Flora of the variable rain forests of South America. Forests of South America

The continent of South America is located in all geographical zones, with the exception of subantarctic and antarctic. The wide northern part of the continent lies at low latitudes, so the equatorial and subequatorial belts are most widespread. Distinctive feature The continent is characterized by the widespread development of forest natural zones (47% of the area). 1/4 of the planet’s forests are concentrated on the “green continent”(Fig. 91, 92).

South America gave humanity many cultivated plants: potatoes, tomatoes, beans, tobacco, pineapple, hevea, cocoa, peanuts, etc.

Natural areas

In the equatorial geographical zone there is a zone wet equatorial forests , occupying Western Amazonia. They are named by A. Humboldt hylea, and by the local population - the village. Wet equatorial forests South America- the richest forests in terms of species composition on Earth. They are rightfully considered the “gene pool of the planet”: they contain more than 45 thousand plant species, including 4000 woody ones.

Rice. 91. Endemic animals of South America: 1- giant anteater; 2- hoatzin; 3 - lama; 4 - sloth; 5 - capybaras; 6 - battleship

Rice. 92. Typical trees of South America: 1 - Chilean araucaria; 2 - wine palm; 3 - chocolate tree (cocoa)

There are flooded, non-flooded and mountain hylia. In river floodplains, flooded with water for a long period, impoverished forests of low trees (10-15 m) with breathing and stilt roots grow. Cecropia (“ant tree”) predominates; giant Victoria regia swim in the reservoirs.

In elevated areas, rich, dense, multi-tiered (up to 5 tiers) flood-free forests are formed. The solitary ceiba (cotton tree) and the Brazil nut-bearing bertolecia grow to a height of 40-50 m. The upper tiers (20-30 m) are formed by trees with valuable wood (rosewood, pau brazil, mahogany), as well as ficus and hevea, from the milky juice of which rubber is obtained. In the lower tiers, under the canopy of palm trees, chocolate and melon trees grow, as well as ancient plants on Earth - tree ferns. The trees are densely intertwined with lianas; among the epiphytes there are many brightly colored orchids.

Mangrove vegetation, poor in composition (nipa palm, rhizophora), is developed near the coast. Mangroves- these are thickets of evergreen trees and shrubs of the swampy zone of tidal seas of tropical and equatorial latitudes, adapted to salt water.

Moist equatorial forests form on red-yellow ferrallitic soils, poor nutrients. Falling leaves in hot and humid climates quickly rot, and the humus is immediately absorbed by plants, without having time to accumulate in the soil.

Hylaea animals are adapted to life in trees. Many have a prehensile tail, such as the sloth, opossum, prehensile-tailed porcupine, broad-nosed monkeys(howler monkeys, arachnids, marmosets). The ponds are home to peccary pigs and tapirs. There are predators: jaguar, ocelot. There are numerous turtles and snakes, including the longest one - the anaconda (up to 11 m). South America is the “continent of birds”. Hylea is home to macaws, toucans, hoatzins, tree hens and the smallest birds - hummingbirds (up to 2 g).

The rivers are teeming with caimans and alligators. They are home to 2,000 species of fish, including the dangerous predatory piranha and the largest in the world, the arapaima (up to 5 m in length and weighing up to 250 kg). The electric eel and the freshwater inia dolphin are also found.

Zones stretch across three geographical zones variable-humid forests . Subequatorial variable-humid forests occupy eastern part The Amazonian lowland and the adjacent slopes of the Brazilian and Guiana plateaus. The presence of a dry period causes the appearance of deciduous trees. Among the evergreens, cinchona, ficus, and balsa, which have the lightest wood, predominate. In tropical latitudes on a humidified eastern outskirts Rich evergreens grow on the mountain red soils of the Brazilian plateau rainforests, close in composition to equatorial ones. The southeast of the plateau on red soils and yellow soils is occupied by sparse subtropical moist forests. They are formed by Brazilian araucaria with an undergrowth of yerba mate (“Paraguayan tea”) shrubs.

