Schlussbericht zum Projekt: Übertragbares Managementkonzept für Arnica montana - Teilvorhaben 2: Etablierung, Standardisierung und Qualitätskontrolle des genetischen Monitoring-Systems für Arnica montana

For the endangered and declining plant species Arnica montana a standardized genetic monitoring system was developed. This is based on 14 nuclear microsatellite markers which were optimized for analysis and characterized for their molecular variation. Using reference samples and allelic ladders, i.e. mixtures of the most frequent alleles, a standardization is now possible which allows to match data from different laboratories to enable long-term monitoring programs. The genetic markers were applied in cooperation with the project partners to study the quality of lowland populations of A. montana in Hesse. We found that the decline of the populations also has a genetic component since many populations are relicts consisting only of one or very few clonal groups, which hardly reproduce sexually. This is statistically correlated with population size although this is not the only indicator for population quality. While A. montana is mostly protected from the negative effects of inbreeding by a self-incompatibility system, this trend leads to a massive loss of genetic variability which indicates that the populations will not survive long-term without suitable management efforts. In the project region there are still some populations in better shape with sufficient genetic variability which could be used as sources for efforts of genetic rescue. Here, the genetic population structure should be considered which clearly divides the Hessian populations into a north-western group and a south-eastern group. Even within these groups, the populations exhibit little gene flow, which indicates that it is unlikely that natural gene flow might be a source for regeneration of genetic diversity. For measures of genetic rescue, we currently recommend to use populations from within the same genetic group. We conducted controlled crosses to assess the effects of inbreeding and outbreeding on the plant fitness. We could show that the self-incompatibility leads to reduced seed set but within the time frame of the project we could not study the second-generation offspring which might exhibit signs of possible outbreeding depression due to technical problems. This is, however, planned for the coming year. The genetic assessment of A. montana in Hesse produced valuable insights and recommendations for the practical management beyond the project region. This was disseminated on two conferences for conservation practitioners and scientists and in an informative practical guide which is freely available.