Our environment is sometimes taken for granted. Even something unique is forgotten. It seems like a little knowledge and a push in the right direction can make people appreciate environment... So why not start with the wonder that the rainforest is?
Despite the fact that tropical forests cover less than two percent of the entire surface area of the Earth, they are home to about 50% and. They are also found on all continents with the exception of Antarctica. This is very amazing! Now let's see what kind of plants are found here. Out of 40,000 species, in this article you will learn about the 10 most amazing plants rainforest that will thrill your mind and help you get to know amazing nature our planet.
Bananas
Bananas are one of the amazing plants in the rainforest. Even though they look like trees, bananas are not trees, but giant ones. herbaceous plants... After a year, they reach a full height ranging from 3 to 6 m. The flowers eventually develop into fruits and then ripen and are used for human and animal consumption. Banana stems can weigh almost 45 kg and are almost 93% water.
Spreading: Central America, South America, Africa, Southeast Asia, as well as non-tropical regions such as the United States of America, thanks to modern agricultural technology.
Orchid
Orchids are the largest plant family in the world. The species vary greatly in weight and size, with some petals reaching 75 cm in length and inflorescences up to 3 m in length. They can also be of a variety of colors, with the exception of black. Orchids grow on rocks, soil, underground, and other plants, relying on certain insects or birds for pollination.
Spreading: extremely well adapted and grow in Central America, South America and along the Andean mountains.
Coffee
What would you do if you didn't have a cup of coffee in the morning? Surely it would be awful. For coffee, you can thank the rainforest coffee plant. It can grow up to 9 m in height, but is considered a bush or shrub. The coffee fruit resembles grapes and contains two coffee beans inside. It takes six to eight years for a plant to grow, and its lifespan can be up to 100 years.
Spreading: Ethiopia, Sudan, and Latin America grows more than two thirds of the total number of coffee trees on the planet.
Brazilian nut
Rising above all other trees in the rainforest, the Brazil nut can grow to over 50 m in height. The plant is widely known for its nutrient-rich fruits. The outer layer of the fruit is so hard that only agouti - large rodent With sharp teeth may damage it.
Spreading: rainforests of Brazil, Colombia, Venezuela, Ecuador and Peru.
Euphorbia is most beautiful
This beautiful plant is found in tropical forests as a bush or tree. One would think that the red part of the plant is flowers, but in fact they are bracts. Flowers are small yellow inflorescences in the middle of the leaves. Also, to clear up the rumors, they are not venomous, although some believe they are.
Spreading: Mexico and Central America.
Cocoa
The cocoa tree is an evergreen plant whose fruits are pods containing 20 to 60 reddish brown cocoa beans. To obtain 500 g of cocoa, 7 to 14 pods are required. It is very important that the cocoa is harvested correctly.
Spreading: grows below 300 m above sea level in regions that receive about 10 cm of precipitation per month. Cocoa originated in the rainforests of the Amazon Basin and can today be found in southern Mexico.
Brazilian Hevea
This tree can grow up to 40 m in height. Brazilian Hevea is characterized by a milky white juice, commonly called natural rubber, and is used to produce rubber. The tree is used for rubber at the age of six.
Spreading: Brazil, Venezuela, Ecuador, Colombia, Peru and Bolivia.
Heliconia
This genus of plants includes almost 200 species distributed in tropical America... Depending on the species, these plants are capable of growing up to 4.5 m in height. Flowers can be colored in shades of red, orange, yellow and green. The bracts actually hide the flowers of the plant and protect the nectar, so only certain birds, such as hummingbirds, can reach them. Butterflies also love to feast on sweet nectar.
Spreading: Central and South America.
Sapodilla
This strong, wind-resistant tree has extensive root system and bark containing milky juice called latex. Egg-shaped fruits contain a grainy yellow fruit inside and taste like a pear. Considered the finest fruit in Central America, even rainforest mammals love to eat. The first chewing gum was created from sapodilla fruit by the Aztecs!
Spreading: southern Mexico, Belize and northeastern Guatemala.
Bromeliads
Bromeliads include over 2,700 species that grow on the ground, rocks and other plants. These beautiful plants have bright flowers... One of the most famous representatives of the bromeliad family is the sweet, wonderful pineapple fruit! Bromeliads are even sometimes a refuge for frogs, snails and salamanders, where they remain for life.
