ECOSYSTEMS OF PERU: AMAZON, ANDES, COASTS, DESERTS, RIVERS - ENVIRONMENT - 2024

The ecosystems of Peru are quite diverse mainly due to the geographical location and physiography of this country. Peru is located in the tropical zone, between the equatorial line and the Tropic of Capricorn in South America and is considered one of the 12 countries with the most ecosystems in the world.

This country has a territory of very varied relief, crossed from south to north by the Andes mountain range, defining two areas. The first is a strip along the Pacific coast on the western Andean slope. For its part, the second corresponds to the Amazon basin on the eastern slope, which drains into the Atlantic Ocean.

Satellite view of Peru. Source:

The Peruvian Andes establish an altitudinal variability that ranges from sea level to 6,757 meters above sea level. in the snowy El Huascarán massif. On the Andean slope of the Pacific Ocean, towards the south coast, it is influenced by the cold-water Humboldt current.

In addition, to the north of Peru there are tropical waters with mangrove development due to the Equatorial Countercurrent. On the other hand, oceanic influence affects the types of ecosystems that develop on this slope, which are generally arid and semi-arid.

For its part, the eastern slope belongs to the Amazon basin that drains into the Atlantic Ocean. This is much more humid and has a variety of Andean and Amazon ecosystems, also being the endorheic basin (closed basin, without fluvial outlet) of Lake Titicaca.

Peru has numerous rivers, lakes and lagoons, which determine a great variety of freshwater ecosystems. Of the rivers, those of the Amazon river basin stand out, with the Mantaro river being part of its source.

The Amazon River basin covers about 75% of Peru's territory and Titicaca stands out among the country's lakes. This is considered one of the largest in America and the highest navigable lake in the world.

For all this, various terrestrial and aquatic ecosystems have developed in the Peruvian territory. According to the studies of the Peruvian researcher Antonio Brack Egg, in Peru up to 11 ecoregions can be identified.

The ecoregions include marine and terrestrial areas and different types of ecosystems develop in them. On the other hand, the National Ecosystem Map of Peru establishes 5 large regions with 36 ecosystems.

Of these 11 are from tropical rainforest, 3 from yunga, 11 from the High Andes, 9 coastal and 2 aquatic. In addition, we must add the marine ecosystems that are not developed in this proposal.

Simplifying the complex diversity of ecosystems that exist in Peru, below are 7 large groups of ecosystems. This according, mainly, to their geographical, climatic, flora and fauna affinities.

Amazon ecosystems

- Diversity of ecosystems

The Peruvian Amazon region includes diverse ecosystems, such as savannas, swamps, low floodplain forests, high forests and mountain forests. The ecosystem that occupies the highest percentage of the Peruvian territory (25%) are the low hill forests.

Low hills jungle

They are Amazon rainforests of 3 to 4 layers with trees of up to 25-30 m and emerging individuals of up to 50 m. It has a dense undergrowth and they develop in non-floodplain of hills 20-80 m high.

- relief

This region consists mainly of undulating plains, hills and terraces ranging from the Andean foothills to the continental interior.

Low flood zones are found here where both swamps and jungles and non-flooded zones with jungles and humid savannas develop. The Amazon rainforest areas are part of the most diverse ecosystems on the planet, with about 300 species of trees per hectare.

- Weather

It is a climate without great fluctuations throughout the year, with an average annual temperature of around 25 ºC and high rainfall (1,300-3,000 mm). Although towards the south in the dry season (June-July) the temperatures decrease considerably, calling these periods “cold”.

- Flora

The diversity of plants in the Amazon is very high given the complexity of its ecosystems. It is estimated that there are around 16,000 species of trees in this region.

Amazon rainforest of Peru. Source: Martin St-Amant (S23678)

On the other hand, there is a great diversity of herbaceous and shrubby plants, both terrestrial and climbing, epiphytic and aquatic. Among the plants that inhabit the Amazon River, the water lily (Victoria amazonica) stands out.

- Fauna

The Amazon is one of the most diverse regions on the planet also in fauna. Here you will find animals such as the jaguar (Panthera onca), the anaconda (Eunectes murinus), the tapir (Tapirus terrestris), among many others.

Yunga ecosystems

In a geographical sense the yunga is part of the Andes mountain range, however due to its peculiarities it is considered a particular area. In Peru, an area occupied by Andean rain forests or cloudy rainforests is called yunga.

