ecological niche- the place of the species in nature, mainly in the biocenosis, including both its position in space and its functional role in the community, its relation to the abiotic conditions of existence (Khrustalev, Matishov, 1996). It is important to emphasize that this niche is not just the physical space occupied by the organism, but also its place in society, determined by its ecological functions. Y. Odum (1975) figuratively presented an ecological niche as an occupation, a “profession” of an organism in the system of species to which it belongs, and its habitat is the “address” of the species.

Knowledge of the ecological niche allows one to answer the questions of how, where and what a species feeds on, whose prey it is, how and where it rests and breeds (Dajo, 1975).

The ecological niche model proposed by G. E. Hutchinson is quite simple: it is enough to plot the intensity values ​​on orthogonal projections various factors, and restore perpendiculars from the points of tolerance limits, then the space limited by them will correspond to the ecological niche of this species. An ecological niche is an area of ​​combinations of such values ​​of environmental factors within which this species can exist indefinitely.

For example, for existence ground plant a certain combination of temperature and humidity is enough, and in this case we can talk about a two-dimensional niche. For a marine animal, in addition to temperature, at least two more factors are needed - salinity and oxygen concentration - then we should already talk about a three-dimensional niche, etc. In fact, there are many of these factors and the niche is multidimensional.

The ecological niche, determined only by the physiological characteristics of organisms, is called fundamental, and the one within which the species actually occurs in nature is called realized.

A realized niche is that part of the fundamental niche that a given species, population is able to "defend" in competition. Competition, according to Y. Odum (1975, 1986), - negative interactions two organisms striving for the same thing (Table 4.1). Interspecific competition is any interaction between populations that adversely affects their growth and survival. Competition manifests itself in the form of the struggle of species for ecological niches.

The classification of biotic interactions between populations of the two species is given in Table 1. 4.1.

interactions			General nature of interaction
1. Neutralism			Neither population affects the other
2. Competition, direct interaction			Direct mutual suppression of both types
3. Competition, interaction due to resources			Indirect suppression with a shortage of an external resource
4. Amensalism			Population 2 suppresses population 1, but is itself not adversely affected.
6 Predation			Predator 1 individuals are usually larger than prey 2 individuals
7. Commensalism			Population 1, the commensal, benefits from pooling; population 2 this union is indifferent
I- Industrial cooperation			The interaction is favorable for both species, but not necessarily
^. Mutualism			The interaction is favorable for both species and is mandatory

In Table 4.1, "O" means that the population is not affected by the species interaction; "+" - that she benefits from the interaction of species; "-" - what she experiences bad influence such an interaction.

There are no two various kinds, occupying the same ecological niches, but there are closely related species, often so similar that they require essentially the same niche. In this case, when the niches partially overlap, there is especially fierce competition, but in the end the niche is occupied by one species. The phenomenon of ecological separation of closely related (or otherwise similar) species was called the principle of competitive exclusion, or the Gause principle, in honor of the scientist who proved its existence experimentally in 1934.

Neutralism is a form of biotic relationship when the cohabitation of two species in the same territory does not entail either positive or negative consequences for them. In this case, the species are not directly related to each other and do not even contact each other. For example, squirrels and elks, monkeys and elephants, etc. Neutralism relationships are characteristic of species-rich communities.

Amensalism is a biotic relationship in which the growth of one species (amensal) is inhibited by the excretory products of another. Such relationships are usually referred to as direct competition and are called antibiosis. They are best studied in plants that use various toxic substances in the fight against competitors for resources, and this phenomenon is called allelopathy.

Amensalism is very common in aquatic environment. For example, blue-green algae, causing water blooms, thereby poison the aquatic fauna, and sometimes even livestock that comes to drink. Other algae show similar "abilities". They secrete peptides, quinone, antibiotics and other substances that are poisonous even in small doses. These poisons are called ectocrine substances.

Predators are called animals that feed on other animals, which they catch and kill. Predators are characterized by hunting behavior. The abundance of insects, their small size and easy availability turn the activity of carnivorous predators, usually birds, into a simple "gathering"

prey, just as they collect seeds, “bird grains that feed on them. Insectivorous predators, in a way that has mastered food, approach the grazing of herbivores. Some birds can eat both insects and seeds.

