The largest species composition in. Species composition of plants. Chapter II. Mammoth fauna, its origin, habitat conditions and species composition

Each biocenosis is a system that includes many ecologically and biologically various types, which arose as a result of selection and are capable of existing together in specific natural conditions. This system has its own species composition and structure; it is characterized by daily, seasonal and long-term dynamics, and the relationships of organisms both with each other and with the biotope.

Species composition a biocenosis is a systematized collection of species of plants, animals, fungi and microorganisms characteristic of a given biocenosis. The species composition of a phytocenosis is more or less constant compared to a zoocenosis, since animals move. Accounting for fungi and microorganisms is difficult due to excessive species abundance or their microscopic size. The greatest species diversity is found in the biocenoses of tropical rainforests, and the lowest in polar ice deserts.

The number of species of a biocenosis per unit area is called its species saturation. Different systematic groups of organisms in the same biocenosis differ sharply in species richness. Among terrestrial biocenoses, flowering plants are rich in this regard, the species richness of mushrooms and insects is somewhat less, and even less are birds, mammals and other representatives of fauna. In the tundra the greatest species diversity in mosses and lichens. The larger the territory the biocenosis occupies and the more favorable the environmental conditions, the more types oh composition. With a large species composition, we are talking about floristic and faunal richness.

The species that predominate in the biocenosis are called dominants. There are permanent and temporary dominants. The latter dominate only during a short growing season, being replaced by other, also temporary dominants. These include spring ephemeral plants: noble liverwort, oak wood anemone in European temperate forests and tulips in the southern steppes.

In a multi-tiered forest phytocenosis, dominants are present in all tiers. For example, in a pine-juniper-blueberry forest these are pine (tree layer), juniper (shrub layer) and blueberry (living ground cover). Moreover, the dominants upper tier have greater ecological significance than the lower ones. A tier may contain another species that is important, but less important than the dominant - the subdominant. Thus, in a birch-blueberry pine forest, the subdominant is birch if it, together with pine, forms a tree layer. Secondary species (assectators) are included in different tiers. In a biocenosis one can also find anthropophyte plants that have penetrated into the phytocenosis as a result of their deliberate or accidental introduction by humans.

It should be noted that dominance is not always associated with abundance and is a relative concept, especially in the animal world. A dominant is a species that predominates over others, although in a biocenosis it may have low numbers, for example in a desert with extremely sparse grass cover.

The dominants that determine the nature and structure of the biocenosis are called edificators (builders). Basically, these are those plants that create the internal biotic environment of the community: in a pine forest - pine, oak grove - oak, feather grass steppe - feather grass, etc. Subedificators are, as a rule, subdominants.

Approximately five hundred species of birds and three million large animals live on the park's plains. The Serengeti boasts large herds of antelope, elands, klipspringers, dik antelopes, zebras, gazelles, lions, impalas, leopards, cheetahs, hyenas and other large mammals such as rhinoceroses, giraffes, buffalo, topi antelopes, congons, elephants and hippopotamuses. Others include crocodiles, baboons, bat-eared foxes, and chameleons. Prides of lions are content with the abundance of grazing animals on the plains. The favorite place of solitary leopards is the acacia trees growing along the banks of the Seronera River, while cheetahs can be found on the southeastern plains. Here you can also find spotted hyenas, all three species of African jackals and many elusive small predators, from insectivores to beautiful servals. In addition, ostriches, well adapted to life in the dry season, live here, as well as more than 350 species of reptiles, not to mention insects.

The most protected species: African buffalo; Ethiopian jackal; Asian jackal; hyena; African elephant; a lion; serval; black rhinoceros; white rhinoceros; leopard; klipspringer; giraffe; zebra; dik - dik; Thomson's gazelle; black-backed jackal; cheetah; Topi antelope; impala antelope; blue wildebeest.

Kenya. Climate and tourist seasons

The climate is subequatorial. There are two rainy seasons in the year: from October to December and from late March to early June. The rains usually start in the afternoon, and the rest of the time the sun shines brightly. Kenya's climate is the most favorable on the entire African continent. Daytime temperatures rarely drop below 24 degrees. Best time to visit Kenya from June to October. It is very hot between January and March. There is a long rainy season from March to May. During this period, there is a danger of contracting malaria and gastrointestinal infections.