Zone savannas and woodlands distributed in two geographical zones. In subequatorial latitudes it covers the Orinoco Lowland and the interior regions of the Brazilian Plateau, and in tropical latitudes it covers the Gran Chaco plain. Depending on the moisture content, wet, typical and desert savannas are distinguished. Under them, red, brown-red and red-brown soils develop, respectively.

The tall grass wet savanna of the Orinoco River basin is traditionally called Llanos. It is flooded for up to six months, turning into an impassable swamp. Grains and sedges grow; Of the trees, the Mauritius palm dominates, which is why the llanos is called the “palm savanna.”

On the Brazilian plateau, savannas were called campos. Wet shrub-tree savanna occupies the center of the plateau, while typical grassy savanna occupies the south. Low-growing shrubs grow against the background of cereal vegetation (bearded grass, feather grass). The trees are dominated by palms (wax palms, oil palms, vine palms). The arid northeast of the Brazilian Plateau is occupied by desert savanna - caatinga. This is a woodland of thorny bushes and cacti. There is a bottle-shaped tree that stores rainwater - the Bombax cottonweed.

Savannas continue into tropical latitudes, occupying the Gran Chaco plain. Only in tropical woodlands is the quebracho ("break the axe") tree found, with hard and heavy wood that sinks in water. The savannas contain plantations of coffee, cotton, and bananas. Dry savannas are an important area for grazing.

Savannah animals are characterized by a protective brown coloration (spice-horned deer, red nose, maned wolf, rhea ostrich). Rodents are abundantly represented, including the largest in the world, the capybara. Many Hylaea animals (armadillos, anteaters) also live in savannas. Termite mounds are ubiquitous.

In the Laplata Lowland south of 30° S. w. are being formed subtropical steppes . In South America they were called pump. It is characterized by rich forb-grass vegetation (wild lupine, pampas grass, feather grass). The chernozem soils of the pampa are very fertile and therefore heavily plowed. The Argentine pampa is the main growing area for wheat and forage grasses in South America. Animal world Pampa is rich in rodents (tuco-tuco, viscacha). There are Pampas deer, Pampas cat, puma, and rhea ostrich.

Semi-deserts and deserts South America extends across three geographical zones: tropical, subtropical and temperate. In the west of the tropics, tropical deserts and semi-deserts stretch in a narrow strip along the Pacific coast and on the high plateaus of the Central Andes. This is one of the driest areas on Earth: in the Atacama Desert it may not rain for years. On the infertile gray soils of coastal deserts, dry cereals and cacti grow, receiving moisture from dew and fog; on the gravelly soils of high-mountain deserts there are creeping and cushion-shaped grasses and thorny shrubs.

The fauna of tropical deserts is poor. Inhabitants of the highlands - llamas, spectacled bears, possessing valuable fur chinchilla. There is the Andean condor - the largest bird in the world with a wingspan of up to 4 m.

To the west of the pampa, in a continental climate, they are common subtropical semi-deserts and deserts. Light forests of acacias and cacti are developed on gray soils, and solyankas are found on salt marshes. In the harsh temperate latitudes of lowland Patagonia, dry cereals and thorny shrubs grow on brown semi-desert soils.

The southwestern edge of the continent in two zones is occupied by forests natural areas. In the subtropics, under Mediterranean climate conditions, a zone is formed dry hard-leaved forests and shrubs . The coast and slopes of the Chilean-Argentine Andes (between 28° and 36° S) are covered with forests of evergreen southern beech, teak, persea on brown and gray-brown soils.

Located further south wet evergreen And mixed forests . In the northern Patagonian Andes, moist evergreen forests grow on mountain brown forest soils in a subtropical humid climate. With abundant moisture (more than 3000-4000 mm of precipitation), these rain forests are multi-layered and rich, for which they received the name “subtropical hylea”. They consist of evergreen beeches, magnolias, Chilean araucaria, Chilean cedar, South American larch with a rich understory of tree ferns and bamboos. In the south of the Patagonian Andes, in a temperate maritime climate, mixed forests of deciduous beech and coniferous podocarpus grow. Here you can find puda deer, Magellanic dog, otter, and skunk.

