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The High Andean Lakes are unique freshwater systems located at very high altitudes. They contain many endemic fish and mollusk species. One of the tallest and longest mountain chains on Earth, the Andes, was formed millions of years ago. Nearly 20,000 feet high (6,000 m) in some areas, the Andes contain a wide variety of ecosystems, including dozens of lakes that are home to endemic species.
Freshwater and saline lakes are scattered throughout this ecoregion, including some found at the highest elevations in the world. Some lakes lie in wide, deep basins while others occupy small depressions in the ground. The largest and deepest, Lake Titicaca, lies at an elevation of 12,500 feet (3,800 m) and contains freshwater. In contrast, Lake Poopó is shallow, flat, and very salty.
These high-altitude lakes, such as Lake Titicaca in Peru and Bolivia, are not particularly rich in species but they contain many endemic fish and mollusks. Numerous Orestine fishes occur in these still-water habitats, such as Orestias chungarensis, O. laucaensis, and O. pentlandii. The climbing and pencil catfishes are also characteristic of the high-altitude lakes and streams of the Andes. The threatened James and Andean flamingos, as well as the endemic horned coot and more common Chilean flamingo, live in this ecoregion, too.
These high elevation lakes are fragile, and are threatened by runoff of sediments and contaminants from mining, agriculture, and livestock grazing. Water quality has declined in several lakes due to the input of untreated sewage and pollution from industrial sources. Overfishing and introduction of exotic species threaten fish populations, particularly in Lake Titicaca.
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