What is an ecological niche in ecology. Ecological niche of organisms. What is interspecies fighting

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An ecological niche is a place occupied by a species in a biocenosis, including a complex of its biocenotic connections and requirements for environmental factors. The term was coined in 1914 by J. Grinnell and in 1927 by Charles Elton.
An ecological niche is the sum of factors for the existence of a given species, the main one of which is its place in the food chain.
An ecological niche can be:
fundamental - determined by the combination of conditions and resources that allow the species to maintain a viable population;
realized - the properties of which are determined by competing species.
This difference emphasizes that interspecific competition leads to a decrease in fertility and viability and that there may be a part of the fundamental ecological niche in which a species, as a result of interspecific competition, is no longer able to live and reproduce successfully.

An ecological niche cannot be empty. If a niche becomes empty as a result of the extinction of a species, it is immediately filled by another species.
The habitat usually consists of separate areas ("patches") with favorable and unfavorable conditions; these spots are often only temporarily accessible, and they appear unpredictably in both time and space.
Vacant areas or habitat “gaps” occur unpredictably in many biotopes. Fires or landslides can lead to the formation of wastelands in forests; a storm may expose an open area seashore, and voracious predators anywhere can exterminate potential victims. These vacated areas are invariably repopulated. However, the very first settlers will not necessarily be those species that are able to successfully compete with and displace other species over a long period of time. Therefore, the coexistence of transient and competitive species is possible as long as uninhabited areas appear with suitable frequency. A transient species is usually the first to colonize a vacant area, colonize it, and reproduce. A more competitive species colonizes these areas slowly, but once colonization has begun, over time it defeats the transient species and reproduces.

The study of ecological niches is of great practical importance. When introducing foreign species into the local flora and fauna, it is necessary to find out what ecological niche they occupy in their homeland, and whether they will have competitors in the places of introduction. The wide distribution of muskrats in Europe and Asia is explained precisely by the absence of rodents with a similar lifestyle in these regions.

In related species living together, there is a very fine delineation of ecological niches. Thus, ungulates grazing in African savannas use pasture food in different ways: zebras mainly pick off the tops of grasses, wildebeests feed on what zebras leave for them, gazelles pluck the lowest grasses, and topi antelopes are content with dry stems left behind by other herbivores. Due to the division of niches, the total bioproductivity of such a complex plant increases. species composition herds. A peasant herd consisting of cows, sheep, and goats uses meadows and pastures much more efficiently, from an environmental point of view, than a single-species herd; monoculture is the least effective method conducting Agriculture.
For the reproduction and long-term existence of many animal species great importance has a delineation of niches at different stages of ontogenesis: caterpillars and adults of lepidoptera, larvae and May beetles, tadpoles and adult frogs do not compete with each other, since they differ in habitat and are part of different food chains.
Interspecific competition leads to a narrowing of the ecological niche and does not allow its potential to manifest itself. Intraspecific competition, on the contrary, contributes to the expansion of the ecological niche. Due to the increase in the number of species, the use of additional food begins, the development of new habitats, and the emergence of new biocenotic connections

Content:
Introduction………………………………………………………………………. 3
1. Ecological niche……………………………………………………..... 4
1.1. The concept of an ecological niche……………………………………. 4
1.2. Width and overlap of niches……………………………………. 5
1.3. Niche differentiation……………………………………………. 8
1.4. Evolution of niches………………………………………………………10
2. Aspects of the ecological niche…………………………………………….12
3. Modern concept of ecological niche……………………….... 13
4. Individuality and uniqueness of ecological niches………... 13
5. Types of ecological niches………………………………………………… 14
6. Niche space………………………………………………………. 15
Conclusion…………………………………………………………………… 16
List of references………………………………………………………... 19

