisoning the aqueous fauna, and sometimes even the cattle that comes on the water. Similar "abilities" show other algae. They highlight peptides, quinone, antibiotics and other substances that are poisonous even in small doses. They call these poisons by ecconnetes.

Predators are called animals that feed on other animals, which they catch and kill. For predators, a hunting behavior is characteristic. Insect abundance, their small sizes and easily accessibility turn the activity of carnivorous predators, usually birds, in a simple "gathering"

mining, just as the seeds collect, "bird grains, pi-buried by them. Insectivore predators in the method of mastery of food are approaching her herbivores. Some birds can be powered by insects and seeds.

So, the most rigid competition is manifested when the contact between populations has been established recently, for example, due to changes in the ecosystem under the influence of human activity. That is why the ill-conceived human intervention in the biocenosis structure often leads to epidemic flashes.

Any living organism is adapted (adapted) to certain environmental conditions. Changing its parameters, their output for some borders suppresses the life of organisms and can cause their death. The requirements of this or that organism to environmental factors of the medium are caused by the area (the borders of the distribution) of the kind to which the body belongs, and within the range - specific habitats.

Havory - Spatially bounded set of conditions of medium (abiotic and biotic), providing the whole cycle of development and reproduction of individuals (or group of individuals) of one species. This, for example, hedge, pond, grove, rocky shore, etc. At the same time, within the limits of habitat, places with special conditions may be allocated (for example, under the crust of the trunk of the tree in the grove), in some cases is called microelectrics.

For the aggregate characteristics of the physical space occupied by the organisms of the form, their functional role in the biotic habitat, including the method of nutrition (trophic status), lifestyle and relationship with other species, American scientist J. Greennell in 1928. The term "ecological niche" is introduced. Its current definition is such.

Environmental niche is a totality

· All organism requirements for habitat conditions (composition and modes environmental factors) and the place where these requirements are satisfied;

· Total sets of biological characteristics and physical parameters of the medium that determine the conditions for the existence of a particular type, the transformation of energy to them, the exchange of information with the environment and themselves like.

Thus, the ecological niche characterizes the degree of biological specialization of the species. It can be argued that the habitat of the body is his "address", while the ecological niche is his "occupation", or "lifestyle", or "profession". For example, the habitat of the thrush includes forests, parks, meadows, gardens, gardens and yards. Its ecological niche includes factors such as nesting and hatching of chicks on trees, insect food, earthworms and fruits, transfer of fruit-berry seeds with their excrement.

Environmental specificity of species is emphasized axom of environmental adaptation: Each type is adapted to a strictly defined, specific set of existence conditions - ecological niche.

Since the types of organisms are environmentally friendly, they have specific environmental niches.

Thus, as in the land of the types of living organisms - as many ecological niches.

Organisms leading a similar lifestyle, as a rule, do not live in the same places due to interspecific competition. According to established in 1934. Soviet biologist G. F. Gauz (1910-1986) the principle of competitive mutual exclusion: Two types do not occupy the same ecological niche.

In nature also acts the rule is obligatory to fill ecological niches: The empty ecological niche is always completed.

Folk wisdom formulated these two postulates as follows: "Two bear can not get along in one burgher" and "Nature does not tolerate emptiness."

These systemic observations are implemented in the formation of biotic communities and biocenoses. Environmental niches are always filled, although this sometimes requires considerable time. The encountered expression "Free Ecological Niche" means that in a certain place is weak competition for any kind of feed and there is an insufficiently used amount of other conditions for a certain type in similar natural systems, but not in those considered.

It is especially important to take into account natural patterns when trying to intervene in the existing (or undergoing in a certain place) the situation in order to create more favorable conditions For a person. Thus, the following are proved by biologists: in cities, with increasing pollution of the territory, the number of raven is increasing. When you try to improve the situation, for example, by means of their physical destruction, the population may encounter the fact that the ecological niche in the urban environment liberated by the corners will be quickly occupied by the view having a close ecological niche, namely, rats. Such a result can hardly be recognized as a victory.

Each biological species plays a role in its ecosystem. Ecologically proved that some species called key species, radically affect many other organisms in the ecosystem. The disappearance of the key type from the ecosystem can provoke a whole cascade of sharp drops of population numbers and even extinct those species that depended on it in one form or another.

An example of a key species can be considered an earthy turtle. Earthy turtle lives on sandy hills in Florida and other southern United States. It is slow, the size of a dining plate, the animal pulls out a hole with a depth of 9 meters. In the hot, non-sensuous ecosystems of the south of the USA, such holes become asylums from heat for nearly 40 other species of animals, such as gray fox, opossum, snake indigo and many insects. In those places where the earthen turtle was exterminated or brought to the verge of extincting with numerous hunters for its exquisite meat, many tests that depend on the turtle ceased to exist.

