Abstracts (first author)


Sex-specific fitness consequences of translocation in house sparrows

Author(s): Pärn H, Skjelseth S, Herfindal I, Sæther B, Stokke BG, Ringsby T, Jensen H


Translocations are increasingly used in conservation programmes to reinforce small populations. Success of translocations in relation to characteristics of the species, the location or the translocation event, such as propagule size, is well studied. However, much less is known about individual variation in genetic contribution to the release population. Here, we compare sex-specific fitness of resident and introduced individuals based on genetic parentage, following a translocation experiment in house sparrows. The genetic mating pattern revealed assortative mating based on origin, where introduced males were highly unlikely to mate with resident females. Introduced males had fewer mates and fledglings than resident males. Origin had no effect on number of fledglings in females. The effect of origin on number of fledglings was sex-specific as indicated by the significant interaction between sex and origin. The number of recruits and total annual fitness contribution did not differ between resident and introduced individuals. In the house sparrow, male badge size has a function in intra- and intersexual selection. It is likely that the influence of badge size is of greater importance for introduced males, which have to compete with resident males over nest sites and mates. However, the relationship between number of mates and badge size did not differ between resident and introduced males. Still, the effect of badge size on number of fledglings was stronger in introduced males. Our results provide insights about sex-specific individual heterogeneity in reproductive success of introduced individuals, and the potential role of sexually selected traits for the genetic consequences of a translocation event.

Abstracts (coauthor)


Dispersal propensity may vary considerably between individuals in a population. Still, dispersal remains one of the least understood processes in ecology and evolution. In this study, we investigate individual variation in juvenile movement during the onset of the dispersal phase in four insular house sparrows Passer domesticus populations in northern Norway. The predictors were clutch size, hatch day, sex and morphology. The study islands differ in degree of patch isolation, configuration of suitable habitat, and characteristics of the matrix habitat. Thus, it was possible to assess the importance of such landscape features on movement. On one of the islands, movement rate was negatively related to hatch day. This pattern may be generated by age-dependent movement since early born individuals are older when the dispersal phase is initiated. However, we suggest that this relationship rather is a result of seasonal variation in the environment experienced by the nestlings, which affects their phenotype and propensity to disperse. Clutch size, sex, body size, mass and condition did not significantly explain variation in movement. On the other hand, movement rate seemed to decrease with increasing patch isolation, i.e. distance between patches and hostility of the matrix habitat. This suggests that habitat configuration is an important factor influencing movement and dispersal capacities of juvenile house sparrows.

Spatio-temporal dynamics of genetic variation and effective population size in fragmented house sparrow populations

Author(s): Jensen, H, Baalsrud HT, Hagen IJ, Myhre AM, Holand AM, Billing AM, Tufto J, Pärn H, Ringsby TH, Slate J, Sæther B


Habitat fragmentation is a major threat to biodiversity: by reducing population sizes and gene flow between populations it affects genetic structure and effective population size (Ne), which have important implications for population dynamics and evolutionary processes. We used natural house sparrow (Passer domesticus) populations in Norway as a model system to investigate if population type (i.e. mainland or island), geographic distance, adult population size (N), immigration rate and sex ratio explained intra- and interpopulation genetic variation and Ne of fragmented populations. Data from microsatellite genotyping across multiple populations and generations was used. Our results showed that intrapopulation genetic variation was lower and the occurrence of population bottlenecks more frequent on islands than the mainland, and the general level of genetic differentiation was higher between islands than between mainland populations, but only at shorter distances. Furthermore, genetic differentiation decreased, whereas intrapopulation genetic variation and Ne/N-ratios increased with immigration rates. Both intrapopulation genetic variation and Ne increased with population size. However, genetic Ne was much larger than demographic Ne (often even >N), probably due to a greater effect of immigration on genetic than on demographic processes. In constrast, genetic Ne for the metapopulation were within the expected range (<N), suggesting that in fragmented populations even low levels of gene flow may make the total metapopulation the appropriate scale of estimation. We also developed a genome-wide 10 000 Single Nucleotide Polymorphism (SNP) chip for the house sparrow and screened individuals from four populations. This demonstrated that genome-wide marker data gave results similar to microsatellites. Our results are relevant for a better understanding of evolutionary processes and hence conservation of threatened populations.


Chairman: Octávio S. Paulo
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XIV Congress of the European Society for Evolutionary Biology

Organization Team
Department of Animal Biology (DBA)
Faculty of Sciences of the University of Lisbon
P-1749-016 Lisbon


Computational Biology & Population Genomics Group