Checklist e Análise de Similaridade da Flora de Licófitas e Samambaias do Rio Grande do Norte
Lycophytes and ferns are seedless vascular plants, dispersed by spores. A striking feature is the ability of these plants to settle in areas with different morphoclimatic conditions, with greater richness in regions with high humidity. The Atlantic Forest domain is a great center of richness and end...
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| Formato: | bachelorThesis |
| Idioma: | pt_BR |
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Universidade Federal do Rio Grande do Norte
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| Endereço do item: | https://repositorio.ufrn.br/handle/123456789/37317 |
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| Resumo: | Lycophytes and ferns are seedless vascular plants, dispersed by spores. A striking feature is the ability of these plants to settle in areas with different morphoclimatic conditions, with greater richness in regions with high humidity. The Atlantic Forest domain is a great center of richness and endemism of the species of these groups in the world, but there was great loss of biodiversity due to the historical exploitation of the domain, leaving sparse remnants. In the Caatinga domain there is also the registration of species of lycophytes and ferns, because of the easy dispersion and adaptation to dry periods. But the domain is heavily exploited and one of the least protected in Brazil, which is a major threat to its biodiversity. Rio Grande do Norte is one of the states that is less known about its flora, even less about neglected groups such as lycophytes and ferns, being indispensable more studies with the flora for conservation. With this, the aim of this study is to develop a checklist of the species of lycophytes and ferns and define their distribution patterns in Rio Grande do Norte (RN) and compare areas of the Caatinga and Atlantic Forest in the state with other areas north of the São Francisco River. Occurrence data of the species in Alagoas, Ceará, Paraíba, Pernambuco and Rio Grande do Norte were obtained in virtual herbaria. The identification and correction of the names of the species were performed, and from this database of the RN was elaborated a list of species and distribution patterns by the state. A presence and absence matrix was constructed from selected areas, which was used in similarity analyses and NMDS (Nonmetric Dimensional Scaling), also using environmental variables. The Mantel test was performed with geographical and floristic distances and a linear regression of richness as a function of the extent of the study áreas. In the RN there is the record of 61 species of lycophytes and ferns, an increase of about 179% based on the most recent survey for the state. Four patterns of distribution of the species were defined. The similarity analysis brought the areas together in four groups, two in the Caatinga (A and B) and two in the Atlantic Forest (C and D). All groups follow established and proposed ecological standards for the region. In the NMDS, the same clusters of similarity analysis were observed and the environmental variables condition the clusters well. The Mantel test gave the expected result, since these groups of plants have easy dispersion, not relating the floristic distances with the geographic distances. Linear regression resulted in a negative correlation between richness and area extents. The present work presents a great advance in the knowledge of the flora of lycophytes and ferns of Rio Grande do Norte. With the similarity and NMDS analyses it is possible to better understand the occurrence of the species of the groups in the Domains of Caatinga and Atlantic Forest. |
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