STRUCTURE ARBOREAL OF THE DECIDUOS TROPICAL FOREST USED FOR THE EXTENSIVE CATTLE GRAZING IN THE NORTH OF THE SIERRA DE MANANTLAN, MEXICO. ANTAGONISM OF USES

Lázaro R. Sánchez-Velásquez*,**, Guadalupe Hernández-Vargas*, Mario A. Carranza-M.*, Ma. del Rosario Pineda-López*,**, Ramón Cuevas-G.* y Fernando Aragón-C*.


*Laboratorio de Ecología Aplicada
Instituto Manantlán de Ecología y Conservación de la Biodiversidad
Departamento de Ecología y Recursos Naturales
Centro Universitario de la Costa Sur, Universidad de Guadalajara
Independencia Nacional núm. 151, Autlán, Jalisco, 48900, México
**Instituto de Genética Forestal, Universidad Veracruzana,
Parque Ecológico La Haya, Carretera vieja a Coatepec,
Xalapa, Ver., 91000, México

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Abstract

Tropical deciduous forests are among the least studied forests in Mexico and the most diverse dry forests in the world. Extensive cattle ranching and changes in land use to pastures are important pressures for these forests, which are considered among the most threatened in the world. This paper analyzes the structure, species diversity and uses of tree species of the tropical deciduous forest found in the Northern portion of the Sierra de Manantlan Biosphere Reserve. Four areas of tropical deciduous forest used by cattle were selected. These correspond to: a 10 year old secondary vegetation corridor, two areas of 15 and 20 year old forest, and another one of approximately 30 years. Vegetation data were collected through a randomly point centered quadrant sampling and ethnobotanic data through open interviews. We conclude that: 1) over 80% of the tree species in the secondary deciduous tropical forest in Zenzontla have at least one use, 2) species diversity (Shannon-Wiener Index) in Zenzontla's deciduous tropical forests is higher than that of other vegetation types found in the Sierra de Manantlan, such as cloud forest, pine forest and pine-oak forest, 3) species diversity and use increase with time, 4) the number of individuals of forage species is less than the number of individuals of the group of species with other uses, and 5) size structure sugests that in the future non-forage species will be more dominant than forage species. Paradoxically, important areas of the deciduous tropical forest used for forage and other uses (mainly medicinal and food) are under pressure for substitution for pastures.

PKey words: Deciduous tropical forest, diversity, ethnobotany, cattle-grazing, Sierra de Manantlán, Mexico.

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