Characterizing the ecological effects of phenotypic diversity using the stoichiometric phenotype

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All animals have to eat. They consume nutrients to grow and reproduce, and also recycle nutrients in their waste. Animals therefore play an important role in the movement of energy and nutrients in their ecosystem, and their nutrition is key for understanding this role. My research program is motivated by characterizing how the diversity of animal life affects their role in the ecosystem. Diversity can be measured by counting different species. However, increasingly we recognize that diversity within the same species (intraspecific phenotypic variation) affects how animals interact with their ecosystem - how much nutrients and energy they require and consume, and how much waste they recycle. Intraspecific phenotypic diversity is ubiquitous in nature, and is affected by human activities. Over the next five years my students and I will investigate the ecological and physiological mechanisms by which intraspecific phenotypic variation affects animal nutrition. We are particularly interested in nutrient recycling, defined as the capacity of animals to regenerate nutrients in their waste, because it is an important process for the stability and productivity of ecosystems. We will specifically focus on how intraspecific variation in bone, which is rich in phosphorus, affects the ability of fish to acquire, assimilate, and recycle this important element. Together we call these measurements "the stoichiometric phenotype". We will study populations of the threespine sticklebacks (Gasterosteus aculeatus), an important evolutionary model species that varies tremendously in its bony characteristics. We will compare how stickleback with different bony structures ingest, digest, and recycle phosphorus in nature and in laboratory experiments. Intraspecific phenotypic variation and its consequences are especially important to study in human-impacted ecosystems, where phenotypes and genotypes can change rapidly and dramatically. The human population is growing, with more than half the population living in cities. The growth of cities has dramatic negative effects on the ecosystem, and causes big changes among and within animal species. The causes and consequences of intraspecific phenotypic trait variation in urban ecosystems are poorly understood. We will survey stickleback populations along an urbanization gradient on the west coast of Vancouver Island (British Columbia), in order to test how phenotypic diversity responds to urban pressure. We will assess how urbanization affects bony traits and diets, in order to assess if it also affects nutrition. This research program allows us to make rapid progress on critical, fundamental questions in ecology and evolution, and to better understand human impacts. By focusing on animal nutrition, we are able to make connections between animal diversity and its ecological consequences. The program provides training opportunities for graduate and undergraduate students.