Environmental niches of all living organisms are divided into specialized and general. This division depends on the main sources of nutrition of the respective species, sizes of habitat, sensitivity to abiotic environmental factors.

Specialized niches. Most of the types of plants and animals are adapted to existence only in the narrow range of climatic conditions and other environmental characteristics, feed on a limited set of plants or animals. Such species have a specialized niche, defining their habitat in the natural environment.

So, a gigantic panda has a narrowly specialized niche, for 99% is powered by leaves and bamboo shoots. Mass destruction of certain types of bamboo in the areas of China, where Panda dwells, led this animal to extinction.

A variety of species and forms of plant and animal world, existing in wet tropical forests, is associated with the presence of a number of specialized ecological niches in each of the well-pronounced forest vegetation tiers. Therefore, the intensive cutting of these forests caused the extinction of millions of specialized species of plants and animals.

Common niches. Types with shared niches are characterized by light adaptability to changes in environmental habitat factors. They can successfully exist in a variety of places, feed on various foods and withstand sharp fluctuations in natural conditions. Common ecological niches are available in flies, cockroaches, mice, rats, people, etc.

For species having common environmental niches, there is a significantly less threat of extinction than those with specialized niches.

While the ecosystem has sufficient number General resources, different types consume them together. However, if two or more species in one ecosystem will begin to consume one and the same scarce resource, they will be in relationships interspecific competition.

The species gets an advantage in interspecific competition if it is characteristic

More intense reproduction;

Adaptation to a wider range of temperature, illumination, water salinity or

concentration of certain harmful substances;

Depriving a competitor to access to the resource.

Methods for reducing interspecific competition:

Relocation to another area;

Transition to more hard-to-reach or difficult to digest food;

Change of time and location of feed.

The most characteristic form of interaction of species in food chains and networks is the predation, in which a particular individual of one species (predator) is powered by organisms (or parts of organisms) of another species (victim), and the predator lives separately from the victim. These two types of organisms are involved in relationship type predator - victim.

Types of stories use a number of protective mechanisms so as not to become easy prey for predators:

The ability to run quickly or fly;

Possession of thick skin or shell;

Possession of protective color or way to change color;

The ability to highlight chemicals with a smell or taste that scare up a predator or even poisoning it.

Predators also have several ways to prey the victim:

The ability to quickly run (for example, a cheetah);

Hunting flocks (for example, spotted hyenas, lions, wolves);

Calves as victims of predominantly ill, wounded and other defective individuals;

The fourth way to ensure itself with animal food is the way for which a man has gone reasonable, the way of the invention of the guns of hunting and traps, as well as animal domestication.

It often happens that two different types of organisms directly interact in such a way that they bring mutual benefits to each other. Such mutually beneficial interspace interactions are called mutualism. For example, flowers and insect pollinators.

Commminasalism is characterized by the fact that one of two types will benefit from interspecific interaction, whereas on the other it practically does not affect (neither positively nor negatively). For example, whales in the Chinese jaws.

The concept of the so-called saturated and unsaturated biocenosis is closely connected with the concept of ecological niches. The first are ecosystems in which life resources at each stage of biomass and energy transformation are used most fully. When life resources are disposed of partly, biocenoses can be called unsaturated. They are characterized by the presence of free ecological niches. However, it is extremely conditional, since environmental niches cannot exist in themselves, regardless of their species.

Unused reserves, unrealized possibilities of intensifying the flow of substances and energy are available in virtually any biogeocenosis (otherwise they could not be carried out in time and space!), All biocenoses can be considered unsaturated. The smaller the saturation of the biocenosis is, the easier it is introduced into its composition and new species are acclimatized.

Very important property of biogeocenoses, as biological systems, is their self-regulation - the ability to withstand high loads of adverse external influences, the ability to return to the conditionally initial state after significant violations of their structure (the principle of leschatel). But above a certain threshold impact mechanisms of self-healing are not triggered, and biogeocenosis is irreversibly destroyed.

During the evolutionary process, the global ecological niche of the biosphere expanded. When any kind was exhausting the genetically determined potential for the development of an ecological niche, where he was born, he either pushed out other species, conquering their environmental niches, or reassigned a lifeless niche, rebuilding under it genetically, possibly generating at the same time the new kind organisms.

