Data from: Isolation-by-distance in landscapes: considerations for landscape genetics

In landscape genetics, isolation-by-distance (IBD) is regarded as a
baseline pattern that is obtained without additional effects of landscape
elements on gene flow. However, the configuration of suitable habitat
patches determines deme topology, which in turn should affect rates of
gene flow. IBD patterns can be characterized either by monotonically
increasing pairwise genetic differentiation (for example, FST) with
increasing interdeme geographic distance (case-I pattern) or by
monotonically increasing pairwise genetic differentiation up to a certain
geographical distance beyond which no correlation is detectable anymore
(case-IV pattern). We investigated if landscape configuration influenced
the rate at which a case-IV pattern changed to a case-I pattern. We also
determined at what interdeme distance the highest correlation was measured
between genetic differentiation and geographic distance and whether this
distance corresponded to the maximum migration distance. We set up a
population genetic simulation study and assessed the development of IBD
patterns for several habitat configurations and maximum migration
distances. We show that the rate and likelihood of the transition of
case-IV to case-I FST–distance relationships was strongly influenced by
habitat configuration and maximum migration distance. We also found that
the maximum correlation between genetic differentiation and geographic
distance was not related to the maximum migration distance and was
measured across all deme pairs in a case-I pattern and, for a case-IV
pattern, at the distance where the FST–distance curve flattens out. We
argue that in landscape genetics, separate analyses should be performed to
either assess IBD or the landscape effects on gene flow.