So, the toughest competition appears when the contact between populations is established recently, for example, due to changes that have occurred in the ecosystem under the influence of human activity. That is why ill-conceived human intervention in the structure of the biocenosis often leads to epidemic outbreaks.

1. General provisions. Living beings, both plants and animals, are many and varied. There is no doubt that this diversity and abundance of organisms is determined by environmental factors. Thus, each species occupies a strictly assigned place in the geographic space with a specific set of physical and chemical parameters. However, the position of a species depends not only on abiotic environmental factors, but also on the connections of a given organism with other organisms, both within its own species and with representatives of other species. The wolf will not live in those geographic areas, even if the set of abiotic factors is quite acceptable for him, if there is no food resource for him here. Therefore, the place that a species occupies in a particular habitat must be determined not only by the territory, but also be associated with the need for food and the function of reproduction. Each of the species, as well as a specific organism, in a community (biocenosis) has its own own time stay and its place, which distinguish it from other species.

Thus we meet different concepts. First, this range species - the distribution of the species in geographic space (the geographical aspect of the species), secondly, species habitat(habitat or biotope) is the type of geographic space in terms of a set of physical and chemical parameters and (or) biotic characteristics where the species lives and, thirdly, ecological niche, implying something more than just the place where this species lives. A species can occupy a number of different habitats in different parts of its range.

The best and most accurate comparative definition of the ecological niche and environment was given by the French ecologists R. Wiebert and C. Lagler: Wednesday is the address where he lives given organism, whereas niche additionally indicates the type of his occupation in this place, his profession.

Some ecologists are more willing to use the term "habitat," which is almost synonymous with "habitat," and the two terms often overlap, but remember that "habitat" refers only to the space in which a species occurs. In this sense, this term is very close to the concept of the range of a species.

2. habitat. This is a piece of land or a body of water occupied by a population of one species or part of it and possessing for its existence all necessary conditions(climate, topography, soil, nutrients). The habitat of a species is a set of sites that meet its ecological requirements within the species range. Thus, a habitat is nothing but a component of an ecological niche. According to the breadth of the use of habitats, they distinguish stenotopic and eurytopic organisms, i.e. organisms that occupy specific spaces with a particular set of environmental factors, and organisms that exist in wide range environmental factors (cosmopolites). If we are talking about the habitat of a community of organisms or the place of a biocenosis, then the term "biotope" is more often used. Location has another synonym ecotope– geographical space characterized by a specific set of environmental parameters. In this case, the population of any species living on given space, called ecotype.

The term "habitat" can be applied both to specific organisms and to communities as a whole. We can point to a meadow as a single habitat for various herbs and animals, although both herbs and animals occupy different ecological niches. But this term should never replace the concept of "ecological niche".

Habitat can refer to a complex of interconnected some living and non-living characteristics of a geographic space. For example, the habitat of aquatic insects of the smooth bug and the float is shallow areas of lakes covered with vegetation. These insects occupy the same habitat, but have different trophic chains (smooth is an active predator, while float eats decaying vegetation), which distinguishes the ecological niches of these two species.

The location can designate and only biotic environment. This is how bacilli and bacteria live inside other organisms. Lice live in the hairline of the host. Some mushrooms are associated with a particular type of forest (boletus). But the habitat can also be represented by a purely physical-geographical environment. You can point to the tidal coast of the sea, where such a variety of organisms live. It can be a desert, and a separate mountain, dunes, a stream and a river, a lake, etc.

3. ecological niche concept, according to Y. Oduma, more capacious. Ecological niche, as shown by an English scientist C. Elton(1927), includes not only the physical space occupied by an organism, but also functional role organisms in the community. Elton distinguished niches as the position of a species in relation to other species in a community. Ch. Elton's idea that a niche is not a synonym for a habitat has received wide recognition and distribution. The trophic position, way of life, connections with other organisms, etc. are very important for the organism. and its position relative to the gradients external factors as conditions of existence (temperature, humidity, pH, composition and type of soil, etc.).

These three aspects of the ecological niche (space, the functional role of the organism, external factors) can be conveniently referred to as spatial niche(niche place) trophic niche(functional niche), in the understanding of Ch. Elton, and multidimensional niche(the whole volume and set of biotic and abiotic characteristics are taken into account, hypervolume). The ecological niche of an organism depends not only on where it lives, but also includes total amount its requirements for the environment. The body not only experiences the action of environmental factors, but also makes its own demands on them.