High Andean region occupies a vast territory with a well-defined altitudinal zone, most fully manifested in equatorial latitudes. Common up to an altitude of 1500 m hot belt- hylea with an abundance of palms and bananas. Above the 2000 m mark there is a temperate zone with cinchona, balsa, tree ferns and bamboos. A cold belt extends to the 3500 m mark - a high-mountain hylea of ​​low-growing crooked forests. It is replaced by a frost belt with high-mountain meadows of paramos cereals and low-growing shrubs. Above 4700 m there is a belt of eternal snow and ice.

Bibliography

1. Geography 8th grade. Tutorial for 8th grade institutions of general secondary education with Russian as the language of instruction / Edited by Professor P. S. Lopukh - Minsk “People's Asveta” 2014

The tundra occupies such areas as the coastal outskirts of Greenland, the western and northern outskirts of Alaska, the coast of Hudson Bay, and some areas of the Newfoundland and Labrador peninsulas. In Labrador, due to the severity of the climate, the tundra reaches 55° N. sh., and in Newfoundland it drops even further south. The tundra is part of the circumpolar Arctic subregion of the Holarctic. The North American tundra is characterized by permafrost, highly acidic soils, and rocky soils. Its northernmost part is almost completely barren or covered only with mosses and lichens. Large areas are occupied by swamps. In the southern part of the tundra, a rich herbaceous cover of grasses and sedges appears. Some dwarf tree forms are characteristic, such as creeping heather, dwarf birch (Betula glandulosa), willow and alder.

Next comes the forest-tundra. It reaches its maximum size west of Hudson Bay. Woody forms of vegetation are already beginning to appear. This strip forms the northern limit of forests in North America, dominated by species such as larch (Larix laricina), black and white spruce (Picea mariana and Picea canadensis).

On the slopes of the Alaska mountains, lowland tundra, as well as on the Scandinavian Peninsula, gives way to mountain tundra and char vegetation.

In terms of species, tundra vegetation North America almost no different from the European-Asian tundra. There are only some floristic differences between them.

Coniferous forests temperate zone occupy most of North America. These forests form the second and last vegetation zone after the tundra, which stretches across the entire continent from west to east and is a latitudinal zone. Further to the south, latitudinal zonality is preserved only in the eastern part of the continent.

On the Pacific coast, taiga is distributed from 61 to 42° N. sh., then it passes through the lower slopes of the Cordillera and then spreads to the plain to the east. In this area, the southern border of the zone coniferous forests rises north to a latitude of 54-55° N, but then it descends back to the south to the territories of the Great Lakes and the St. Lawrence River, but only its lower reaches.<

Coniferous forests along the line from the eastern slopes of the Alaska mountains to the Labrador coast are distinguished by significant uniformity in the species composition of the species.

A distinctive feature of the coniferous forests of the Pacific coast from the forest zone of the east is their appearance and composition of species. So, the forest zone of the Pacific coast is very similar to the eastern regions of the Asian taiga, where endemic coniferous species and genera grow. But the eastern part of the continent is similar to the European taiga.

The “Hudson” eastern taiga is characterized by the predominance of fairly developed coniferous trees with a high and powerful crown. This composition of species includes such endemic species as white or Canadian spruce (Picea canadensis), Banks pine (Pinus banksiana), American larch, balsam fir (Abies balsamea). From the latter, a resinous substance is extracted, which finds its way into technology - Canada balsam. Although conifers predominate in this zone, there are still many deciduous trees and shrubs in the Canadian taiga. And in burnt areas, of which there are many in the Canadian taiga region, even deciduous trees predominate.

Deciduous tree species in this coniferous zone include: aspen (Populus tremuloides), balsam poplar (Populus balsamifera), paper birch (Betula papyrifera). This birch tree has white and smooth bark, which the Indians used to build their canoes. It is characterized by a very diverse and rich undergrowth of berry bushes: blueberries, raspberries, blackberries, black and red currants. This zone is characterized by podzolic soils. In the north they turn into soils of permafrost-taiga composition, and in the south they become soddy-podzolic soils.

The soil and vegetation cover of the Appalachian zone is very rich and diverse. Here, on the slopes of the Appalachians, rich broadleaf forests grow in species diversity. Such forests are also called Appalachian forests. These forests are very similar to the genera of East Asian and European forests, in which the dominant role is dominated by endemic species of noble chestnut (Castanea dentata), may beech (Fagus grandifolia), American oak (Quercus macrocarpa), red sycamore (Platanus occidentalis). A characteristic feature of all these trees is that they are very powerful and tall trees. These trees are often covered with ivy and wild grapes.

