CORRELATION BETWEEN SOIL VARIABLES AND HERBAC-SHRUB SPECIES IN REVEGETATION OF DUNES IN THE NORTHERN COAST OF THE PARAÍBA STATE - BRAZIL

Abstract

This work analysed the floristic and phytosociologycal occurrence of the secondary vegetation established on seven tailing dune (irrigated or non-irrigated) areas, and the interactions between the composition of this vegetation and physical, chemical, biochemical and microbiological soil traits. Both the floristic composition and structure (value of cover and frequency) of the plant community which formed upon dunes were recorded in forty, 3 x 3m plots. From the environmental variables of soil and distribution data of the species, the indirect analysis of the gradients was proceeded, yielding ordination diagrams of the plots, species and environmental variables (by canonical correspondence analysis, CCA). A total of 96 herb-shrub species belonging to 33 families was identified on recovering dune and “tabuleiro”. A greater number of species and families occurred in the irrigated dune areas. In dunes areas with three, five and seven years without irrigation, a higher cover value of Paspalum maritimum, Rhynchelytrum repens and Digitaria horizontalis was observed. The CCA separated the ‘tabuleiro’ and dune vegetation plots with one year from the other sites, while the dune vegetation of three, five and seven year of age irrigated or not, proved spread and did not point out the existence of a succession gradient in terms of soil variables and irrigation. The investigated sites, even those deeply disturbed, maintained a fungal community, favoring the evolution of an ecosystem, possessing a high number of arbuscular mycorrhizal spores (MA’s), this was particularly true in the five years old dune areas without irrigation.