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From regionally predictable to locally complex population structure in a freshwater top predator: river systems are not always the unit of connectivity in N orthern P ike E sox lucius
Author(s) -
Bekkevold Dorte,
Jacobsen Lene,
HemmerHansen Jakob,
Berg Søren,
Skov Christian
Publication year - 2015
Publication title -
ecology of freshwater fish
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 55
eISSN - 1600-0633
pISSN - 0906-6691
DOI - 10.1111/eff.12149
Subject(s) - pike , esox , ecology , population , colonisation , range (aeronautics) , genetic structure , genetic drift , apex predator , habitat , biology , geography , genetic diversity , fishery , demography , sociology , fish <actinopterygii> , materials science , colonization , composite material
Contemporary genetic diversity is the product of both historical and contemporary forces, such as climatic and geological processes affecting range distribution and continuously moulded by evolutionary forces selection, gene flow and genetic drift. Predatory freshwater fishes, such as N orthern P ike E sox lucius , commonly exhibit small population sizes, and several local populations are considered endangered. Pike inhabit diverse habitat types, including lakes, rivers and brackish marine waters, thus spanning from small isolated patches to large open marine systems. However, pike population structure from local to regional scales is relatively poorly described, in spite of its significance to developing conservation measures. We analysed microsatellite variation in a total of 1185 N orth E uropean pike from 46 samples collected across both local and regional scales, as well as over time, to address two overarching questions: Is pike population structure associated with local and/or regional connectivity patterns, and which factors likely have the main influence on the contemporary distribution of genetic diversity? To answer this, we combined estimators of population diversity and structure to assess evidence of whether populations within (i) habitats, (ii) drainage systems and (iii) geographical regions are closer related than among these ranges, and whether patterns are temporally stable. Contrasting previous predictions that genetic drift obscures signals of postglacial colonisation history, we identified clear regional differences in population genetic signatures, suggesting a major effect of drainage divides on colonisation history and connectivity. However, several populations deviated from the general pattern, showing that local processes may be complex and need to be examined case‐by‐case.