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SIERRA DE MANANTLAN REGION
The Sierra de Manantlán (picture) is a north-western portion of the Sierra Madre del Sur c. 50 km inland from the Pacific Ocean (Map 17), and ranges from c. )400 m at Casimiro Castillo (La Resolana) to 2860 m centrally at Cerro La Bandera (El Muñeco). The Sierra de Manantlán lies in two hydrographic regions and contributes to the Armería, Marabasco and Purificación watersheds. The western and central portions of the range are of igneous origin, from the Tertiary (extrusive) and Cretaceous (intrusive); the eastern portion is of sedimentary Late Cretaceous origin (Jardel-P. 1992).
The region's climate (in the Köppen system) ranges from subhumid warm to semi-warm, to subhumid temperate. Mean temperatures range from 27°-12°C depending on elevation, with some frost. The median annual rainfall is c. 800 mm in the driest northern lowlands, to 1800 mm at higher elevations. The rainy season is in summer, and fog is frequent above 1500 m (Jardel-P. 1992).
The Sierra de Manantlán is in a transition zone between the Neotropical and Holarctic biogeographic regions (Rzedowski and McVaugh 1966). Additionally, lowland tropical forests change to temperate forests at higher elevations. The region's complex topography, geologic substrates and climate are combined with the history of human influences into an intricate mosaic of extraordinarily different vegetation types within a relatively limited area. Transitions between vegetation types generally are gradual, but can be abrupt (Vázquez-G. et al. 1990; Jardel-P. 1992).
Tropical dry forest
Tropical subdeciduous forest
Several economically valuable species are extracted from this type of forest, including Cedrela odorata and Swietenia humilis; the inhabitants gather edible and medicinal plants (Robles-H. et al., in press). Principal threats are the logging, and conversion for agriculture and pasturage.
The pine-oak forest has been greatly affected by human activities and its composition reflects this impact. The pine forests are mostly patches of second growth. The climax vegetation in sites currently occupied by the pines corresponds to pine-oak forest in dry environments or cloud forest in humid areas (Jardel-P. 1991). Cloud-forest tree species and some shade-tolerant oaks colonize patches of land dominated by the pines, and can replace them successionally (Sánchez-Velásquez 1988; Saldaña-A. and Jardel-P. 1992).
Mesophyllous mountain forest (cloud forest)
This type of vegetation has many species used for many purposes, but it is threatened principally by logging (e.g. for Fraxinus uhdei, Magnolia iltisiana, Juglans major, Tilia mexicana) and cattle-ranching.
The discovery of Zea diploperennis (picture) in 1977, a disease-resistant perennial relative of maize (Iltis et al. 1979), sparked intensive study of the plants in the Sierra de Manantlán. Currently, 85-90% of the vascular flora in the c. 1400 km² of the sierra may have been recorded - 2500 species (Vázquez-G. et al. 1990).
The Sierra de Manantlán is part of a western zone considered a centre of diversification for several families, including Malvaceae, Compositae and possibly Euphorbiaceae and Malpighiaceae (Vázquez-G. et al. 1990; Fryxell 1988; McVaugh 1984). Generic diversification includes Periptera, Jaliscoa, Tripsacum and Zea. Endemics reported from the Sierra de Manantlán include Zea diploperennis, Agrostis novogaliciana, Populus guzmanantlensis ("álamo"), Croton wilburii, Cnidoscolus autlanensis and Vernonia pugana.
The tropical dry forest of western Mexico may be the most diverse in woody species in the world. The montane mesophyllous forest is considered relictual of the Tertiary humid forests in northern North America. The region is also important as part of a transitional area which has a mix of species with boreal and tropical affinities.
Some of the species threatened due to selective exploitation are Cedrela odorata, Swietenia humilis, Fraxinus uhdei, Juglans major, Tilia mexicana, Abies religiosa, Guaiacum coulteri, Talauma sp. and Magnolia iltisiana.
Preliminary data from current studies indicate that local rural communities have a profound knowledge of the utility of the flora in the Sierra de Manantlán (Benz et al. 1994; Robles-H. et al., in press). Based on interviews with the local inhabitants, over 500 species are utilized - yet only 179 are used in more than one of the ten communities in the study area. About 284 species have more than one use; 300 are used for traditional medicinal purposes, 226 for timber, 170 for food and 100 for forage. Fruits of Stenocereus queretaroensis, Jacaratia mexicana, Pithecellobium dulce and Ternstroemia lineata are among those gathered for marketing.
The Sierra de Manantlán contains wild relatives of maize - the "teosintes" Zea diploperennis and Z. mays subsp. parviglumis, and of beans - Phaseolus coccineus and P. vulgaris (Benz 1988; Gepts 1988). The Zea germplasm is already considered to be of monumental economic value for the world's agriculture (e.g. Vietmeyer 1979; Nault and Findley 1982). For example, Zea diploperennis ("milpilla") is resistant to various viruses that have infected cultivated maize.
