III. Floating scaffolding food chains The ocean is made up of phytoplankton, microscopic unicellular organisms that are at the same time true plants. Phytoplankton is called the grass of the sea, but this plant community can also be viewed as

V. Brown Algae Forests In the sea, algae often form almost true forests. A scuba diver diving near La Jolla - Monterey, San Juan Island, Amchitka and many other points, would understand why one can speak of a forest. In these places, even in height

Arborist - owner of the forest

In summer, lush crowns of deciduous trees create a dense shade. Therefore, light-loving forest plants bloom in the spring, when the leaves on the trees have not yet blossomed. Other forest plants have adapted to the lack of light. In the glades, where there is a lot of sun, grasses and flowers grow rapidly all summer. Large herbivorous deer graze here. They eat young shoots of trees and shrubs, preventing clearings from overgrowing.

In the broad-leaved forests of Eurasia live fallow deer, roe deer, spotted deer and noble olein, which are also called deer or red deer. red deer live in small groups. males most years are kept separate from females. Only males have horns. In early spring, they shed their old horns and new ones begin to grow in them, which are finally formed by the beginning of autumn. In early autumn, deer begin mating season- the rut, accompanied by a roar and fights of males. Deer grapple with branched antlers, trying to knock down an opponent. The winner gathers several females around him, protecting them from other males. And in spring, females give birth to one calf. The mother spends a whole year with the baby, protecting him from danger. The spotted skin of deer camouflages them well among the light and shadow of the forest.

Forests are temperate latitudes - the ecosystem most severely affected by human activity. These forests, which once occupied vast areas of Europe and Asia, were cut down for agricultural land, the construction of villages and cities, and as a result, many species of animals and plants disappeared. Now in Europe, only small areas of untouched forests have survived, most of which have become nature reserves. Reserves are protected areas of wildlife, but which are located rare species animals and plants. Any economic activity is prohibited in the reserves.

Belovezhskaya Pushcha - reserve; located on the border of Belarus and Poland, is one of the last untouched forests in Europe. Here and vivo dwells rare wild bull- bison. Long time the bison was an object of hunting and at the beginning of our century completely disappeared in the wild, surviving only in zoos. In many countries, measures were taken to restore the number of bison - they were bred in nurseries and released into the wild. Now in many reserves there are herds of wild bison, and this animal is no longer threatened with extinction.

Boars live in the forests of Europe and Asia - omnivorous wild pigs. They prefer damp swampy places where they like to wallow in the mud. An adult male - a billhook - has sharp long fangs resembling daggers. Cleavers dig with fangs

juicy roots from the ground, defend themselves from enemies and fight for the female. A female boar is sometimes called a pig. It is she who builds a large nest from boughs and spruce branches for her offspring - Gaina. Its bottom is covered with moss, grass and leaves, so that the piglets are warm and cozy.

Beavers are skilled dam builders. These large rodents block forest rivers: sharp teeth they gnaw the trunks of young trees, fell them and drag them to the river, where they lay them in heaps on the bottom, fixing them with clay and stones. In the resulting dam, a beaver hut is being built - a nest for a female with cubs. When the water level rises, the beavers build new floors so that the top of the nest is above the water. And the entrance to the nest, for security reasons, is arranged under water. In summer, beavers feed on tree bark, leaves, and grass. For the winter, they store wood, the warehouse of which is arranged at the bottom of the river. As a result of the activity of beavers, the water of blocked rivers sometimes floods large areas of the forest.

Badgers - representatives of the mustelid family - are excellent underground builders. They live in families, digging complex burrows underground with a cozy nesting chamber, several entrances and many otnorok - dead ends and pantries. There are even special spaces in these holes - the Badger's toilets are very clean, they constantly clean and expand their housing. Badger settlements gradually grow, turning into underground settlements that can last up to a hundred years.

Badger otnorki often populate other forest dwellers such as foxes. Foxes are sluts, and if they settle nearby, clean badgers sometimes leave their holes themselves.