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Introduction.
This work discusses the topic “ Ecological niches" An ecological niche is the place occupied by a species (more precisely, its population) in a community, the complex of its biocenotic connections and requirements for abiotic environmental factors. This term was coined in 1927 by Charles Elton.
An ecological niche is the sum of factors for the existence of a given species, the main one of which is its place in the food chain.
The purpose of the work is to identify the essence of the concept of “ecological niche”.
The objectives of the study stem from the stated goal:
- give the concept of an ecological niche;
- analyze the features of ecological niches;
- consider the ecological niches of species in communities.
An ecological niche is the position occupied by a species in a community. The interaction of a given species (population) with partners in the community of which it is a member determines its place in the cycle of substances determined by food and competitive relationships in the biocenosis. The term “Ecological niche” was proposed by the American scientist J. Grinnell (1917). The interpretation of an ecological niche as the position of a species for the purpose of feeding one or several biocenoses was given by the English ecologist C. Elton (1927). Such an interpretation of the concept of ecological niche allows us to give a quantitative description of the ecological niche for each species or for its individual populations. To do this, compare the abundance of the species (number of individuals or biomass) with
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indicators of temperature, humidity or any other environmental factor. In this way, it is possible to identify the optimum zone and the limits of deviations tolerated by the type - the maximum and minimum of each factor or set of factors. As a rule, each species occupies a certain ecological niche, to which it is adapted throughout the course of evolutionary development. The place occupied by a species (its population) in space (spatial ecological niche) is more often called habitat.
Let's take a closer look at ecological niches.

1.Ecological niche
Any type of organism is adapted to certain conditions of existence and cannot arbitrarily change its habitat, diet, feeding time, breeding place, shelter, etc. The whole complex of relationships to such factors determines the place that nature has allocated to a given organism and the role that it must play in the general life process. All this comes together in the concept ecological niche.
1.1.The concept of an ecological niche.
An ecological niche is understood as the place of an organism in nature and the entire way of its life activity, its life status, fixed in its organization and adaptations.
At different times, different meanings were attributed to the concept of an ecological niche. At first, the word “niche” denoted the basic unit of distribution of a species within the space of an ecosystem, dictated by structural and
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instinctive limitations of this type. For example, squirrels live in trees, moose live on the ground, some bird species nest on branches, others in hollows, etc. Here the concept of ecological niche is interpreted mainly as a habitat, or spatial niche. Later, the term “niche” was given the meaning of “the functional status of an organism in a community.” This mainly concerned the place of a given species in the trophic structure of the ecosystem: type of food, time and place of feeding, who is a predator for a given organism, etc. This is now called the trophic niche. Then it was shown that a niche can be considered as a kind of hypervolume in a multidimensional space built on the basis of environmental factors. This hypervolume limited the range of factors in which a given species could exist (hyperdimensional niche).
That is, in the modern understanding of an ecological niche, at least three aspects can be distinguished: the physical space occupied by an organism in nature (habitat), its relationship to environmental factors and to neighboring living organisms (connections), as well as its functional role in the ecosystem. All these aspects are manifested through the structure of the organism, its adaptations, instincts, life cycles, life “interests”, etc. The right of an organism to choose its ecological niche is limited by a rather narrow framework assigned to it from birth. However, its descendants can claim other ecological niches if appropriate genetic changes have occurred in them.
1.2. Width and overlap of niches.
Using the concept of ecological niche, Gause's rule of competitive exclusion can be rephrased as follows: two different species cannot occupy the same ecological niche for a long time or even enter the same ecosystem; one of them must either die or
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change and occupy a new ecological niche. By the way, intraspecific competition is often greatly reduced, precisely because at different stages of the life cycle many organisms occupy different ecological niches. For example, a tadpole is a herbivore, and adult frogs living in the same pond are predators. Another example: insects in the larval and adult stages.
Can live in one territory in an ecosystem a large number of organisms of different species. These may be closely related species, but each of them must occupy its own unique ecological niche. In this case, these species do not enter into competitive relationships and, in a certain sense, become neutral to each other. However, often ecological niches different types may overlap in at least one aspect, such as habitat or diet. This leads to interspecific competition, which is usually not severe and contributes to the clear delineation of ecological niches. To characterize a niche, two standard measurements are usually used - the width of the niche and the overlap of the niche with neighboring niches.
Niche width refers to gradients or the range of action of some environmental factor, but only within a given hyperspace. The width of the niche can be determined by the intensity of lighting, the length of the trophic chain, and the intensity of the action of any abiotic factor. By overlapping ecological niches we mean both overlapping the width of niches and overlapping hypervolumes.The width of the ecological niche is a relative parameter that is assessed by comparison with the width of the ecological niche of other species. Eurybionts usually have wider ecological niches than stenobionts. However, the same ecological niche can have different widths according to different
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directions: for example, by spatial distribution, food connections, etc.
Ecological niche overlap occurs when different species use the same resources when living together. The overlap can be complete or partial, according to one or more parameters of the ecological niche.