The region's cultivated maize (Zea mays subsp. mays) includes two of the most primitive traditional varieties in Mexico, one of which is only found in small isolated towns, so this land race perhaps is being lost. Wild relatives of crops may survive and evolve with traditional agricultural practices of slash-and-burn cultivation ("coamil") and cattle-ranching. The traditional agriculture practised in the region may be responsible for the genetic amplitude of the teosintes and very probably the wild beans (Sánchez-G. and Ordaz-S. 1987; Benz, Sánchez-Velásquez and Santana-Michel 1990). These plants demonstrate the necessity to conserve traditional agricultural systems (Guzmán-M. and Iltis 1991).
Preliminary surveys indicate that the Sierra de Manantlán may contain c. 40 widespread tree species of economic value, primarily to the silvicultural industry. Examples include Pinus douglasiana, P. durangensis (see picture), P. herrerae, P. oocarpa, P. pseudostrobus and some Quercus spp.
Social and environmental values
Water is one of the most important resources of the region. About 400,000 people rely on the sierra's water catchment for industry, agriculture and other purposes (Jardel-P. 1992). The agricultural crops are grown in the valleys, for local and export markets. None of the land in the Sierra de Manantlán Biosphere Reserve has been purchased by governmental authorities - it represents a vast zoning experiment, with 20% in indigenous communities, 40% community-owned ("ejido") lands and 40% privately owned. About 9000 people inhabit the BR, and a biological research field station is located within its western area (at 19°35'N, 104°16'W). Cooperation among the reserve's various parties is crucial (Sheean-Stone 1989).
The Sierra de Manantlán is an important refuge for animals (Sheean-Stone 1989; Jardel-P. 1992), including threatened species such as the jaguar. So far, 108 species of mammals are known from the region - 25% of Mexico's mammals; at least 12 of the species are endemic to montane areas of western Mexico and 2 subspecies to the reserve. The bird tally for the general area is 336 species - 30% of Mexico's birds, including the locally rare lilac-crowned amazon or "cotorra" (Amazona finschi), military macaw or "guacamaya verde" (Ara militaris) and golden eagle or "águila real" (Aquila chrysaetos); 30% of the species are totally or partially migratory, and 32 species are endemic to western and central Mexico. Lists have been compiled for the species of reptiles (60) and amphibians (20). The fishes (16 species) have a high proportion of endemics. There are 180 or more families of insects represented in the reserve.
In the mountains of central Mexico (Endemic Bird Area A11) are seven bird species of restricted range; four occur in the Sierra de Manantlán: long-tailed wood-partridge (Dendrortyx macroura), grey-barred wren (Campylorhynchus megalopterus), green-striped bush-finch (Atlapetes virenticeps) and collared towhee (Pipilo ocai). The threatened black-capped vireo (Vireo atricapillus), which breeds in south-eastern U.S.A. and Coahuila, Mexico, winters in the highlands of western Mexico and probably within this sierra.
Timber has been one of the most coveted resources in the Sierra de Manantlán. Between 1940-1985, the timber industry used intensive poorly planned extraction methods, resulting in a network of logging roads; the agricultural communities, which are the forest owners, received marginal benefits (Jardel-P. et al. 1989). Currently logging has been suspended, but private timber companies exert pressure to resume. The management plan for the reserve permits sustainable forest utilization in the buffer zone, under control of the agrarian communities that own the land (Jardel-P. 1992).
Cattle-grazing, goat-browsing and human-induced fires are other major causes of habitat degradation (Jardel-P. 1992). Only c. 30% of the region remains in good condition, and forest destruction was occurring at a rate of 20 km² per year. However, fairly recently the Jalisco government has increased protection.
Discovery of the rare Zea diploperennis brought the Sierra de Manantlán to the attention of national and international scientific communities and the public worldwide a famous, indeed classic example of the need to preserve genetic diversity in situ (Iltis 1983; Halffter 1987). Further ecological studies have indicated that the sierra is significant not only because of the diploid wild maize, but also for the sierra's generally distinctive flora and fauna and its forestry potential. Swietenia humilis (Pacific Coast mahogany) is in Appendix II of CITES.
An initial protective step for the region was taken in 1984 when the State of Jalisco purchased 12.5 km at Las Joyas, a private locality with a large population of Zea diploperennis. In 1985 the Universidad de Guadalajara created the Laboratorio Natural Las Joyas de la Sierra de Manantlán (LNLJ). Efforts were directed toward protection of the larger area. The Reserva de la Biósfera de la Sierra de Manantlán was established in 1987 by Presidential decree, created under the auspices of the Jalisco government, with support from the Consejo Nacional de Ciencia y Tecnología (CONACYT), and was recognized by UNESCO's Man and the Biosphere Programme in 1988 (LNLJ 1989; Santana-C., Guzmán-M. and Jardel-P. 1989).