Yungas in Peru. Source: Erfil

The maritime yunga on the western slope (western yunga) and the river yunga on the eastern slope (eastern yunga) are identified.

- Western or maritime Yunga

This corresponds to the region located on the western slope of the Andes between 500 and 2,300 meters above sea level, with an arid subtropical climate. Here a mainly xerophilous vegetation develops in the lower parts and as you go up you will find a tall forest.

- Eastern or fluvial Yunga

This ecosystem is located between 600 and 3,200-3,600 meters above sea level, presenting a humid subtropical climate, with rains that can exceed 3,000 mm per year.

In the south and center of the country, the yunga reaches its altitude limit bordering on the puna and the jalca. While in the north of Peru this jungle at its highest limit adjoins the páramo.

Among the many species of trees present in these forests is cinchona (Cinchona pubescens). This species is the emblematic tree of Peru, especially for its medicinal properties to combat malaria and malaria.

Structure

The jungle varies in structure as you ascend and up to 2,500 meters above sea level. the trees reach up to 30 m in height. Above that altitude, the canopy decreases to about 15 m in height on average.

Climbing and epiphytism (orchids, bromeliads) as well as various species of ferns and palm trees are abundant in this type of jungle.

Phytogeographic relationship

The fluvial yunga corresponds to the cloud forest of the tropical Andes. These stretch from Venezuela and Colombia to Ecuador and even a small portion of northern Peru.

Equatorial dry forest ecosystem

There is no geographic continuity between the eastern Peruvian yunga and the Andean cloud forest of the tropical Andes. This is due to the fact that the yunga is interrupted by the presence of the equatorial dry forest or Tumbesian Region.

- Location

This forest extends from the Gulf of Guayaquil to the La Libertad region. It penetrates inland into the Marañón valley, reaching 2,800 meters above sea level.

- Characteristics

It is a relatively low forest with some outstanding species such as the ceiba (Ceiba pentandra) and a predominance of cacti, legumes, malvaceae and grasses.

They present a high proportion of deciduous plants in the dry season, a hot and dry period that can last up to 9 months.

High Andean ecosystems

This group includes the Andean high mountain ecosystems, that is, the steppe mountains, the puna and the jalca or páramo. Seasonally dry forests develop in the intramontane valleys.

- Steppe mountains

It includes the Pacific slope in an altitude range between 1,000 and 3,800 meters above sea level, from La Libertad to the north of Chile. It includes diverse ecosystems, such as semi-deserts, shrubs, mountain steppes and low dry forest.

There are species of grasses, cacti, bromeliads, among many other families of plants. Among the animals there is a great diversity of American camelids such as the llama (Lama glama), the guanaco (Lama guanicoe), the alpaca (Vicugna pacos) and the vicuña (Vicugna vicugna).

- The puna

This ecosystem corresponds to the Andean highlands, located above 3,800 meters above sea level, with high solar radiation and a cold and dry climate. It is the Andean highlands and is dominated by grasslands with a predominance of ichu grass (Stipa ichu).

Humid puna in the Conococha Lagoon (Peru). Source:

Among the fauna are the vicuña, the vizcacha (Lagidium viscacia), the Andean fox (Lycalopex culpaeus andinus) and the taruca (Hippocamelus antisensis).

- The jalca or páramo

This ecosystem corresponds to the high mountain environment above the tree line in the tropical Andes. In Peru it is found in the extreme north on the border with Ecuador, in the regions of Piura and Cajamarca. They are distributed at altitudes around 3,500 meters above sea level.

Some researchers call them páramo, while others state that they are not strictly páramos and call them jalcas. According to this criterion, the jalca is drier than the páramo, but more humid than the puna.

- Seasonally dry inter-Andean forests

They develop in the Andean intramontane valleys between 500 and 2,500 meters above sea level and deciduous species predominate in them. The arboreal layer reaches about 7-8 m in height and arborescent cacti are abundant.

Coastal ecosystems

- Pacific coastal desert

It forms an extensive strip along the entire coast from the Chilean border to the Piura region in the north. On the border with Chile is the continuation of the Atacama desert, one of the driest in the world.

Other emblematic deserts of Peru that are part of this extensive region are Nazca and Sechura. These desert ecosystems are extremely dry and have low biological diversity.

In the Nazca desert are the famous Nazca lines, some geoglyphs that cover 1,000 km². The figures they form can only be appreciated from the air.

- Mangrove

It is a tropical ecosystem of trees adapted to high salinity conditions that develops in coastal marine environments. In Peru it is located on the north coast where the influence of the Equatorial Countercurrent brings warm waters.

