Published online by Cambridge University Press: 29 January 2010
Ecosystems have long been categorized by their function and structure (Odum 1953) and dominance and diversity are among the most common structural parameters measured in plant communities. The dominance of a plant species over another has been defined by having (1) more individual plants in a given sampling plot, (2) more collective biomass, or (3) greater cover (i.e. leaf area), but implicit in all definitions is a better ability to capture resources, grow and compete. Alternatively, diversity is a community-wide parameter encompassing both the raw number of species and the distribution of individual plants among them. Combining dominance and diversity together gives curves that show the distribution of abundances within a community (Whittaker 1965, Wilson 1991) and explore how these two aspects of structure relate to each other, change over time, and compare between communities separated in time or space. These curves are also effective in displaying contrasting patterns of species richness, highlighting differences in evenness among assemblages, and comparing species abundance patterns across communities (Magurran 2004). Indeed combining the dominance of particular species and the relative importance of that species within a community can suggest a ranking in competitive success and niche differentiation.