摘要: Many measures of community structure, such as diversity indices and rank-abundance curves, represent “snapshots in time”-which do not capture the temporal dynamics of ecological systems. For example, species richness (ie, the number of species present) is a common metric to characterize ecological communities. However, species richness may be a poor indicator of community change if there is turnover in the identity but not the number of species present over time (Collins et al. 2008; Cleland et al. 2013). Similarly, species rank abundances can reorder through time, even when the pool of species present remains relatively stable. Within-year rank abundance curves fail to capture this dynamic, and other tools are needed to quantify within-community reordering without masking informative temporal shifts in internal dynamics (Collins et al. 2008). codyn includes three functions to characterize temporal shifts in …