Yungas

This article is about a geographic region. For the Yunga language, see Mochica language.

The Yungas is a stretch of forest along the eastern slope of the Andes Mountains from southeastern Peru through central Bolivia. It is a transitional zone between the Andean highlands and the eastern forests. Like the surrounding areas, it has characteristics of the Neotropic ecozone. It is rainy, humid, and warm (Yungas is Aymaran for “Warm Lands”).

Contents 1 Setting 1.1 World Wildlife Ecoregions 2 Flora and Fauna 2.1 Overview 2.2 Loma-Vegetation 2.3 Fluvial Yungas 3 Human Use 4 See also 5 References

Setting

The Yungas forests are extremely diverse, ranging from moist lowland forest to evergreen montane forest and cloud forests. The terrain, formed by valleys, fluvial mountain trails and streams, 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.

World Wildlife Ecoregions

The World Wide Fund for Nature has delineated three yungas ecoregions along the eastern side of the Andes. The northernmost is called the Peruvian Yungas (NT0153), located entirely within Peru and stretching nearly the whole length of the country. The Bolivian Yungas (NT0105) lies to the south, mostly in Bolivia but including part of southern Peru. The Inambari River marks the boundary between the Peruvian Yungas and Bolivian Yungas since the yungas north and south of the river have distinct ecological differences. The Southern Andean Yungas begins in southern Bolivia and continues south into Argentina. The Southern Andean Yungas (NT0165) is a humid forest region between the drier Gran Chaco region to the east and the dry, high altitude Puna region to the west.

All three yungas ecoregions 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. ^[1]

Flora and Fauna

This section is in need of attention from an expert on the subject. WikiProject Ecoregions may be able to help recruit one. (January 2009)

This article's factual accuracy is disputed. Please see the relevant discussion on the talk page. (June 2009)

The flora (subtropical cloud forest) of the Yungas 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 ("cats claw", Uncaria tomentosa). The most attractive sites of this warm refreshing region are its many orchid forests and beautiful valleys. The fauna in the Yungas region is characterized by the Long-tailed Mockingbird, or chaucato. ^{[2] [3]}

Overview

Andean Continental Divide

Westside	Eastside
Chala, dry coast	Lowland tropical rainforest or Selva baja
Loma-Vegetation	Highland tropical rainforest or Selva alta
-	Subtropical cloud forest or Fluvial Yungas
-	Quechua - Montane valleys
Westside has not a proper  Tree line[4]	Tree line - about 3,500 m
-	Suni, scrubs and agriculture

Mountain Top:

• Mountain passes - 4,100 m
• Puna grassland
  • Closed vegetation
  • Sporadic vegetation
• Andean-alpine desert
• Snow line - about 5,000 m
• Janca - Rocks, Snow and Ice
• Peak

Concept:

The concept of the east side of the continental divide is straightfoward. 1,000 m above sea level it is 4,9°C cooler, and the subtropical cloud forest (Fluvial Yungas) follows the tropical rainforest (Anti). The Tree line for Coniferae is at annual mean temperature of 10°C at 3,500 m. In the middle, 2,300 m is the transition to temperate climate (Quechua). Between Tree line and the annual mean temperature of 7.5°C^[4], crops are possible and the region is named Suni.

The cooler Pacific side is more vague. The dry and cool Yunga Costal begins at 500 m above sea level. The Maritime Yungas begins dry, and it seems to follow ecotone on ecotone until reaching the Puna region at the Pacific side.

Loma-Vegetation

Loma-Vegetation, is found between 450 metres (1,500 ft) and 600 metres (2,000 ft) and it is situated at the first westside slope near the coast in Peru^[4]. This subregion has a subtropical desert climate with little rainfall along the central and southern coast (drier as you go south). The average year round day temperature is 21 °C (70 °F) (max 33°C, min 8°C).

The flora in the region is mainly composed by the lucuma and chirimoya trees, the casuarin and others.

Once you go north its climate becomes subtropical in the vicinity of La Libertad, Lambayeque and Piura. Day time temperatures average between 21 °C (70 °F) and 25 °C (77 °F) 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 tree sloths, jaguars, boas, larger reptiles and the famous White-winged Guan or Pava Aliblanca (a unique bird species of this Peruvian ecoregion) occur here. Common trees in this area are the Faique, the Zapote, the Zapayal, the barrigon and other thorny tropical savanna trees of the equatorial dry forests on the northern coast of Piura and Tumbes. Páramo and the northern coast of the Piura region are not under the influence of the cold Humboldt Current. Páramo has a Tree line at the border, even on the westside of the continental divide.

Orientation:

• Lima, Peru; 30 m; annual mean temperature 19.2°C; annual mean precipitation 15 mm (cold Humboldt Current generates fog).
• Arequipa, Peru; 2,508 m; mean annual temperature 15.4°C; annual mean precipitation 99 mm. ^[5]
• Lomas de Lachay, Huaral Province in Lima, a unique mist-fed ecosystem.

Fluvial Yungas

Fluvial Yungas, that is between the 1,000 metres (3,300 ft) and 2,300 metres (7,500 ft), and is found on the eastern part of Peru. This sub-region has a subtropical 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).

Orientation:

• Yurimaguas, Peru; 184 m; annual mean temperature 26.9°C; annual mean precipitation 2,047 mm.
• Cuzco, Peru; 3,249 m; annual mean temperature 12.5°C; annual mean precipitation 736 mm. ^[5]
• La Raya pass, PeruRail scenic stop, 4,313 metres (14,150 ft), watershed between the amazon basin and the endorheic Altiplano basin (Lake Titicaca/ Lake Poopó), between Juliaca and Cuzco. The Juliaca junction links Puno, Arequipa and Cuzco,

14°28′59″S 70°59′20″W / 14.48306°S 70.98889°W / -14.48306; -70.98889 (Abra La Raya)

Human Use

In the early 20th century, the region was a major source for rubber and quinine. Now, Coffee, citrus, 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.^{[citation needed]}

The Afro Bolivian community is concentrated here.

The Yungas Cocalera Revolution is based in the region. Its name derives from the one applied for the same mountain level by those who study the economic system of the prehispanic Andes.

See also

• Geography of Bolivia
• Yungas Road, North road: 3,600 to 4,650 m (La Cumbre pass, Bolivia), then to 330 m in 61-69 km
• Peruvian Amazon
• Natural regions of Peru
• Climate zones by altitude
• Altitudinal zonation

References

• Endemic Bird Areas for the Bolivian and Peruvian upper yungas and the Bolivian and Peruvian lower yungas. BirdLife International, 2003. BirdLife's online World Bird Database. Version 2.0. Cambridge, UK.
• World Wildlife Fund profiles of the Peruvian Yungas, Bolivian Yungas, and South Andean Yungas.