Animals that live in the soil. Inhabitants of the soil. Ecological groups of soil animals. Ecological groups of organisms in relation to edaphic factors. Fat - different
Inhabitants of the soil. We had to look at the land in the yard, in the garden, in the field, on the river bank. Have you seen how little bugs are swarming in the ground? The soil is literally saturated with life - rodents, insects, worms, centipedes and other living organisms live in it at different depths. If these inhabitants of the soil are destroyed, the soil will not be fertile. If the soil becomes unfertile, then in winter we will have nothing to eat.
Inhabitants of the soil. Everyone is familiar with these animals - both adults and children. They live right under our feet, although we don’t always notice them. Lazy earthworms, clumsy larvae, nimble centipedes are born from earthen lumps crumbling under a shovel. Often we disdainfully throw them aside or immediately destroy them as pests of garden plants. How many of these creatures inhabit the soil and who are they our friends or enemies? Let's try to figure it out...
About the most inconspicuous... Plant roots, mycelium various mushrooms penetrate the soil. They absorb water and dissolved in it mineral salts. There are especially many microorganisms in the soil. So, in 1 sq. cm of soil contains tens and even hundreds of millions of bacteria, protozoa, single-celled fungi and even algae! Microorganisms decompose dead remains of plants and animals into simple minerals, which, dissolving in soil water, become available to plant roots.
Multicellular inhabitants of the soil Larger animals also live in the soil. These are primarily various mites, slugs, and some insects. They do not have special devices for digging passages in the soil, so they live shallow. But earthworms, centipedes, and insect larvae can make their own way. The earthworm pushes the soil particles apart with the head section of the body or “bites”, passing it through itself.
And now - about the largest ones... The largest permanent inhabitants of the soil are moles, shrews and mole rats. They spend their entire lives in the soil, in complete darkness, so they have undeveloped eyes. Everything about them is adapted for life underground: an elongated body, thick and short fur, strong digging front legs in the mole and powerful incisors in the mole rat. With their help they create complex systems passages, traps, storerooms.
Soil is home to a huge number of living organisms! So, numerous organisms live in the soil. What challenges do they face? Firstly, the soil is quite dense, and its inhabitants must live in microscopically small cavities or be able to dig and make their way. Secondly, light does not penetrate here, and the life of many organisms passes in complete darkness. Thirdly, there is not enough oxygen in the soil. But it is fully provided with water; it contains a lot of mineral and organic substances, the supply of which is constantly replenished by dying plants and animals. In the soil there are no such sharp temperature fluctuations as on the surface. All this creates favorable conditions for the life of numerous organisms. The soil is literally saturated with life, although it is not as noticeable as life on land or in a body of water.
We have known these animals since childhood. They live in the soil, under our feet: lazy earthworms, clumsy larvae, nimble centipedes are born from earthen lumps crumbling under a shovel. Often we disdainfully throw them aside or immediately destroy them as pests of garden plants. How many of these creatures inhabit the soil and who are they? friends or enemies?
The study of soil-dwelling animals is the subject of a special branch of science - soil zoology, which was formed only in the last century. After experts have developed methods for recording and recording these animals, which is associated with significant technical difficulties, the eyes of zoologists saw a whole kingdom of creatures, diverse in structure, lifestyle and their significance in the natural processes occurring in the soil. By biological diversity animal world soils can only be compared with coral reefs- a classic example of the richest and most diverse natural communities on our planet.
Gullivers are here too, it seems earthworms, and Lilliputians, who cannot be seen with the naked eye. In addition to small sizes (up to 1 mm), most soil-dwelling invertebrate animals also have invisible coloring body covers, whitish or gray, so they can only be seen after special treatment with fixatives, under a magnifying glass or microscope. Lilliputians form the basis of the animal population of the soil, the biomass of which reaches hundreds of centners per hectare. If we talk about the number of earthworms and other large invertebrates, then it is measured in tens and hundreds per 1 m2, and small forms - in hundreds of thousands and even millions of individuals. Here, for example, are the simplest and roundworms (nematodes), with body sizes up to one hundredth of a millimeter. In terms of their physiology, these are typically aquatic creatures capable of breathing oxygen dissolved in water. The smallest sizes allow such animals to be content with microscopic droplets of moisture filling narrow soil cavities. There they move, find food, and reproduce. When the soil dries out, these creatures are able to remain in an inactive state for a long time, becoming covered on the outside with a dense protective shell of solidified secretions.
