Rainbow over high Pacific facing slopes of the Talamancan
Range. Source: C. Michael Hogan
The Talamancan montane forests is an ecoregion situated along the mountainous spine of the Cordillera Talamanca within Costa Rica and Panama. These forests represent one of Central America’s most intact habitats.
This region provides habitat for considerable floral and faunal species diversity, many of which taxa are endemic. Over 30 percent of the ecoregion's flora, including over 10,000 vascular and 4000 non-vascular plant species, are endemic to this area, as are a number of fauna species. Nearly 75 percent of original forest cover remains intact, with forty percent protected by national and international parks.
However, the clearing of forest for crops and cattle pastures have begun to alter the unprotected habitat, as has timber harvesting. Because of the archipelago-like distribution of these montane patches along the Cordillera Central, beta-diversity is high between mountains and ranges, as well as along an elevational gradient.
Geography and general depiction
This ecoregion's combination of significant elevation variation, climatic gradients and central location along the land bridge between North and South America provides it with tremendous biological richness and endemism. Located in the highlands of Costa Rica and western Panama, the Talamanca Montane forests ecoregion occurs above 750 meters (m) and above 1500 m in some places on the Pacific slope, up to approximately 3000 m, where they grade into páramo grasslands.
The rainfall and temperature in this area of Central America is a direct result of the elevation and orientation north or south side of the mountain range. The average temperature and rainfall for this part of Costa Rica varies from 25°C and 2000 millimeters (mm) at the Caribbean Sea level to –8° C and >6000 mm at the highest peaks including Cerro Chirripo, the highest point in southern Central America at 3820 m. The high humidity and precipitation (which averages between 2500 and 6500 mm annually), steep slopes, and cool temperatures have limited agricultural and urban development, making these highland moist forests one of Central America's most intact ecosystems.
This southern portion of Central America is in a zone of tectonic plate convergence, where two small oceanic plates are being driven down below the Caribbean continental plate. These geologic movements resulted in tectonic instability, the uplifting of the Talamanca Range over 15 million years ago, and the fusion of South and North America 3.5 million years ago. These plate movements continue producing seismic and volcanic activity in the region to the present time; however, these mountains are not a result of volcanic activities, resulting in their status as the highest and widest non-volcanic mountains in Central America. This ecoregion was also shaped by ancient glaciation, which has left areas with cirque lakes and steep sided valleys of more than a 60° pitch in places. Within this ecoregion, these glacial remnants are the only signs of glaciation in Central America. The dominant soil type is poorly evolved inceptisols formed due to the continual leaching of minerals from the soils by the high influx of water.
The forest habitats of this ecoregion include Atlantic slope "aseasonal" rainforest, Pacific slope seasonally dry but mostly evergreen forest, and "perpetually dripping cloud forest" on the mountain tops, above approximately 1500 m. The high annual rainfall, wind-blown mist, and frequent presence of clouds, probably the most outstanding characteristic of these montane forests, produce a lush, dense forest with a broken canopy and high species diversity. Abundant epiphytes cover tree branches, and tree ferns are common. Dominant tree groups include the Lauraceae family, especially in the northern section of the ecoregion, and endemic oaks (Quercus spp.), especially in the south. The unique oak forest stands in this ecoregion are characterized by majestic, tall trees (up to 50 m tall), heavily dominated by two species: Quercus costaricensis and Q. copeyensis, while Magnolia, Drymis, and Weinmannia are also important tree elements. The understory is characterized by the presence of several species of dwarf bamboo (Chusquea). Higher peaks and ridges exposed to moisture-laden trade winds support an elfin, or dwarf forest characterized by thick mats of bryophytes covering short, dense gnarled trees.
The separation of these highland habitat "islands" from other mountain ranges and their location in this land bridge between North and South America have encouraged both the mix of northern and southern species and the rise of endemic species in all taxa. The striking variety of vegetation types across steep elevational gradients and among the various mountain massifs in this ecoregion have produced very high regional plant biodiversity (high beta-diversity). The Talamanca Range alone is estimated to contain about 90 percent of Costa Rica's known flora. La Amistad International Park, which contains protected area in both countries, contains some 10,000 vascular and approximately 4000 non-vascular plant species, including several hundred endemic taxa. (Davis et al. 1997) Forests above 1200 m in Costa Rica's Monteverde reserve complex in the north of the ecoregion support at least 1708 species of vascular plants, including over 440 tree species. This high richness is due chiefly the great diversity of orchids (291 species), ferns (175 species), and other epiphytes. Over 30 percent of the ecoregion's flora and over 50% of the high mountain flora of Costa Rica and western Panama is considered endemic to those zones.
