The Committee on Evolutionary Biology (CEB) is a unique interdepartmental and inter-institutional graduate student training program dedicated to the study of Evolutionary Biology. Faculty and students in the program are engaged in interdisciplinary studies at time scales that range from single generations to the entire history of life and at organizational scales from the molecular to the global.
I am interested in why organisms live where they live and how biotic interactions (and abiotic interactions) can create interesting spatial patterns of organisms in nature. In particular, I study seagrasses and sand dollars. On sandy beaches in Washington state, these species are both dominant space occupiers. Seagrasses form dense beds that anchor and accumulate sediment and tasty organic matter, increase the oxygen in the water and sediment, and shelter high biodiversity, including juvenile herring and halibut, snails and sea slugs, crabs, worms, and much more. Sand dollars, which are relatives of sea urchins, aggregate and also form dense beds, bumping into each other and churning through sand in the process. Their hustle and bustle prevents many other species from living in these areas, and their aggregative behavior makes for patchiness within sand dollar territory too. When you get both species present on the same beach, like where I study them in the San Juan Archipelago, you get a dynamic, patchy mosaic, like a checkerboard of grass patches and sand dollar patches with slowly shifting boundaries, as they invade and disrupt each other, competing for space.
My research connects the inch-scale processes of what happens when a sand dollar contacts a seagrass shoot to the football-field-scale changing landscape of the beach. First, using field experiments I'm measuring how conditions change within the different kinds of beds as a result of these engineering activities and how these alterations affect rates of growth and territory change for each species. Second, using the data I’ve collected in my field experiments, I’m using the rates of growth and change to build probabilistic models that predict the future distributions of species on the beach, testing different hypotheses about what factors are important to patterns. I’m using a time-series of aerial images of my field site to test these predictions against what’s actually happening on longer scales of time and space. Finally, I’m integrating lab experiments examining sand dollar aggregative behavior with individual-based models to test whether this neat behavior affects landscape-level processes.Read More about Amy Henry or visit the Spotlight Archive.