Spreading: Central and South America. One species is also found in West Africa.
The rainforest is home to many amazing plants, including those that many of us feast on; therefore it is very important to keep this unique. Imagine living without bananas, coffee, chocolate, pineapples and beautiful orchids. This is completely sad!
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Our planet is very different. There are many types of people on it at the same time, the most different types plants and animals. Such species diversity is largely due to the difference in climatic conditions. Indeed, in fact, in the middle European part and in South Africa, the same cultures simply cannot grow, or the same animals can live. There are several classifications according to the type of climate. Most of them are tied to the division of our planet into belts. Today on this page "Popularly about health" we will talk about the tropical climate, or rather clarify which countries are known with tropical climate and tropical forests.
When speaking of a tropical climate, scientists imply that it is characteristic of the tropics. It is a non-arid climate, which maintains an average temperature of more than 18C during all twelve months of the year. Countries with tropical climates experience only slight seasonal temperature fluctuations.
In general, countries with tropical climates can be divided into two groups, depending on rainfall. So the first type of climate is observed in almost all tropical deserts and is a tropical dry climate. The second is typical for oceanic islands located in low latitudes, and is considered a tropical humid climate.
Countries with forests in the tropics
Rainforests are common in a wide belt that surrounds the land along the equator. They grow in many countries, but especially many such territories are found in Brazil, the Democratic Republic of the Congo, Peru, Indonesia, Colombia, Papua New Guinea, Venezuela, Bolivia, Mexico and Suriname. These are exactly the very countries with tropical forests that we are talking about.
Areas with tropical forests are the response of their flora to impact high temperature and abundant moisture. In such territories, constant climatic conditions are maintained.
It is not for nothing that rainforests are often called the largest pharmacy in the world, because they contain a huge number of plants that have medicinal qualities and are used for the preparation of pharmaceutical medicines.
The classic rainforest consists of several layers, due to the struggle of plants for existence. Indeed, a little light penetrates to the ground in such areas, which makes the undergrowth (lower tiers) very limited. But thanks to this feature, tropical forests remain passable for both people and animals.
In the event that the crowns of trees miss sunlight(for example, due to destruction), then everything is very quickly covered with vines, shrubs and medium-sized trees. This is how the jungle is formed.
Such territories are also called "lungs" of the earth, because the humid climate on them facilitates air filtration, since condensate collects on microparticles of pollution. In general, rainforests have a positive effect on the atmosphere.
Let's talk about layers rainforest in a little more detail.
So, arising either new layer consists of individual tree crowns, which reach thirty to seventy meters in height. Such plants receive maximum amount sun rays reaching high level rainforest. Plants of this level are home to many animals and birds.
The upper tier is a fairly dense "ceiling". It consists of evergreen trees that have wide leaves and grow close to each other. It is precisely this layer that interferes with the full penetration of the sun to the lower levels and the ground. The main height of the “ceiling” trees is from twenty to forty meters.
The lower tier of the rainforest is also called the undergrowth. It is located below the upper tier, and it is made up of plants whose height does not exceed twenty meters. In such a layer, only slight air movement is observed and is constantly maintained. high humidity... Due to the lack of sunlight, the undergrowth is constantly shaded. Various ferns, shrubs, grasses, woody vines, as well as low trees usually grow here. So, we figured out the forests and the tropical climate in them.
Some rainforest plants
As for the African rainforests, they grow significant amount legume trees, oil palms, coffee trees and cocoa trees.
Perhaps the most famous representatives of the rainforest are vines. They are made up of strong and large woody stems, which can reach seventy meters or more in length. Of particular interest are the bamboo liana, the healing liana of the strophang, and also the poisonous physiostigma, which also has medicinal qualities.
Many rainforest plants are successfully grown in the greenhouses of our country. To do this, they copy the conditions of the original country with the climate and forests as in the tropics. Also, flower growers cultivate them as indoor plants.
Plants equatorial forests cannot but arouse increased interest not only among specialists, but also among ordinary curious travelers from all over the world. And this is not surprising.
Agree, many of us strive to visit overseas countries precisely for the sake of these exotic representatives of the flora. For example, the plants of equatorial America or Africa are very different from those grasses, flowers, trees and shrubs that we are used to seeing outside our window. hometown... They look, smell and bloom completely differently, which means they evoke mixed emotions. They want to be examined closer, touched and photographed.
