Seasonal growth pattern in the lichen Pseudocyphellaria berberina in north-western Patagonia

Seasonal growth increments (%) were measured in the foliose epiphytic lichen Pseudocyphellaria berberina in north-western Patagonia. Growth was determined by measuring increase in weight (expressed as percentage of the original biomass) in transplanted thalli. Transplants were either hung freely from wooden frames or attached to tree trunks in a Nothofagus dombeyi forest and then weighed every three months between January 2001 and April 2003. The influence on growth increment of treatment, donor thallus, temperature, and absolute and relative humidity was analysed. Mean annual growth increment after two years, in both treatments was 12 +/- 1.07% (+/- SE). Growth increment was greatest in winter and lowest in summer; the mean winter growth increment was 6 +/- 0.50%, representing half of the annual growth, whereas most of the remaining growth occurred during both spring and autumn. Growth increments were similar for freely-hanging lichens and for the transplants attached to tree trunks. Individual trees had no consistent effect on growth while the donor thallus had a significant effect in the first season which then diminished, indicating acclimation in the transplants. Initial transplant weight had no influence on final cumulative growth, nor was there any consistent correlation between one season and another in the growth of transplants. Both transplantation methods proved to be useful for experiments on the growth of P. berberina.