Inference of the number of clusters in simulated data. These four panel report examples of outputs from single simulations of the function find.clusters used to identify the number of clusters in data simulated according to for four different population genetics models (a: island model; b: hierarchical island model; c: hierarchical stepping stone and d: stepping stone; see Figure 2). Bayesian information criterion (BIC) is provided for different numbers of clusters. The chosen number of clusters is the minimum number of clusters after which the BIC increases or decreases by a negligible amount. The actual number of populations (K) is indicated by the dotted line.