Grant: Discovery Grants Program - Individual

Foodwebs in most ecosystems are sustained by plants. Consumption of living plant material is often minimal, and the bulk of the plant production enters the detrital, or non-living, carbon pool. Fungi and bacteria initiate incorporation of this detritus into food webs. Microbial decomposition is therefore a key process both for plants (through release of nutrients) and animals (by making plant litter more nutritious to consumers). In many streams, a specialized group of higher fungi, aquatic hyphomycetes, dominates decomposition of the most important source of plant remains, i.e., autumn-shed leaves. Invisible to the naked eye, they nevertheless make a major contribution to the nutrition of stream invertebrates and therefore indirectly to fish. In my proposed research, I intend to apply molecular techniques to more accurately determine which fungal species occur in various streams, and how their occurrence is influenced by the riparian vegetation, by water chemistry, and by geography. There is a growing concern that accelerating species extinction rates due to anthropogenic stresses jeopardizes functions and services of ecosystems. Aquatic fungal diversity is threatened by increased deposition of nitrogen, rising temperature, and pollutants such as heavy metals. Our proposed research will investigate the effects of such changes on fungal diversity and functions in streams, and potential consequences for the upper levels of the aquatic food webs.