The influence of relief on plants (dependence). Abiotic factors The influence of living organisms on the relief

The influence of the environment on the body.

Any organism is open system, which means it receives matter, energy, information from the outside and, thus, is completely dependent on the environment. This is reflected in the law discovered by the Russian scientist K.F. Roulier: “the results of the development (changes) of any object (organism) are determined by the ratio of its internal characteristics and the characteristics of the environment in which it is located.” This law is sometimes called the first environmental law because it is universal.

Organisms influence the environment by changing the gas composition of the atmosphere (H: as a result of photosynthesis), participate in the formation of soil, relief, climate, etc.

The limit of the influence of organisms on the habitat is described by another ecological law (Kurazhkovsky Yu.N.): each type of organism, consuming the substances it needs from the environment and releasing products of its vital activity into it, changes it in such a way that the habitat becomes unsuitable for its existence .

1.2.2. Ecological environmental factors and their classification.

The set of individual elements of the environment that influence organisms at at least one stage of individual development are called environmental factors.

According to the nature of origin, abiotic, biotic and anthropogenic factors are distinguished. (Slide 1)

Abiotic factors- these are the properties of inanimate nature (temperature, light, humidity, composition of air, water, soil, natural radiation background of the Earth, terrain), etc., which directly or indirectly affect living organisms.

Biotic factors- these are all forms of influence of living organisms on each other. The effect of biotic factors can be both direct and indirect, expressed in changes in environmental conditions, for example, changes in soil composition under the influence of bacteria or changes in the microclimate in the forest.

Mutual connections between individual species of organisms underlie the existence of populations, biocenoses and the biosphere as a whole.

Previously, human influence on living organisms was also classified as biotic factors, but now a special category of factors generated by humans is distinguished.

Anthropogenic factors- these are all forms of activity of human society that lead to changes in nature as a habitat and other species and directly affect their lives.

Human activity on the planet should be identified as a special force that has both direct and indirect effects on nature. Direct impacts include human consumption, reproduction and settlement of individual species of animals and plants, as well as the creation of entire biocenoses. Indirect impact is carried out by changing the habitat of organisms: climate, river regime, land conditions, etc. As the population grows and the technological level of mankind grows, the proportion of anthropogenic environmental factors is steadily increasing.

Environmental factors vary in time and space. Some environmental factors are considered to be relatively constant over long periods of time in the evolution of species. For example, gravity, solar radiation, salt composition of the ocean. Most environmental factors - air temperature, humidity, air speed - are very variable in space and time.

In accordance with this, depending on the regularity of exposure, environmental factors are divided into (Slide 2):

· regularly periodic , changing the strength of the impact due to the time of day, season of the year or the rhythm of the tides in the ocean. For example: a decrease in temperature in the temperate climate zone of northern latitude with the onset of winter, etc.

· irregularly periodic , catastrophic phenomena: storms, rainfalls, floods, etc.

· non-periodic, arising spontaneously, without a clear pattern, one-time. For example, the emergence of a new volcano, fires, human activity.

Thus, every living organism is influenced by inanimate nature, organisms of other species, including humans, and, in turn, affects each of these components.

In order of order, the factors are divided into primary And secondary .

Primary environmental factors have always existed on the planet, even before the appearance of living beings, and all living things have adapted to these factors (temperature, pressure, tides, seasonal and daily frequency).

Secondary environmental factors arise and change due to the variability of primary environmental factors (water turbidity, air humidity, etc.).

Based on their effect on the body, all factors are divided into direct action factors And indirect .

According to the degree of impact, they are divided into lethal (leading to death), extreme, limiting, disturbing, mutagenic, teratogenic, leading to deformities during individual development).

Each environmental factor is characterized by certain quantitative indicators: force, pressure, frequency, intensity, etc.

1.2.3. Patterns of the action of environmental factors on organisms. Limiting factor. Liebig's law of the minimum. Shelford's law of tolerance. The doctrine of ecological optimums of species. Interaction of environmental factors.

Despite the variety of environmental factors and the different nature of their origin, there are some general rules and patterns of their impact on living organisms. Any environmental factor can affect the body as follows (Slide):

· change the geographical distribution of species;

· change the fertility and mortality of species;

· cause migration;

· promote the emergence of adaptive qualities and adaptations in species.

The action of a factor is most effective at a certain value of the factor that is optimal for the body, and not at its critical values. Let us consider the patterns of the factor’s action on organisms. (Slide).

The dependence of the result of the action of an environmental factor on its intensity; the favorable range of action of the environmental factor is called optimum zone (normal life activities). The more significant the deviation of a factor’s action from the optimum, the more this factor inhibits the vital activity of the population. This range is called zone of oppression (pessimum) . The maximum and minimum transferable values ​​of a factor are critical points beyond which the existence of an organism or population is no longer possible. The range of action of a factor between critical points is called zone of tolerance (endurance) of the body in relation to this factor. The point on the x-axis that corresponds to the best indicator vital activity of the body, means the optimal value of the factor and is called optimum point. Since it is difficult to determine the optimum point, they usually talk about optimum zone or comfort zone. Thus, the points of minimum, maximum and optimum are three cardinal points , which determine the body’s possible reactions to a given factor. Environmental conditions in which any factor (or set of factors) goes beyond the comfort zone and has a depressing effect are called in ecology extreme .

The considered patterns are called "optimum rule" .

For organisms to live, a certain combination of conditions is necessary. If all environmental conditions are favorable, with the exception of one, then this condition becomes decisive for the life of the organism in question. It limits (limites) the development of the organism, therefore it is called limiting factor . That. limiting factor - an environmental factor whose significance goes beyond the limits of survival of the species.

For example, fish kills in water bodies in winter are caused by a lack of oxygen, carp do not live in the ocean (salt water), and the migration of soil worms is caused by excess moisture and lack of oxygen.

Initially, it was found that the development of living organisms is limited by the lack of any component, for example, mineral salts, moisture, light, etc. In the mid-19th century, the German organic chemist Eustace Liebig was the first to experimentally prove that plant growth depends on the nutrient element that is present in relatively minimal quantities. He called this phenomenon the law of the minimum; it is also called after the author Liebig's law . (Liebig barrel).

In modern formulation law of the minimum sounds like this: The endurance of an organism is determined by the weakest link in the chain of its environmental needs. However, as it turned out later, not only a deficiency, but also an excess of a factor can be limiting, for example, crop loss due to rain, oversaturation of the soil with fertilizers, etc. The concept that, along with a minimum, a maximum can also be a limiting factor was introduced 70 years after Liebig by the American zoologist W. Shelford, who formulated law of tolerance . According to According to the law of tolerance, the limiting factor in the prosperity of a population (organism) can be either a minimum or maximum environmental impact, and the range between them determines the amount of endurance (tolerance limit) or the ecological valence of the organism to this factor

The principle of limiting factors is valid for all types of living organisms - plants, animals, microorganisms and applies to both abiotic and biotic factors.

For example, competition from another species may become a limiting factor for the development of organisms of a given species. In agriculture, pests and weeds often become the limiting factor, and for some plants the limiting factor in development is the lack (or absence) of representatives of another species. For example, a new type of fig was brought to California from the Mediterranean, but it did not bear fruit until the only species of pollinating bees for it was brought from there.

In accordance with the law of tolerance, any excess of matter or energy turns out to be a pollutant.

Thus, excess water even in arid areas is harmful and water can be considered as a common pollutant, although it is absolutely necessary in optimal quantities. In particular, excess water prevents normal soil formation in the chernozem zone.

The broad ecological valency of a species in relation to abiotic environmental factors is indicated by adding the prefix “evry” and the narrow “steno” to the name of the factor. Species whose existence requires strictly defined environmental conditions are called stenobiont , and species adapting to an ecological situation with a wide range of changes in parameters - eurybiont .

For example, animals that can tolerate large temperature fluctuations are called eurythermic, a narrow temperature range is typical for stenothermic organisms. (Slide). Small changes in temperature have little effect on eurythermal organisms and can be disastrous for stenothermic organisms (Fig. 4). Euryhydroids And stenohydroid Organisms differ in their response to fluctuations in humidity. Euryhaline And stenohaline – have different reactions to the degree of salinity of the environment. Euryoic organisms are able to live in different places, A wall-mounted – exhibit strict requirements for the choice of habitat.

In relation to pressure, all organisms are divided into eurybates And stenobat or stopobats (deep sea fish).

In relation to oxygen they release euryoxybionts (crucian carp) and stenooxybiont s (grayling).

In relation to the territory (biotope) – eurytopic (great tit) and stenotopic (osprey).

In relation to food - euryphages (corvids) and stenophages , among which we can highlight ichthyophages (osprey), entomophages (buzzard, swift, swallow), herpetophagous (The bird is the secretary).

The ecological valencies of a species in relation to different factors can be very diverse, which creates a variety of adaptations in nature. The totality of environmental valences in relation to various environmental factors is ecological spectrum of the species .

The body's tolerance limit changes during the transition from one stage of development to another. Often young organisms turn out to be more vulnerable and more demanding of environmental conditions than adult individuals.

The most critical period from the point of view of the influence of various factors is the breeding period: during this period, many factors become limiting. The ecological valency for reproducing individuals, seeds, embryos, larvae, eggs is usually narrower than for adult non-reproducing plants or animals of the same species.

For example, many marine animals can tolerate brackish or fresh water with high chloride content, so they often enter upstream rivers. But their larvae cannot live in such waters, so the species cannot reproduce in the river and does not establish a permanent habitat here. Many birds fly to raise their chicks in places with a warmer climate, etc.

Until now we have been talking about the limit of tolerance of a living organism in relation to one factor, but in nature all environmental factors act together.

The optimal zone and limits of the body's endurance in relation to any environmental factor can shift depending on the combination in which other factors act simultaneously. This pattern is called interactions of environmental factors (constellation ).

For example, it is known that heat is easier to bear in dry rather than humid air; The risk of freezing is significantly greater in low temperatures with strong winds than in calm weather. For plant growth, in particular, an element such as zinc is necessary; it is often the limiting factor. But for plants growing in the shade, the need for it is less than for those in the sun. The so-called compensation of factors occurs.

However, mutual compensation has certain limits and it is impossible to completely replace one of the factors with another. The complete absence of water or at least one of the necessary elements of mineral nutrition makes plant life impossible, despite the most favorable combinations of other conditions. It follows that all environmental conditions necessary to support life play an equal role and any factor can limit the possibilities of existence of organisms - this is the law of equivalence of all living conditions.

It is known that each factor has different effects on different body functions. Conditions that are optimal for some processes, for example, for the growth of an organism, may turn out to be a zone of oppression for others, for example, for reproduction, and go beyond the limits of tolerance, that is, lead to death, for others. Therefore, the life cycle, according to which an organism primarily performs certain functions during certain periods - nutrition, growth, reproduction, settlement - is always consistent with seasonal changes in environmental factors, such as seasonality in the plant world, caused by the change of seasons.

Among the laws that determine the interaction of an individual or individual with his environment, we highlight rule of compliance of environmental conditions with the genetic predetermination of the organism . It claims that a species of organisms can exist until and to the extent that the natural environment surrounding it corresponds to the genetic capabilities of adapting this species to its fluctuations and changes. Every living species arose in specific environment, to one degree or another, has adapted to it and the further existence of the species is possible only in this or a similar environment. A sharp and rapid change in the living environment can lead to the fact that the genetic capabilities of a species will be insufficient to adapt to new conditions. This, in particular, is the basis for one of the hypotheses for the extinction of large reptiles with a sharp change in abiotic conditions on the planet: large organisms are less variable than small ones, so they need much more time to adapt. In this regard, radical transformations of nature are dangerous for today existing species, including for the person himself.

1.2.4. Adaptation of organisms to unfavorable environmental conditions

Environmental factors can act as:

· irritants and cause adaptive changes in physiological and biochemical functions;

· limiters , causing the impossibility of existence in these conditions;

· modifiers , causing anatomical and morphological changes in organisms;

· signals , indicating changes in other environmental factors.

In the process of adaptation to unfavorable environmental conditions, organisms were able to develop three main ways to avoid the latter.

Active path– helps to strengthen resistance, the development of regulatory processes that allow all vital functions of organisms to be carried out, despite unfavorable factors.

For example, warm-bloodedness in mammals and birds.

Passive way associated with the subordination of the vital functions of the body to changes in environmental factors. For example, the phenomenon hidden life , accompanied by suspension of vital activity when the reservoir dries up, cold weather, etc., up to the state imaginary death or suspended animation .

For example, dried plant seeds, their spores, as well as small animals (rotifers, nematodes) are able to withstand temperatures below 200 o C. Examples of anabiosis? Winter dormancy of plants, hibernation of vertebrates, preservation of seeds and spores in the soil.

The phenomenon in which there is temporary physiological rest in the individual development of some living organisms, caused by unfavorable environmental factors, is called diapause .

Avoidance of Adverse Effects– the development by the body of such life cycles in which the most vulnerable stages of its development are completed in the most favorable periods of the year in terms of temperature and other conditions.

The usual route for such adaptations is migration.

Evolutionary adaptations of organisms to environmental conditions, expressed in changes in their external and internal characteristics, are called adaptation . There are different types of adaptations.

Morphological adaptations. Organisms develop such features of their external structure that contribute to the survival and successful functioning of organisms in their usual conditions.

For example, the streamlined body shape of aquatic animals, the structure of succulents, and the adaptations of halophytes.

The morphological type of adaptation of an animal or plant, in which they have an external form that reflects the way they interact with their environment, is called life form of the species . In the process of adaptation to the same environmental conditions, different species can have a similar life form.

For example, whale, dolphin, shark, penguin.

Physiological adaptations manifest themselves in the peculiarities of the enzymatic set in the digestive tract of animals, determined by the composition of the food.

For example, providing moisture through the oxidation of fat in camels.

Behavioral adaptations– manifest themselves in the creation of shelters, movement in order to select the most favorable conditions, scaring away predators, hiding, school behavior, etc.

The adaptations of each organism are determined by its genetic predisposition. The rule of compliance of environmental conditions with genetic predetermination states: as long as the environment surrounding a certain species of organisms corresponds to the genetic capabilities of adaptation of this species to its fluctuations and changes, this species can exist. A sharp and rapid change in environmental conditions can lead to the fact that the speed of adaptive reactions will lag behind the change in environmental conditions, which will lead to the elimination of the species. The above fully applies to humans.

1.2.5. Main abiotic factors.

Let us recall once again that abiotic factors are properties of inanimate nature that directly or indirectly affect living organisms. Slide 3 shows the classification of abiotic factors.

Temperature is the most important climatic factor. Depends on her metabolic rate organisms and their geographical distribution. Any organism is capable of living within a certain temperature range. And although for different types of organisms ( eurythermic and stenothermic) these intervals are different, for most of them the zone of optimal temperatures at which vital functions are carried out most actively and efficiently is relatively small. The range of temperatures in which life can exist is approximately 300 C: from -200 to +100 C. But most species and most of their activity are confined to an even narrower temperature range. Some organisms, especially those in the dormant stage, can survive for at least some time at very low temperatures. Certain types of microorganisms, mainly bacteria and algae, are able to live and reproduce at temperatures close to the boiling point. The upper limit for hot spring bacteria is 88 C, for blue-green algae - 80 C, and for the most resistant fish and insects - about 50 C. As a rule, the upper limit values ​​of the factor are more critical than the lower ones, although many organisms near the upper limits of the tolerance range function more effectively.

Aquatic animals tend to have a narrower range of temperature tolerance than terrestrial animals because the temperature range in water is smaller than on land.

From the point of view of the impact on living organisms, temperature variability is extremely important. Temperatures ranging from 10 to 20 C (average 15 C) do not necessarily affect the body in the same way as a constant temperature of 15 C. The vital activity of organisms that are usually exposed to variable temperatures in nature is suppressed completely or partially or slowed down by the influence constant temperature. Using variable temperature, it was possible to accelerate the development of grasshopper eggs by an average of 38.6% compared to their development at a constant temperature. It is not yet clear whether the accelerating effect is due to temperature fluctuations themselves or to enhanced growth caused by a short-term increase in temperature and not compensated by a slowdown in growth when it decreases.

Thus, temperature is an important and very often limiting factor. Temperature rhythms largely control the seasonal and daily activity of plants and animals. Temperature often creates zonation and stratification in aquatic and terrestrial habitats.

Water physiologically necessary for any protoplasm. From an ecological point of view, it serves as a limiting factor both in terrestrial habitats and in aquatic habitats, where its quantity is subject to strong fluctuations, or where high salinity contributes to the loss of water by the body through osmosis. All living organisms, depending on their need for water, and therefore on differences in habitat, are divided into a number of ecological groups: aquatic or hydrophilic- permanently living in water; hygrophilic- living in very wet habitats; mesophilic- characterized by a moderate need for water and xerophilic- living in dry habitats.