4. Modern concept ecological niche formed on the basis of the model proposed J. Hutchinson(1957). According to this model, an ecological niche is a part of an imaginary multidimensional space (hypervolume), individual dimensions of which correspond to the factors necessary for the normal existence and reproduction of an organism. Hutchinson's niche, which we will call multidimensional (hyperspace), can be described using quantitative characteristics and operated with it using mathematical calculations and models. R. Whittaker(1980) defines an ecological niche as the position of a species in a community, implying that the community is already associated with a specific biotope, i.e. with a certain set of physical and chemical parameters. Therefore, an ecological niche is a term used to denote the specialization of a population of a species within a community. Groups of species in a biocenosis with similar functions and niches of the same size are called guilds. Species occupying the same niche in different geographical areas, are called environmental equivalents.

5. Individuality and originality of ecological niches. No matter how close in habitat organisms (or species in general) are, no matter how close their functional characteristics in biocenoses are, they will never occupy the same ecological niche. Thus, the number of ecological niches on our planet is uncountable. Figuratively, one can imagine human population, all individuals of which have only their own unique niche. It is impossible to imagine two absolutely identical people with absolutely identical morphophysiological and functional characteristics, including such as mental, attitude towards their own kind, an absolute need for the type and quality of food, sexual relations, norms of behavior, etc. But individual niches various people may overlap on individual environmental parameters. For example, students can be linked by one university, specific teachers, and at the same time, they can differ in their behavior in society, in the choice of food, biological activity, etc.

6. Measuring ecological niches. To characterize a niche, two are usually used. standard measurements – niche width and niche overlap with neighboring niches.

Niche width refers to gradients or the range of some environmental factor, but only within a given hyperspace. The width of a niche can be determined by the intensity of illumination, by the length of the trophic chain, by the intensity of the action of some abiotic factor. The overlapping of ecological niches means overlapping along the width of niches and overlapping of hypervolumes.

7. Types of ecological niches. There are two main types of ecological niches. First, this fundamental(formal) niche - the largest "abstract inhabited hypervolume”, where the action of environmental factors without the influence of competition ensures the maximum abundance and functioning of the species. However, the species experiences constant changes in environmental factors within its range. In addition, as we already know, an increase in the action of one factor can change the relation of a species to another factor (a consequence of Liebig's law), and its range can change. The action of two factors at the same time can change the attitude of the species to each of them specifically. There are always biotic restrictions (predation, competition) within ecological niches. All these actions lead to the fact that in reality the species occupies an ecological space that is much smaller than the hyperspace of the fundamental niche. In this case, we are talking about realized niche, i.e. real niche.

8 . Principle VanderMeer and Gause. J.H. Vandermeer (1972) greatly expanded the concept of Hutchinson's realized niche. He came to the conclusion that if N interacting species coexist in a given particular habitat, then they will occupy completely different realized ecological niches, the number of which will be equal to N. This observation is called the Vandermeer principle.

Competitive interaction can concern both space, nutrients, the use of light (trees in the forest), and the process of fighting for a female, for food, as well as dependence on a predator, susceptibility to disease, etc. Usually, the toughest competition is observed at the interspecific level. It can lead to the replacement of a population of one species by a population of another species, but it can also lead to an equilibrium between two species (usually this the balance of nature is established in the predator-prey system). Extreme cases are the displacement of one species by another outside the given habitat. There are times when one species displaces another in food chain and forces him to switch to the use of other foods. Observation of the behavior of closely related organisms with a similar way of life and similar morphology shows that such organisms try never to live in the same place. This observation was made Joseph Grinell in 1917-1928, who studied the life of California mockingbirds. Grinell actually introduced the concept "niche", but did not introduce into this concept the distinction between niche and habitat.

If closely related organisms live in the same water and in the same place, then they will either use different food resources or lead an active lifestyle in different time(night Day). This ecological separation of closely related species is called principle of competitive exclusion or Gause principle named after the Russian biologist who experimentally demonstrated the operation of this principle in 1932. In his conclusions, Gause used Elton's concept of the position of a species in a community depending on other species.

