Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Accueil du site → Master → Brésil → Floristic study of a rochy outcrop at the environment protected area (apa) in the region of Cariri, State of Paraíba : richness, similarity and phytogeography

Universidade Estadual da Paraíba (UEPB) 2011

Floristic study of a rochy outcrop at the environment protected area (apa) in the region of Cariri, State of Paraíba : richness, similarity and phytogeography

Machado Filho, Hermes de Oliveira

Titre : Floristic study of a rochy outcrop at the environment protected area (apa) in the region of Cariri, State of Paraíba : richness, similarity and phytogeography

Composição florística de um ambiente rochoso da Área de Proteção Ambiental (APA) do Cariri, Paraíba : diversidade, riqueza e fitogeografia

Auteur : Machado Filho, Hermes de Oliveira

Université de soutenance : Universidade Estadual da Paraíba (UEPB)

Grade : Mestrado em Ecologia e Conservação 2011

Résumé
A rocky environments is a geomorphological shape which holds richness and specific endemism, even more, taking as reference semiarid conditions. Based on this perspective, this work aims to present the study of the floristic composition, emphasizing diversity, richness, and biogeographic patterns on a rocky outcrop, in the Environment Protection Area (APA), in the region of Cariri , located between the municipalities of Boa Vista and Cabaceiras, state of Paraiba (Northeast from Brazil). Field works have been done aiming the collecting of botanic material and observations in loco , over all the area extension, in the period between March 2010 and October 2010. Based on APG (Angiosperm Phylogeny Group) III, the checklist was elaborated to the studied area. Moreover, it was made a binary matrix of presence/absence of the registered species, in order to detect the similarity of the flora together to other areas, focusing mainly floras installed in the Brazilian semiarid zone. It was also made another binary matrix to verify the geographic distribution patterns of its species and established relations of this flora together to other South American biogeographical provinces. The analyses of geographic distribution have been supported in searches to specialized bibliography and data basis of neotropical species as : taxonomic papers, local floras, W3 Tropicos (Missouri Botanical Garden) and the species list on line of the Brazilian flora. In the studied area, 127 species were registered, distributed in 53 flowering plant families. Fabaceae was the most representative, with 14 species, result in agreement with the vast majority of the floristic studies taken in the Brazilian semiarid zones. Other families highlighted in number of species were : Convolvulaceae, Malvaceae and Euphorbiaceae, with nine species each ; Asteraceae, with seven ; Cactaceae, with six ; Bromeliaceae, with five and Rubiaceae, with six species. The herbaceous and subshrub components were predominant over the others in the local flora. The similarity analyzes showed that the flora on rocky environments trends to form specific blocks, when compared to other formations. The species presented basically three patterns of geographic distribution : ample-continuous or tropical (CA), with 44% of total species ; restrictcontinuous or pre-Andine sub-tropical (CR), with 34% and restrict (R), corresponding to the Caatinga/Savannah , with 22%. The analyzes of the flora similarity in the South American region has shown the close relation between floras in Caatinga and Savannah pattern, with level of meaning = 98,2 (Jaccard index). This result points to the existence, nowadays, of a floristic corridor among these vegetation types, this aspect probably features the Arc-Pleistocenic relict, when the Caatinga became a forest reduct and turning a floristic connection possible with the most diverse vegetation types, mainly with those which make the xeric corridor in South America. The obtained data through this study point to the existence of a diversified flora, showing biogeographic patterns closely related to the species distribution, several of them being endemic to Caatinga vegetation, as Allamanda blanchetti DC. (Apocynaceae). For all those reasons, the area dealt here, comes out as a center of great importance for local fauna and flora maintenance, as well as for the micro-region in the Cariri, Paraiba state, where it is located.

Mots Clés : Flora Brasileira Biogeografia Semiárido Brazilian Flora Biogeography Semiarid

Présentation

Version intégrale (2,06 Mb)

Page publiée le 26 juillet 2017