If the ecological niches of organisms of two species are very different from each other, then these species, having the same habitat, do not compete with each other (Fig. 3).

If ecological niches partially overlap (Fig. 2), then their joint coexistence will be possible due to the presence of specific adaptations in each species.

If the ecological niche of one species includes the ecological niche of another (Fig. 1), then intense competition occurs; the dominant competitor will displace its rival to the periphery of the fitness zone.
Competition has important environmental consequences. In nature, individuals of each species are simultaneously subject to interspecific and intraspecific competition. Interspecific in its consequences
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is the opposite of intraspecific, since it narrows the area of habitats and the quantity and quality of necessary environmental resources. Intraspecific competition contributes to the territorial distribution of species, that is, the expansion of the spatial ecological niche. The end result is the ratio of interspecific and intraspecific competition. If interspecific competition is greater, then the range of a given species decreases to an area with optimal conditions and at the same time the specialization of the species increases.

1.3. Niche differentiation.
Thus, in ecosystems, a law similar to the Pauli exclusion principle in quantum physics is implemented: in a given quantum system, more than one fermion (particles with half-integer spin, such as electrons, protons, neutrons, etc.) cannot exist in the same quantum state. ). In ecosystems, there is also a quantization of ecological niches that tend to be clearly localized in relation to other ecological niches. Within a given ecological niche, that is, within the population that occupies this niche, differentiation continues into more specific ones.
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niches occupied by each specific individual, which determines the status of this individual in the life of a given population.
Does similar differentiation occur at lower levels of the system hierarchy, for example, at the level of a multicellular organism? Here we can also distinguish different “types” of cells and smaller “bodies”, the structure of which determines their functional purpose within the body. Some of them are immobile, their colonies form organs, the purpose of which makes sense only in relation to the organism as a whole. There are also mobile simple organisms that seem to live their own “personal” life, which nevertheless fully satisfies the needs of the entire multicellular organism. For example, red blood cells do only what they “can”: bind oxygen in one place , and in another place it is released. This is their “ecological niche”. The vital activity of each cell of the body is structured in such a way that, while “living for itself,” it simultaneously works for the benefit of the entire organism. Such work does not tire us at all, just as we are not tired by the process of eating, or doing what we love (if, of course, all this is in moderation). The cells are designed in such a way that they simply cannot live any other way, just as a bee cannot live without collecting nectar and pollen from flowers (probably this brings her some kind of pleasure).
Thus, all of nature “from bottom to top” seems to be permeated with the idea of differentiation, which in ecology has taken shape in the concept of an ecological niche, which in a certain sense is analogous to an organ or subsystem of a living organism. These “organs” themselves are formed under the influence of the external environment, that is, their formation is subject to the requirements of the supersystem, in our case - the biosphere.