The forest is full of life - damp lowlands and streams are inhabited by frogs and newts, under tree bark, many insects live in the forest floor, butterflies fly over the flowers, and nimble lizards hide in the crevices of stones

In spring and summer, songbirds, titmouse, robin, warbler, song thrush and nightingale fill the forest with their trills. Some of them feed on fruits and seeds, others catch insects.

Jay - large forest bird- in the summer it steals eggs and chicks of other birds, and in autumn, like a squirrel, it stocks up acorns for the winter, burying them in the ground. The Sparrowhawk is the main gate of the forest birdies. This wasp has rounded wings that allow it to easily maneuver through the trees while chasing prey.

Deciduous forests are located along the southern edge of the forest zone.

Among deciduous species, broad-leaved species are distinguished, which have large leaves(oak, maple, ash, beech, elm, elm, etc.), and small-leaved (birch, aspen). The former are relatively shade-tolerant, so their plantations are shady. The latter need a significant amount of light, and the forests of them are light. Obviously, in connection with such an attitude towards light, broad-leaved species in the struggle against small-leaved species gain the upper hand and form the most stable phytocenoses.

From deciduous forests The most widespread in the USSR are oak forests, or oak forests. They are floristically richer than coniferous forests, almost always contain impurities of ash, linden, maple, elm, elm, and in the west - beech and hornbeam; in the second tier there are wild apple trees and maples, the undergrowth usually consists of hazel or forest hazel. Since oak forests belong to ancient phytocenoses that developed back in the Tertiary, develop in a mild climate and on rich soils, they have a complex structure: they usually have two tree tiers, two shrubs, and the grass cover also breaks up into three or four tiers. The grass cover includes grasses with wide leaf blades, the same sedges, various dicotyledons, etc. When they die, all these plants form a thick dead layer that interferes with the development of a moss carpet, which, as a rule, is absent in oak forests.

In the spring, while the oak leaves have not yet unfolded, numerous oak ephemera develop, forming a colorful carpet of yellow anemone, lilac corydalis, azure snowdrops, pink toothbrush, etc. Snowdrops appear right from under the snow.

In the first half of summer, linden blossoms, and the herbaceous vegetation becomes poorer; this impoverishment progressively increases until autumn, when the grass dries up, although some spring species bloom a second time. Plants that bloom in the spring before the forest is shaded have mostly yellow or pink-purple corollas, while those that bloom already in the shade of oak crowns have white corollas.

Oak forests of Eurasia are typical for continental climate. In more favorable conditions, they are replaced by beech forests, and in a mild Mediterranean-Atlantic climate by chestnut forests. In Western Europe and the Caucasus leading role beech forests play, in Middle-earth they are joined by walnut forests.

Deciduous forests in North America are very diverse. In the area of ​​the Appalachian Mountains (34-40°N), the lowest vertical zone is represented by a belt of chestnut forests, which are distinguished by a wide variety of species. The oak distribution area, gravitating towards the Great Lakes region, is characterized by plantations of red oak (Quercus rubra), black oak (Q. velutina), white oak (Q. alba), hickory (Hicoria ovata), etc. forests of Nyssa aquatica and swamp cypress Taxodium distichum grow in water areas; in places less flooded, in addition to these species, ash and poplar also grow, and in even drier places - Caribbean pine, oak, ash, hickory, red maple, etc.

Between areas occupied deciduous forests, and the taiga zone is often located mixed forests, where coniferous and deciduous species are found.

They occupy a much smaller area in the forest zone than the taiga. They grow in the west of the European part of Russia and in the south of the Far East.

In Siberia, mixed and broad-leaved forests are absent: there the taiga passes directly into the steppe.

More than 90% of mixed forests consist of coniferous and small-leaved species. This is mainly spruce and pine with an admixture of birch and aspen. broad-leaved species in mixed forests few. Broad-leaved forests consist mainly of oak, linden, maple, elm, in the southwestern regions - ash, hornbeam, beech. Same breeds but native species presented also on Far East, where, in addition, grow Manchurian walnut, grapes and creepers.

