XVI International Botanical Congess

Habitat preference associated to water availability was assesed at Chamela, Jalisco, Mexico. At 615 10 X 10m quadrats along three small watersheds, all trees with DBH > 5 cm were identified, and four environmental variables were considered: i) landform and ii) slope, related to water runoff, iii) total annual insulation, related to evapotranspiration, and iv) soil water retention capacity. Thirty of the 138 species were selected as they accounted for more than 80% of trees. Relationship between abundance and the three continuous variables were regressed. Landform preference was tested with Chi-square. All 30 species showed habitat preference for at least one of the variables. Relevance for maintainance of diversity in tropical dry forests is discussed.