At some stage of the development of the biosphere, there was a reason for a reasonable person, whose representatives are all humanity, despite all the variety of races, peoples, peoples, tribes.

The potential for the development of adult individuals of each biological species For all the qualities of individuals is genetically due to, although it may not be revealed, not filled with real content if the conditions of habitat do not have it. In relation to the population, genetic conditionality and the potential of its development are subordinate to probabilistic predestinations reflected in the statistical laws of the accomplished. This fully applies to a person - the biological species carrying the largest absolute and relative volume (compared to other types of living organisms of the Earth's biosphere) of extrelectically determined behavioral information that ensures the greatest flexibility of behavior in a rapidly changing environment.



1. General provisions. Live creatures - both plants and animals are numerous and diverse. There is no doubt that this diversity and the number of organisms are determined by the factors of habitat. Thus, each species occupies a strictly reserved place in geographical space with a specific set of physical and chemical parameters. However, the position of the form depends not only on the abiotic environmental factors, but also on the bonds of a given organism with other organisms both within its own species and representatives of other species. The wolf will not dwell on those geographic spaces, even if the set of abiotic factors is quite acceptable if there is no food resource for it. Consequently, the place that takes a view in a specific habitat must be due not only to the territory, but also related to the need for food and the reproduction function. Each of the species, as well as a particular organism, in the community (biocenosis) has its own time of stay and its place, which distinguish it from other species.

Thus, we meet with various concepts. First, it is arealspecies - the spread of the species in the geographical space (geographical aspect of the form), secondly, having habitat(habitat or biotope) - type of geographical space for a set of physical and chemical parameters and (or) biotic characteristics, where the view is inhabited and, thirdly, ecological niche, implying something more than just a place where this species dwells. The view in various parts of the range can occupy a number of different habitats.

The best and most comparative determination of the ecological niche and the medium were given by the French environmentalists R. Vibert and K. Lagler: wednesday- this is the address for which this body lives, while niche Additionally indicates the order of his classes in this place, his profession.

Some environmentalists more eagerly use the term "habitat", which is almost synonymous with the "habitat", and both concepts often overlap each other, but we will remember that the "habitat" means only the space where the view is common. In such an understanding, the term is very close to the concept of the form of the species.

2. Havory. This is a plot of sushi or a water branch engaged in a population of one species or its part and possessing it all required conditions (climate, relief, soil, nutrients). Having a view is a combination of its environmental requirements within the species range. Thus, habitat is nothing but only a component of an ecological niche. By latitude of the use of habitats distinguish stenotopic and eurritopic Organisms, i.e. Organisms occupying specific spaces with a certain set of environmental factors, and organisms that exist in a wide range of environmental factors (cosmopolitans). If we are talking about the habitat of the community of organisms or about the place of biocenosis, the term "biotop" is used more often. Having habitat has another synonym ecotop. - Geographical space, characterized by a specific set of environmental parameters. In this case, the population of any kind, inhabiting in this space, is called ecotype.

The term "habitat" can be applied both to specific organisms and communities in general. We can point me the meadow as a single habitat of various herbs and animals, albeit herbs, and animals occupy different ecological niches. But never this term should be replaced by the concept of "ecological niche".

Havings may designate a complex of interconnected some living and non-living characteristics of geographic space. For example, habitats of aquatic insects Claop-Gladysh and Float is a shallow water-covered sections of the lakes. These insects occupy one habitat, but have different trophic chains (glades are an active predator, and the platest feeds on decomposing vegetation), which is distinguished by the ecological niches of these two species.

Havitage can be denoted and only a biotic environment. So bacillus and bacteria live within other organisms. The lice live in the score of the owner. Some mushrooms are associated with a specific type of forest (boomes). But habitat can be represented by a purely physico-geographical environment. You can specify the tidal and tidy shore of the sea, where such a variety of organisms live. It can both the desert, and a separate mountain, dunes, stream and river, lake, etc.

3. Ecological niche - Concept, according to Yu. Oduma, more capacious. Environmental niche, as the English scientist showed C. Elton (1927), includes not only the physical space occupied by the body, but also the functional role of the body in the community. Elton distinguished the niche as a position of the species depending on other types of community. Presentation of C. Elton that Niche does not have synonym for habitat received widespread recognition and distribution. The body is very important its trophic position, lifestyle, connection with other organisms, etc. and its position relative to the gradients of external factors as the conditions of existence (temperature, humidity, pH, composition and type of soil, etc.).

