Human-induced fragmentation affects forest continuity, i.e. availability
of a suitable habitat for the target species over a time period. The dependence of wood-inhabiting fungi on
landscape level continuity has been well demonstrated, but the importance of
local continuity has remained controversial. In this study, we explored the
effects of local forest continuity (microhabitat and stand level) on the diversity
of wood-inhabiting fungi on standing dead trunks of Scots pine (Pinus sylvestris L.). We studied species richness and community composition of decomposers
and Micarea lichens on 70 trunks in
14 forests in central Finland that differed in their state of continuity. We
used dendrochronological methods to assess the detailed history of each study
trunk, i.e. the microhabitat continuity. The stand continuity was estimated as
dead wood diversity and past management intensity (number of stumps). We
recorded 107 species (91 decomposers, 16 Micarea
lichens), with a total of 510 occurrences. Using generalized linear mixed
models, we found that none of the variables explained decomposer species
richness, but that Micarea species
richness was positively dependent on the time since tree death. Dead wood
diversity was the most important variable determining the composition of decomposer
communities. For Micarea lichens, the
community composition was best explained by the combined effect of years from
death, site and dead wood diversity. However, these effects were rather
tentative. The results are in line with those of previous studies suggesting
the restricted significance of local forest continuity for wood-inhabiting
fungi. However, standing dead pines that have been available continuously over
long periods seem to be important for species-rich communities of Micarea lichens. Rare specialists (e.g. on veteran trees) may be more sensitive to local
continuity, and should be at the center of future research.