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SIERRA DE LAS MINAS REGION
|Location: The Sierra de las Minas is in eastern Guatemala between about latitudes
15°07'-15°21'N and longitudes 89°18'-89°45'W.
Area: Region 4374 km², reserve 2363 km².
Altitude: 150-3015 m.
Vegetation: The region has cloud-forest associations, lower montane moist, wet and rain forests, premontane wet and rain forests, tropical and premontane dry forests, and thorn scrub.
Flora: Extremely diverse (over 2000 species recorded); high species endemism; several disjunct taxa; southern limit for several northern genera (e.g. Acer, Taxus).
Useful plants: Major timber reserves, especially conifers, and some remnants of lowland hardwood forests in north and south-east. 13 conifer species in region, which is a major centre for Pinus. Other useful species include tree ferns (for their adventitious roots), bamboo (for cottage industries) and many medicinal and food plants. Region potentially rich in phytogenetic resources.
Other values: Watershed protection - Sierra de las Minas is main source of water for local irrigation, light industry and household use. 62 permanent streams begin in upper elevations of BR. The scenery is important for development of tourism.
Threats: Expansion of agricultural frontier, logging, colonization, roads, over-hunting.
Conservation: Nearly 55% of region declared a Biosphere Reserve in 1990. A management plan approved in 1992 and active management being implemented, but facing heavy pressure from timber interests.
Map 25: CPD Site MA14
The Sierra de las Minas forms a mountain chain 15-30 km wide extending from Lake Izabal westward for 130 km (Map 25). It covers 4374 km² in Guatemala's departments of Izabal, Zacapa, El Progreso, Baja Verapaz and Alta Verapaz. The range is bordered to the south by the Motagua River and to the north by the Polochic River, both of which flow in valleys formed by geological faulting. Most of the 62 permanent streams arising in the Sierra de las Minas flow directly into either the Polochic or Motagua.
In the north, the sierra descends abruptly to the Polochic Valley. An unbroken ridge above 2100 m extends from near Chilascó through Cerro Raxón (3015 m) for 65 km east beyond Montaña El Imposible (2610 m). To the east, elevations drop gradually toward Lake Izabal and the Motagua River. The southern slopes are less steep and the forests more accessible. To the west, the sierra is bounded by the Salamá and San Jerónimo valleys, of igneous origin. To the north, Palaeozoic rock formations include schists and gneisses, which grade into Tertiary metamorphosed amphibolites and marbles to the south. There are belts of serpentine along the north-western margin and the southern side of the range (Weyl 1980).
The soils are generally shallow, often lateritic, 25-50 cm deep and consist of alluvial clays and loams. Sixty-five percent are on slopes highly susceptible to erosion. The Polochic Valley contains rich alluvial soils.
The Sierra de las Minas is heavily influenced by the north-east trade winds from the Caribbean Sea. Rainfall varies from over 4000 mm on mountain peaks and 2000 mm on Polochic-facing slopes to less than 500 mm in western Motagua Valley around Zacapa. In general rainfall is seasonal, especially on southern slopes, with marked decreases from January to April.
Temperatures vary considerably; information is lacking, especially for higher elevations. In the arid Motagua Valley mean temperatures average 24°C, ranging between 11.5°-41°C; at intermediate elevations temperatures may range between 5°-25°C; and at 1750 m and above light frosts are regularly experienced between December and March.
The higher slopes of the sierra are almost uninhabited, whereas the Motagua and Polochic valleys support ethnically distinct populations. To the south in the Motagua Valley the population is "ladino" (mestizo), with numerous small towns and villages, among them Río Hondo with c. 15,000 inhabitants. Subsistence crops are grown, such as maize, beans and cabbage, together with tomatoes, melons, tobacco and cucumber as cash crops. At mid-elevations coffee and cardamom farms may be found, together with low density cattle-farming and lumber extraction, particularly pines for electric posts. Hunting is a popular pastime.
