Spatial dynamics of intraspecific genetic variation in European beech (Fagus sylvatica L.)

Fagus sylvatica is one of the most important tree species in Europe. Due to its extensive distribution
and dominance in its range, the performance of European forests in the contexts of perceived
climate change will largely depend on the reaction of beech forests. Adequate information
about the genetic diversity and structure of the species is indispensable for the conservation and
sustainable utilization of the forests. Forest management systems currently in use in Germany are
considered sustainable. However, their impact on the genetic diversity and spatial genetic structure
of F. sylvatica is largely unknown. In these contexts, the main objectives of this dissertation
were a) to assess the genetic diversity and differentiation of F. sylvatica at different spatial
scales, b) to determine the level and magnitude of fine-scale genetic structure of the beech
stands, c) to investigate the effect of forest management activities on the genetic diversity and
fine-scale genetic structure of the beech stands independent of the marker used and d) to compare
microsatellite and AFLP markers to estimate genetic diversity and structure of the stands,
and their applicability to detect management impacts on genetic structure of the stand.
Exhaustive sampling was performed in most of the plots to harvest the leaf samples from 3620
beech trees from 30 different stands located at three different regions (exploratories) covering
major differences in the population histories and natural geographical distribution of beech forests
in Germany. Ten beech stands, including managed and unmanaged, were sampled at each
exploratory. Within population and among population genetic variability and fine-scale genetic
structure was assessed by using two types of markers, codominant and biparentally inherited
microsatellite (six SSRs and three EST-SSRs) for all individuals and dominant AFLP markers
(126 loci) for a subset of 100 individuals from each plot across six beech stands. The differences
in genetic diversity, differentiation and SGS parameters between managed and unmanaged beech
stands were analyzed and their significance levels were estimated for all stands together and separately
at exploratory level.