The Yungas ( Aymara ''yunka'' warm or temperate

Andes The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range ...

or earth, Quechua ''yunka'' warm area on the slopes of the Andes) is a bioregion of a narrow band of forest along the eastern slope of the

Andes Mountains The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long and wide (widest between 18°S ...

from

Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...

and

Bolivia Bolivia, officially the Plurinational State of Bolivia, is a landlocked country located in central South America. The country features diverse geography, including vast Amazonian plains, tropical lowlands, mountains, the Gran Chaco Province, w ...

, and extends into Northwest Argentina at the slope of the Andes pre-cordillera. It is a transitional zone between the Andean highlands and the eastern forests. Like the surrounding areas, the Yungas belong to the

Neotropical realm The Neotropical realm is one of the eight biogeographic realms constituting Earth's land surface. Physically, it includes the tropics, tropical Ecoregion#Terrestrial, terrestrial ecoregions of the Americas and the entire South American temperat ...

; the climate is rainy, humid, and warm.

History

During the

Inca Empire The Inca Empire, officially known as the Realm of the Four Parts (, ), was the largest empire in pre-Columbian America. The administrative, political, and military center of the empire was in the city of Cusco. The History of the Incas, Inca ...

, the term ''yunga'' referred to both the western and eastern slopes of the Andes and their inhabitants. In the Spanish colonial era, it became primarily associated with the western foothills near the desert coast and the local Indians. Today, ''yunga'' can refer to the lower slopes on both sides of the Andes, though ''yungas'' mostly denotes the eastern foothills between the Andes and the Amazon basin, with both having mostly lost their ethnic associations.

Setting

The Yungas forests are extremely diverse, ranging from moist lowland forest to evergreen

montane forest Montane ecosystems are found on the slopes of mountains. The alpine climate in these regions strongly affects the ecosystem because temperatures lapse rate, fall as elevation increases, causing the ecosystem to stratify. This stratification is ...

and

cloud forest A cloud forest, also called a water forest, primas forest, or tropical montane cloud forest, is a generally tropical or subtropical, evergreen, Montane forest, montane, Tropical and subtropical moist broadleaf forests, moist forest characteri ...

s. The terrain, formed by

valley A valley is an elongated low area often running between hills or mountains and typically containing a river or stream running from one end to the other. Most valleys are formed by erosion of the land surface by rivers or streams over ...

s, fluvial mountain trails and

stream A stream is a continuous body of water, body of surface water Current (stream), flowing within the stream bed, bed and bank (geography), banks of a channel (geography), channel. Depending on its location or certain characteristics, a strea ...

s, is extremely rugged and varied, contributing to the ecological diversity and richness. A complex mosaic of habitats occur with changing latitude as well as elevation. There are high levels of

biodiversity Biodiversity is the variability of life, life on Earth. It can be measured on various levels. There is for example genetic variability, species diversity, ecosystem diversity and Phylogenetics, phylogenetic diversity. Diversity is not distribut ...

and species endemism throughout the Yungas regions. Many of the forests are evergreen, and the South Andean Yungas contains what may be the last evergreen forests resulting from

Quaternary The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS), as well as the current and most recent of the twelve periods of the ...

glaciations.

World Wildlife ecoregions

The

World Wide Fund for Nature The World Wide Fund for Nature (WWF) is a Swiss-based international non-governmental organization founded in 1961 that works in the field of wilderness preservation and the reduction of human impact on the environment. It was formerly named th ...

has delineated three yungas ecoregions along the eastern side of the Andes: * The northernmost is the

Peruvian Yungas The Peruvian Yungas comprise a tropical and subtropical moist broadleaf forest ecoregion in Peru. History During the Inca Empire, the term ''yunga'' referred to both the western and eastern slopes of the Andes and their inhabitants. In the Span ...

