Resumen:
Abstract Background: The Sayula sub-basin located in the center-south of the state of Jalisco, presents a complex landscape made up of different plant communities along an altitude gradient. Despite the fact that there are different studies in the area, they have not addressed the distribution of the vegetation along this gradient, nor its bioclimatic interpretation. Questions: What is the bioclimatic diagnosis of the sub-basin? What are the bioclimatic belts and how are they linked to their corresponding natural potential vegetation? What are the floristic bioindicators of each bioclimate belt? Study species: Vascular plants, types of vegetation. Site and years of study: The Sayula sub-basin; 2017 to 2020. Methods: Literature review, field work, bioclimatic analysis and desk work. Results: The area belongs to the Tropical Macrobioclimate, recognizing the Tropical Xeric and Tropical Pluviseasonal bioclimates; the first includes the Semi-arid Thermotropical, Dry Thermotropical and Dry Mesotropical bioclimatic belts, and the second includes the Subhumid Mesotropical and Humid Mesotropical bioclimatic belts. The mentioned categories were worked on in a GIS obtaining a cartography that showed their spatial distribution. Likewise, the geobotanical information was synthesized in a representative vegetation chain and in tables that link the floristic, vegetational and bioclimatic information. Conclusions: The bioclimatic diagnosis allowed to establish the distribution of the bioclimatic belts as well as their relationship with the types of vegetation. The changes in terms of physiognomy, structure, composition and ecology of the vegetation belts are in line with the variations of the bioclimatic conditions along the altitudinal gradient.