National Park”Tsawo” (Tsawo National Park)

It occupies an area of ​​2,082,114 hectares. Formed in 1948. Semi-desert plateau and hills composed of volcanic rocks. Thorn bush thickets, park savannas with baobab, tree spurges, acacias, grasslands. Elephant, buffalo, black rhinoceros, lion, leopard, hippopotamus, antelopes (lesser kudu, beisa, oryx), 450 species of birds. Located in the southeastern part of the country and divided in half into western and eastern parts by road and by railway Nairobi-Mombasa.

1. Landscapes and its components.

The landscapes of the parks combine rocky mountains, hills, plains and crystal clear lakes. The predominant landscapes are treeless savanna and open forests, with the eastern part being drier. In the moist parts grow ancient baobabs, umbrella trees and acacias with white and pink flowers, desert rose and others exotic plants. Adjacent to Tsavo Parks is the Taita Hills Private Game Reserve.

East Tsavo

This is the less visited part of the park. Part of the territory of this part of the park is occupied by vast forests, home to herds of elephants. The most diverse fauna is located in the Kanderi swamp. But the most famous landmark in this part of the park is the Aruba Dam, built on the Voi River. Most of it is occupied by the Yatta Highlands - a three-hundred-kilometer-long frozen lava flow - a huge desert plain covered with thorns and low-growing acacias. Only the Galana River valley gives freshness to this arid steppe. Along its banks there are green oases and clusters of trees casting shade.

East Tsavo is divided into 2 parts:

the northern bank of the Galana River is closed to the public;
southern zone– from the Voi region in the west to Sal in the east.

West Tsavo

This part of the park is better known and developed, with an extensive road network and infrastructure. The soil in this part is very fertile thanks to the abundant water supply and the volcano, so the vegetation here is very lush. The main attractions are the ponds at Kilaguni and Nguila Lodges, which attract animals during the dry season. In autumn, thousands of birds migrating south from Europe stop to rest near Nguila Lodge. Not far from Kilaguni Lodge is Mzima Springs. On the territory of Z. Tsavo there is the Ngulia mountain range, the plain and the Idawe volcanic upland, created by the Great African Rift, Mount Kilimanjaro and Kenya. Divided into 3 parts:

the northern bank of the Tsavo River is the most visited and suitable place for receiving tourists; Part of the reserve between the river and the road to Taveta;
The southwestern part, where tourists visit only Jipe Lake and Taita Hills. The territory of Western Tsavo extends to the slopes of Kilimanjaro. The most interesting to visit is the northern part of Western Tsavo. There are lakes here that are fed by an underground source. Palm trees, tamarind trees and reeds grow around the clear lakes.

2. Most interesting objects

Springs of Mzima(Tsavo West)

Sources with crystal clean water, which replenish the waters of small ponds where animals come to drink. You can always see crocodiles, hippos and fish living in the reservoir. There is also a specially equipped place for underwater observation of hippos and crocodiles - an underwater camera from which you can look at the animals through glass. Several sources “spit out” about 500 million liters daily pure water, flowing from the glaciers of Kilimanjaro and lost in the rocky deposits of the volcano.

Growling Rocks(Tsavo West)

They owe their name to the cicadas that live in these places, whose constant buzzing hits the bare rocks with the wind and produces an extraordinary roaring effect. From here you have a panoramic view of the expanses of Tsavo Park.

Volcanic block and Shetani cave and Chaimu crater(Tsavo West)

A giant (8 km by 1.6 km) black volcanic block that formed in these places more than 240 years ago. You can climb it and see a small cave in the center. Recent evidence of volcanic activity appears in the crater of the Chaumu volcano. It is also possible to climb it as there is a specific trekking route on it. However, it will not be easy: the ground under your feet will be slippery and at the same time even warm.

Ngulia Nature Reserve(Tsavo West)

Right at the foot of Ngulia Hill there is a protected area of ​​70 square meters. km. There are more than 50 endangered black rhinoceroses protected behind a special fence. Observations of this rare animal species are being organized.

Kanderi Swamps(Tsavo East)

With the exception of the Aruba Platinum, the marshy areas of Kanderi are a natural spring fresh water, and attract a huge number of inhabitants of the African savannah to these places who come to drink.

Lugard Falls

Lugard Falls are rapids on a raging river that disappears from view in a narrow gorge. Also of interest are multi-colored stones that have been subjected to the destructive effects of water and have unusual carved shapes.

