| Summary: | Movement has become a very active topic in biological research. An area of particular interest is identifying traits that determine species movement patterns and that could be used to predict their population trends in the changing world. Wood decay fungi have become one of the great losers in the human-dominated forest landscape of Fennoscandia today. Many species are threatened by the loss and fragmentation of old-growth forest and the decline of dead wood in production forests. However, other species have not been affected and some even seem to benefit from fragmentation. In this doctoral thesis, I combine empirical and modelling approaches to uncover the traits that determine dispersal ability in wood decay fungi. I examine the possibility of dispersal limitation and assess whether species responses to habitat fragmentation are related to their dispersal ability. My results confirm that wood decay fungi have a very high dispersal potential. Even under moderate wind conditions, as much as 95% of the spores released by a fruit body can disperse beyond 1 km. Spores that are lifted above the forest canopy join the atmospheric spore pool that can extend around the world. Nevertheless, spore concentration is rapidly diluted with increasing distance from the source. Due to this distance-dependence and the rarity of colonisation opportunities, wood decay fungi that are rare in the landscape and have specialised resource requirements are likely to be dispersal limited already at the scale of hundreds of metres. Wood decay species differ in a number of dispersal-related traits, creating differences in species dispersal patterns. Spore size is particularly important as it determines spore deposition rate from the air to surfaces: small spores disperse considerably further than large spores. However, the declined species are not generally less efficient dispersers than other species. Substrate availability combined with establishment probability is likely to be more critical for species persistence than dispersal ...
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