The northern boundary of the distribution of the zone lies approximately along 57 ° N. sh., above which the oak disappears, and the southern one adjoins the northern border of the forest-steppe, where the spruce disappears. This territory forms, as it were, a triangle with peaks in Leningrad, Sverdlovsk, and Kyiv.

Mixed and broad-leaved forests are located mainly on the East European Plain, which has a flat, low-lying surface interrupted by a number of uplands. Here are the sources, watersheds and pools largest rivers European part of Russia: Volga, Dnieper, Western Dvina. On floodplains, forests are interspersed with lush meadows, and on watersheds - plowed fields. Due to the proximity of groundwater and limited runoff, flat lowlands are heavily swamped in places (Polesie, Meshchera). In addition to forest swamps and lakes, in some areas there are sandy soils covered with pine. In forests on clearings and swamps, many berry bushes and herbs grow.

Compared to the taiga, the climate of mixed and deciduous forests is less severe. Winter is not so long and frosty, summer is warm. average temperature January -10...-11°С, and July + 18...+19°С. The average annual rainfall is from 800 to 400 mm. In general, the climate is transitional from maritime to continental in the direction from west to east. If in the Baltic States and Belarus the proximity of the sea smooths out the difference between the air temperature in summer and winter, then in the Vyatka and Kama basins it becomes significant. In summer, the air here warms up to +40°С, and in winter frosts reach -45°С. In all seasons of the year, winds that carry moisture from the Atlantic Ocean prevail.

The snow cover is less thick than in the taiga, with a layer of 20-30 (in the west) to 80-90 cm (in the east). It lasts an average of 140-150 days a year, in the southern regions - 30-60 days.

With the onset of winter, life in the forests, especially in broad-leaved ones, freezes. Most insectivorous birds fly away to warmer climes, and some of the animals flow into hibernation or sleep ( the bats, hedgehogs, dormouse, badgers, bears). In spring and summer, all tiers of forests are inhabited by various animals.

habitats, environmental disturbances (eg fire), succession and climate change. The scope of research depends on what questions the researchers ask themselves.

and what organisms they study. Most studies are large-scale, conducted using new technologies such as computer geographic Information system that allow you to study large areas with a sufficient degree accuracy. The information obtained can then be used in mathematical models designed to predict changes in landscapes and processes associated with human activity.

Most important processes and phenomena can only be fully understood at the level of landscape ecology. Although landscape ecology still lacks theoretical foundations, it will play an increasingly important role in ecological research in the future.

See also the articles "Scale in Ecology", "Habitats: Fragmentation", "Metapopulation", "Dispersal".

TEMPERATE FORESTS

The best-known type of temperate forests (at least in the northern hemisphere) consists mainly of deciduous trees that shed their leaves in autumn.

Deciduous forests are located in areas that are characterized by fairly large seasonal temperature fluctuations - cool to cold winters and warm summers - as well as high rainfall all year round. Outwardly, this biome, perhaps, shows the greatest variability throughout the year. In winter, most plants are in a dormant state: terrestrial, early flowering plants in winter are presented in the form of bulbs or other underground parts. This allows them to grow quickly in the spring, before the tree canopy cuts off the light.

The forest is a three-dimensional habitat that has several tiers (levels); the total surface area of ​​the leaves is several times the area on which these forests grow. In summer, a thick tree canopy prevents light from reaching the lower level. Some-

rye shade-tolerant plants of the ground layer still grow, especially in lighter parts of the forest. In autumn, trees absorb as much nutrients and minerals as possible from their leaves, which leads to a change in their color before falling off. Fallen leaves are a rich nutrient resource for the soil decomposer community*.

Forests are a dynamic system that develops in time and space. For example, the main tree species in the temperate forests of the American Northeast are temporary associations rather than highly integrated communities. Since the last ice age, each tree species has spread northward independently of the others, and, historically speaking, it was only very recently that their paths crossed to form the forests we see today. The dynamic nature of deciduous forests is also observed at the regional level; forests are not so much a "green blanket" as a "checkered blanket". Human impact on forest areas leads to the fact that in different areas the forest is at different stages of restoration.

See also the article " coniferous forests(taiga)".