, located entirely within

and stretching nearly the whole length of the country. * The Bolivian Yungas lies to the south, entirely within

. The Cordillera Apolobamba marks the boundary between the Peruvian Yungas and Bolivian Yungas. * The Southern Andean Yungas begins in southern

and continues to the north of

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

. It is a humid forest region between the drier Gran Chaco region to the east and the dry, high altitude Puna region to the west. Yungas are transitional zones between the Andean highlands and the eastern forests. The yungas forests are extremely diverse, ranging from moist lowland forest to evergreen montane forest and cloud forests. The terrain is extremely rugged and varied, contributing to the ecological diversity and richness. A complex mosaic of habitats occur with changing latitude as well as elevation. There are high levels of biodiversity and species endemism throughout the yungas regions. Many of the forests are evergreen, and the South Andean Yungas contains what may be the last evergreen forests resulting from Quaternary glaciations.

Climate

The average temperature is 72 °F (22 °C). The climate is varied and ranges from a humid

tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

to the cold of the Andes over 10,000 ft (3,000 m).

Peruvian Yungas

In Peru there is a difference between Yunga and Yungas. Yunga is considered a natural region on both sides of the Peruvian Andes, the western side towards the coast is called Sea Yunga, and the eastern side into the jungle is called Fluvial Yunga, both reach a height of 2,300 m. Instead, Yungas is the ecoregion of rain forest and montane forest from 1.000 to 3.500 m, so it is limited to the eastern side of the Andes. This concept has a closer analogy with the Bolivian Yungas. This region is considered as the most endemic biodiversity of Peru. Forest loss in the Peruvian Yungas has sharply accelerated since the 2000s, rising seven-fold between 2005 and late 2012, according to satellite analysis by Terra-i.

Sea Yunga

Sea Yunga, or Maritime Yunga, is found between 500 and 2,300 m and it is situated between the eastern part of the coastal strip and the western part of the Highlands. This subregion has a

subtropical The subtropical zones or subtropics are geographical zone, geographical and Köppen climate classification, climate zones immediately to the Northern Hemisphere, north and Southern Hemisphere, south of the tropics. Geographically part of the Ge ...

desert A desert is a landscape where little precipitation occurs and, consequently, living conditions create unique biomes and ecosystems. The lack of vegetation exposes the unprotected surface of the ground to denudation. About one-third of the la ...

climate with little rainfall along the central and southern coast (drier as you go south). The average year round day temperature is (max 33 °C min 8 °C). A mist-fed ecosystem called Lomas is found at scattered locations among hills near the Pacific Ocean at elevations up to . The flora in the central Sea Yungas region is mainly composed by the

lucuma ''Lucuma'' is a genus of flowering plants in the family Sapotaceae. It includes 19 species native to the tropical and subtropical Americas, from Mexico and Florida to southern Brazil and northern Chile. The canistel ('' L. campechiana''), and the ...

and cherimoya trees, the casuarin, and others. Once you go north its climate becomes

in the vicinity of La Libertad, Lambayeque and Piura. Day time temperatures average between and depending on latitude (max 40 °C min 15 °C). As this area approaches the tropics, fauna differs from the rest of the coast, so that animals like the boas, larger

reptile Reptiles, as commonly defined, are a group of tetrapods with an ectothermic metabolism and Amniotic egg, amniotic development. Living traditional reptiles comprise four Order (biology), orders: Testudines, Crocodilia, Squamata, and Rhynchocepha ...

s and the famous white-winged guan (a bird species unique to this Peruvian ecoregion) occur here. Common trees in this area are the faique, the sapote, the zapayal, the '' barrigon'' and other thorny tropical savanna trees of the equatorial dry

forest A forest is an ecosystem characterized by a dense ecological community, community of trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, ...

s on the northern coast of Piura and Tumbes. The cooler Pacific side is more vaguely characterized. The dry and cool ''Yunga Coastal'' begins at 500 m above sea level. The Maritime Yunga begins dry, and it seems to follow ecotone on ecotone until reaching the Quechua region at the Pacific side.