The larger Lilliputians include soil mites, springtails, and small worms - the closest relatives of earthworms. These are already real land animals. They breathe atmospheric oxygen, inhabit airborne subsoil cavities, root passages, and burrows of larger invertebrates. Their small size and flexible body allow them to use even the narrowest gaps between soil particles and penetrate into the deep horizons of dense soils. loamy soils. For example, oribatid mites go 1.5-2 m deep. For these small soil inhabitants, the soil is also not a dense mass, but a system of passages and cavities connected to each other. Animals live on their walls, like in caves. Overmoistening of the soil turns out to be just as unfavorable for its inhabitants as drying out.
Soil invertebrates with body sizes larger than 2 mm are clearly visible. Here we encounter various groups of worms, terrestrial mollusks, crustaceans (woodlice, amphipods), spiders, harvestmen, pseudoscorpions, centipedes, ants, termites, larvae (beetles, dipterous and hymenopteran insects), and butterfly caterpillars. To the inhabitants underground kingdom Also belong to some species of vertebrates that live in burrows and feed on soil invertebrates or plant roots. These are the well-known moles, gophers, etc. The soil passages are too small for them, so the giants had to acquire special devices for moving in dense substrate.
Earthworms and some insect larvae have highly developed muscles. By contracting their muscles, they increase the diameter of their body and push soil particles apart. Worms swallow soil, pass it through their intestines and move forward, as if eating through the soil. Behind them they leave their excrement with metabolic products and mucus, abundantly secreted in the intestinal cavity. The worms cover the surface of the burrow with these mucous lumps, strengthening its walls, so such burrows remain in the soil for a long time.
And insect larvae have special formations on the limbs, head, and sometimes on the back, with which they act like a shovel, scraper or pick. For example, the front legs are transformed into highly specialized digging tools - they are expanded, with jagged edges. These scrapers are capable of loosening even very dry soil. In beetle larvae, which dig to a considerable depth, the upper jaws, which have the form of triangular pyramids with a jagged top and powerful ridges on the sides, serve as loosening tools. The larva hits the soil lump with these jaws, breaks it into small particles and scoops them up under itself.
Other large inhabitants soils live in existing cavities. They are usually very flexible thin body and can penetrate very narrow and winding passages.
The burrowing activity of animals has great importance for soil. The passage system improves its aeration, which favors root growth and the development of aerobic microbial processes associated with humification and mineralization of organic material. It is not for nothing that Charles Darwin wrote that long before man invented the plow, earthworms learned to cultivate the soil correctly and well. He dedicated a special book to them, “The Formation of the Soil Layer by Earthworms and Observations on the Lifestyle of the latter.”
IN last years There are many publications about these animals that can quickly process plant residues, manure, household waste, turning them into high quality " vermicompost" In many countries, including ours, they have learned to breed worms on special farms to obtain organic fertilizers and as a source of feed protein for fish and poultry.
The following examples will help to evaluate the contribution of invisible soil organisms in the formation of its structure. Thus, ants building soil nests throw more than a ton of soil per 1 hectare to the surface from deep layers of soil. In 8-10 years they process almost the entire horizon populated by them. And desert woodlice, living in Central Asia, lift soil enriched with elements of mineral nutrition of plants from a depth of 50-80 cm to the surface. Where the colonies of these woodlice are located, the vegetation is taller and denser. Earthworms are capable of processing up to 110 tons of earth per 1 hectare per year. This is on our soddy-podzolic soils near Moscow.
