Floristic and structural heterogeneity of Schinopsis balansae (Anacardiaceae) forests in the southern Humid Chaco region

Abstract

At a regional scale, changes in tree and herbaceous cover relative to topographic variation have been observed in the landscape of Chaco region. Nonetheless, structural and floristic variations associated with topography are quite unknown at local scale. This study surveys the forests of Santafesinian Humid Chaco with special concern to the variation of structure and floristic composition along the topographic gradient. Twenty transects of 150 m each were used to determine frequency, density and DBH of tree and bush species. In short, 21 tree, 19 young tree and 16 bush species were registered. The tree species belonged to 18 families and 30 genera, and the richest family was Fabaceae with 11 species. In forest where the low topographic sites were dominant, frequency of young and adult trees were high and low, respectively. In contrast, richness and diversity indexes did not show changes along the same gradient. Results are discused in relation to regional ecological knowledge of S. balansae forests.