The Polochic slopes are inhabited by the Q'eqchí to the north and the Poqomchí and Achí to the west. These lower slopes and valley floors are devoted to large farms with cattle, sugarcane and rice as major sources of income, and coffee and cardamom above c. 600 m. The steeply forested upper slopes are being increasingly invaded by Amerindian families displaced from lower elevations by the large farms. This is a significant threat to the Biosphere Reserve, which can only be mitigated by emphasis on sustainable resource use.
Two vegetation types of the sierra are especially significant in species diversity, endemic species and uniqueness to Mesoamerica: lower elevation thorn scrub and cloud forest.
The thorn scrub represents one of the driest areas of Central America, dominated by cactus and Acacia species, and is much threatened by light industry, cattle-ranching and irrigated crops. Only 200-300 km² of this formation remain; local communities have expressed interest in setting aside tracts for conservation. Most of the formation has already been disturbed to varying extents. The most abundant species include Cephalocereus maxonii, Nyctocereus guatemalensis, Opuntia spp., Pereskiopsis, Acacia spp. and Guaiacum sanctum.
The cloud forest (picture), in the lower montane rain-forest zone (Holdridge system), covers c. 1300 km² more than 65% is probably primary forest. This may represent the largest unbroken extent of cloud forest in Mesoamerica. The lower elevational limits are 1500 m on northern slopes, 1100 m on the south-eastern edge and 1900-1950 m on southern aspects of the range. Species composition varies depending on elevation. The highest elevations (2700 m and above) have forests with Pinus ayacahuite, Abies guatemalensis (picture), Quercus spp., Taxus globosa, Alnus, etc. From c. 2000-2700 m broadleaved forests predominate, with important canopy trees being Quercus spp., Lauraceae (Persea donnell-smithii, P. sessilis, P. schiedeana), Podocarpus oleifolius, Magnolia guatemalensis, Alfaroa costaricensis, Billia hippocastrum and Brunellia mexicana.
Cloud-forest associations also occur at lower elevations in premontane rain forest and premontane wet forest down to 1000 m above Lake Izabal and the Polochic-facing slopes. Most of these associations are as yet poorly known, but appear to have many interesting species and would repay further study. For instance the palm Colpothrinax cookii, extirpated at its type locality, was recently found here. There are several orchid species of mainly South American genera, such as Paphinia and Kegeliella.
The conifer forests, which include 13 species, are important lumber and germplasm reserves. Attempts are being made to incorporate these forests into sustainable harvesting systems, especially the mid-elevation lower montane moist forests dominated by Pinus patula subsp. tecunumanii and P. oocarpa. Associated species include Quercus spp., Liquidambar, Acer skutchii and Tillandsia usneoides. At lower elevations in premontane wet forests are scattered extensions of Pinus caribea, in association with Curatella americana and Quercus spp. especially where there are limestone outcrops. Juniperus comitana and Cupressus lusitanica occur as relicts in scattered stands at 1700-1900 m; and cloud forests contain Abies guatemalensis, Taxus globosa, Podocarpus oleifolius and Pinus ayacahuite. On the southern slopes at 1600-1900 m, a very interesting association includes several palm species.
To the south and west, lower montane wet forest occupies small extensions characterized by the presence of Quercus spp., Pinus oocarpa, Alnus jorullensis, Prunus barbata and P. brachybotra. On the dry southern slopes of the sierra up to c. 900 m, tracts of deciduous tropical dry forest grade into premontane dry forest. The species include Quercus spp., Bursera simaruba, occasional Cedrela odorata, Ceiba aesculifolia, Leucaena guatemalensis, Cochlospermum vitifolium, Gliricidia sepium and Pseudobombax ellipticum.
