Abstract

SANTANA, Gerardo et al. Preliminary analysis of the biodiversity and structure for tree and scrubs in the mountain cloud forest on the Transversal Volcanic System from Michoacán, Mexico. Rev. Mex. Biodiv. [online]. 2014, vol.85, n.4, pp.1104-1116. ISSN 2007-8706.  https://doi.org/10.7550/rmb.41519.

The objective of this study was to analyze the biodiversity and structure of Cloud Mountain Forest (CMF) located in the Trans Volcanic System in Michoacán (TVSM), Mexico, which is threatened by current land use changes. We sampled a variable number of 50 x 2 m transects depending on the total area in each of 11 CMF fragments. We found a total of 2 083 individuals representing 57 tree and shrub species. Results obtained with species abundance, Shannon Index, Similitude (Jaccard with 45% and Sorensen with 31%, as maxim values for both), normalized diameter, vertical structure and cover showed an important heterogeneity in the fragments but with floristic elements from CMF. Fifty percent of reported species had normalized diameters between 2.5-9.49 cm, and 13% had normalized diameters < 38 cm. Estimated Basal area ranged from 7.59 (fragment 3) to 114.4 m² ha^-1 (fragment 6). Styrax argenteus, Pinus pseudostrobus and Ternstroemia lineata were dominant in terms of the relative importance value in all CMF fragments sampled. We observed that CMF in the TVSM is confined to ravines, and that area of fragments reported by Inegi was overestimated. Comparisons between the occurrence of species in the CMF analyzed and in nearby and regional sites with the same ecosystem, showed a low similitude, with a higher dissimilitude the distance to the CMF we studied was larger.

Keywords : fragments; Shannon index; similitude; relative importance value; normalized diameter; vertical structure.