9. niche space. The ecological niches of species are more than the relation of a species to a single environmental gradient. Many signs or axes of multidimensional space (hypervolume) are very difficult to measure or cannot be expressed by linear vectors (for example, behavior, addiction, etc.). Therefore, it is necessary, as rightly noted by R. Whittaker (1980), to move from the concept of the niche axis (remember the width of the niche in terms of one or more parameters) to the concept of its multidimensional definition, which will reveal the nature of species relationships with their full range of adaptive relationships .

If a niche is a "place" or "position" of a species in a community according to Elton's concept, then it is right to give it some measurements. According to Hutchinson, a niche can be defined by some number variable conditions the environments within the community to which the species must be adapted. These variables include both biological indicators (for example, food size) and non-biological ones (climatic, orographic, hydrographic, etc.). These variables can serve as axes along which the multidimensional space, which is called ecological space or niche space. Each of the species can adapt or be resistant to some range of values ​​of each variable. The upper and lower limits of all these variables delineate the ecological space that a species can occupy. This is the fundamental niche in Hutchinson's understanding. In a simplified form, this can be imagined as an "n-sided box" with sides corresponding to the stability limits of the view on the axes of the niche.

By applying a multidimensional approach to community niche space, we can find out the position of species in space, the nature of the response of a species to the impact of more than one variable, relative sizes niches

Synecology studies the relationship between individuals of populations of various species and their adaptability to conditions. external environment. Ecologists have established that the organisms that make up living communities are tied to certain spatial coordinates in which they interact with each other and with parts of the biosphere: water, soil, atmosphere.

This place in biogeocenoses has a name - an ecological niche. The examples considered in our article are intended to prove that it is inherent in every biological species and is a consequence of the interaction of the organism with other individuals and environmental factors.

Ecological characteristics of the species

All, without exception, in the process of phylogenesis adapt to specific abiotic factors. They limit the habitat of the population. How a community of organisms interacts with habitats and with other populations constitutes its ecological characteristic, whose name is an ecological niche. animal examples, life cycle which occurs in different spatial and trophic areas of the biogeocenosis are dragonflies belonging to the type Arthropods, class Insects. Adults - adults, being active predators, have mastered air shell, while their larvae - naiads, breathing with gills, are hydrobionts.

Characteristics of the ecological niche of species

The author of the classic work "Fundamentals of Ecology" Y. Odum proposed the term "ecological niche", which he uses to study the biotic relationships of a population at all levels of its organization. According to the scientist, the position of an individual in wildlife, that is, its vital status is an ecological niche. An example illustrating this definition, - a community of plants called pioneers. They have special physiological and vegetative properties that allow them to easily conquer free territories. These include creeping couch grass, They form primary biocenoses, which change over time. Odum called the place of the organism in nature its address, and the way of life - a profession.

Model J. Hutchinson

Let us turn again to the definition of the term "ecological niche". An example illustrating it is the white-tailed deer, whose life cycle is associated with the sub-canopy space - thickets of perennial shrubs. They serve the animal not only as a source of nutrition, but also as protection. The hypervolume model of a biogeocenosis area created by Hutchinson is a cell of life support for an individual of a population. Organisms can live in it long time avoiding the external environment. The researches of the scientist, carried out by him on the basis of the created mathematical model, give insight into optimal boundaries the existence of communities of living organisms in ecosystems.

Gause principle

It is also called the competitive exclusion rule and is used to describe two forms of the struggle for existence - intraspecific and interspecific, studied back in the 19th century by Charles Darwin. If populations have overlapping needs, for example, trophic (that is, a common food supply) or spatial (overlapping habitats - ranges), on which their numbers depend, then the time of coexistence of such communities is limited. It's in end result will lead to the expulsion (crowding out of a less adapted population) and the resettlement of more adapted and rapidly reproducing organisms of another species.

For example, individuals of the species gradually replaced black rat populations. They are currently few in number and live near water bodies. Three parameters characterize the concept of "ecological niche". An example explaining this statement was considered by us earlier, namely: the gray rat species settled everywhere (spatial distribution), it is omnivorous (food ration) and hunts both day and night (separation of activity in time).

Another example that characterizes the rule of competitive exclusion: the first settlers who came to Australia brought populations of European bees with them. In connection with the development of beekeeping, the number of these insects increased sharply, and they gradually replaced the native Australian bee from the areas of its permanent habitat, which put this species on the brink of extinction.