Similarly, over half the avifauna of the highlands of Costa Rica and western Panama is endemic to this region. Almost 85 percent of the species with restricted geographic ranges are dependent on forest; most of these are species endemic to the Costa Rica-Chiriqui highlands. Endemism among amphibians is also high, (Young et al. 1999) and at least seven small mammals are considered regional endemics.(Palminteri et al. 1999)
Seismically induced phenomena, volcanism, and landslides (triggered by torrential rains or earthquakes) are the major natural disturbances influencing the montane forest units within the Talamancan Range. The resulting steep slopes and nutrient-deficient soils insure that this ecoregion harbors some of the most intact in Central America. The La Amistad International Park, one of the largest reserves in Central America, consists of over 400,000 hectares of relatively intact montane forest. These larger blocks of intact forest are essential for preserving remnant populations of harpy eagles (Harpia harpyja) and they protect breeding grounds of threatened and endangered birds endemic to the highland forests of this ecoregion, such as: resplendent quetzal (Pharomacrus mocinno), three-wattled bellbird (Procnias tricarunculata), bare-necked umbrellabird (Cephalopterus glabricollis), and black guan (Chamaepetes unicolor). The first three of these birds migrate seasonally to lower elevations, demonstrating the importance of not only maintaining intact highland habitats but also connecting them to neighboring intact middle and lower elevations. In fact, over 65 (or over ten percent) of the bird species found here migrate altitudinally.
The Atlantic middle elevations also contain some of the most rare species of butterflies Central America, as well as some of the world's highest butterfly species richness. Populations of crested eagle and painted parakeet were recently discovered in Cerro Hoya on the Azuero Peninsula.
The Talamanca ecoregion presently retains almost 75 percent of its original forest cover, which is distributed patchily over the isolated highland zones of the Tilaran and Talamanca Ranges. The largest forest block occurs in and around the La Amistad Biosphere Reserve. Deforestation, even in the Talamancan highland oak forests, has proceeded since the 1950s at an extremely high rate. The endemic oak species are also valued for their excellent properties to produce charcoal, while rare tree species such as Podocarpus are very sensitive to exploitation.
The Talamanca montane ecoregion's high biological diversity and endemism, as well as its steep topography have encouraged the Costa Rican and Panamanian governments to establish a series of reserves with varying degrees of protection. A full 40 percent of the ecoregion is under protection, in national parks such as the La Amistad, Chirripó, Braulio Carrillo, Volcán Poas, Volcán Baru, Rincón de la Vieja, and the Monteverde cloud forest reserve complex. Like most protected areas in Mesoamerica, the montane parks of the Talamancan forests lack full edological connectivity and regulatory oversight, and do not represent the gamut of ecosystems needed to support altitudinal migrants. For example, they do not allow for altitudinal movement of species. Even La Amistad protects primarily highland habitats over 2000 m while largely missing Pacific slope middle and lower elevations.
Types and severity of threats
Despite the steep slopes and poor soils of these forests, continued illegal logging, squatting, and clearing of land for cattle pasture are making small in-roads into the remaining large forest blocks, reducing connectivity among habitat blocks within the ecoregion and between it and neighboring ecoregions. Kappelle cites the conversion of oak forests to pasture and cropland as the primary cause of erosion in the Talamancan highlands; compaction by cattle of the soil on steep slopes exacerbates the problem, causing runoff and loss of both soil and water resources While the Talamanca Montane forest is relatively well protected, the recent but drastic elimination of middle elevation habitats in surrounding ecoregions has isolated the highland reserves and made their populations vulnerable to genetic degradation. Furthermore, cloud forests are particularly sensitive to climate change, and their location on mountain tops leaves them little chance for adaptation to climatic shifts. Many montane amphibians, such as Monteverde's golden toad (Bufo periglenes), have disappeared from some or all of their ranges for reasons still undetermined by science. Maintaining and restoring forest cover in more than just the highest elevations will benefit populations and ecological processes in both the short and long terms but must be supplemented with research on impacts of regional and global human activities on montane systems.
Justification of ecoregion delineation
The montane forests of the Talamanca and Cordillera Central of Costa Rica and Panama are host to a diverse and unique association of flora and fauna – which share components with both North and South America and of the Caribbean and Pacific slopes. Many endemic species are found here, and this archipelago of montane habitats hosts high levels of beta-diversity and endemism. Our linework follows Tosi’s Holdridge Life Zones – and encompasses the premontane rain forest, lower montane rain forest, montane rain forests, small patches of subalpine rain páramo, and all other lize zones enclosed in this broader matrix. In Panama our linework follows UNDP to include the lower montane wet forest, lower montane rain forest, montane wet forest, montane rain forest, premontane rain forest, and premontane wet forest life zones.
The early exploration of the ecoregions of Panama has scant recording prior to the year 1848. Coastal probing and mapping of the Caribbean shores of present day Panama occurred as early as 1501 and 1503 by Rodrigo de Bastidas and Christopher Columbus. Further recording of some basic coastal biotic conditions were made by Vasco Núñez de Balboa and Gaspar de Espinosa in the early sixteenth century, with the latter conducting interior reconnaisance into the Pacific lowland forests at least as far inland as the town of Santiago.
