Abstract:
The Fynbos Biome in the Core Cape Subregion of South Africa is prone to recurrent fires that
can clear vast areas of vegetation. Between periods of fire, ophiostomatoid fungi colonize the
fruiting structures of serotinous Protea species through arthropod-mediated dispersal. Using
microsatellite markers, this study considered the process whereby a Protea-associated
ophiostomatoid fungus, Knoxdaviesia proteae, recolonizes a burnt area. The genetic
diversity, composition and structure of fungal populations from young P. repens plants in a
recently burnt area were compared to populations from the adjacent, unburnt Protea
population. The only difference between K. proteae populations from the two areas was
found in the number of private alleles, which was significantly higher in the unburnt
population. The population structure, although weak, indicated that most K. proteae individuals from recently burnt areas originated from the unburnt population. However,
individuals from unsampled source populations were also detected. This, together with the
lack of isolation-by-distance across the landscape, suggested that long-distance dispersal is
important for K. proteae to recolonize burnt areas. Similarly, the high level of gene flow and
low differentiation observed between two distantly separated K. proteae populations also
supported the existence of long-distance dispersal. The genetic cohesiveness of populations
over long distances and the genetic diversity within populations could be attributed to
frequent multiple fungal migration events mediated primarily by arthropods but, potentially,
also by birds.