These three aspects of an ecological niche (space, functional role of the body, external factors) are convenient sound Spatial niche (niche places), trophic niche (functional niche), in understanding Ch. Elton, and multidimensional niche (the entire volume and set of biotic and abiotic characteristics is taken into account, hyperoballing). The ecological niche of the body depends not only on where it lives, but also includes the total amount of its requirements for environment. The body not only has the effect of environmental factors, but also makes its demands on them.

4. Modern Environmental Niche Concept formed on the basis of the model proposed J. Khatchinson (1957). According to this model, the ecological niche is part of the imaginary multidimensional space (hyperoblum), the individual dimensions of which correspond to the factors necessary for the normal existence and reproduction of the body. Niche Hutchinson, which we will be called multidimensional (hyperpricted), can be described using quantitative characteristics and operate with it using mathematical calculations and models. R. Whitteker (1980) determines the environmental niche as the position of the type in the community, implying that the community is already associated with a scooping biotope, i.e. With a certain set of physical and chemical parameters. Consequently, the ecological niche is the term used to designate the specialization of the population of the species within the community. Group of types in biocenosis, which have similar functions and niches of the same size, are called guilds. Species that occupy the same niches in different geographic areas are called environmental equivalents.

5. Individuality and uniqueness of environmental niches. Whatever close to the place of habitat would be organisms (or species as a whole), no matter how close their functional characteristics in biocenoses, they will never occupy the same ecological niche. Thus, the number of environmental niches on our planet is endless. It is imperative that you can imagine a human population, all the individuals of which only possess its unique niche. It is impossible to present two absolutely identical people with absolutely identical morphophysiological and functional characteristics, including such as mental, attitude towards themselves, the absolute need for the type and quality of food, sexual relations, behavior rate, etc. But individual niches of various people can overlap on individual environmental parameters. For example, students can be interconnected by one university, specific teachers and at the same time may differ in behavior in society, in choosing food, biological activity, etc.

6. Measuring ecological niches. For the characteristics of the niche usually use two standard measurements - niche widthand overlapping niche with neighboring niches.

Under the width of the niche is understood as gradients or the range of action of any environmental factor, but only within the limits of this hyperspace. The width of the niche can be determined by the lighting intensity, along the length of the trophic chain, in the intensity of the action of any abiotic factor. Under the overlap of ecological niches, the overlap of the width of niches is also implied, and the overlap of hyperoblos.

7. Types of ecological niches. Two main types of environmental niches are distinguished. First, it is fundamental (formal) niche - the greatest "abstract The populated hyperoballion, "where the effect of environmental factors without the influence of competition provides the maximum abundance and functioning of the species. However, the view is experiencing constant changes in environmental factors within its range. In addition, as we already know, the increase in the action of one factor can change the relation of the species to another factor (a consequence of the Libiha law), and its range may change. The action of two factors simultaneously can change the relationship of the species to each of them specifically. Always within ecological niches are biotic limitations (predation, competition). All these actions lead to the fact that the actual look occupies an ecological space, which is much smaller than the hyperspace of the fundamental niche. In this case, we are talking about implemented niche, i.e. real niche.

8 . Principle Vandermer and Gause. J.H.Vandermer (1972) significantly expanded the concept of Hutchinson's niche realized. He came to the conclusion that if n interacting species coexisted in this particular habitat, they will take absolutely different environmental niche implemented, the number of which will be N. This observation got a name principle of Vandermer.

Competitive interaction can concern both spaces, biogenic elements, the use of light (trees in the forest) and the process of struggle for the female, for food, as well as depending on the predator, exposure to diseases, etc. Usually the most rigid competition is observed at the interspecific level. It can lead to replacement of one type of a population of another species, but can lead to equilibrium between two species (usually such nature equilibrium is set in the predator-victim system). Extreme cases are an outstanding one species outside of this habitat. There are cases when one species displaces another in the trophic chain and makes it go to the use of other food. Observation of the behavior of nearby organisms with a similar way of life and similar morphology shows that such organisms are trying to never dare in the same place. This observation was done Joseph Greenellein 1917-1928, the lives of California birds studied. Actually Grinell introduced the concept "niche", But did not contribute to this concept of differences between niche and habitat.

If close-friendly organisms live the water and the same place, then they or will use different food resources, or lead an active lifestyle in different time (night Day). Such an environmental separation of nearby species got a name principle of competitive exception or principle Gause by the name of the Russian biologist, experimentally showed the effect of this principle in 1932. In his conclusions, Gause used the concept of Elton about the position of the species in the community depending on other species.

