Graduation Date

Spring 2023

Document Type



Master of Science degree with a major in Biology

Committee Chair Name

Terry Henkel

Committee Chair Affiliation

HSU Faculty or Staff

Second Committee Member Name

Marie Antoine

Second Committee Member Affiliation

HSU Faculty or Staff

Third Committee Member Name

Erik Jules

Third Committee Member Affiliation

HSU Faculty or Staff

Fourth Committee Member Name

Heidi Rutschow

Fourth Committee Member Affiliation

HSU Faculty or Staff

Fifth Committee Member Name

Bruce McCune

Fifth Committee Member Affiliation

Community Member or Outside Professional


Cupressaceae, Biodiversity, Lichens, Lichen biota, Nonmetric multidimensional scaling, Pacific Northwest, Pinaceae, Quercus, Ultramafic rock

Subject Categories



Macrolichen diversity and community composition was determined for an area of high botanical interest in the Coast Ranges of Northern California – the Horse Mountain Botanical Area (HMBA) in Six Rivers National Forest. The Coast Ranges have been suggested to have high epiphytic macrolichen diversity, yet detailed site-specific macrolichen surveys are lacking for the area. Here we present comprehensive data on macrolichens of the HMBA integrated with environmental metadata at the landscape level. Twenty 0.4 ha sampling plots were positioned across the varying habitats of the HMBA and macrolichens were intensively sampled from all substrata. Out of 888 total collections, 119 macrolichen species in 52 genera were identified, sequenced for the mycobiont internal transcribed spacer (ITS) region, and vouchered. Microenvironmental influences on lichen community composition were ordinated with nonmetric multidimensional scaling (NMS). Within-plot measured environmental variables correlated to ordination Axis 1 were 1) total tree basal area, 2) proportion of conifer basal area relative to hardwoods, and 3) distance between plot center and nearest stream. Distinct macrolichen communities were found in plots containing primarily conifers versus mixed hardwood-conifer plots. Total abundances of species with particular functional traits were calculated to enhance plot metadata. When epiphytic macrolichen species richness and dominance within the HMBA were compared to data from other regional National Forest plots, the HMBA showed comparable community composition but higher species richness. An annotated species checklist from this study can help inform management of the HMBA as well as future taxonomic and ecological research on regional macrolichens.

Citation Style




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