Jung, N.J., H.N. Eyster and K.M.A. Chan “Re-envisioning urban landscapes: lichens, liverworts, and mosses coexist spontaneously with us.” Frontiers in Ecology and the Environment n/a(n/a): e2836. Doi: 10.1002/fee.2836
Current conceptions of “urban biodiversity” address only particular taxa, ignoring the full richness of species within cities. Despite their exclusion from these conceptions, tree-dwelling lichens, mosses, and liverworts (collectively, “epiphytes”) are recognized as bioindicators of urbanization, but their inherent contributions to biodiversity are largely unrecognized. Here, we report on a survey of epiphytes in the city of Vancouver, Canada. Using Bayesian multilevel models, we asked the following questions: how diverse are epiphytes in this large temperate city, and what urban and host-tree factors determine their distribution? We found 39 macrolichen, 32 moss, and seven liverwort species on Vancouver street trees, establishing them as rich microenvironments influenced by a network of interacting factors previously unaccounted for. Our results challenge the idea that pollution and urban heat islands primarily regulate urban epiphyte diversity; instead, we identify host-tree genus as having strong effects on all epiphytes. Expanding urban biodiversity to include epiphyte diversity recharacterizes urban landscapes as rewilded spaces of interdependent coexistence.