Central American montane forests
Introduction Cerro Verde, Guatemala. (Photograph by Steve Cornelius) This montane forest ecoregion (Central American montane forests) is made up of forest patches occurring in an island-like mosaics on the isolated tops and slopes of the highest mountains of Central America, from southern Mexico into northern Nicaragua. At such altitudes, the tropical climate gives way to a more temperate-like climate with fairly high precipitation.
This region provides for such animals as the endangered, endemic horned guan (Oreophasis derbianus). Much of the higher elevations remain relatively intact and are declared protected; however, there is little management or enforcement. Lower elevations have been altered by subsistence farming.
Location and General Description
The montane ecoregion of northern Central America exists as more than 40 relatively small habitat islands extending from southern Mexico to the southeast through Guatemala then into El Salvador and Honduras. The generally widely scattered mountains rise out of a matrix that is otherwise dominated by pine-oak forest and make up only about 10 percent of the total area. They range in size from a single massif of 2,000 km2 on the border between Mexico and Guatemala to small isolated mountains of less than 1 km2 in southern Honduras and western El Salvador. Maximum elevations of these habitat islands vary in elevation from less than 1,500 meters (m) to over 4,000 m.
These mountains are derived from different geological sources and are of vastly different ages. The more interior mountains of the group are mainly from early Paleozoic sedimentary and metamorphic rock including schists, gneisses, marbles and serpentines. Contrasting these is the ring of mountains along the Pacific Rim, which are of volcanic origin dating back to the late Pliocene. These newly formed volcanoes (six are still active) exist as striking cinder cones and world class scenic views such as that of Lake Atitlan in Guatemala.
Precipitation on these mountains is typically heavy with 2000 to 4000 millimeters (mm) falling annually and most of them are subjected to heavy cloud cover. The taller mountains experience regular light frosts at night between December and March.
The vegetation of the Central American montane ecoregion is a spectacular mix of northern and southern elements combined with high endemism, which reaches up to 70 percent in the larger habitat islands according to Dix. For example, these mountains are essentially the southern limits for genera of conifers such as Abies, Juniperus, Cupressus and Taxus, which tend to grow on the wetter, north-facing slopes near the tops of the higher mountains. These conifers form stands of large tall trees that are interspaced with more classical broadleafed evergreen forests that are dominated by oaks (Quercus). Mixed with these genera of northern origin are genera such as Persia spp. (Lauraceae), which are also associated with southern tropical habitats.
The eclectic mixture of stands of majestic conifers intermixed with tropical broadleafed cloud forest, both festooned with epiphytes, particularly bromeliads and orchids, makes these cloud forests unique in the world. These isolated mountain tops support both high levels of biodiversity and endemism, particularly among plants, but also birds. The horned guan (Oreophasis derbianus), for example, is an endangered and extremely local endemic bird species of these highland forests. Another spectacular avian resident is the subspecies of the resplendent quetzal (Pharomacrus mocinno mocinno). Also outstanding is the high number of conifer species, 13, virtually all of which terminate their southern extensions in this ecoregion and the surrounding pine-oak forest. The diversity and endemism is further increased in some massifs, such as Sierra de las Minas, where mineral outcroppings of marble support unique associations of epiphyte-laden oak forests with endemic agaves. The highlands of the Bocay River watershed contains Nicaragua's principle limestone formations.
As with other mountain ranges in tropical America, migration is an important ecological process. This ecoregion is characterized by both local altitudinal migrations, by birds and butterflies, and inter-continental migrations between Central America and North America. More than 20 species of birds that breed in North America spend their winters in Central American montane forest habitats.
Most of the higher elevations of the Central American mountains have been declared as protected areas though enforcement, or even infrastructure, is missing in most cases. Honduras, for example, has declared that all land over 1,800 meters is to be protected, but only 10 of at least 32 declared areas have been mapped or have conservation-related infrastructure. The situation in El Salvador is similar with very few areas actively protected. All protected areas in both these countries are small and unlikely to conserve their biodiversity if they are not expanded significantly. In Guatemala, the largest block of intact habitat is Sierra de las Minas, about 200,000 hectares (ha) – probably the only protected area in the ecoregion that has the potential for maintaining its full complement of biodiversity and ecological processes. Sierra de las Minas is also a biosphere reserve that is being consolidated by the country's leading non-governmental conservation organization, Defensores de la Naturaleza. Beyond this reserve, the government maintains the small Quetzal Biotope and the indigenous communities situated around the Pacific Rim volcanoes adjacent to Lake Atitlan have maintained small community reserves on these mountains.
