Estudos fitogeográficos no gênero Guzmania Ruiz & Pav. (Bromeliaceae: Tillandsioideae)

Abstract

The geographical distribution of taxa is determined by its capability of dispersion together with a range of abiotic (e.g. temperature, light amount and humidity) and biotic factors (e.g. ecological interactions like competition and predation). Bromeliaceae is the second great family of vascular epiphytes, contributing with the total richness of species in Neotropical forests and with the greater diversity and endemism in high altitudes. This work aims to answer the following questions: i) What are the distribution patterns of Guzmania Ruiz & Pav. species and which environmental filters maintain this distribution? ii) Which areas present greater richness and diversity of species? iii) Taking into account the premisses offered by the predictive modeling, which is the potential area of distribution of Guzmania species?Data of geographical distribution of Guzmania were obtained at Centro de Referências de Informações Ambientais - CRIA - and later the maps of geographical distribution were produced using DIVA-GIS 7.5 program. The Neotropical region was divided into 10 phytogeographic areas. The species were classified into two distribution patterns, large and restrict, where the former could be continuous or disjunct, and the phytogeographic patterns were described. Shannon index (H`) was used to determine the richness and diversity patterns and to similarity analysis (UPGMA) it was constructed a binary matrix with data concerning presence =1 and absence =0 aiming to determine the flower blocks of species presenting similar patterns. Based on this matrix it was conducted a PAE (Parcimony Analysis of Endemicity) analysis, which classifies areas or localities with analogous taxa. Modelling of predictive distribution was performed only to species occurring at ombrofila forest remnants in Ceará state (Humid Mountains). The studied Guzmania species presented a large distribution pattern at Neotropical region with disjunctions at Brazilian Northeast into the phytogeographic domains of Caribbean, Amazon, Guayana, Andes-Patagonia and Chaco. The greater diversity area of the gender was at Andes region, followed by Amazon, Central America, Guayana Shield and Humid Mountains of Ceará. Similarity analysis (UPGMA) based on species distribution revealed the formation of three flower blocks. The modeling of potential distribution predicts a drastically reduction in the areas where the species are found, specially at Humid Mountains.