Plants of the equatorial forests are a topic that can be talked about for an infinitely long time. This article is aimed at acquainting readers with the most characteristic properties and the habitat of these representatives of the flora world.
general information
First of all, let's try to give a definition to such a concept as wet equatorial forests... Plants, whose habitat are regions with a pronounced equatorial, subequatorial and tropical climate, inhabit given view natural area... It is worth paying attention to the fact that in this case, not only grasses, but also numerous trees and shrubs can be attributed to various kinds of flora.
At first glance, it is difficult even to imagine, but here there is observed up to 2000, or even 10,000 mm of precipitation per year.
These land areas are characterized by enormous biodiversity; it is here that 2/3 of all plants and animals of our planet live. By the way, not everyone knows that millions of species have not yet been described.
There is not enough light on the lower tier in damp tiers, but the undergrowth, as a rule, is formed weak, so a person can easily move on it. However, in the event that for some reason the deciduous canopy is absent or weakened, the lower tier can quickly become covered with impassable thickets of vines and intricate trees. This is called the jungle.
Equatorial forest climate
Animals and plants, as we have said, are diverse. This is due to the prevailing climate, which means that it needs to be discussed in more detail.
This zone stretches along the equator with an offset to the south. The average temperature is 24-28 degrees all year round. The climate is quite hot and humid, although the seasons are implicitly expressed.
This territory belongs to the region and precipitation falls here evenly throughout the year. Such climatic conditions favor the development of evergreen vegetation, which is characterized by the so-called compound forest structure.
The flora of the equatorial territories of the planet
As a rule, moist evergreen forests, located in narrow strips or peculiar spots along the equator, are diverse and include a huge number of species. It is difficult to imagine that today there are more than a thousand of them in the Congo Basin and on the coast alone.
Plants of the equatorial forests of the upper tier are represented by giant ficuses and palms, of which there are more than 200 species. In the lower ones, mainly bananas and tree ferns grow.
The largest plants are often entwined with vines and flowering orchids. By the way, it is worth noting that sometimes in equatorial forests there are up to six tiers. Among the plants there are also epiphytes - mosses, lichens, ferns.
But in the depths of the forest you can find largest flower our planet - Rafflesia Arnoldi, the transverse diameter of which reaches 1 meter.
Fauna of the equatorial forest
Hardly anyone will be surprised if we note that the fauna of the equatorial forests is primarily rich in monkeys. Especially often in huge numbers there are monkeys, chimpanzees, gorillas, howlers and bonobos.
Of the terrestrial inhabitants, you can often find small ungulates, for example, in Africa, tourists often admire okapi, African deer and other unusual animals. The most common jungle predators South America of course, the jaguar and the puma are considered. But in the African tropics, the hosts are fast leopards and huge tigers.
Thanks to wet conditions The equatorial forest environment is home to many frogs, lizards and insects. Among the birds, the most common are hummingbirds, parrots and toucans.
As for reptiles, who does not know about the pythons of Africa and Asia or the anaconda from the Amazon jungle? In addition, in equatorial forests are common Poisonous snakes, alligators, caimans and others not less dangerous representatives fauna world.
What happens if plants in equatorial forests are destroyed?
During the clearing of the equatorial forest, a person, sometimes without realizing it, destroys the habitat of many animals and takes food from the termites. In addition, this forest also holds back the onset of deserts that are destructive for all living things.
But that's not all. The fact is that humid equatorial forests, although they occupy a relatively small part of the Earth, are the so-called green lungs our planet. It is here that about 1/3 of the Earth's oxygen is produced, therefore, the destruction of the equatorial forest will cause irreversible environmental impact, including an increase in the content The latter, in turn, will lead to an increase in the average temperature, increase the likelihood and, therefore, entail the subsequent flooding of many fertile lands.
Flora and fauna. This is the most vibrant natural area.