A similar case occurred with the populations of the domestic rabbit, introduced by the same discoverers of the continents. Plenty of food, excellent climatic conditions and the lack of competition led to the fact that individuals of this species began to capture the habitats of other populations and multiplied in such numbers that they began to destroy crops.

The place of a biological species in an ecosystem

Let's continue answering the question of what an ecological niche is. An example that gives the most complete answer is the life status of a red clover plant. Its distribution area is Europe, North Africa, middle Asia. Populations grow optimally in sufficiently moist meadows, at temperatures of +12...+21 °C. They form perennial herbs or forest litter and are producers in the food chains of biogeocenosis.

Ecological Niche Doctrine

Optimal and real space for the existence of a population

Recall that the totality of connections of organisms with individuals of other populations and with environmental conditions is an ecological niche. An example of soil saprotrophic bacteria that feed on dead organic matter and purify the earth, as well as improve its agrochemical properties, confirms the formation of a large number of biotic bonds with other soil inhabitants: insect larvae, plant roots, fungi. The vital activity of soil bacteria directly depends on the temperature and moisture content of the soil, its physical and chemical composition.

Other inhabitants - nitrifying chemotrophic bacteria - form stable with plant populations of the legume family: alfalfa, common vetch, lupine. All of the above parameters, both biotic and environmental conditions, make up the realized ecological niche of bacteria. It is part of a potential (fundamental niche) biogeocenosis, which is a complex of optimal conditions in which a species could exist indefinitely.

Rules for the mandatory filling of a multidimensional area of ​​the ecosystem

If the biogeocenosis has undergone a sharp impact of extreme abiotic phenomena, for example, fires, floods, earthquakes or negative human activity, some of its areas become free, that is, deprived of plant and animal populations that previously lived here. The emergence of new life forms - succession - leads to a change in that part of the biogeocenosis, the name of which is the ecological niche of plants. Examples of its settlement after a fire indicate that the broad-leaved forest is being replaced by one-biennial herbaceous plants with high vegetative energy: fireweed, willow-herb, coltsfoot and others, that is, the vacated part of the space is immediately populated by populations of new species.

In this article, we have studied in detail such a concept as the ecological niche of the body. The examples considered by us confirm that it is a multidimensional complex adapted for optimal living conditions for plant and animal populations.

Every organism during its existence is influenced by various conditions environment. These can be factors of animate or inanimate nature. Under their influence, through adaptation, each species takes its place - its ecological niche.

general characteristics

The general characteristic of a cell occupied by an animal or plant consists of the definition and description of its model.

An ecological niche is a place occupied by a species or individual organism in the biocenosis. It is determined taking into account the complex of biocenotic relationships, abiotic and biotic factors of the environment. There are many interpretations of this term. According to the definitions of various scientists, the ecological niche was also called spatial or trophic. This is because, settling in his cell, the individual occupies the territory he needs and creates his own food chains.

J. E. Hudchence's model of hypervolume dominates today. It is a cube, on its axes there are environmental factors that have their own range (valency). The scientist divided niches into 2 groups:

• Fundamentals are those that create optimal conditions and equipped necessary resources to keep the population alive.
• Implemented. They have a number of properties that are due to competing species.

Characteristics of ecological niches

The characteristics of ecological niches include three main components:

• Behavioral characteristic is a way of responding of a species to stimuli. And also how he gets food, the features of his shelter from enemies, adaptability to abiotic factors (for example, the ability to withstand cold or heat).
• Spatial characteristic. These are the location coordinates of the population. For example, penguins live in Antarctica, New Zealand, South America.
• Temporary. It describes the activity of species in certain period time: day, year, season.

Principle of competitive exclusion

The principle of competitive exclusion states that there are as many ecological niches as there are species of different organisms. Its author is the famous scientist Gause. He discovered patterns while working with ciliates different types. The scientist grew organisms first in a monoculture, studying their density and mode of nutrition, and later combined the species for breeding in one container. It was noticed that each species significantly reduced the number, and as a result of the struggle for food, each organism occupied its own ecological niche.

It cannot be that two different species occupy the same cell in the biocenosis. To become a winner in this competitive struggle, one of the species must have some advantage over the other, be more adapted to environmental factors, since even very similar species always have some differences.

