Diversity and floristic patterns of epiphytic macrolichens on white oak in the Klamath-Siskiyou region

Abstract

pdf effectively published online 1June2018 via (http://sweetgum.nybg.org/philolichenum/) Diversity and floristic patterns of epiphytic macrolichens on white oak in the Klamath-Siskiyou region JOHN VILLELLA!*, TOM CARLBERG?, DAPHNE STONE?, JESSE E.D. MILLER*, NILS NELSON? AND LALITA CALABRIA ABSTRACT.-White oak (Quercus garryana) plant communities are one of the most threatened habitat types in the Pacific Northwest, and often host diverse and characteristic epiphyte communities. In order to better understand the diversity and floristic patterns of epiphytic macrolichens of these habitats in the Klamath-Siskiyou region we studied lichen communities in 52 plots within the Cascade-Siskiyou National Monument (CSNM). We report a rich flora of 96 species of epiphytes on Quercus garryana. Macrolichen species richness in the plots ranged between 12 and 49 species with an average of 24.7 species per plot. The most species-rich genera in descending order were: Usnea, Physconia, Physcia, Hypogymnia, Melanohalea, Peltigera, Bryoria, Lobaria and Scytinium. We found three rare species that are listed by the Oregon Biodiversity Information Center: Hypotrachyna revoluta (S3-vulnerable), Collema curtisporum (S1-critically imperiled), and Rostania quadrifida (S2-imperiled). Placidium fingens was recorded for the first time as an epiphyte in Oregon. We observed floristic patterns that indicate a mix of lichens from six distinct geographic floristic groups. Of these, the California Madrean floristic group had the fewest representative species but nonetheless included a number of species rare in Oregon such as Melanelixia californica, Physconia californica and P. fallax. We discuss how these new findings influence our current knowledge of oak lichen communities and dispersal corridors within the Klamath-Siskiyou region.KEYWORDS. -California flora, biogeography, biodiversity, Siskiyou crest, woodlands, land bridge, Klamath River 'JOHN VILLELLA*