Precipitation and humidity are the main quantities measured when studying this factor. The amount of precipitation depends mainly on the paths and nature of large movements of air masses. For example, winds blowing from the ocean leave most of the moisture on the slopes facing the ocean, resulting in a “rain shadow” behind the mountains, which contributes to the formation of the desert. Moving inland, the air accumulates a certain amount of moisture, and the amount of precipitation increases again. Deserts tend to be located behind high mountain ranges or along coastlines where winds blow from vast inland dry areas rather than from the ocean, such as the Nami Desert in South West Africa. The distribution of precipitation over the seasons is an extremely important limiting factor for organisms. The conditions created by uniformly distributed rainfall are completely different from those created by rainfall during one season. In this case, animals and plants have to endure periods of prolonged drought. As a rule, an uneven distribution of precipitation over the seasons is found in the tropics and subtropics, where the wet and dry seasons are often well defined. In the tropical zone, the seasonal rhythm of humidity regulates the seasonal activity of organisms, similar to the seasonal rhythm of heat and light in the temperate zone. Dew can be a significant and, in places with little rainfall, a very important contribution to total quantity precipitation.

Humidity- a parameter characterizing the content of water vapor in the air. Absolute humidity is the amount of water vapor per unit volume of air. Due to the dependence of the amount of vapor retained by air on temperature and pressure, the concept relative humidity is the ratio of the vapor contained in the air to the saturated vapor at a given temperature and pressure. Since in nature there is a daily rhythm of humidity - an increase at night and a decrease during the day, and its fluctuations vertically and horizontally, this factor, along with light and temperature, plays an important role in regulating the activity of organisms. Humidity modifies the effects of temperature altitude. For example, under humidity conditions close to critical, temperature has a more important limiting effect. Similarly, humidity plays a more critical role if the temperature is close to the extreme values. Large bodies of water significantly soften the climate of land, since water is characterized by a large latent heat of vaporization and melting. There are actually two main types of climate: continental with extremes of temperature and humidity and nautical, which is characterized by less sharp fluctuations, which is explained by the moderating influence of large bodies of water.

The supply of surface water available to living organisms depends on the amount of precipitation in a given area, but these values ​​do not always coincide. Thus, using underground sources, where water comes from other areas, animals and plants can receive more water than from receiving it with precipitation. Conversely, rainwater sometimes immediately becomes inaccessible to organisms.

Radiation from the Sun represents electromagnetic waves of various lengths. It is absolutely necessary for living nature, as it is the main external source of energy. The distribution spectrum of solar radiation energy outside the earth's atmosphere (Fig. 6) shows that about half of the solar energy is emitted in the infrared region, 40% in the visible and 10% in the ultraviolet and x-ray regions.

It must be borne in mind that the spectrum of electromagnetic radiation from the Sun is very wide (Fig. 7) and its frequency ranges affect living matter in different ways. The Earth's atmosphere, including the ozone layer, selectively, that is, selectively in frequency ranges, absorbs the energy of electromagnetic radiation from the Sun and mainly radiation with a wavelength of 0.3 to 3 microns reaches the Earth's surface. Longer and shorter wavelength radiation is absorbed by the atmosphere.

With increasing zenith distance of the Sun, the relative content of infrared radiation increases (from 50 to 72%).

Qualitative signs of light are important for living matter - wavelength, intensity and duration of exposure.

It is known that animals and plants respond to changes in the wavelength of light. Color vision is common in different groups of animals and is spotty: it is well developed in some species of arthropods, fish, birds and mammals, but in other species of the same groups it may be absent.

The rate of photosynthesis varies with changes in the wavelength of light. For example, when light passes through water, the red and blue parts of the spectrum are filtered out and the resulting greenish light is weakly absorbed by chlorophyll. However, red algae have additional pigments (phycoerythrins) that allow them to harness this energy and live at greater depths than green algae.

In both terrestrial and aquatic plants, photosynthesis is related to light intensity in a linear relationship up to an optimal level of light saturation, which in many cases is followed by a decrease in photosynthetic rate at high intensities of direct sunlight. In some plants, such as eucalyptus, photosynthesis is not inhibited by direct sunlight. In this case, compensation of factors takes place, as individual plants and entire communities adapt to different light intensities, becoming adapted to shade (diatoms, phytoplankton) or to direct sunlight.

The length of daylight, or photoperiod, is a “time switch” or trigger that includes a sequence of physiological processes leading to growth, flowering in many plants, molting and fat accumulation, migration and reproduction in birds and mammals, and diapause in insects. Some higher plants bloom as the day length increases (plants have a long day), others bloom when the day shortens (short-day plants). In many photoperiod-sensitive organisms, the biological clock setting can be altered by experimentally altering the photoperiod.

Ionizing radiation knocks electrons out of atoms and attaches them to other atoms to form pairs of positive and negative ions. Its source is radioactive substances contained in rocks, in addition, it comes from space.

Different types of living organisms differ greatly in their ability to withstand large doses of radiation exposure. For example, a dose of 2 Sv (siver) causes the death of the embryos of some insects at the crushing stage, a dose of 5 Sv leads to sterility of some types of insects, a dose of 10 Sv is absolutely lethal for mammals. Most studies show that rapidly dividing cells are most sensitive to radiation.

The effects of low doses of radiation are more difficult to assess because they can cause long-term genetic and somatic effects. For example, irradiation of a pine tree with a dose of 0.01 Sv per day for 10 years caused a slowdown in growth rate similar to a single dose of 0.6 Sv. An increase in the level of radiation in the environment above the background level leads to an increase in the frequency of harmful mutations.

In higher plants, sensitivity to ionizing radiation is directly proportional to the size of the cell nucleus, or more precisely to the volume of chromosomes or DNA content.

In higher animals no such simple relationship has been found between sensitivity and cell structure; For them, the sensitivity of individual organ systems is more important. Thus, mammals are very sensitive even to low doses of radiation due to the fact that the rapidly dividing hematopoietic tissue of the bone marrow is easily damaged by irradiation. Even very low levels of chronically acting ionizing radiation can cause the growth of tumor cells in bones and other sensitive tissues, which may not appear until many years after exposure.

Gas composition atmosphere is also an important climatic factor (Fig. 8). Approximately 3-3.5 billion years ago, the atmosphere contained nitrogen, ammonia, hydrogen, methane and water vapor, and there was no free oxygen in it. The composition of the atmosphere was largely determined by volcanic gases. Due to the lack of oxygen, there was no ozone screen to block ultraviolet radiation from the Sun. Over time, due to abiotic processes, oxygen began to accumulate in the planet’s atmosphere, and the formation of the ozone layer began. Around the middle of the Paleozoic, oxygen consumption equaled its production; during this period, the O2 content in the atmosphere was close to modern levels - about 20%. Further, from the middle of the Devonian, fluctuations in oxygen content are observed. At the end of the Paleozoic, there was a noticeable decrease in oxygen content and an increase in carbon dioxide content, down to about 5% of modern levels, which led to climate change and, apparently, gave rise to abundant “autotrophic” blooms that created reserves of fossil hydrocarbon fuels. This was followed by a gradual return to an atmosphere low in carbon dioxide and high in oxygen, after which the O2/CO2 ratio remained in a state of so-called oscillatory steady-state equilibrium.

Currently, the Earth's atmosphere has the following composition: oxygen ~21%, nitrogen ~78%, carbon dioxide ~0.03%, inert gases and impurities ~0.97%. Interestingly, the concentrations of oxygen and carbon dioxide are limiting for many higher plants. In many plants, it is possible to increase the efficiency of photosynthesis by increasing the concentration of carbon dioxide, but it is little known that decreasing the concentration of oxygen can also lead to an increase in photosynthesis. In experiments on legumes and many other plants, it was shown that reducing the oxygen content in the air to 5% increases the intensity of photosynthesis by 50%. Nitrogen also plays an extremely important role. This is the most important biogenic element involved in the formation of protein structures of organisms. Wind has a limiting effect on the activity and distribution of organisms.

Wind It can even change the appearance of plants, especially in those habitats, for example in alpine zones, where other factors have a limiting effect. It has been experimentally shown that in open mountain habitats the wind limits plant growth: when a wall was built to protect the plants from the wind, the height of the plants increased. Storms are of great importance, although their effect is purely local. Hurricanes and ordinary winds can transport animals and plants over long distances and thereby change the composition of communities.

Atmospheric pressure, apparently, is not a direct limiting factor, but it is directly related to weather and climate, which have a direct limiting effect.

Aquatic conditions create a unique habitat for organisms, differing from terrestrial ones primarily in density and viscosity. Density water approximately 800 times, and viscosity approximately 55 times higher than air. Together with density And viscosity the most important physical and chemical properties of the aquatic environment are: temperature stratification, that is, temperature changes along the depth of the water body and periodic temperature changes over time, and also transparency water, which determines the light regime under its surface: photosynthesis of green and purple algae, phytoplankton, and higher plants depends on transparency.

As in the atmosphere, an important role is played gas composition aquatic environment. In aquatic habitats, the amount of oxygen, carbon dioxide and other gases dissolved in water and therefore available to organisms varies greatly over time. In reservoirs with a high content of organic matter, oxygen is a limiting factor of paramount importance. Despite the better solubility of oxygen in water compared to nitrogen, even in the most favorable case, water contains less oxygen than air, approximately 1% by volume. Solubility is affected by water temperature and the amount of dissolved salts: as the temperature decreases, the solubility of oxygen increases, and as the salinity increases, it decreases. The supply of oxygen in water is replenished due to diffusion from the air and photosynthesis of aquatic plants. Oxygen diffuses into water very slowly, diffusion is facilitated by wind and water movement. As already mentioned, the most important factor ensuring the photosynthetic production of oxygen is light penetrating the water column. Thus, the oxygen content of water varies depending on the time of day, season and location.

The carbon dioxide content of water can also vary greatly, but carbon dioxide behaves differently from oxygen, and its ecological role is poorly understood. Carbon dioxide is highly soluble in water; in addition, CO2, formed during respiration and decomposition, as well as from soil or underground sources, enters water. Unlike oxygen, carbon dioxide reacts with water:

to form carbonic acid, which reacts with lime to form carbonates CO22- and bicarbonates HCO3-. These compounds maintain the concentration of hydrogen ions at a level close to neutral. A small amount of carbon dioxide in water increases the intensity of photosynthesis and stimulates the development processes of many organisms. A high concentration of carbon dioxide is a limiting factor for animals, since it is accompanied by a low oxygen content. For example, if the content of free carbon dioxide in the water is too high, many fish die.

Acidity- the concentration of hydrogen ions (pH) is closely related to the carbonate system. The pH value changes in the range 0? pH? 14: at pH=7 the medium is neutral, at pH<7 - кислая, при рН>7 - alkaline. If acidity does not approach extreme values, then communities are able to compensate for changes in this factor - the community's tolerance to the pH range is very significant. Acidity can serve as an indicator of speed general metabolism communities. Waters with low pH contain few nutrients, so productivity is extremely low.

Salinity- content of carbonates, sulfates, chlorides, etc. - is another significant abiotic factor in water bodies. There are few salts in fresh waters, of which about 80% are carbonates. The content of minerals in the world's oceans averages 35 g/l. Open ocean organisms are generally stenohaline, whereas coastal brackish water organisms are generally euryhaline. The salt concentration in the body fluids and tissues of most marine organisms is isotonic with the salt concentration in seawater, so there are no problems with osmoregulation.

Flow not only greatly influences the concentration of gases and nutrients, but also directly acts as a limiting factor. Many river plants and animals are morphologically and physiologically specially adapted to maintaining their position in the flow: they have well-defined limits of tolerance to the flow factor.

Hydrostatic pressure in the ocean is of great importance. With immersion in water of 10 m, the pressure increases by 1 atm (105 Pa). In the deepest part of the ocean the pressure reaches 1000 atm (108 Pa). Many animals are able to tolerate sudden fluctuations in pressure, especially if they do not have free air in their bodies. Otherwise, gas embolism may develop. High pressures, characteristic of great depths, as a rule, inhibit vital processes.

Soil is the layer of substance lying on top of the rocks of the earth's crust. The Russian scientist and naturalist Vasily Vasilyevich Dokuchaev in 1870 was the first to consider soil as a dynamic, rather than inert, medium. He proved that the soil is constantly changing and developing, and chemical, physical and biological processes take place in its active zone. Soil is formed through a complex interaction of climate, plants, animals and microorganisms. Soviet academician soil scientist Vasily Robertovich Williams gave another definition of soil - it is a loose surface horizon of land capable of producing plant crops. Plant growth depends on the content of essential nutrients in the soil and its structure.

Soil composition includes four main structural components: mineral base (usually 50-60% of the total soil composition), organic matter (up to 10%), air (15-25%) and water (25-30%).

Soil mineral skeleton- This is an inorganic component that was formed from the parent rock as a result of its weathering.

Over 50% of the mineral composition of the soil is occupied by silica SiO2, from 1 to 25% by alumina Al2O3, from 1 to 10% by iron oxides Fe2O3, from 0.1 to 5% by oxides of magnesium, potassium, phosphorus, and calcium. The mineral elements that form the substance of the soil skeleton vary in size: from boulders and stones to sand grains - particles with a diameter of 0.02-2 mm, silt - particles with a diameter of 0.002-0.02 mm and the smallest particles of clay less than 0.002 mm in diameter. Their ratio determines mechanical structure of the soil . It is of great importance for agriculture. Clays and loams, containing approximately equal amounts of clay and sand, are usually suitable for plant growth, as they contain sufficient nutrients and are able to retain moisture. Sandy soils drain faster and lose nutrients due to leaching, but they are more beneficial for early harvests because their surface dries out faster in the spring than clay soils, resulting in better warming. As the rockiness of the soil increases, its ability to hold water decreases.

organic matter soil is formed by the decomposition of dead organisms, their parts and excrement. Organic residues that have not completely decomposed are called litter, and the final product of decomposition - an amorphous substance in which it is no longer possible to recognize the original material - is called humus. Thanks to its physical and chemical properties, humus improves soil structure and aeration, and also increases the ability to retain water and nutrients.

Simultaneously with the process of humification, vital elements are transferred from organic compounds to inorganic ones, for example: nitrogen - into ammonium ions NH4+, phosphorus - into orthophosphathions H2PO4-, sulfur - into sulfathions SO42-. This process is called mineralization.

Soil air, like soil water, is located in the pores between soil particles. Porosity increases from clays to loams and sands. Free gas exchange occurs between the soil and the atmosphere, resulting in a similar gas composition in both environments. Usually, due to the respiration of the organisms inhabiting it, the soil air contains slightly less oxygen and more carbon dioxide than the atmospheric air. Oxygen is necessary for plant roots, soil animals and decomposer organisms that decompose organic matter into inorganic components. If waterlogging occurs, soil air is replaced by water and conditions become anaerobic. The soil gradually becomes acidic as anaerobic organisms continue to produce carbon dioxide. The soil, if it is not rich in bases, can become extremely acidic, and this, along with the depletion of oxygen reserves, has an adverse effect on soil microorganisms. Prolonged anaerobic conditions lead to plant death.

Soil particles hold a certain amount of water around them, which determines soil moisture. Part of it, called gravitational water, can freely seep deep into the soil. This leads to the leaching of various minerals from the soil, including nitrogen. Water may also be retained around individual colloidal particles as a thin, strong, cohesive film. This water is called hygroscopic. It is adsorbed on the surface of particles due to hydrogen bonds. This water is the least accessible to plant roots and is the last to be retained in very dry soils. The amount of hygroscopic water depends on the content of colloidal particles in the soil, therefore in clayey soils there is much more of it - approximately 15% of the soil mass - than in sandy soils - approximately 0.5%. As layers of water accumulate around soil particles, it begins to fill first the narrow pores between these particles, and then spreads into increasingly wider pores. Hygroscopic water gradually turns into capillary water, which is held around soil particles by surface tension forces. Capillary water can rise through narrow pores and channels from the groundwater level. Plants easily absorb capillary water, which plays the greatest role in their regular supply of water. Unlike hygroscopic moisture, this water evaporates easily. Fine-textured soils, such as clays, hold more capillary water than coarse-textured soils, such as sands.

Water is necessary for all soil organisms. It enters living cells by osmosis.

Water is also important as a solvent for nutrients and gases absorbed from the aqueous solution by plant roots. It takes part in the destruction of the parent rock underlying the soil and in the process of soil formation.

