Lichen communities along a pollution gradient 40 years after decommissioning of a Cu-Ni smelter

Abstract

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.

Relationships between air pollution, population density, and lichen biodiversity in the Niagara Escarpment World Biosphere Reserve

“…For example, in Rome, Munzi et al (2007) observed an increase in lichen biodiversity along an urban-rural gradient and linked this to concentrations of CO, NO x and SO 2 . In the greater Sudbury area, a reduction in SO 2 pollution resulted in an increase in the region’s lichen diversity (Schram et al 2015). The presence of pollution-sensitive lichens, such as cyanolichens (Richardson & Cameron 2004), can indicate better air quality, as evidenced by the occurrence of the only cyanolichens in our study ( Peltigera praetextata and P. elisabethae ) in the site associated with the lowest population density and lowest level of pollution (Owen Sound rural).…”