Fattorini               Australian bird abudances.
Ganeshaiah              Indian dung beetles from Ganeshaiah et al.
                        (1997)
Mehrabi                 Costa Rica dung beetle counts from Mehrabi et
                        al. (2014)
k_hetang                Preemption parameter estimation by He and Tang
k_ls                    Preemption parameter estimation by least
                        squares regression
k_may                   Preemption parameter estimation by the equation
                        of May
k_ml                    Preemption parameter estimation by maximum
                        likelihood.
preemption.fit          Estimation of the preemption parameter of a
                        geometric series by various methods
preemption.t            Preemption t test
raplot                  Rank-abundance plot
raplot.paired           Rank-abundance plot for two samples
