Abstract
Nitrogen is the primary limiting nutrient throughout the boreal forest. Previous work has demonstrated that ericaceous shrubs act as drivers in this system by reducing nutrient availability, driving changes in community composition, reducing productivity, and increasing carbon storage in stable soil pools. Therefore, understanding specific mechanisms by which ericaceous shrubs regulate N cycling is of great interest in both the field of ecology, and in the forest industry. We plan to use a variety of isotope labeling experiments and 15N natural abundance measurements to determine: 1) whether litter inputs from the most nitrogen-use-efficient ericaceous shrub (Empetrum hermaphroditum) allows it to overtake the N cycle by partitioning N into complex organic pools that other species cannot access, 2) whether this partitioning mechanism provides a competitive advantage for this species, and 3) whether this litter - N uptake feedback is a successional driver in this system. By investigating the mechanisms by which N is partitioned among these species, we believe we will be in a strong position to provide a greatly improved knowledge for N cycling in boreal forests.
Sweden