Two-thirds of all animal and plant species on the planet live in tropical rainforests. It is estimated that millions of animal and plant species have not yet been described. These forests are sometimes called " jewels of the earth" and " the largest pharmacy in the world", insofar as a large number of natural health remedies have been found here. They are also called “ lungs of the earth”, However, this statement is controversial, since it has no scientific basis, since these forests either do not produce oxygen at all, or produce very little of it. But it should be borne in mind that a humid climate promotes effective air filtration, due to the condensation of moisture on microparticles of pollution, which generally has a beneficial effect on the atmosphere.
Undergrowth formation in tropical rainforests is severely limited in many places due to the lack of sunlight in the lower tier. This allows humans and animals to move through the forest. If for any reason deciduous canopy is missing or weakened, the lower tier is quickly covered with dense thickets of vines, shrubs and small trees - this formation is called a jungle.
Spreading
Distribution of tropical rainforests in the world.
The largest tropical rainforests exist in the Amazon Basin (Amazon Rainforest), in Nicaragua, in the southern part of the Yucatan Peninsula (Guatemala, Belize), in much of Central America (where they are called "selva"), in equatorial Africa from Cameroon to Democratic Republic of the Congo, in many parts of Southeast Asia from Myanmar to Indonesia and Papua New Guinea, in the Australian state of Queensland.
general characteristics
For tropical rainforest are characteristic:
- variety of flora,
- the presence of 4-5 tree layers, the absence of shrubs, a large number of vines
- predominance evergreen trees with large evergreen leaves, poorly developed bark, buds, not protected by kidney scales, in monsoon forests - deciduous trees;
- the formation of flowers, and then fruits directly on the trunks and thick branches
Flora
Trees in tropical rainforests have several general characteristics which are not observed in plants of less humid climates.
The base of the trunk in many species has wide, woody ridges. Previously, it was assumed that these protrusions help the tree to maintain balance, but now it is believed that water with dissolved nutrients flows down these protrusions to the roots of the tree. Broad leaves are also common in trees, shrubs, and grasses. lower tiers forests. Tall young trees, which have not yet reached the upper tier, also have wider foliage, which then decreases with height. Wide leaves help plants better absorb sunlight under the forest's tree edges, and they are protected from the wind from above. The top-tier leaves that form the canopy are usually smaller and heavily indented to reduce wind pressure. On the lower floors, the leaves are often tapered at the ends so that this facilitates rapid drainage of water and prevents the growth of microbes and moss on them, which destroy the leaves.
The tops of trees are often very well connected with each other with the help of vines or epiphytic plants that are attached to them.
Other characteristics of tropical rainforest are unusually thin (1–2 mm) tree bark, sometimes covered with sharp thorns or thorns; the presence of flowers and fruits growing directly on tree trunks; big variety juicy fruits that attract birds, mammals and even fish that feed on dust.
Fauna
In humid tropical forests, there are edentulous (families of sloths, anteaters and armadillos), broad-nosed monkeys, a number of families of rodents, bats, llamas, marsupials, several orders of birds, as well as some reptiles, amphibians, fish and invertebrates. Many animals with prehensile tails live on the trees - chain-tailed monkeys, dwarf and four-toed anteaters, possums, chain-tailed porcupines, sloths. There are a lot of insects, especially butterflies (one of the richest fauna in the world) and beetles; many fish (as many as 2000 species - this is approximately one third of the world's freshwater fauna).
The soil
Despite the lush vegetation, the quality of the soil in these forests leaves much to be desired. Rapid rotting caused by bacteria interferes with the accumulation of the humus layer. The concentration of iron and aluminum oxides due to laterization soil (the process of decreasing the content of silica in the soil with a simultaneous increase in iron and aluminum oxides) stains the soil bright red and sometimes forms deposits of minerals (for example, bauxite). On young formations, especially of volcanic origin, the soils can be quite fertile.
Rainforest levels
The rainforest is divided into four main levels, each of which has its own characteristics, has a different flora and fauna.
Topmost level
This layer consists of a small amount of very tall trees reaching a height of 45-55 meters ( rare species reach 60 - 70 meters). Most often, the trees are evergreen, but some shed their foliage during the dry season. Such trees must withstand harsh temperatures and strong winds... This level is inhabited by eagles, bats, some types of monkeys and butterflies.
Crowns level
The crown level is formed by most of the tall trees, usually 30 - 45 meters high. It is the densest level known in all terrestrial biodiversity, a more or less continuous layer of foliage formed by neighboring trees.
