Tumbes-Chocó-Magdalena

José Vicente Rodríguez-Mahecha²⁵, Paul Salaman²⁵, Peter Jørgensen²⁶, Trisha Consiglio²⁶, Luis Suárez²⁷, Fabio Arjona²⁵ and Robert Bensted-Smith²⁷

The Tumbes-Chocó-Magdalena Hotspot was previously referred to as the Chocó-Darién-Western Ecuador Hotspot in Mittermeier et al. (1999). It has now changed its name and expanded its boundaries to include several new areas, most notably the Magdalena Valley in Colombia. As we now define this hotspot, it originally covered 274 597 km² in the northwestern corner of South America. It begins east of the Panama Canal in the wet and moist forests of Panama's Darién Province, extends south through the Chocó region of western Colombia, and then on into the moist forests of northwestern Ecuador, where it is bounded by the Pacific Ocean to the west and the western slope of the Andes to the east. It then also extends still further south to include the dry forests of western Ecuador and those in Tumbes, Piura, and La Libertad departments in the extreme northwestern corner of Peru, south as far as Huacho. In northern Colombia, the hotspot also follows the forests of the Chocó as they go east around the northern Andean termini and into the Magdalena Valley. In addition to the mainland portion of the hotspot, we also include here the island of Malpelo (8 km²), located around 500 km off the coast of Buenaventura, Colombia, and the Galápagos Islands (7 882 km²), lying some 960 km west of Ecuador in the Pacific Ocean and including 13 large islands and six smaller islands lying right on the equator. Although these islands are volcanic in origin, they do have some floristic affinities with the mainland, and therefore are included here with the geographically nearest hotspot.

This hotspot is characterized by a great variety of habitats ranging from extensive mangrove areas, beaches, rocky shorelines, and coastal wilderness and dry forests, to the world's wettest rainforests. The dry forest region of western Ecuador and Tumbes and Piura in Peru is especially diverse, with habitats ranging from arid scrub and desert through deciduous tropical thornscrub forest and deciduous Ceiba trichistandra forest, to semievergreen C. pentandra forest, semievergreen lowland and premontane tall forest, to deciduous to semievergreen intermontane scrub. Punctuating the otherwise flat coastal plain, this hotspot also contains numerous smaller mountain systems, including the Serranía del Sapo, Serranía de los Saltos, and Serranía del Baudo, which run parallel to the coast in extreme western Colombia; the Cordillera de San Blas and Serranía del Darién in southeastern Panama; the Serranía de Abibe and Serranía de San Lucas in northern Colombia; the Cordillera de la Costa in Ecuador; and the Cerros de Amotape in Peru, all of which represent “islands” of endemism that add to the wide spectrum of biodiversity in this top-priority ecosystem.

Broadly speaking, the Tumbes-Chocó-Magdalena Hotspot can be divided into two major phytogeographic regions: the wet and moist forest Chocó and Darién biogeographic zones in the north and the Ecuadorian and Peruvian dry forest zone in the south, with a number of subtle geographic and biological barriers within these. The variety of ecosystem types in such a limited geographic area has given rise to high levels of diversity and endemism, and overall plant diversity in the hotspot is estimated at 11 000 species; plant endemism is estimated at 25%, which gives a figure of 2 750 endemic species of vascular plants for this hotspot. Plant diversity in the Colombian portion of the hotspot alone reaches an estimated 5 000 total species (G. Galeano, pers. comm.), and it is thought that the Colombian Chocó is likely to be the most floristically diverse site in the Neotropics. Based on an assessment of the Missouri Botanical Garden's TROPICOS Database, it has been estimated that we need five times the number of plant collections that have been made to date to be reasonably certain of the region's plant diversity. The flora of the Galápagos Islands is represented by 699 species of vascular plants, of which at least 177 species are endemic (25.3%), and there are six endemic genera of flowering plants (Jørgensen and León-Yánez 1999; Valencia et al. 2000).