* Decomposers - organisms that decompose the dead organic matter(corpses, waste) and converting it into inorganic substances that are able to assimilate other organisms - producers.

LIMITING FACTORS

The concept of limiting factors has been used in agriculture for some time.

economy. Nutrient deficiencies such as nitrates and phosphates can negatively impact crop yields, so nutrient supplements increase yields. In arid regions, in exactly the same way, productivity is increased by water. Here, the limiting factor is understood as a resource that is not enough for the growth needs of plants.

As for populations, a factor is called limiting if its change leads to a change in the average population density. For example, the availability of nesting sites may be considered a limiting factor for a bird population if the installation of nest boxes increases population numbers. In one experiment it was found that shooting pigeons* had no effect on

* A bird of the pigeon family.

population size. The limiting factor in this case was the availability of food; the shooting of birds led to the fact that the survivors had more food left, the population was also replenished by wood doves migrating from other places. In exactly the same way, populations of game birds, such as grouse, are maintained.

Over a period of time (or consecutively over the course of a year) there may be several limiting factors, and they seem to interact with each other to determine the size of the population.

It is important to distinguish between factors that regulate the size of populations and factors that determine their average density. Population size can be controlled only by factors that depend on density (i.e., those that maintain it within certain limits), while the average density of a population is determined by factors both dependent on density and not dependent on it.

The concept of limiting factors plays an important role in many areas of ecology, from the study of interspecific competition to pest control and the prediction of the impact of rising carbon dioxide levels on plant productivity.

See also the articles “Population regulation”, “Top down - bottom up”, “Density dependent factors”.

LUGA

Most of the meadows broad sense, that is, plains with a temperate climate (steppes, prairies, pampas), is located in the interior of the continents, where it is too dry for forests and too wet for deserts. In those areas where the forest could grow, meadows are formed artificially for grazing, for this the forest is burned. Until recently, large mammals grazed almost all natural meadows (only on the plains North America grazed up to 60 million bison).

Winters in such an area are cold to moderate, and summers are hot, resulting in a fire hazard. To the meadows temperate climate accounts for a significant part of the fertile soils, and huge areas of them have been turned by man into agricultural land.

For a better understanding of the ecology of meadows, they are divided into natural, semi-natural and artificial. Natural grasslands arose as a result of climatic changes, processes

owls occurring in the soil, wildlife activity and fires. Semi-natural grasslands (pastures) are formed and modified by human activities, but they are not deliberately planted. Plains can be an example of such meadows. Western Europe cleared from forests. If they are left alone, then after some time forests will grow there.

Where did the plants that now grow in semi-natural meadows come from? There are small meadow areas in the highlands or on infertile soils; individual plants grow on forest edges and glades. Some meadows

Mitchell Paul. 101 key ideas: Ecology - Per. from English. O. Perfilieva. - M.: FAIR-PRESS, 2001. - 224 p. - (101 key ideas).

known for the diversity of their flora, and now they are even protected, preventing them from turning back into a forest.

A significant part of the biomass of plants, fungi and invertebrates in temperate grasslands is underground. Here, symbiont fungi, intertwined with a huge dense mass of roots, form a mycorrhizal* network. It serves as a rich food source for innumerable invertebrates.

See also articles "Biomes", "Savannas", "Symbiosis".

* Mycorrhiza - mutually beneficial cohabitation(symbiosis) of the mycelium of the fungus with the root of a higher plant, such as boletus with aspen.

MACROECOLOGY

In the last decade, an approach called “macroecology” has become increasingly popular in ecology. While most ecologists study in detail the peculiarities of species relationships in small areas over a short period of time, macroecologists think and act on a large scale.

The action of some ecological processes is noticeable only in comparison with others or on a wide time scale, so they cannot be studied experimentally. Here other approaches are needed. One of the possible ones is to observe large-scale processes and phenomena of nature and then look for explanations for them, this is the main essence of macroecology.

