0129493 Competition can play a key role in structuring plant communities, and understanding the mechanisms of plant competitive interactions is therefore critical for successful management of natural and cultivated systems. Yet despite years of study, the nature of plant competitive interaction and their relationship to environmental conditions is incompletely understood and continues to be debated. Belowground competition and its relation to fine-scale heterogeneity in soil resources is a particularly little explored area, despite the ubiquity of soil heterogeneity in nature. This research will use experimental and modeling approaches to investigate root foraging traits and their relationship to plant competitive ability and plant community diversity in spatially heterogeneous soil. Greenhouse and field experiments will be used to measure the scale, precision, and rate of root foraging and their relationship to the competitive ability of herbaceous perennial species, including an important invasive weed. An especially novel focus of this research is the phenomenon of belowground size asymmetry and its role in plant competitive ability and community structure. Field experiments and simulation modeling will examine whether fine-scale heterogeneity affects competitive size symmetry and competitive hierarchies, and the consequences for plant species coexistence and the maintenance of plant community diversity. This research has the potential to redirect our understanding of root competition and its role in the structure of plant communities.