Types and Severity of Threats
The intactness of this ecoregion varies as a function of elevation. The upper reaches of the mountains are typically too cool, wet and/or rugged to be hospitable to human activities and are therefore still largely intact. However, even those natural barriers to human intervention are giving way to the pressures of development as the area's primarily indigenous population outgrows its traditional agricultural base of corn cultivation in the surrounding pine-oak habitat and is forced to expand into areas that are ultimately unsustainable. The lower slopes of the montane ecoregion have already been heavily modified for cash crops, coffee and beef, and subsistence agriculture, particularly corn, and beans, as well as for fuelwood. The increasing loss of the lower slopes of these mountains threatens the faunal stability overall because it is exacerbating their already small size and further isolating them from sub-populations on other mountains.
Justification of Ecoregion Delineation
The delineation’s for the Central American montane forests were derived from a variety of national and international surveys. In Honduras the linework follows Holdridge and lumps the following life zones: lower montane wet forest, lower montane moist forest, and montane forest. In Guatemala the ecoregion follows the highest peaks of the central range, and lines are derived from the Instituto Geográfico Nacional atlas to include the following dense forest classification at higher elevations. Coverage in El Salvador was based on information from Arnoldo Guzmán’s map. The linework for the few small outliers in Nicaragua were derived from Sutton and national inventories. Finally, border areas were fused by expert opinion and estimates of historic ranges.
Additional information on this ecoregion
- For a shorter summary of this entry, see the WWF WildWorld profile of this ecoregion.
- To see the species that live in this ecoregion, including images and threat levels, see the WWF Wildfinder description of this ecoregion.
- World Wildlife Fund Homepage
- Holdridge, L.R. 1962. Mapa ecológico de Honduras. Map 1:1,000,000. OAS, Washington, D.C., USA.
- Cardenal Sevilla, L. 1994. Informe de País Nicaragua: Diversidad y Prioridades. A. Vega, editor. Corredores Conservacionistas en la Región Centroamericana: Memorias de una Conferencia Regional auspiciada por el Proyecto Paseo Pantera. Tropical Research and Development, Inc. Florida.
- Dix, M. A. 1997. Sierra de las Minas Region and Biosphere Reserve, Guatemala. In WWF and IUCN, Centres of plant diversity. A guide and strategy for their conservation. 283170197X/?tag=encycofearth-20 ISBN: 10 283170197X.
- Holdridge, L.R. 1962. Mapa ecológico de Honduras. Map 1:1,000,000. OAS, Washington, D.C., USA.
- Instituto Geográfico Nacional. 1972. Atlas nacional de Guatemala. Ministerio de Comunicaciones y Obras P’’ublicas. Guatemala City, Guatemala.
- Instituto Geográfico Nacional "Ingeniero Pablo Arnoldo Guzmán". 1987. Mapa básico de la República de El Salvador. San Salvador, El Salvador.
- Inventario Nacional de Recursos Fisicos. 1966. Nicaragua: vegetation. U.S. Army Corps of Engineers, AID/RIC GIPR No. 6, Washington, DC, USA.
- Instituto Nicaraguense de Recursos Naturales y del Ambiente (IRENA). 1992. Ordenamiento Ambiental del Territorio plan de accion forestal. IRENA, Managua, Nicaragua.
- Land H. C. 1970. Birds of Guatemala. Wynnewood, PA: Livingston. ISBN: 0915180103
- Reyes Chirinos, J. and G.A. Cruz. 1994. El Sistema Nacional de Areas Protegidas de Honduras. In A. Vega, editor, Corredores Conservacionistas en la Región Centroamericana: Memorias de una Conferencia Regional auspiciada por el Proyecto Paseo Pantera. Tropical Research and Development, Inc. Florida.
- Rich, P. V., and T. H. Rich. 1983. The Central American Dispersal Route: Biotic History and Paleogeography. In D.H. Janzen, editor, Costa Rican Natural History. University of Chicago Press, Chicago. ISBN: 0226393348
- Standley, P. C., J. A. Steyermark, and L. O. Williams. 1946-1977. Flora of Guatemala Fieldiana, Botany 24.
- Sutton, S.Y. 1988. Nicaragua. Pages 301-303 in D.G. Campbell, and H.D. Hammond, editors, Floristic inventory of tropical countries. New York Botanical Garden, Bronx, New York, USA. ISBN: 0893273333
- Villar Anleu, L. 1994. Informe de Pais Guatemala: Perfil General. Pages 193-221 in A. Vega, editor, Conservation Corridors in the Central American Region: Proceedings of a Regional Conference sponsored by the Paseo Pantera Project. Gainesville, FL: Tropical Research and Development Inc. 193-221.
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