The chemical properties of the soil depend on the content of minerals that are present in it in the form of dissolved ions. Some ions are poisonous for plants, others are vital. The concentration of hydrogen ions in the soil (acidity) pH>7, that is, on average close to a neutral value. The flora of such soils is especially rich in species. Calcareous and saline soils have pH = 8...9, and peat soils - up to 4. Specific vegetation develops on these soils.

The soil is home to many species of plant and animal organisms that influence its physicochemical characteristics: bacteria, algae, fungi or protozoa, worms and arthropods. Their biomass in different soils is equal (kg/ha): bacteria 1000-7000, microscopic fungi - 100-1000, algae 100-300, arthropods - 1000, worms 350-1000.

Synthesis and biosynthesis processes take place in the soil; various chemical reactions transformations of substances associated with the life of bacteria. In the absence of specialized groups of bacteria in the soil, their role is played by soil animals, which convert large plant residues into microscopic particles and thus make organic substances available to microorganisms.

Organic substances are produced by plants using mineral salts, solar energy and water. Thus, the soil loses the minerals that plants took from it. In forests, some nutrients return to the soil through leaf fall. Cultivated plants Over a period of time, significantly more nutrients are removed from the soil than are returned to it. Typically, nutrient losses are replenished by applying mineral fertilizers, which generally cannot be directly used by plants and must be transformed by microorganisms into a biologically accessible form. In the absence of such microorganisms, the soil loses fertility.

The main biochemical processes take place in the upper layer of soil up to 40 cm thick, since it contains the largest number of microorganisms. Some bacteria participate in the transformation cycle of only one element, while others participate in the transformation cycles of many elements. If bacteria mineralize organic matter - decompose organic matter into inorganic compounds, then protozoa destroy excess bacteria. Earthworms, beetle larvae, and mites loosen the soil and thereby contribute to its aeration. In addition, they process organic substances that are difficult to break down.

Abiotic factors in the habitat of living organisms also include relief factors (topography) . The influence of topography is closely related to other abiotic factors, as it can strongly influence local climate and soil development.

The main topographic factor is altitude above sea level. With altitude, average temperatures decrease, daily temperature differences increase, precipitation, wind speed and radiation intensity increase, atmospheric pressure and gas concentrations decrease. All these factors influence plants and animals, causing vertical zonation.

Mountain ranges may serve as climate barriers. Mountains also serve as barriers to the spread and migration of organisms and can play the role of a limiting factor in the processes of speciation.

Another topographic factor is slope exposure . In the northern hemisphere, south-facing slopes receive more sunlight, so the light intensity and temperature here are higher than on valley floors and northern-facing slopes. In the southern hemisphere the opposite situation occurs.

An important relief factor is also slope steepness . Steep slopes are characterized by rapid drainage and soil washing away, so the soils here are thin and drier. If the slope exceeds 35b, soil and vegetation usually do not form, but a scree of loose material is created.

Among abiotic factors, special attention deserves fire or fire . Currently, ecologists have come to the unequivocal conclusion that fire should be considered as one of the natural abiotic factors along with climatic, edaphic and other factors.

Fires as an environmental factor come in various types and leave behind various consequences. Crown or wild fires, that is, very intense and uncontrollable, destroy all vegetation and all soil organic matter, while the consequences of ground fires are completely different. Crown fires have a limiting effect on most organisms - the biotic community has to start all over again with what little is left, and many years must pass before the site becomes productive again. Ground fires, on the contrary, have a selective effect: for some organisms they are a more limiting factor, for others - a less limiting factor and thus contribute to the development of organisms with high tolerance to fires. In addition, small ground fires complement the action of bacteria, decomposing dead plants and accelerating the conversion of mineral nutrients into a form suitable for use by new generations of plants.

If ground fires occur regularly every few years, little dead wood remains on the ground, which reduces the likelihood of crown fires. In forests that have not burned for more than 60 years, so much combustible litter and dead wood accumulates that when it ignites, a crown fire is almost inevitable.

Plants have developed specialized adaptations to fire, just as they have done to other abiotic factors. In particular, the buds of cereals and pines are hidden from fire in the depths of tufts of leaves or needles. In periodically burned habitats, these plant species benefit because fire promotes their preservation by selectively promoting their flourishing. Broad-leaved species do not have protective devices against fire; it is destructive for them.

Thus, fires maintain the stability of only some ecosystems. For deciduous and humid tropical forests, the balance of which was formed without the influence of fire, even a ground fire can cause great damage, destroying the humus-rich upper soil horizon, leading to erosion and leaching of nutrients from it.

The question “to burn or not to burn” is unusual for us. The effects of burning can be very different depending on the time and intensity. Through carelessness, people often cause an increase in the frequency of wild fires, so it is necessary to actively fight for fire safety in forests and recreation areas. In no case does a private person have the right to intentionally or accidentally cause a fire in nature. However, it is necessary to know that the use of fire by specially trained people is part of proper land management.

For abiotic conditions, all the considered laws of the influence of environmental factors on living organisms are valid. Knowledge of these laws allows us to answer the question: why in different regions planets formed different ecosystems? The main reason is the unique abiotic conditions of each region.

Populations are concentrated in a certain area and cannot be distributed everywhere with the same density because they have a limited range of tolerance to environmental factors. Consequently, each combination of abiotic factors is characterized by its own types of living organisms. Many variants of combinations of abiotic factors and species of living organisms adapted to them determine the diversity of ecosystems on the planet.

1.2.6. Main biotic factors.

The distribution areas and numbers of organisms of each species are limited not only by the conditions of the external inanimate environment, but also by their relationships with organisms of other species. The immediate living environment of an organism constitutes its biotic environment , and the factors of this environment are called biotic . Representatives of each species are able to exist in an environment where connections with other organisms provide them with normal living conditions.

The following forms of biotic relationships are distinguished. If we denote positive results of relationships for an organism with a “+” sign, negative results with a “-” sign, and the absence of results with a “0” sign, then the types of relationships found in nature between living organisms can be presented in the form of a table. 1.

This schematic classification gives general idea about the diversity of biotic relationships. Let us consider the characteristic features of relationships of various types.

Competition is the most comprehensive type of relationship in nature, in which two populations or two individuals influence each other in the struggle for the conditions necessary for life negative .

Competition may be intraspecific And interspecific . Intraspecific competition occurs between individuals of the same species, interspecific competition occurs between individuals of different species. Competitive interaction may concern:

· living space,

· food or nutrients,

· places of shelter and many other vital factors.

Advantages in competition are achieved by species in various ways. Given equal access to a common resource, one type may have an advantage over another due to:

more intensive reproduction

consuming more food or solar energy,

· ability to better protect oneself,

· adapt to a wider range of temperatures, light levels or concentrations of certain harmful substances.

Interspecific competition, regardless of what underlies it, can lead either to the establishment of equilibrium between two species, or to the replacement of the population of one species by the population of another, or to the fact that one species will displace another to another place or force it to move to another place. use of other resources. It has been established that two species identical in ecological terms and needs cannot coexist in one place and sooner or later one competitor displaces the other. This is the so-called exclusion principle or Gause principle.

Populations of some species of living organisms avoid or reduce competition by moving to another region with conditions acceptable to them, or by switching to more inaccessible or difficult-to-digest food, or by changing the time or place of food production. For example, hawks feed during the day, owls at night; lions hunt larger animals, and leopards hunt smaller ones; Tropical forests are characterized by the established stratification of animals and birds into tiers.

From Gause's principle it follows that each species in nature occupies a certain unique place. It is determined by the position of the species in space, the functions it performs in the community and its relationship to the abiotic conditions of existence. The place occupied by a species or organism in an ecosystem is called an ecological niche. Figuratively speaking, if a habitat is like the address of organisms of a given species, then an ecological niche is a profession, the role of an organism in its habitat.

A species occupies its ecological niche in order to perform the function it has conquered from other species in its own unique way, thus mastering its habitat and at the same time shaping it. Nature is very economical: even two species occupying the same ecological niche cannot exist sustainably. In competition, one species will displace another.

An ecological niche as a functional place of a species in the system of life cannot remain empty for a long time - this is evidenced by the rule of mandatory filling of ecological niches: an empty ecological niche is always naturally filled. An ecological niche as a functional place of a species in an ecosystem allows a form capable of developing new adaptations to fill this niche, but sometimes this requires considerable time. Often, empty ecological niches that seem empty to a specialist are just a deception. Therefore, a person should be extremely careful with conclusions about the possibility of filling these niches through acclimatization (introduction). Acclimatization is a set of measures to introduce a species into new habitats, carried out in order to enrich natural or artificial communities with organisms useful to humans.

The heyday of acclimatization occurred in the twenties and forties of the twentieth century. However, as time passed, it became obvious that either the experiments of acclimatization of species were unsuccessful, or, worse, brought very negative results - the species became pests or spread dangerous diseases. For example, with the Far Eastern bee acclimatized in the European part, mites were introduced, which were the causative agents of the disease varroatosis, which killed a large number of bee colonies. It could not have been otherwise: new species placed in a foreign ecosystem with an actually occupied ecological niche displaced those who were already doing similar work. New species did not meet the needs of the ecosystem, sometimes had no enemies and therefore could reproduce rapidly.

A classic example of this is the introduction of rabbits to Australia. In 1859, rabbits were brought to Australia from England for sport hunting. Natural conditions turned out to be favorable for them, and local predators - dingoes - were not dangerous, since they did not run fast enough. As a result, the rabbits multiplied so much that they destroyed the vegetation of pastures in vast areas. In some cases, the introduction of a natural enemy of an alien pest into the ecosystem brought success in the fight against the latter, but not everything is as simple as it seems at first glance. An introduced enemy will not necessarily focus on exterminating its usual prey. For example, foxes, introduced to Australia to kill rabbits, found easier prey - local marsupials - in abundance, without causing much trouble to the intended victim.

Competitive relationships are clearly observed not only at the interspecific, but also at the intraspecific (population) level. As the population grows, when the number of its individuals approaches saturation, internal physiological mechanisms regulation: mortality increases, fertility decreases, stressful situations, fights. Population ecology studies these issues.

Competitive relations are one of the most important mechanisms for the formation of the species composition of communities, the spatial distribution of population species and the regulation of their numbers.

Since the structure of the ecosystem is dominated by food interactions, the most characteristic form of interaction between species in trophic chains is predation , in which an individual of one species, called the predator, feeds on organisms (or parts of organisms) of another species, called the prey, and the predator lives separately from the prey. In such cases, the two species are said to be involved in a predator-prey relationship.

Prey species have evolved a number of defense mechanisms to avoid becoming easy prey for predators: the ability to run or fly quickly, the release of chemicals with an odor that repels or even poison the predator, the possession of thick skin or shell, protective coloration or the ability to change color.

Predators also have several ways of preying on prey. Carnivores, unlike herbivores, are usually forced to pursue and overtake their prey (compare, for example, herbivorous elephants, hippos, cows with carnivorous cheetahs, panthers, etc.). Some predators are forced to run quickly, others achieve their goal by hunting in packs, while others catch mainly sick, wounded and inferior individuals. Another way to provide oneself with animal food is the path that man took - the invention of fishing gear and the domestication of animals.

Unlike heat, light, humidity, soil, relief in itself does not act as a direct environmental factor. But its character to a certain extent determines the action of abiotic factors and affects the living conditions of plants. Depending on the scale and detail, there are several relief forms:

torque(mountains, lowlands, crevices and depressions):

mesorelief(steppe saucers, karst depressions, ravines, gullies, dunes, hills)

microrelief(pits, small depressions, tree trunk elevations, hummocks).

Each of these forms plays a certain role in the formation of a complex of environmental factors for plants.

Torque

Torsion has the most significant influence on the formation of plant groups. As an example, we can recall vertical zonation in the mountains, where every 100 m of ascent is accompanied by a decrease in temperature by an average of 0.5 ° C. The temperature gradient can fluctuate depending on the characteristics of the mountains and the time of year. For the Caucasus Range it is 0.48 ° C, for the Alps - 0.51 ° C, for the mountains of California - 0.75 ° C. The temperature gradient of the summer period is greater than the winter (Table 7.1). With altitude, the average temperature decreases, the daily temperature difference increases, the amount of precipitation, wind speed and intensity of solar radiation increases, and pressure decreases. Due to this, in mountainous areas, as one rises, a vertical zonality in the distribution of vegetation is observed, which corresponds to a change in zones along latitude from the equator to the pole (Fig. 7.1).

Table 7.1

Change temperature gradient depending on the time of year

(According to V.S. Gulisashvili, 1956)

Observation location	Gradient value in degrees
	winter	spring	summer	autumn	average
Caucasus ridge
Harz mountain range
Eastern Alps (northern slopes)
Mount Etna
North West India
Rocky Mountains (North America)

Rice. 7.1. Vertical and latitudinal tonality of vegetation

A typical example of vertical zonation of vegetation is the highest Himalayan mountains on the planet. They are distinguished by the diversity and richness of plant zones:

From the foot of the mountains in Hindustan to a height of 1000 m, humid tropics rise along the southern slope with huge evergreen ficuses, numerous large trees, on which various epiphytic orchids and ferns settle. Tree trunks intertwined with vines. Along with growing bamboo and giant grasses (up to 3 - 4 m tall)

The second subtropical belt of evergreen forests is located at an altitude of 1000-2000 m and is formed by subtropical conifers, palms, mimosa and the like;

The third belt is located at an altitude of 2000 - 2800 m, it is composed of evergreen oaks, walnut, Himalayan cedar and the like;

The fourth belt, extending to an altitude of 3500 m, consists of Webian fir, Scots pine and other boreal conifers;

The fifth belt consists of shrubs, the most common of which are rhododendrons;

The sixth belt is formed by high-mountain meadows of the boreal type;

Above are cold mountain deserts and primordial snow.

The factors that determine altitude explain the change from

height of temperature, amount of precipitation, atmospheric pressure. In addition, the highlands are characterized by low temperatures (frequent frosts), strong winds, and low carbon dioxide content. Vegetation is influenced by the nature of the rocks and the exposure and steepness of the slopes.

The intensity of solar radiation in the mountains is higher than on the plain, due to some rarefaction of the atmosphere and its transparency. Thus, in the highlands of the Pamirs, illumination during the daytime is about 130,000 lux, that is, almost as much as at the boundary of the earth’s atmosphere. The value of the solar constant increases with height, which is defined as the amount of solar energy falling on 1 cm2 of a horizontal surface per unit of time (Table 7.2). At the upper boundary of the atmosphere it averages 1.94 cal/(cm2 min.). In addition, at this altitude, ultraviolet radiation, which is harmful in high doses, is much more intense.

Table 7.2

Solar radiation intensity at different altitudes above sea level

(According to N. N. Kalitin and V. S. Gulisashvili, 1956)

In some areas, on clear nights, especially in winter, the phenomenon of temperature inversion is observed - the air on the slopes and peaks is warmer up to a certain height than in the valleys. It is believed that at night, cold air descends from the mountains, displacing warm air upward. Heat distribution largely depends on the exposure and steepness of the slopes (Table 7.3). Gentle slopes, with the same exposure, both in clear and cloudy weather, receive more heat than steep ones. That is, the steeper the slope, the less heat it receives. In northern latitudes, southern slopes with the same steepness, in any weather, receive more heat than northern ones. This redistribution of climatic characteristics associated with relief affects the formation of vegetation. On the southern slopes, forest phytocenoses are formed from xerophytic tree species (pine, oak), and on the slopes of northern exposure - from mesophytic tree species (beech, spruce). In addition, the same wood on southern slopes rises to a greater height than on northern slopes (Table 7.4). The height of the alpine forest border on slopes of a certain exposure is quite indicative (Table 7.5). The alpine border of the forest and the boundaries of the distribution of woody vegetation on the southern, southwestern and southeastern slopes rise higher.

Table 7.3

Dependence of thermal regime on exposure and slope steepness

(According to V.S. Gulisashvili, 1956)

Place observations	steepness slope, degree	The amount of heat for the growing season from April to August, (g cal) / 1 cm2
		in clear weather	in cloudy weather
total radiation
horizontal surface
southern slope
eastern slope
western slope
northern slope
southern slope
eastern slope
western slope
northern slope

Table 7.4

The upper limit of the distribution of forest species in the mountains of Primorsky Krai(43°N latitude)

(According to L. S. Berg and V. S. Gulisashvili, 1956)

Table 7.5

Influence of slope exposure on the alpine forest edge

(According to V. Z. Gulisashvili, 1956)

slope exposure	Altitude of the alpine forest boundary in the Swiss Alps,	Maximum height of spruce distribution, g.
Southeast
Pivdenno-western
Western
Northwestern
Northern
Northeast
Eastern

The hydrological regime in the mountains is quite different. In the mountain ranges of the Alps and Carpathians. In the Western Caucasus, humidity is present in sufficient quantities. In the Pamir and Tien Shan mountains, plants live in conditions of significant drought. Peculiar conditions develop directly near the massifs of snow and ice. In general, high-altitude conditions for plants are quite critical, which affects their structure, physiology, and development.

