Additions to the lichens, allied fungi, and lichenicolous fungi of the Ottawa region in Ontario and Quebec, with reflections on a changing biota

The inventory of lichens, allied fungi, and their parasites in the Ottawa region has grown from 391 in 1988 to 543 today, almost entirely because of the discovery of species overlooked in previous years and the inclusion of fungal parasites. In addition, almost 140 names have changed with reclassifications and re-identifications. These changes are presented here together with a list of synonyms updating the 1988 list. Vouchers are cited for all new records, and notes are presented for many species neither described nor keyed out in easily accessible literature. Reference is made to the new, complete list of lichens and lichenicolous fungi available online. The new checklist includes one species new for North America (Tremella christiansenii); five species and one variety new for Canada (Caloplaca parvula, Caloplaca reptans, Cladonia petrophila, Enchylium tenax var. ceranoides, Leprocaulon adhaerens, and Merismatium peregrinum); four new for Ontario (Caloplaca reptans, Kiliasia tristis, Lempholemma chalazanum, and Rinodina fimbriata); and nine new for Quebec (Arthonia helvola, Arthonia hypobela, Caloplaca parvula, Cladonia petrophila, Lempholemma chalazanum, Leprocaulon adhaerens, Merismatium peregrinum, Rimularia badioatra, and Tremella christiansenii). Although the climate of the region is warming, especially with higher minimum temperatures in winter, the lichen biota has not increased as a result but, in fact, may be threatened by the effects of climate change on the health of the forests and the trees that support lichens. Air quality has improved in recent decades, allowing numerous lichens to again become established in urban areas. Local areas of especially rich lichen diversity can be found on both the Ontario and Quebec sides of the region, and some of these “hot-spots” are mentioned. Other factors influencing the decrease or increase of lichen cover are also discussed.