Law of constancy

The law of constancy is based on the theory that the biomass of all organisms on the planet must remain unchanged. This statement was confirmed by V. I. Vernadsky. He - the founder of the doctrine of the biosphere and noosphere - was able to prove that with an increase or decrease in the number of organisms in one niche, it is necessarily compensated in another.

This means that an extinct species is replaced by any other that can easily and quickly adapt to environmental conditions and increase its population. Or, conversely, with a significant increase in the number of some organisms, the number of others decreases.

Mandatory rule

rule mandatory filling says that an ecological niche never remains empty. When a species goes extinct for any reason, its place is immediately taken by another. The organism that occupies the cell enters into a competitive struggle. If he turns out to be weaker, he is forced out of the territory and forced to look for another place to settle.

Ways of coexistence of organisms

Ways of coexistence of organisms can be conditionally divided into positive - those that benefit all organisms, and negative, which are beneficial only to one species. The first was called "symbiosis", the second - "mutualism".

Commensalism is a relationship in which organisms do not harm each other, but do not help either. It can be intraspecific and interspecific.

Amensalism is an interspecies mode of coexistence in which one species is oppressed by another. However, one of them does not receive required quantity nutrients, which slows down its growth and development.

Predation - Predatory species with this method of coexistence feed on the body of the victims.

Competition can be within the same species or between different ones. It appears under the condition that organisms need the same food or territory with optimal climatic conditions for them.

The evolution of human ecological niches

The evolution of human ecological niches began with the existence of archanthropes. They led a collective way of life, used only those abundances of nature that were the most accessible to them. Use animal food on the this segment existence was reduced to a minimum. To search for food, the archanthropes had to master a large number of forage area.

After man mastered the tool of labor, people began to hunt, thereby having a considerable impact on environment. As soon as a person got fire, he made the transition to the next stage of development. After the increase in population, agriculture arose - as one of the ways to adapt to the lack of food in those places where intensive hunting and gathering Natural resources were almost exhausted. In the same period, livestock raising began. This led to a settled way of life.

Then there was nomadic pastoralism. As a result of nomadic human activity great amount pastures are depleted, this forces nomads to move and develop more and more new lands.

Human ecological niche

The ecological niche of a person is changing along with changes in the way people live. From other living organisms Homo sapiens has the ability to articulate speech, abstract thinking, high level development of material and non-material culture.

Man like species was distributed in the tropics and subtropics, in places where the altitude was up to 3-3.5 km. Due to certain features that a person is endowed with, his habitat has greatly increased in size. But as far as the fundamental ecological niche is concerned, it has remained virtually unchanged. The existence of a person becomes more complicated outside the original space, he has to confront various unfavorable factors. This is possible not only through the adaptation process, but also through the invention of various defense mechanisms and devices. For example, man invented different types heating systems to combat such abiotic factors as cold.

Thus, we can conclude that the ecological niche is occupied by each organism after competition and adheres certain rules. It must have an optimal area of ​​​​the territory, suitable climatic conditions and be provided with living organisms that are included in food chain dominant type. All living beings that are within the niche necessarily interact.

ecological niche- a set of all environmental factors within which the existence of a species in nature is possible. concept ecological niche is usually used in the study of the relationship of ecologically close species belonging to the same trophic level. The term "ecological niche" was proposed by J. Grinell (1917) to characterize spatial distribution species (i.e. ecological niche was defined as a concept close to habitat).

Later, Ch. Elton (1927) defined an ecological niche as the position of a species in a community, emphasizing the particular importance of trophic relationships. Back in the late 19th and early 20th centuries, many researchers noticed that two species that are ecologically close and occupy a similar position in the community cannot coexist stably on the same territory. This empirical generalization was confirmed in the mathematical model of the competition of two species for one food (V. Volterra) and experimental work G.F. Gause ( Gause principle).

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

The divergence of ecological niches of different species through divergence occurs for the most part due to confinement to different habitats, different food and different times of using the same habitat. Methods for estimating the width of the ecological niche and the degree of overlapping of ecological niches of various species have been developed. Liter: Giller P. Community structure and ecological niche. - M .: 1988 (according to BES, 1995).

In environmental modeling, the concept ecological niche characterizes a certain part of the space (abstract) of environmental factors, a hypervolume in which none of the environmental factors goes beyond the tolerance of a given species (population). The set of such combinations of values ​​of environmental factors under which the existence of a species (population) is theoretically possible is called fundamental ecological niche.

