Population genetic patterns in continuous environments in relation to conservation management

Abstract: Genetic variation is a prerequisite for the viability and evolution of species. Information on population genetic patterns on spatial and temporal scales is therefore important for effective management and for protection of biodiversity. However, incorporation of genetics into management has been difficult, even though the need has been stressed for decades. In this thesis population genetic patterns in continuous environments are described, compared among species, and related to conservation management. The model systems are moose (Alces alces) in Sweden and multiple species in the Baltic Sea, with particular focus on the Northern pike (Esox lucius). The spatial scope of the studies is large, and much focus is dedicated towards comprehensive sampling over large geographic areas. The moose population in Sweden is shown to be divided into two major subpopulations, a northern and a southern one. Both subpopulations show genetic signals of major population bottlenecks, which coincide with known population reductions due to high hunting pressure (Paper I). The Northern pike in the Baltic Sea shows relatively weak, but temporally stable population genetic structure. An isolation by distance pattern suggests that gene flow primarily takes place among neighboring populations, either over shortest waterway distance or along the mainland coast, with island populations acting as stepping stones (Paper III). In a comparative study of seven Baltic Sea species no shared genetic patterns were found, either in terms of genetic divergence among or genetic diversity within geographic regions. These results complicate the incorporation of genetic data into management, because it suggests that no generalization can be made among species in the Baltic Sea, but that species-specific management is needed (Paper II). Over the last 50 years, 61 species in the Baltic Sea have been studied with respect to spatial genetic patterns. For over 20 of these species information of direct relevance for management is available. Relevant information is synthesized into management recommendations (Paper IV). This thesis provides vital information on spatial and temporal genetic structure for a number of ecologically and socio-economically important species. It shows that such information is important to consider species by species and that both local and metapopulation approaches are needed to effectively manage genetic diversity in e.g. moose and pike. Further, it identifies for which organisms in the Baltic Sea genetic information exists, how it can be used, and where important information is lacking. In order to successfully make use of genetic data in management, effective communication channels between academia and policy-makers are needed.