The peculiarity of the distribution of plants in the mountains is due to the fact that specific environmental conditions on each slope differ in individual massifs. This is explained by the very peculiarities of the geological structure of a particular mountain, the processes of its destruction and overgrowth. Therefore, a significant mosaic of environmental conditions is formed on the slopes, which subsequently leads to the formation of specific plant communities. For example, within the Alpine belt alone, completely different (according to environmental factors) growth conditions arise: dry and swampy, steep slopes without snow cover and places where snow remains throughout the year, areas protected from the wind and such that they are constantly blown (Fig. 7.2).

Alpine plants are characterized by short stature. Regardless of the location of the mountain ranges, shrubs and shrubs, creeping, rosette perennial grasses, turf grasses and sedges, mosses and lichens predominate here. But sometimes, for example, in the Southern Andes and Africa, in the highlands you can observe tree-like rosette plants with tall columnar trunks. Another characteristic feature of highland plants is the large mass of the underground part of the plants above the above-ground part. The short stature of high-mountain plants is associated with the effects of low temperatures, strong winds and the formative effects of radiation, because short-wave radiation slows down growth processes. The predominant importance of these abiotic conditions is confirmed by experiments on the transfer of fairly tall plants from lowlands to mountains. The results indicate that tall plants located at high altitudes adapt to new conditions after 3-4 years, stop growing and become stunted.

Rice. 7.2. Mosaic distribution of plant and vegetation types in the Alpine belt over a small area

Alpine plants also have a number of anatomical adaptations for protection from solar radiation and moisture conservation:

Thickened integumentary tissues;

Enhanced development of mechanical tissues;

Reduction in cell size;

Reduction in size and increase in the number of stomata;

Edges and waxy coating.

The last adaptation is not universal - in the mountains there are quite often plants without an edge or without a waxy cover.

Low temperatures and intense lighting ensure the formation of anthocyanins in plants, which creates a range of colors in the color of different parts of plants. The combination of rich colors of large flowers and small leaves is a characteristic feature of alpine plants.

Anthocyanins - pigments from the group of flavonoids contained in the cell sap of plants, fruits, leaves of plants, coloring them red, purple, blue or combinations thereof.

The main physiological processes in alpine plants occur very intensively. First of all, this concerns gas exchange. At high altitudes, photosynthesis occurs very intensively - 50-100 mg of CO2 per 1 g of leaf is absorbed in 1:00. In some plants, light saturation is not even observed; photosynthetic activity constantly increases with increasing illumination. The influence of low temperatures in high altitude conditions is manifested in an increase in the concentration of soluble carbohydrates, organic acids (for example, ascorbic acid), and aromatic substances. That is why alpine plants are highly valued in the food and medical industries, beekeeping, and as fodder. A characteristic feature of high-mountain plants is the increased intensity of redox processes and increased enzyme activity even at low temperatures. Most researchers note increased respiration of plants at altitude, which leads to an increase in energy released during the breakdown of complex compounds.

The seasonal development of plants changes significantly when climbing into the mountains. The higher it is, the later the snow melts in the spring and still falls in the fall, the shorter the growing season. Climbing the mountains in one day, you can observe all phases of the development of plants of one species: the flowering phase, budding, and leaf opening.

Different plant species respond differently to altitudinal zonation. Some have a wide altitudinal range and grow in different zones, others have a very narrow ecological adaptability. For example, blueberries (Vaccinium myrtillus) in the Carpathians, and fescue (Festuca valesiaca) in the Caucasus rise to the Alpine belt. These species have high ecological plasticity.

Mountain ranges quite often act as a kind of climatic barrier and a barrier to the spread of various plant species. A typical example is the Atanama Desert in Chile, which was formed by mountains trapping rain clouds. By the way, in Chile on the ocean coast there are so-called “fog forests”. They are located on mountain slopes, which also trap rain clouds. The unique conditions are also created because the cold ocean Humboldt Current approaches the shores. Due to the temperature difference, fog constantly forms here. This creates specific environmental conditions for plant growth. There are many other similar examples. In Central Asia there is the Pamir Highlands (Russia), which is located in the shadow of the highest mountains on Earth. But the Himalayas stand in the way of the movement of moist air masses into the interior of the continent. It was in this zone of influence that the Pamir highlands fell, where a high-mountain desert was formed (average altitude above sea level 4000 m). Its territory receives very little precipitation - from 15 to 150 mm per year. At the same time, there is intense evaporation, low humidity and high air temperature. Thanks to these features, unique plant groups have formed in different areas of the Pamir Highlands. In the southern part they resemble dry alpine meadows, in the central part they resemble the poor Kovylny steppe, and in the eastern part they resemble a desert.

These are factors of inanimate nature that directly or indirectly affect the body - light, temperature, humidity, the chemical composition of the air, water and soil environment, etc. (i.e., properties of the environment, the occurrence and impact of which does not directly depend on the activity of living organisms).

Light

(solar radiation) is an environmental factor characterized by the intensity and quality of the radiant energy of the Sun, which is used by photosynthetic green plants to create plant biomass. Sunlight reaching the Earth's surface is the main source of energy for maintaining the thermal balance of the planet, the water metabolism of organisms, the creation and transformation of organic matter by the autotrophic element of the biosphere, which ultimately makes it possible to form an environment capable of satisfying the vital needs of organisms.

The biological effect of sunlight is determined by its spectral composition [show] ,

The spectral composition of sunlight is divided into

• infrared rays (wavelength more than 0.75 microns)
• visible rays (0.40-0.75 µm) and
• ultraviolet rays (less than 0.40 microns)

Different parts of the solar spectrum have unequal biological effects.

Infrared, or thermal, rays carry the bulk of thermal energy. They account for about 49% of the radiant energy that is perceived by living organisms. Thermal radiation is well absorbed by water, the amount of which in organisms is quite large. This leads to heating of the entire body, which is of particular importance for cold-blooded animals (insects, reptiles, etc.). In plants, the most important function of infrared rays is to carry out transpiration, through which excess heat is removed from the leaves by water vapor, as well as to create optimal conditions for the entry of carbon dioxide through the stomata.

Visible spectrum make up about 50% of the radiant energy reaching the Earth. This energy is needed by plants for photosynthesis. However, only 1% of it is used for this, the rest is reflected or dissipated in the form of heat. This part of the spectrum has led to the appearance of many important adaptations in plant and animal organisms. In green plants, in addition to the formation of a light-absorbing pigment complex, with the help of which the process of photosynthesis is carried out, bright colors of flowers have appeared, which helps attract pollinators.

For animals, light mainly plays an informational role and is involved in the regulation of many physiological and biochemical processes. Already the simplest have photosensitive organelles (the photosensitive ocellus in green euglena), and the reaction to light is expressed in the form of phototaxis - movement towards the greatest or least illumination. Starting with the coelenterates, almost all animals develop light-sensitive organs of different structures. There are nocturnal and crepuscular animals (owls, bats, etc.), as well as animals that live in constant darkness (mole crickets, roundworms, moles, etc.).

Ultraviolet part characterized by the highest quantum energy and high photochemical activity. With the help of ultraviolet rays with a wavelength of 0.29-0.40 microns, the biosynthesis of vitamin D, retinal pigments, and skin is carried out in the body of animals. These rays are best perceived by the visual organs of many insects; in plants they have a formative effect and contribute to the synthesis of some biologically active compounds (vitamins, pigments). Rays with a wavelength of less than 0.29 microns have a detrimental effect on living things.

Intensity [show] ,

Plants, whose life activity is entirely dependent on light, develop various morphostructural and functional adaptations to the light regime of their habitats. Based on their requirements for lighting conditions, plants are divided into the following environmental groups:

1. Light-loving (heliophytes) plants open habitats that grow successfully only in conditions of full sunlight. They are characterized by a high intensity of photosynthesis. These are early spring plants of steppes and semi-deserts (goose onions, tulips), plants of treeless slopes (sage, mint, thyme), cereals, plantain, water lily, acacia, etc.
2. Shade-tolerant plants characterized by a wide ecological amplitude to the light factor. They grow best in high light conditions, but are able to adapt to varying levels of shade. These are woody (birch, oak, pine) and herbaceous (wild strawberry, violet, St. John's wort, etc.) plants.
3. Shade-loving plants (sciophytes) They do not tolerate strong lighting, they grow only in shaded areas (under the forest canopy), and never grow in open areas. In clearings with strong lighting, their growth slows down and sometimes they die. Such plants include forest grasses - ferns, mosses, wood sorrel, etc. Adaptation to shading is usually combined with the need for a good water supply.

Daily and seasonal frequency [show] .

Daily periodicity determines the processes of growth and development of plants and animals, which depend on the length of daylight hours.

The factor that regulates and controls the rhythm of the daily life of organisms is called photoperiodism. It is the most important signaling factor allowing plants and animals to “measure time” - the ratio between the duration of the period of illumination and darkness during the day, and determine the quantitative parameters of illumination. In other words, photoperiodism is the reaction of organisms to the change of day and night, which manifests itself in fluctuations in the intensity of physiological processes - growth and development. It is the length of day and night that changes very accurately and naturally throughout the year, regardless of random factors, invariably repeating from year to year, therefore organisms in the process of evolution coordinated all stages of their development with the rhythm of these time intervals.

In the temperate zone, the property of photoperiodism serves as a functional climatic factor that determines the life cycle of most species. In plants, the photoperiodic effect manifests itself in the coordination of the period of flowering and fruit ripening with the period of most active photosynthesis, in animals - in the coincidence of the time of reproduction with the period of abundance of food, in insects - in the onset of diapause and exit from it.

Biological phenomena caused by photoperiodism also include seasonal migrations (flights) of birds, the manifestation of their nesting instincts and reproduction, change of fur in mammals, etc.

According to the required length of the photoperiod, plants are divided into

• long-day plants, which require more than 12 hours of light time for normal growth and development (flax, onions, carrots, oats, henbane, dope, young, potatoes, belladonna, etc.);
• short-day plants - they need at least 12 hours of continuous darkness to bloom (dahlias, cabbage, chrysanthemums, amaranth, tobacco, corn, tomatoes, etc.);
• neutral plants in which the development of generative organs occurs both with long and short days (marigolds, grapes, phlox, lilac, buckwheat, peas, knotweed, etc.)

Long-day plants come mainly from northern latitudes, while short-day plants come from southern latitudes. In the tropical zone, where the length of day and night varies little throughout the year, photoperiod cannot serve as a guiding factor for the periodicity of biological processes. It is replaced by alternating dry and wet seasons. Long-day species manage to produce crops even in the short northern summer. The formation of a large mass of organic substances occurs in the summer during a fairly long daylight hours, which at the latitude of Moscow can reach 17 hours, and at the latitude of Arkhangelsk - more than 20 hours a day.

The length of the day also significantly affects the behavior of animals. With the onset of spring days, the duration of which progressively increases, birds develop nesting instincts, they return from warm regions (although the air temperature may still be unfavorable), and begin laying eggs; Warm-blooded animals shed.

The reduction in day length in autumn causes opposite seasonal phenomena: birds fly away, some animals hibernate, others grow dense fur, and wintering stages of insects form (despite the still favorable temperature and abundance of food). In this case, a decrease in day length signals living organisms about the imminent onset of the winter period, and they can prepare for it in advance.

In animals, especially arthropods, growth and development also depend on the length of daylight hours. For example, cabbage whites and birch moths develop normally only with long daylight hours, while silkworm, various types of locusts, scoop - in short. Photoperiodism also affects the timing of the onset and termination of the mating season in birds, mammals and other animals; on reproduction, embryonic development of amphibians, reptiles, birds and mammals;

Seasonal and daily changes in illumination are the most accurate clocks, the course of which is clearly regular and has remained virtually unchanged during the last period of evolution.

Thanks to this, it became possible to artificially regulate the development of animals and plants. For example, providing plants in greenhouses, greenhouses or hotbeds with 12-15 hours of daylight allows even in winter to grow vegetables and ornamental plants, and to accelerate the growth and development of seedlings. Conversely, shading plants in the summer speeds up the appearance of flowers or seeds on late-blooming fall plants.

By extending the day due to artificial lighting in winter, you can increase the egg-laying period of chickens, geese, and ducks, and regulate the reproduction of fur-bearing animals on fur farms. The light factor also plays a huge role in other life processes of animals. First of all, it is a necessary condition for vision, their visual orientation in space as a result of the perception by the organs of vision of direct, scattered or reflected light rays from surrounding objects. Polarized light, the ability to distinguish colors, navigate by astronomical light sources, the autumn and spring migrations of birds, and the navigation abilities of other animals are highly informative for most animals.

Based on photoperiodism, plants and animals in the process of evolution have developed specific annual cycles of periods of growth, reproduction, and preparation for winter, which are called annual or seasonal rhythms. These rhythms manifest themselves in changes in the intensity of the nature of biological processes and are repeated at annual intervals. The coincidence of the periods of the life cycle with the corresponding time of year is of great importance for the existence of the species. Seasonal rhythms provide plants and animals with the most favorable conditions for growth and development.

Moreover, the physiological processes of plants and animals are strictly dependent on the daily rhythm, which is expressed by certain biological rhythms. Consequently, biological rhythms are periodically repeating changes in the intensity and nature of biological processes and phenomena. In plants, biological rhythms are manifested in the daily movement of leaves, petals, changes in photosynthesis, in animals - in temperature fluctuations, changes in the secretion of hormones, the rate of cell division, etc. In humans, daily fluctuations in respiratory rate, pulse, blood pressure, wakefulness and sleep, etc. Biological rhythms are hereditarily fixed reactions, therefore knowledge of their mechanisms is important when organizing human work and rest.

Temperature

One of the most important abiotic factors on which the existence, development and distribution of organisms on Earth largely depends [show] .

The upper temperature limit of life on Earth is probably 50-60°C. At such temperatures, loss of enzyme activity and protein coagulation occurs. However, the general temperature range of active life on the planet is much wider and is limited to the following limits (Table 1)

Table 1. Temperature range of active life on the planet, °C

Among the organisms that can exist at very high temperatures, thermophilic algae are known, which can live in hot springs at 70-80°C. Scale lichens, seeds and vegetative organs desert plants (saxaul, camel thorn, tulips) located in the upper layer of hot soil.

There are many species of animals and plants that can withstand high sub-zero temperatures. Trees and shrubs in Yakutia do not freeze at minus 68°C. Penguins live in Antarctica at minus 70°C, and polar bears, arctic foxes, and polar owls live in the Arctic. Polar waters with temperatures from 0 to -2°C are inhabited by a variety of flora and fauna - microalgae, invertebrates, fish, whose life cycle constantly occurs in such temperature conditions.

The importance of temperature lies primarily in its direct influence on the speed and nature of metabolic reactions in organisms. Since daily and seasonal temperature fluctuations increase with distance from the equator, plants and animals, adapting to them, exhibit different needs for heat.

Adaptation methods

• Migration is relocation to more favorable conditions. Whales, many species of birds, fish, insects and other animals migrate regularly throughout the year.
• Numbness is a state of complete immobility, a sharp decrease in vital activity, and cessation of nutrition. It is observed in insects, fish, amphibians, and mammals when the environmental temperature decreases in autumn, winter (hibernation) or when it increases in the summer in deserts (summer hibernation).
• Anabiosis is a state of sharp inhibition of life processes, when visible manifestations of life temporarily cease. This phenomenon is reversible. It is observed in microbes, plants, and lower animals. The seeds of some plants can remain in suspended animation for up to 50 years. Microbes in a state of suspended animation form spores, protozoa form cysts.

Many plants and animals, with appropriate preparation, successfully tolerate extremely low temperatures in a state of deep dormancy or suspended animation. In laboratory experiments, seeds, pollen, plant spores, nematodes, rotifers, cysts of protozoa and other organisms, sperm after dehydration or placement in solutions of special protective substances - cryoprotectants - tolerate temperatures close to absolute zero.

Currently, progress has been made in practical use substances with cryoprotective properties (glycerin, polyethylene oxide, dimethyl sulfoxide, sucrose, mannitol, etc.) in biology, agriculture, medicine. Cryoprotectant solutions provide long-term storage of canned blood, sperm for artificial insemination of farm animals, and some organs and tissues for transplantation; protection of plants from winter frosts, early spring frosts, etc. These problems fall within the competence of cryobiology and cryomedicine and are solved by many scientific institutions.

