A comparison of two measures of competition

Data arising from replacement series experiments are used to estimate the effect of competition between the species. The Relative Crowding Coefficient (RCC) is typically used as a measure of competition. The standard method of estimating RCC uses the ratios 0:1, 1:1, and 1:0, but does not include the information from the 1:3 and 3:1 ratios. Novak et al. proposed an alternative measure of RCC that uses data from all five ratios. For each measure, an RCC of 1 indicates no competition. However, no test of the hypotheses H₀ : RCC = 1 versus H₁ : RCC ł 1 has been presented in the biological literature. Although approximations of the bias and variance for the standard RCC measure may be found in the statistical literature, these approximations have not been given for the alternative RCC measure. Further, limitations in statistical analyses for replacement series experiments have been identified as a problem. This article will develop formulas for the approximate bias and variance of the alternative RCC measure. Possible tests of the hypothesis of no competition will be introduced and assessed in a Monte Carlo study.