9. Space niche. Environmental niches of species are something more than the ratio of a species to some one gradient of the medium. Very many signs or axis of multidimensional space (hyperoballing) are very complex for measurement or cannot be expressed by linear vectors (for example, behavior, addiction, etc.). Therefore, it is necessary, as R.Uittereer (1980) said rightly, move from the concept of the niche axis (recall the width of the niche according to any one or several parameters) to the concept of its multidimensional determination, which will determine the nature of the species relationships in their full range of adaptive relationships .

If niche has a "place" or "position" of the species in the community according to the concept of Elton, then it is entitled to give it some measurements. According to Hutchinson Niche can be determined by a certain number of environment variable conditions within the community to which the types must be adapted. These variables include both biological indicators (for example, food size) and nebiological (climatic, orographic, hydrographic, etc.). These variables can serve as the axes for which the multidimensional space is reconstructed, which is called environmental spaceor Niche space. Each of the types can adapt or be resistant to a certain range of values \u200b\u200bof each variable. The upper and lower limits of all these variables are outlined by the ecological space that is capable of occupying the view. This is a fundamental niche in the sense of Hutchinson. In a simplified form, it can be imagined as a "N-Foreign Box" with the parties corresponding to the limit of the sustainability of the view on the axes of the niche.

By using a multidimensional approach to the space of the community niche, we can figure out the position of species in space, the nature of the reaction of the effect on the impact of more than one variable, the relative dimensions of the niche.

Ecological niche - A combination of all environmental factors, within which the existence of a species in nature is possible. Concept ecological niche It is usually used in the study of the relationship of environmentally friendly species relating to one trophic level. The term "ecological niche" is proposed by J. Greenlell (1917) to characterize the spatial distribution of species (i.e. ecological niche was defined as a concept close to havory).

Later, C. Elton (1927) identified an environmental niche as a position in the community, emphasizing the particular importance of trophic ties. Back in the late 19th - early 20th centuries, many researchers have noticed that two species, environmentally friendly and occupying a similar position in the community, cannot sustainably coexist on one territory. This empirical generalization has found confirmation in a mathematical model of competition of two types for one food (V. Volterra) and experimental works. Gause ( principle Gause).

Modern concept ecological niche Formed on the basis of a model of an ecological niche proposed by J. Hutchinson (1957, 1965). According to this model, an ecological niche can be represented as part of the imaginary multidimensional space (hyperoblization), the individual dimensions of which correspond to the factors necessary for the normal existence of the species.

The discrepancy between ecological niches different species By divergence, it takes mostly due to the deritment of different habitats, various food and different time of use of the same habitat. Methods of estimating the width of the ecological niche and the degree of overlapping of ecological niches of various types have been developed. LIT-RA: Giller P. Community Structure and Environmental Niche. - M.: 1988 (on BES, 1995).

In environmental modeling concept ecological niche It characterizes a certain part of the space (abstract) environmental factors, a hyperobility in which none of the environmental factors go beyond the tolerance of this species (population). Many of these combinations of values \u200b\u200bof environmental factors, in which theoretically, the existence of the form (population) is called fundamental ecological niche.

Imported ecological niche They call part of the fundamental niche, only those combinations of factors values \u200b\u200bunder which a sustainable or prosperous existence of a species (population) is possible. Concepts sustainable or prosperous The existence requires the introduction of additional formal limitations during modeling (for example, mortality should not exceed the birth rate).

If, with this combination of values \u200b\u200bof environmental factors, the plant can survive, but it is not possible to multiply, it is hardly possible to talk about well-being or stability. Consequently, such a combination of environmental factors belongs to the fundamental ecological niche, but not to the environmental niche realized.

Out of the framework of mathematical modeling, of course, there is no such rigor and clarity in determining concepts. In modern environmental literature, you can distinguish four main aspects in the submission of an ecological niche:

1) spatial niche, including a complex of favorable environmental conditions. For example, the insectivinal birds of the Ylannik-Cean-bird live, feed and nest in various forest tiers, which largely allows them to avoid competition;

2) trophic niche. It is highlighted especially due to the vastity of food as an environmental factor. The separation of food niches in the organisms of one trophic level living together, allows not only to avoid competition, but also contributes to the more complete use of food resources and, therefore, increases the intensity of the biological cycle of the substance.

For example, the noisy population of "bird bazaars" creates the impression of a complete absence of any order. In fact, each type of birds occupies a trophic niche defined by his biological characteristics: some feed on the shore, others - at a considerable distance, alone catch fish at the surface, others - at a depth, etc.

Trophic and spatial niches of various species can be partially overlapping (remember: the principle of environmental duplication). Niche can be wide (non-specialized) and narrow (specialized).

