Central Andean Puna grasslands
The Central Andean Puna grasslands are a unique ecosystem located in the high-altitude regions of the Andes Mountains, spanning southern Peru, Bolivia, and northern Argentina. These grasslands, characterized by their mountainous terrain, include a diverse array of vegetation such as shrubs, grasses, and specialized plants like yareta, which thrive in harsh, cold environments. The Puna is situated at elevations between approximately 9,843 and 15,748 feet (3,000 to 4,800 meters), with conditions that vary significantly from wet to dry across different regions.
The landscape features a combination of high mountains, glacial valleys, wetlands, and plateaus, supporting various flora and fauna adapted to extreme conditions. Due to the region's complex topography and climatic variability, the Puna is fragile and sensitive to ecological changes. It plays a crucial role in the hydrology of the Andes, acting as a headwater for rivers that feed into larger basins like the Amazon.
However, the Puna ecosystem faces significant threats from global climate change, including altered precipitation patterns and glacial melt, which could disrupt the delicate balance necessary for local communities that depend on these resources for agriculture and water supply. Understanding the Puna grasslands is key to addressing these environmental challenges and promoting sustainable management practices in this vital region.
Subject Terms
Central Andean Puna grasslands
- Category: Grassland, Tundra, and Human Biomes.
- Geographic Location: South America.
- Summary: The Puna grassland is a mountain grasslands and shrublands biome. The dominant vegetation consists of shrubs, often also including grasses, herbs, and geophytes (plants with nutrition-storing abilities often manifesting as underground bulbs).
The Central Andean Puna grasslands occupy Peru's central Andes Mountains and extend south as far as northern Argentina and Chile. This type of ecosystem is considered to be one of Peru's eight natural regions. The slopes and ravines of greater altitude and slope, including forest residues (the Polylepis species of queñual) harbor a large part of the diverse flora and fauna found in the area.
The overall territory of high-Andean grassland, located at an altitude range between 9,843 and 15,748 feet (3,000 and 4,800 meters), runs throughout the Andes, starting at the border with Ecuador, crossing through all of Peru, and reaching Bolivia. This biome is called a jalca, or páramo. It is at a lower altitude in Piura (10,171 feet or 3,100 meters) and Cajamarca (10,499 feet or 3,200 meters) areas, and extends to a latitude of approximately nine degrees south.
The central Andean puna is a mountain grasslands and shrubland ecoregion in the Andes of southern Peru, Bolivia, and northern Argentina. The landscape in this ecoregion consists of high mountains with permanent snow and ice, meadows, lakes, plateaus, and valleys. It transitions to the central Andean wet puna to the north and the central Andean dry puna to the south. Elevations range from 10,499 to 21,654 feet (3,200 to 6,600 meters). The landscape is characteristically mountainous, with snowy peaks, U-shaped glacial valleys or high headwater valleys, plains, and lakes. The puna's plateaus are dominated by a landscape that combines typical prairie grassland with patches of forest, scrubs, and wetlands, limited by the permanent snow line of the jalca region.
Peruvian Differences
Peru has different climate regimes and two types of puna: the wet (center) and dry (southwest). Annual rainfall varies widely, ranging from 6 to 31 inches (150 to 800 millimeters) from north to south. Other features of the puna landscape and vegetation are groups of Puya Raimondi remnants, high-altitude wetlands, and bush and shrub vegetation consisting of Baccharis and Gynoxis species; denser formations of the Oreoboluys and Calamagrostis species, reminiscent of highlands artificial grass; hundreds of high-altitude lakes; and a high-Andean alpine vegetation zone formed by very slow growing plants that have adapted to cold weather and the harsh highlands environment.
The Peruvian Andes, because of its sheer size, orientation, altitude, and topography, is the main physical system that structures the distribution of rainfall. Due to the location of deserts and plateaus as wet basin headwaters, its role in the continental water regulation system is essential. Temperatures in the Andes vary daily between extreme highs and lows, with a marked dry season that is more pronounced south of Peru. In the daily cycles and within seasons, temperatures fall below 32 degrees F (0 degrees C), with conditions of frost and hail making agriculture and even livestock breeding high-risk ventures. Overall rainfall ranges from 8 to 39 inches (200 to 1,000 millimeters), affecting water availability in both the microtopography and climate processes that are global in nature, which unexpectedly generate droughts and floods.
Puna, Páramo, and Jalca
The differentiation among the Puna, Páramo, and Jalca regions is debated among expercts, but among the general characteristics that differentiate these regions is the degree of dryness. The Puna grasslands are seasonal and dry since they do not receive sufficient rainfall to maintain a vegetation coverage, whereas Páramos are more like sponges that act like reservoirs of water in the form of permafrost. The Jalca has a cold climate with snow precipitation. This region is considered a transition area between the Páramos and the Puna because some vegetation from both regions can be found there.
These ecosystems occur in the tropical Andes, in the northern part of Peru, and in southern Ecuador. The landscape is quite rugged in the upper parts of the western Cordillera Mountains, with the presence of gallery forests, queñuales, quishuares, and alders forming part of the headwaters of the basin. The weather is cold, characterized by high soil moisture and permanent cloud cover, with frequent precipitation often exceeding 59 inches (1,500 millimeters) per year.
Puna Grasslands
The Puna grasslands are also located in the Andean highlands, but only from the Cordillera Blanca south, where the wet punas begin forming a transition zone between the jalca, or moor, and the dry Puna of Central and South America. It is difficult to establish a defined altitude at which the highlands begin, but they are generally considered to start at around 12,467 feet (3,800 meters) and can reach an altitude of 15,748 feet (4,800 meters). The Puna ecoregions extend into slots in the highest parts of the Andean mountain system, and their locations are critical in terms of their impact on lower areas. Because of the height of these ecoregions, the youth of their soils, and their complex topography, which is characterized by steep slopes prone to erosion, they are extremely fragile both biophysically and socially.
The strategic importance of this ecoregion lies in its position along the Andes as the headwater of innumerable peaceful rivers that form part of the Amazon Basin. As a result, strategic management affects conservation areas located downstream. In addition, these high grassland ecoregions can be seen as an ecological corridor connecting valleys that would otherwise be segmented. In the twenty-first century, concern has grown over glacial pullback that many see as a symptom of global climate change, another front in the challenge to establish a sustainable control regime to mitigate human effects on the ecological infrastructure. Global warming poses significant ecological concerns for Peru's Puna grasslands, primarily through potential impacts like altered precipitation patterns, increased temperatures, and glacial melt. This will lead to changes in vegetation composition, reduced water availability, and disruption to the delicate balance of this high-altitude ecosystem, important elements for local communities that are reliant on the Puna's resources for activities like grazing land and for their local water supply.
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