3. Species composition of flora and fauna

Animal world very diverse: agama lizards, dwarf mongooses, marabou storks, baboons, antelopes, caracals, gazelles, buffalos, zebras, Masai giraffes, jackals, hyenas, crocodiles, hippos, leopards, lions and cheetahs. More than 60 species of mammals and 400 species of birds live here.

Tsavo elephants are called "red" because of their pink shade skin, which gives them a reddish mud color. There are very few rhinoceroses in Tsavo. The steppe is home to herds of small impala and springbok antelopes. Another inhabitant of the dry, barren steppes is the oryx antelope. Tsavo lions differ from their counterparts in Ngorongoro or Serengeti in their larger size and rare beautiful mane.

South African Republic. Climate and tourist seasons

Tropical in the north and subtropical in the south of the country. The average temperature in January is from +18C to +27C, in July - from +7C to +10C. The best time to visit Kruger National Park is winter (May to September), when it is dry and cool. Daytime temperatures do not exceed +25 degrees. In summer (December, January, February), temperatures can rise above 40 degrees. At this time it often rains with thunderstorms.

Kruger National Park

It occupies an area of ​​1,948,528 hectares. Province of Transvaal. Formed in 1898; until 1926 - Sabie Game Reserve, in 1927 renamed Kruger Park. About a million tourists visit it every year. It extends in a strip of 60 km along the border with Mozambique and is surrounded by a wall 1800 km long. It is one of the 14 largest parks in the world and is the most economically successful wildlife conservation project in the world. The inhabitants of the park and their health are monitored by professional staff: doctors, hunters, rangers. Work is underway to restore the number of animals that are in danger of extinction.

1. Landscapes and its components

Gently hilly terrain, grassy plains, park savannas, dry deciduous forest, thickets of thorny bushes. In the southwest of the park, shrubs and acacias predominate. Large granite rocks are scattered across the ground, covered with abundant vegetation. The central region consists of vast grassy plains that are interrupted by lush river vegetation on the banks of the Olifants and Letaba rivers. In the east, the Olifants River separates the savannah and the arid bush. Mopane trees dominate north of the Olifants River. The southeastern part of the park is open savannah. Closer to the Limpopo River (the northern border of the park), the tropical forest begins, with a large and wide baobab towering above all other trees. The land north of the Levuvhu River offers extraordinary birdwatching opportunities. Numerous ethnographic villages and private reserves.

2. Species composition of flora and fauna

The park is home to more than 250 thousand animals, almost 150 species, including representatives of the big five - 3,200 rhinoceroses, 8,000 elephants, 1,000 leopards, 2,000 lions, 120,000 thousand buffalo and about the same number of impala antelopes. In addition, over 500 species of birds, about 50 species of fish, 150 species of amphibians and reptiles live here, more than 450 species of trees and shrubs, as well as 235 species of grasses. The local elephants are famous for their large tusks. In 1970, the park had its own “seven”: elephants with two tusks weighing more than 45 kg.

The world of birds is very diverse. Here you can see: heron, stork, vulture, hawk, eagle, guinea fowl, plover, wading bird, bustard, pigeon, parrot, owl, kingfisher, bee-eater, roller, hornbill, swallow, nightingale, starling, sunbird, weaver. The park is of great interest to those interested in reptiles, fish, frogs, scorpions, spiders and other arthropods.

Species composition plant communities, or lists of plant species growing in them, is the most important characteristic phytocenoses. In the figurative expression of St. Petersburg University professor, recognized Russian geobotanist V. S. Ipatov: “For a geobotanist, a list of species is nothing more than an alphabet from which a researcher puts together words and sentences when describing communities.” Although highest value in the community have species that are predominant in abundance, when describing the species composition it is necessary to take into account, if possible, all plant species. The fact is that among the species that quantitatively play an insignificant role in the phytocenosis, there may be those whose presence indicates certain features of environmental conditions and the history of community formation. For example, the presence of Potentilla erecta in a meadow even in small quantities ( Potentilla erecta) indicates low soil fertility. These types of plants were called by L. G. Ramensky determinant those. defining. Nowadays the more common concept indicator species, or types of plants, by the presence of which conditions (factors) can be assessed qualitatively or quantitatively external environment. Objects of indication can be various environmental factors: soil characteristics, types of underlying rocks, burial level groundwater etc. For example, indicator species according to the factor of increased content of nitrogen compounds in the soil are stinging nettle ( Urtica dioica), great celandine ( Chelidonium majus) and common raspberry ( Rubus idaeus). The presence of dandelion officinalis ( Taraxacum officinale) indicates a clayey or loamy mechanical composition of the soil, and the presence of creeping buttercup (Ranunculus repens), acute sedge ( Carex acuta) or field mint ( Mentha arvensis) indicates waterlogging of the soil. The predominant species in a community usually find optimal conditions for themselves in it and therefore are less sensitive to certain changes in environmental conditions, although, of course, they also have a certain determining significance.