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1.4. Evolution of niches.
It is known that under similar conditions, ecosystems similar to each other are formed, having the same set of ecological niches, even if these ecosystems are located in different geographical areas, separated by insurmountable obstacles. The most striking example in this regard is provided by the living world of Australia, which has long developed separately from the rest of the land world. In Australian ecosystems, functional niches can be identified that are equivalent to the corresponding niches of ecosystems on other continents. These niches turn out to be occupied by those biological groups that are present in the fauna and flora of a given area, but are similarly specialized for the same functions in the ecosystem that are characteristic of a given ecological niche. Such types of organisms are called ecologically equivalent. For example, the large kangaroos of Australia are equivalent to the bison and antelopes of North America (on both continents these animals are now replaced mainly by cows and sheep). Such phenomena in the theory of evolution are called parallelism. Very often parallelism is accompanied by convergence (convergence) of many morphological (from the Greek word morphe - form) characteristics. So, despite the fact that the whole world was conquered by plantar animals, in Australia, for some reason, almost all mammals are marsupials, with the exception of several species of animals brought much later than the living world of Australia finally took shape. However, there are also marsupial moles, marsupial squirrels, marsupial wolves, etc. here. All these animals are not only functionally, but also morphologically similar to the corresponding animals of our ecosystems, although there is no relationship between them. All this testifies in favor of the presence of a certain “program” for the formation of ecosystems in these specific
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conditions. All matter can act as “genes” that store this program, each particle of which hologramically stores information about the entire Universe. This information is realized in the actual world in the form of laws of nature, which contribute to the fact that various natural elements canto form into ordered structures not at all in an arbitrary manner, but in the only possible way, or at least in several possible ways. For example, a water molecule produced from one oxygen atom and two hydrogen atoms has the same spatial shape, regardless of whether the reaction took place here or in Australia, although according to Isaac Asimov’s calculations, only one chance is realized out of 60 million. Probably something similar happens in the case of the formation of ecosystems.
Thus, in any ecosystem there is a certain set of potentially possible (virtual) ecological niches strictly linked to each other, designed to ensure the integrity and sustainability of the ecosystem. This virtual structure is a kind of “biofield” of a given ecosystem, containing a “standard” of its actual (material) structure. And by and large, it doesn’t even matter what the nature of this biofield is: electromagnetic, informational, ideal or some other. The very fact of its existence is important. In any naturally formed ecosystem that has not experienced human impact, all ecological niches are filled. This is called the rule of mandatory filling of ecological niches. Its mechanism is based on the property of life to densely fill all the space available to it (in this case, space is understood as a hypervolume of environmental factors). One of the main conditions ensuring the implementation of this rule is the presence of sufficient species diversity. The number of ecological niches and their interconnection is subordinated to a single goal
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functioning of the ecosystem as a single whole, having mechanisms of homeostasis (stability), binding and release of energy and circulation of substances. In fact, the subsystems of any living organism are focused on the same goals, which once again indicates the need to revise the traditional understanding of the term “living being”. Just as a living organism cannot exist normally without one or another organ, an ecosystem cannot be sustainable if all its ecological niches are not filled.
2. Aspects of the ecological niche.

E ecological niche is a concept, according to Yu. Odum , more capacious. An ecological niche, as shown by the English scientist C. Elton (1927), includes not only the physical space occupied by an organism, but also the functional role of the organism in the community. Elton distinguished niches as the position of a species depending on other species in the community. Charles Elton's idea that a niche is not synonymous with habitat has become widely accepted and widespread. An organism is very important about its trophic position, lifestyle, connections with other organisms, etc. and its position relative to gradients of external factors as living conditions (temperature, humidity, pH, composition and type of soil, etc.).
It is convenient to designate these three aspects of the ecological niche (space, the functional role of the organism, external factors) as a spatial niche (place niche), trophic niche (functional niche), in the understanding of Ch. Elton, and a multidimensional niche (the entire volume and set of biotic and abiotic characteristics is taken into account , hypervolume). The ecological niche of an organism depends not only on where it lives, but also includes the total amount of its demands on the environment.
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The body not only experiences the effects of environmental factors, but also makes its own demands on them.

3. Modern concept of ecological niche.

It was formed on the basis of the model proposed by J. Hutchinson (1957). According to this model, an ecological niche is a part of an imaginary multidimensional space (hypervolume), the 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 (hyperdimensional), can be described using quantitative characteristics and operated with 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 species' population within a community.
Groups of species in a biocenosis that have similar functions and niches of the same size are called guilds. Species that occupy similar niches in different geographic areas are called ecological equivalents.

