Physiological links between individual quality and life-history strategies in Arctic birds

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The quality of the individual and its surrounding environment should shape life-history strategies. Perhaps the best place on earth to examine the evolution of the trade-offs that drive these optimal strategies are Polar environments since i) they experience large variation in environmental quality, ii) many species rely on both local and stored resources to fuel reproduction, and iii) the short reproductive season has strong effects on fitness. As such, individuals must balance many internal and external trade-offs to optimize reproductive decisions. To understand how individual quality influences fitness in the Arctic, I examine underlying stress-mediated physiological mechanisms since they are predicted to directly connect the organism to its environment. I focus on how the relationship between individual physiological quality, reproductive decisions and fitness shape key life-history traits predicted to influence fitness such as the timing of arrival on breeding grounds, the timing of breeding and the quantity and quality of offspring. I concentrate primarily on individual variation in the quality-mediated physiological traits predicted to drive optimal strategies since it is the raw material that natural selection acts on. The main goals of my research are to 1) examine the role of allostatic load (i.e., individual quality) and environmental stress (i.e., climatic variability) in mediating reproductive strategies and 2) investigate direct (i.e., quality) and indirect (i.e., carry-over effects) quality-mediated mechanisms that drive reproductive decisions. Since Arctic-breeding species face multiple decisions during wintering, migration and pre-breeding, I integrate across multiple life-history stages as so little is known about how the optimization of strategies across stages influences fitness. The strength of my research comes from integrating concepts and techniques from Evolution, Ecology and Physiology. My research not only informs evolutionary biologists about the mechanisms driving life-history decisions, it also provides applied ecologists with the underlying mechanisms to understand why climate-induced changes in the timing of reproduction affect population persistence through changes in individual reproductive success.