Location and General Description
The Córdoba Montane Savannas ecoregion is found within the provinces of Córdoba and San Juan (Olson et al. 2000, Anon. 1980). The northern, southern, western and eastern boundaries of this ecoregion terminate approximately at the 290 and 330 west latitudes and 660 and 630 south longitudes, respectively (Anon. 1980). Located approximately 400 km east of the main Andes chain, the Sierras Centrales consists of eight isolated Andean relict mountains with more than 2,000 m in elevation. This ecoregion encompasses the Sierra Grande de Cordoba, Sierra de San Luis, Sierra de Valle Fértil, Sierra de Volasco and several smaller mountaintops, with the latter extending more than 3,000 m in elevation at Monte Corralitos. Within the mountains there are plains such as the Pampa de Achala (Stattersfield et al. 1998). Annual rainfall is between 500-900 mm, but some areas receive 1100 mm or more (Davis et al. 1997). Temperature ranges are variable, with a mean around 17°C (Davis et al. 1997).
The Sierras’ isolation from the Andes by dry lowlands is one of the unique characteristics of this ecoregion. According to Davis et al. (1997) this upland Chaco ecoregion has three basic vegetative zones. The dry sunny areas up to 1,800 m contain forest dominated by Schinopsis haenkeana, while around the same elevation on shady cooler slopes, the dominant species are Lithrea ternifolia with Fagara coco. Above 1,800 m on shallow soil, grasslands of Festuca hieronymi and species of Stipa grow. There are about 190 species found in this high elevation grassland including many rare and/or endemic species (Davis et al. 1997). (Stattersfield et al. 1998, Narosky and Yzurieta 1989).
Because of the isolated nature of this unique ecoregion potential speciation and endemism are high. For example, there are approximately 12 subspecies of birds endemic to this ecoregion (Nores and Yzurieta 1983, Bucher and Nores 1988, Stattersfield et al. 1998). There are at least two species of Cinclodes (Furnariidae) endemic to this ecoregion. The Córdoba Cinclodes (Cinclodes comechingonus) is found at elevations ranging from 1,600 to 2,800 m, and it inhabits patches of Polylepsis australis that are close to water (Stattersfield et al. 1998). Olrog’s Cinclodes (C. olrogi), inhabits areas slightly lower, from 1,500 to 2,400 m, where there are open, grassy rock formations that typically fringe streams and lakes (Stattersfield et al. 1998). Cinclodes comprise a terrestrial group of birds that are associated with streams, and considered a striking example of parallel evolution when considering Eurasian and American Dippers in the family Cinclidae.
The Andean tinamou (Nothoprocta pentlandii), Andean condor (Vultur gryphus), olive-crowned crescentchest (Melanopareia maximiliani), cliff flycatcher (Hirundinea ferruginea), stripe-capped sparrow (Aimophila strigiceps) and black and rufous warbling finch (Poospiza nigrorufa) are just a few of the many bird species found in this ecoregion (Bucher and Nores 1988, Stattersfield et al. 1998, Narosky and Yzurieta 1989).
In terms of mammals, at least one species, the Hensel’s short-tailed opossum (Monodelphis henseli) is likely to be endemic to this region of Argentina (Olrog and Lucero 1980), though current taxonomic validity is uncertain. This region exceeds the latitudes of most tropical bats (e.g., Emballonurids, Phyllostomids, etc.), with the likely exception of the common vampire bat (Desmodus rotundus) which follows cattle colonization throughout Latin America. It is likely that the more temperate families of bats (e.g., Vespertilionids and Molossids) are present.
Primarily due to inaccessibility, this ecoregion is not currently jeopardized (Bucher and Nores 1988). The Córdoba Montane Savanna ecoregion's viability however, is of concern. The threat level is accentuated because the ecoregion is restricted to these small highland areas; therefore, any development is likely to destroy a large percentage of this ecoregion. Though not greatly threatened at present, the chief threat is moderate habitat loss due to overgrazing (Nores 1995). At present, the only protected area in the region is the Quebrada del Condorito National Park (IUCN category II) (Stattersfield et al. 1998).
Types and Severity of Threats
The Córdoba Montane Savanna remains vulnerable due to high levels of endemism harbored in this unique habitat (Bucher and Nores 1988); minimal habitat disturbance can equate to major population declines of unique endemics. Populations of the Andean Condor (Vultur gryphus) for example appear to have declined since the building of roads (Bucher and Nores 1988). While overgrazing and development for grazing lands might not have a current effect on most of the endemic birds (Stattersfield et al. 1998), the long-term effects remain to be seen, particularly on mammalian fauna which are also suffering from over-hunting.
Justification of Ecoregion Delineation
These elevational patches of savanna occur along the Córdoba Mountains of Argentina. Their archipelago-like distribution and isolation have resulted in a number od endemic species. The deliniations for the Córdoba Montane Savanna were derived from Daniele and Natenzon (1994), and linework follows their Pastizales y Bosques Serranos region. Other resources consulted include Cabrera (1976) and Morello (1968).
Anon. 1980. Time-Hammond World Atlas. Hammond, Inc., Maplewood, N.J.
Bucher, E.H., and M. Nores. 1988. Present status of birds in steppes and savannas of Northern and Central Argentina. ICBP Tech. Publ. 7: 71-79.
Cabrera, A.L. 1976. Regiones fitogeográficas Argentinas. Enciclopedia Argentina de Agricultura y Jardinería, Second Edition, Vol. II, Buenos Aires, Argentina.
Daniele, C., and C. Natenzon. 1994. Regiones Naturales de la Argentina. Draft map. Argentina National Parks Department, Buenos Aires, Argentina.
Davis, S.D., V.H. Heywood, O. Herrera-MacBryde, J. Villa-Lobos, and A.C. Hamilton. 1997. Centres of Plant Diversity: A guide and strategy for their conservation. Information Press, Oxford, UK.
Morello, J. 1968. La vegetación de la República Argentina, No. 10: Las grandes unidades de vegetación y ambiente del Chaco Argentino. Buenos Aires, Argentina.
Narosky, T., and D. Yzurieta. 1989. Birds of Argentina and Uruguay. Vazquez Mazzini Buenos Aires, Argentina.
Nores, M. 1995. Insular biogeography of birds on mountaintops in northwestern Argentina. J. Biogeogr. 22: 61-70.
Nores, M., and D. Yzurieta. 1983. Especiación en las Sierras Pampeanas de Córdoba y San Luis (Argentina), con descripción de siete nuevas subespecies de aves. Hornero Extr.: 88-102.
Olrog, C. C., and M. M. Lucero. 1980. Guiá de los Mamiferos Argentinos. Fundación Miguel Lill, Tucuman, Argentina.
Olson, D., E. Dinerstein, P. Hedao, S. Walters, P. Allnutt, C. Loucks, Y. Kura, K. Kassem, A. Webster and M. Bookbinder. 2000. Terrestrial Ecoregions of the Neotropical Realm (map). Conserv. Sci. Program, WWF-US, DC.
Stattersfield, A.J., M.J. Crosby, A.J. Long and D.C. Wege. 1998. Endemic Bird Areas of the World: Priorities for Biodiversity Conservation. The Burlington Press Ltd, Cmabridg, U.K.
Prepared by: Dr. Dan Brooks
Reviewed by: In process