Shrnutí: | Oaxaca is the Mexican state that presents the highest level of biodiversity. The number of Protected Natural Areas (PNA) in this region is minimal, and they represent one important type of government conservation strategy; others include the recently created Areas Voluntarily Devoted to Conservation (AVDC), as well as Common Use Areas (CUA) that are managed freely by local users. Trends in deforestation compel us to question “what processes are occurring in forested areas?” This study proposes a comparison of the structure and composition of woody plants (as organisms that define terrestrial ecosystems) among the three aforementioned types of protected areas within two different regions of Oaxaca, Mexico: the Mixteca region comprising oak forest (OF) and Valles Centrales consisting of dry tropical deciduous forest (DTDF). In each area, 15 quadrats of 100 m2 (plots) were established along a transect where individual trees with the diameter at breast height ≥ 2.5 cm were recorded. The similitude among areas of each region was evaluated using the Jaccard Index (floristic data from plots). Diversity, Relative Importance Value (RIV), density, frequency and basal area were estimated. In the DTDF, 28 species belonging to 25 genera and 13 families were recorded; similitude formed two groups; density differed significantly. In the comprising oak forest, 51 species were recorded, belonging to 37 genera and 24 families; similitude formed two groups; richness presented statistically significant differences. Forest structure is similar between Protected Natural Areas and Common Use Areas in the Valles Centrales region. In the Mixteca region, the Common Use Area was the most diverse area.
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