3) multidimensional niche, or niche as a hyperob. The idea of \u200b\u200bthe multidimensional ecological niche is associated with mathematical modeling. All many combinations of the values \u200b\u200bof environmental factors are considered as a multidimensional space. In this, a huge variety, we are interested only in such combinations of the values \u200b\u200bof environmental factors in which the existence of the body is possible - this hyperobility and corresponds to the concept of a multidimensional ecological niche.

4) functional An idea of \u200b\u200becological niche. This presentation complements the previous ones and is based on the functional similarity of a variety of environmental systems. For example, they speak the ecological niche of herbivore animals, or small predators, or animals that feed on plankton, or normal animals, etc. The functional idea of \u200b\u200becological niche emphasizes role Organisms in the ecosystem and corresponds to the usual concept of "profession" or even "position in society". It is in a functional plan that they talk about ecological equivalents - species that occupy functionally similar niches in various geographic regions.

"The habitat of the body is a place where he lives, or a place where it can usually find it. Ecological niche - The concept is more capacious, including not only the physical space occupied by the type (population), but also the functional role of this species in the community (for example, its trophic position) and its position relative to the gradients of external factors - temperature, humidity, pH, soil and other conditions of existence. These three aspects of the ecological niche are conveniently denoted as a spatial niche, a trophic niche and a multidimensional niche, or a niche as a hyperoball. Consequently, the ecological niche of the body depends not only on where he lives, but also includes the total amount of its environmental requirements.

Species that occupy the same niches in different geographic areas are called environmental equivalents"(Yu. Odum, 1986).

V.D. Fedors and T.G. Guilmans (1980, p. 118 - 127) celebrate:

"The study of the realized niches by describing the behavior of the function of well-being in the cross section of their direct and planes corresponding to some elected environmental factors is widely used in ecology (Fig. 5.1). At the same time, depending on the nature of the factors that the considered considered private function Well-being, you can distinguish the "climatic" niches, "trophic", "affic", "hydrahemical" and other, so-called private niches.

A positive conclusion from the analysis of private niches can serve as a conclusion from the opposite: if the projections of private niches on some (the more some) do not intersect from the axes, the niches themselves in the space of greater dimension do not intersect. ...

Logically three options are possible. mutual location niches of two species in the space of environmental factors: 1) separation (complete discrepancy); 2) partial intersection (overlapping); 3) Complete inclusion of one niche to another. ...

Nish's separation is a fairly trivial case, reflecting the fact of the existence of species adapted to various environmental conditions. Cases of partial intersection of niches are much more interest. As mentioned above, overlapping projections Even in several coordinates immediately, strictly speaking, does not guarantee the actual overlap of the multidimensional niche. Nevertheless, practical work The presence of such intersections and data on the occurrence of species in close conditions is often considered sufficient arguments in favor of overlapping the niche species.

For the quantitative measurement of the degree of bumps of the niches of two species, it is natural to use the value of the ratio of the intersection of sets ... to the volume of their association. ... In some special cases, the calculation of the measure of the intersection of NIS projections is of interest. "

Educational tests to the topic 5

The position of the species that it occupies in the general bioscenosis system, the complex of its biosotic ties and the requirements for abiotic factors of the medium is called ecological niche species.

The concept of an ecological niche turned out to be very fruitful for understanding the laws of the joint life of species. Many environmentalists worked on its development: J. Greennell, Ch. Elton, Khatchinson, Yu. Odum, etc.

The concept of "ecological niche" should be distinguished from the concept of "habitat". In the latter case, the part of the space that is populated with the view and which has the necessary abiotic conditions for its existence. The ecological niche of the form depends not only on the abiotic conditions of the medium, but also at least from its biotocetic environment. The nature of the occupied ecological niche is defined both by the environmental capabilities of the species and the fact that these possibilities can be implemented in specific biocenosis. This is the characteristic of the lifestyle, which the species can lead in this community.

G. Khatchinson put forward the concepts of a fundamental and implemented ecological niche. Under fundamental it is understood as the entire set of conditions under which the view can successfully exist and multiply. In natural biocenoses, however, species are far away from all the resources suitable for them due to, above all, competitive relations. Implemented ecological niche - This is the position of the species in a particular community, where it limits complex bioceneotic relations. In other words, the fundamental environmental niche characterizes the potential possibilities of the species, and the realized part of them, which can be realized in these conditions, with this accessibility of the resource. Thus, the implemented niche is always less than fundamental.

Ecology is widely discussed by the question of how many environmental niches can accommodate biocenosis and how many species of any particular group having close requirements for the environment can get along together.

