Florística e fitossociologia na Floresta Nacional Contendas do Sincorá, Bahia

Abstract

Considered the only biome exclusively Brazilian, the Caatinga vegetation covers 844.453 Km² of northeastern Brazil, being the main vegetation of the state of Bahia. The present work was carried out in the Contendas do Sincorá National Forest (FLONA-CS), located in the municipality of Contendas do Sincorá- Ba, with the objective of contributing on conservation units for this vegetation. The first chapter brings contributions and enlarges the data on the flora of FLONA - CS and its degree of conservation, based on a floristic inventory carried out with visits of duration of five days between the years of 2014 to 2017. The method used was collecting in random tracks seeking to cover the largest possible territory. 275 species distributed in 160 genera and 51 families were registered. A total of 113 endemic species from Brazil were identified, 33 endemic to the Northeast, 17 endemic to Bahia, 40 endemic to the Caatinga vegetation, 55 endemic to the Caatinga Phytogeographical Domain, among them some species are in danger of extinction: Handroanthus spongiosus (Bignoniaceae) and Espostoopsis dybowskii (Cactaceae). Two species were characterized as almost endangered: Amburana cearensis (Fabaceae) and Simira gardneriana (Rubiaceae), and in the category of vulnerable species Pereskia aureiflora (Cactaceae). The second chapter provides information on the structure and relationship of vegetation to the soil, randomly allocating 40 plots of 20X10m, where all individuals with DAS (soil height diameter) with 3 cm or more were sampled. In the area were sampled 3,710 individuals, distributed in 31 families, 67 genera and 103 species. According to the IVI (Importance Value Index), the most important families in the survey were Euphorbiaceae, Fabaceae, Bignoniaceae, Malvaceae, Cactaceae and Anacardiaceae. The species with the highest IVI were Croton heliotropiifolius, Handroanthus spongiosus, Jatropha sp., Schinopsis brasiliensis, Anadenanthera colubrina, Erythroxylum sp. 3, Luehea divaricata, Mimosa verrucosa, Myracrodruon urundeuva. Colicodendron yco and Bauhinia brevipes. The physical and chemical analyzes of the soil observed little or almost no influence directly linked to the distribution of the species. Being a heterogeneous soil both in relation to its physical and chemical composition.