Moving in the ground and feeding on dead plant debris, animals mix organic and mineral soil particles. By dragging ground litter into deep layers, they thereby improve the aeration of these layers and promote the activation of microbial processes, which leads to the enrichment of the soil with humus and nutrients. It is animals who, through their activities, create the humus horizon and soil structure.
Man has learned to fertilize it and get high yields. Does this replace animal activities? To some extent, yes. But with intensive land use modern methods, when the soil is overloaded with chemicals ( mineral fertilizers, pesticides, growth stimulants), with frequent disturbances of its surface layer and its compaction by agricultural machines, deep disturbances of natural processes occur, which lead to gradual soil degradation and a decrease in its fertility. Excessive amounts of mineral fertilizers poison the soil and deteriorate the quality of agricultural products.
Chemical treatments destroy not only pests in the soil, but also beneficial animals. This damage takes years to repair. Today, during the period of greening of our economy and our thinking, it is worth thinking about what criteria to assess the damage caused to the crop. Until now, it was customary to count only losses from pests. But let's also count the losses caused to the soil itself from the death of soil formers.
To preserve the soil, this unique natural resource The earth, capable of self-restoring its fertility, must first of all preserve its animal world. Little visible and invisible workers are doing what a person with his powerful technology cannot yet do. They need to be protected not only in nature reserves and national parks, but also on lands used by humans. Animals need a stable environment. They need oxygen in the system of passages made and a supply of organic residues, shelters that are not disturbed by humans, where animals breed and find shelter from cold and drought. And we carefully remove the remains of roots and stems from the beds, trample the soil around the beds, and apply mineral fertilizers that dramatically change the composition of the soil solution. Reasonable management of agriculture, including homesteading, is also the creation of suitable conditions for preserving the fauna of the soil - the key to its Seven years ago on its garden plot subject to water erosion, I switched to a sod-humus soil maintenance system. The site is located on the Volga slope with a slope of 30-50°...
Soil is the habitat for many organisms. Creatures that live in the soil are called pedobionts. The smallest of them are bacteria, algae, fungi and single-celled organisms that live in soil waters. In one m? can live up to 10?? organisms. Invertebrate animals such as mites, spiders, beetles, springtails and earthworms live in the soil air. They feed on plant remains, mycelium and other organisms. Invertebrate animals live in the soil, one of them is the mole. It is very well adapted to living in completely dark soil, so it is deaf and almost blind.
The heterogeneity of the soil leads to the fact that for organisms different sizes it acts as a different environment.
For small soil animals, which are collectively called nanofauna (protozoa, rotifers, tardigrades, nematodes, etc.), the soil is a system of micro-reservoirs.
To slightly larger air-breathing animals, the soil appears as a system of small caves. Such animals are collectively called microfauna. The sizes of representatives of soil microfauna range from tenths to 2-3 mm. This group includes mainly arthropods: numerous groups of mites, primary wingless insects (collembolas, protura, two-tailed insects), small species winged insects, centipedes symphylos, etc. They do not have special adaptations for digging. They crawl along the walls of soil cavities using their limbs or wriggling like a worm. Soil air saturated with water vapor allows breathing through the covers. Many species do not have a tracheal system. Such animals are very sensitive to drying out.
Larger soil animals, with body sizes from 2 to 20 mm, are called representatives of mesofauna. These are insect larvae, millipedes, enchytraeids, earthworms, etc. For them, the soil is a dense medium that provides significant mechanical resistance when moving. These are relatively large forms move in the soil either by expanding natural wells by pushing apart soil particles, or by digging new passages.
Megafauna or soil macrofauna are large diggers, mainly mammals. A number of species spend their entire lives in the soil (mole rats, mole moles, moles, moles of Eurasia, golden moles of Africa, marsupial moles of Australia, etc.). They create entire systems of passages and burrows in the soil. Appearance And anatomical features These animals reflect their adaptation to a burrowing underground lifestyle.
