Getting to know our biomonitor neighbours: urban lichens and allied fungi of Edmonton, Alberta, Canada

Here we provide one of the first detailed studies of lichen and allied fungi diversity in a continental North American city (Edmonton, Alberta, Canada), including an annotated checklist, images of all species, dichotomous keys, and local distribution maps. Edmonton is the northernmost city in North America with a population of over one million, and an industrial and transportation gateway for much of northern Canada. Lichen-based biomonitoring could be a tool to track airborne pollutants resulting from Edmonton’s growing populace and industrial activity. The first step towards such a program is documenting the diversity and distribution of lichens in the city. To accomplish this, we conducted a city-wide, systematic survey of 191 sites focused on epiphytes growing on deciduous boulevard trees. We augmented that survey with surveys of rare trees, opportunistic collections from river valley and ravine habitats, herbarium collections, phylogenetic analyses of a subset of collections, and observations submitted to online nature-reporting applications. We present ITS sequence barcode data for 33 species, phylogenetic analyses for Candelariaceae, Endocarpon, Flavopunctelia, the Lecanora dispersa group, Lecidella, Peltigera, Physconia, and Punctelia, and detailed descriptions of 114 species in 47 genera and 23 families. Two species are hypothesized to be new to North America (Endocarpon aff. unifoliatum, Lecidella albida), twelve more are new to Alberta (Amandinea dakotensis, Bacidia circumspecta, Candelaria pacifica, Candelariella antennaria, Heterodermia japonica, Lecania naegelii, Lecanora sambuci, Lecanora stanislai, Lecidea erythrophaea, Peltigera islandica, Phaeocalicium aff. tremulicola, and the introduced Xanthoria parietina), and five are putative new species to science (Physcia aff. dimidiata, Physcia aff. stellaris, Phaeocalicium sp., Phaeocalicium aff. tremulicola, Lichenaceae sp.). Illustrations are provided for all species to aid in verification and public outreach. Species richness was highest in foliose lichens (48), followed by crustose and calicioid lichens and allied fungi (41), with the lowest richness in fruticose lichens (25). We did a preliminary assessment of the suitability of species for citizen-science biomonitoring by assessing their distribution across the city, perceptibility to the public, identification accuracy, and, for a subset, how consistently species were surveyed by trained novices. Compared to other urban areas where lichen diversity has been studied, Edmonton is relatively species-rich in calicioids and Peltigera. Promising bioindicators may be limited to chlorolichens, including Caloplaca spp., Evernia mesomorpha, Flavopunctelia spp., Phaeophyscia orbicularis, Physcia adscendens, Physcia aipolia group, Physcia aff. stellaris, Usnea spp., and Xanthomendoza fallax. Other genera that may be responsive to pollutants such as Cladonia and Peltigera were almost exclusively restricted to river valley and ravine ecosystems, limiting their application as bioindicators. Some species commonly used as biomonitors elsewhere were too rare, small, poorly developed, or obscured by more common species locally (e.g., Candelaria concolor s.l., Xanthomendoza hasseana). The low overlap with lists of biomonitoring species from other regions of North America illustrates the necessity of grounding monitoring in knowledge of local diversity. Future augmentation of this list should focus on enhanced sampling of downed wood-, conifer-, and rock-dwelling lichens, particularly crustose species. The next step in developing a biomonitoring program will require modelling species’ responses to known air quality and climatic gradients.