Estimating the richness of species with variable mobility

The vast majority of species are animals that, unlike most plants and fungi, are variably and often highly mobile. While species' mobility affects species' probabilities of being sampled, effects of movement on the estimation of species richness have yet to be systematically investigated. Information-rich abundance-based estimators may be able to address variably mobile species but the accuracy of these estimators has also yet to be investigated. Here, we address both issues by variably sampling simulated landscapes with up to 250 species and evaluating the performance of ten non-parametric estimators and one species accumulation curve. Our results show that some abundance-based estimators are as accurate as better known and tested incidence-based estimators. Increased movement heterogeneity between the species reduced estimator performance by reducing the sample coverage, which systematically determined which estimator was most accurate. Based on these findings, we present the first decision framework for choosing the most accurate of many available abundance-based species-richness estimators. These decisions, based on data coverage, can significantly improve investigators' ability to estimate faunal species richness.