highly significantp < .001
A interaction LM including species as a factor with a power term of 0.55 for instream distance captured well the saturating response, with instream distance, species, and their interaction being highly significant (Figure 5 ; F 3,2735 = 1094.0; p < .001; R 2 adj = 0.55). 3.2 Simulation – data comparison The stochastic simulations assuming a stepwise mutation model resulted in highly differentiated spatial patterns of population genetic diversity depending on the set of parameter values used (Figure 3 , Figure S5 and Figure S6 ).