DIVERSITY & ENDEMISM
The Tropical Andes is home to an estimated 30,000-35,000 species of vascular plants, accounting for about 10 percent of all the world's species and far surpassing the diversity of any other hotspot. It is also the world leader in plant endemism, with an estimated 50 percent (and perhaps 60 percent or more) of these species found nowhere else on Earth. This means that nearly seven percent of the world's vascular plants are endemic to the 0.8 percent of the earth’s land area represented by this hotspot. These numbers are only conservative estimates and are likely to be greater; between 1999 and 2003, nearly 450 new plant species were described from the Ecuadorian portion of the hotspot alone. There are also approximately 330 endemic genera, and a single endemic family, the Columelliaceae.
Describing the diversity and endemism of the world's richest flora cannot be accomplished in a single paragraph. However, a few important trends should be noted. The forests of the Tropical Andes are floristically different from their lowland counterparts in that they contain significant representation of Laurasian plant families and genera not found in the lowlands, as well as Gondwana-derived taxa. In general, diversity decreases with altitude within this hotspot, and endemism increases. However, the puna and parámo grasslands that extend from the cloud forests to the snow line are still very diverse, harboring as many as 800 species, many of these local endemics.
The region is home to a number of unusual plant species, including a type of high Andean bromelilad (Puya raimondii) that takes as much as a century to reach maturity, and an endemic palm species (Parajubaea torallyi, EN), that grows at the highest altitude of any palm on Earth (3,400 meters). The hotspot is also the center of origin for some of world's most important crops, including tobacco and potatoes, as well as the cinchona plant, which is the source of quinine. However, agriculture and timber production have imperiled significant portions of this hotspot; the magnificent Podocarpus-dominated cloud forests are largely gone.
The Tropical Andes harbor more than 1,700 bird species, nearly 600 of which are endemic, a level of endemism that is unequaled in the world. In addition, the region has 66 endemic bird genera, and includes all or part of 21 different Endemic Bird Areas, as defined by BirdLife International. To put these numbers in perspective, consider the hummingbirds (Trochilidae). The eastern continental United States is the summer breeding ground for one species, but in the Nariño department in southern Colombia (one quarter the size of New York state), there are over 100 resident hummingbird species.
At present, nearly 160 bird species in the Tropical Andes are threatened, and at least one species, the Colombian grebe (Podiceps andinus), has gone extinct in the last century. Highly threatened birds include blue-billed curassow (Crax alberti, CR), Niceforo's wren (Thryothorus nicefori, CR), Fuertes's parrot (Hapalopsittaca fuertesi, CR), black-breasted puffleg (Eriocnemis nigrivestis, CR), Kalinowski's tinamou (Nothoprocta kalinowskii, CR), and royal cinclodes (Cinclodes aricomae, CR). The yellow-eared parrot (Ognorhynchus icterotis, CR), reportedly common across Colombia and Ecuador at the turn of the 20th century, survives in two small populations in the Colombian Andes. Here in the Quindío wax palm habitat (Ceroxylon quindiuense, VU), which is the species' obligate habitat, ProAves Foundation is working on conservation initiatives that are buying the yellow-eared parrot a chance for survival.
The region is home to the spectacular Andean condor (Vultur gryphus), one of the largest flying birds on Earth. Hunted nearly to extinction, the condor is now making a comeback through conservation and reintroduction programs. The hotspot also boasts the greatest diversity of hummingbirds in the world, including the world's largest, the giant hummingbird (Patagona gigas), and the marvelous spatuletail (Loddigesia mirabilis, EN), appropriately named for its long racquet-shaped tail.
There are nearly 570 mammal species in the Tropical Andes hotspot; about 75 of these are endemic and nearly 70 are threatened. The hotspot also has six endemic genera, each represented by only one species: Garlepp's mouse (Galenomys garleppi), the Andean rat (Lenoxus apicalis), little or mountain coati (Nasuella olivacea), puna mouse (Punomys lemminus), and fish-eating rat (Anotomys leander, EN), a species known only from the Andes of northern Ecuador and highly specialized for an aquatic existence.
The sixth endemic genus is one of the most important mammalain flagship species for the Tropical Andes, the yellow-tailed woolly monkey (Oreonax flavicauda, CR), which was believed to be extinct until it was rediscovered in 1974. It is the largest mammal endemic to Peru, and is only one of three primate genera in the Neotropics to be endemic to a single country. It is restricted to a small area of cloud forest in the northern Peruvian departments of Amazonas and San Martín. Other large mammals found in the area include the woolly or mountain tapir (Tapirus pinchaque, EN) and the spectacled bear (Tremarctos ornatus, VU), which is the only bear in South America and is endemic to this hotspot.
The vicuña (Vicugna vicugna) – which along with the domesticated llama (Lama glama), the alpaca (Lama pacos), and the wild guanaco (Lama guanicoe) is one of four distinctive camel species found in the Tropical Andes – represents an important conservation success story for this hotspot. Considered to have one of the finest wools in the world, the vicuña was driven to the brink of extinction, until a sustainable-use program implemented in the 1970s led to its dramatic recovery.
There are more than 600 reptile species identified in the Tropical Andes hotspot (more than 270 of which are endemic) and three endemic genera, a level of endemism unequaled in the world for this class. The region's reptiles include the primitive tree boa (Corallus enydris), an arboreal snake which has a pelvis and vestigal hind limbs, and the Magdalena river turtle (Podocnemis lewyana, EN), found in the Rio Magdalena River basin.
The Andes is the most important region in the world for amphibians, with around 980 species and more than 670 endemics. Eight amphibian genera are endemic to the Andes. The most specious of these is the frog genus Telmatobius, with about 45 species. Many other non-endemic genera are highly speciose; the frog genus Eleutherodactylus has more than 330 species, of which more than 250 are restricted to the hotspot.
The best-known amphibians from the Tropical Andes are the brightly colored poison dart frogs from the family Dendrobatidae. Some of these frogs are among the most poisonous organisms on Earth; others, like Epipedobates tricolor, which produces a compound more powerful than that of morphine, hold promise as the source of new medicines.
Unfortunately, the amphibian fauna in the Tropical Andes is also among the most threatened; around 450 species are listed on the 2004 IUCN Red List as threatened, and more than 360 of these are endemic to the hotspot. Although habitat loss is playing a major role in driving many of these extinctions, disease, particularly due to the pathogenic chytrid fungus B. dendrobatidis has had devastating impacts on amphibian populations in this part of the world. The stream-dwelling harlequin frogs of the genus Atelopus have been especially affected - of the 60-odd species of Atelopus occurring in this hotspot, 56 are considered Critically Endangered.
There are more than 375 documented species of freshwater fishes in the hotspot, and it is likely that many more will be found along the Amazonian flanks of the mountains. Of these, more than 130 are endemic, including the members of the genus Orestias, which is represented by more than 40 unique species in Lake Titicaca and nearby drainages. All but a few of the 90 species of naked sucker-mouth catfishes in the family Astroblepidae are also endemic to the region