Landscape, colonization and life history : their effects on genetic diversity in four sympatric species inhabiting a dendritic system

Abstract

To what degree are patterns of genetic structure in fragmented systems the result of contemporary landscape vs. history? We examined the distribution of genetic diversity as a function of colonization history and contemporary landscape in four fish species inhabiting a hierarchically fragmented, unaltered system, the Kogaluk drainage (Labrador): lake trout, longnose sucker, round whitefish, and lake chub. The footprint of colonization history was still observable in the three species where this issue was examined regardless of the generations since their arrival. ABC analyses suggest colonization took place from the southwest. The species exhibit similar diversity patterns despite different Nes and generation intervals. Contemporary gene flow was largely negligible except for gene flow from a centrally located lake. These results suggest landscape has driven colonization history, which still has influence on genetic structuring. The species are widespread. Understanding how they behave in the pristine Kogaluk provides a baseline against which to evaluate how other anthropogenically perturbed systems are performing. Improved understanding of historical and contemporary processes is required to fully explain diversity patterns in complex metapopulations