Location and General Description
The Central Andean Wet Puna ecoregion is located in the Andean Mountains of Peru and eastern Bolivia. This elongated ecoregion extends through most of the Peruvian departments of Huancavelica, Ayacucho, Apurímac, and Puno; large areas of the departments of Cajamarca, La Libertad, Ancash, Huanaco, Paso, Junin, Lima, Ica, Arquipa and Cusco; and smaller areas of Lambyeque, Moquegua, and Tacna. The topography in this ecoregion is complex, as the Andean mountain range divides into a series of ridges with a large plateau in between called the Altiplano (Kricher 1997). In the northern section of the ecoregion, the wet puna is fragmented, including only the higher elevations of low mountain ranges (Young et al. 1997). The northern section of the ecoregion includes the Cordillera Blanca, Cordillera Negra, Cordillera Vilcabamaba, Cordillera Carabaya. In Bolivia, the ecoregion is found in the south of the department of La Paz. The Andes divides into two mountain systems- Cordillera Occidental and the Cordillera Oriental- close to the border of Peru and Bolivia. The Cordillera Oriental is in turn divided into two Cordilleras, the Real and the Central. The Cordillera Real contains various mountain chains, among which are the Cordillera de Apolobamba, Cordillera de Muñecas, Cordillera de La Paz, and Cordillera de Tres Cruces (Montes de Oca 1997). The highest peak of the ecoregion is Nevado Huascaran (6,745 m) in Peru.
The Central Andean wet puna comprises magnificent mountains and a high plateau. The area includes three subregions: the high andean puna, wet puna, and wet montane grassland. The high Andean puna lies between 4,200 to 5,000 m in elevation. The area is extremely oligothermic, characterized by having summer during the day and winter at night. The extreme shift of temperature during the day has been a selective force in the adaptation of plants to this environment. Nightly freeze during the entire year is one of the environmental stresses the plants face (Smith 1994). The annual precipitation at high elevations is less than 700 mm. Precipitation occurs mainly as snow and hail.
The wet puna is located in the Altiplano at elevations ranging from 3,700 to 4,200 masl. The humidity in the Altiplano varies from north to south. The areas in the north surrounding Lake Titicaca have eight wet months, and the areas in the south have one to two wet months. The average precipitation in the Altiplano ranges from 500 to 700 mm. The average annual temperature is low, ranging from 5 to 7 oC; the temperature varies considerably on a daily basis, with night frost periods from March to October.
The wet montane grasslands are located in the eastern section of the ecoregion, at an elevation ranging from 3,800 to 4,200 masl. These grasslands are located in steep mountains with deep valleys, which originated from glaciers. The grasslands are more humid than the puna (Ribera Arismedi 1992).
Most of the ecoregion consists of Tertiary and Quaternary volcanic bedrock. The ecoregion contains a great heterogeneity in puna substrates depending on the bedrock underneath. Areas in northern Peru have deposits of glacial loess as deep as one meter. Glacial moraines and associated landforms are present throughout the puna. Many of the highlands above 4,000 masl were covered by ice, and some glacial tongues moved down to 3,000 masl (Young et al. 1997).
The ecoregion contains snow-capped peaks, glacial lakes, and several rivers that originate in the Cordilleras. The biggest lake in the ecoregion is Lake Titicaca, which is the highest lake in the world, at an elevation of 3,800 masl. Its main tributaries in Bolivia are the Suches and Tiwanacu rivers.
Grasses are conspicuous in this ecoregion, especially the following genera: Agrostis, Calamagrostis, Festuca, Paspalum and Stipa, and in more humid areas Chusquea and Cortaderia. Plants other than grasses that predominate include Azorella, Baccharis, Daucus, Draba, Echinopsis, Gentiana, Geranium, Lupinus, Nototriche, Plettekea, Valeriana and Werneria (Asteracae); Carcadamine, Draba, and Weberbauera (Brassicaceae); Lysipomia (Campanulaceae); Arenaria, Cerstium, and Pycnophyllum (Caryophyllaceae); Acaena, Alchemilla, and Potentilla (Rosaceae); Arcytophyllum, and Galium (Rubiaceae); Agalinis, Bartsia, and Calceolaria (Scrophulariaceae) (Young et al. 1997).