• Thermoregulation. In the process of evolution, plants and animals have developed various mechanisms of thermoregulation:

1. in plants
   • physiological - the accumulation of sugar in cells, due to which the concentration of cell sap increases and the water content of cells decreases, which contributes to the frost resistance of plants. For example, in dwarf birch and juniper, the upper branches die at excessively low temperatures, while the creeping ones overwinter under the snow and do not die.
   • physical
     1. stomatal transpiration - removing excess heat and preventing burns by removing water (evaporation) from the plant body
     2. morphological - aimed at preventing overheating: dense leaf pubescence for dispersal sun rays, glossy surface to reflect them, reducing the surface absorbing rays - rolling the leaf blade into a tube (feather grass, fescue), placing the leaf edge-on to the sun's rays (eucalyptus), reducing foliage (saxaul, cactus); aimed at preventing freezing: special forms of growth - dwarfism, the formation of creeping forms (wintering under snow), dark coloring (helps to better absorb heat rays and warm up under the snow)
2. in animals
   • cold-blooded (poikilothermic, ectothermic) [invertebrates, fish, amphibians and reptiles] - regulation of body temperature is carried out passively by increasing muscle work, the structure and color of the integument, finding places where intense absorption of sunlight is possible, etc., etc. .To. they cannot maintain the temperature regime of metabolic processes and their activity depends mainly on heat coming from outside, and body temperature - on the values ​​of ambient temperature and energy balance (the ratio of absorption and release of radiant energy).
   • warm-blooded (homeothermic, endothermic) [birds and mammals] - capable of maintaining a constant body temperature regardless of the temperature of the environment. This property makes it possible for many species of animals to live and reproduce at temperatures below zero (reindeer, polar bear, pinnipeds, penguins). In the process of evolution, they have developed two thermoregulation mechanisms, with the help of which they maintain a constant body temperature: chemical and physical. [show] .
     • The chemical mechanism of thermoregulation is ensured by the speed and intensity of redox reactions and is controlled reflexively by the central nervous system. An important role in increasing the efficiency of the chemical mechanism of thermoregulation was played by such aromorphoses as the appearance of a four-chambered heart and the improvement of the respiratory system in birds and mammals.
     • The physical mechanism of thermoregulation is ensured by the appearance of heat-insulating covers (feathers, fur, subcutaneous fat), sweat glands, respiratory organs, as well as the development of nervous mechanisms for regulating blood circulation.

     A special case of homeothermy is heterothermy - different levels of body temperature depending on the functional activity of the body. Heterothermy is characteristic of animals that fall into hibernation or temporary torpor during unfavorable periods of the year. At the same time, their high body temperature is noticeably reduced due to slow metabolism (gophers, hedgehogs, bats, swift chicks, etc.).

Endurance limits large values ​​of the temperature factor are different in both poikilothermic and homeothermic organisms.

Eurythermic species are able to tolerate temperature fluctuations over a wide range.

Stenothermic organisms live in conditions of narrow temperature limits, being divided into heat-loving stenothermic species (orchids, tea bush, coffee, corals, jellyfish, etc.) and cold-loving ones (elfin cedar, pre-glacial and tundra vegetation, fish of the polar basins, abyssal animals - the areas of greatest ocean depths, etc.).

For each organism or group of individuals there is an optimal temperature zone within which activity is particularly well expressed. Above this zone is a zone of temporary thermal torpor, and even higher is a zone of prolonged inactivity or summer hibernation, bordering on a zone of high lethal temperature. When the latter decreases below the optimum, there is a zone of cold torpor, hibernation and lethal low temperature.

The distribution of individuals in the population, depending on changes in the temperature factor throughout the territory, generally obeys the same pattern. The zone of optimal temperatures corresponds to the highest population density, and on both sides of it there is a decrease in density up to the boundary of the range, where it is lowest.

The temperature factor over a large area of ​​the Earth is subject to pronounced daily and seasonal fluctuations, which in turn determines the corresponding rhythm of biological phenomena in nature. Depending on the provision of thermal energy in symmetrical areas of both hemispheres of the globe, starting from the equator, the following climatic zones are distinguished:

1. tropical zone. The minimum average annual temperature exceeds 16° C, on the coolest days it does not fall below 0° C. Temperature fluctuations over time are insignificant, the amplitude does not exceed 5° C. Vegetation is year-round.
2. Subtropical zone. The average temperature of the coldest month is not lower than 4° C, and the warmest is above 20° C. Sub-zero temperatures are rare. There is no stable snow cover in winter. The growing season lasts 9-11 months.
3. Temperate zone. The summer growing season and winter period plant dormancy. In the main part of the zone there is stable snow cover. Frosts are typical in spring and autumn. Sometimes this zone is divided into two: moderately warm and moderately cold, which are characterized by four seasons.
4. Cold zone. The average annual temperature is below O° C, frosts are possible even during a short (2-3 months) growing season. The annual temperature fluctuation is very large.

The pattern of vertical distribution of vegetation, soils, and fauna in mountainous areas is also mainly determined by the temperature factor. In the mountains of the Caucasus, India, and Africa, four or five plant belts can be distinguished, the sequence of which from bottom to top corresponds to the sequence of latitudinal zones from the equator to the pole at the same altitude.

Humidity

An environmental factor characterized by the water content in the air, soil, and living organisms. In nature, there is a daily rhythm of humidity: it increases at night and decreases during the day. Together with temperature and light, humidity plays an important role in regulating the activity of living organisms. The source of water for plants and animals is mainly precipitation and groundwater, as well as dew and fog.

Moisture is a necessary condition for the existence of all living organisms on Earth. Life originated in the aquatic environment. Land dwellers are still dependent on water. For many species of animals and plants, water continues to be a habitat. The importance of water in life processes is determined by the fact that it is the main environment in the cell where metabolic processes take place and is the most important initial, intermediate and final product of biochemical transformations. The importance of water is also determined by its quantitative content. Living organisms consist of at least 3/4 water.

In relation to water, higher plants are divided into

• hydrophytes - aquatic plants (water lily, arrowhead, duckweed);
• hygrophytes - inhabitants of excessively moist places (calamus, watch);
• mesophytes - plants with normal humidity conditions (lily of the valley, valerian, lupine);
• xerophytes - plants living in conditions of constant or seasonal moisture deficiency (saxaul, camel thorn, ephedra) and their varieties - succulents (cacti, euphorbia).

Adaptations to living in dehydrated environments and environments with periodic lack of moisture An important feature of the main climatic factors (light, temperature, humidity) is their natural variability during the annual cycle and even daily, as well as depending on geographic zonation. In this regard, adaptations of living organisms also have a regular and seasonal nature. Adaptation of organisms to environmental conditions can be rapid and reversible or quite slow, depending on the depth of exposure to the factor. As a result of their vital activity, organisms are able to change abiotic living conditions. For example, plants of the lower tier find themselves in conditions of less light; the processes of decomposition of organic substances that occur in bodies of water often cause oxygen deficiency for other organisms. Due to the activity of aquatic organisms, temperature and water regimes, the amount of oxygen, carbon dioxide, pH of the environment, the spectral composition of light, etc. change. Air environment and its gas composition The development of the air environment by organisms began after they reached land. Life in the air required specific adaptations and a high level of organization of plants and animals. Low density and water content, high oxygen content, ease of movement of air masses, sudden changes in temperature, etc. significantly affected the breathing process, water exchange and movement of living beings. The vast majority of terrestrial animals have acquired the ability to fly during evolution (75% of all species of terrestrial animals). Many species are characterized by ansmochoria - dispersal with the help of air currents (spores, seeds, fruits, protozoan cysts, insects, spiders, etc.). Some plants have become wind pollinated. For the successful existence of organisms, not only physical but also chemical properties air, its content of gas components necessary for life. Oxygen. For the vast majority of living organisms, oxygen is vital. In an oxygen-free environment, only anaerobic bacteria can grow. Oxygen ensures the implementation of exothermic reactions, during which the energy necessary for the life of organisms is released. It is the final electron acceptor, which is split off from the hydrogen atom in the process of energy exchange. In a chemically bound state, oxygen is part of many very important organic and mineral compounds of living organisms. Its role as an oxidizing agent in the cycle of individual elements of the biosphere is enormous. The only producers of free oxygen on Earth are green plants, which form it during photosynthesis. A certain amount of oxygen is formed as a result of photolysis of water vapor by ultraviolet rays outside the ozone layer. The absorption of oxygen by organisms from the external environment occurs over the entire surface of the body (protozoa, worms) or through special respiratory organs: trachea (insects), gills (fish), lungs (vertebrates). Oxygen is chemically bound and transported throughout the body by special blood pigments: hemoglobin (vertebrates), hemocyapin (molluscs, crustaceans). Organisms living in conditions of constant lack of oxygen have developed appropriate adaptations: increased oxygen capacity of the blood, more frequent and deeper respiratory movements, large lung volume (in highland dwellers, birds) or a decrease in the use of oxygen by tissues due to an increase in the amount of myoglobin - an oxygen accumulator in the tissues (in inhabitants of the aquatic environment). Due to the high solubility of CO 2 and O 2 in water, their relative content here is higher (2-3 times) than in the air (Fig. 1). This circumstance is very important for hydrobionics, which use either dissolved oxygen for respiration or CO 2 for photosynthesis (aquatic phototrophs). Carbon dioxide. The normal amount of this gas in the air is small - 0.03% (by volume) or 0.57 mg/l. As a result, even small fluctuations in the CO 2 content are significantly reflected in the process of photosynthesis, which directly depends on it. The main sources of CO 2 entering the atmosphere are the respiration of animals and plants, combustion processes, volcanic eruptions, the activity of soil microorganisms and fungi, industrial enterprises and transport. Having the property of absorption in the infrared region of the spectrum, carbon dioxide affects the optical parameters and temperature regime of the atmosphere, causing the well-known “greenhouse effect”. An important environmental aspect is the increase in solubility of oxygen and carbon dioxide in water as its temperature decreases. That is why the fauna of water basins of polar and subpolar latitudes is very abundant and diverse, mainly due to the increased concentration of oxygen in cold water. The dissolution of oxygen in water, like any other gas, obeys Henry's law: it is inversely proportional to temperature and stops when the boiling point is reached. In the warm waters of tropical pools, a reduced concentration of dissolved oxygen limits respiration, and therefore the vital activity and number of aquatic animals. Recently, there has been a noticeable deterioration in the oxygen regime of many water bodies, caused by an increase in the amount of organic pollutants, the destruction of which requires large amounts of oxygen. Zoning of distribution of living organisms Geographical (latitudinal) zoning In the latitudinal direction from north to south, the following natural zones are successively located on the territory of the Russian Federation: tundra, taiga, deciduous forest, steppe, desert. Among the climate elements that determine the zonality of the distribution and distribution of organisms, the leading role is played by abiotic factors - temperature, humidity, light conditions. The most noticeable zonal changes are manifested in the nature of vegetation - the leading component of the biocenosis. This, in turn, is accompanied by changes in the composition of animals - consumers and destructors of organic residues in food chains. Tundra- a cold, treeless plain of the northern hemisphere. Its climatic conditions are unsuitable for plant growth and decomposition of organic residues (permafrost, relatively low temperatures even in summer, short periods of above-zero temperatures). Here, unique biocenoses, small in species composition (mosses, lichens), were formed. In this regard, the productivity of the tundra biocenosis is low: 5-15 c/ha of organic matter per year. Zone taiga characterized by relatively favorable soil and climatic conditions, especially for coniferous species. Rich and highly productive biocenoses have formed here. The annual formation of organic matter is 15-50 c/ha. Temperate zone conditions led to the formation of complex biocenoses deciduous forests with the highest biological productivity in the Russian Federation (up to 60 c/ha per year). Varieties of deciduous forests are oak forests, beech-maple forests, mixed forests, etc. Such forests are characterized by well-developed shrub and herbaceous undergrowth, which facilitates the placement of fauna of various types and numbers. Steppes- a natural zone of the temperate zone of the Earth’s hemispheres, which is characterized by insufficient water supply, so herbaceous, mainly cereal vegetation (feather grass, fescue, etc.) predominates here. The fauna is diverse and rich (fox, hare, hamster, mice, many birds, especially migratory ones). The steppe zone contains the most important areas of grain production, technical, vegetable crops and livestock farming. The biological productivity of this natural zone is relatively high (up to 50 c/ha per year). Deserts predominate in Central Asia. Due to low precipitation and high temperatures in summer, vegetation occupies less than half of the territory of this zone and has specific adaptations to dry conditions. The fauna is diverse, its biological features have been considered before. The annual formation of organic matter in the desert zone does not exceed 5 c/ha (Fig. 107). Salinity of the environment Salinity of the aquatic environment characterized by the content of soluble salts in it. Fresh water contains 0.5-1.0 g/l, and sea water contains 10-50 g/l of salts. The salinity of the aquatic environment is important for its inhabitants. There are animals adapted to live only in fresh water (cyprinids) or only in sea water (herrings). In some fish, individual stages of individual development take place at different water salinities, for example, the common eel lives in fresh water bodies and migrates to the Sargasso Sea to spawn. Such aquatic inhabitants require appropriate regulation of the salt balance in the body. Mechanisms of regulation of the ionic composition of organisms. Land animals are forced to regulate the salt composition of their liquid tissues to maintain the internal environment in a constant or almost constant chemically unchanged ionic state. The main way to maintain salt balance in aquatic organisms and land plants is to avoid habitats with unsuitable salinity. Such mechanisms must work especially intensely and accurately in migratory fish (salmon, chum salmon, pink salmon, eel, sturgeon), which periodically move from sea water to fresh water or vice versa. Osmotic regulation occurs most simply in fresh water. It is known that in the latter the concentration of ions is much lower than in liquid tissues. According to the laws of osmosis, the external environment enters the cells along a concentration gradient through semi-permeable membranes, and a kind of “dilution” of the internal contents occurs. If such a process were not controlled, the body could swell and die. However, freshwater organisms have organs that remove excess water. The preservation of ions necessary for life is facilitated by the fact that the urine of such organisms is quite dilute (Fig. 2, a). The separation of such a dilute solution from the internal fluids probably requires the active chemical work of specialized cells or organs (kidneys) and their consumption of a significant proportion of the total basal metabolic energy. On the contrary, marine animals and fish drink and absorb only sea water, thereby replenishing its constant release from the body into the external environment, which is characterized by a high osmotic potential. In this case, monovalent ions of salt water are actively removed outward by the gills, and divalent ions by the kidneys (Fig. 2, b). Cells spend quite a lot of energy pumping out excess water, so when salinity increases and water in the body decreases, organisms usually switch to an inactive state - salt anabiosis. This is typical for species living in periodically drying pools of sea water, estuaries, and littoral zones (rotifers, amphipods, flagellates, etc.) Salinity of the upper crust is determined by the content of potassium and sodium ions in it, and, like the salinity of the aquatic environment, is important for its inhabitants and, first of all, plants that have the appropriate adaptation to it. This factor is not accidental for plants; it accompanies them during the evolutionary process. The so-called saline vegetation (solyanka, licorice, etc.) is confined to soils with a high content of potassium and sodium. The top layer of the earth's crust is soil. In addition to soil salinity, other indicators are distinguished: acidity, hydrothermal regime, soil aeration, etc. Together with the relief, these properties of the earth's surface, called edaphic environmental factors, have an ecological impact on its inhabitants. Edaphic environmental factors Properties of the earth's surface that have an environmental impact on its inhabitants. borrowed Soil profile The type of soil is determined by its composition and color. A - Tundra soil has a dark, peaty surface. B - Desert soil is light, coarse-grained and poor in organic matter Chestnut soil (C) and chernozem (D) are humus-rich meadow soils typical of the Eurasian steppes and North American prairies. The reddish leached latosol (E) of the tropical savannah has a very thin but humus-rich layer. Podzolic soils are typical for northern latitudes, where there is a large amount of precipitation and very little evaporation. They include organic-rich brown forest podzol (F), gray-brown podzol (H), and gray-stony podzol (I), which supports both coniferous and deciduous trees. All of them are relatively acidic, and in contrast, the red-yellow podzol (G) of pine forests is quite strongly leached. Depending on edaphic factors, a number of ecological groups of plants can be distinguished. Based on the reaction to the acidity of the soil solution, they are distinguished: acidophilic species growing at a pH below 6.5 (peat bog plants, horsetail, pine, fir, fern); neutrophils, preferring soil with a neutral reaction (pH 7) (most cultivated plants); basophila - plants that grow best on a substrate that has an alkaline reaction (pH more than 7) (spruce, hornbeam, thuja) and indifferent - can grow on soils with different pH values. In relation to the chemical composition of the soil, plants are divided into oligotrophic, undemanding to the amount of nutrients; mesotrophic, requiring a moderate amount of minerals in the soil (herbaceous perennials, spruce), mesotrophic, requiring a large amount of available ash elements (oak, fruit). In relation to individual batteries species that are especially demanding of high nitrogen content in the soil are called nitrophils (nettle, barnyard plants); those that require a lot of calcium - calciphiles (beech, larch, reznik, cotton, olive); plants of saline soils are called halophytes (solyanka, sarsazan); some of the halophytes are able to secrete excess salts outside, where these salts, after drying, form hard films or crystalline accumulations In relation to the mechanical composition loose sand plants - psammophytes (saxaul, sand acacia) plants of rocky screes, cracks and depressions of rocks and other similar habitats - lithophytes [petrophytes] (juniper, sessile oak) The terrain and the nature of the soil significantly influence the specific movement of animals and the distribution of species whose life activities are temporarily or permanently associated with the soil. The nature of the root system (deep, surface) and the lifestyle of the soil fauna depend on the hydrothermal regime of soils, their aeration, mechanical and chemical composition. The chemical composition of the soil and the diversity of its inhabitants affect its fertility. The most fertile are chernozem soils rich in humus. As an abiotic factor, relief influences the distribution of climatic factors and, thus, the formation of the corresponding flora and fauna. For example, on the southern slopes of hills or mountains there is always a higher temperature, better illumination and, accordingly, less humidity.