In terms of vertebrate diversity and endemism, the Tumbes-Chocó-Magdalena Hotspot is impressive. Bird diversity in the mainland portion of the hotspot is 892 regularly occurring species, with 112 endemics. There are also 13 endemic bird genera, 10 of which are monotypic and, with the exception of the spiny-faced antshrike (Xenornis setifrons, VU), all are represented by species considered not threatened by BirdLife International, which is surprising. BirdLife International also considers this region to be a very high priority, and recognizes six Endemic Bird Areas (EBAs) in the hotspot as here defined, including the Nechi Lowlands, the Darién Lowlands, the Darién Highlands, the Tumbesian Region, and the Chocó. The Tumbesian Region EBA, with 17 threatened bird species confined entirely to this EBA (such as the white-winged guan, Penelope albipennis, and the Peruvian plantcutter, Phytotoma raimondii), 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 (Stattersfield et al. 1998). 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. 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.

Mammal diversity and endemism are also high in this hotspot, with 283 species, of which 10 are endemic, five of them on the Galápagos. The rice rats of the genus Nesoryzomys are confined entirely to the Galápagos Islands. The location of this hotspot at the transition zone between Central and South America results in the occurrence of some largely Central American mammal species (for instance, pocket gophers of the family Geomyidae) that can not be found elsewhere in the South American continent. Also among the mammals of this hotspot are a number of important primate flagships, including 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). On the Galápagos Islands, the most recognizable flagship is the Galápagos Islands fur seal (Arctocephalus galapagoensis, VU), the smallest of the pinnipeds, with an adult length of about 1.5 m.

Reptile diversity is quite high in this hotspot, with an estimated 325 species, of which 98 are endemic (including 21 species on the Galápagos). The lizard genus Anolis is particularly well represented, with 42 species present, 30 of them endemic). There are also five endemic genera including Emmochliophis, for which the two species, E. fugleri and E. miops, are known only from a single male and a single female specimen from western Ecuador;Teuchocercus, with a single species, T. keyi, from Ecuador; and Trachyboa, represented by two species of snakes. The remaining two endemic genera are also among the hotspot's most remarkable flagship species, and both occur in the Galápagos: the marine iguana (Amblyrhynchus cristatus, VU) and the two threatened species of land iguana (Conolophus spp.).

Amphibian diversity is even more impressive, with 204 mainland species, of which 29 are endemic, including two species of caecilians (Caecilia antioquiaensis and C. tenuissima). There are no native amphibians on the Galápagos, although Fowler's snouted tree frog (Scinax quinquefasciata) has become established on Santa Cruz. Among the amphibians, the poison arrow or poison dart frogs (Dendrobates spp.) of the family Dendrobatidae are important flagships. 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. One species, the golden poison frog (Phyllobates terribilis, EN), a bright yellow species found only in the Río Saija Basin in the southern portion of the Colombian Chocó, is among the three most poisonous vertebrates in the world, and its toxicity is such that the local Emberá Indians poison their blowgun darts simply by rubbing them along the backs of these little frogs. Unfortunately, many of the known amphibian endemics have very limited ranges such as isolated ridge tops only a few square kilometers in extent, making them particularly vulnerable to extinction.

The coastal watersheds of northwestern South America have rather sparse fish faunas compared to the great watersheds of the Atlantic versant, and the hotspot contains only 251 species in 54 families. Miocene fossils from the Magdalena Basin show that the fauna was richer in the past and that many characteristic elements of the Amazon/Orinoco fauna were present prior to uplift of the Andes. Isolation following uplift has contributed to a moderate level of endemism, with 115 endemic species and seven endemic genera, centered primarily in the Magdalena and Atrato basins. There is also a single endemic species (Ogilbia galapagosensis) on the Galápagos.