According to some estimates, the plants of this layer make up about 40 percent of all plant species on the planet - perhaps half of the entire flora of the Earth can be found here. The fauna is similar to the upper level, but more diverse. It is believed that a quarter of all insect species live here.
Scientists have long suspected the diversity of life at this level, but only recently have developed practical methods research. It wasn't until 1917 that an American naturalist William Beade(eng. William beede) stated that "another continent of life remains unexplored, not on Earth, but 200 feet above its surface, spreading over thousands of square miles."
Real exploration of this layer did not begin until the 1980s, when scientists developed methods to reach canopy, such as shooting ropes at treetops with crossbows. Canopy research is still in its early stages. Other research methods include travel balloons or aircraft. The science of treetop access is called dendronautics. Dendronautics).
Average level
Between the edges of the canopy-level trees and the forest floor, there is another level, called the middle or sub-ceiling... It is home to a number of birds, snakes and lizards. The life of insects at this level is also very extensive. The leaves in this layer are much wider than at the crown level.
Forest litter
In Central Africa, in the Virunga Primary Rainforest of Mount Virunga, the illumination at ground level is 0.5%; in the forests of southern Nigeria and in the Santarema region (Brazil) 0.5-1%. In the north of Sumatra, in the dipterocarp forest, the illumination is about 0.1%. Under such conditions, only some mosses grow on rotten trunks and disc-shaped roots; at 0.2% illumination, selaginella and liver mosses begin to occur; at 0.25-0.5% some types Hymenophyllaceae, Commelinaceae, Zingiberaceae, Rubiaceae, lymphoids and begonias. Far from the banks of rivers, swamps and open spaces, where dense, low-growing vegetation grows, forest floor relatively free from plants. At this level, you can see rotting plants and animal remains, which quickly disappear thanks to the warm, humid climate that promotes rapid decomposition.
Human exposure
Contrary to popular belief, tropical rainforests are not large consumers of carbon dioxide and, like other mature forests, are neutral to carbon dioxide. Recent research suggests that most rainforests, on the other hand, produce carbon dioxide. However, these forests play a significant role in the turnover carbon dioxide, since they are its established basins, and the deforestation of such forests leads to an increase in the content of carbon dioxide in the Earth's atmosphere. Rainforests also play a role in cooling the air that passes through them. So tropical rainforest is one of the most important ecosystems of the planet, the destruction of forests leads to soil erosion, a reduction in flora and fauna species, and a shift in the ecological balance by large territories and on the planet as a whole.
Tropical rainforest are often reduced to plantations of cinchona and coffee trees, coconut trees, and rubber plants. In South America for tropical rainforest unsustainable mining is also a serious threat.
Literature
- M. B. Gornung. Constantly humid tropics. M., "Thought", 1984.
see also
Notes (edit)
| Natural areas | |
|---|---|
| Land | Arctic Desert | Antarctic Desert | Tundra | Forest tundra | Coniferous forest - Taiga | Subtaiga | Mixed forest | Deciduous forest: broadleaf forest and small-leaved forests | Forest-steppe | Steppe | Semi-desert | Desert | Savannah | Subtropical forest | Rain forest | Alternating wet forest | Tropical rainforest - |
A tropical forest- a forest common in the tropical, equatorial and subequatorial belts between 25 ° N sh. and 30 ° S. sh. Rainforests are found in a wide belt that surrounds the Earth at the equator and is torn apart only by oceans and mountains.
The general circulation of the atmosphere comes from a zone of high atmospheric pressure in the tropics, the evaporated moisture is transported in the same direction to the low pressure zone in the equator. This leads to the existence of a humid equatorial belt and a dry tropical one. Between them is the subequatorial belt, in which moisture depends on the direction of the wind (monsoon), which depends on the season.
The vegetation of tropical forests is very diverse, depending mainly on the amount of precipitation and its distribution over the seasons. In the case of abundant (more than 2000 mm) and their more or less uniform distribution, humid tropical evergreen forests develop. With distance from the equator, forests appear, in which moisture depends on the season: the rainy period is replaced by a dry one. These are winter-green, variable-humid tropical forests with leaves falling off during a drought. Further, these forests are replaced by savanna forests. At the same time, in Africa and South America, monsoon and equatorial forests are replaced by savanna forests from west to east. In an even more arid climate, forest stands are thinned out, savanna forests are replaced by xerophilic thorny forests and thickets of shrubs.