Showing that such processes actually occur is not an easy task. In order to isolate any patterns from the confusion of facts, more evidence is needed and more samples to study, so the object of study becomes more

studied species. If there are some regularities, then it is possible to assume that the main ecological processes are universal. General patterns include the gradient of latitudinal diversity, the dependence of the number of species on the size of the territory, as well as the relationship between body size, population size, and area of ​​distribution.

The main problem is the explanation of the processes underlying the regularities. Without an experimental approach, it is not easy to identify differences in processes. In addition, many patterns seem to have not one but several causes, several mechanisms of action, so it can be difficult to determine the importance of a particular process.

The lack of experimental validation has been a major target of criticism of the macro-environmental approach. However, a broad-based approach to ecology is still needed. Many of the criticisms leveled against macroecology were once leveled against fossils as evidence for evolution. But would it be possible to understand the mechanism of evolution without studying fossils?

See also the articles "Gradient of latitudinal diversity", "Dependence of the number of species on the size of the territory", "Scale in ecology", "Generalizations in ecology", "Experimental ecology".

SCALE IN ECOLOGY

Many different ecological processes operate on a much larger (or smaller) spatial and temporal scale than we are familiar with. Space in ecology is measured by values ​​from microscopic to global, and time - from seconds to millennia.

Most environmental studies last no more than five years and cover an area of ​​no more than 10 m2. This is quite significant, since there is no reason to assume that the processes occurring within the framework of any ecological

Mitchell Paul. 101 key ideas: Ecology - Per. from English. O. Perfilieva. - M.: FAIR-PRESS, 2001. - 224 p. - (101 key ideas).

research will remain important on a larger spatial and temporal scale.

According to one definition, ecology is analogous to the reconstruction of a film "from several fragments of the same film or successive fragments of different films, which, we hope, belong to similar films" (Vince et al., 1986). The meaning of this statement is that it is impossible to fully

Tew to understand ecological processes without judging scale. This is well understood, for example, environmentalists fresh water, since it is impossible to know the ecology of rivers without taking into account the processes operating throughout the entire space of their basin. Hence the increasing number of long-term studies that provide a more adequate picture of various ecological processes.

The sizes of organisms that ecologists study range from microscopic (bacteria) to gigantic ( blue whales and sequoias); size is important environmental significance. For example, reproduction rate, population size, and metabolic rate are related to size. In order to move in the water, the movement of the tail is enough for fish, and microorganisms move in the water, as if in thick molasses. In the same way, the significance of various processes changes if they are considered on a different time scale. What seems to us to be an accidental ecological “disturbance” may be a regular process for trees that live hundreds of years.

Do not underestimate the importance that the chosen scale has on the interpretation of processes, so you need to be able to choose it correctly. This is one of the basic rules for an ecologist.

See also the articles "Landscape ecology", "Macroecology".

INTERSPECIES COMPETITION

The prevalence and role of interspecific competition has always been one of the most hotly debated issues in ecology.

Interspecific competition is defined as a relationship between two or more species that is unfavorable to all participants (see "Interspecific Relationships"). Often such a relationship is asymmetric, then one species suffers from competition more than another. There are several ways of negative relationships, ranging from indirect ones, such as competition for limited resources (exploitative competition) or the presence of a predator common to several species (indirect competition), to direct relationships, such as the use of physical or chemical means to drive out a competitor. or depriving him of the opportunity to use resources (active competition). An example of the latter is the actions of the geese. On the rocky shores

free space is highly valued, and the geese take every opportunity to push their neighbors off the rocks.

Darwin argued that interspecific competition should be stronger between closely related species, since they tend to consume similar resources. Although in recent times competition between distant species has also been discovered, Darwin's concept is still valid.

Perceptions about the role of competition have changed over the years. At first it was assumed that it was very common and important, then some ecologists highlighted the role of predation or external influences on the structure of communities. Ecologists later recognized that competition plays an important role among some groups of organisms (for example, plants), but among other groups (for example, herbivorous insects) it is not so much. herbivorous

Mitchell Paul. 101 key ideas: Ecology - Per. from English. O. Perfilieva. - M.: FAIR-PRESS, 2001. - 224 p. - (101 key ideas).