Padrões de variação de tamanho corporal e de distribuição geográfica são métodos-dependente em serpentes viperídeas do Novo Mundo

• Autor(a) principal: Caten, Cleber Ten
• Data de Publicação: 2018
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/8330
• topic: Regra de Bergmann; Regra de Rapoport; Viperideos do Novo Mundo; Bergmann’s rule; Rapoport’s rule; New World Pit vipers; CIENCIAS BIOLOGICAS::ECOLOGIA

Traditionally, ecologists and biogeographers have been interested in ecogeographical patterns with increasing demand over the last years. Bergmann´s and Rapoport´s rules are two of the most debated ecogeographical patterns, which propose increasing in species body size and range size, respectively, with latitudes. However, whether such rules widely apply to reptiles remains unclear. Moreover, there might be uncertainty regarding the method used to obtain species geographical range that might change our perception of such patterns. Here we tested different hypotheses regarding Bergmann’s and Rapoport’s rules using the New World Pit vipers (Viperidae: Crotalinae) as biological model, as well as analyzed the robustness of different methods to obtain species geographical range and evaluated both ecogeographical patterns using different approaches. We gathered occurrence data for the 136 Crotalinae species and generated geographical ranges by building polygons from Alpha Hull method and Ecological Niche Modelling. We assessed both rules using a ‘cross-species’ and an ‘assemblage’ approach. The former considers each species as an independent data, whereas the latter consider each assemblage (i.e. a grid cell) to be an independent data. We used Phylogenetic Least Squares (PGLS) and Generalized Least Squares (GLS) to evaluate the cross-species and the assemblage pattern, respectively. The former considers the phylogenetic independence of the data as the latter the geographic autocorrelation and both provide unbiased coefficients and significance levels. Our results show that Bergmann’s rule did not occur in the cross-species level, whereas it was statistically significant in the assemblage level regardless of the method used to obtain range size. We found support for Rapoport’s rule in the cross-species level regardless of the method used to generate range size. Meanwhile, the assemblage analysis was not robust methodologically, revealing different ecogeographical patterns depending on the method used to generate species geographical range. Our findings point that there are inconsistences between the patterns observed in the cross-species and the assemblage analysis, which could indicate that different processes producing these patterns in the cross-species and assemblage levels. Finally, our results highlight that this sensibility is especially evident in Rapoport’s rule assemblage analysis and that when evaluating this pattern in assemblage level the method that will be used to obtain species geographical range should be carefully chosen.