4. Individuality and uniqueness of ecological niches.

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

5. Types of ecological niches.

There are two main types of ecological niches. Firstly, this
fundamental (formal) niche – the largest “abstractly populated”
hypervolume" where the action environmental factors without the influence of competition, it ensures 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, increasing the action of one factor can change the relationship of a species to another factor (a consequence of Liebig's law), and its range can change. The action of two factors simultaneously can change the attitude of a species towards each of them specifically. Biotic restrictions (predation, competition) always operate within ecological niches. All these actions lead to the fact that the species actually occupies an ecological space that is much smaller than the hyperspace of the fundamental niche. In this case, we are talking about a realized niche, i.e. real niche.

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6. Niche space.

The ecological niches of species are more than the relationship of a species to any one environmental gradient. Many features 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 according to any one or several parameters) to the concept of its multidimensional definition, which will reveal the nature of the relationships of species 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 has the right to give it some measurements. According to Hutchinson, a niche can be defined by a number of environmental variables within a community to which a species must be adapted. These variables include both biological indicators (for example, food size) and non-biological indicators (climatic, orographic, hydrographic, etc.). These variables can serve as axes along which a multidimensional space is recreated, which is called ecological space or niche space. Each species can adapt or be tolerant to some range of values of each variable. The upper and lower limits of all these variables outline the ecological space that a species is capable of occupying. This is the fundamental niche in Hutchinson's understanding. In simplified form, this can be thought of as an "n-sided box" with sides corresponding to the stability limits
view on the axes of the niche. By applying a multidimensional approach to the space of a community niche, we can find out the position of species in space, the nature of the species' response to the influence of more than one variable, the relative
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niche sizes.
Conclusion.

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Bibliography:

Chernova N.M., Bylova A.M. Ecology. - M.: Education, 1988.

Brodsky A.K. Short course general ecology, Textbook for universities. - St. Petersburg: “Dean”, 2000. - 224 p.

Detailed solution to paragraph § 76 in biology for 10th grade students, authors Kamensky A.A., Kriksunov E.A., Pasechnik V.V. 2014

Gdz workbook in Biology for grade 10 you can find

1. What is a habitat?

Answer. Habitat (habitat) is a set of biotic, abiotic and anthropogenic (if any) environmental factors in any specific territory or water area, formed on the site of the primary complex of abiotic factors - ecotope. The habitat of a species or population is an important component of his/her ecological niche. In relation to terrestrial animals, the term is considered synonymous with the concepts of station (habitat of a species) and biotope (habitat of a community).

Habitats characterized by different severity of environmental factors, but having similar vegetation cover, are called biologically equivalent. Their existence is possible due to the partial compensation of factors by each other.

T. Southwood (1977) proposed classifying habitats according to the nature of changes in factors over time, highlighting the following:

unchanged - environmental conditions remain favorable indefinitely;

predictably seasonal - there is a regular change of favorable and unfavorable periods;

unpredictable - favorable and unfavorable periods have different durations;

ephemeral - with a short favorable period.

2. What is a food chain?

Answer. Food (trophic) chain - a series of species of plants, animals, fungi and microorganisms that are connected to each other by the relationship: food - consumer (a sequence of organisms in which a gradual transfer of matter and energy occurs from source to consumer).

The organisms of the subsequent link eat the organisms of the previous link, and thus a chain transfer of energy and matter occurs, which underlies the cycle of substances in nature. With each transfer from link to link, a large part (up to 80-90%) of the potential energy is lost, dissipated in the form of heat. For this reason, the number of links (types) in the food chain is limited and usually does not exceed 4-5.