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Ministry of Education and Science of the Russian Federation

Federal State Budgetary Educational Institution of Higher Professional Education

"KUBAN STATE UNIVERSITY"

Department of Geoecology and Environmental Management

COURSE WORK

Relief as an environmental factor

Krasnodar 2012

Introduction

1. Vertical zonality

2. Ecology of high mountain organisms

3. The influence of exposure and slope steepness on organisms

5. Types of altitudinal zones of the Western Caucasus

6. Characteristics of organisms of the alpine and subalpine belt of the northwestern part of the Greater Caucasus

Conclusion

Introduction

The steepness of the slope and the features of its surface can affect the development of plant root systems, their external structure: in mountainous conditions, a number of tree species acquire low stature, creeping (so-called dwarf) forms. Relief influences the processes of soil formation, and soils on slopes are especially vulnerable and the destruction of vegetation (for example, during logging) and increased grazing by livestock cause soil destruction (erosion).

The main goal course work is to consider the relief as an environmental factor. The main objectives of the course work are to consider vertical zonality; study the ecology of high-mountain organisms, the influence of exposure and slope steepness on organisms; consider the role of mesorelief and microrelief elements in the life of organisms, study the types of altitudinal zones of the Western Caucasus; characterize the organisms of the alpine and subalpine zone of the northwestern part of the Greater Caucasus.

The work consists of an introduction, six chapters, a conclusion and a list of references, including 10 titles, and contains 5 figures.

1 . Vertical zonality

Relief does not belong to such direct environmental factors as water, light, heat, soil. But the nature of the relief, the location of the plant or plant community in it have a great influence on the life of the plant, since the relief often determines a combination of direct factors and redistributes in space those amounts of heat, light, moisture that are zonal, i.e. depend on the latitudinal position of the area . Thus, relief in the life of plants acts as an indirectly acting factor.

Depending on the size of the forms, relief of several orders is distinguished: macrorelief (mountains, lowlands, intermountain depressions), mesorelief (hills, ravines, ridges, karst sinkholes, steppe “saucers”) and microrelief (small westerlies, irregularities, tree-trunk elevations). This division is arbitrary, since there are no exact quantitative boundaries between the forms. Each of them plays its role in the formation of a complex of environmental factors for plants. The main structural unit of biotic cover in the mountains is the altitudinal zone [Goryshina, 1979, p. 208].

Plants are good indicators of environmental conditions and often make it possible to determine the ecological potential of a mountain area in a more general sense, since other natural components (climatic parameters, soil characteristics) can only be studied in limited areas. Therefore, physiognomically, altitudinal zones are most often distinguished by the leading type of vegetation. A vegetation belt is considered as a complex combination of climatically determined plant communities belonging to one or several types of vegetation within a certain altitudinal level, interconnected in ecological and dynamic series (phytocatenas) on slopes of different exposures.

The severity of vegetation belts in space and their length in height are often determined historical reasons, but are supported by modern local natural conditions. The contrast of vegetation on slopes of different exposures is characteristic of mountains with a drier climate. Asymmetry is observed both in relation to the set of belts and their altitudinal occurrence: within one altitudinal level there is great diversity in vegetation cover.

The length of the belt depends on many reasons, including geographic latitude, the rapidity of vertical changes in climatic conditions and the ecological amplitude of the plants forming the belt. The boundaries of the belts sometimes vary greatly in height, especially large deviations can be in various parts belt or on slopes of different exposures, where the difference in the position of the belt boundary can reach 100 m or more. The boundaries of the belts can be quite clear, as, for example, when broad-leaved forests are replaced by dark coniferous ones, but more often some transitional stripes are observed. Thus, at the upper border of dark coniferous forests in Altai with the transition to high-mountain belts, a gradual replacement of closed forests with forests with sparse stands and subalpine species in the shrub and grass cover, then open forests and open spaces with areas of subalpine meadows and, finally, individual groups of trees and single trees among subalpine meadows and thickets of subalpine bushes. This transitional band is often called the upper forest limit ecotone.

The altitude limits of the belts depend not only on the absolute height of the terrain and geographical location. Peculiarities of relief, lithology of rocks, and morphology of slopes often play a decisive role in the formation of the structure of mountain vegetation. Their animal population is closely related to the vegetation cover of high-altitude zones. In modern biogeographical literature, the altitudinal belt is considered as a complex biogeographical phenomenon, determined by the geographical position of a mountainous country and the absolute height of the area [Abdurakhmanov, 2008, p. 306-307].

2 Ecology of high mountain organisms

Macrorelief influences the distribution of vegetation types on large geographic scales, as exemplified by the phenomenon of vertical zonation in mountains. An increase in terrain level for every 100 m is accompanied by a decrease in air temperature by approximately 0.5°C. Air humidity and insolation also change. In the mountains there is a zonal distribution of climate and vegetation, to a certain extent similar to the latitudinal-zonal one (Figure 1). At the foot, vegetation types characteristic of a given geographical zone dominate; higher up they are successively replaced by more cold-resistant ones (Figure 2) [Goryshina, 1979, p. 208].

Figure 1 - Correlation between vertical and latitudinal zonality on the North American continent [Goryshina, 1979, p. 209]

1-2a - forests of the lower mountain belt with deciduous undergrowth (with a predominance of: 1 - Georgian oak, 2 and 2a - Caucasian hornbeam), 3 - mixed forests with evergreen undergrowth. 4-6 - beech forests of the middle and upper mountain zone (different types), 7-10 - beech-hemnoconiferous and dark coniferous forests (different types), 11 - high-mountain meadows and rocky vegetation, 12 - limestone border

Figure 2 - Scheme of vertical zonation of vegetation in the Caucasus (Western Georgia, Gagrin-Bzyb region) [According to Sokhadze, 1964, p. 209]

In the mountains at high altitudes, a very unique set of ecological conditions is created for plants; they are often called “alpine” regardless of geographical location.

The influx of solar radiation in the mountains is increased partly due to some rarefaction of the atmosphere, but mainly due to its greater transparency. In the highlands of the Pamirs, daytime illumination is about 130 thousand lux, i.e., only slightly less than at the boundary of the earth’s atmosphere. Ultraviolet radiation here is much stronger than on the plains: for example, at altitudes of 2500 - 4000 m, the intensity of radiation in the region of 290-310 nm (at the limit of visible light) is tens of times greater than at sea level [Goryshina, 1979, p. 208].

Other characteristic features of high-mountain conditions are low temperatures, in particular, precise frosts that affect plants in some mountainous areas during most or even the entire growing season, strong winds, and a significantly shortened growing season. At high altitudes, the carbon dioxide content in the air is reduced. For example, in the Pamirs at an altitude of 3800 m, the CO 2 concentration is only 0.012-0.020%.

As for the moisture regime in the highlands, it develops differently depending on the general climatic background of the area: there are mountainous areas of a humid nature (the Alps, the Western Caucasus, the Carpathians) and highlands where plants live in very dry conditions (regions of “cold deserts” in the Pamir, Tien Shan and other Asian mountain ranges).

Particularly peculiar are the conditions in the nival (snow) belt, in the immediate vicinity of masses of snow and ice, near the border of eternal snow, melting glaciers and snowfields.

In general, alpine conditions represent an example of “extreme” conditions for plant life (at the upper limit of the distribution of vegetation, this expression has not only an ecological, but also a direct - spatial meaning). They are reflected in all aspects of plant life - structure, physiology, seasonal development.

Alpine plants are characterized by squat growth. In all high-mountainous regions of the globe, low-growing creeping shrubs and dwarf shrubs, cushion-shaped and rosette perennial grasses, turf grasses and sedges, mosses and lichens predominate. However, there are also larger, very peculiar forms, for example, common in the highlands South America(Andes) and Africa are tree-like rosette plants from the genera Senecio, Espeletia, Lobelia with a high columnar stem bearing at the top a large rosette of fleshy, often heavily pubescent leaves [Goryshina, 1979, p. 2010].

A characteristic morphological feature of many high-altitude squat plants (shrubs, dwarf shrubs) is a significant predominance of underground mass compared to above-ground mass.

The short stature of high-mountain plants is apparently associated both with adaptation to low temperatures and with the form-building effect of radiation, rich in the short-wave part of the spectrum, which inhibits growth processes. At the end of the last century, the classical experiments of the French botanist Bonnier showed that many plants with a “normal” growth form, having long flowering stems, acquired a rosette shape after being transplanted into the mountains.

In the anatomical structure of high-mountain plants there are a number of features that partly contribute to protection from excess radiation, and are partly related to the peculiarities of the water regime and some aspects of metabolism in the highlands: thickening of integumentary tissues, pubescence, increased development of mechanical tissues that impart resistance to strong winds. However, in the mountains, plants with leaves devoid of pubescence and a waxy coating are also quite common. As the altitude of the area increases, as a rule, the cell sizes decrease and tissue density increases, the number of stomata per unit of leaf surface increases and their sizes decrease; in other words, changes towards xeromorphosis are observed. They are especially clearly expressed in plants growing on rocks. On the contrary, in species that live near melt water or other sources of moisture, the leaves are larger and the xeromorphic features are much less pronounced.

Low temperatures and strong light promote the formation of large quantities of anthocyanin, hence the deep, rich tones of flower color. The combination of large, brightly colored flowers and small leaves with small (sometimes very tiny) growth is a characteristic feature of many alpine plants.

The main physiological processes in plants in high mountain conditions are characterized by increased intensity. First of all, this relates to gas exchange. At high altitudes, very high values ​​of photosynthesis are noted (in some species up to 50-100 mg of CO 2 per 1 g of leaf per 1 hour). True, in humid highlands (Alps, Gissar Range) photosynthesis is quite moderate. However, in general, as you ascend into the mountains, there is a tendency for photosynthesis to increase. It is also noted when comparing the intensity of photosynthesis of different species in altitudinal zones [Goryshina, 1979, p. 211-212].

A characteristic feature of the physiology and biochemistry of high-mountain plants is an increase in the intensity of redox processes and an increase in the activity of the enzymes involved in them (catalase, peroxidase). Temperature optimums for their operation are lower than those of lowland plants. Many studies have noted an increase in plant respiration at high altitudes, and therefore an increase in the energy released during the breakdown of complex compounds. According to modern ideas, this is due to the fact that in difficult conditions of a mountain environment, plants develop ways of increasing the consumption of respiration energy in metabolism that do not exist on the plains. One of them is the use of energy for the synthesis of substances during the repair process.

The water regime of high-mountain plants in humid areas is quite “favorable” with the exception of arid conditions (especially in cold mountain deserts), where they are influenced by such environmental features as low availability of soil moisture due to low temperatures, and sometimes severe physical dryness of the soil in combined with the danger of high transpiration under strong lighting conditions. Therefore, with increasing altitude, changes are often observed in the main indicators of the water regime of plants: a decrease in the total water content of tissues with an increase in the proportion of bound water, an increase in osmotic pressure and water-holding capacity of leaves.

A common ecological feature of various physiological processes in high-mountain plants is a decrease in temperature optimums, which is clearly noticeable when compared with the temperature adaptations of plants in low-mountain or lowland habitats.

In general, a comparison of the main physiological indicators in mountain and lowland species (and for widespread species - in the corresponding populations) shows that at high altitudes the vital activity of plants is much more intense. Obviously, the evolution of high-mountain plants went in the direction of making fullest use of all the possibilities of the short and cold growing season.

The seasonal development of plants changes significantly when climbing into the mountains. The higher you go, the later the snow melts in spring and falls earlier in autumn, the shorter the growing season, the later spring development begins and the earlier autumn comes. In the spring, going up into the mountains, you can see the seasonal development of the same species in the reverse order (for example, in the low-mountain zone - flowering, in the middle - budding, even higher - the beginning of the growing season and, finally, just emerging from under the snow). On the contrary, in the fall, when ascending the mountains, one can observe an accelerated onset of autumn phenophases (autumn coloring of foliage, leaf fall, death of above-ground parts).

Due to the short growing season in the highlands, the pace of seasonal development here is significantly accelerated. This is clearly visible in the speed of passage of phenological phases at different altitudes in the Caucasus Mountains: for example, the budding phase is reduced by 5-7 days with an increase of 100 m (at high altitudes this reduction is less), which is confirmed by experimental plant transplants to different altitudes.

Different types of plants relate differently to altitudinal zonation. Some have a wide altitudinal range and grow in different zones, but at the same time their appearance and basic aspects of life change greatly. An example is blueberries and blueberries in the Carpathians, distributed from the low-mountain to the alpine zone, and fescue in the Caucasus mountains. However, a wide altitudinal range is not always associated with great ecological plasticity of plants: for example, Korolkov’s saffron - Crocus korolkovii, found in the Tien Shan at different altitudes in all altitudinal zones, grows only soon after the snow melts, that is, under the same hydrothermal conditions, although the timing of its development and occur at different times, from January to June. This is an example of a very narrow ecological amplitude over a wide altitudinal range.

Other species are distributed within limited limits of several or one (sometimes quite narrow) altitudinal zone and disappear when moving to neighboring ones, being replaced by replacement species. Thus, in the mountains at different altitudes similar species grow - hill geranium - Geranium collinum and rock geranium - G. saxatile, which also have intraspecific altitudinal forms with morphological and biochemical differences and a narrow ecological amplitude. Sometimes a species goes beyond a certain altitudinal zone, but at the same time settles in completely different habitats [Goryshina, 1979, p. 213-216].

3. The influence of exposure and slope steepness on organisms

Along with the altitude above sea level, the conditions for plant life in the mountains are largely determined by the exposure and steepness of the slopes. It is known that on southern-facing slopes the angle of incidence of sunlight is closer to direct than on a horizontal surface (with the exception of equatorial regions) (Figure 3).

Figure 3 - Difference in the angle of incidence of sunlight on slopes of southern and northern exposure [Goryshina, 1979, p. 217]

Slopes with a northern exposure receive direct rays at very sharp angles ("sliding" rays), and with great steepness in the daytime they are content with only scattered radiation. Hence, there are significant differences in the heating of air and soil, moisture regime (in particular, the rate of snowmelt and soil drying) and other elements of the microclimate. Often, when moving from the northern slope to the southern slope, the conditions differ so sharply, as if the distance were several hundred kilometers to the south in the latitudinal direction.

Due to uneven conditions on slopes of different exposures, the composition of vegetation, the appearance and condition of plants differ markedly. It is known that on the southern slopes the tree line rises much higher than on the northern ones. In general, the boundaries of all zones shift upward, and more southern and heat-loving elements predominate in the composition of plant groups.

The morphophysiological characteristics of plants of the same species also differ depending on the exposure. Thus, the Turkestan juniper juniper (Juniperus turkestanica) in the subalpine zone of the mountains of Kyrgyzstan usually has an elfin form (at the age of 300-500 years, the length of the trunks is only 2-3 m), but near the rocks of southern exposure it grows in the form of tall slender trees, since here it is provided protection from winter drying and freezing. Comparative study. beech trees on the slopes of northern and southern exposure in the Italian Alps showed that on the northern slopes the structure of the leaves is generally characterized by more “shady” features, and the water regime is more hygrophilic (lower transpiration, higher water content of the leaves). However, under more intense conditions of water supply and temperature, other relationships may occur: for example, plants of cereal-forb meadows of the Caucasus transpirate more on the northern slopes. The influence of different exposures is reflected in the composition of vegetation not only in the case of large relief elements; it is clearly visible on small hills, elevations, and boulders [Goryshina, 1979].