The high Andean puna includes species of grasses such as Festuca dolichopylla, Stipa ichu, Calamagrostis spp. Other plants with prostrate and roseate life forms are Hypochoeris spp., Lachemilla spp., Pycnophyllum spp., Azorella spp., and Aciachne pulvinata (Ribera Arismedi 1992).
The wet puna is covered by grasses and shrubs. Sedges and rushes dominate areas with poor drainage. Below 4,000 masl, vegetation in wet areas includes the following genera: Carex, Juncus, Oreobolus and Scirpus. Above 4,000 masl, the vegetation in wet areas, 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). Common trees in the area are Buddleja coriacea and Polylepis spp. A giant rosette in the ecoregion is Puya raimondii. Puya is the most primitive and only genus of the Bromeliaceae in the Andes (Miller 1994). The wet puna also includes small mountain chains with microclimates, where some of the following species are found: Satureja boliviensis, Calceolaria spp., Mutisia ledifolia, Senecio spp., Senna aymara, and Ephedra americana (Ribera Arismedi 1992).
The wet montane grasslands in the region encompass species not found in the wet puna vegetation. Some of these species are Gnaphalium spp. Blechnum loxense, Loricaria sp., and Achirocline sp.
According to Young (1997), there are 1,000-1,500 vascular plants accounted for on the Peruvian side of the wet puna. Monocotyledons represent 30-40% of the flora. The dicotyledons are represented by more than 175 genera, including the diverse and prominent families mentioned earlier.
Endemic plants that have their centers of diversity in this ecoregion are Culcitium, Perezia and Polylepis. Other endemic species are Alpaminia and Weberbauera (Brassicaceae) and Mniodes (Asteraceae).
Animals that live at high elevation show various adaptations both to the elevation, and to the extreme temperatures. The Andean camelids are found in these and other ecoregions, including the vicuña (Vicugna vicugna), llama (Lama glama), guanaco (Lama guanacoe), and alpaca (Lama pacos). The vicuña, once endangered, is in the lower risk category of the IUCN red list. Larger mammals include the puma (Felis concolor), and the andean fox (Pseudalopex culpaeus). Some bats include Histiotus montanus and Lasiurus cinereus; these two species hibernate.
The Central Andean Dry Puna ecoregion is rich in endemic avifauna. Endemic species throughout the region include the endangered Ash-breasted tit-tyrant (Anairetes alpinus); the critically threatened royal cinclodes (Cinclodes aricomae); Berlepsch’s canastero (Asthenes berlepschi) classified as vulnerable; line-fronted canastero (Asthenes urubambensis), olivaceous thornbill (Chalcostigma olivaceum), 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. 1998).
Endemic birds, found in the northern section of the ecoregion in Peru’s Cordillera Blanca Cordillera Negra, Cordillera Vilcabamba, and Cordillera de Vilcanota, live principally in dense montane scrub and shrubby forest with cacti. While most of these birds live in the puna region, some of them live in subtropical and temperate zones. These birds include the plain-tailed warbling-finch (Poospiza alticola), and rufous-breasted warbling-finch (Poospiza rubecula) classified as endangered; Taczanowski’s tinamou (Nothoprocta tacaznowskii), and white-cheeked cotinga (Zaratornis stresemanni) classified as vulnerable; Kalinowski’s tinamou (Nothoprocta kalinowskii), and white-browed tit-spinetail (Leptasthenura xenothorax), classified as critical; rufous-eared brush-finch (Atlapetes rufigenis) classified as near threatened; white-tufted sunbeam (Aglaeactis castelnaudii), bearded mountaineer, (Oreonympha nobilis), striated earthcreeper (Upucerthia serrana), rusty-fronted canastero (Asthenes ottonis), rusty-bellied brush-finch (Atlapetes nationi), chesnut-breasted mountain-finch (Poospiza caesar), and brown-flanked tanager (Thlypopsis pectoralis), classified as least concern status species (Stattersfield et al. 1998).
