Location and General Description
The Central Andean Dry Puna is located in the southern part of the Andean Cordillera Occidental in the countries of Argentina, Bolivia and Chile. The area encompasses snow-capped peaks, volcanoes, salt flats, lagoons and high plateaus. The ecoregion includes the departments of La Paz, Oruro and Potosi in Bolivia; the provinces of Jujuy, Salta, Catamarca, and La Rioja in Argentina; and the provinces of Tarapaca, Antofagasta, and Atacama in Chile.
The Andes were formed by large introsions of igneous rock and volcanic activity. The formation was assumed its present form in the Tertiary period approximately 50 million years ago. This ecoregion encompasses many volcanic mountains and the high plateau to the east called the Altiplano. It is in this area that there existed an extensive inland sea, of which all that remains are the salt flats or salares, including the salares of Coipasa, Uyuni, Chalviri, Atacama, and Arizaro. (Kricher 1997).
The region lies at an elevation of 3,500-5,000 m above sea level. The dry puna is oligothermic. The northern part of the ecoregion has a temperature ranging from 8 to 11 oC; temperatures in the southern area are lower. The mid-southern sections of the ecoregion are drier than the north, with an annual precipitation that varies from 51 mm to 406 mm (Ribera Arismedi 1992).
At high elevations over 4,000 m above sea level, the vegetation in cushion bogs or bofedales includes floating submerged cushion plants. Large cushions are formed by Distichia muscoides, Oxychloe andina and Plantago rigida. Other genera include Gentiana, Hypsela, Isoetes, Lilaeopsis, Ourisia, and Scirpus (Morales 1990; Young et al. 1997). In well-drained areas some of the cushion plants include Azorella compacta and Werneria aretioides.
From east to west the vegetation changes in the ecoregion, from shrubland steppe with xerophilous shrubs such as Adesmia, Baccharis, Fabiana, and Senecio to grassy steppe with grasses of the genera Calamogrostis, Festuca, and Stipa (UNESCO 1981). Some of the common shrubs are Baccharis incarum, B. boliviensis, Parastrephila lepidophylla and Fabiana densa. In some area these shrubs reach heights of 2.5 m (Ribera Arismedi 1992).
Polylepis (Rosaceae) is only found in the South American Andes. Most of the species in this genus are exposed to harsh climatic conditions. Unique forests of Polylepis tomentella and P. tarapacana are found around the Sajama Volcano at 5,000 m above sea level in Bolivia (Ribera Arismedi 1992). The departments of Oruro and Potosi in Bolivia have desert-like habitats with sand. Some of the flora found in these desert-like areas include Lampaya sp. Parastrephila lepidophylla, and grasses such as Festuca orthophylla (Ribera Arismedi 1992). In some areas of Argentina, the Andean degraded caespitose (growing in dense tufts) herbaceous vegetation with open stands of dwarf shrubs includes Acantholippia hastulata, Adesmia horridiuscula, Baccharis incanum, Ephedra breana, Fabiana densa, Junellia seriphioides, Psila boliviensis, Senicio viridis, and Tetraglochin cristatum (UNESCO 1981).
Some of the vegetation that has adapted to high concentrations of salt in the soil constitutes halophyte communities, which are found especially in areas close to the salt flats. Some of these species include Anthobryum sp., Atriplex atacamensis, Distichlis humilis, Muhlenbergia fastigiata, Parastrephia lucida, Salicornia pulvinata, Senecio pampae, Suaeda foliosa, and Tessaria absintoides, Triglochin maritima (Ribera Arismedi 1992) (UNESCO 1981). Some of the "islands" that are found in the Uyuni salt flats include cacti of the genus Oreocereus.
Flora restricted to this and other ecoregions include the genera Barneoudia, Hexaptera, Nototriche, Pycnophyllum and Werneria (Davis et al. 1997).
Mammals in the region include vicuña (Vicugna vicugna), puma (Felis concolor), andean cat (Felis jacobita), andean fox (Pseudalopex culpaeus), and quirquincho (Chaetophractus nationi).
