Resumen

ZAMORA CRESCENCIO, Pedro; GARCIA GIL, Gerardo; FLORES GUIDO, José Salvador  y  ORTIZ, Juan Javier. Structure and floristic composition of the tropical medium subdeciduous forest of southern Yucatan, Mexico. Polibotánica [online]. 2008, n.26, pp.39-66. ISSN 1405-2768.

Nine sites totaling 1000 m² were selected for testing in the tropical medium subdeciduous forest of southern Yucatan. The woody species encountered were identified and recorded. The diameter of each specimen at breast height (DAP) and the height of all individuals with DAP > 3 cm were measured. The structure of each site was described based on relative values of density, frequency and dominance as well as the distribution of height and diameter classes. Species diversity for each site was estimated using the Shannon Wiener Index, and the floristic similarity between sites was evaluated using the Morisita Index. A total of 128 species and 3 847 individuals > 3 cm were recorded. The families best represented were Fabaceae (13 genera, 14 species) and Rubiaceae (6 genera, 10 species). The genera with the largest number of species were Diospyros and Lonchocarpus. The number of species per site varied from 36 to 58, the majority of sites containing around 47 to 48 species. Bursera simaruba, Croton reflexifolius, Diospyros cuneata and Gymnanthes lucida presented the greatest density per hectare. The most important species in the upper stratum (> 14 m) were Lysiloma latisiliquum, Gymnanthes lucida, Manilkara zapota, Thouinia paucidentata, Vitex gaumeri, and Bursera simaruba among others. The diameter classes demonstrated that there existed sufficient individuals for forest regeneration. The species that showed the greatest importance values were Gymnanthes lucida, Lysiloma latisiliquum, Bursera simaruba and Diospyros cuneata. The diversity values showed that site 7 was the tallest and site 5 the lowest with 3.5. In accordance with the index of similarity sites 3 and 4 were most similar to one another, whereas sites 5 and 9 demonstrated the greatest floristic disimilarity in comparison to the rest.