In addition to the permanent inhabitants of the soil, among large animals one can distinguish a large ecological group of burrow inhabitants (gophers, marmots, jerboas, rabbits, badgers, etc.). They feed on the surface, but reproduce, hibernate, rest, and escape danger in the soil. A number of other animals use their burrows, finding in them a favorable microclimate and shelter from enemies. Burrowers have structural features characteristic of terrestrial animals, but have a number of adaptations associated with the burrowing lifestyle.
All around us: on the ground, in the grass, in the trees, in the air - life is in full swing everywhere. Even a resident who has never gone deep into the forest big city often sees birds, dragonflies, butterflies, flies, spiders and many other animals around him. The inhabitants of reservoirs are also well known to everyone. Everyone, at least occasionally, has seen schools of fish near the shore, water beetles or snails.
But there is a world hidden from us, inaccessible to direct observation - a peculiar world of soil animals.
There is eternal darkness there; you cannot penetrate there without destroying the natural structure of the soil. And only isolated, accidentally noticed signs show that beneath the surface of the soil among the roots of plants there is a rich and diverse world animals. This is sometimes evidenced by mounds above mole holes, holes in gopher holes in the steppe or sand swallow holes in a cliff above the river, piles of earth on the path thrown out by earthworms, and the earthworms themselves crawling out after the rain, as well as masses unexpectedly appearing literally from underground winged ants or fatty larvae of cockchafers that are caught when digging up the ground.
Soil is usually called the surface layer earth's crust on land, formed during the weathering of bedrock under the influence of water, wind, temperature fluctuations and the activities of plants, animals and humans. The most important property of soil, which distinguishes it from infertile parent rock, is fertility, i.e., the ability to produce a crop of plants.
As a habitat for animals, soil is very different from water and air. Try waving your hand in the air - you will notice almost no resistance. Do the same in water - you will feel significant resistance from the environment. And if you put your hand in a hole and cover it with earth, it will be difficult to pull it back out. It is clear that animals can move relatively quickly in the soil only in natural voids, cracks or previously dug passages. If there is nothing of this in the way, then the animal can advance only by breaking through a passage and raking the earth back or swallowing the earth and passing it through the intestines. The speed of movement in this case, of course, will be insignificant.
Every animal needs to breathe to live. The conditions for breathing in soil are different than in water or air. Soil consists of solid particles, water and air. Solid particles in the form of small lumps occupy slightly more than half of its volume; the rest falls on the gaps - pores, which can be filled with air (in dry soil) or water (in soil saturated with moisture). As a rule, water covers all soil particles with a thin film; the rest of the space between them is occupied by air saturated with water vapor.
Thanks to this structure of the soil, numerous animals live in it and breathe through their skin. If you take them out of the ground, they quickly die from drying out. Moreover, hundreds of species of real freshwater animals live in the soil, inhabiting rivers, ponds and swamps. True, these are all microscopic creatures - lower worms and single-celled protozoa. They move and float in a film of water covering soil particles. If the soil dries out, these animals secrete a protective shell and seem to fall asleep.
Soil air receives oxygen from the atmosphere: its amount in the soil is 1-2% less than in atmospheric air. Oxygen is consumed in the soil by animals, microorganisms, and plant roots. They all highlight carbon dioxide. There is 10-15 times more of it in soil air than in the atmosphere. Free gas exchange between soil and atmospheric air occurs only if the pores between the solid particles are not completely filled with water. After heavy rains or in the spring, after the snow melts, the soil is saturated with water. There is not enough air in the soil, and under the threat of death, many animals leave it. This explains the appearance of earthworms on the surface after heavy rains.
Among soil animals there are also predators and those that feed on parts of living plants, mainly roots. There are also consumers of decomposing plant and animal residues in the soil - perhaps bacteria also play a significant role in their nutrition.
Soil animals find their food either in the soil itself or on its surface.
The life activity of many of them is very useful. The activity of earthworms is especially useful. They drag a huge amount of plant debris into their burrows, which contributes to the formation of humus and returns substances extracted from it by plant roots to the soil.
