Córdoba montane savanna

• Category: Grassland, Tundra, and Human Biomes.
• Geographic Location: South America.
• Summary: The isolation of this diverse mountainous ecoregion has protected it from environmental threats; it is thriving, but only one small region has been declared protected land.

The Córdoba montane savanna ecoregion includes parts of the Córdoba and San Juan provinces of Argentina, roughly between 29 degrees and 33 degrees west longitude and 63 degrees and 66 degrees south latitude. The ecoregion consists of the isolated mountain chain of the Sierra Centrales, about 250 miles (400 kilometers) east of the main Andes chain, from which it is separated by a dry lowlands area. The Córdoba itself comprises the Sierra Grande de Córdoba, Sierra de San Luis, Sierra de Valle Fertil, Sierra de Volasco, and four smaller mountaintops.

The area includes woodlands and rocky areas, grasslands, deep gorges, and plains such as the Pampa de Achala. As a result of the mountains' isolation, the local flora are rich in endemic species (those not found elsewhere on Earth). The temperature varies but is predominantly temperate to cool; annual rainfall varies from 20 to 43 inches (500 to 1,100 millimeters), depending on the local topography.

Potential Environmental Threats

The ecoregion faces no current jeopardy, thanks largely to its isolation, but it is fragile. Because the savanna developed in isolation, any development is likely to cause significant changes to the ecosystem and its diversity. It is likely that a large percentage of the species living in delicate balance with one another would be unable to adapt swiftly to major changes such as newly introduced species (whether competitors or predators), or diversion of natural resources.

Habitat loss from overgrazing is considered one of the biggest potential threats. Studies of natural montane grasslands responses have found that both high-intensity agricultural activity over a short period (such as commercial endeavors by major business interests), and lower-intensity high-frequency activity (such as subsistence farming and more traditional smaller-scale farming) have a major impact on species richness and ecosystem balance. By contrast, simple grazing, so long as it does not lead to overgrazing, has comparatively little effect on the ecosystem and is much less likely to result in the invasion of new species.

Additional stress may come in the form of global warming. Higher average temperatures will cause greater evaporation rates, faster glacial and snowpack melt, and lower average water levels along riparian stretches of the biome. Species migration or disappearance will be a real concern, once these trends begin to accumulate. With the already-isolated nature of these montane biological niches, these factors are projected to contribute to the acceleration of habitat fragmentation.

Because the ecoregion faces no current severe threats, the only protected area is Quebrada del Condorito National Park.

Wildlife

The Córdoba montane savanna region is home to a large number of endemic species. A total of 12 bird species and subspecies are native to the savanna; species found here include the Andean tinamou (Nothoprocta pentlandii), olive-crowned crescentchest (Melanopareia maximiliani), cliff flycatcher (Hirndinea ferruginea), stripe-capped sparrow (Aimophila strigiceps), and rufous warbling finch (Poospiza nigrorufa).

Among other songbirds, the Córdoba Cinclodes (Cinclodes comechingonus), found at elevations of 5,250–9,200 feet (1,600–2,800 meters); and Olrog's Cinclodes (C. olrogi), found at 4,920–7,880 feet (1,500–2,400 meters) among grassy rock formations near lakes and streams, are endemic to the region and evolved similarly to the Eurasian and American bird family Cinclidae. Cliff walls are used as nesting sites by the peregrine falcon (Falco peregrinus) and black-chested buzzard eagle (Geranoetus malanoleucus). Also present is the Andean condor (Vultur gryphus).

The Hensel's short-tailed opossum (Monodelphis henseli) is believed to be endemic to the region. Temperate families of bats (Vespertilionids and Molossids) also are found in the Córdoba montane savanna. Although the latitude is too high for most tropical bats, the exception is the vampire bat (Desmodus rotundus), which can be found in most places in Latin America where there are cattle on which they can feed. The plain is home to the endemic Achalan frog (Odontophrynus achelensis), which faces the threat of habitat loss due to grazing, and the two Achalan toads Rhinella achalensis (also called the Córdoba toad) and Chaunus achalensis.

The Andean fox (Pseudalopex culpaeus), a false fox (fox-like canid outside the Vulpes genus) also called the red fox or zorro rojo, was once an endangered mammal of the region. It preys on the many rodents and hares that roam the area. One of the red fox's competitors is the puma (Felis concolor). Other animals of the Córdoba montane savanna are Geoffroy's cats (Oncifelis geoffroyi); ferrets (Mustela furax); and colocolos (Oncifelis colocolo), spotted and striped wildcats that may be nocturnal and that prey on the plentiful wild guinea pigs of the region.

In 2010, a new species of Akodon, a genus of rodent, was discovered. The Akodon genus is unique to South America and found mainly along the Andes. The new species, Akodon viridescens, is not quite endemic to the Córdoba montane savanna, as it can be found in northwestern Argentina's Cuyo region.

Surrounded by the mountains is the plain of Pampa de Achala, which enjoys a microclimate and is home to some endemic species, most of which may still be undiscovered.

Vegetation

Even apart from the endemic species, much of the diversity here comes from the meeting of the surrounding mountains' plant and animal populations in this common space. Some of the trees found on the plain are found only on mountain slopes, and the same is true of various small mammals and insects that use them for habitats or food.

The most prominent vegetation of the Córdoba Montane Savanna biome is the grass, which is coarse and of low nutritive value for grazing livestock or wild animals. Stands of tabaquillo (Polylepis australis) and mayten (Maytenus boaria) trees grow here as well. The tabaquillo is endemic to the ecoregion and has adapted to the cold winters by producing rough sheaths of loose, papery bark that surround the trunk and insulate the tree from cold temperatures. Tabaquillo forests are among the most endangered in the world; there is a strong negative correlation between seed viability and the proximity of human activity, and individual trees grow poorly, thriving only when many of their number are present. Maytens have fared better and are found throughout Argentina as well as Chile. Honey from the tree is collected commercially, and grazing cattle feed on the tender leaves. The Argentine maytens are especially hardy and known for their drought resistance. They are often found growing in conjunction with the endangered understory plant Adiantum gertrudis, one of the many species of ferns growing in the region, noted for the fine hairs covering its fronds.

Bibliography

Braun, J., M. Mares, B. Coyner, and R. Van Den Bussche. “New Species of Akodon From Central Argentina.” Journal of Mammalogy 91, no. 2 (2010).

Diaz, Sandra, Alicia Acosta, and Marcelo Cabido. “Community Structure in Montane Grasslands of Central Argentina in Relation to Land Use.” Journal of Vegetation Science 5, no. 4 (1994).

Fernández, Pedro D., et. al. “Grasslands and Open Savannas of the Dry Chaco.” Encyclopedia of the World's Biomes, 2019, doi.org/10.1016/B978-0-12-409548-9.12094-9. Accessed 16 Nov. 2024.

Stattersfield, A. J., M. J. Crosby, A. J. Long, and D. C. Wege. Endemic Bird Areas of the World: Priorities for Biodiversity Conservation. Cambridge, UK: Burlington Press, 1998.