Spatial Structure, Diversity, and Edaphic Factors of an Area of Amazonian Coast Vegetation in Brazil1

Abstract

This study intends to verify whether edaphic factors contribute to the structural arrangement of the woody restinga vegetation in the Northeast region of Brazil, and whether there is similarity between the restingas of the Amazonian and Northeast coasts. To sample the restinga vegetation of Maranhao State, we used the point-quarter method. In each quadrant, we collected soil samples to determine the chemical and physical variables. We built a matrix to correlate the soil variables with the species, using the canonical correspondence analysis, and used cluster analysis for the similarity. The analysis resulted in 32 species and 17 families. Astrocaryum vulgare, Protium heptaphyllum, Anacardium occidentale, Coccoloba latifolia, and Tilesia baccata presented higher importance value. The Shannon's diversity index was 2.9 nat.ind-1, and Pielou's equality was 0.8. The correlation analysis showed that only Chioccoca alba and Mouriri guianensis presented positive correlation with magnesium, organic matter, sum of bases, and base saturation. Regarding similarity, the flora of the restinga in the present study resembles the restinga of Alcântara, in Maranhao State, and an area of Ceara State. Finally, we assert that such studies of the Northeast coastal vegetation constitute an important tool to assist in the development of strategies for biodiversity conservation.