Analysis of the species composition makes it possible, to one degree or another, to reveal the reason for the formation of a phytocenosis and even look into its past. Yes, in the spruce forests Leningrad region common wood anemone (Anemonoides nemorosa), which indicates soil richness and may indicate that other non-moral species could have grown here previously, including trees - oak (r. Quercus), ash (r. Fraxinus), maple (r. Acer), linden (b. Tilid). Vetrenichka, proving to be more resistant to new conditions, in particular to a change in forest-forming species, was able to maintain its position. Some researchers, in particular P.D. Yaroshenko (1969), consider the anemone as a historical determinant, reflecting environmental conditions in the past, in this case - a relic of the Atlantic

(non-moral) period, which was 6000 years ago and is considered the “climatic optimum”.

An essential feature of a phytocenosis is the number of species. The total number of species for the entire phytocenosis determines species richness. Another indicator is obtained by calculating the average number of species per unit area, for example per square measuring 10x10 m (100 m2) or 1x1 m (1 m2). The number of species per unit area is called species richness. IN different types phytocenoses, large differences are found in the values ​​of this indicator (Table 3).

Table 3. Species richness of phytocenoses middle zone Russia

The number of species in a phytocenosis is determined by many factors, for example:

• 1) species pool (potential influx of diaspores), which is determined by the total stock of flora of the area and the possibility of the arrival of its rudiments;
• 2) ecotope (environmental conditions); is a real “sieve” - the more favorable the conditions, the larger the sieve cells and the greater the number of species that can grow in a given area;
• 3) cenotope (phytocenotic selection); determined by the system of relationships between plant species and can lead to the elimination, limitation or favoring of some by others;
• 4) heterogeneity of the environment - the higher the heterogeneity of the environment, the more opportunities for the growth of different species and the greater the species diversity;
• 5) history of the formation of the phytocenosis and its age;
• 6) economic activity person; can either increase species richness as a result of increased environmental heterogeneity or the appearance of adventive (adventive) species, or reduce it due to excessive exploitation natural resources. Cultivation of monocultures over large areas, excessive grazing, repeated mowing, unregulated collection of medicinal raw materials - all this can lead to depletion of the flora.

It should be noted that most often the most floristically rich phytocenoses arise in cases where no single plant species in the community is an absolute dominant, i.e., does not use resources to a greater extent than other species, and where the above factors overlap another.

IN Russian Federation The greatest species richness is typical for the phytocenoses of the southern part of the Far East (south of 50° N) - in Primorye, where 1850 species of vascular plants are recorded, of which 460 species are found only in this region, and the floristic lists of individual phytocenoses number more than 100 species. This area has optimal climatic indicators: big amount precipitation and high level sums of positive temperatures. In addition, there is a wide variety of landscapes: river valleys interspersed with hills, mountains and seaside beaches. Species richness in the south of the Russian Far East is determined not only by the current diversity of ecotopes, but also historical processes. In particular, the antiquity of ecosystems, partially preserved from the Holocene, the presence of “small” migration routes, which contributed to the preservation of plant diversity throughout the ancestral territory, the presence of “large” migration routes and land bridges, which ensured the migration of species from the west in the dry late Pleistocene and the replenishment of floras by the Daurian-Mongolian steppe species. In addition, the return of species lost during cold periods as a result of migration from the south from refugia, the presence of shelters from fire contributed to the formation of phytocenoses unique for Russia in terms of species richness.

In contrast to the flora of the south of the Far East, the flora of the northern territories, for example the central part of the Chukotka Peninsula, is much poorer and has 300 species of vascular plants, which is reflected in the floristic poverty of individual plant communities (10-15 species). Here, the main factors limiting species diversity are the severity of the conditions of the Far North and the historically recent settlement of the peninsula with modern vegetation.

