Do edaphic aspects alter vegetation structures in the Brazilian restinga?

The vegetation of the Brazilian restinga (coastal woodland) presents a variety of species and different characteristics,
encompassing fields, fruit groves and forests on quartzarenic neosols. We hypothesised that the structure of the
restinga landscape along the coast of the state of Piauí is influenced by edaphic factors and presents a pattern similar
to that of other northeastern restingas. We evaluated three restingas in Piauí, using the quarter method to determine
their structure. Composite soil samples were collected to determine their chemical and physical properties. Edaphic
variables were correlated with plant species by canonical correspondence analysis (CCA). Phytosociological data for all
three areas indicated regenerating vegetation comprising several small individuals, 82.5% of which showed a diameter
at ground level ≤ 13 cm. We also observed considerable tillering. In two of the areas, there was a predominance of
Fabaceae species, such as Caesalpinia pyramidalis and Copaifera martii. Although the structural characteristics of the
restingas studied were similar to those of other northeastern restingas, the former showed lower Shannon diversity
indices (2.18-2.44). The CCA indicated that species distribution was influenced by edaphic factors such as pH, aluminium content and amount of organic matter. The restingas studied were similar to others along the Brazilian coast.