DISPERSAL OF INVERTEBRATES AMONG TEMPORARY PONDS: ARE GENETIC ESTIMATES ACCURATE?

Abstract

Dispersal is difficult to quantify in most temporary pond invertebrates. As a consequence, researchers often infer the movement of individuals from indirect estimates of gene flow. Here, we review the assumptions associated with the most common gene flow estimate, which approximates migration using a simple island model and assumes equilibrium. Particular attention is focused on empirical studies of temporary pond invertebrates, where nonequilibrium conditions may be particularly important. When populations have not reached a long-term equilibrium between the migration of genes and random drift, estimates of movement can be biased dramatically. Eight comparative and theoretical tests for ascertaining these biases are described here. In some cases, specific hypotheses regarding contemporary and historical processes can also be tested statistically using computer simulations. Although the accuracy of gene flow estimates in temporary pond species varies widely, empirical and theoretical methods for assessing this accuracy are almost always available.