Interplay between summer and winter climate change in reshaping marine biodiversity

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Strong swings in environmental extremes across seasons may pose a double jeopardy to species in years when detrimental conditions occur in both summer (such as heat waves and low oxygen events) and winter (cold spells). For instance, in species that overwinter by reducing their metabolic rate instead of feeding, bountiful summers are critical to surviving harsh winters. Likewise, remaining active during the winter requires adequate food resources to meet the energy required to withstand the winter season. Harsh winters followed by summers that are physiologically demanding or impose constraints on feeding may result in the death of individuals and population decline. Yet although the role of winter climate change in regions where cold months persist for more than half the year is an obvious force with potential to reshape biodiversity, the field of climate change ecology has focused on the biological impacts of increasing temperature, often in the warmest months of the year. My research program will tackle this gap in our understanding of how climate change influences individual physiology to shape biodiversity change by incorporating signals of winter climate change into field work, experiments and models. I predict energetic constraints and mortality will manifest most strongly during consecutive harsh winters and summers, which in turn will lead to the strongest changes in populations and communities in both space and time. To test for an interplay between seasonal conditions and biodiversity patterns, my program will manipulate the magnitude and duration of exposure to environmental parameters, quantify physiological limits, and provide the data to build energy budget, population and trophic web models. Model predictions will be tested against field survey data and experimental outcomes. This suite of approaches will translate to a capacity to (1) quantify temporal biodiversity patterns in different seasons; (2) project biodiversity change under different seasonal patterns of extreme events in space and time from first principles; and (3) develop theory and tools to bridge physiological, population, community and ecosystem scales. Our focus will be on taxa that are most vulnerable to climate change and play key community roles including top predators (seabirds), habitat-formers (seaweeds and sponges), those with cultural and economic value (Atlantic cod and lobster) or negative impacts (invasive green crab). By identifying seasonal trends as key climate-change drivers of biological responses, we will provide insights with significance for fisheries, predictions for the vulnerability of important ecosystems, and species invasions. My lab's research will lead the field of climate-change ecology by linking physiological models to biodiversity patterns in nature to reveal how changing seasonal dynamics, particularly winter conditions, are altering marine biodiversity patterns in Canada and beyond.