DIVERSITY & ENDEMISM
The concentration of a wide variety of ecosystems in a relatively small area have led to very high levels of endemism in this hotspot.
There are an estimated 11,000 vascular plant species found in the Tumbes-Chocó-Magdalena hotspot, about 2,750 (25 percent) of which are endemic. Of these, an astonishing 5,000 are found in the Colombian Chocó, an area thought to be the most floristically diverse area in the Neotropics. Overall, endemism is quite high in this hotspot because of extensive speciation among several groups of plants, most notably the epiphytes, suggesting that the region was the location of plant refugia during Pleistocene glaciations. There are no endemic families in this hotspot, but the endemic genera include Otoba, Trianaeopiper, Schlegelia, and Cremosperma.
The northern parts of the hotspot in Ecuador and the Colombian Chocó are characterized by extremely wet or pluvial forests that receive eight meters of annual rainfall and have a diversity per hectare of as many as 300 tree species. Because of the abundant rainfall, species that are characteristically found in the montane cloud forests of the Andes can extend their range to the coast in this region. These species include representatives from the genera Podocarpus, Talauma, Hedyosmum, Meliosma, Brunellia, Panopsis, and Ilex.
The dry forests of southwestern Ecuador and northern Peru are dominated by large, emergent trees of the family Bombacaceae, including the ceiba (Ceiba trichistandra). These forests support high levels of endemism and are extremely threatened. The diversity of habitat types in the dry forest region includes scrub and desert, deciduous tropical thorn-scrub forest, deciduous ceiba forest, semi-evergreen lowland and premontane tall forest, and intermontane scrub.
The Galápagos Islands are home to nearly 700 species of vascular plants, of which about a quarter are endemic, including six endemic genera of flowering plants.
The forests of the Tumbes-Chocó-Magdalena hotspot are globally important for bird endemism, holding nearly 900 total species, around 110 of which are found nowhere else in the world. This includes 14 endemic bird genera, 10 of which are represented by a single species.
Of the hotspot's six Endemic Bird Areas (EBAs), defined by BirdLife International, the Tumbesian region EBA and the Chocó EBA are considered two of the most important and critically threatened in the world. The Tumbesian Region EBA, with 17 threatened bird species confined entirely to it, such as the white-winged guan (Penelope albipennis, CR) and the Peruvian plantcutter (Phytotoma raimondii, EN), is considered one of the three EBAs most critically in need of conservation action. The Chocó EBA has a total of 51 species confined to it, a total second only to the Atlantic Forest Lowlands EBA. The Galápagos Islands form an EBA in their own right, with 22 endemic terrestrial species including the 12 species of Darwin's finches so important to Darwin’s Theory of Evolution.
Among the distinctive bird species in the hotspot is the aforementioned white-winged guan (Penelope albipennis, CR), which is found only in the dry forests at the southern extreme of the hotspot. The white-winged guan was rediscovered in 1977 after not having been seen for more than a century; today, fewer than 200 individuals are thought to exist in the wild. In 1991, a new bird species was discovered in the Colombian Chocó; it was described in 1996 as the Chocó vireo (Vireo masteri, EN) through the auction of its scientific name to Dr Bernard Master, raising $70,000 for the conservation of its threatened rainforest habitat. Other flagship species include the bizarre long-wattled umbrella bird (Cephalopterus penduliger, VU) and the blue-black grass quit (Volatinia jacarina), the latter being the common ancestor of the Galápagos finches.
There are more than 285 mammal species in the hotspot; 11 of these are endemic. Among mammals, primates are probably the best known. Flagships include three species of spider monkey of the genus Ateles (A. fusciceps, A. geoffroyi, and A. hybridus, CR) and three species of bare-faced tamarins of the genus Saguinus: the cotton-top tamarin or mono tití blanco (S. oedipus, EN), the rufous-naped or Panamanian tamarin or bichichi (S. geoffroyi), and the white-footed tamarin or tití del Chocó (S. leucopus, VU).
Half of the region's endemic species live on the Galápagos, including the rice rats of the genus Nesoryzomys, although the most recognizable mammal species in the archipelago is the Galápagos Islands fur seal (Arctocephalus galapagoensis, VU), the smallest of the pinnipeds.
As is the case with plants, the hotspot also holds a number of more widespread mammal species, including the jaguar (Panthera onca), Baird's tapir (Tapirus bairdii, EN), the nine-banded armadillo (Dasypus novemcinctus), and the olingo (Bassaricyon gabbii).
It is estimated that there are more than 320 reptile species in the hotspot, of which nearly 100 are endemic (including more than 20 species on the Galápagos). The region's most diverse reptile families are the Colubridae, the world's largest snake family, with 122 species present (16 endemic); there are also more than 40 species of the lizard genus Anolis in the hotspot (family Polychrotidae), three-quarters of which are endemic. Of the region’s five endemic genera, the best known are the marine iguana (Amblyrhynchus cristatus, VU) and the two threatened species of land iguana endemic to the Galápagos, the Santa Fe land iguana (Conolophus pallidus, VU) and the Galápagos land iguana (Conolophus subcristatus, VU).
Other reptile species present include Dahl's toadhead turtle (Phrynops dahli, CR) and Dunn's mud turtle (Kinosternon dunni, VU), both endemic, and the American crocodile (Crocodylus acutus, VU), which, while not endemic, is threatened by hunting.
Amphibian diversity is even more impressive than reptile diversity in this hotspot, with more than 200 species, around 30 of which are endemic. New species are being discovered faster than they can be described, demonstrated by the shelves of specimens waiting to be described at the National Herpetological Collection in Bogotá, Colombia.
Some of the best-known amphibian species in the region are the poison dart frogs of the family Dendrobatidae. These beautiful, brightly colored little animals secrete toxic alkaloids through their skin, their bright aposematic coloration serving to warn predators that they are off limits. The bright yellow golden poison frog (Phyllobates terribilis, EN), which is found only in the Saija River Basin in the southern Chocó, is one of the three most poisonous vertebrates in the world. Its toxicity is such that the local Emberá Indians poison their blowgun darts simply by rubbing them along the backs of these little frogs. However, many of the hotspot's endemic amphibians are limited to habitats of only a few square kilometers, making them particularly vulnerable. Indeed, several taxa have already disappeared in Ecuador in recent years.
There are no native amphibians on the Galápagos, although Fowler's snouted tree frog (Scinax quinquefasciata) has become established on Santa Cruz.
The coastal watersheds of northwestern South America have relatively sparse fish faunas compared to the great watersheds on the Atlantic side of the continent. The hotspot has about 250 species of fish (nearly half of which are endemic) in 54 families, with seven endemic genera; endemism is centered around the Magdalena and Atrata valleys. There is a single endemic species (Ogilbia galapagosensis) on the Galápagos.