Vietnam

The Socialist Republic of Vietnam is located in Southeast Asia, on the eastern coast of the Indochina Peninsula. It occupies an area of ​​331,600 km 2, which is comparable to the territory of Germany. Vietnam borders China in the north, Laos in the west, Cambodia in the south-west, and the South China Sea in the east. Vietnam owns two large archipelagos - Hoang Sa and Truong Sa and a large number of islands. Three quarters of the country's territory is mountainous; there are two fertile deltas of the main waterways of the country, the Mekong (Fig. 2.73) and Red rivers. The length of Vietnam's coastline excluding islands is 3,444 km. Population - 92.477 million people (2013 data).

The climate, according to the Köppen classification, belongs to the types Aw (tropical savannah climate on the plains of the south of the country) and Cwa-Am (warm monsoon climate in the mountainous north).

Vietnam's economy has been developing rapidly since 1990, when the country, following the example of China, began to combine state and private ownership. GDP growth varies between 5.3-8.5%.

There are 13 large rivers and about 3,500 rivers with a length of at least 10 km flowing through Vietnam. Water resources have become an important factor in ensuring food and energy security, as well as in the industrialization and modernization of the country. At the end of the 20th century, Vietnam took first place in the world in terms of rice exports (Vietnam..., 1993) (Fig. 2.74-2.78).

Water resources are also a decisive factor in increasing the production of other agricultural and industrial crops such as tea, coffee, black pepper, etc. Currently, 70% of the water used for agricultural production comes from the Red and Mekong rivers. However, the country faces numerous challenges in the use of water resources.

The Mekong is one of the largest rivers in the world: its length is 4350 km, and its area is 795 thousand km 2. Powered by rain, snow and glaciers. Its basin is home to 250 million people from several countries (Fig. 2.73).

Rice. 2.74

Valley type of settlement. Fields and villages are located in the valleys of small rivers

The Mekong basin ranks second in the world in terms of biological diversity after the Amazon. The Mekong flows through the territory of 4 countries: China, Laos, Cambodia and Vietnam. The state borders of Myanmar (Burma) and Thailand run along the right bank of the river. The cooperation of the countries to which this river is directly related has its own name among experts - “the spirit of the Mekong.” Since 1957, this cooperation has taken place within the framework of the River Commission. Mekong (Rysbekov, 2009; FB.ru: http://fb.ru/article/222437/mekong).

Rice. 2.75

Rice fields of Mu Kan Chai District, Yen Bai Province

Rice. 2.76

Rice. 2.77

Rice. 2.78

On the territory of Vietnam there is only a relatively small section (200 km long) of the lower reaches of the river. The Mekong, which is a delta of two wide branches and many smaller channels (Fig. 2.79, 2.80). There are many canals dug here. The delta, with an area of ​​70 thousand km 2, is home to 17 million Vietnamese. The climate within the delta is subequatorial monsoon. Average annual temperature 27°C; The year is divided into two seasons - wet and dry.

Rice. 2.79

The economies of the Mekong Delta provinces are based on agriculture (rice cultivation (Figures 2.81, 2.82)) and aquaculture. An important role in the delta is played by artificial canals, which are transport arteries and places for breeding aquatic products. The most famous canal, Vinh Te, is 87 km long and 40 to 60 m wide. It was dug by hand using shovels and hoes over 5 years, from 1819 to 1824, during the reign of the Nguyen royal dynasty.

The fishing fleet includes more than 25 thousand vessels of various tonnage. More than 1 million tons of fish (pangasius), about 300 thousand tons of saltwater shrimp and a large number of other species of fish, arthropods and mollusks are grown annually. About 200 factories have been built to process seafood. Tourism has been developing intensively in the last two decades.