Realized ecological niche name a part of the fundamental niche, only those combinations of factor values ​​under which a stable or prosperous existence of a species (population) is possible. Concepts sustainable or prosperous existence require the introduction of additional formal restrictions in modeling (for example, mortality should not exceed the birth rate).

If, with a given combination of values ​​of environmental factors, a plant can survive, but is not able to reproduce, then one can hardly speak of well-being or sustainability. Therefore, this combination of environmental factors refers to the fundamental ecological niche, but not to the realized ecological niche.

Outside the framework of mathematical modeling, of course, there is no such rigor and clarity in the definition of concepts. In modern environmental literature There are four main aspects in the idea of ​​an ecological niche:

1) spatial niche including a complex of favorable environmental conditions. For example, insectivorous birds of blueberry spruce live, feed and nest in different forest layers, which largely allows them to avoid competition;

2) trophic niche. It stands out especially because of the great importance of food as an environmental factor. The division of food niches in organisms of one trophic level living together, allows not only to avoid competition, but also contributes to a more complete use of food resources and, consequently, increases the intensity biological cycle substances.

For example, the noisy population of "bird markets" creates the impression total absence any order. In fact, each bird species occupies a trophic niche strictly defined by its biological characteristics: some feed near the coast, others at a considerable distance, some fish at the surface, others at depth, etc.

The trophic and spatial niches of different species may overlap (remember: the principle of ecological duplication). Niches can be broad (non-specialized) or narrow (specialized).

3) multidimensional niche, or a niche as a hypervolume. The concept of a multidimensional ecological niche is associated with mathematical modeling. The whole set of combinations of values ​​of environmental factors is considered as a multidimensional space. In that vast multitude we are only interested in such combinations of values ​​of environmental factors under which the existence of an organism is possible - this hypervolume corresponds to the concept of a multidimensional ecological niche.

4) functional idea of ​​an ecological niche. This representation complements the previous ones and is based on the functional similarity of a variety of ecological systems. For example, they talk about the ecological niche of herbivores, or small predators, or animals that feed on plankton, or burrowing animals, etc. functional representation about the ecological niche emphasizes role organisms in an ecosystem and corresponds to the usual concept of "occupation" or even "position in society". Exactly at functional plan talking about environmental equivalents– species occupying functionally similar niches in different geographic regions.

“The habitat of an organism is the place where it lives, or the place where it can usually be found. ecological niche- a more capacious concept, including not only the physical space occupied by a species (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, etc. other conditions of existence. These three aspects of the ecological niche are conveniently referred to as the spatial niche, the trophic niche, and the multidimensional niche, or the hypervolume niche. Therefore, the ecological niche of an organism depends not only on where it lives, but also includes the total amount of its environmental requirements.

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

V.D. Fedorov and T.G. Gilmanov (1980, pp. 118-127) note:

“The study of realized niches by describing the behavior of the well-being function on a section of their straight lines and planes corresponding to some selected environmental factors is widely used in ecology (Fig. 5.1). At the same time, depending on the nature of the factors to which the considered private function well-being, one can distinguish between niches "climatic", "trophic", "edaphic", "hydrochemical" and others, the so-called private niches.

A positive conclusion from the analysis of private niches can be a conclusion from the contrary: if the projections of private niches on some (especially some) of the axes do not intersect, then the niches themselves do not intersect in space higher dimension. ...

There are three logical possibilities relative position niches of two types in the space of environmental factors: 1) separation (complete mismatch); 2) partial intersection (overlapping); 3) complete inclusion of one niche into another. ...

Separation of niches is a rather trivial case, reflecting the existence of species adapted to different ecological conditions. Of much greater interest are cases of partial intersection of niches. As mentioned above, the overlapping of projections even in several coordinates at once, strictly speaking, does not guarantee the actual overlapping of the multidimensional niches themselves. However, in practical work the presence of such intersections and data on the occurrence of species in close environments is often considered sufficient arguments in favor of overlapping species niches.

For quantitative measurement degree of overlapping niches of two types, it is natural to use the value of the ratio of the volume of the intersection of sets ... to the volume of their union. ... In some special cases, it is of interest to calculate the measure of intersection of niche projections.”

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