The southern section of the ecoregion includes the Cochabamba mountain-finch (Poospiza garleppi) classified as endangered; Berlepsch’s canastero (Asthenes berlepschi), maquis canastero (Astenes heterura), and rufous-bellied saltator (Saltator rufiventris) classified as vulnerable; citron-headed yellow-finch (Sicalis luteocephala) classified as near threatened; scribble-tailed canastero (Asthenes maculicauda), short-tailed finch (Idiopsar brachyurus), and grey-bellied flower-piecer (Diglossa carbonaria) classifed as species of least concern. Asthenes berlepschi is vulnerable because of its limited habitat range near Nevado Illampu.
This ecoregion also has endemic birds located in small areas, such as the Junin Puna located in central Peru. The endemic birds of the Junin Puna are restricted to areas surrounding Lake Junin and the central Huancavelica department. These birds include the Junin grebe (Podiceps taczanowskii), Junin rail (Laterallus tuerosi), black-breated-hillstar (Oreotrochilus melanogaster), dark-winged miner (Geositta saxicolina), white-bellied cinclodes (Cinclodes palliatus), and Junin canastero (Asthenes virgata). Pollution and changes in the water level of the Lake have affected three of the endemic birds in this area. Podiceps taczanowskii is found in open freshwater lakes and ponds with submerged vegetation; Cinclodes palliatus has very specific habitat requirements such as mineral-rich bogs, rocky outcrops and slopes below glaciers; and Laterallus tuerosi inhabits Juncus zone fringing marshes (Stattersfield et al. 1998). The Podiceps taczanowskii population declined drastically with the decline of the frog and fish populations in the Lake (Elton 2000).
The Altiplano has been highly affected by livestock grazing for centuries (Ribera Arismedi 1992). The natural vegetation has been severely affected by livestock 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 protected areas in this ecoregion include, from north to south, the Huascaran National Park, Lake Junin, Lake Titicaca and Ulla-Ulla reserves. The Huacaran Reserve (IUCN category II), a Biosphere Reserve of 340,000 ha, is located in the Cordillera Blanca. This Park contains the highest peak of Peru Huascaran (3,745 m), other 26 snow-capped peaks above 6,000 m, 663 glaciers, 296 lakes and 41 rivers that discharge into the Santa, Pativilca and Marañon watersheds (UNEP World Conservation Monitoring Centre 1995). Lake Junin National Reserve (IUCN category V) with 53,000 ha is an important area with confined bird species. Even though this is a reserve, this fact has not deterred the pollution and water-level changes in the Lake from mining operations. Manu National Park (IUCN category II, 1,532,806 ha) contains 18,400 ha of puna vegetation. Lake Titicaca Reserve (IUCN category V, 36,180 ha) protects the Lake on the Peruvian side. National Faunal Reserve Ulla-Ulla (IUCN category IV, 150,000 ha) is located on the border of Peru and Bolivia. Ulla-Ulla is a biosphere reserve that protects various animals. The most important is the vicuña (Vicugna vicugna), which has been protected since 1965. The Vicuña population declined significantly due to hunting to get the fine wool fiber, but it has recovered in the past decade. The population of the vicuñas in 1996 was of 6,500 individuals. Other National Reserves and Sanctuaries include Calipuy, Pampa Galeras, Salina-Agua Blanca, Huayllay, and Ampay.
Types and Severity of Threats
The puna is one of the most altered regions in Peru and Bolivia. The region has been inhabited for centuries, triggering changes in the natural vegetation. Polylepis forests are threatened by agriculture and collection of firewood for heating and cooking (Ergueta and H. Gómez 1997). Overgrazing by livestock has degraded the vegetation and caused soil erosion. Pollution due to mining activities is present in water bodies and poorly drained areas. The restricted populations of aquatic and semi-aquatic vegetation are threatened by this kind of pollution (Young et al. 1997).
Justification of Ecoregion Delineation
This wet puna ecoregion of the central Andes is characterized by a semi-dry climate and a number of endemic species. In Bolivia, out linework follows Ribera et al. (1994), who classify this as "humid puna". In Peru we followed the classification of Instituto Geográfico Nacional (1987), and linework follows their "puna" ecoregion. From this region we seperated out the Central Andean Puna ecoregion, whose intermediate climate and subsequent unique species assemblages separate if from both the dry and wet puna ecoregional classifications (see Central Andean Puna ecoregion for justification). In the northern extent of this classification we also seperated páramo vegetation.
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Prepared by: Juan Carlos Riveros Salcedo and Claudia Locklin
Reviewed by: In process