The reserve encompasses 1396 km² of the volcanic Sierra de Manantlán and neighbouring calcareous Cerro Grande to the east. The 345 km² of tropical dry forest in the reserve is the largest area of this formation protected in Mexico, and the 50 km² of cloud forest is the largest protected on Mexico's Pacific slope. The reserve and plan (Jardel-P. 1992) have presented a splendid opportunity to create a model of wise conservation and management of natural resources, with the assistance of the Universidad de Guadalajara's Instituto Manantlán de Ecología y Conservación de la Biodiversidad, which conducts regional multidisciplinary studies through facilities such as the LNLJ, and the full involvement of the local inhabitants (mostly indigenous people) and the nearby communities. For example, it is planned to continue the coamil system in a few restricted areas within the BR so that the milpilla populations can survive.
Map 17. Sierra de Manantlán Region and Biosphere Reserve, Mexico (CPD Site MA6)
Benz, B.F. (1988). In situ conservation of the genus Zea in the Sierra de Manantlán Biosphere Reserve. In CIMMYT, Recent advances in the conservation and utilization of genetic resources: proceedings of the Global Maize Germplasm Workshop. Centro Internacional del Mejoramiento de Maíz y Trigo (CIMMYT), Mexico, D.F. Pp. 59-69.
Benz, B.F., Sánchez-Velásquez, L.R. and Santana-Michel, F.J. (1990). Ecology and ethnobotany of Zea diploperennis: preliminary results. Maydica 35: 85-94.
Benz, B.F., Santana-M., F.J., Pineda-L., R., Cevallos-E., J., Robles-H., L. and DeNiz-L., D. (1994). Characterization of mestizo plant use in the Sierra de Manantlán, Jalisco-Colima, Mexico. J. Ethnobiology 14: 23-41.
Cuevas-Guzmán, R. and Núñez-L., N. (1988). Taxonomía de los pinos de la Sierra de Manantlán, Jalisco. Prof. thesis. Facultad de Agronomía, Universidad de Guadalajara, Jalisco, Mexico. 104 pp.
Figueroa-R., B.L. (1991). Estructura y distribución de las poblaciones de Abies sp. en Cerro Grande, municipios de Tolimán, Jalisco y Minatitlán, Colima. Prof. thesis. Facultad de Ciencias Biológicas, Universidad de Guadalajara, Jalisco, Mexico. 83 pp.
Fryxell, P.A. (1988). Malvaceae of Mexico. Systematic Botany Monogr. 25: 1-522.
Gepts, P.L. (ed.) (1988). Genetic resources of Phaseolus beans: their maintenance, domestication, evolution, and utilization. Kluwer Academic Publishers, Dordrecht, The Netherlands. 613 pp.
Guzmán-Mejía, R. (1985). Reserva de la Biósfera de la Sierra de Manantlán, Jalisco: estudio descriptivo. Tiempos de Ciencia, Univ. Guadalajara, Jalisco, Méx. 1: 10-26.
Guzmán-M., R. and Iltis, H.H. (1991). Biosphere reserve established in Mexico to protect rare maize relative. Diversity 7(12): 82-84.
Halffter, G. (1987). La Reserva de la Biósfera de Manantlán y la conservación in situ de los recursos bióticos. Rev. Soc. Mex. Hist. Nat. 39: 27-34.
Iltis, H.H. (1983). The 3rd University of Wisconsin University of Guadalajara Teosinte Expedition to the Sierra de Manantlán, Jalisco, Mexico: December 28, 1979 to January 21, 1980. Contr. Univ. Wisconsin Herbarium 1(1), 2nd revised edition. University of Wisconsin, Madison. 78 pp. Unpublished.
Iltis, H.H., Doebley, J.F., Guzmán-M., R. and Pazy, B. (1979). Zea diploperennis (Gramineae): a new teosinte from Mexico. Science 203: 186-188.
Jardel-P., E.J. (1991). Perturbaciones naturales y antropogénicas y su influencia en la dinámica sucesional de los bosques de Las Joyas, Sierra de Manantlán, Jalisco. Tiempos de Ciencia, Univ. Guadalajara, Jalisco, Méx. 22: 9-26.
Jardel-P., E.J. (ed.) (1992). Estrategia para la conservación de la Reserva de la Biósfera Sierra de Manantlán. Editorial Universidad de Guadalajara, Guadalajara, Jalisco, Mexico. 312 pp.