3. What is interspecific struggle?

Questions after § 76

1. What is the difference between the concepts of “habitat” and “ecological niche”?

Answer. The position of a species that it occupies in the biogeocenosis, the complex of its connections with other species and requirements for abiotic environmental factors is called an ecological niche. The concept of "ecological niche" should be distinguished from the concept of "habitat". In the latter case, we are talking about the part of space where the species lives and where the necessary abiotic conditions for its existence exist. The ecological niche of a species depends not only on abiotic conditions, it characterizes the entire lifestyle that a species can lead in a given community. According to the figurative expression of ecologist Yu. Odum, a habitat is the address of a species, and an ecological niche is its “profession.” There are fundamental (or potential) and realized niches. A fundamental ecological niche is a set of optimal conditions under which a given species can exist and reproduce. Realized niche - the conditions where a species actually occurs in a given ecosystem; it always forms some part of the fundamental niche.

For the reproduction and long-term existence of many animal species, the delimitation of niches at different stages of ontogenesis is of great importance: caterpillars and adults of lepidoptera, larvae and beetles of the May beetle, tadpoles and adult frogs do not compete with each other, since they differ in habitat and are part of different food chains.

Interspecific competition leads to a narrowing of the ecological niche and does not allow its potential to manifest itself. Intraspecific competition, on the contrary, contributes to the expansion of the ecological niche. In connection with the increase in the number of the species, the use of additional food begins, the development of new habitats, and the emergence of new biocenotic connections.

2. Can different species occupy the same ecological niche?

Answer. No they can't. A large number of organisms of different species live in one habitat. For example, a mixed forest is a habitat for hundreds of species of plants and animals, but each of them has its own and only one “profession” - an ecological niche.

In the forest, elk and squirrel have similar habitats, but their niches are completely different: the squirrel lives mainly in the crowns of trees, feeds on seeds and fruits, and reproduces there. The entire life cycle of an elk is associated with the subcanopy space: feeding on green plants or their parts, reproduction and shelter in thickets.

Elements of an ecological niche:

food (types);

time and methods of nutrition;

breeding place;

place of shelter.

Ecological niches exist according to certain rules:

the wider the requirements (limits of tolerance) of a species to any or many environmental factors, the larger the space that it can occupy in nature, and therefore the wider its distribution;

if the regime of any, at least one, environmental factor in the habitat of individuals of one species has changed in such a way that its values go beyond the limits of the niche, then this means the destruction of the niche, that is, the limitation or impossibility of preserving the species in a given habitat. Other important patterns are also associated with the concept of “ecological niche” - each species has its own, unique ecological niche, i.e., as many species on Earth, so many ecological niches (2.2 million species of living organisms, of which 1.7 million species of animals). Two different species (even very close ones) cannot occupy the same ecological niche in space;

in each ecosystem there are species that claim the same niche or its elements (food, shelter). In this case, competition is inevitable, the struggle to own a niche. Such relationships are reflected by Gause's rule: if two species with similar requirements for the environment (nutrition, behavior, breeding sites) enter into a competitive relationship, then one of them must die or change its lifestyle and occupy a new ecological niche.

An ecological niche is the totality of all the requirements of a species (population) to environmental conditions (the composition and regime of environmental factors) and the place where these requirements are met.

The ecological niches of co-living species may partially overlap, but never completely coincide, because the law of competitive exclusion comes into play.

3. Can one species occupy different ecological niches? What does this depend on?

4. What is the importance of ecological niches in the life of a community?

Answer. The concept of an ecological niche is very useful for understanding the laws of coexistence of species. For example, all sorts of green plant, taking one or another part in the formation of biogeocenosis, ensures the existence of a number of ecological niches. Among them there may be niches that include organisms that feed on root tissues (root beetles) or leaf tissues (leaf beetles and sap suckers), flowers (flower beetles), fruits (fruit eaters), root secretions (eccrisotrophs), etc. Together they form an integral system of diverse uses plant mass of the body. Moreover, all heterotrophs that eat plant biomass almost do not compete with each other.

Each of these niches includes groups of organisms that are heterogeneous in species composition. For example, in environmental group Root beetles include nematodes and the larvae of some beetles (May beetles, click beetles), and the niche of plants sucking plant juices includes bugs and aphids.