As a whole, it is estimated that natural vegetation remaining in more or less pristine condition in this hotspot is approximately 24% of the original extent, with much of what remains occurring in the Colombian Chocó and parts of the Darién. Current threats to the region are the same as in most other hotspots, and range from direct conversion of land for both large- and smallscale agriculture, such as banana and African oil palm, to climate change and elevated ultraviolet radiation impacting amphibians and perhaps other species as well. Many different kinds of infrastructure development (such as roads, dams, and canals) are also planned for this region, and colonization is on the rise in many areas. Finally, hunting continues to be an issue in some parts of the hotspot, especially for several of the larger bird and mammal species.

The degree of threat varies considerably from region to region. The Ecuadorian portion of this hotspot is under the gravest threat at present, with only about 2% of the original forest cover remaining. The situation in the Panamanian Darién is substantially better, with some 65% of original forest cover still remaining, while the Chocó region of Colombia, and especially the Department of Chocó, remains largely intact. Mangrove ecosystems are under threat throughout this hotspot due to overexploitation for timber and fuelwood, and because they are cleared to give way to shrimp aquaculture, an activity that has already destroyed many Ecuadorian mangroves. The Galápagos Islands are severely impacted by invasive alien species, and only three of the larger islands are considered unaltered by humans.

Portions of this hotspot, and especially the Chocó and western Ecuador, have been considered among the planet's highest priorities for conservation for more than twenty years (e.g., Gentry 1977, 1979). This has resulted in a wide range of conservation projects by national governments, multilateral and bilateral funding agencies, and international and national conservation organizations, which have led to the creation of a range of protected areas and many other conservation efforts of varying success. Presently, approximately 12.5% of the hotspot is considered protected; however, only 6.9% of the hotspot is conserved in IUCN categories I to IV. A large network of indigenous reserves and comunas (communal Black ancestral lands) exists throughout the hotspot, an example being that of several Awá Indigenous Reserves straddling the Colombia- Ecuador border. Although indigenous reserves do not necessarily protect the full range of biodiversity as well as a fully protected national park or biological reserve, they do have great significance for conservation and ensure more sustainable use of natural resources than Western forms of development. The Global Conservation Fund at Conservation International is currently supporting several initiatives in northwestern Ecuador, focused on protection of remaining intact lowland forests in and around the Cotacachi Cayapas Ecological Reserve and Awá Ethnic Reserve. Key interventions in this area include community-supported land acquisitions, purchase of logging concessions, community land titling, and development of community-based incentive agreements for conservation.

The Critical Ecosystem Partnership Fund (CEPF) has also made considerable investments in the Chocó-Manabí portion of this hotspot. Since this program began in January, 2002, some $3.3 million have been awarded to 24 different projects focused on field activities and strengthening local NGO capacity.

Elsewhere, other significant areas have been proposed for protection as well, including such biologically important zones as the Naya Corridor in the southcentral Colombian Chocó (Departments of Valle and Cauca), the protection of which would help conserve an altitudinal transect from the peaks of the western Andean cordillera to the sea, and represent perhaps the last, best chance to conserve a representative sample of the Chocoan forest ecosystems.

Last, but not least, the Galápagos have long been a focus of conservation activity and investment, and the vast majority of this unique archipelago is now recognized as both a World Heritage Site and a Biosphere Reserve.

In summary, the Tumbes-Chocó-Magdalena Hotspot presents several challenges and opportunities. Given the relatively intact nature of the Chocó and the Darién, there is a better possibility of setting aside large blocks of forest habitat than in most other hotspots. At the same time, in the Ecuadorian portion of this hotspot, in both the wet and moist forests and the dry forests, there exists the need for the same kind of immediate salvage-type operations required in some of the other highly degraded, endemic-rich hotspots like the lowland forests of the Philippines and the northeastern portion of Brazil's Atlantic Forest Region, which are also at or under 3% of their original extent. There is no doubt that the future of these Ecuadorian forests hangs in the balance, and that they must be placed at or near the top of any list of global biodiversity conservation priorities.

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