Birds include the flamingos Phoenicopterus chilensis, Phoenicoparrus andinus, and Phoenicoparrus jamesi. Other birds include Pterocnemia pennata, Tinamotis pentlandii,and Chloephaga melanoptera (Ergueta and H. Gómez 1997). Two recently discovered reptiles of the genera Liolaemus were recorded in the Eduardo Avaroa Reserve.
Most of the endemic birds in the ecoregion are found in Polylepis forest and scrubs. Endemic birds found in this ecoregion and the Central Andean Wet Puna ecoregion include the endangered Ash-breasted tit-tyrant (Anairetes alpinus); the critically threatened royal cinclodes (Cinclodes aricomae); the Berlepsch’s canastero (Asthenes berlepschi), classified as vulnerable; and the line-fronted canastero (Asthenes urubambensis), scribble-tailed canastero (Asthenes maculicauda), short-tailed finch (Idiopsar bracyurus), and gray-bellied flower-piercer (Diglosa carbonaria), classified as species of least concern (Stattersfield et al. 1998b)
Endemic birds found in this ecoregion include the endangered Cochabamba mountain-finch (Poospiza garleppi); the maquis canastero (Asthenes heterura), rufous-bellied saltator (Saltator rufiventris), and chesnut canastero (Asthenes steinbachi) classified as vulnerable; the wedge-tailed hillstar (Oreotrochilus adela) and Tucuman mountain-finch (Poospiza baeri), classified as near threatened; and the citron-headed yellow-finch (Sicalis luteocephala) and bare-eyed ground-dove (Metriopelia morenoi), classified as a species of least concern (Stattersfield et al. 1998a)
Other endemic fauna includes an amphibian - Telmatobius huayra (Ergueta and H. Gómez 1997).
The Andean puna has been highly affected by livestock grazing for centuries (Ribera Arismedi 1992). The natural vegetation has been severely affected by grazing, burning, firewood collection and clearance for cultivation. The camelids, goats and sheep in the area degrade the herbaceous vegetation, making the life cycle for the plants difficult to complete (UNESCO 1981). The clearing of Polylepis forest for agriculture, firewood collection, and burning for pasture is an important threat to the endemic fauna, especially birds.
There are some protected areas within this ecoregion; most of them were created as faunal reserves. Eduardo Avaroa Andean Faunal National Reserve (IUCN category IV) of 714,745 ha, is an area principally for the protection of birds that inhabit the different lagoons in the Reserve (Ergueta and H. Gómez 1997). Several censuses of the flamingo population in this reserve registered 26,600 individuals (Rocha 1994). Sajama National Park (IUCN category II) of 100,230 ha, is one of the most diverse Andean Parks in the ecoregion with 25 species of mammals registered. This park includes a forest of Polylepis with trees up to 5-meters high. Olaroz-Cauchari Flora and Fauna Reserve (IUCN category VI) has an area of 180,000 ha.
Types and Severity of Threats
Polylepis forests has been destroyed and degraded throughout the region. The overuse of Polylepis tarapacana, and Azorella compacta for fuelwood threatens these two species (Ergueta and H. Gómez 1997). Mining activities in the Cordillera Occidental pollute the water bodies and poorly drained areas.
Justification of Ecoregion Delineation
This dry puna ecoregion of the central Andes is characterized by a dry climate and a number of endemic species. In Bolivia, out linework follows Ribera et al. (1994), from who’s classifications we lumped the following: "high Andean semi-desert", "dry puna", "desert puna", "halophytic prairie", and "salt flats". For portions extending into Argentina and Chile we referred to the classifications scheme of UNESCO (1980), and our linework lumps their "Andean caespitose herbaceous community (very dry puna)" and "subdesert semi-deciduoud, facultative deciduous, shrubland (halophye communities". Reference was also made to Daniele and Natenzon (1994), Morello (1968), and Carbrera (1976).
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Prepared by: Claudia Locklin
Reviewed by: In process