Particularly low species richness is typical for plant communities formed under the conditions of some pronounced limiting factor, for example on salt marshes, where species list usually limited to 10 species. The high concentration of soluble salts in the root layer creates very specific conditions for plants that most species cannot tolerate. In such conditions, only organisms that have adaptations to life in high soil salinity can grow. Such plants are called halophytes (from the Greek. halo- salt).

As noted above, an important role in determining the species composition of plant communities belongs to the vegetation itself, which carries out coenotic selection. This is clearly manifested when the phytocenosis is formed under the influence of a powerful edificator, for example spruce (r. Picea). Under the canopy of a spruce forest, in conditions of strong shading and abundant coniferous litter, few species find refuge. And species diversity here is limited to 5-20 species. While in the community of a weaker edificator - birch (p. Betula) - more than 50 species can grow.

Despite the variety of factors that determine species richness, the following statement can be taken as a basis: the closer the conditions are to extreme for plant life, the poorer the flora of plant communities.

• Ipatov V. S., Kirikova L. A. Phytocenology. SPb.: Publishing house St. Petersburg. Univ., 1997, 1999.316 p.
• Urusov V.M., Lobanova I.I., Varchenko L.I. Conifers of the Russian Far East are valuable objects of study, protection, breeding and use. Vladivostok: Dalnauka, 2007. 440 pp.

The species composition of each biocenosis is the result natural selection and long-term evolution against the background of fluctuations in natural regimes and anthropogenic impact. This is a list of species, i.e. floristic and/or faunal list, and ideally soil microflora and invertebrates. Since such an exhaustive or approaching characteristic of the species composition requires the joint work of specialists in different fields, in practice the species composition of the phytocenosis (higher plants, lichens) and some groups of the animal population (birds, reptiles, amphibians, mammals) is most often characterized.

The richest in species are the biocenoses that form in humid tropical climates; the poorest are the biocenoses of arid (desert) regions, polar deserts, and near the nival boundary in the mountains. Only a very limited number of species are able to exist in the close to extreme natural conditions of the Arctic, which determines the relatively monotonous and poor species composition of communities. The general increase in the number of species in biocenoses from the high latitudes of the Arctic and the subnival zone in the mountains to tropical rainforests is one of the striking biogeographical patterns of changes in species diversity.

The number of species in a biocenosis, counted per unit area, is called species richness, which varies among different systematic groups of animals and plants in the same biocenosis. It is highest for flowering plants, mosses and lichens (biocenoses of the tundra, taiga), as well as insects, and much lower for birds and mammals.

The species composition of biocenoses varies significantly depending on the intensity and form of anthropogenic impact. When creating agrocenoses (crops, plantations, gardens), a person ensures that they consist of one or a small number of species. In many forested areas of the world, forest species have undergone a directed change over the centuries in response to the increasing demand for wood. Interesting information changes in the species composition of forests in Central Europe are contained in G. Walter’s book “General Geobotany” (1982).

The number of species in a biocenosis can be assessed in absolute (species mass, number of individuals per unit area) and relative indicators (scores, projective cover). One of the integral estimates of the numerical ratio of species is biomass (phytomass, zoomass) per unit area, established for each type of biocenosis. Using certain abundance estimates, you can get an idea of ​​the absolute or relative dominance of species. It is important to first carry out the comparison within the same size class, since small, stunted species, being numerically dominant, can produce lower biomass. In any biocenosis (with a few exceptions), as a rule, there are several numerically dominant species, which often determine the appearance of the biocenosis. Thus, in spruce forests, in addition to spruce, various green mosses predominate; in different types of spruce forests, sorrel, blueberry and other species predominate.

The species that predominate in numbers are dominants they dominate the biocenosis and constitute its “species” core. For example, in the spruce forests of the Russian Plain, spruce, wood sorrel or other species, green mosses can be identified as dominants;

among the birds - wren, robin, chiffchaff; of mouse-like rodents - red and red-gray voles, etc. However, most of the species in biocenoses are relatively small in number; there are species with a single participation. It should be emphasized that dominance- a relative concept, i.e. dominant is a species that dominates other species in a certain biocenosis. For example, in desert biocenoses, species most often have low numbers and low biomass and, accordingly, the dominants are also characterized by small values.