Ecological niches of animals feeding on plant biomass

Groups of species in a community that have similar functions and niches of the same properties are called guilds by some authors (guild of root eaters, guild of night predators, guild of scavengers, etc.).

Consider Figure 122. Do herbivores occupy the same or different niches on the African savanna? Justify your answer. Consider Figure 123. Do the dragonfly and its larva occupy the same or different niches? Justify your answer.

Answer. In the savanna, animals occupy different ecological niches. An ecological niche is a place occupied by a species in a biocenosis, including a complex of its biocenotic connections and requirements for environmental factors. The term was coined in 1914 by J. Grinnell and in 1927 by Charles Elton.

An ecological niche is the sum of factors for the existence of a given species, the main one of which is its place in the food chain.

An ecological niche can be:

fundamental - determined by the combination of conditions and resources that allow the species to maintain a viable population;

realized - the properties of which are determined by competing species.

This difference emphasizes that interspecific competition leads to a decrease in fertility and viability and that there may be a part of the fundamental ecological niche in which a species, as a result of interspecific competition, is no longer able to live and reproduce successfully.

An ecological niche cannot be empty. If a niche becomes empty as a result of the extinction of a species, it is immediately filled by another species.

The habitat usually consists of separate areas ("patches") with favorable and unfavorable conditions; these spots are often only temporarily accessible, and they appear unpredictably in both time and space.

Vacant areas or habitat “gaps” occur unpredictably in many biotopes. Fires or landslides can lead to the formation of wastelands in forests; a storm can expose an open area of the seashore, and voracious predators anywhere can exterminate potential victims. These vacated areas are invariably repopulated. However, the very first settlers will not necessarily be those species that are able to successfully compete with and displace other species over a long period of time. Therefore, the coexistence of transient and competitive species is possible as long as uninhabited areas appear with suitable frequency. A transient species is usually the first to colonize a vacant area, colonize it, and reproduce. A more competitive species colonizes these areas slowly, but once colonization has begun, over time it defeats the transient species and reproduces.

If we compare an adult insect and dragonfly larvae, we can draw the following conclusions:

1) Larvae usually serve as the dispersal stage that ensures the spread of the species.

2) Larvae differ from adults both in the biology of nutrition, and in their habitat, and in their methods of movement (a flying dragonfly and its swimming larva), and behavioral characteristics. Thanks to this, one species can throughout the entire life cycle take advantage of the opportunities provided by two ecological niches. This increases the chances of survival of the species.

3)they can adapt to different conditions awaiting them in their second life, they have physiological endurance.

The concept of an ecological niche. In an ecosystem, any living organism is evolutionarily adapted (adapted) to certain environmental conditions, i.e. to changing abiotic and biotic factors. Changes in the values of these factors for each organism are permissible only within certain limits, within which the normal functioning of the organism is maintained, i.e. its viability. The greater the range of changes in environmental parameters a particular organism allows (normally withstands), the higher the resistance of this organism to changes in environmental factors. The requirements of a certain species to various environmental factors determine the species’ range and its place in the ecosystem, i.e. the ecological niche it occupies.

Ecological niche– a set of living conditions in an ecosystem, imposed by a species on a variety of environmental environmental factors from the point of view of its normal functioning in the ecosystem. Consequently, the concept of an ecological niche primarily includes the role or function that a given species performs in a community. Each species occupies its own, unique place in the ecosystem, which is determined by its need for food and is associated with the function of reproduction of the species.

The relationship between the concepts of niche and habitat. As shown in the previous section, a population first needs a suitable habitat, which in its abiotic (temperature, soil type, etc.) and biotic (food resources, vegetation type, etc.) factors would correspond to its needs. But the habitat of a species should not be confused with an ecological niche, i.e. the functional role of the species in a given ecosystem.

