Using empirical field data of aquatic insects to infer a cut-off slope value in asymptotic models to assess inventories completeness

Abstract

The selection of the most appropriate model is essential to predict the potential species richness of a siteor landscape. Species accumulation curves have been used as a basic tool for comparing richness when differentsampling protocols have been applied. Among the parameters generated by these models the slope has been cited asan indicator of completeness without regard to a defined cut-off value. In this work, we fit 12 field data sets of aquaticColeoptera (Hidalgo) and Odonata larvae (Michoacán) to 2 asymptotic models (Clench and Linear Dependence) inorder to calculate the slopes at the maximum effort and relate them with efficiency. Then, the theoretical effort neededto achieve the 95% of the lists was calculated for each data set in order to get the theoretical slopes. The averageslope value found was 0.01 with a variance of <0.001, so we propose this value as indicative of a list reaching 95% ofcompleteness for data obtained from similar sampling protocols.