The Patagonian grasslands (NT0804) is an ecoregion in the south of Argentina and Chile. The grasslands are home to diverse fauna, including several rare or endemic species of birds. There are few protected areas. The grasslands are threatened by overgrazing by sheep, which supply high-quality merino wool. Efforts are being made to develop sustainable grazing practices to avoid desertification.
The ecoregion in South America is divided into a northern mainland section and southern Tierra del Fuego Island section by the Strait of Magellan.
The grasslands cover terrain of low mountains, plateaus and plains.
The soils are rich, with high levels of organic material.
Average annual rainfall is 300 to 400 millimetres (12 to 16 in).[1]
Mean temperatures in the far south of Tierra del Fuego are 5.4 °C (41.7 °F), but temperatures may fall below −20 °C (−4 °F).[5]
The ecoregion holds important wetlands including the Tero marsh and lagoons, Rio Pelque marsh, Lago Argentino, Puerto Bandera lagoons, Lake Viedma, Meseta del Tobiana lagoons and Escarchados lagoons.
In the coastal region important wetlands include Río Santa Cruz, Monte León, Río Coig, Ría Gallegos, Cabo Vígenes, Bahía San Sebastián, Río Grande, Mitre Peninsula, Beagle Canal and Isla of the Estados.[1]
The northern part of the ecoregion is covered by tundra grasslands.
In the center there are high latitude Andean meadows and in the far south there are deciduous thickets.
On the Falkland Islands there are swamp forests.[1]
The World Wildlife Fund gives the ecoregion a status of "Vulnerable".
Few people live in the ecoregion.
However, grazing livestock and introduced animals have destroyed the natural grassland, particularly tussock grass.[1]
Where the sparse vegetation has been damaged the soil is exposed to erosion.[1]
Overgrazing by merino sheep is turning the grassland into a desert.[6]
In the past Guanacos were the only large grazing animal, and imposed little stress on the semi-arid grasslands.
Commercial sheep farming, which began at the end of the 19th century, has had a drastic impact.
Palatable grasses have been progressively eliminated, replaced by unpalatable woody plants.[7]
The natural tussock grass is an important resource for endemic birds.
Three birds species at risk are the critically endangered hooded grebe (Podiceps gallardoi), the rare ruddy-headed goose (Chloephaga rubidiceps) and the near threatened striated caracara (Phalcoboenus australis), which has suffered from over-hunting.[1]
Conservation
The ecoregion has few protected areas.
They include Dicky Private Wildlife Reserve (Refugio Privado de Vida Silvestre Dicky) and Magallanes National Reserve on the mainland, and Reserva Costa Atlántica in Tierra del Fuego.[1]
The Patagonian Grasslands of Argentina Conservation Project, organized by The Nature Conservancy, is trying to develop sustainable grazing practices in partnership with scientists and landowners, but it is a challenge to find economic incentives.[6]
An Argentine company has worked with The Nature Conservancy to develop protocols and measurements for sustainable grazing, which can be used in branding clothes made of Patagonian wool. The theory, which is controversial, is that if sheep are moved frequently to emulate herds of wild animals avoiding predators they may actually help regenerate the grasslands.
The decisions on where and how fast to move them depend on many ecological factors, and some academics are skeptical about whether real benefits can be achieved.[8]
Notes
^The World Wildlife Fund (WWF) "WildFinder" application shows the grasslands as part of the Patagonian steppe.[2] This is inconsistent with the WWF's detailed description of the grasslands as a separate ecoregion.[1] However, the term "Patagonian grasslands" may be used to cover all grasslands in Patagonia, including the steppe and the more southern parts.[3] This article takes the narrow definition of the WWF NT0804 ecoregion.
