Fabaceae Lindl. in the Chapada do Araripe, Northeast Brazil

Abstract

The Brazilian plateau known as Chapada do Araripe is home to several types of vegetation and a diversity of native species. This plateau is located among the Brazilian states of Ceará, Pernambuco, and Piauí, in the Northeast region. This study consisted of a floristic inventory of Fabaceae species prevailing in different environments of the mentioned plateau. Monthly botanical expeditions were performed from October 2021 to November 2022; these occurred at previously selected sites. The plant collection, herborization, and identification of the species were carried out according to the specialized literature, and the specimens were deposited in the Herbário Caririense Dárdano de Andrade-Lima (HCDAL). A total of 194 species, 11 infraspecific taxa, and 81 genera belonging to five subfamilies were listed. These numbers represented approximately 32% of the diversity of Fabaceae recorded in Brazil, and an increase of approximately 115% in the number of species previously recorded in the Chapada do Araripe. The most diverse subfamilies were Caesalpinioideae and Papilionoideae, with 90 and 89 species, respectively. The most representative genera were Senna (19 spp.), Chamaecrista (15 spp.), and Mimosa (14 spp.). Thirteen species and three varieties were new records in Ceará state. The predominant growth habit was tree type, recorded in 44% of the species (86), and the main habitats were Steppe Savannah, Savannah, and Wooded Steppe Savannah. Thirteen species are endemic to the Caatinga phytogeographic domain: Copaifera arenicola, Copaifera cearensis, Hymenaea cangaceira, Cenostigma microphyllum, Mimosa caesalpiniifolia, Mimosa misera, Parapiptadenia zehntneri, Pithecellobium diversifolium, Senna cearensis, Senna gardneri, Senna lechriosperma, Crotalaria holosericea e Luetzelburgia bahiensis. Regarding the status of species protection and conservation, most are in Least Concern status (48.8%), four are Near Threatened (Hymenaea cangaceira, Pterogyne nitens, Dalbergia cearensis, Parapiptadenia zehntneri), two species are in Vulnerable status (Melanoxylon brauna and Senegalia cearensis), one species did not have enough data for assessment (Copaifera cearensis), and one is Endangered (Amburana cearensis). The findings of the present study can support conservation strategies, and ecological and phytosociological studies, among others. Also, it can be used for planning and promoting environmental education. Such information is valuable for the conservation of biodiversity and sustainable management of natural resources of the Chapada do Araripe.