Lichen communities and caribou habitat in Denali National Park and Preserve, Alaska, USA

• Main Author: Nelson, Peter R.
• Other Authors: McCune, Bruce, Taylor, Barbara, McComb, Brenda, Cohen, Warren, Pyke, Dave, Botany and Plant Pathology, Oregon State University. Graduate School
• Format: Doctoral or Postdoctoral Thesis
• Language: English; unknown
• Published: Oregon State University
• Subjects: Caribou > Food > Alaska > Denali National Park and Preserve; Lichens > Effect of fires on > Alaska > Denali National Park and Preserve; Lichen communities > Alaska > Denali National Park and Preserve; Lichens > Remote sensing > Alaska > Denali National Park and Preserve; Caribou > Habitat > Alaska > Denali National Park and Preserve; Lichens > Climatic factors > Alaska > Denali National Park and Preserve; Lichens > Ecophysiology > Alaska > Denali National Park and Preserve; Subarctic; Alaska
• Online Access: https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/7s75dg562

Lichens play many important roles in subarctic terrestrial ecosystems by fixing nitrogen, colonizing rock and gravel, stabilizing otherwise bare soil, adding significantly to vegetation biodiversity and serving as the primary food for caribou in the winter. In these chapters, I analyzed lichen community and ecological trait structure along environmental gradients, map lichens using some of their unique spectral properties to generate lichen maps and study caribou habitat selection patterns in relation to lichens and other habitat variables. Morphological and life history traits of lichens influence their ecological roles through physiological limitations imposed by their form and photobionts, the algal or cyanobacterial partner. In chapter 2, I analyzed the lichen traits in relationship to environmental gradients, other forms of vegetation and time since fire in Denali National Park and Preserve, Alaska. Lichens with different photobionts reached different maxima along environmental gradients, these corresponding to variable water availability or specific biotic factors thought to favor that photobiont. Green algal lichens were most abundant in the alpine whereas cyanolichens peaked where shrub cover increased. Tripartite lichens were most abundant in middle elevation, mossy areas. Lichen growthforms peaked along desiccation and water absorption gradients. Lichens with small vegetative propagules were most abundant in lowland forests. Recent fire favored simple, Cladonia-form lichens with soredia that grow on wood whereas erect branched fruticose lichens, the "reindeer lichens", had only partially recovered 20-100 years after fire. These results imply interacting forces of water regulation, dispersal and optimum conditions for photosynthesis drive lichen trait frequency and abundance. The fungal partner within the lichen symbiosis produces many unique compounds that are often brightly colored. Other studies have attempted to map lichens using their distinctive spectral properties but no study has yet to target ...