Specialization of the type of nutrition, the use of space, activity time and other conditions is characterized as a narrowing of its ecological niche, reverse processes - as its expansion. Communities have great influence on the expansion or narrowing of the environmental niche of the community. Competitive exception rule,formulated G. F. Gause for similar types of species, can be expressed in such a way that two types do not get along in one ecological niche.

Experiments and observations in nature show that in all cases where species cannot avoid competition for the main resources, weaker competitors are gradually displaced from the community. However, in biocenoses there are many possibilities of at least partial distinction of ecological niches of similar types of species.

The way out of competition is achieved due to the discrepancy between the requirements for the medium, a change in lifestyle, which, in other words, is the distinction between environmental niche species. In this case, they acquire the ability to coexist in one biocenosis. Each of those living together in the absence of a competitor is capable of a more complete use of resources. This phenomenon is easy to observe in nature. So, herbate plants Elniki is able to be content with a small amount of soil nitrogen, which remains from the interception of its roots of trees. However, if you cut the roots of these firings on a limited area, the conditions of nitrogen food are improving and they will grow into growth rapidly, taking a dense green color. Improving the living conditions and an increase in the number of any species as a result of the removal from the biocenosis of another, close to environmental requirements, is called competitive release.

The separation of jointly living ecological niches with partial overlapping is one of the mechanisms of stability of natural biocenoses. If any of the species sharply reduces its number or falls out of the community, its role is taken by others. The more species in the biocenosis, the lower the number of each of them, the stronger their environmental specialization is expressed.In this case, they are talking about "more dense packaging of ecological niches in biocenosis."

In close-friendly species living together, very subtle distinctions of ecological niches are usually observed. So, grazing in African savannahs in different ways use pasture food: zebras are cut into the main top of herbs, the antopes of the GNU feed the fact that they leave them zebras, choosing certain types of plants, the gazelles pluck the lowest herbs, and the topic antiflands are satisfied with high dry Stems left after other herbivores. The same "division of labor" in the South European Steppes was once carried out by wild horses, crops and horses (Fig. 92).

Fig. 92. Different types of herbivores eat grass at different heights in African savannas (top rows) and in the steppes of Eurasia (lower rows) (according to F. Fuente, 1972; B. D. Abaturov, G. V. Kuznetsov, 1973)

In our winter forests Insectivore birds, rustling in trees, also avoid competition with each other due to the different search nature. For example, crawls and food are harvested on the trunks. At the same time, rapidly examine the tree rapidly, quickly grabbing insects falling on the eyes or seeds, which turned out to be in large cracks of the bark, while small foods are thoroughly shaking the slightest shutters on the surface of the trunk, in which their thin-shaped beak penetrates. In winter, in mixed pieces, big sits lead a wide search on the trees, in the bushes, on the stump, and often in the snow; Tits-Gaughters examine predominantly large branches; Long-tailed tits are looking for food at the ends of the branches; Small kols carefully shake up the tops of coniferous crowns.

Ants exist in natural conditions of multi-shaped associations, whose members differ in the lifestyle. In the forests of the Moscow region, such an association of species is most often found: the dominant appearance (Formica Rufa, F. Aquilonia or Lasius Fuliginosus) takes several tiers, L. flavus is active in the soil, in the litter of the forest - Myrmica Rubra, a formal tier is mastered by L. Niger and F. Fusca, trees - Camponotus Herculeanus. Specialization in life in different tiers is reflected in the vitality of species. In addition to separation in space, the ants differ in the nature of the production of food, the time of daily activity.

In the deserts, the most developed complex ants, collecting food on the surface of the soil (herpetobionts).Among them are distinguished representatives of three trophic groups: 1) day zoconfagographs - active in the hottest time, feed on insect corpses and active in the day of small alive insects; 2) night zoophages - hunt for later insects with soft seals, which appear on the surface only at night, and on muddy arthropods; 3) Carpophages (day and night) - eat plant seeds.

Together they can dwell along several types of one trophic group. The mechanisms of exit from competition and disarming of environmental niche are the following.

1. Dimensional differentiation (Fig. 93). For example, the average weights of the working individuals of the three most common in the sands of the duct-age zooncrophages in the sands are as 1: 8: 120. Approximately the same balance of scales in a solid cat, a lynx and a tiger.