Jardel-P., E.J., Cuevas-G., R., León-C., P., León-C., M.A., Mariscal-L., G., Pineda-L., R., Saldaña-A., M.A., Sánchez-V., L.R. and Téllez-L., J. (1989). Conservación y aprovechamiento de los recursos forestales de la Reserva de la Biósfera Sierra de Manantlán. Tiempos de Ciencia, Univ. Guadalajara, Jalisco, Méx. 16: 18-24.
LNLJ (1989). Plan operativo 1989-1990. Reserva de la Biósfera Sierra de Manantlán. Universidad de Guadalajara, Laboratorio Natural Las Joyas de la Sierra de Manantlán (LNLJ), El Grullo, Jalisco, Mexico. Pp. 4-11.
McVaugh, R. (1984). Compositae. Flora Novo-Galiciana 12: 1-1157.
Muñoz-M., M.E. (1992). Distribución de especies arbóreas del bosque mesófilo de montaña en la Reserva de la Biósfera Sierra de Manantlán. Prof. thesis. Universidad de Guadalajara, Jalisco, Mexico. 102 pp.
Nault, L.R. and Findley, W.R. (1982). Zea diploperennis: a primitive relative offers new traits to improve corn. Desert Plants 3: 202-205.
Nixon, K.C. (1993). The genus Quercus in Mexico. In Ramamoorthy, T.P., Bye, R., Lot, A. and Fa, J.E. (eds), Biological diversity of Mexico: origins and distribution. Oxford University Press, New York. Pp. 447-458.
Robles-H., L., DeNiz-L., D., Benz, B.F., Santana-M., F.J., Pineda-L., R. and Anaya-C., M. (in press). Flora útil de la Reserva de la Biósfera Sierra de Manantlán. In Bye, R. (ed.), Memoria del primer encuentro sobre bosque tropical caducifolio. Universidad Nacional Autónoma de México, Mexico, D.F.
Rzedowski, J. and McVaugh, R. (1966). La vegetación de Nueva Galicia. Contr. Univ. Michigan Herb. 9: 1-123.
Saldaña-A., M.A. and Jardel-P., E.J. (1992). Regeneración natural de especies arbóreas en los bosques subtropicales de montaña de la Sierra de Manantlán. Biotam, Univ. Autón. Tamaulipas, Méx. 3(3): 36-50.
Sánchez-G., J.J. and Ordaz-S., L. (1987). El teocintle en México. Systematics and ecogeographic studies in crop genepools. Vol. 2. International Board for Plant Genetic Resources (IBPGR), Rome. 98 pp.
Sánchez-Velásquez, L.R. (1988). Sucesión forestal en la Sierra de Manantlán, Jalisco, México. M.S. thesis. Colegio de Postgraduados, Centro de Botánica, Chapingo, Mexico. 54 pp.
Santana-C., E., Guzmán-M., R. and Jardel-P., E.J. (1989). The Sierra de Manantlán Biosphere Reserve: the difficult task of becoming a catalyst for regional sustained development. In Gregg Jr., W.P., Krugman, S.L. and Wood Jr., J.D. (eds), Proceedings of the symposium on biosphere reserves. 4th World Wilderness Congress. U.S. National Park Service, Washington, D.C. Pp. 212-222.
Santiago-P., A.L. (1992). Estudio fitosociológico del bosque mesófilo de montaña de la Sierra de Manantlán. Prof. thesis. Facultad de Ciencias Biológicas, Universidad de Guadalajara, Jalisco, Mexico. 120 pp.
Sheean-Stone, O. (1989). Mexico's wonder weed. WWF Reports (Gland, Switzerland) (Aug.Sept.): 9-12.
Vázquez-G., J.A., Cuevas-G., R., Cochrane, T.S. and Iltis, H.H. (1990). Flora de la Reserva de la Biósfera Sierra de Manantlán, Jalisco-Colima, México. Universidad de Guadalajara, LNLJ, Public. Especial No. 1, El Grullo, Jalisco, Mexico and Contr. Univ. Wisconsin Herb. No. 9, Madison. 166 pp.
Vietmeyer, N.D. (1979). A wild relative may give corn perennial genes. Smithsonian 10(9): 68-76.
This Data Sheet was written by Ramón
Cuevas-Guzmán, Dr Bruce F. Benz and Enrique J. Jardel-Peláez (Universidad de
Guadalajara, Instituto Manantlán de Ecología y Conservación de la Biodiversidad, Apdo.
Postal 1-3933, Guadalajara, Jalisco C.P. 44100, Mexico) and Olga Herrera-MacBryde
(Smithsonian Institution, SI/MAB Program, S. Dillon Ripley Center, Suite 3123, Washington,
DC 20560-0705, U.S.A.).
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