The Marañón dry forests (NT0223) is an
ecoregion
An ecoregion (ecological region) is an ecological and geographic area that exists on multiple different levels, defined by type, quality, and quantity of environmental resources. Ecoregions cover relatively large areas of land or water, and c ...
in northern Peru.
It covers the lower valley of the
Marañón River and its tributaries along the eastern edge of the
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 ...
.
It has a dry climate due to rain shadow from mountains further east.
The habitat has long been modified by farming, ranching and logging and is now threatened by construction of hydroelectric and irrigation dams.
Location
The Marañón dry forests ecoregion in northwestern Peru has an area of .
It extends along the upper valley of the
Marañón River and its tributaries.
To the north the ecoregion adjoins the
Eastern Cordillera Real montane forests.
The northern part of the ecoregion extends from the
Tumbes–Piura dry forests in the west to the
Ucayali moist forests in the east.
The ecoregion extends to the southeast through 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 ...
and patches of the
Cordillera Central páramo
The Cordillera Central páramo (NT1004) is an ecoregion containing páramo (high moorland) vegetation above the treeline in the Andes mountain range of northern Peru and southern Ecuador. Due to its isolation there are high levels of endemism. De ...
.
Physical
The Marañón River rises on the Nevado de Yapura glacier, and runs northwest through northern Peru between the western and eastern ''cordilleras'' of the Andes.
It then turns northeast, breaks through the mountains and flows into the Amazon lowlands, where it meets the
Ucayali River
The Ucayali River (, ) is the main headstream of the Amazon River. It rises about north of Lake Titicaca, in the Arequipa region of Peru and becomes the Amazon at the confluence of the Marañón river, Marañón close to Nauta city. The city of ...
and forms the
Amazon River.
The ecoregion's most southern part is in the
Tayabamba District to the west of the
Rio Abiseo National Park.
It extends downstream along the river valley in a northwest direction to the region south of
Jaén where it is joined by the
Chamaya River and turns to the northeast.
It includes the valley of the
Chotano River, which flows northwest parallel to and west of the Marañó.
The Chotano joins the
Huancabamba River
The Huancabamba River ("Stony Plain" in the Quechuan languages, Quechua language) in the Pasco Region of Peru has its origin in the confluence of several small rivers near the town of Oxapampa: the Chontabamba, the Llamaquizú, and the Esperan ...
to form the Chamaya below
Pucará.
The Chamaya flows northeast to join the Marañó.
Beyond Jaén the ecoregion extends along the southeast bank of the Marañó, and includes the valleys of the
Utcubamba and
Chiriaco rivers, which enter the Marañó from the southeast, and the eastern part of
Cordillera de Colán National Sanctuary in the Chiriaco valley.
Climate
The ecoregion has a dry climate caused by the rain shadow from the mountains to the east.
The
Köppen climate classification
The Köppen climate classification divides Earth climates into five main climate groups, with each group being divided based on patterns of seasonal precipitation and temperature. The five main groups are ''A'' (tropical), ''B'' (arid), ''C'' (te ...
is "Cfb": warm temperate; fully humid; warm summer.
The valleys of the Utcubamba, Chamaya and Maranon rivers have similar climates.
At elevations above the mean annual temperature is and mean annual precipitation is .
At elevations below the mean annual temperature is and mean annual precipitation is .
At a sample location at coordinates yearly mean temperature averages , with an average low of and high of .
Mean monthly temperatures range from .
Average total rainfall is about .
Average monthly rainfall varies from in July to in March.
Ecology
The Marañón dry forests ecoregion is in the
neotropical
The Neotropical realm is one of the eight biogeographic realms constituting Earth's land surface. Physically, it includes the tropical terrestrial ecoregions of the Americas and the entire South American temperate zone.
Definition
In biogeogra ...
realm, in the
tropical and subtropical dry broadleaf forests
The tropical and subtropical dry broadleaf forest is a habitat (ecology), habitat type defined by the World Wide Fund for Nature and is located at tropical and subtropical latitudes. Though these forests occur in climates that are warm year-roun ...
biome.
