Differences of vegetation structure and diversity of a forest in an altitudinal gradient of the Sierra La Laguna Biosphere Reserve, Mexico

Background: The Sierra La Laguna Biosphere Reserve is located which is considered an “island of vegetation” within an arid environment. Considering that this protected natural area has an altitudinal gradient that ranges from 500 to 2,100 meters above sea level. Hypothesis: Higher altitudinal gradient decreases abundance, basal area and diversity of plant species. Studied species and data description: The data analyzed in this study included the structural variables of abundance (N ha -1 ), basal area (m 2 ha -1 ) and diversity (alfa and beta) of arborous species in areas with different elevations. Study site and dates: This study was carried out in four localities of the tropical deciduous forest and broadleaved forest. In the spring of 2016. Methods: Five circular sampling plots of 500 m 2 for arborous vegetation and 1m 2 for herbaceous vegetation were established in every vegetation community, resulting in 20 sampling plots. Results: Sixteen families, 22 genera and 22 vascular plant species were recorded. The most diverse family was Fabacea with four species followed by Cactaceae with three species. The abundance, dominance and diversity of vegetation species did not show any decrease (or increase) tendency of values as the altitudinal gradient augmented. Conclusions: The hypothesis is rejected because abundance, dominance and diversity of vegetation species do not show any decrease or increase tendency as the altitudinal gradient augmented. The vegetation communities showed a high similarity in the composition of species.