In restricted areas of the sierra, marble outcrops support an especially interesting association that depends mainly on cloud-borne precipitation. Epiphyte-laden oak forests contain endemic agaves (e.g Agave minarum), Beaucarnea guatemalensis and epiphytic cacti. This association contrasts dramatically with surrounding forests of Pinus oocarpa and P. patula subsp. tecunumanii on dry soils.
The flora of the Sierra de las Minas is represented in the Flora of Guatemala (Standley, Steyermark and Williams 1946-1977). Steyermark collected extensively on the Motagua side of the sierra in Zacapa and El Progreso. Because of its general inaccessibility, the flora of the Polochic drainage is poorly known, and there are areas on both sides where there has been almost no exploration. The orchids are probably best known: 230 species in 25 genera (Ames and Correll 1952-1953; Correll 1965; Dix and Dix 1990); c. 30% of the species known from Guatemala occur in the Sierra de las Minas (Dix and Dix, in prep.). Among these are endemic species (e.g. Epidendrum sobraloides) and others known from Guatemala only in this region.
The Sierra de las Minas is surrounded by heavily deforested regions dedicated to coffee, cardamom and similar crops. As a result, this region represents a last refuge for many species (e.g. Colpothrinax cookii) described from the extensively explored and better known Alta Verapaz Department and Sierra de Chamá.
The Sierra de las Minas with close to 2000 recorded species is rich both in endemic species - at least 70 - and in species at the northern or southern limit of their ranges. North temperate elements extending to the sierra include Acer skutchii, Liquidambar styraciflua and Taxus globosa. Southern elements include Podocarpus species.
In addition to the species endemic to the sierra, 35% of the species in the Flora of Guatemala that were considered endemic to Guatemala can still be found in the sierra. Many of these species are gone from other Guatemalan localities.
In general, the resource potential for the region is high, but most species are under-utilized.
Timber extraction is a major source of income, especially from the southern slopes. The species most frequently exploited include Pinus oocarpa, P. patula subsp. tecunumanii and P. caribea, used especially for utility poles, railway sleepers and furniture. Most of the utility poles produced in Guatemala come from this region. There is a large potential for developing conifer plantations on deforested slopes in all of the sierra. The rich conifer diversity could lead to a sustainable seed-harvesting industry. In the Polochic drainage and the lower eastern slopes Cedrela odorata, Dalbergia (rosewood) and Vochysia spp. (San Juan) have been harvested in the past, but recent information on available resources is lacking.
The adventitious roots of several tree-fern species (Dicksonia, Cyathea, Alsophila) are harvested to produce pots or the fibre is used as substrate for growing ornamental plants. Bamboo is used in basket-making.
Medicinal plants abound. These include Ocimum spp., Crescentia alata, several Rubiaceae (e.g. Borreria ocymoides, Randia armata, Hamelia patens), Dorstenia contrajerva, Neurolaena spp. and many Solanaceae. Several species of Cucurbitaceae and Solanaceae represent potential germplasm resources of food plants, including local varieties of tomato.
With appropiate studies, there is development potential for producing and selling ornamental plants such as begonias, palms, orchids, bromeliads and peperomias, and medicinal plants, including species yielding contraceptives and anti-malarial drugs.
The Sierra de las Minas is important as a generator of orographic rainfall for the surrounding Polochic and Motagua valleys, giving rise to the 62 permanent streams. In the north, farmers depend on these rains for coffee, cardamom and rice production and for cattle-farming. To the south, this is the only rainfall reaching the north-eastern side of the arid Motagua Valley. As well as the basic needs of the local people, agricultural crops (e.g. melon, tobacco, grapes, citric fruits, tomatoes) depend on irrigation provided by the small rivers flowing from the sierra. Light industry, also dependent on a steady water supply, includes soft drinks, fertilizer and paper-recycling plants, and hydroelectricity is generated at the Río Hondo station. However, water flow has been reduced over 40% during the last 10 years and the water table has dropped, probably because of the loss of vegetation.
