Research Interests:
The ecology of aquatic plants is the focus of my laboratory. For some years, research has centered on marine vascular plants called seagrasses. Seagrasses provide many animals with their food, either directly (e.g., waterfowl that graze the leaves, underground parts, and seeds) or indirectly via food chains based on decaying seagrass parts (e.g., many commercially valuable invertebrates and fish). My interests include the process of leaf decay and the food chains associated with seagrass detritus, as well as the establishment and expansion of seagrass populations, and community interactions.

Some of my research efforts have gone into a long-term study of the interactions between seagrass populations and the physical environment. Since seagrasses typically occupy nearshore, shallow-water habitats, they are often disturbed by activities such as the construction of marinas and ports. While such activities can cause both immediate and long-term losses of seagrass habitat, changes to water-flow patterns and water clarity in at least one location have led to a large expansion of the seagrass population. Studies of the expanding seagrass bed and its physical environment have begun to reveal some of the delicate interactions that govern the system.

Recently I have returned to studies of the processing of plant detritus. Now, however, the focus is on decay of terrestrial leaf litter in the freshwater environment. With changes in land-use patterns, e.g., from forest to field, come changes in vegetation types that in turn may alter the aquatic community. Management of these resources for the long-term benefit of all requires a detailed understanding of ecological relationships.

While duties as Associate Dean fully occupy my work days and preclude an active research program at this time, I am always glad to discuss research interests that fall within the areas outlined above.

Harrison, PG. 1987. Natural expansion and experimental manipulation of seagrass (Zostera spp.) abundance and the response of infaunal invertebrates. Estuar. Coast. Shelf Sci. 24: 799-812.

Harrison, PG. 1990. Variations in success of eelgrass transplants over a five-years' period. Envir. Cons. 17: 157-63.

Harrison, PG. 1991. Mechanisms of seed dormancy in an annual population of Zostera marina (eelgrass) from the Netherlands. Can. J. Bot. 69: 1972-1976.

Harrison, PG. 1993. Variations in demography of Zostera marina and Z. noltii on an intertidal gradient. Aquat. Bot. 45: 63-77.

Tarbotton, M. and Harrison, PG. 1996. A Review of Recent Physical and Biological Development of the Southern Roberts Bank Seagrass System 1950-1994. Prepared for the Roberts Bank Environmental Review Committee, Vancouver.