Dispersal of Phlebia centrifuga, a wood-rotting fungus specialized on old-growth forests

Reijo Penttilä, Research Centre of Friendship Park, Kuhmo and University of Helsinki
Paula Siitonen, Finnish Environment Institute
Kari Korhonen, Timo Kurkela and Sanna Kannelsuo, Finnish Forest Research Institute
Erkki Rantakrans and Risto Pesonen, Finnish Meteorological Institute

Dispersal and spore production of the wood-rotting fungus Phlebia centrifuga was studied to develop a model to predict dispersal of the species in a fragmented forest landscape.

Dispersal and germination of P. centrifuga spores was studied in the field. Wind-disseminated spores were captured by agar-plates containing haploid mycelia of the species. Agar-plates were placed at 4-8 different directions and at different distances (0.5-1024 m) from an isolated site of the species. Later on the plates were analyzed for an occurrence of diploid mycelia, which indicates that a spore/spores of the studied species had landed and germinated on the plate.

Results indicate that dispersal dispersal of P. centrifuga is strongly concentrated in the close vicinity of the fruitbody. Chances to colonice a remote log from an isolated site semm to be very low, since in experiments we found spores only from two out of over 1000 agar-plates (57 cm2 each) placed at 256, 512 and 1024 meters away from the fruitbody of P. centrifuga.

Spore production was studied by using a volumetric spore trap taking discrete spore prints and a simple spore trap counting the total numbers of spores released from a fruitbody before and after every dispersal experiment. The maximum value of produced spores before or after every dispersal experiments was about 30 000 spores/cm2 of fertile hymenia/1 hour (mean=8500) and the approximated maximal numbers of spores produced by the fruitbody (990-1130 cm2 in size) was over 30 million spores per hour (mean=9 600 000).

Fig.1. Dispersal of Phlebia centrifuga at different directions and distances from an isolated site of the species. Size of the circle indicate the proportion (%) of spore-containing agar-plates from all agar-plates (biggest circle is 100% and line is 0%). In experiments(1-8 at different directions) one agar-plate was placed at distances 0.5-16 meters and six agar-plates at distances 32-1024 meters.