Forest management practices have changed the over-all structure of the Fennoscandian forest landscape resulting in a lack of suitable substrates for many wood-inhabiting species. The objectives of this thesis was to describe the colonization patterns of wood-inhabiting fungi, including the potential role of beetles as dispersal vectors, on different types of dead wood substrate and assess the importance of active measures in the forest landscape in order to restore biodiversity i.e. to increase the amount of dead wood and the use of restoration fire. The results clearly demonstrate the importance of restoration fire for wood-inhabiting fungi in a dry Pinus sylvestris forest. The general pattern for the majority of the species was a drastic decline the first two years after fire. However, after four years most of the species had recovered and were frequently found on logs strongly affected by the fire. The early fungal colonization patterns on fresh experimental Picea abies logs revealed no differences between managed forest stands and stands associated with nature reserves. After five years the species assemblage on the experimental logs was affected by stand age, forest site type, and distance to forest reserves. However, very few red-listed species colonized the logs in spite of being fairly common in the reserve stands. We conclude that the experimental period of only five years was too short to fully evaluate the possibilities to use experimental logs for threatened and red-listed species. We assessed the colonization patterns of different fungal functional groups based upon their different nutritional strategies namely mycorrhizal, saprotrophic on litter and humus, saprotrophic on wood causing white rot, and saprotrophic on wood causing brown rot. The results show that the fungal community undergoes a marked change in dominant nutritional strategies during the initial stage of the colonization process both after fire disturbance and on fresh un-colonized experimental logs. To which extent, saproxylic beetles are involved as passive or active vectors in the dispersal and colonization of wood-inhabiting fungi occurring on dead wood is poorly understood. The results clearly showed that some beetle species do discriminate between different fungal substrates and in particular, the bark beetle Dryocoetes autographus showed significant preference for wood with Fomitopsis rosea mycelium.

Dead wood is an important part of forest ecosystems, especially since so many organisms depend on it for nutrients or as substrate for breeding or foraging. Since forestry intensified in northern Europe during the mid 1900s, the amount of dead wood in Fennoscandian forests has drastically decreased. For wood-inhabiting organisms such as fungi, this has led to changes in the community composition with many species becoming rare and threatened by extinction. To increase the volume of dead wood, restoration actions aim to create dead wood artificially by for example prescribed burning or by ring-barking trees. In coniferous forests, artificially created dead wood is known to be colonized by many wood-inhabiting fungi, indicating that it can work as a substitute of naturally dead wood. There is, however, a shortage for similar studies in deciduous forests and especially birch dominated ones. In this study, we examine the wood-inhabiting fungal community composition on standing dead wood of birches in east central Sweden. Data was collected with single surveys of fruitbody presence on both ringbarked and naturally dead trees during late autumn. We found that there is a difference in the fungal community composition between the dead wood categories, with form groups of Corticoids and Pyrenomycetes being significantly more abundant on ring-barked birches thanon naturally dead birches. This includes species such as Stereum rugosum and Jackrogersella multiformis. A total of 41 fungal species were observed in this study, out of which 30 species were observed on ringbarked trees and 31 species observed on naturally dead trees. The most observed species was Fomes fomentarius, which appeared numerously on trees of both deadwood categories. Our results indicated that the presence of Fomes fomentarius correlate with lower foraging activity of woodpeckers. However, further research is needed to evaluate if fungal species can be used as indicators for successful restoration actions in relation to the activity of insects and foraging woodpeckers. We conclude that ring-barked birches work well as suitable substrate for many fungal species and that ring-barking as a restoration action is useful for the community of wood-inhabiting fungi.

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