In forest soils, invertebrates, especially earthworms, process more than half of all leaf litter. Over the course of a year, on each hectare, they throw out to the surface up to 25-30 tons of land they have processed, turned into good, structural soil. If you distribute this soil evenly over the entire surface of a hectare, you will get a layer of 0.5-0.8 cm. Therefore, it is not for nothing that earthworms are considered the most important soil builders. Not only earthworms “work” in the soil, but also their closest relatives - smaller whitish annelids(enchytraeids, or pot worms), as well as some types of microscopic roundworms (nematodes), small mites, various insects, especially their larvae, and, finally, woodlice, centipedes and even snails.
Medvedka
The purely mechanical work of many animals living in it also affects the soil. They make passages, mix and loosen the soil, and dig holes. All this increases the number of voids in the soil and facilitates the penetration of air and water into its depth.
This “work” involves not only relatively small invertebrate animals, but also many mammals - moles, shrews, marmots, ground squirrels, jerboas, field and forest mice, hamsters, voles, mole rats. The relatively large passages of some of these animals go deep from 1 to 4 m.
The passages of large earthworms go even deeper: in most of them they reach 1.5-2 m, and in one southern worm even 8 m. These passages, especially in denser soils, are constantly used by plant roots penetrating into the depths. In some places, such as steppe zone, a large number of passages and holes are dug in the soil by dung beetles, mole crickets, crickets, tarantula spiders, ants, and in the tropics - termites.
Many soil animals feed on roots, tubers, and plant bulbs. Those of them who attack cultivated plants or at forest plantations, are considered pests, for example the cockchafer. Its larva lives in the soil for about four years and pupates there. In the first year of life, it feeds mainly on the roots of herbaceous plants. But, as it grows, the larva begins to feed on the roots of trees, especially young pines, and causes great harm to the forest or forest plantations.
Mole paws are well adapted for life in the soil.
The larvae of click beetles, darkling beetles, weevils, pollen eaters, caterpillars of some butterflies, such as cutworms, the larvae of many flies, cicadas and, finally, root aphids, such as phylloxera, also feed on roots various plants, greatly harming them.
A large number of insects that damage the above-ground parts of plants - stems, leaves, flowers, fruits, lay eggs in the soil; Here, the larvae that emerge from the eggs hide during drought, overwinter, and pupate. Soil pests include some species of mites and centipedes, naked slugs and extremely numerous microscopic roundworms - nematodes. Nematodes penetrate from the soil into the roots of plants and disrupt their normal functioning. There are many predators living in the soil. “Peaceful” moles and shrews eat huge amounts of earthworms, snails and insect larvae; they even attack frogs, lizards and mice. These animals eat almost continuously. For example, a shrew eats an amount of living creatures per day equal to its own weight!
There are predators among almost all groups of invertebrates living in the soil. Large ciliates feed not only on bacteria, but also on protozoa, such as flagellates. The ciliates themselves serve as prey for some roundworms. Predatory mites attack other mites and small insects. Thin, long, pale-colored geophilic centipedes that live in soil cracks, as well as larger dark-colored drupes and centipedes that stay under stones and in stumps, are also predators. They feed on insects and their larvae, worms and other small animals. Predators include spiders and related haymakers (“mow-mow-leg”). Many of them live on the soil surface, in the litter, or under objects lying on the ground.
Antlion larva.
Soil organism - any organism that lives in the soil throughout all or a certain stage life cycle. Organisms living in soil range in size from microscopic ones that process decaying organic materials to small mammals.
All organisms in soil play an important role in maintaining soil fertility, structure, drainage and aeration. They also destroy plant and animal tissue, releasing accumulated nutrients and transforming them into forms used by plants.
Eat soil organisms pests such as nematodes, symphylids, beetle larvae, fly larvae, caterpillars, root aphids, slugs and snails, which cause serious damage to crops. Some cause rot, others release substances that inhibit plant growth, and some host organisms that cause animal disease.