Fluvial Yunga

Fluvial Yunga is between the altitudes of and and is found on the eastern part of Peru. This sub-region has a

climate with ample seasonal rains. The average temperature fluctuates between 20 °C and 25 °C depending on the altitude (max 35 °C, min 11 °C). Concept: The concept of the east side of the continental divide is straightforward: 1,000 m above sea level it is 4.9 °C cooler, and the subtropical cloud forest (Fluvial Yunga) follows the tropical rainforest (Anti). At 2,300 m, the climate transitions from subtropical climate to temperate climate ( Quechua). The

Tree line The tree line is the edge of a habitat at which trees are capable of growing and beyond which they are not. It is found at high elevations and high latitudes. Beyond the tree line, trees cannot tolerate the environmental conditions (usually low ...

ends at 3,500 m and has an annual mean temperature of 10 °C. The region between the

tree line The tree line is the edge of a habitat at which trees are capable of growing and beyond which they are not. It is found at high elevations and high latitudes. Beyond the tree line, trees cannot tolerate the environmental conditions (usually low ...

and 4,000 m is called Suni or Jalca. Suni is a dry and cold region with many glacial valleys. Despite the harsh weather, crops such as

quinoa Quinoa (''Chenopodium quinoa''; , from Quechuan languages, Quechua ' or ') is a flowering plant in the Amaranthaceae, amaranth family. It is a herbaceous annual plant grown as a crop primarily for its edible seeds; the seeds are high in prote ...

, maca, qañiwa, broad beans and ulluku are cultivated here.

Flora and fauna

The flora (subtropical

) of the Yunga region is mainly composed by the Peruvian pepper tree, the Furcraea, white cabuya (Furcraea andina), the pitahaya and the Peruvian torch cactus (''Echinopsis peruviana''). The coca leaf is established in this region as well as the uña de gato ("cat's claw", '' Uncaria tomentosa''). The most attractive sites of this warm refreshing region are its many

orchid Orchids are plants that belong to the family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant. Orchids are cosmopolitan plants that are found in almost every habitat on Eart ...

forests and beautiful valleys. The fauna in the Yunga region is characterized by the long-tailed mockingbird, or chaucato.

Overview

Andean Continental Divide Mountain Top: * Mountain passes – 4,100 m * Puna grassland ** Closed vegetation ** Sporadic vegetation * Andean-alpine desert *

Snow line The climatic snow line is the boundary between a snow-covered and snow-free surface. The actual snow line may adjust seasonally, and be either significantly higher in elevation, or lower. The permanent snow line is the level above which snow wil ...

– about 5,000 m * Janca – Rocks, Snow and Ice * Peak

Bolivian Yungas

Human use

In the early 20th century, the region was a major source for

rubber Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds. Types of polyisoprene ...

and

quinine Quinine is a medication used to treat malaria and babesiosis. This includes the treatment of malaria due to ''Plasmodium falciparum'' that is resistant to chloroquine when artesunate is not available. While sometimes used for nocturnal leg ...

. Now,

coffee Coffee is a beverage brewed from roasted, ground coffee beans. Darkly colored, bitter, and slightly acidic, coffee has a stimulating effect on humans, primarily due to its caffeine content, but decaffeinated coffee is also commercially a ...

citrus ''Citrus'' is a genus of flowering trees and shrubs in the family Rutaceae. Plants in the genus produce citrus fruits, including important crops such as oranges, mandarins, lemons, grapefruits, pomelos, and limes. ''Citrus'' is nativ ...

, and coca are important crops. People cultivate native plants like the canistel or eggfruit tree the lúcuma tree, the cherimoya or chirimoya, the guava or guayabo and the avocado or palta. The Afro Bolivian community is concentrated here. Its name derives from the one applied for the same mountain level by those who study the economic system of the prehispanic Andes. The Yungas also contains one of the most deadly roads in the world, called the "camino de la muerte," or Highway of Death. Due to the mountainous terrain an entrepreneurial coca harvester created a network of zip lines that permit rapid travel from peak to peak by farmers, referred to locally as flying men or bird men, along with their harvests using "zip line trollies."

Argentine Yungas

References

Other sources

* Endemic Bird Areas for th
Bolivian and Peruvian upper yungas
and th

BirdLife International, 2003. BirdLife's online World Bird Database. Version 2.0. Cambridge, UK. * * * {{Authority control Ecoregions of the Andes Subtropical rainforests Andean forests Montane ecology Tropical Andes Upper Amazon Ecoregions of South America Ecoregions of Argentina Ecoregions of Bolivia Ecoregions of Peru Geography of Bolivia Physiographic regions of Peru Regions of Argentina Natural history of Bolivia Natural history of Peru Natural regions of South America Regions of Bolivia Ecoregions Regions of Peru