Phytosociology of a Seasonally Dry Tropical Forest in the State of Michoacán, Mexico

Abstract

Background: seasonally dry tropical forests are considered critical and important ecosystems because they harbor exceptional biological diversity. Mexico lacks sound phytosociological studies of Seasonally Dry Tropical Forest and Michoacán is no exception. The present study may be regarded the first phytosociological in most of the Mexican pacific coast where seasonally dry tropical forests occurs.
 Questions/Objective: We aimed at describing the representative plant associations of the seasonally dry tropical forest, distributed on western Michoacán and to provide a sintaxonomic classification framework based on the floristic differentiation of the recognized communities and highlight its phytocenotic diversity.
 Study site and dates: Estado de Michoacán; 20 years.
 Methods: A total of 82 phytosociological inventories were conducted. Data were submitted to multivariate two-way indicator species analyses to depict plant communities and their ecological affinities.
 Results: From its analysis and interpretation, nine plant groups were differentiated, of which all but one was given the rank of association, which are Lysilomo acapulcensis–Heliocarpetum terebinthinacei , Ceibo aesculifoliae–Lysilometum divaricatae , Caesalpinio platylobae-Cordietum elaeagnoidis , Cochlospermo vitifolii-Lueheetum candidae , Lysilomo divaricatae-Cordietum elaeagnoidis ; Stenocereo quevedonis-Cordietum selerianae , Guazumo ulmifoliae-Cordietum elaeagnoidis ¸ Lonchocarpo huetamoensis-Cordietum elaeagnoidis and the community of Spondias purpurea-Cochlospermum vitifolium. 
 Conclusions: Comparative floristic and structural profiles among plant communities permitted us to distinguish their bioclimatic relationships. Diagnostic species representative of all plant associations were selected and used for sintaxonomic nomenclature.  Plant associations were finally array along bioclimatic and altitudinal gradients and showed in arranged phytosociological tables. The plant association/community’descriptions permitted to compare structural physiognomy, floristic composition, ecological affinities, distribution patterns and bioclimatic liaison among them.