Evolution in Changing Environments1
Anthropogenically-induced climate change and over-exploitation of natural resources are considerable challenges to species community composition and the ecosystem services they provide. Climate change presents multiple stressors including increased ocean temperature, acidification, reduced salinity, sea level rises which add to ecosystem complexity through synergisms and antagonisms among global and local drivers, often with additive effects that can disrupt community structure leading to reduced fitness, population decline, and local extinction, and potentially breaching thresholds that can overwhelm and collapse entire ecosystems. The ecological responses to climate change can lead to novel or altered species community structures with changes to food-web dynamics, altered population fitnesses, disrupted ecosystem processes, decreased productivity, and a greater incidence of disease. Such ecosystem changes are complex and poorly understood from a biological perspective, thereby making predictions is difficult and posing a challenge to marine resource managers and policy makers.
A changing climate and environmental stressors can affect marine ecosystems in many ways. For instance, marine animals, such as fish, are subject to changes in olfactory-driven behaviour due to ocean acidification while temperature changes and acidification in polar waters can induce physiologically plastic responses in fish. Likewise, environmental changes can result in both phenotypic and adaptive responses in marine plants. Yet the responses of marine organisms to changes in environmental stressors are varied: environmental induced alterations in the species’ life-cycles can result in changes in niche breadth leading to changes in distribution. While one species may thrive in a modified environment, others may be pushed close to local, or total, extinction, through antagonism and synergism brought on by changes to community composition.
Our researchers aim to document the current impact of climate change and other environmental stressors on marine ecosystems and the species, and to model and predict the impact of changes in the future. How does ocean acidification and temperature change affect species life cycles and how resilient are they to such perturbations? How important is population-level standing genetic diversity in enhancing species tolerance of environmental stress? How will environmental changes affect species’ distributions and community composition? In particular marine communities, which species are most vulnerable to changes, and how might such changes be arrested? Do tipping-points exist beyond which population crashes and extinction are inevitable? How do we integrate spatial analysis, niche modelling, and genetic analysis to predict the effects of changing environments on marine ecosystems? Thankfully, the answers to at least some of these questions are currently becoming clearer...