Location and General Description
The Central American pine-oak forest ecoregion incorporates the central Chiapas state of Mexico, southern Guatemala, most of Honduras and El Salvador, and small areas of west central Nicaragua. This ecoregion encompasses the Sierra Madre de Chiapas with mountain ranges that run parallel to the Pacific Coast (Stattersfield et al. 1998), and various mountain ranges with complex topography. The area, which delineates what geologists consider the oldest geologic nucleus of Central America (Villar Anleu 1994), consists of mountains that run from the Isthmus of Tehuantepec, in southern Mexico, to northern Nicaragua. They consist principally of old (Paleozoic) metamorphic and sedimentary rocks and sediments, granitic formations and ultramaphic rocks, interspersed with smaller areas of highly-eroded formations originating from volcanic activity of the Terciary period (Villar Anleu 1994).
Precipitation in the area varies from north to south, with some areas receiving less rain, and others, such as the Sierra de Chiapas, with an annual precipitation of 1,500 mm (Rzedowski 1994).
The ecoregion is dominated by a rich assemblage of pines, Pinus spp., and oaks, Quercus spp., and it marks the southern limit of boreal floristic influence in the New World. Pine-oak forests are found at altitudinal ranges that vary from 600 to 1,800 m above sea level (Harcourt & Sayer 1996). Mixed forests of pine and oak are found between conifer and broad-leaved forests. The dominant species of these mixed forests include Pinus spp., Quercus spp., Ostrya sp. and Alnus spp.
Common tree species in the Sierra Madre of Chiapas are Quercus acatenangensis, Pinus strobus and Pinus ayacahauite. While pines are found at higher elevations (Rzedowski 1994), there are various species of oaks found at lower altitudes; they include Quercus corrugata, Q. skinneri, Q. oleoides, Q. candicans, Q. acatenangensi, Q. brachystachys, Q. peduncularis, Q. polymorpha, and Q. conspersa. The Sierra de Chiapas is considered an area of distribution of Mexican pines; some of these species include Pinus chiapensis, P. patula subsp. tecunumanii, P. ayacahuite, and P. maximinoi (Styles 1993). Lichens and moss are also common in this region; vascular epiphytes are scarce, probably due to pine and oak tree toxicity (Rzedowsky 1994).
At higher elevations in Guatemala, the conifer forests include Pinus spp., Abies guatemalensis, Cupressus lusitanica, and Taxodium mucronatum. A large portion of the pine-oak forests in the central and western Honduras contains predominant species of Pinus oocarpa and Quercus spp. at lower elevations, and Pinus pseudostrobus and Liquidambar styraciflua at higher elevations. In the Olancho area of Honduras, the trees reach exceptionally large stature, creating an especially regal forest. Pine forests in Nueva Segovia in Nicaragua occur at 400-700 m; these forests include Pinus oocarpa, P. maximinoi and P. patula tecunumanii. The pine-oak forests in El Salvador have almost entirely been cleared. Some of the remaining forests include Quercus spp. and Pinus oocarpa with other species like Cedrella mexicana, Clethra vulcanicola, Permymenium spp. and Nectandra sinuata (Harcourt & Sayer 1996).
The highland massif of northern Central America contains scattered emerging islands of cloud forest. Some conifers found in cloud forests at high elevations include Abies guatemalensis, Cupressus lusitanica, Pinus ayacahuite, P. maximinoi, P. patula tecunumaii, P. pseudostrobus and Podocarpus oleifolius.
The most outstanding characteristic of the pine-oak forests is the richness of the genus Pinus. These species are wedged between the predominantly broad-leafed evergreen cloud forests of higher, wetter elevations, and the lowland tropical wet forests, which are made up almost exclusively of broad-leafed species. Some endemic flora in the Sierra of Chiapas includes Alfaroa aff. mexicana, Ficus crassicuscula, Anthurium ovandensis, Zamia soconuscensis, Ceratozamia matudai and Quercus ovandensis. (Gómez-Pompa & Dirzo 1995).
This ecoregion is rich in fauna. There are approximately 141-160 mammals present in the Sierra de Chiapas (Fa & Morales 1993). Some of the restricted range mammals in this and other ecoregions of Mesoamerica include the cacomistle (Bassariscus sumichrasti), bats (Balantiopteryx io, Molossus aztecus, Macrotus waterhousii, Glossophaga leachii, Hylonycteris underwoodi, Carollia subrufa, Dermanura azteca, Dermanura tolteca and Bauerus dubiaquercus), Mexican mouse opposum, (Marmosa mexicana), rodents (Liomys pictus, Microtus guatemalensis, Ototylomys phyllotis, Peromyscus aztecus, Reithrodontomys sumichrasti, and Scotinomys teguina) (Arita Watanabe).
Among some of the endangered mammals found in this ecoregion are the jaguar (Panthera onca), puma (Felis concolor), ocelot (Leopardus pardalis), tapir (Tapirus bairdii), greater grison (Galictis vittata), tayra (Eira barbara), Central American spider monkey (Ateles geoffroyi), and mantled howler monkey (Alouatta palliata). Some of the herpetofauna include Masticophis mentovarius, Bolitoglossa celaque, Plectrohyla psiloderma. According to Flores-Villela (1993), there are approximately 16 species of endemic amphibians and 24 species of endemic reptiles in the Sierra de Chiapas.
