Padrões espaciais e determinantes da diversidade taxonômica, filogenética e funcional de plantas na restinga brasileira

• Autor(a) principal: Oliveira, Eduardo Vinícius da Silva
• Data de Publicação: 2021
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da UFS
• Texto Completo: https://ri.ufs.br/jspui/handle/riufs/14822
• topic: Diversidade biológica; Ecossistemas; Biologia - Classificação; Biologia costeira; Restingas; Knowledge shortfalls; Community assembly; Water constraints; Historical dispersion; Species pools; CIENCIAS BIOLOGICAS::ECOLOGIA

Among the consequences of the interactions of organisms with the environment are several patterns of coexistence of multiple distinct organisms in space or patterns of communities. Of these patterns, those related to how many and which organisms compose these communities remain under debate. These two issues are expressed in terms of species diversity and composition. Historically, these studies have emphasized division by spatial scales, particularly locally within the community – or alpha diversity – and between communities – or beta diversity. Recently, studies on these patterns have contemplated different aspects of biodiversity, beyond to the traditional approach based on taxonomy, but including their evolutionary relationships and their characteristics, that is, phylogenetic and functional aspects. However, there is still no consensus on their causes, specifically when they involve specific biological groups in specific environmental contexts, either because of their inherent complexity or because of the systematic scarcity of information about the species. This is the case of plants in tropical coastal environments, such as Restinga vegetation. In this study, challenging different types of information gaps about coastal plant species in Brazil, we investigate the spatial patterns and processes involved in the diversity and composition of these communities. In the first chapter, after considering the level of knowledge regarding plant sampling efforts, we investigated geographic patterns and tested different ecological hypotheses for variation in species richness. Our results revealed that despite knowledge gaps in more than 3/4 of the area, we found that species richness appears to be best explained by habitat heterogeneity, soil properties and water constraints. In the second chapter, we investigate the compositional patterns, evaluating assembly rules of the functional and phylogenetic structure patterns of the assemblages and the role of different environmental predictors. We show that, under greater water constraint, assemblages with species functionally similar and pre-adapted to Restinga conditions predominated. In sites associated with megadiverse rainforest ecosystems, the composition of the assemblages tends to more stochastic arrangements or with more distinct species in terms of their phenotypic and phylogenetic similarities. Water constraints were the main responsible for causing variation in these patterns of phylogenetic and functional structure. Finally, in the third chapter, we evaluate the relative contribution of the beta diversity components, i.e., turnover and nestedness, if these processes result from stochastic dispersion and which environmental predictors account for the dissimilarity patterns between assemblages. Patterns of taxonomic beta diversity do not correspond to stochastic dynamics, unlike phylogenetic and functional dissimilarity patterns. Water availability appears to be the determining factor in the spatial patterns of dissimilarity of the three aspects of beta diversity. The three perspectives evaluated revealed a complex pattern of interaction between regional patterns of diversity – where adjacent ecosystems that are sources of species contributed in different ways – and different degrees of restriction on species colonization due to environmental factors, specifically water availability. Our study was the first to describe the patterns and drivers of Restinga plant assemblages, contributing to the understanding of the origin and dynamics of this ecosystem and patterns in contexts and specific environmental systems. Despite gaps in biodiversity information, these limitations should not impede our ability to investigate these patterns at a geographic scale.