Fig.2.80

Rice. 2.81

Rice. 2.82

The role of water resources in providing food to the population of Eurasia. Based on the review of the most common types of agricultural land in Eurasia, we will try to assess the role of water resources in solving the food problem on this continent. The world's population is projected to increase to 9 billion by 2050. At the beginning of section 2.2, we outlined one of the food programs proposed by J. Foley (2014), which includes five steps. This program aims to double food production by 2050, but does not address the issue of water security. In table 2.4. The "steps" of the Foley program are numbered 1-5. The last column shows our estimate of the program's water supply as a percentage of the volume required to double food production.

The “first step” - stabilization of the area of ​​agricultural land is accepted as feasible in all territories considered as a necessary initial condition for the implementation of the Foley program. The “second step” (continuation of the “green revolution”) is possible on irrigated lands of countries with a warm climate, while in the zone of northern and middle steppes it has limitations - the unsuccessful experience of introducing Italian durum wheat in the steppe zone of Russia is known.

Table 2.4

Assessing the feasibility of the food program J. Foley (2014) Five Steps, taking into account the potential of water resources

	Eco-social systems	"Steps" of the J. Foley program
	Voronezh region
	Stavropol region
	S.-V. China
	Central Asia (Turkmenistan)
	Rajasthan (India)
	S.-E. China

Rice. 2.83 Map of the use of nitrogen fertilizers in Eurasia (fragment of the world map).

Variably wet forests. The zone of variable wet (including monsoon) forests extends in the east and south of Eurasia. The vegetation here is represented by both coniferous and deciduous trees (cedar, pine, oak, walnut, gingko) and evergreens (palm trees, ficus, bamboo and magnolias), which grow mainly on red-yellow soils. The fauna is also characterized by significant species diversity: monkeys, tigers, leopards, as well as endemics - bamboo bear (panda), gibbon, etc.

Slide 11 from the presentation "Natural areas of Eurasia". The size of the archive with the presentation is 643 KB.

Geography 7th grade

summary of other presentations

“Natural zones of Eurasia” - Among the impenetrable thickets here you can find orangutans, leopards, and tapirs. Main animals: reindeer, arctic foxes, some species of birds. The latter predominates in the Asian taiga, in a cold, sharply continental climate. Arctic desert zone. Mixed and broad-leaved forests. The desert zone stretches across three geographical zones. The fauna here is represented by elephants, tigers, and rhinoceroses. Many reptiles and reptiles, as well as various insects. Along the mountain ranges of Siberia, tundra vegetation penetrates far to the south.

“Sights of Paris” - See Paris - and die! Arc de Triomphe in 1836 by Louis-Philippe. Place de la Star is officially called Place Charles de Gaulle. The Sorbonne was founded in 1253 by Robert de Sorbonne. Georges Pompidou - Beaubourg. The Pantheon is a monument that contains the tombs of great people of France. The Eiffel Tower is the symbol of Paris. The Louvre is one of the largest and richest museums of fine arts in the world. Goal: get to know the sights of Paris.

“Geographical location of the southern continents” - On plains composed of sedimentary rocks. Questions: To which oceans do the rivers of Africa and South America carry water? Why? Slide 7. Soil map. Igneous: ores of ferrous and non-ferrous metals, diamonds, noble and rare metals. General features of climate and inland waters. Slide 4. Minerals of the southern continents. Which climate zones have the largest network of rivers and many lakes?

“Geographic shell of the Earth” - The modern appearance of planet Earth. 1. Altitudinal zonality zonality... 6. The lithosphere is... Students of 7A class Matrosova A.E. A. state of the troposphere B. long-term weather regime C. state of the troposphere at the moment. A. on the plains B. in the mountains C. in the oceans 2. The geographical envelope is... Test work. Right answers.

“Water in the World Ocean” - Without water, a person cannot live for more than eight days. Thanks to water and in water, life arose on Earth. Next, deadly dehydration occurs. You can't grow crops without water. We begin to study the water shell of the Earth - the hydrosphere. Fundamental question: “Water! Group 2: Compare the area of ​​land and ocean. What is the temperature at different ocean levels?

“Savannahs” - Branched acacias rise like huge umbrellas among the tall grasses. Animal world. Savannah. Economic activities of people. The average temperature in July and January is +22C. Soils. Geographical position. Climatic conditions. Umbrella acacia. Savannas are located in the subequatorial belt.