Conditions for the normal functioning of the species. The most important biotic factor for every living organism is food. It is known that the composition of food is determined primarily by the set of proteins, hydrocarbons, fats, as well as the presence of vitamins and microelements. The properties of food are determined by the content (concentration) of individual ingredients. Of course, the required properties of food differ for different types of organisms. The lack of any ingredients, as well as their excess, have a harmful effect on the vitality of the body.

The situation is similar with other biotic and abiotic factors. Therefore, we can talk about the lower and upper limits of each environmental factor, within which normal functioning of the body is possible. If the value of an environmental factor becomes below its lower limit or above its upper limit for a given species, and if this species cannot quickly adapt to the changed environmental conditions, then it is doomed to extinction and its place in the ecosystem (ecological niche) will be occupied by another species.

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Ecological niche– the totality of all environmental factors within which the existence of a species in nature is possible. Concept ecological niche usually used when studying the relationships of ecologically similar species belonging to the same trophic level. The term “ecological niche” was proposed by J. Greenell (1917) to characterize the spatial distribution of species (i.e., the ecological niche was defined as a concept close to habitat).

Later, C. Elton (1927) defined an ecological niche as the position of a species in a community, emphasizing the special importance of trophic relationships. Back in the late 19th and early 20th centuries, many researchers noticed that two species, ecologically close and occupying a similar position in the community, could not coexist stably in the same territory. This empirical generalization has been confirmed in mathematical model competition of two species for one food (V. Volterra) and experimental work of G.F. Gause ( Gause's 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 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 mostly due to their association with different habitats, different foods, and different times of use of the same habitat. Methods have been developed for assessing the width of an ecological niche and the degree of overlap of ecological niches various types. 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 limits of a given species (population). The set of such combinations of values of environmental factors at which the existence of a species (population) is theoretically possible is called fundamental ecological niche.

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

If, with a given combination of environmental factors, a plant can survive, but is not able to reproduce, then we can hardly talk about 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, four main aspects can be distinguished in the concept of an ecological niche:

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

2) trophic niche. It stands out especially because of the enormous importance of food as an environmental factor. The division of food niches among organisms of the same trophic level living together not only avoids competition, but also contributes to a more complete use of food resources and, therefore, increases the intensity of the biological cycle of matter.

For example, the noisy population of “bird markets” creates the impression of a complete absence of any order. In fact, each bird species occupies a strictly defined position. biological features trophic niche: some feed near the shore, others at a considerable distance, some fish near the surface, others at depth, etc.

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

3) multidimensional niche, or a niche as a hypervolume. The idea of a multidimensional ecological niche is associated with mathematical modeling. The entire set of combinations of environmental factor values is considered as a multidimensional space. In this huge set, 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 idea complements the previous ones and is based on the functional similarities of a wide 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. The functional concept of the ecological niche emphasizes role organisms in an ecosystem and corresponds to the usual concept of “profession” or even “position in society.” It is in functional terms that we speak of environmental equivalents– species occupying functionally similar niches in different geographical regions.

“An organism's habitat is where it lives, or where it can usually be found. Ecological niche- a more capacious concept that includes 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 gradients of external factors - temperature, humidity, pH, soil and 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 niche as hypervolume. Therefore, the ecological niche of an organism depends not only on where it lives, but also includes the total sum of its requirements for the environment.

Species that occupy similar niches in different geographic areas are called environmental equivalents"(Y. 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 at the cross section of them with straight lines and planes corresponding to some selected environmental factors is widely used in ecology (Fig. 5.1). Moreover, depending on the nature of the factors to which the particular well-being function under consideration corresponds, one can distinguish between “climatic”, “trophic”, “edaphic”, “hydrochemical” and other niches, the so-called private niches.

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

Logically there are three options 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. ...

Niche separation is a fairly trivial case, reflecting the fact of the existence of species adapted to different environmental conditions. Cases of partial overlap of niches are of much greater interest. As mentioned above, overlapping projections even along 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 similar environments is often considered sufficient evidence in favor of overlapping niches of species.

To quantitatively measure the degree of overlap between niches of two species, it is natural to use the ratio of the volume of 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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