Tree species richness and diversity of the seasonally dry forest in Central Depression of Chiapas

Abstract

Tree diversity in the Central Depression of Chiapas was evaluated through 96 circular plots (0.1 ha each) distributed along to altitudinal range between 441 and 1740 m. Hierarchical cluster analysis helped to identify five plant associations; three of them corresponds to the tropical dry forests (TDF), and two Quercus forest. Regional richness included a total of 233 species, 152 genera and 57 botanical families. The contribution of local plots to the total diversity was highest in the TDF associations than in the Quercus forest associations. Species composition was dominated by individuals of late successional stages in the TDF (40-56%), while greatest contribution was secondary species in the Quercus forests (46-54%). Ordination showed a significant correlation plots with 10 of 12 climatic variables, which the average annual mean temperature of warmest month (r(2) = 0.74, P <0.001) and mean annual precipitation (r2(=) 0.85, P <0.001) were the most important. Although the Central Depression of Chiapas remains less than 2% of its forest cover, tree diversity is relatively high due to environmental heterogeneity which promotes species turnover at the regional level.