Characterization and floristic structure of a plant functional group of tamaulipan thornscrub

Abstract

The structure, diversity and density of vegetation are important for the characterization of ecosystems. In the present study was characterized the structure and diversity of succulent species, trees and shrubs in area of tamaulipan thornscrub of the northeast of Mexico. Was established 70 sampling sites 10 x 10 m (100 m²), where was perform a census of all trees and shrubs (d _{0.10 m} > 5cm), including succulent plants. Were made to each individual measurements of diameter of canopy. For each specie was obtained the importance value index (IVI) calculated starting of three variables, abundance according with the number of trees per hectare (n ha-1) dominance across of the coverage of the canopy area, and frequency with base in its presence in the sites of sampling. Also was calculated the Shannon index (H´) and Margalef index ( ^DMg ). In total were registered 67 species, 55 genres and 25 families. This plant group present a density of 3,313 ind ha-1 and the coverage of the canopy area of 16,671 m²/ha-1. Acacia rigidula was the one that obtained the major values of importance with 8.04% of ^IVIrel . The curve of range/abundance of species adjusted to a log-normal function, characteristic of the associations of ripe plant. For the Margalef Index was obtained a value of ^DMg =8.14, this indicates a high richness of species. With this are provided quantitative elements of the arboreal vegetation, shrubby and succulent of a vegetable plant functional group of the tamaulipan thornscrub, indicating that this type of vegetation presents a high diversity and richness of species compared to other ripe plant associations of shrub.