Dominance-diversity curves summarise the abundance and evenness of species within a community, visually representing simple diversity metrics and showing patterns of competition and niche differentiation (Wilson 1991, Whittaker 1965). Changes in dominant and rare species can have important consequences for ecosystem functioning and are not captured by metrics such as species richness (Hillebrand et al. 2018).
The x-axis of the curve displays the abundance rank, with the most abundant species ranked 1, the second most abundant 2 etc. The y-axis displays the relative abundance of the species. Species richness is summarised as the number of species ranked on the x-axis. Species evenness is summarised in the slope of the curve – the steeper the gradient the lower evenness.
Species diversity monitoring generates abundance and diversity data that can be used to calculate dominance-diversity curves (see Species diversity, Relative abundance for methodologies).
The goeveg package in R contains the racurve function, for fitting Whittaker plots for community data.
Targets on changes in relationship between species evenness and abundance of specific species will depend on the project aims (e.g. dominance relationships between target species for different habitats).