title: Isolation-by-distance in landscapes: considerations for landscape genetics.
abstract: 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.
authors: 1] Planning of Landscape and Urban Systems, ETH Zurich, Stefano-Franscini-Platz 5, Zurich, Switzerland [2] WSL Swiss Federal Research Institute, Zürcherstrasse 111, Birmensdorf, Switzerland.
authors: M J
authors: MJ
authors: van Strien
authors: 1] WSL Swiss Federal Research Institute, Zürcherstrasse 111, Birmensdorf, Switzerland [2] Department of Environmental System Sciences, ETH Zurich, Universitätsstrasse 16, Zurich, Switzerland.
authors: R
authors: R
authors: Holderegger
authors: 1] Earth and Ocean Sciences, Cardiff University, Main Building, Park Place, Cardiff, UK [2] Institute of Earth Sciences, Utrecht University, Budapestlaan 4, Utrecht, The Netherlands.
authors: H J
authors: HJ
authors: Van Heck
mesh_terms: D003198:Computer Simulation; D004777:Environment; D051456:Gene Flow; D005828:Genetics, Population; D005843:Geography; D008957:Models, Genetic; D013269:Stochastic Processes