Many lichen species have specific environmental requirements for colonization. Old-growth forests contain microhabitats required by a particular suite of lichens. In Ontario, Canada, old-growth forests are increasingly uncommon and the lichen communities within some of these forests are not well known. To better understand the lichen communities that inhabit old-growth forests in the province, we examined the lichen biota on coarse woody debris (CWD) and trees in a red pine (Pinus resinosa) and a white pine (Pinus strobus) dominated stand in northern Ontario. Lichen diversity was assessed on different forms of CWD and trees in each forest. Lichen diversity did not differ significantly between CWD types in the red pine forest, but was significantly different in the white pine forest. There was no significant difference in lichen diversity amongst different decay stages of CWD in either forest. In both forests, lichen communities on stumps, logs, and snags differed from lichen communities present on trees. A variety of CWD types is important for overall lichen species richness in the red pine forest. Our results demonstrate to land managers that different types of old-growth forests are ecologically unique, even those dominated by tree species in the same genus. Management of an old-growth forest should suit its individual ecology.
Pollution control initiatives in Greater Sudbury, Ontario, Canada, resulted in the decommissioning of the Coniston Smelter in 1972. The last assessment of the effects from the smelter on the surrounding lichen biota was in 1990, which showed an overall improvement in richness following these initiatives, but still few species were present close to the smelter. We examined five sites along this gradient to determine if this pattern is still present on the landscape. Sixty-four macrolichen species in 15 genera were found. Lichen richness and Shannon diversity increased at all sites, but the increase was no longer linear with distance from the smelter. There was no significant difference between lichen richness and diversity at sites at increasing distances from the smelter. We show that past air pollution from the Coniston Smelter is no longer restricting lichen growth and development in the Greater Sudbury area as it was historically. Lichen populations are, therefore, now shaped by other environmental variables.
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