The highlands of northern Central America are considered an Endemic Bird Area, and these forests are the wintering grounds for many migratory warblers, Parulidae, from the nearctic. Among these are the threatened Golden-cheeked warbler (Dendroica chrysoparia) and Azure-rumped tanager (Tangara cabanisi) (Wege and Long 1995). Restricted range birds in this ecoregion include the Santa Barbara screech-owl (Otus barbarus), belted flycatcher (Xenotriccus callizonus), pink-heade warbler (Ergaticus versicolor), and black-capped siskin (Carduelis atriceps) classified as near threatened. Other restricted birds include the ocellate quail (Cyrtonyx ocellatus), fulvus owl (Strix fulvescens), green-throated mountain-gem (Lampornis sybillae), wine-throated hummingbird (Atthis ellioti), blue-throated motmot (Aspatha gularis), black-capped swallow (Notiochelidon pileata), rufous-browed wren (Troglodytes rufociliatus), blue-and-white mockingbird (Melanotis hypoleucus), rufous-collared robin (Turdus rufitorques), bar-winged oriole (Icterus maculialatus), and bushy-crested jay (Cyanocorax melanocyaneus) (Stattersfield et al. 1998).
The status of the pine-oak forests of Central America varies by country. The human populations of Guatemala and El Salvador are concentrated primarily within this ecoregion, and they continue to exert strong negative impacts on the remaining fragmented. In contrast, considerable intact habitat remains in Honduras, although it is still being subjected to a wide array of expanding human impacts, including extensive logging. Pine-oak forests have been extensively cleared for agricultural purposes, including cattle, or degraded through logging, or cutting for firewood (Dinerstein et al. 1995, Cardenal Sevilla 1994).
The ecoregion includes several protected areas. In Mexico, El Triunfo Biosphere (IUCN category VI) has an area of 1,192 km2 and Lagunas de Montebello National Park has 60 km2. In Nicaragua, Cordillera Dipilto y Jalapa Nature Reserve (IUCN category IV) with an area of 412 km2, and Cerro Tisey Nature Reserve (IUCN category IV) has 64 km2. In Honduras, Celaque National Park (IUCN category II) with an area of 270 km2, and Pico Pijol National Park (IUCN category II) has an area of 114 km2. In Guatemala Sierra de las Minas Region and Biosphere Reserve (IUCN category VI) of 1,430 km2, contains about 13 species of Pinus. In El Salvador, Montecristo National Park (IUCN category IV), with an area of 52 km2, is the last remaining forest in El Salvador.
Types and Severity of Threats
Human populations of Central America continue to grow at a high rate, and are expected to double within the next thirty years. Thus, the threats against the ecoregion can only be expected to increase, at least for the foreseeable future. As demands for wood increase, and alternative supplies decrease, the pressure on remaining forest in Honduras is similarly increasing at an exponential rate. The pine-oak forests of Central America are poorly represented in protected areas, and no large tracts of pine-oak forest are protected anywhere. A few protected areas in the ecoregion, such as Sierra de las Minas Biosphere Reserve in Guatemala and Cusuco and Agalto National Parks in Honduras, are primarily designed to protect cloud forest, but include small amounts of pine-oak forest in their core zones. There is an urgent need to expand these and other cloud forest protected areas to include adjacent down-slope habitats, such as the pine-oak forests. This will not only apply protection to these under-represented habitats, but will help to insure that elevational profiles are maintained for altitudinal migrants, such as the Resplendent Quetzal (Pharomacrus mocinno), which move into pine-oak forests during the non-breeding season. Furthermore, there should be a concerted effort to expand and upgrade the protection of the pine-oak forests in eastern Honduras where the most intact habitat remains.
Justification of Ecoregion Delineation
Delineation’s for these pine-oak forest were based on regional maps, and on elevational data where historic ranges were unknown. In Mexico, linework was derived from INEGI maps (1996) with reference to Rzedowski (1978) and were reviewed and modified in expert workshops (CONBIO 1996 and 1997). Linework for Guatemala were derived from the national atlas (Instituto Geográfico Nacional, 1972) and from Junio (1982) and modified according to expert opinion. For El Salvador, the Instituto Geográfico Nacional "Ingeniero Pablo Arnoldo Guzmán" map was utilized (1987) for major linework, and blended with border regions. For Nicaragua, Inventario Nacional de Recursos Fisicos (1966) and Instituto Nicaraguense de Recursos Naturales y del Ambiente (1992) maps were used to combine pine-oak elements. Holdridge (1962) was the primary reference for Honduras, and the linework follows lumping of premontane wet forest and premontane moist forest life zones.
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Instituto Nicaraguense de Recursos Naturales y del Ambiente (IRENA). 1992. Ordenamiento Ambiental del Territorio plan de accion forestal. IRENA, Managua, Nicaragua.
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Villar Anleu, L. 1994. Informe de País Guatemala: Perfil General. In Vega, A. Corredores Conservacionistas en la Región Centroamericana: Memorias de una Conferencia Regional auspiciada por el Proyecto Paseo Pantera. Tropical Research and Development, Inc. Florida.
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Prepared by: George Powell, Sue Palminteri, Claudia Locklin, and Jan Schipper
Reviewed by: In process