Project Summary:

As in human societies, the natural environment is connected through a wide range of transport, propagation and communication processes. Fluxes of energy and matter between ecosystems modify food web interactions and nutrient cycling, and affect the diversity of plants, animals, and other organisms. Spatial linkages of ecosystems may be interrupted, however, by disruption in transport processes through time. Thus, ecological processes at any point in space can be affected by past and present flows of energy and nutrients. In order to understand complex ecological processes such as these we must explore the spatial and temporal variation, or ecological topology, of such phenomena. River otters (Lontra canadensis) transport nutrients from sea to land by feeding in the marine environment and using latrine sites along the coast. Thus, the behavioral dynamics of coastal river otter populations provides an excellent model system to explore the effects of spatial and temporal variation in inputs of marine carbon (C), nitrogen (N), and phosphorus (P) to terrestrial plants and soil organisms. Sociality in otters is solely driven by the benefits of cooperative foraging on schooling pelagic fishes. Therefore, any changes in the abundance and distribution of these prey through global warming, pollution, or harvest, could change the transport of nutrients to otter latrines. Using stable isotope analyses and genetic markers we will quantify the variation of nutrient transport by river otters and explore its effects on the diversity of the soil microbial community, nutrient cycling, plant uptake of marine nutrients, diversity of plants, plant growth, flowering and fruiting success. After establishing these responses to the variation in otter fertilization, we will develop a spatial model that will evaluate potential changes to the terrestrial landscape based on the distributions of schooling fish, otter activity, and C, N, and P transport by river otters, in response to climate change.