Resgate evolutivo e adaptação às mudanças climáticas ao longo do Pleistoceno

• Autor(a) principal: Barbosa, Igor Lucien Bione Dardenne
• Data de Publicação: 2020
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/10459
• topic: Bison bison; Paleoecologia; Conservação de nicho; Resgate evolutivo; Modelos de nicho ecológico; Sobreposição de nicho; Modelos eco-evolutivos; Paleoecology; Niche conservatism; Evolutionary rescue; Ecological niche models; Niche overlap; Eco-evolutionary models; CIENCIAS BIOLOGICAS::ECOLOGIA

The world has undergone several climate change events throughout history. Understanding the responses of extant species that underwent these changes is a way to access the strategies used by them on dealing with these changes. Overall, species tend to respond to climate change by dispersing to areas that remain climatically suitable, adapting to the change or becoming extinct. Dispersion to suitable areas is the answer commonly implemented by species and is related to the climatic niche conservatism. Species can also adapt to new climatic conditions through what has been called "evolutionary rescue". In this context, we have Bison bison, a large mammal species, that is well represented in the fossil record and managed to survive the different climatic events that occurred in the past. Here we used an eco-evolutionary approach, combining ecological niche models, niche overlapping methods and evolutionary models, to investigate the different types of responses adopted by Bison bison throughout the transition between the Pleistocene and Holocene to date. Our results showed a pattern of niche conservatism. The species had suitable areas further south of North America, which eventually moved north, following their climatic preferences. Niche overlap methods also indicated that over time the specie's niches tend to become more similar, with values greater than 0.5 for the vast majority of the analyzed intervals. However, despite the niche conservatism pattern, there were points of occurrence outside the climatic envelopes. The evolutionary models showed very low evolutionary rates to these points. When analyzed in the sense of their probability of being rescued, these points proved to be evolutionary viable within the considered parameters. The consistent pattern of niche conservatism and the great adaptive potential shows that, in the analyzed time interval, the species combined different types of strategies that allowed it to persist over time. The framework purposed here allows scientists to systematically analyze the historical dynamics of species distribution as well as its adaptive potential, and can potentially be used in future studies to access several questions in Paleoecology.