The influence of slope steepness on the living conditions of plants is reflected mainly through the characteristics of the soil environment, water and temperature conditions. Strong water runoff and soil washout from steep slopes create difficult conditions for plant growth. The advantage here is that of lithophilic species with a deep and tenacious root system that uses water sparingly. On slopes with softer soil (for example, steep walls of deep ravines), pioneer plants with a shallow and branched root system are well established. In mountainous countries with very complex terrain, a very complex interweaving of influences is created - latitudinal factors, vertical zonality, differences in slope exposure, their steepness, degree of ruggedness, as well as features of soil conditions and water regime. Therefore, the picture of the distribution of environmental factors and vegetation can be greatly complicated. Thus, in closed basins, even at low altitudes, colder air accumulates than in the overlying belts; in such cases, inversions (reversals) of zoning are possible. For example, inversions are very obvious in the foothills of the Low Tatras in Slovakia with a complex topography in the area of ​​karst phenomena: high-mountain species descend very low here along cold and wet gorges, and many heat-loving lowland species, on the contrary, rise along well-lit and heated limestone ridges higher than their usual high altitude area.

In well-protected relief elements, extremely favorable conditions for plants can be created, conducive to the preservation of particularly heat-loving relict forms. Such, for example, are the wide crevices between the rocks above the Danube in Eastern Serbia, protected from the winds and experiencing the moisturizing effect of the river. They preserve many rare, relict and endemic forms.

4. The role of mesorelief and microrelief elements in the life of organisms

For relief forms smaller than mountains - dissected hills - the change in landscapes and, in particular, vegetation cover with height is very weakly expressed. In the forest zone, admixtures of oak and ash in tree stands are confined to elevated areas, and more northern elements settle on low-lying plains prone to swamping. Of course, what plays a role here is not so much the position above sea level itself, but rather geomorphological factors (terrain dissection) and the associated change in soil and hydrological conditions.

The main significance of mesorelief elements is the redistribution of zonal environmental factors. The combination of various mesorelief elements, sometimes very complex, can change zonal climatic and soil factors beyond recognition and lead to the settlement of completely special vegetation, as is the case, for example, in the valleys of large rivers. According to A.P. Shennikov, river valleys are like roads along which the climate of two neighboring latitudinal zones penetrates one into the other. And, on the contrary, in each zone there are habitats that are most free from the influence of relief, most fully reflecting the climate and soil characteristics characteristic of a given geographical zone. Such habitats (usually level, flat) are called upland or plakors (levels). Usually these are watershed plains with relatively homogeneous conditions or their individual sections. The influence of mesorelief on the combination of environmental factors is especially pronounced where certain factors are close to a minimum. For example, in southern regions with a dry climate, topography significantly affects the distribution of moisture for plants. The accumulation of snow and melt water in negative elements of the relief - ravines and gullies - makes it possible for gully forests to grow in the treeless steppe of the south of the European part of the USSR. On the flat plain of the forest-steppe of Western Siberia, in closed depressions of insignificant height, the soil moisture is so significant that woody vegetation can grow there in the form of forest islands - “pegs”. In the feather grass steppes of Ukraine, barely noticeable but wide depressions - “pods” - collect meltwater in the spring, which ensures a more mesophilic composition of the steppe grass stand. On the contrary, slightly elevated areas of the steppe are occupied by more xerophilic plant groups.

A very clear example of the influence of relief on a complex of environmental factors and vegetation is a comparison of overgrown ravine slopes of different exposures in the southern part of the forest-steppe zone. In the more eastern regions of the forest-steppe zone, the vegetation can almost accurately determine the exposure of the slope: the northern and northwestern ones are occupied by forests, the southern and southeastern ones are treeless, steppe.

Examples can also be given from more northern regions: in the Moscow region, when sandy slopes are overgrown, spruce and pine undergrowth, many forest grasses and mosses prefer to settle on the northern slope, on which, as a result, a richer species composition is formed.

In the northern regions, where there is little heat, the influence of mesorelief is also very great. Here, elevated relief elements (in particular, steep slopes of river valleys) are more drained and warmer, especially slopes with a southern exposure. In areas of permafrost rocks ("permafrost") on such relief elements, the soil thaws to a greater depth. In the tundra, on the slopes of southern exposure, more heat-loving shrub groups develop (Figure 4). Fragments of more southern types of vegetation penetrate along the slopes to the north (for example, colorfully flowering areas of meadows - tundra meadows).

Predominant species: 1 - wild rosemary, 2 - dwarf birch, 3 - dwarf willow, 4 - meadow grasses, 5 - sedges, 6 - lichens. Soils: 7 - clayey, 8 - sandy, 9 - peat

Figure 4 - The influence of relief on the distribution of vegetation in the tundra. Reindeer ridge in the Bolshezemelskaya tundra [according to Andreev, 1932, p. 222]

In addition to the difference in species composition, on slopes of different exposures there is an unequal rate of phenological development, which is especially noticeable in spring phenomena - soil thawing, shoot regrowth, bud development, and flowering. In negative relief elements, the phenological development of plants may be delayed due to the long-term preservation of snow. The patterns of influence of slopes of different exposures on the vegetation cover are well reflected in the “preliminary rule” formulated by V.V. Alekhin: “The upland species or upland vegetation is preceded in the south or north under appropriate habitat conditions,” in other words, the vegetation of the southern slopes on some or the territory contains elements of more southern upland areas, and the vegetation of the northern slopes contains elements of more northern upland areas. This rule is applicable for many southern forest-steppe and steppe regions, where the soils are well drained, but in other areas it is violated by such phenomena as waterlogging (in the north) or salinization (in the south).

Microrelief can be associated both with unevenness of the soil surface and with the growth characteristics of the plants themselves (the formation of tussocks by large-turf grasses and sedges, near-trunk elevations in the forest). Some forms of microrelief are of zoogenic origin (discharges of earthmovers - molehills, marmots).

Microrelief contributes to the manifestation of differences in the habitat of plants, insignificant in spatial extent, but quite clearly expressed in the nature of the action of environmental factors. Therefore, the microstructure of the vegetation cover often depends on the microrelief - the alternation of species with different ecological characteristics in a small space. Examples - ridge-hollow complex in swamps (a combination of more xerophilic and extremely hygrophilic elements); mosaic vegetation of hummocky meadow; complex semi-desert in the Caspian region, depending on small differences in microrelief - a combination of small patches of chernozem soils, solonetzes and clayey soils with different species composition of the vegetation cover.

The influence of microrelief is especially noticeable in extreme conditions of existence: for example, in Eastern Siberia on permafrost, the thawing of hummocks is faster than depressions; As a result, in sparse pine and larch forests, the difference in the timing of the beginning of the growing season and the flowering of wild rosemary at a distance of several meters can reach a crescent (which corresponds to several hundred kilometers in latitude).

5. Types of altitudinal zones of the Western Caucasus

The Caucasus is a mountainous country, mountain systems determine its geographical specificity and determine the exceptional diversity of natural features. Associated with the mountainous terrain is the altitudinal zonation of the landscapes of the Caucasus, the “spectrum” of which is very wide here - from subtropical landscapes in the lowlands of Transcaucasia to eternal snow and ice in the mountains. In the more northern and lower mountains there are no such large changes in natural conditions vertically: there are no subtropical and high-mountain landscape zones characteristic of the Caucasus.

The Caucasus is a complex system of high mountain ranges of alpine folding, highlands, plateaus and tectonic lowlands. The Greater Caucasus, stretching from northwest to southeast for 1100 km, is characterized by high mountains, an alpine type of relief, and there are large glaciers up to 12 km long or more.

The Caucasus is a landscape node, the intersection of two natural zones - temperate and subtropical. On its territory there are four main types of altitudinal zones: steppe temperate zone, semi-desert temperate zone, semi-desert Mediterranean and moist forest Mediterranean. The structure of altitudinal zones is in many cases complete - from zonal landscapes of lowlands to the alpine belt with eternal snow.

The Western Caucasus is the part of the Greater Caucasus west of Elbrus. The heights of the Western Caucasus do not exceed 4000 m (Dombay-Ulgen - 4046 m). According to the nature of the relief and geological structure, the Western Caucasus is divided into two sections: the North-Western, stretching from the beginning of the Greater Caucasus (the village of Gostagaevskaya) to the city of Fisht, and the Western itself - from the city of Fisht to the city of Elbrus. They are separated by the meridional Pshekhsko-Adler fault. [Efremov, 1988, p. 45]

The vegetation cover of the northwestern part of the Greater Caucasus is distinguished by its complexity and originality, which is associated with the diversity of physical and geographical conditions: the influence of relief, the proximity of the Black Sea, differences in climate and soil types, and latitude-longitude coordinates. Flora and vegetation cover have gone through a long evolutionary path of formation and decay of various types of floristic complexes. The vegetation cover reflects the history of the formation of the Caucasus as a mountainous country and the fluctuations of the Ice Age.

In the north-west of the Greater Caucasus, latitudinal zonality and vertical zonation are clearly visible. In such a small area, you can get acquainted with the Kuban steppes, which are still preserved, although in small quantities, in the Uspensky region on the spurs of the Stavropol Upland and on the Taman Peninsula, with unique floodplain ecosystems.

There is no consensus on the number of belts and criteria for their delimitation in the region. Thus, E.V. Schiffers in 1953 identified six belts in the North-West Caucasus: nival - above 3200 m above sea level; subnival - from 2800 m to 3200 m; alpine - 2200-3300 m above sea level; subalpine - 1800-2200 m; forest - from 100-300 m to 1800-2000 m; forest-steppe - 100-300 m. A.A. Kolakovsky (1961) considers seven belts on the southern macroslope: coastal vegetation belt - 100-300 m; subtropical forest - 300-600 m; beech forests - 600-1200 m; beech-fir - up to 1800-1900 m; the belt of birch forests and tall grasses occupies an altitude limit of 100-150 m; belt of subalpine or hemicryophilic mid-grass meadows and shrubs - from 1900-2000 m to 2300 m; belt of alpine (eucryophilic) short-grass meadows - up to 2600-2700 m

In the Western Caucasus, several types of zonation can be distinguished (Figure 5). First of all, this is the North Caucasian Kuban type of zonation. It is expressed on the northern macroslope.

1 - forest-steppe; 2 - oak forests; 3 - beech forests; 4 - beech-fir forests; 6 - oak forests; 7 - belt of littoral vegetation; 8 - subtropical Colchis forests; 9 - pine forests; 10 - subalpine crooked forest; 11 - subalpine meadows; 12 - alpine meadows; 13 - belt of mountain steppes.

Figure 5 - Types of vertical zonality in the northwestern part of the Greater Caucasus [Litvinskaya, 2001, p. 10]

The first zone is the lower forest-steppe - up to 500-600 m above sea level. The climate is temperate continental, the average annual precipitation is 660 mm. It has two stripes:

a) pedunculate oak forests with a significant admixture of ash, aspen, Tatarian and field maples in flat terrain in combination with true and shrub steppes on merged chernozems and dark gray mountain forest soils;

b) a strip of pedunculate oak forests with a significant participation of common hornbeam and sessile oak in the foothills at altitudes of 300-600 m above sea level on light gray mountain forest soils.

Middle forest belt of rocky oak forests in complex with hornbeam, hornbeam-beech communities. It occupies altitudes from 600 to 800 m above sea level, where brown mountain forest and brown mountain forest podzolized soils are common. The climate is temperate continental. Precipitation is 880-1000 mm per year, the average annual temperature is 7-8°C.

The upper forest belt of beech, beech-fir and fir forests ranges from 800 m to 1500-1600 m above sea level. The climate is temperate continental, the average annual precipitation is 800-1000 mm, the average annual temperature is from 5-7 ° C to 8-9 ° C, three bands are distinguished in this zone:

a) a strip of beech forests from 800 to 1200 m above sea level on brown mountain forest soils;

b) a strip of beech-fir forests from 1100 m to 1400 m above sea level. on brown mountain forest podzolized soils;

c) a strip of fir forests from 1400 m to 1800 m above sea level on brown mountain forest podzolized soils.

The belt of alpine vegetation is characterized by alternating subalpine crooked forests, thickets of Caucasian rhododendron, tall grasses, subalpine and alpine meadows. It occupies an altitude range from 1700 to 2700 m above sea level. The climate is cold and humid, the average annual precipitation is 1000-1200 mm. The belt includes three stripes:

a) a strip of subalpine beech and fir forests at an altitude of 1700-1800 m, thickets of Caucasian rhododendron on peaty soil and tall grasses;

b) a strip of subalpine meadows from 1500 to 2300 m above sea level on mountain meadow soils in combination with rock and scree vegetation; in some places subalpine communities are combined with alpine ones;

c) a strip of alpine meadows from 2300 to 2600 m above sea level in combination with alpine carpets (up to an altitude of 2400 m) of Bieberstein's bell (Campanula biebersteiniana L.), mantles (Alchemnlla xanthochlуra L.), Helen's buttercup (Ranunculus helenae Albov), sedge and cobresia alpine meadows, grass swamps (2300-2350 m), vegetation of rocks and screes.

On the southern macroslope in the southeastern part, where the Main Caucasus Range has its maximum heights in the region, the Colchis type of zonation is distinguished. It is not found anywhere else in Russia. The Colchis type begins near the Black Sea coast with a lower belt of littoral vegetation and xerophytic shrubs. It is expressed up to an altitude of 100 m above sea level and is represented by communities of littoral species of yellow poppy (Glaucium flavum L.), seaside eryngium (Eryngium maritimum L.), milkweed (Euphorbia paralias L.), thickets of xerophytic shrubs from the tree-tree (Paliurus spina -chrysti L.), Abraham tree (Vitex agnus-castus L.) and Pitsunda pine communities. The climate is humid subtropical. The average annual temperature is 14°C, the average annual precipitation is 1400 mm. The soils are sandy, pebbly, humus-carbonate on coastal cliffs, highly eroded. Lower forest belt of subtropical Colchis forests of chestnut (Castanea sativa L.), Hartwis oak (Quercus hartwissiana L.), Georgian oak (Q. iberica L.), oriental beech (Fagus orientalis L.), hornbeam, alder (Alnus barbata L.), lapina (Pterocarya pterocarpa L.), fig (Ficus carica L.), boxwood (Buxus colchica L.). The soils are alluvial, zheltozems and zheltozems-podzolic. The climate is subtropical with positive winter temperatures, high precipitation (1200-1500 mm), falling mainly during the cold period, and continuous vegetation. The belt occupies altitudes from 100 to 600 m above sea level. The middle mountain forest belt of beech forests occupies altitudes from 600 to 1200 m above sea level. It often contains chestnut forests, forests of Georgian oak (Quercus iberica L.), maples with an evergreen undergrowth of cherry laurel (Laurocerasus officinalis), holly (Ilex colchica), and Pontic rhododendron (Rhododendron ponticum). The climate is temperate continental, average annual temperature 10°C, average annual precipitation 1800 mm, brown mountain forest soils.

The upper forest belt of beech-fir forests is expressed at an altitude of 900 to 1700 m above sea level. The climate is temperate continental, the average annual temperature is 3°C. The soils are brown podzolized.

The belt of alpine vegetation is represented by a whole complex of plant formations, which are divided into three altitudinal bands:

a) a strip of birch crooked forests and tall grasses. Occupies a strip of 100-150 m above the fir-beech forests. In addition to birch forests, maple, beech and pine forests grow here. A constant component is subalpine tall grass, where giant grasses grow: telekia (Telekia speciosa), delphiniums (Delphinium speciosum, D. pyramidatum), wrestler (Aconitum orientale), hogweed (Heracleum mantegazzianum). The climate is cold and humid, the average annual temperature is 3.5°C. Characterized by heavy snow cover in winter and high air humidity.

b) a strip of subalpine meadows and bushes. The vegetation of subalpine meadows is interspersed with thickets of Caucasian rhododendron (Rhododendron caucasica), junipers (Juniperus hemisphaerica, J.sabina), heaths (Vaccinium vitis-idaea, Empetrum caucasicum), willows (Salix caprea, S. kazbekensis). The climate is humid, precipitation falls up to 2600 mm per year, snow cover is up to 6 m thick, the snow line runs at an altitude of 2650 m. The soils are brown mountain-meadow, humus-turf-meadow.

c) a strip of alpine meadows extends from 1800 m to 2100 m above sea level. Here you can see alpine carpets, short-grass meadows: cereals, sedge-cobresia, forbs and others.

