| With more and more human-induced fragmentation of formerly contiguous habitat, many sensitive species, such as the southern dunlin (sydlig kärrsnäppa, Calidris alpina schinzii), have suffered large population declines. To preserve biodiversity, which has become a major focus of conservation policies, we need detailed knowledge of factors influencing the persistence of local populations in fragmented landscapes. One of many threats to such small and isolated populations is loss of genetic diversity, which results in reduced individual fitness and increased risk of population extinction. Several studies have used translocation experiments to demonstrate that the introduction of new genes, thereby artificially creating much needed gene flow, may ultimately be the only way to rescue some species from the brink of extinction.
Together with my collaborators, I have recently documented severe effects of reduced genetic variation (caused by e.g. inbreeding) in a rapidly declining population of southern dunlins on the Swedish west coast. This shorebird breeds on short-grazed coastal pastures and represents one of many threatened species typical for the agricultural landscape. Although the other two remaining populations of southern dunlins in Skåne and on Öland are still somewhat larger than in Halland, they are most likely suffering from similar threats of genetic deterioration. Building on this existing data set, I will investigate the current levels of genetic diversity within Swedish populations of this shorebird using two different molecular markers. Moreover, I will assess the extent of population differentiation caused by genetic drift and inbreeding that may have occurred during the last century.
In addition to a much needed comparison of two of the most commonly used molecular markers, the study will provide a better understanding of the various genetic problems of small populations. Furthermore, if the proposed study reveals that southern dunlin populations in Sweden have indeed genetically diverged from one another, the exchange of genes between populations (by swapping eggs) may be able to genetically rescue this endangered species. The results will thus provide valuable guidelines for conservation agencies on the optimal recovery strategy for this and similar species in the agricultural landscape. The here proposed research is therefore highly relevant for the foundation’s aim to support a rich natural environment in Sweden.
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