Simulation modeling reveals the evolutionary role of landscape shape and species dispersal on genetic variation within a metapopulation

Abstract

Different shapes of landscape boundaries can affect the habitat networks within them and consequently the spatial genetic‐patterns of a metapopulation. In this study, we used a mechanistic framework to evaluate the effects of landscape shape, through watershed elongation, on genetic divergence among populations at the metapopulation scale. Empirical genetic data from four, sympatric stream‐macroinvertebrates having aerial adults were collected from streams in Japan to determine the roles of species‐specific dispersal strategies on metapopulation genetics. Simulation results indicated that watershed elongation allows the formation of river networks with fewer branches and larger topographic constraints. This results in decreased interpopulation connectivity but a lower level of spatial isolation of distal populations (e.g. those found in headwaters) occurring in the landscapes examined. Distal populations had higher genetic divergence when their downstream‐biased dispersal (relative to upstream‐ and/or overland‐biased dispersal) was high. This underscores the importance of distal populations influencing genetic divergence at the metapopulation scale for species having downstream‐biased dispersal. In turn, lower genetic divergence was observed under watershed elongation when the genetic isolation of distal populations was decreased in such species. This strong association between landscape shape and evolutionary processes highlights the importance of natural, spatial architecture in assessing the effectiveness of conservation and management strategies.

Dispersal behaviour and riverine network connectivity shape the genetic diversity of freshwater amphipod metapopulations

“…In parallel, theoretical models that address the effect of spatial connectivity of riverine networks on genetic variation (Morrissey & de Kerckhove, 2009 ; Paz‐Vinas & Blanchet, 2015 ; Paz‐Vinas et al, 2015 ), on evolution of dispersal (Henriques‐Silva et al, 2015 ), and emergence of neutral genetic structure (Fronhofer & Altermatt, 2017 ; Stokes & Perron, 2020 ; Thomaz et al, 2016 ) have demonstrated that dispersal along riverine networks has a direct imprint on the genetic structure and diversity of the inhabiting organisms. While these theoretical models provide direct testable predictions, a direct comparison between within‐population genetic diversities estimated from empirical data and predictions from theoretical models assuming an identical riverine network has been largely lacking (but see Chiu, Li, et al, 2020 ; Chiu, Nukazawa, et al, 2020 ).…”

A Bocage Landscape Restricts the Gene Flow of Pest Vole Populations

“…Landscape characteristics are a key factor in the population dynamics of most animal species [ 1 , 2 , 3 ]. Their relative influence on population connectivity not only depends on patch configuration, but also on behavioural patterns related to the response of individuals to a given landscape [ 4 , 5 ].…”

Quantifying isolation-by-resistance and connectivity in dendritic ecological networks

“…This in turn promotes asymmetric gene flow and a source-sink metapopulation structure (Campbell Grant et al 2007). Consequently, a prevailing trend is for a downstream increase in allelic diversity (Paz-Vinas and Blanchet 2015, Paz-Vinas et al 2015, Blanchet et al 2020), whereas unique genetic variation is most often retained within more peripheral headwater populations (Morrissey and De Kerckhove 2009, Chiu et al 2020b).…”