Structure and diversity of a shrub Helietta parvifolia (A. Gray ex Hemsl.) Benth.

Abstract

Helietta parvifolia is a species of economic importance in Northern Mexico, being a potential source of wood and firewood for several uses. The objective of the study was to evaluate the structure and diversity of a mature H. parvifolia scrub in Northwest Mexico. Vegetation diversity was determined by establishing 20 sampling sites of 10 × 10 m each (2000 m in total), where the normal and crown diameter of all trees and shrubs with a diameter ≥ 3 cm were recorded. The Margalef, Shannon and Pretzsch indexes were calculated for richness, species diversity and vertical structure, respectively. Eleven tree and shrub species were found, distributed in nine genera and six families. The Fabaceae family had the highest number of taxa (five), while the remaining families had only one species. Three of them concentrated 82.59 % of the importance value index values (IVI): Helietta parvifolia, Cordia boissieri and Havardia pallens, with 53 %, 15.44 % and 14.15%, respectively. The abundance of individuals of small diameter classes suggests the existence of an active regeneration state.