4.1 Detection of sympatric populations and divergence among them
Conspecific populations that coexist in the same habitat without obvious ecological divergence (cryptic sympatry) is a type of “hidden” biodiversity that we still have limited knowledge of (Struck et al., 2017). The present results suggest that the occurrence of cryptic sympatry is a common phenomenon in these mountain lake systems. We detected such structures in over 40 percent of the lakes, and they were stable over time in occurrence as well as in amount of divergence. Our observed F ST among sympatric populations are of a similar order of magnitude as previously reported for cryptic, sympatric, salmonid populations (Andersson et al., 2017a; Aykanat et al., 2015; Marin et al., 2016; Wilson et al., 2004).