Since most organisms' functions are beneficial to the soil, their abundance affects fertility levels. One square meter Rich soil can contain up to 1,000,000,000 different organisms.
Groups of soil organisms
Soil organisms are generally divided into five arbitrary groups based on size, the smallest of which are bacteria and algae. Next comes the microfauna - organisms smaller than 100 microns that feed on other microorganisms. The microfauna includes single-celled protozoa, some species of flatworms, nematodes, rotifers and tardigrades. The mesofauna is somewhat larger and more heterogeneous, including creatures that feed on microorganisms, decaying matter, and living plants. This category includes nematodes, mites, springtails, proturuses and pauropods.
The fourth group, macrofauna, is also very diverse. The most common example is dairy white worm, which feeds on fungi, bacteria and decaying plant material. This group also includes slugs, snails and those that feed on plants, beetles and their larvae, as well as fly larvae.
Megafauna includes large soil organisms such as earthworms are perhaps the most useful creatures that live in top layer soil. Earthworms provide soil aeration processes by breaking down litter on the soil surface and moving organic matter vertically from the surface to the subsoil. This has a positive effect on fertility and also develops the matrix structure of the soil for plants and other organisms. It has been estimated that earthworms completely recycle the equivalent of all the planet's soil to a depth of 2.5 cm every 10 years. Some vertebrates are also included in the group of soil megafauna; these include all kinds of burrowing animals such as snakes, lizards, gophers, badgers, rabbits, hares, mice and moles.
The role of soil organisms
One of the most important roles soil organisms is to recycle the complex substances of decaying flora and fauna so that they can be used again by living plants. They act as catalysts in a number of natural cycles, among which the most prominent are the carbon, nitrogen and sulfur cycles.
The carbon cycle begins with plants, which use carbon dioxide from the atmosphere with water to produce plant tissues such as leaves, stems and fruits. Then they feed on plants. The cycle is completed after the death of animals and plants, when their decomposing remains are eaten by soil organisms, thereby releasing carbon dioxide back into the atmosphere.
Proteins serve as the main material of organic tissues, and nitrogen is the main element of all proteins. The availability of nitrogen in forms that can be used by plants is a major determinant of soil fertility. The role of soil organisms in the nitrogen cycle is of great importance. When a plant or animal dies, it breaks down complex proteins, polypeptides and nucleic acids in their bodies and produce ammonium, ions, nitrates and nitrites, which plants then use to create their tissues.
Both bacteria and blue-green algae can fix nitrogen directly from the atmosphere, but this is less productive for plant development than the symbiotic relationship between rhizobium bacteria and legumes, as well as some trees and shrubs. In exchange for secretions from the host, which stimulate their growth and reproduction, microorganisms fix nitrogen in the root nodules of the host plant.
Soil organisms also participate in the sulfur cycle, primarily by breaking down naturally abundant sulfur compounds in the soil so that this vital element is available to plants. The rotten egg smell so common in wetlands is caused by hydrogen sulfide produced by microorganisms.
Although soil organisms have become less important in agriculture Due to the development of synthetic fertilizers, they play a vital role in the process of humus formation for forests.
Fallen tree leaves are not suitable for food for most animals. After the water-soluble components of the leaves are washed away, fungi and other microflora process the hard structure, making it soft and pliable for a variety of invertebrate animals that break the litter into mulch. Wood lice, fly larvae, springtails and earthworms leave relatively unaltered organic droppings, but they provide a suitable substrate for primary decomposers who process it into simpler chemical compounds.
Therefore, the organic matter in the leaves is constantly digested and processed by groups of ever smaller organisms. Ultimately, the remaining humic substance may be as little as one-quarter of the original organic matter bedding. Gradually, this humus is mixed with the soil with the help of burrowing animals (for example, moles) and under the influence of earthworms.
Although some soil organisms can become pests, especially when the same crop is continually grown in the same field, encouraging the spread of organisms that feed on its roots. However, they are an important element in the processes of life, death and decay that rejuvenate environment planets.