Vegetation of a tropical dry forest in a landscape with chronic disturbance: the case of the indigenous community of San Nicolás Zoyatlan (Guerrero, Mexico)

Background. Tropical dry forests (TDF) provide numerous environmental services to its residents; this has led them to be humanized landscapes subjected to chronic disturbance with a high risk of disappearing. Research question. To establish the relationship of vegetation structure and composition of a chronically disturbed TDF, with some environmental factors and the intensity of agricultural land use. Study site and period of research. Our study was conducted during six months (July through November) in the TDF of the community of San Nicolas Zoyatlan (Guerrero, Mexico); a territory with a history of over 500 years of agricultural use. This use has led to a complex mosaic of vegetation fragments. Methods. A selection of 36 fragments was studied to determine vegetation structure and composition as well as environmental factors. Representative plants from sampled areas were collected. Data gathered was explored with regression and multivariate statistical analysis techniques. Results. 59 families, 178 genera and 279 species were recorded. Species richness varied widely among fragments, in general with a low dominance and high turnover of species. Slope was the only factor that showed a solid relationship with vegetation variables. Three groups of fragments were established and the statistical differences between them were explained by the duration of fallow. The fragments with longer fallow period showed the best conditions in vegetation variables and 66.9% of the species were found in them. Conclusions. Composition and structure of vegetation were related to intensity of agricultural land use. Although there is a process of impoverishment, vegetation dynamics involving species of the Fabaceae, Asteraceae and Burseraceae families show a potential for their use in the environmental restoration of Zoyatlan. Antecedentes: Los bosques tropicales secos (BTS) aportan numerosos servicios ambientales a sus habitantes, esto los ha llevado a ser paisajes humanizados sujetos a disturbio crónico con riesgo de desaparecer. Pregunta: ¿Cuál es la relación de la composición y estructura de la vegetación de un BTS sujeto a disturbio crónico, con algunos factores del medio físico y la intensidad de uso agrícola del suelo? Sitio de estudio y fecha: El estudio se realizó en la comunidad de San Nicolás Zoyatlan (Guerrero, México) durante seis meses (junio-noviembre). Este territorio cuenta con más de 500 años de uso agropecuario, lo que ha propiciado un complejo mosaico de fra