In addition to dominants, there are also co-dominants(or subdominants), as well as minor, rare and small species. In the most species-rich biocenoses, for example, in humid evergreen tropical forests, almost all species are small in number and the predominant ones cannot be identified here. There are few dominants from the total number of species: a calculation made by V.V. Bykov (1965) for the territory of Eurasia (within the borders of the USSR) showed that out of 20 thousand species of vascular plants, approximately 1,400 species are dominant.

The importance of rare and small species in the biocenosis is great; at their expense, the species richness of the biocenosis is created. Many minor and small species, when conditions change (fluctuations in natural regimes or anthropogenic impact), take the position of dominants when previously dominant species reduce their numbers. Thus, the analysis of quantitative relationships between species and the assessment of the role of dominant and small species in the organization of the biocenosis show that the species composition of the biocenosis is not only the result of selection for habitat, but also the selection of species for possible fluctuations in environmental conditions to maintain the structure of the biocenosis.

Community structure usually called ratio various groups organisms that differ in systematic position, in the role they play in the processes of transfer of energy and matter, in the place occupied in space in the food or trophic web, or in another characteristic that is essential for understanding the patterns of functioning of natural ecosystems.

One of the most important indicators of a community is the species structure.

Species structure a community includes the species composition of its constituent organisms and the quantitative ratio of species populations.

A community is judged primarily by its species diversity And species richness.

Species richness- This general set types of community, which is expressed by lists of representatives different groups organisms.

Species diversity- this is an indicator that reflects not only the qualitative composition of the biocenosis, but also the quantitative relationships of species.

Species diversity is also related to the stability of the community: the greater the diversity, the greater the ability of the community to adapt to changing conditions, be it climate change or other factors.

The number of species in a community depends on many factors, such as its geographic location. It increases noticeably as you move from north to south.

Example:

In a tropical forest on one hectare you can find a hundred species of birds, while in a temperate forest on the same area their number does not exceed a dozen. But in both cases the number of individuals is approximately the same. On islands the fauna is usually poorer than on continents, and the smaller the island and the more distant it is from the mainland, the poorer it is.

The diversity of living organisms is determined by both climatic and historical factors.

Example:

In areas with a mild, stable climate, with abundant and regular rainfall, without severe frosts and seasonal temperature fluctuations, species richness is higher than in areas located in harsh climate zones, such as the tundra or highlands.

Species richness increases with the evolutionary development of the community. The more time has passed since the formation of a community, the higher its species richness.

Example:

In such an ancient lake as Baikal, for example, only \(300\) species of amphipods live.

Most short story have agricultural communities, they are created artificially, the time of their existence is measured in several months. But if a peasant’s field remains unsown and uncultivated for two or three years, it takes on a completely different appearance: the variety of herbs increases, new species of insects, birds, and rodents appear.

In any community, as a rule, there are relatively few species represented by a large number of individuals or large biomass, and relatively many species that are rare. Species with high abundance play a huge role in the life of a community, especially the so-called environment-forming species.

Example:

In forest ecosystems, habitat-forming species include the predominant species woody plants; the conditions necessary for the survival of other species of plants and animals - grasses, insects, birds, animals, small invertebrates of the forest floor, etc. - depend on them.

At the same time, rare species often end up best performance state of the community. This is due to the fact that to maintain life rare species strictly defined combinations are required various factors(for example, temperature, humidity, soil composition, certain types of food resources, etc.). Maintenance necessary conditions largely depends on the normal functioning of ecosystems, so the disappearance of rare species allows us to conclude that the functioning of ecosystems has been disrupted.

Pay attention!

Species diversity is a sign of the stability of communities.

Species diversity can be seen as an indicator of the well-being of a community or ecosystem as a whole. Its decrease often indicates trouble much earlier than a change in the total number of living organisms. In communities with high diversity, many species occupy a similar position, inhabiting the same area of ​​space, performing similar functions in the system of matter-energy metabolism. In such a community, a change in living conditions under the influence of, for example, climate change or other factors can lead to the extinction of one species, but this loss will be compensated by other species close to the extinct one in their specialization. Thus, the greater the species diversity, the more resilient the community is to sudden changes. physical factors or climate.

Sources:

Kamensky A.A., Kriksunov E.A., Pasechnik V.V. Biology. 9th grade // Bustard
Kamensky A.A., Kriksunov E.A., Pasechnik V.V. Biology. General biology(basic level) 10-11 grade // Bustard