Distribution of tropical forests
It will immediately become clear where the rainforests grow, if we explain that they seem to "encircle" the planet along the Equator. They are located in the humid equatorial, dry tropical, temperate subequatorial zones, representing a clear line, interrupted only by mountains and oceans. Vegetation changes depending on the air temperature and the amount of precipitation. Rainy areas are covered with evergreen flora, drier regions are typical deciduous plants, and then there are savannah forests. In both South America and Africa, there are monsoon forests in the west, savanna forests in the east, and equatorial forests in the middle.
Forest levels
The description of the rainforest will be clearer if it is divided into tiers. There are four main levels. The topmost one is evergreen trees up to 70 m tall, they have green caps mainly only on top, but below there are bare trunks. These giants can easily withstand hurricanes, temperature drops, sheltering the rest of the tiers from bad weather. The main owners here are eagles, butterflies, the bats... Further there is a forest canopy consisting of 45-meter trees. The level of the crowns is considered the most diverse, about 25% of all insect species live here. Scientists agree that 40% of all plant species on the planet are located on this tier, although it has not been fully studied.
Rainforest classification
The main groups of rainforest formations are rainforest, or wet, and seasonal.
- Rainforests - common in equatorial belt, are characterized by abundant precipitation (2000-7000 mm, sometimes even up to 12000 mm) and their relatively uniform distribution throughout the year with practically unchanged average temperature air (24-28 ° C). Main regions of distribution: South America, Central Africa, Southeast Asia and Australia. Tropical rainforests are considered the center of evolutionary activity, a place where new species form, spreading to other regions. They are the most ancient type of vegetation, practically unchanged since the Tertiary period. The main groups of tropical rainforests are moist evergreen mountain forests, tropical swamp forests, rainforests, tropical lowland forests, mangroves.
- Mangroves are common in the intertidal zone of tropical coasts and, if favored warm currents, then also along the coast in the temperate climatic zone. They grow in places free of water at low tide and flooded at high tide.
- Tropical mountain evergreen forests usually grow above 1500-1800 m, where air temperatures drop to 10-12 ° and below, which prevents many organisms from developing. The relative preservation of these forests, which are of significant importance in stabilization natural conditions(water protection, anti-erosion, etc.), contributes to their low economic value, associated with the difficulties of development under the conditions of the relief.
- Swamp forests occupy a noticeably smaller area than non-flooded plain forests. According to their properties, they are close, although they have enough differences. Distributed in the same plains, they create a landscape mosaic of tropical forests.
- Seasonal rainforests grow in areas where, despite good moisture (2500-3000 mm), there is a dry period. The amount of precipitation and the duration of the dry period in different forests is not the same, among them there are evergreen seasonal forests(e.g. Australian eucalyptus), semi-evergreen forests(deciduous species are presented in the upper tier, in the lower - evergreen), light sparse forests (the floristic composition is poor, sometimes it is represented by one species). Deciduous seasonal rainforests are divided into monsoon forests and savanna forests.
- Monsoon forests grow in the monsoon area, the dry season lasts about 4-5 months. They are located in South and Southeast Asia, including Hindustan, Indochina, the Malacca Peninsula, in the northeast of Java. Forests of this type also grow in the West Indies and Central America (Trinidad Island, Costa Rica) and West Africa.
- Savannah forests are common in tropical areas with a distinct dry season and less annual precipitation than in the belt of closed forests. Distributed throughout most of Cuba and other islands Caribbean, in many parts of South America, East and Central Africa and here and there in India, China and Australia.
- Thorny xerophilous forests and shrubs grow in areas with even less rainfall, such as caatinga, with a dry season of at least 6 months.
Seasonal rainforest vegetation
In monsoon forests, three main groups of plant communities can be distinguished.
- V mixed forests dominated by Terminalia, Dalbergia, Albizia and others, the undergrowth consists of bamboos and small palms.
- In teak forests - teak tree (large tectone), deciduous Acacia lencophloea and Albizzia procera and evergreen Butea frondosa, Scheichera trijuda, etc.
- Forests from Shoreya gigantic, undergrowth from Terminalia, Sterculia, etc.
