Abstract of paper 1:

Werth, S., H. H. Wagner, R. Holderegger, J. M. Kalwij, and C. Scheidegger. Submitted. Effect of stand-replacing disturbances on genetic diversity of an old-forest associated lichen. Molecular Ecology.

Lichens associated with old forest are commonly assumed to be negatively affected by tree logging or natural disturbances. However, in this study performed in a spruce-dominated sylvopastoral landscape in the Swiss Jura Mountains, we found that genetic diversity of the epiphytic old-forest lichen Lobaria pulmonaria depends on the type of disturbance. We collected 923 thalli from 41 sampling plots of 1 ha corresponding to the categories stand-replacing disturbance, intensive logging and uneven-aged forestry, and analysed the thalli at six mycobiont-specific microsatellite loci. We found evidence for multiple independent colonisations of demes located in areas affected by stand-level forest disturbance. Using spatial autocorrelation methods, the spatial scale of the genetic structure caused by the clonal and recombinant component of genetic variation was determined. Spatial autocorrelation of gene diversity was strong at short distances up to 150 m in all three disturbance categories, with the strongest autocorrelation for demes affected by stand-replacing disturbance. The spatial autocorrelation was predominantly attributed to clonal dispersal of vegetative propagules. After accounting for the clonal component, we did not find significant spatial autocorrelation in gene diversity. This pattern may indicate low dispersal ranges of clonal propagules, but random dispersal of sexual ascospores, indicating that there was no dispersal limitation of ascospores. Genetic diversity was highest in demes affected by intensive logging at forest-stand level, and lowest in demes affected by stand-replacing disturbance. Our results suggest that genetic diversity of epiphytic lichen demes may not necessarily be impacted by stand-level disturbances for extended time periods of many centuries.