Untersuchung zur Brutbiologie und Populationsgenetik der Wiesenweihe (Circus pygargus Linnaeus, 1758) mittels Mikrosatelliten-Analyse

Montagu’s harrier (Circus pygargus) breeds on the ground and is endangered due to intensifi-cation of agricultural activities. Therefore, in most European countries the species is in high demand of intensive conservation efforts. The aim of this work was to identify novel microsa-tellite loci for Montagu’s harrier that can be used for breeding biological and population genetic analyses by means of paternity tests. These data could be used for conservation manage-ment. The work concentrated on the largest population in Germany: Mainfranken, Bavaria. Between 2000 2012 from chicks and between 2009 2012 from adult females blood samples were collected from this population. By means of 454-pyrosequencing 14 STR loci could be identified for use in parentage analyses. Another two loci from related species were found and three multiplex-PCR sets were developed for the microsatellite analysis. Genotyping of Mon-tagu’s harrier samples was performed by capillary-array electrophoresis using fluorescently labelled primers. Altogether 204 families containing 1276 samples from chicks and 123 samp-les from adult females were analysed via paternity tests. Investigation on age of first breeding revealed an age of three years for males and of two years for females. Nests of first-breeding males were located 15 km away from the hat-ching site, whereas those of females were 22 km. 41.2% of males and 29.4% of females can be considered to be philopatric, since distances between nests of first breeding and hatching site were ≤10 km. Recruitment rates of males were 4.9% and for females 2.9%. Sex ratio of chicks was biased towards males (53.1%). Altogether, only 4% of the studied chicks returned to the breeding colony. Adult males seem to be the more philopatric sex because nesting dis-tances between two consecutive years were found to be 1.7 2.9 km (6.4 km for females). Concerning results on partner fidelity, the breeding system of the species can be considered to be seasonally monogamous. Rates of bigamy (1.5%, three of 204 families) and extrapair youngs (0.5 1% of broods and 0.3% of all chicks) seem to be very low. Only 25.5% of fema-les bred with the same partner in more than one year. A significant higher breeding success could be detected when females remained with the same partner compared to females that changed their partner every year. Moreover, nests of faithful females were located closer to the nest of the previous year, than those of non-faithful females. Mean age of males obser-ved during the study period time was 3.8 years and 3.6 years for females. Individual birds reached much higher ages of 7-10 years. Furthermore, yearly survival rates of 60 82% could be determined for females. With regard to conservation efforts and management strategies, eight European populations were investigated for genetic exchange. Result indicate pro-nounced mixing of these populations, since they were found to be genetically homogenous. More detailed analyses on population genetics is needed to derive consequences for conser-vation. All findings are discussed regarding to biological and methodological aspects