The fauna of the sierra is very diverse. The region harbours over 800 bird species. Significantly, the cloud forests support the largest remaining population of Guatemala's national bird, the quetzal (Pharomacrus mocinne). The Sierra de las Minas is in the Northern Central American Highlands Endemic Bird Area (EBA A14), which includes a number of mountain ranges in southern Mexico (e.g. Chiapas), Guatemala, El Salvador, Honduras and north-west Nicaragua. There are 21 species of birds confined to this EBA, and a large proportion occur in the Sierra de las Minas. The enigmatic and threatened horned guan (Oreophasis derbianus) was recently found in this mountain range (Howell and Webb 1992).
Other animals include white-tailed deer (Odocoileus virginianus), brocket deer (Mazama americana), peccaries (Tayassu pecari), jabalí (Tayassu tajacu), puma (Felis concolor), howler monkeys (Alouatta) and many small rodents and bats. The small mammals have not been carefully surveyed, but a detailed study began in 1992. Reptilian and amphibian diversity is high, with over 60% of the species known from Guatemala present in the sierra (Campbell 1982). Schuster (1992) described endemic insects (Passalidae) from the region and considers that the area may have high faunal diversity.
Scenic values are important and could form the basis for a sustainable tourist industry. The contrast in a drive of 3-4 hours between the Motagua Valley's arid thorn scrub dominated by cacti and acacias and the misty peaks of the epiphyte-laden cloud forests is impressive. Additional tourist attractions that could be sustainably managed include marketing of Amerindian textiles and handicrafts.
Three pre-Columbian archaeological sites within the BR are Río Zarquito - of the Classic period (Maya and Chorti), and Tinajas and Pueblo Viejo - of the post-Classic period (Maya and Q'eqchí). San Agustín Acasaguastlán represents an early Colonial mission.
The water resources are the region's most valuable asset. The sierra provides water for irrigation in the dry Motagua Valley for growing melons, tobacco, tomatoes, grapes and other crops. The Río Hondo hydroelectric station produces 2% of Guatemala's electricity.
The main direct economic values are from the forest for lumber and fuelwood, which usually is the only energy source for domestic cooking. Some income is derived from bromeliad and tree-fern harvesting. Coffee and cardamom are important cultivated products.
Conserving the high-elevation forests is a first priority because both the water resources and the incipient tourist industry depend on them. Increased erosion, and decreased rainfall with 40% loss of water flow, have been documented already (Fundación Defensores de la Naturaleza 1992).
Deforestation with consequent erosion constantly threatens. Indiscriminate timber extraction has resulted in a removal rate beyond the system's capacity for sustainable management, with probable germplasm degradation. There also are insufficient reforestation projects.
On the Motagua Valley slopes, fire destroys large areas of forest every year as the agricultural frontier advances. Moreover, this devastation occurs as well on steep slopes that are not adequate for agriculture, and their natural regeneration is very slow.
Colonization by displaced Q'eqchís is a potential threat because of their non-sustainable cut, slash and burn monoculture and lack of soil conservation practices. Vegetable cultivation on a large scale is being promoted by development agencies, but is not necessarily a good idea because insufficient attention has been given to erosion control and soil degradation in these fields and to loss of water quality. Indiscriminate hunting for subsistence and recreation is a problem. Large-scale community education is needed, as well as ongoing studies on the effects of agricultural practices on soil structure.
In October 1990, the Guatemalan legislature decreed an area of 2363 km² in the Sierra de las Minas as a Biosphere Reserve and appointed Fundación de los Defensores de la Naturaleza as its manager. The passage of this law was precedent setting (Fundación Defensores de la Naturaleza 1990). Not only is it the first time that a non-profit private organization (NGO) has been given the management of a major Guatemalan reserve, but there also is an innovative relationship with local communities, which share in overseeing the management process. UNESCO-MAB has recognized the reserve as a part of the world network of Biosphere Reserves.
