Diversification along environmental gradients and its implications for organismal responses to climate change

Environmental gradients are ubiquitous, yet we still lack a proper understanding of the often-nuanced organismal responses along them. This problem is compounded by the fact that usually several different environmental gradients act simultaneously in natural systems, so teasing apart which environmental factor is driving which phenotypic response(s) can be quite challenging. However, gaining a better understanding of organismal responses along environmental gradients will be beneficial also for our understanding of, and ability to more precisely predict, organismal responses to human-induced environmental change (in particular with respect to climate change). This proposed project aims to address these issues by studying phenotypic responses of several widespread livebearing fishes of the family Poeciliidae (with a special focus on Poecilia vivipara and the invasive guppy, Poecilia reticulata) along several environmental gradients across Brazil (including gradients of temperature, salinity, pH, oxygen availability, and land-use). The student will employ an integrative approach that combines environmental, behavioural (mate choice and boldness), morphological (body shape and colouration), physiological (thermal tolerance), life-history, and population-genetic data to identify shared (i.e., parallel) and unique responses of different species and population to these different environmental gradients. The project will involve field work and potential lab work in Brazil, potential lab work (population genetics) in China, and lab work at Royal Holloway, University of London. This project has the potential to significantly contribute to our understanding of biological diversification as well as how human-induced habitat alterations affect biodiversity. The student will be trained in various different cutting-edge methods of quantifying phenotypic and genetic diversity.