Introduction

Eurasia is the largest continent on Earth, with an area of ​​53,893 thousand square kilometers, which is 36% of the land area. Population - more than 4.8 billion people.

The continent is located in the Northern Hemisphere between approximately 9° and 169° West longitude, with some of the islands of Eurasia located in the Southern Hemisphere. Most of continental Eurasia lies in the Eastern Hemisphere, although the extreme western and eastern ends of the continent are in the Western Hemisphere. Contains two parts of the world: Europe and Asia.

All climatic zones and natural zones are represented in Eurasia.

A natural zone is part of a geographical zone with homogeneous climatic conditions.

Natural areas take their name from their native vegetation and other geographic features. The zones naturally change from the equator to the poles and from the oceans deep into the continents; have similar temperature and moisture conditions that determine homogeneous soils, vegetation, fauna and other components of the natural environment. Natural zones are one of the stages of physical-geographical zoning.

The main natural zones of the subequatorial and equatorial belts of Eurasia considered in the course work are the zone of variable humid forests, including monsoon forests, the zone of savannas and woodlands, and the zone of equatorial forests.

A zone of variable humid, monsoon forests develops on the plains of Hindustan, Indochina and in the northern half of the Philippine Islands, a zone of savannas and woodlands - on the Deccan Plateau and the interior of the Indochina Peninsula, humid equatorial forests - throughout the Malay Archipelago, the southern half of the Philippine Islands, the southwest the islands of Ceylon and the Malacca Peninsula.

The course work provides a detailed description of these natural zones, reflecting the geographical location, climate, soils, flora and its ecological features, animal population and its environmental features. A current topic is also developed - environmental problems of the equatorial and subequatorial belts of Eurasia. First of all, these include the deforestation of moist equatorial forests and the desertification of savannas under the influence of grazing.

Zone of variable humid, including monsoon forests

Geographical location, natural conditions

In the subequatorial zone, due to seasonal precipitation and uneven distribution of precipitation over the territory, as well as contrasts in the annual course of temperatures, landscapes of subequatorial variable humid forests develop on the plains of Hindustan, Indochina and in the northern half of the Philippine Islands.

Variably humid forests occupy the most humid areas of the lower reaches of the Ganges-Brahmaputra, coastal areas of Indochina and the Philippine archipelago, and are especially well developed in Thailand, Burma, and the Malay Peninsula, where at least 1,500 millimeters of precipitation falls. On drier plains and plateaus, where precipitation does not exceed 1000-800 millimeters, seasonally wet monsoon forests grow, which once covered large areas of the Hindustan Peninsula and southern Indochina (Korat Plateau). With a decrease in precipitation to 800-600 millimeters and a reduction in the rainfall period from 200 to 150-100 days a year, forests are replaced by savannas, woodlands and shrubs.

The soils here are ferralitic, but predominantly red. As the amount of rain decreases, the concentration of humus in them increases. They are formed as a result of ferralite weathering (the process is accompanied by the decomposition of most of the primary minerals, with the exception of quartz, and the accumulation of secondary ones - kaolinite, goethite, gibbsite, etc.) and humus accumulation under the forest vegetation of the humid tropics. They are characterized by low silica content, high aluminum and iron content, low cation exchange and high anion absorption capacity, predominantly red and variegated yellow-red color of the soil profile, and a very acidic reaction. Humus contains mainly fulvic acids. They contain 8-10% humus.

The hydrothermal regime of seasonally wet tropical communities is characterized by constantly high temperatures and a sharp change in wet and dry seasons, which determines the specific features of the structure and dynamics of their fauna and animal population, which significantly distinguish them from communities of tropical rainforests. First of all, the presence of a dry season, lasting from two to five months, determines the seasonal rhythm of life processes in almost all animal species. This rhythm is expressed in the timing of the breeding season mainly to the wet season, in the complete or partial cessation of activity during drought, in the migratory movements of animals both within the biome in question and outside it during the unfavorable dry season. Falling into complete or partial suspended animation is characteristic of many terrestrial and soil invertebrates, amphibians, and migration is characteristic of some flight-capable insects (for example, locusts), birds, chiropterans and large ungulates.