Northwestern Andean montane forests
The Northwestern Andean montane forests are a rich and complex ecosystem located in western South America, stretching from northwestern Colombia to Ecuador. Recognized as one of the most biodiverse forest regions globally, these forests host a myriad of plant and animal species, many of which are endemic, meaning they are found nowhere else on Earth. This unique biodiversity has evolved due to historical climatic shifts and geographic isolation, particularly following glacial periods that forced adaptation among various species.
The region experiences some of the highest rainfall levels in the world, contributing to its lush vegetation and diverse habitats. Among its notable inhabitants are the spectacled bear, the only surviving member of the short-faced bear family, and the mountain tapir, the smallest of tapir species that thrive in these montane environments. Both species play crucial roles in their ecosystem, particularly in seed dispersal and maintaining plant diversity.
Unfortunately, human activities have led to habitat loss, threatening these forests and their inhabitants. Issues such as deforestation for agriculture, urban development, and illegal wildlife trade have made conservation efforts increasingly urgent. The forests not only support a vast array of wildlife but are also integral to the cultural and ecological heritage of the region, emphasizing the importance of preserving such unique environments for future generations.
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Subject Terms
Northwestern Andean montane forests
Category: Forest Biomes.
Geographic Location: South America.
Summary: The northwestern Andean montane forests are among the most diversely populated forest regions in the world.
Among the most biodiverse forest regions in the world is the northwestern Andean montane forest. Consisting of tropical and subtropical moist broadleaf forests in a large area of western South America, from northwestern Colombia to Ecuador, the forest includes numerous animal and plant populations that were forced to readapt after glacial periods isolated them from their earlier ecoregions. Rainfall in this region is among the most plentiful in the world. The complex topography of the area and recurring altitudinal migration of vegetation as a result of shifts in climate have set up ideal conditions for speciation.
The result has been today's present diversity and an unusually high level of endemism (species evolved specifically to fit an isolated biome). The ecoregion is not only one of the most biodiverse on Earth, but also home to one the highest percentages of endemic species: Half of the plant species found here are found only here. Nearby ecoregions include the Magdalena Valley montane forests, Venezuelan Andes montane forests, Cauca Valley montane forests, Santa Marta montane forests, and Eastern Cordillera Real montane forests. The encroachment of human activity has interrupted the expanse of forest, as some of it has been cleared for farmland or settlements.
Iconic Bear Species
One of the important species of the region is the spectacled bear (Tremarctos ornatus), also known as the Andean bear, ukuo, or ucumari. The last surviving member of the short-faced bear family, which was common in the Middle and Late Pleistocene epoch, it is small for a bear species but the largest nontapir mammal in South America. Its short face, small ears (set far back), and facial markings make it faintly resemble a raccoon, though not all spectacled bears have spectacled facial coloring. Males are nearly twice as big as females.
The bears are nonterritorial but tend to live in isolation, and with the exception of mothers protecting their young, they are not known to attack humans; no human death by spectacled bear has been recorded. Spectacled bears build platforms in trees, as places to rest and to store food. The behavior may have developed during the Pleistocene epoch, when adult bears had more predators to conceal themselves from.
The bears rely more heavily on plants than most bear species do and are consumers of many plant food sources that other animals have difficulty opening or digesting, including cacti, palm nuts, orchid bulbs, forest fruit, and unopened palm leaves. They may travel to higher elevations in search of berries. Although meat normally makes up only about 5 percent of the bear's diet, its prey may include deer, cattle, and horses, and local farmers have been known to shoot bears on sight to protect their cattle.
One of the palms on which the spectacled bear feeds is the wax palm or white palm (Copernicia alba), found throughout South American forests, usually in dense, naturally occurring monocultures. The lightweight, semi-hard wood is used for utility poles, and the waxy coating of the leaves has long been used by native South Americans to make candles. Its globular fruit is a dark berry containing a long ovoid seed that is eaten by the bears and other mammals. A growing danger to existing wax palm forests is the growing interest in the tree as a biodiesel crop. This interest would not jeopardize the species itself, of course, but monoculture plantation forests such as those in which the oil palm is grown are less hospitable to the habitats of other species that develop around the naturally occurring monocultures of the Andean wax palm forests.
In 2020, the speckled bear was classified as vulnerable by the International Union for the Conservation of Nature (IUCN). This was due in part to climate change. The population of speckled bears has also decreased because of the construction of roadways and the destruction of forests for illegal coca and opium crops. Hunting is another threat. Locals hunt speckled bears for subsistence and to protect livestock. They also sell the bears' parts in the wildlife trade. For example, their gall bladders are used to make traditional medicine and can be sold for a high price.
Tapir Species
Four species of tapirs live in South America, three of which are large and native to rainforests. The fourth, the woolly or mountain tapir (Tapirus pinchaque), is the smallest and the only one to live in the Andean montane forests. About 6 feet (2 meters) long and 3 feet (1 meter) tall at the shoulder, tapirs are built stoutly and weigh as much as 500 pounds (227 kilograms). They have small tails and the long, flexible proboscises characteristic of their genus. Herbivores, they feed on ferns, umbrella plants, grasses, and pineapples.
The wax palm depends on them to disperse its seeds. Though mountain tapirs are not the only animals to feed on wax palm seeds, their digestive system is fairly inefficient, and they tend to defecate near bodies of water—a combination that makes them very adept at germinating in their dung the seeds of plants they have eaten. The wax palm and the highland lupine both decline dramatically when mountain tapir populations are reduced.
Bibliography
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