Fig. 93. Comparative dimensions of four types of ants from a group of day zoconphographs in the sandy desert of central doodles and the distribution of production of three types by weight classes (in M. Dlussky, 1981): 1 - medium and large workers CataGlyphis Setipes; 2 - C. Pallida; 3 - Acantholepis Semenovi; 4 - Plagiolepis Pallescens

2. Behavioral differences enclosed in different foraging strategies. Ants that create roads and use the mobilization of porters for transfer to the nest of detected foods, feed mainly by the seeds of plants forming the curtains. The ants whose foragers work as single collectors are collected mainly seeds of plants distributed dispersed.

3. Spatial differentiation. Within one tier, the collection of food with different types can be timed to different areas, for example, in open places or under the bushes of wormwood, on sand or clay venues, etc.

4. Differences in activity time it is predominantly by the time of day, but some species have noted incurredness of activity and seasons of the year (mostly spring or autumn activity).

Environmental niches of species of variability in space and in time. They can be sharply delimited in individual development, depending on the stage of ontogenesis, as, for example, caterpillars and imago scrapers, larvae and beetles of the May Khrushch, tadpoles and adult frogs. In this case, the habitat is also changing, and all biocenotic surroundings. In other species, environmental niches occupied by young and adult forms are closer, but nevertheless there are always differences between them. So, adult perchs and their fry, living in the same lake, use different energy sources for their existence and are included in different power chains. Flocks live at the expense of small plankton, adults - typical predators.

The weakening of interspecific competition leads to the expansion of the ecological niche of the species. On the oceanic islands with poor fauna, a series of birds in comparison with their relatives in the continent settles more varied habitats and expands the spectrum of feed, since it does not face with competing species. The island inhabitants have even increased variability of the beak shape as an indicator of the expansion of the nature of feed ties.

If interspecific competition narrows the ecological niche of the species, not allowing to manifest themselves to all its potencies, then intraspecific competition, on the contrary, contributes to the expansion of environmental niches. With the increased size of the species, the use of additional feed, the development of new habitats, the emergence of new biocenotic connections.

In the water bodies of the plant, fully immersed in water (Elday, Rogolitnik, Uuhut) are in other conditions of temperature, illumination, gas regime than floating on the surface (television relazes, waterfronts, ores) or roofing on the bottom and endowing the leaves on the surface (water lily, Kubashka, Victoria). They differ and interrelations with the environment. The epiphytes of tropical forests occupy similar, but nevertheless are not identical niches, as they belong to different environmental groups in relation to light and water (helophids and scyophytes, hygrofitis, mesophytes and xerophytes). Different epiphytic orchids have highly specialized pollinators.

In a ripe wide forest, the trees of the first tier - oak ordinary, elm smooth, maple plain-shaped, linden carcaseholder, ash's ash have similar life forms. The wood canopy formed by their crowns turns out to be in the same horizon, in similar environments. But attentive analysis shows that they participate in different ways in the life of the community and, therefore, occupy different environmental niches. These trees differ in the degree of lightness and shadowability, flowering and fruiting timing, ways to pollinate and spread fruit, consorts and so on. Oak, Elm and ash - anemophilic plants, but the saturation of the medium of their pollen occurs in different times. Maple and Lipa - entomophiles, good turbines, but bloom at different times. Oak - Zoohoria, in the rest of the decide trees - anemokhory. The composition of the consorts is all different.

If the crown of the crown of trees is in the same horizon, then the active root endings are located at different depths. Oak roots penetrate the most deeply, above are the roots of maple and even more superficially - ash. OPEDs of different types of trees is disposed of with different speed. The leaves of linden, maple, elm, the ash of the spring is almost completely decomposed, and the leaves of oak and the spring are still forming a loose forest litter.

In accordance with the representations of L. G. Ramensky on the environmental individuality of species and taking into account the fact that plant species in the community participate in different ways in the development and transformation of the medium and transformation of energy, it can be considered that in the prevailing phytocenoses, each type of plant has its own ecological niche .

In the ontogenesis of plants, like many animals, change the environmental niche. With age, they are more intensely used and convert medium. Plant transition to the generative period significantly expands the circle of consorts, changes the size and tension of the phytogenic field. The media-forming role of aging, sedenie plants decreases. They lose many consorts, but the role of destructors associated with them increases. Production processes are weakened.

Plants have overlap of ecological niches. It is enhanced in certain periods when limiting the resources of the medium, but since species use resources individually, selectively and with different intensity, competition in sustainable phytocenoses is weakened.

Fig. 94. Correlation between a variety of deciduous tiers and species diversity of birds (Channon indices on Macaruta from E. Pianka, 1981)

Bibliography

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Khristoforova N.K. Basics of ecology. Vladivostok: Dalnaka, 1999.

Gilyarov A. M. Population Ecology. M.: Publishing House of Moscow State University, 1990.