On the southern macroslope in the northwestern part of the Black Sea coast of the Caucasus, the Mediterranean (Crimean) type of zonality is expressed. It is represented by completely different types of vegetation and is fundamentally different from the Colchis type. It has four belts. The lowest zone of littoral vegetation, shrub thickets of dwarf tree, leather sumac (Rhus coriaria), bladderwort (Colutea cilicica), coastal communities of Pitsunda pine (Pinus brutia pityusa). The belt occupies altitudes of up to 100 m. The climate is dry subtropical (Mediterranean). Next is the lower mountain belt of hemixerophilic forests and xerophytic woodlands. It is characterized by the dominance of fluffy oak forests, juniper forests, pistachios, forests of Pitsunda pine (Pinus brutia pityusa) and Crimean pine (Pinus pallasiana), mountain xerophytic groups. Occupies coastal ridges up to an altitude of 500 m above sea level. The climate is dry subtropical, characterized by high summer temperatures (34-40°C), the average annual temperature is about 12°C, the average annual precipitation is from 420 - 760 mm). The soils are soddy-carbonate, brown, heavily eroded. The following bands are distinguished in this belt:

a) a strip of forests of Pitsunda pine (Pinus brutia pityusa) up to an altitude of 200 m above sea level;

b) a strip of open forests of junipers (Juniperus), pistachio (Pistacia mutica Mey), forests of Crimean pine (Pinus pallasiana), tomillaria. Altitude limits of the strip - 200-400 m;

c) a strip of downy oak forests (400-500 m above sea level) in combination with junipers, Koch pine (Pinus kochiana), upland xerophytic groups, and tomillaria.

The mid-mountain belt is represented by rocky oak forests at altitudes of 400-700 m above sea level in combination with downy oak forests and hornbeam thickets. Soils are soddy-carbonate, brown forest. Post-forest meadows are common on watersheds.

The Mediterranean type of zonation ends with a belt of mountain steppes (600-900 m above sea level) of feather grass and forb communities with hemixerophilic Mediterranean elements: Thymus markhotensis, open sage (Salvia ringens), Crimean and yellow asphodelines (Asphodeline taurica, A. lutea), ironweed (Sideritis euxina), common dubrovnik (Teucrium chamaedrys).

It should be noted that this is not a typical Crimean type of zonation, since here the belt of Crimean pine is represented fragmentarily, and the belt of rocky high-mountain meadows and dwarf juniper is not expressed.

The noted patterns in the change of vegetation with height are only of a very general nature. The zonality is quite often violated, which is due not only to natural reasons (microclimatic and soil conditions, complex orography, the influence of exposure and steepness of slopes), but also to human activity. Thus, the upper limit of the forest on the Fisht-Oshtenovsky massif is significantly reduced and can be traced at an altitude of 1600-1700 m, which is not due to natural factors, but to excessive grazing and logging.

The lowest forest boundary is in the upper reaches of Belaya and Pshekha, and fir communities are already found at an altitude of 650 m, which is explained by the proximity of the Black Sea and the free penetration of humid air masses in this depression of the Main Caucasus Range. There are cases of inversion of forest belts into the area of ​​longitudinal valleys, where oak forests occupy the southern slopes up to an altitude of 1500 m above sea level, while the northern slopes are covered with fir forests. In the Laba-Belaya interfluve, the beech tree drops to 150 m above sea level. The main tracts of beech forests are concentrated in the mid-mountain zone of the northern slopes of the Front Range up to an altitude of 1400 m above sea level, but from an altitude of 700 m Nordmann fir begins to mix with the beech in the first tier, and from an altitude of 1000 m pure fir forests and fir-beech communities grow.

In the Western Caucasus there is no clear boundary between the belts of beech and fir forests, although optimal conditions for beech are at an altitude of 700-1300 m, and for fir - 1000-1600 m. On the northern spurs of the Main Range, the belt of beech forests falls out, and at altitudes of 1100-1600 m. At 1400 m mixed beech-fir communities predominate, giving way higher up the slope to pure fir forests. In the altitudinal distribution of beech, a decrease in the upper limit of pure beech forests was noted from 1400-1500 m above sea level to 1000-1100 m as it approaches the watershed ridge.

On the northern exposures of the Rocky Range, pure beech forests grow on the lower spurs, and beech-fir forests grow in the depths of the mountains. In general, it should be noted that in the Western Caucasus on the peripheral ridges there is a sharp decrease in the upper limit of the forest compared to the Main Watershed Range by 500 m [Litvinskaya, 2001, p. 10-13].

6. Characteristics of organisms of the alpine and subalpine belt of the Northwestern part of the Greater Caucasus

The altitude is 1900-2100 meters above sea level - a subalpine vegetation zone. It is a complex complex of different types of vegetation. Beyond the upper border of the forest, ending with open forests and crooked forests, the subalpine belt begins. The subalpine belt is associated with subalpine meadows, but meadows are only one of the components of the vegetation of this belt. There are also thickets of low-growing junipers, rhodoretes and subalpine tall grasses.

Rhodorets are a shrub form of the evergreen Caucasian rhododendron (Rhododendron caucasicum), a relic of the mountain tundra of the Tertiary period. Rhodorets inhabit peat soils of the subalpine zone, and often enter the alpine zone. Caucasian rhododendron (Rhododendron caucasicum) forms, although low, but impenetrable thickets. This circumstance, as well as the presence under the bushes of a thick layer of slightly decomposed peat with acidic soils, creates specific conditions that few plants can tolerate. Caucasian mountain ash (Sorbus caucasica) and willows (Salix) are occasionally visible here and there. Small shrubs from the lingonberry family are more common; the most constant companion of the Caucasian rhododendron is blueberries, blueberries and lingonberries - typically northern berries.

Junipers are scattered over gravelly slopes and scree areas over a large area, but never close together. This is a special subalpine version of rock-talus vegetation. They stand out especially clearly against the yellowish-green background of dying vegetation in early autumn. On top, the cap of junipers is dense, and inside the bushes there is a chaos of twisted stems, forming incredible weaves.

At an altitude of more than 2000 meters you will no longer find forests; here the expanse of subalpine tall grass meadows opens up. The height of flowering of subalpine meadows is mid-July. There are many in subalpine meadows rare plants. In the high-mountain flora of the northwestern Caucasus, there are 287 endemic species, and there are endemics of the Caucasus. Their origin is connected with the Main Caucasus Range. These are sulfur-yellow goose onion (Gagea), Lipsky tulip (Tulipa lipskyi Grossh), rock valerian (Valeriana saxicola), Kuban oysterwort, Oshtensk gentian (Gentiana oschtenica L.). Only from the Aster family (Asteraceae) 45 endemic species grow in the highlands. In total, one hundred representatives from the Asteraceae family were discovered and registered in these places [Litvinskaya, 1982, p. 115].

In mountainous areas, forest ecosystems are affected by a complex of factors related to relief: it influences the formation of forest conditions [Fomin, Shavnin 2002, p. 170].

Among the tree forms there are endemics. These are three species of willow - legless (Salix appendiculata L.), Caucasian (Salix caucasica L.) and silky (Salix pantosericea L.). 287 plant species grow in the highlands of the northwestern Caucasus and are not found anywhere else in the world.

Subalpine tall grass has a diverse floristic composition. Some of its representatives are tertiary relicts: species of hogweed (Heracleum), bellflower (Campanula), elecampane (Inula), telekia (Telekia) and lily (Lilium).

An altitude of 2300-2500 meters above sea level is the last outpost of grassy vegetation, the alpine belt. It extends from the subalpine to the upper reaches of mountain life. Alpine plants tend to cling as close to the ground as possible, to gather their vegetative organs more compactly into a dense bunch or pillow. Such forms were developed in a long process of evolution of many generations and became a response of plants to the constant tension of the natural conditions of the highlands. Very short growing season, only 2-2.5 months.

In the alpine there are meadows where the main builders are cereals and sedges. These are the so-called dense turf meadows. The most common representatives here are sheep and fragrant spikelet. There are many different herbs: Caucasian lyadvinets, Caucasian thyme (Thymus nummularius).

There is another type of vegetation in this belt - alpine carpets. They differ from meadows in that grasses and sedges play a secondary role in them. The process of sod formation is expressed here more by forb forms. Species such as purple dandelion and many types of cuffs grow here: reticularis, silk, silky, Caucasian.

Isolated among glacial fields, the rocks are devoid of animal populations. In tall-grass subalpine meadows, insects are represented mainly by dipterans, hymenoptera and butterflies. Locusts and beetles with strong flight, such as jumping beetles, predominate. Lepidoptera are few. Lots of spiders. The most common rodents are bush voles and Promethean voles. The abundance of midges, horseflies and mosquitoes creates difficult living conditions for ungulates here. Therefore, deer, chamois and aurochs, as a rule, leave from here either into the forest or climb to high passes. Most often, wild boars, roe deer and bears remain, creating real corridors among the tall grass.

The red deer population numbers approximately 1,000 individuals. Their range covers the territory of the Caucasus Nature Reserve.

Amphibians and reptiles are rare; only Transcaucasian and Asia Minor frogs, rock lizards (Darevskia Arribas L.), viper and copperhead are found. There are few birds, passerines predominate. Nesting birds are represented by species similar in adaptation to the inhabitants of northern meadows. The lark-like mountain pipits (Anthus L.) are characteristic, as are mountain swallows (Delichon L.), white-throated blackbirds (Turdus torquatus L.), red-bellied redstarts (Phoenicurus erythrogastrus L.) and Caucasian bee-eaters (Pinicola L.). Rodents are ubiquitous - voles, wood mice and Caucasian mice. Among the predators, wolves and foxes are present, and martens come from below [Abdurakhmanov, 2008, p. 331-332].

Conclusion

Relief is predominantly an indirect abiotic factor, since, for example, terrain elevation (height) is not an actual environmental factor. But the entire complex of microclimatic and soil factors depends on the height, the degree of steepness of the slope of a mountain or hill, the orientation of the slope relative to the cardinal points, and the general structure of the relief.

In conclusion, several conclusions can be drawn about relief as an environmental factor:

The nature of the relief, the location of the plant or plant community in it have a great influence on the life of the plant, since the relief often determines a combination of directly acting factors and redistributes in space those amounts of heat, light, moisture that are zonal, therefore the relief in the life of plants acts as an indirectly acting factor .

Macrorelief influences the distribution of vegetation types on large geographic scales, as exemplified by the phenomenon of vertical zonation in mountains.

The conditions for plant life in the mountains are largely determined by the exposure and steepness of the slopes.

The Caucasus is a landscape node, the intersection of two natural zones - temperate and subtropical. On its territory there are four main types of altitudinal zones: steppe temperate zone, semi-desert temperate zone, semi-desert Mediterranean and moist forest Mediterranean. The structure of altitudinal zones is in many cases complete - from zonal landscapes of lowlands to the alpine belt with eternal snow.

The subalpine belt is a complex complex of different types of vegetation. The subalpine belt is associated with subalpine meadows, but meadows are only one of the components of the vegetation of this belt. There are also thickets of low-growing junipers, rhodoretes and subalpine tall grasses.

In tall-grass subalpine meadows, insects are represented mainly by dipterans, hymenoptera and butterflies. Locusts and beetles with strong flight, such as jumping beetles, predominate.

List of used literature

zonality exposure mesorelief Caucasus

Abdurakhmanov G.M., Krivolutsky D.A., Myalo E.G., Ogureeva G.N. Biogeography, M.: Academy, 2008. 480 p.

Akimova T.A., Kuzmin A.P., Khaskin V.V. Ecology. M.: UNITY-DANA, 2001. 343 p.

Berezina N.A., Afanasyeva N.B. Plant ecology. M.: Academy, 2009. 400 p.

Goryshina T.K. Plant ecology, M.: Vyssh. school, 1979. 368 p.

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Climatic factors: 1) primary periodic factors (light, temperature); 2) secondary periodic factors (humidity); 3) non-periodic factors (storm winds, significant ionization of the atmosphere, fires).[...]

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Wind is an important abiotic factor that significantly shapes the living conditions of organisms, as well as affecting the formation of weather and climate. Among other things, wind is one of the very promising alternative energy sources.[...]

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Wind is the most important factor in the spread of moisture, seeds, spores, chemical impurities, etc. over long distances. It contributes both to a decrease in the near-Earth concentration of dust and gaseous substances near the point of their entry into the atmosphere, and to an increase in background concentrations in the air due to emissions from distant sources, including transboundary transfer.[...]

Wind is a powerful factor in the process of regeneration of species that have light and small seeds, ranging from birch, aspen (and other species of the poplar genus), elms, alders and ending with linden, pine and spruce, the seeds of which are carried especially far along the snow crust.[ . ..]

All factors of exogenous influence appear either at the boundary of the atmosphere and the lithosphere, or the hydrosphere and the lithosphere. In the first case, the most destructive are temperature fluctuations, precipitation, water freezing, wind, atmospheric discharges, etc., combined into a group of atmospheric agents. Their combination causes the weathering of rocks and their deflation. In the second case, destruction is carried out mainly by moving streams of water (water erosion).[...]

When the wind blows over the surface of the Earth, regardless of whether it is solid land or the surface of the sea, tension arises on it (see Chapter 2). Indeed, the main current systems of the World Ocean are predominantly of wind origin. Let us now consider this type of forcing forces. Although this is surprising, it turns out that it has properties similar to the properties of the forcing forces of topographic nature.[...]

An important factor in the change in the module and direction of wind speed with distance from the earth's surface, along with changes in turbulent viscosity, is horizontal thermal heterogeneity in layers located at different levels above the ground, i.e. 6a-rocklinity of the atmosphere. As a result, a thermal component of wind speed is formed, or, as they say, thermal wind.[...]

One of the salinity factors is wind. It captures salty dust and transports it long distances into the interior of the continents. A similar phenomenon is observed in the Aral Sea region, where the wind intensifies the removal of salts and dust from the dried seabed and their transfer to the region.[...]

The main factors causing destruction during the passage of a TC are winds reaching speeds of 100 m/s or more, waves 20-30 m high, storm surges up to 3-7 m high and floods resulting from large (up to 1300 mm/day) quantities precipitation. In addition, TCs along a coast with an inclined bottom cause so-called edge waves, propagating parallel to the coast, with a period of 5-7 hours, a length of several hundred kilometers and a height of about a meter. The combination of these phenomena determines the destructive effect of cyclones.[...]

Physical factors of the external environment (climate, weather, high and low temperatures, wind, etc.) primarily cause tension in the body’s thermoregulation system.[...]

Physical factors are those whose source is a physical state or phenomenon (mechanical, wave, etc.). For example, the temperature, if it is high, will cause a burn; if it is very low, it will cause frostbite. Other factors can also influence the effect of temperature: in water - current, on land - wind and humidity, etc. [...]

Physical factors of the air environment: movement of air masses and atmospheric pressure. The movement of air masses can be in the form of their passive movement of a convective nature or in the form of wind - due to the cyclonic activity of the Earth's atmosphere. In the first case, the dispersal of spores, pollen, seeds, microorganisms and small animals with anemochores, very small sizes, parachute-like appendages, etc. is ensured. In the second case, the wind also transports these seeds and organisms, but over long distances, to new zones, etc. p. Atmospheric pressure has a very significant ecological impact, especially on vertebrates, which because of this cannot live above 6000 m above sea level.[...]

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ABIOTIC ENVIRONMENTAL FACTORS are components and phenomena of inanimate, inorganic nature that directly or indirectly affect living organisms. Among them, the dominant role is played by climate (solar radiation, light conditions, temperature, humidity, precipitation, wind, pressure, etc.); then there are edaphic (soil), important for animals living in the soil; and, finally, hydrographic, or factors of the aquatic environment. Solar radiation is the main source of energy that determines the heat balance and thermal regime of the biosphere. Thus, the total solar radiation arriving at the earth's surface in the direction from the equator to the poles decreases by approximately 2.5 times (from 180-220 to 60-80 kcal/cm2 year). Based on the radiation regime and the nature of atmospheric circulation, climate zones are distinguished on the Earth's surface. However, solar radiation, in turn, serves as the most important environmental factor influencing the physiology and morphology of living organisms. The existence on the surface of our planet of large zonal types of vegetation (tundra, taiga, steppes, deserts, savannas, tropical rainforests, etc.) is mainly due to climatic reasons; and they are closely related to climatic zonation.[...]

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Storms are of great importance, although their effect is purely local. Hurricanes, and even ordinary winds, are capable of transporting animals and plants over long distances and, thus, changing the composition of forest communities for many years. A recent work on the forests of New England (Oliver, Stephens, 1977) reports that the structure of the local vegetation is still noticeable the effect of two hurricanes that swept through these places before 1803. It was noted that in those areas where, it would seem, the possibility of settlement insects are the same in all directions; they disperse faster in the directions of the prevailing winds. In dry areas, wind is a particularly important limiting factor for plants because it increases the rate of water loss through transpiration and, as already noted, desert plants have many special adaptations to mitigate this limiting effect.