Further south they cannot develop due to the influence of the Humboldt Current or Peruvian Current.

Flora

There are the red mangrove species Rhizophora mangle and Rhizophora harrisoni, as well as the jelí or white mangrove (Laguncularia racemosa). Also the black or salty mangrove (Avicennia germinans) and the pineapple mangrove (Conocarpus erecta).

- Seasonally dry forest

It is a deciduous forest formation with a semi-arid climate with a canopy between 8 and 12 m high. It presents an undergrowth of herbs, shrubs and cacti on hills and low mountains.

- Pacific tropical forest

Although this forest forms a biome that extends from Peru to Costa Rica, in the country it only covers a very small area. This region is located in the extreme northwest in the department of Tumbes.

These are dense and tall evergreen forests with trees up to 50 m tall in a hot and humid climate. Various species of Ficus (Moraceae), Cedrela (Meliaceae), Tabebuia (Bignoniaceae) inhabit them.

Other common plants in these ecosystems are legumes as well as a great diversity of palms, orchids and bromeliads.

These forests are the only areas of the Peruvian coast where the howler monkey (Alouatta palliata) and the white monkey (Cebus albifrons) live. There are also the arboreal anteater (Tamandua mexicana) and the jaguar (Panthera onca).

Freshwater ecosystems

- Rivers

In Peru there are about 144 rivers, 60 of them tributaries of the Amazon basin, 64 of the Pacific basin and 20 of the Lake Titicaca basin. The Amazon river basin originates in this country and covers 75% of its territory.

- Lakes and lagoons

In Peru there are more than 12,000 lakes and lagoons, 61% of them on the Atlantic slope (Amazon basin). Then 32% is on the Pacific slope and the remaining 7% in the Lake Titicaca basin.

Lake Titicaca

Lake Titicaca near Puno (Peru). Source: Alexander Fiebrandt

The most important lake is Titicaca, one of the largest in South America and the highest navigable lake in the world. An endemic species to this region is the giant frog (Telmatobius culeus), 14 cm long and 150 g in weight.

Marine ecosystems

The Peruvian marine waters can be divided into two defined zones that are the cold sea and the tropical sea. The cold sea is determined by the effect of the Peruvian Current or Humboldt Current.

For its part, the tropical sea is influenced by the warm waters of the Equatorial Countercurrent.

- The cold sea

The cold sea goes from central Chile to Piura in Peru, with temperatures between 13-17 ºC. They are waters with abundant nutrients and a great diversity of aquatic life, including about 600 species of fish and species of dolphins, whales and sea lions.

Outcrop of waters

This richness of nutrients is due to the phenomenon of "upwelling" due to the cold Humboldt current moving nutrients from the seabed to the surface. With more content of nitrates, phosphates and silicates, plankton that is the base of the marine food chain proliferates.

- The tropical sea

The tropical waters of the American Pacific begin in Piura (Peru) and extend to California in the United States. The Peruvian coasts of this region are warm all year round, with temperatures above 19ºC.

On the other hand, they have low salinity due to the high rainfall that provides fresh water.

Nutrient poverty

Unlike the cold sea, it is poor in nutrients and has less dissolved oxygen given the higher temperatures. Species such as black merlin (Istiompax indica) and yellowfin tuna (Thunnus albacares) are found here. And in the mangrove areas you can find the American or Tumbes crocodile (Crocodylus acutus).

References

1. Calow, P. (Ed.) (1998). The encyclopedia of ecology and environmental management.
2. Ministry of Agriculture and Irrigation (2016). Descriptive memory of the ecozone map. National Forest and Wildlife Inventory (INFFS) -Peru.
3. Ministry of the Environment (2016). National map of ecosystems of Peru. Descriptive memory.
4. Purves, WK, Sadava, D., Orians, GH and Heller, HC (2001). Life. The science of biology.
5. Sánchez-Vega et al. (2005). La Jalca, the cold ecosystem of the Peruvian northwest - Biological and Ecological Fundamentals.
6. Tovar, C., Seijmonsbergen, AC, and Duivenvoorden, JF (2013). Monitoring land use and land cover change in mountain regions: An example in the Jalca grasslands of the Peruvian Andes. Landscape and Urban Planning.
7. Peruvian University Cayetano Heredia. Center for Pre-University Studies. The 11 Ecoregions of Peru. (Posted on August 13, 2012). upch.edu.pe