Amazonas High Andes
Paulo Petry, The Nature Conservancy
Major Habitat Type
Drainages flowing into
Amazon River, Atlantic Ocean
Main rivers to other water bodies
Notable rivers that originate in the ecoregion include the Caguán, Caquetá, Putumayo, Aguarico, Napo, Cuaray, Tigre, Pastaza, Marañón, Hulluaga, Perené, Mantaro, Pampas, Apurímac, Ucayali, Urubamba, Madre de Dios, Beni, and Grande.
The ecoregion includes drainages along the eastern slopes of the Andes above 800 m that drain into the Amazon Basin. It extends from the Río Caguán in Columbia south to the Río Grande, a tributary of the Mamoré in Bolivia.
The topography of the Andes is complex and dramatic, punctuated by steep ranges that demarcate the western boundary of the Amazon Basin. Compared to the Guiana and Brazilian shields, the Andes are geologically young and tectonically active. The ecoregion includes much of the central and eastern slopes that extend from roughly the 800 m elevation contour to over 5000 m asl. Some peaks, like Nevado Ausangate in the Cordillera Vilcanota near Cusco, Peru, exceed 6000 m. Soils are composed of inceptisols, ultisols, mollisols, and exposed rock (at high elevations >4000 m asl).
Most Andean streams are fast-flowing and are marked by rapids, waterfalls, gorges, and rocky beds. They are clear during the dry months and become turbid during heavy precipitation. There are also a number of alpine lakes filled with snowmelt. Glacial waters from Nevado Mismi flow into the Río Apurímac and are considered the headwaters of the Amazon. The four major Andean tributaries (with headwaters above 500 m) that intersect with the Amazon main stem are the Solimões, Iça (Putumayo), Japurá (Caquetá), and Madeira. Together their mean annual flow is 90,000 m3/s, which is roughly half of the Amazon’s mean annual discharge. Even though the Andes supplies less than 25% of the water volume to the Amazon, it supplies a disproportionate amount (more than 90%) of suspended sediments. Many high-altitude rivers have a pH greater than 7.0, with some as high as 8.75. They also tend to have high conductivity levels and high dissolved oxygen levels.
There are a number of Ramsar sites in the ecoregion, including Laguna de la Cocha; Ñucanchi Turupamba wetland complex; Complejo Llanganti, a complex of glacial lagoons; Lagunas Las Arreviatadas, a wetland complex with glacial lagoons; Reserva Nacional de Junín, a high-altitude freshwater lake; and Humedal Lucre – Huacarpay, a high-altitude wetland.
The Andes are considered to be one of the most diverse areas on earth. Terrestrial habitats in the ecoregion are roughly divided into submontane forest (700-2000 m), montane forest (2000-2500 m), cloud forest (2500-3500), and puna (3500-5000 m). The montane and cloud forests are very diverse and form a transition between the Amazonian lowland forests and puna.
Description of endemic fishes
There are 17 recorded endemic fish in five families. Of these, more than 70% occur in three genera: Orestias, Trichomycterus, and Astroblepus. The high Andean lakes and streams are home to a handful of endemic Orestine fish (O. gymnotus, O. jussiei, O. mundus, O. polonorum, and O. empyraeus) and a few endemic pencil (Trichomycterus) and climbing (Astroblepus) catfishes.
Other noteworthy fishes
Astroblepid catfishes (comprising a single genus) have specially adapted suckermouths and pelvic fins that enable them to climb up the faces of waterfalls.
Justification for delineation
This ecoregion falls within the North Andean ichthyographic province defined by Ringuelet (1975), and within the Andean ichthyographic region defined by Gery (1969). Because astroblepid catfishes are distinct components of high-elevation freshwaters along the Andes forefront, that family’s distribution was critical to informing the delineation of the high Andean ecoregions. It is also distinguished by rivers that drain into the Amazon Basin.
Level of taxonomic exploration
- AmphibiaWeb (2010) \Information on amphibian biology and conservation. [web application].\ (Berkeley, California)
- Gery, J. (1969). "The fresh-water fishes of South America" E. J. Fitkau (Ed.) Biogeography and Ecology in South America ( pp. 828-848 ) The Hague: Dr. W. Junk.
- Goulding, M., Barthem, R. and Ferreira, E. (2003). "The Smithsonian Atlas of the Amazon" Washington DC: Smithsonian Books.
- Goulding, M., Carlos Cañas, Ronaldo Barthem, et al. (2003). "Amazon Headwaters: Rivers, Wildlife and Conservation in Southeastern Peru" Lima, Peru: Graphica Biblos S. A..
- Hijmans, R. J., S. Cameron and Parra., J. (2004) \WorldClim, Version 1.4 (release 3). A square kilometer resolution database of global terrestrial surface climate\ "<"[http://www.worldclim.org]">" (16 July 2009)
- IUCN (2009) \IUCN Red List of Threatened Species. Version 2009.1\ "<"http://www.iucnredlist.org">" (08 July 2009)
- Lowe-McConnell, R. H. (1987). "Ecological studies in tropical fish communities" Cambridge, UK: Cambridge University Press.
- McClain, M. E. and Naiman, R. J. (2008). "Andean Influences on the Biogeochemistry and Ecology of the Amazon River" BioScience 58 (325-338)
- Ringuelet, R. A. (1975). "Zoogeografía y ecología de los peces de aguas continentales de la Argentina y consideraciones sobre las áreas ictiológicas de América del Sur" Ecosur 2 (1) pp. 1-122.
- Wetlands International (2005) \Ramsar Sites Database: A directory of wetlands of international importance\ "<"http://www.wetlands.org">" (February 8, 2010)