Grow in India ebony trees, Indian laurel. Lianas and epiphytes, although not as numerous as in evergreens, are more numerous than in savanna forests. The forest canopy in monsoon forests is thinner in comparison with humid tropical forests, therefore, the grass cover in them is closed. The grasses are mostly annual, with wild sugarcane prevailing in the driest areas.
For the upper tier of forests of this type in West Africa triplochiton (Triplochiton scleroxylon) is especially characteristic.
For savannah forests, deciduous trees from the legume family are typical, the crown of which is usually flat, umbrella-shaped. The trees are up to 18 m high. In places where the trees are 3-4.5 m high, during the rainy season, the grasses may be higher than the trees. Grains form the basis of the herbaceous cover.
In thorny xerophilous forests, there are trees with scaly leaves and shrubs with green stems without leaves. Plants are often covered with thorns, and stem and root tissues are capable of storing water.
Rainforest herbs
Unbelievably beautiful, bright, with unusual appearance birds. Each separate part of the world can boast of its own kind of birds. For example, in the tropics of Asia, there are turachi, outward appearance they resemble partridges, only slightly larger. They run fast, so in case of danger they do not take off, but flee with all their might. The forests are also home to bush chickens, pheasants, and regal peacocks. In the American tropics, you can find tinama - a poorly flying bird with short but very strong legs. Well, how can you not remember the bright, funny and talkative parrots, without which the tropics are not tropics. In addition, variegated pigeons, trogons, woodpeckers, flycatchers, hornbills and others live on the equator.
Animal world
In terms of the number of species, tropical forests significantly exceed the forests of temperate and cold countries, the fauna of tropical rain forests is the richest, nevertheless, the number of representatives of each a separate kind they are small.
Typically, tropical forest animals live in trees and in crowns. Representatives of mammals are monkeys, flying squirrels, sloths, spiny-tailed squirrels, needle-hairs, some insectivores, carnivores, and so on. Birds are represented by parrots, woodpeckers, toucans, hummingbirds, craxes, hoatsins and others; examples of reptiles are chameleons, tree snakes, some geckos, iguanas, agamas; amphibians - some frogs. Many reptiles are poisonous.
In tropical rainforests, due to a lack of light, the undergrowth and grass cover is poor, therefore terrestrial species there is little in them. They are represented by tapirs, rhinos, bakers, hippos. Areal large mammals, including elephants, giraffes, buffaloes are seasonal rainforests
Invertebrates are very diverse, they can be quite large, stand out for the richness of shapes and colors, among them ants, centipedes, butterflies and others.
Ecology
The result of using slash-and-burn agriculture in Namdapha National Park (India)
Tropical forests are extremely important for the biosphere of the planet; they are the habitat of almost half of all biological species inhabiting it, over 80% of all plant species. The area of tropical forests is half of the forest area of the Earth. They produce 69% of all net primary forest production in the world. Rainforests evaporate about 9% of the water entering the atmosphere. Despite the high biological productivity(up to 3500 g / m2 per year) and large leaf litter, the supply of litter in them is much less than in temperate forests... This is due to both the intensity of leaching in rain forests and the general intensity of decomposition, with mushrooms and termites processing over 90% of the annual growth. plant matter... The rest is eaten by herbivores, which, in turn, serve as a food source for predators.
Half of the primary rainforests have disappeared - either secondary forests have grown, or grassy communities remain, which may turn into deserts. The greatest concern is the decline in tropical rain forests. Ecosystems of the seasonally humid tropics have adapted to both seasonal changes and to interannual differences in the duration of dry and wet periods, therefore they are more resistant to anthropogenic impacts. The process is aggravated by the fact that when deforestation occurs in just 1-2 years, nutrients are washed out from the soil into the subsoil. The main reasons for the decline in tropical forest area are:
- slash and burn agriculture,
- burning forests for pastures,
- logging.
Many international organizations, for example IUCN, UN FAO, UNEP, recognize the importance of tropical forests for the planet's biosphere and contribute to their conservation. About 40 million hectares of protected areas have been created here, including the Salonga and Maiko National Parks (Zaire); Jau, Amazonian (Brazil); Manu (Peru), Canaima (Venezuela). It is believed that in order to preserve tropical forest ecosystems, protected areas should cover at least 10% of the forest area.
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