ABSTRACT
This chapter reviews compe- tition-stress-ruderal and resource competition theory and the associated literature on competition intensity and competitive traits. In plants, interference competition can occur by one individual overgrowing another. Work in arctic- alpine plant communities has supported the exploitation ecosystem hypothesis, finding that plant competition is more intense and herbivory less intense at higher habitat fertilities and productivities. Plant height, canopy diameter and area, and leaf shape were of secondary importance. Resource heterogeneity is a feature of all natural environments, and its potential importance for plant competition and coexistence has been a recent focus of competition research. Plants compete when demands on resources exceed resource supply. Stress is defined as any environmental condition that limits plant production, and disturbance as any environmental condition that removes plant biomass. Most research on heterogeneity and plant competition has focused on effects of spatial heterogeneity.
