Peru is known as one of the world's 10 megadiverse countries and its biodiversity can be organized into four main biomes. Geographically, Peru is traditionally described in terms of three broad longitudinal regions: the Costa, the Sierra and Amazonia.
The Natural and Geographic Landscape of Peru
Peru is known as one of the world's ten megadiverse countries. The country has 84 of the 103 existing ecosystems and 28 of the 32 climates on Earth.
Peru's biodiversity can be organized into four main biomes:
Tropical and Subtropical Dry Broadleaf Forest
Map of Peru and its four biomes
Peru is traditionally described in terms of three broad longitudinal regions. Each of these regions comprises a different topography and sharply contrasting environment, thus forming the major terrestrial regions of the country.
the arid Costa (La Costa), or coastal region, in the west
the rugged Sierra (La Sierra), or Peruvian Andes, in the middle
the wet and forested Amazonia (La Selva), or jungle region, in the east
Three broad climatic regions can be readily distinguished paralleling the three main geographic regions: coastal desert, mountain highland and tropical forest.
Map of Peru, showing its three geographical regions and 25 departments
Coastal Plain (La Costa)
The coastal region of Peru is a bleak, often rocky desert that runs the entire length of the country, from Ecuador in the north to Chile in the south. The landscape is punctuated by a multitude of rivers and streams that descend through steep, arid mountains in the east and empty into the Pacific Ocean in the west.
The coastal plain can be readily divided into three parts: north, central and south. Generally speaking, the amount of level coastal land diminishes from north to south.
In the northern region, the plain is typically some 30 - 50 km (20 - 30 mi) wide, with a maximum width of more than 140 km (90 mi) in the Sechura Desert.
The central coastal region is narrower than the northern region and is characterized by areas of rough hills that extend from the Andes to the shores of the ocean.
From Nazca southward to the Chilean border the coast is mostly lined by low mountains with narrow valleys near the ocean.
Evidence of plant life is relatively rare in the barren desert of coastal Peru. Where coastal fog is heavy, Lomas (a mix of grasses and other herbaceous species) are common. In the north coast region, some parts of the desert are covered by epiphytes or by stands of sapote or algarroba (mesquite).
The most important feature of the coast is the enormous amount of bird, marine mammal and fish life that abounds in the coastal waters. These include anchovies, Corvina (sea bass), tuna, swordfish and marlin. Sea lions thrive in isolated parts of the coast.
Birdlife is heavy on islands off the coast. Among the most important bird species are pelicans, cormorants, gannets and various gulls. Humboldt penguins, an endangered species, are found as far north as the Ballestas Islands near the Paracas Peninsula.
Coastal Desert Climate
The west coast of Peru, from the Peruvian-Ecuadoran border south to northern Chile, has one of the Earth’s driest climates. The Andes Mountains block rain-bearing winds from the Amazon Basin. thus air masses moving toward the coast produce little rainfall and northward-flowing cold water off the coast (the Humboldt Current) contributes little moisture to surface air masses.
Temperatures in this coastal desert are not hot, however. Average temperatures of the Costa range from 19 °C (66 °F ) in winter to 22 °C (72 °F ) in summer. Despite its dryness, some parts of the coastal region receive sufficient moisture from winter fogs (locally known as garúa) to support some vegetation.
Andean Highlands (La Sierra or Los Montañas)
The Sierra highlands natural region, containing the Peruvian Andes, is the commanding feature of Peru. Hundreds of permanently glaciated and snowcapped peaks tower over the valleys. It includes the Altiplano plateau as well as the highest peak of the country, the 6,768 m (22,205 ft) Huascarán.
The Sierra contains the headwaters of the streams that flow to both the Pacific Ocean and the Amazon Basin. In the south, several rivers cross the altiplano in Peru to empty into Lake Titicaca, the world's highest navigable body of water.
The steep, desiccated Pacific flank of the Andes supports only a sparse population in villages located at infrequent springs and seepages. In contrast, tropical forests blanket the eastern side of the Andes. Between these extremes lie the most populous highland ecological zones: the intermontane valleys (kichwa) and the higher uplands and grassy puna or Altiplano plateaus.
Slopes are relatively gentle in northern Peru. The Andes Mountains in central Peru are higher and more rugged. The ranges of the central zone form particularly difficult barriers to movement. In southern Peru the character of the Andes changes to that of a high plateau region; this is the Altiplano, with vast tablelands.
Two plant communities characterize the Peruvian highlands: puna grasslands at higher elevations and a mixture of native and introduced species at the lower elevations. The Puna has an abundance of forage grasses and is home to the llama, alpaca, vicuña and guanaco, which are native to the region. Several species of eucalyptus have replaced native tree species.
The Sierra exhibits a wide range of climates that vary according to such factors as latitude, elevation, local winds and rain shadow effects. In general, temperatures decrease as elevation increases and rainfall decreases from north to south and from east to west. Snow falls in the Sierra at higher elevations, and many peaks have permanent snow.
Amazonia (La Selva)
The western slopes of the Peruvian Andes merge with the forested tropical lowlands of the Amazon Basin and form the region known as Amazonia or La Selva (the jungle), which occupies more than 60% of the area of Peru. An area of dense cloud forests is found in the zone immediately adjacent to the Andes.
The physiography of the region is characterized by rolling hills and level plains that extend eastward to the borders of Colombia, Brazil and Bolivia. Elevations are uniformly low, ranging from about 1,000 m (3,300 ft) at the eastern edge of the Andes to about 80 m (206 ft) above sea level along the Amazon River at the Peru–Brazil border.
Amazonia is characterized by great rivers. The Amazon River has headwaters that rise in several places in the Peruvian Andes; one of the main branches, the Ucayali, originates in southern Peru. These tributaries, which include the Marañón, Huallaga and Ucayali, flow northward in long deep valleys before turning east to join the Amazon.
The eastern slopes of the Andes and the Amazon plains are covered by a heavy growth of the tropical forest. The forests have a broad assortment of hardwood and softwood species that produce a variety of forest products.
In these forests and waters live thousands of plant, insect, and animal species. Interesting mammals of this region include the jaguar, capybara, tapir and several species of monkey. Of special note is the wide and colorful variety of bird and fish life. Reptiles and insects abound.
Tropical Forest Climate
Hot humid conditions characterize the Amazonia climate of eastern Peru. Rainfall throughout the region is high, with precipitation common throughout the year. There is very little seasonal temperature variation.
Vegetation map of Peru