The ecoregion is part of the Tumbesian-Andean Valleys Dry Forests global ecoregion, which holds six terrestrial ecoregions:
Tumbes–Piura dry forests,
Ecuadorian dry forests
The Ecuadorian dry forests (NT0214) is an ecoregion near the Pacific coast of the Ecuador.
The habitat has been occupied by people for centuries and has been severely damaged by deforestation, overgrazing and hillside erosion due to unsustainable ...
,
Patía Valley dry forests
The Patía Valley dry forests (NT0225) is an ecoregion in southwestern Colombia. It covers a dry valley surrounded by mountains.
The original habitat has mostly been destroyed by human activity, although a few pockets remain.
Location
The Patía V ...
,
Magdalena Valley dry forests
The Magdalena Valley dry forests (NT0221) is an ecoregion in Colombia along the upper Magdalena River, a large river that runs from south to north between the two main ''cordilleras'' of the Andes. There are many endemic species, but much of the o ...
,
Cauca Valley dry forests
The Cauca Valley dry forests is a tropical dry broadleaf forest ecoregion in Colombia.
Location
The Cauca Valley dry forests occupies an area of , extending in a long, narrow strip along the Cauca River. The Cauca Valley is nestled between th ...
and Marañón dry forests.
The fauna and flora of the global ecoregion have high levels of endemism.
Flora
The ecoregion holds seasonally dry tropical deciduous forest and arid or riparian scrub.
Botanically it is the richest of the inter-Andean valleys, with 184 woody plant species.
Characteristic species include ''
Acacia macracantha
''Vachellia macracantha'' is a species of tree in the family Fabaceae. Its native range spans from southern Florida to South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, ...
'', ''
Athyana weinntanniifolia'', ''
Ceiba insignis'', ''
Cordia iguaguana'', ''
Cyathostegia mathewsii'', ''
Eriotheca discolor'', ''
Eriotheca peruviana'', ''
Geoffroea spinosa'', ''
Hura crepitans'', ''
Krameria lappacea
''Krameria lappacea'', commonly known as para rhatany and Peruvian rhatany, is a plant species in the genus ''Krameria'', native to Ecuador, Peru, Bolivia, northern Chile and northwest Argentina. It is a slow-growing shrub that grows in semi-arid ...
'', ''
Llagunoa nitida'', ''
Parkinsonia praecox'', ''
Praecereus euchlorus'' and ''
Rauhocereus riosaniensis''.
69 species are endemic to Peru and many are found only in small, isolated areas.
These include ''
Browningia riosaniensis'', ''
Praecereus euchlorus'', ''
Coursetia cajamarcana'' and ''
Coursetia maraniona''.
Recently described species include ''
Parkinsonia peruviana'', ''
Ruprechtia aperta'' and ''
Ruprechtia albida'', as well as the new genus ''
Maraniona''.
Fauna
Endangered amphibians include the painted frog (''
Atelopus pachydermus'').
There is a high level of endemism among birds, with 22 species of restricted-range, of which 11 are endemic.
Endangered birds include the
yellow-bellied seedeater (''Sporophila nigricollis'') and
Marañón spinetail (''Synallaxis maranonica'').
Status
The area has long been affected by agriculture, cattle ranching and logging.
Plans to build a series of 20 hydroelectric and/or irrigation dams on the Marañón River were announced by President
Alan García
Alan Gabriel Ludwig García Pérez (; 23 May 1949 – 17 April 2019) was a Peruvian politician who served as President of Peru for two non-consecutive terms from 1985 to 1990 and from 2006 to 2011. He was the second leader of the American Popula ...
in April 2011.
18 of the dams would be in environmentally sensitive areas, include the dry forests, and would displace indigenous people and other farmers and fishermen along the river.
Notes
Sources
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{{DEFAULTSORT:Marañón dry forests
Neotropical dry broadleaf forests
Ecoregions of Peru