Ecological opportunity and the origins of novel biodiversity

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Our long-term research program addresses fundamental questions about how biodiversity in the form of resource polymorphism arises within single populations of fishes composed of alternate ecotypes that live in different lake habitats. Our NSERC-funded research program has contributed empirically and conceptually to the theory of adaptive divergence, the central framework used to understand biodiversity formation. We identify and test factors that regulate the formation of specialized ecotypes, and have expanded theory by including a role for phenotypic plasticity in specialization and its influence on adaptive divergence. Long-term experience with resource polymorphism in pumpkinseed sunfish since 1993 (13 articles) and other fishes (10 articles) uniquely positions us to investigate causal factors that regulate how multiple ecotypes evolve and how this may be converted into new species. This work is important not just in its relation to biodiversity formation, but also because diversity within populations is rarely considered in the contexts of ecological function, management and conservation, or its capacity to buffer populations from adverse effects of environmental change. Long-term studies in natural populations provide the vital ecological understanding required to address novel questions about diversification. The key problem for the adaptive divergence of co-occurring ecotypes is that mating and sexual recombination break down combinations of useful genes favored by selection for specializing in different habitats, preventing the formation of genetically distinct ecotypes. Yet these ecotypes are common in Canada's fishes, providing us with the opportunity to study biodiversity formation processes at their earliest stages. Our long-term objectives focus on understanding the processes that generate selection and that allow individuals to mate assortatively. Over the next 5 years, we will study how dispersal influences whether ecotypes encounter and mate with their own or a different ecotype, the role competition plays in generating selection for ecotype specialization, and how the cognitive challenges of different lake habitats influence brain size and behaviour of fish in different habitats. This work will make novel contributions to our understanding of divergence processes in a natural context. Importantly, our field and lab-based research comprises an essential part of my HQP training program. Over the last 6 years, our research has supported the training of 27 HQP, that generated 10 publications (plus 1 in press and 2 resubmitted after revision) and more than 31 HQP conference presentations. Over the next 5 years, HQP will gain experience in a wide array of field ecological and lab methods involving various life stages of fishes and considerable analytical training. A total of 3 PhD, 1 MSc and more than 20 undergraduates will benefit from the research enabled by this Discovery request.