Macroecologia do gênero Uca (Crustacea, Decapoda): padrões de diversidade, distribuição e respostas às mudanças climáticas globais

• Autor(a) principal: NABOUT, João Carlos
• Data de Publicação: 2009
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• dARK ID: ark:/38995/001300000cnrw
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tde/344
• topic: Caranguejo violinista, cienciometria, distribuição geográfica, modelo de distribuição de espécie, conservação de nicho, aquecimento global; Fiddler crabs, scientometric, geographic range, species distribution model, niche conservatism, global warming; CNPQ::CIENCIAS BIOLOGICAS

Macroecology of the genus Uca (Crustacea, Decapoda): Patterns of diversity, distribution and responses to global change. The genus Uca, composed by 97 species, has a worldwide distribution on coastal marine regions, mainly in tropical environments. Many researches have used the genus Uca as a model of study, although the actual scientific knowledge about this group is dispersed. Moreover, few studies have investigated its global and evolutive patterns. In this sense, considering that the genus Uca has no taxonomic problems (there is a consensus about its distribution and species identification), presents wide geographical distribution and has phylogenetic topologies, this group can be used as an excellent model to test macroecological and evolutionary hypotheses, and to discuss the effects of climate change on coastal organisms. The aim of this study was to detect trends and biases in scientific literature about the genus Uca, as well as to assess macroecological patterns (at a global scale) and to evaluate the influence of climate change on the geographical range size and species richness. Moreover, we associated the information generated to improve conservation strategies for species of the genus Uca. Considering our goals, we generated four papers in this thesis. Among the most prominent results, we observed that, the number of papers about the genus Uca indexed in Thomson ISI database, did not increase between 1991 and 2007, which may indicate the lack of interest of the scientific community on this taxonomic group. Moreover, the majority of the scientific production about the genus Uca came from institutions in the USA. The studies about the genus Uca were mainly characterized as population papers (which analyzes population attributes such as density, distribution and ecological interactions). The results of species accumulation curve demonstrated that the total number of Uca species currently know (97 described species) is substantially lower than the number predicted by the asymptote of the Gompertz model (134 species predicted), suggesting that new species need to be described. However, a new species of Uca is not described since 1987. Models were generated to explain the date of species description based on the body size, geographical range size, human influence and the type of habitat of each species. These models were selected using the Akaike Information Criteria (AIC). The best model among the candidate ones (explaining 37% of the total variance) was composed by variables representing the geographical range size of species, their body size and the human influence on them. In other words, large-bodied species and those widely distributed, mainly in regions with elevated human influence, were described earlier. In another paper of this thesis, we evaluated the levels of phylogenetic heritability of species of the genus Uca on their geographical range size, shape and position. If a strong phylogenetic signal of geographic range sizes exists between close related species, we can predict the unknown geographic range of species through the known geographic range of its relatives, which is useful for conservation purposes. However, the absence of phylogenetic signal was evidenced for this trait. On the other hand, there was a strong phylogenetic pattern considering the position of the range (mainly along longitudinal axis), probably due to mechanisms of vicariant allopatric speciation and to the geographical structure of the cladogenesis of the group. In the last paper, the impact of global changes on geographic range size of genus Uca were modeled, producing a comprehension about a poleward shift and elaborating maps of species richness based in two scenarios of global change. The models generated presented good performance, and predictions are that the species will probably have reduced the geographical range size and some species will be extinct (considering two scenarios until 2050), mainly in the tropical regions. Moreover, the range of species with midpoints in both hemispheres changed towards to poles in the future scenarios of climatic changes. Finally, the results of this set of papers highlighted the urgency of detailed studies for some species of Uca, and in some coastal marine regions (e.g. Indo-West Pacific) to evaluate the actual status of the distribution of species of the genus Uca and the real species richness of this genus. This is essential to generate local strategies aiming to minimize impacts of global change on coastal organism