Defensores de la Naturaleza was founded in 1983; its goals are preservation of the Sierra de las Minas Biosphere Reserve, environmental education of students and the general public, and education of Guatemalan leaders on the nation's conservation needs. Defensores works closely with other organizations through cooperative agreements.
The BR is zoned into a nuclear area (1057 km²), which contains 81% of the existing cloud forests; sustainable-use zone (346 km²); experimental forest recovery zone (42 km²); and buffer zone (920 km²).
The (U.S.) Nature Conservancy (TNC) has included the Sierra de las Minas in its Parks in Peril Program (TNC 1990) and contributed funds for land purchase by Defensores, and TNC also is actively involved in developing a conservation strategy. It is creating information databases through the Centro de Datos para la Conservación (CDC) at the Centro de Estudios Conservacionistas (CECON), which is the academic unit of the Universidad de San Carlos de Guatemala that is responsible for promoting field research and conservation of renewable resources.
Other organizations involved in conservation and research in the sierra include the Universidad del Valle de Guatemala, with biodiversity studies on cloud-forest flora and fauna (such as epiphytes, insects and small mammals) and on sustainable use of tree fern and bamboo in the buffer zone. CARE, as a component of Proyecto PACA (Programa Ambiental para Centroamérica), is heavily involved in supporting Defensores in its enviromental education and sustainable-use programmes.
Several local organizations have been formed. The oldest, FUNDEMABV (Fundación del Medio Ambiente para Baja Verapaz), has enviromental education programmes in local schools, and others are developing programmes in Alta Verapaz, Zacapa and Izabal departments.
It appears that the BR is now established and effective programmes are underway. Hopes are high that good management, active local NGO participation, and positive relationships with indigenous peoples will allow this area to become a model for conservation and sustainable development in Guatemala.
Ames, O. and Correll, D.S. (1952-1953). Orchids of Guatemala. Fieldiana, Botany 26: 1-727.
Campbell, J.A. (1982). The biogeography of the cloud forest herpetofauna of Middle America, with special references to Sierra de las Minas. Ph.D. dissertation. University of Kansas, Lawrence. 322 pp.
Correll, D.S. (1965). Supplement to the orchids of Guatemala and British Honduras. Fieldiana, Botany 31(7): 177-221.
Dix, M.A. and Dix, M.W. (1990). La Sierra de las Minas: su diversidad orquideológica. In Tercer Encuentro Latinoamericano de Orquideología. Pp. 12-14.
Dix, M.A. and Dix, M.W. (in preparation). An annotated revised check list of the orchid flora of Guatemala.
Fundación Defensores de la Naturaleza (1990). Estudio técnico para dar a Sierra de las Minas la categoría de reserva de la biósfera. 44 pp.
Fundación Defensores de la Naturaleza (1992). Reserva de la Biósfera Sierra de las Minas. Plan maestro 1992-1997. 54 pp.
Howell, S.N.G. and Webb, S. (1992). New and noteworthy bird records from Guatemala and Honduras. Bull. Brit. Orn. Club 112: 42-49.
Schuster, J.C. (1992). Biotic areas and the distribution of passalid beetles (Coleoptera) in northern Central America: post-Pleistocene montane refuges. In Biogeography of Mesoamerica. Tulane Studies Zoology and Botany, Supplementary Publ. 1: 285-292.
Standley, P.C., Steyermark, J.A. and Williams, L.O. (1946- 1977). Flora of Guatemala. Fieldiana, Botany 24.
TNC (1990). Parks in peril: a conservation partnership for the Americas. The Nature Conservancy (TNC), Arlington, Virginia. 25 pp.
Weyl, R. (1980). Geology of Central America. Gebruder Borntraeger, Berlin. 373 pp.
This Data Sheet was written by Dr Margaret A. Dix (Universidad del Valle de Guatemala,
Departamento de Biología, Apdo. Postal 82, Guatemala City, Guatemala).
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