Population Genetics

In my Diploma thesis I am comparing the genetic structure of two blackcap (Sylvia atricapilla) populations. One population located in the municipal forest “Mooswald” near Freiburg, the other one located in upper Austria close to Kefermarkt. In central European blackcaps a new migratory route to the North-West has recently been established. The result is a new migratory divide with the traditional South-West migrants wintering in Spain and Africa, and about 10% of the Mooswald-population moving on the North-West route to the British Isles.

The population in upper Austria is even more interesting, since it comprises three different migratory routes owing to its geographic location north of the Alps: to the South-West (Spain), to the South-East (eastern Africa) and, of late, also to the North-West (UK).

Genotypes based on Microsatellites can be very helpful to explore genetic differentiation between populations, and maybe even subgroups within these populations, depending on the amount of geneflow still underway. Combined with stable isotope ratio analysis (SIRA), which tell us whether a bird has been wintering in Britain or Spain, the results can help to complete the picture of the dynamics of a potential sympatric speciation in the Freiburg population.

Within the Austrian population SIRA is not able to discriminate between SW and SE- migrants. To help getting a better picture of the composition of this population I will use genotypes of known SW and SE- migrants based on ring recoveries to assign the birds of upper Austria to one of these groups at the basis of their genotypic similarity.

This study could also contribute to understanding whether the new NW migration route has its origin in only one population, or if the change of migratory pattern has been developed more than once independently.