Josef von Warcewicz was a mid nineteenth century european biological explorer, whose specialties were orchids and hummingbirds. He ventured further into western Panama than any previous scientist, probing not only the Volcan Baru area, but reaching the Caribbean shores at Bocas del Toro.(Heckadon-Moreno. 2004) He claimed that the Talamancan montane forests on the eastern slopes of Volcan Baru to be a "paridise for orchid collectors". He is reputed to have made the first recorded ascent to the volcano rim. Slightly later in the 19th century Wilmot Brown Jr. further recorded transects on the eastern and southern slopes of Volcan Baru. Brown noted very dense birdlife at elevations of 900 meters, which is the approximate start of the montane moist forests. Above the cloud forest he observed an unusual high montane forest belt commencing at approximately 2550 m, where stunted tree forms were covered by "cold saturated mosses". Brown recorded the treeline of the volcanic slopes at around 2800 m elevation.
Additional data on the ecoregion
- For a terser summary of this entry, see WWF WildWorld profile of this ecoregion.
- Boza, M. A. 1996. El corredor biológico Mesoamericano. In Informe de la reunión de la comisión técnica sectorial binacional de recursos naturales, Proyecto Binacional de Manejo y Conservación de la Reserva de la Biósfera La Amistad Costa Rica-Panamá. Boquete, Panama.
- Clark, K. L., R. O. Lawton, and P. R. Butler. 2000. The physical environment. In N. M. Nadkarni, and N.T. Wheelwright, editors, Monteverde: Ecology and conservation of a tropical cloud forest. New York: Oxford University Press. ISBN: 0195133102
- Davis, S.D., V.H. Heywood, O. Herrera MacBryde, J. Villa-Lobos and A.C. Hamilton, editors. 1997. Centres of Plant Diversity. A Guide and Strategy for their Conservation. Volume 3. The Americas. IUCN Publications Unit, Cambridge, U.K. 562 pp.
- DeVries, Philip. 1987. The butterflies of Costa Rica and their natural history. Volumes 1 and 2. Princeton: Princeton University Press. ISBN: 0691028893
- Delgado, F. 1985. Present situation of the forest birds of Panama. In A. W. Diamond, and T. E. Lovejoy, editors. Conservation of tropical forest birds. ICBP Technical Publication No. 4. UK.:International Council for Bird Preservation. ISBN: 0946888051
- Dirección General Forestal (DGF) de Costa Rica. 1989. Forest cover map of Costa Rica. San José.
- Haber, W. A. 2000. Plants and vegetation. In N. M. Nadkarni, and N. T. Wheelwright, editors, Monteverde: Ecology and conservation of a tropical cloud forest. New York: Oxford University Press. ISBN: 0195133102
- Heckadon-Moreno, S. 2004. Naturalists of the Isthmus of Panama. Smithsonian Tropical Research Institute
- INRENARE (now ANAM). 1992. Forest cover map of Panama.
- Kappelle, M. 1996. Los Bosques de Roble (Quercus) de la Cordillera de Talamanca, Costa Rica. Costa Rica: University of Amsterdam/Instituto Nacional de Biodiversidad. ISBN: 9968702056
- Palminteri, S., G. Powell, A. Fernandez, and D. Tovar. 1999. Talamanca Montane-Isthmian Pacific Ecoregion-Based conservation plan: Preliminary reconnaissance phase. Report to WWF-Central America.
- Powell, G. 2000. Personal communication.
- Pounds, J. A., M. P. Fogden, and J. H. Campbell. 1999. Biological response to climate change on a tropical mountain. Nature vol 398, no. 6728: 611-615.
- Pounds, J. A., 2000. Amphibians and reptiles. In N. M. Nadkarni, and N. T. Wheelwright, editors, Monteverde: Ecology and conservation of a tropical cloud forest. New York: Oxford University Press. ISBN: 0195133102
- Reid, F. 1997. A field guide to the mammals of Central America and Southeast Mexico. New York: Oxford University Press. ISBN: 0195064011
- Stiles, F. G. 1985. Conservation of forest birds in Costa Rica: problems and perspectives. In A. W. Diamond, and T. E. Lovejoy, editors. Conservation of tropical forest birds. ICBP Technical Publication No. 4. United Kingdom: International Council for Bird Preservation. ISBN: 0946888051
- Stiles, F. G., and A. F. Skutch. 1989. A guide to the birds of Costa Rica. New York: Cornell University Press. ISBN: 0801496004
- Tosi Jr., J.A. 1969. Republica de Costa Rica: mapa ecológico. Map 1:750,000. Tropical Science Center, San Jose, Costa Rica.
- UNDP. 1970. Mapa ecólogico de Panama. Map 1:5,000,000. Programa de las Naciones Unidas para el Desarrollo, Panama City, Panama.
- Young, B. E., G. Sedaghatkish, E. Roca, and Q. Fuenmayor. 1999. El estatus de la conservación de la herpetofauna de Panamá. Resumen del Primer Taller Internacional sobre la Herpetofauna de Panama. The Nature Conservancy y Asociación Nacional para la Conservación de la Naturaleza (ANCON).
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