Adapting to environmental change: driving factors and the persistence of small populations

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Global environmental changes such as climate change and habitat fragmentation are leading to diminishing population sizes and the isolation of populations within many species. For many populations, extinction is likely if they cannot respond to such changes via adaptive evolution or phenotypic plasticity. Which populations will be able to adapt? How much environmental change can populations withstand and still persist? What are the strongest predictors for responding to environmental change? And will sufficient adaptation occur to retain the services that populations deliver to humankind? A number of key factors are predicted to decrease the ability of populations to respond to changing environmental conditions, including (i) reduced population size and genetic diversity, (ii) diminished phenotypic plasticity, (iii) a history without exposure to environmental fluctuations or stress, (iv) a higher degree of environmental change, and (v) the inability to (at least partially) overcome deleterious inbreeding effects associated with small population size. However, many of these predictions arguably are being accepted without receiving much strong testing in wild populations. My research program represents an original and integrative empirical investigation into how multiple factors affect responses to environmental change in vertebrate populations, specifically: population size, standing genetic variation, the extent of phenotypic plasticity that a population expresses, the extent of habitat variability or environmental change that a population experiences, and the effectiveness of overcoming inbreeding effects through purging. To test theoretical predictions, my research team will extend innovative, multi-year demographic, genetic, and genomic studies of 20 trout populations (inhabiting Cape Race, Newfoundland) in conjunction with a large series of population transplant experiments to new, natural environments. This proposed research will result in the training of nine highly qualified personnel (2PhD, 2MSc and 5 undergraduate student research theses) and a number of volunteers, in an interdisciplinary, technologically proficient and both conceptually- and analytically-strong working environment. For Canada and the international community, the overall knowledge generated from this research will be directly applicable to establishing effective management and conservation practices for socio-economically important species such as salmonids, upon which food supply and job security depend. This will include a facilitation of decision-making regarding how to best prioritize population diversity within species – and the most-cost effective tools for doing so – for environmental assessments, climate change assessments, fisheries and wildlife management, and conservation.