Life Sciences Commons^™

Lichens Of Ultramafic Rocks: A Multidisciplinary Approach To Understanding The Ecology Of An Understudied Organism In A Well-Studied System, Michael Mulroy

Master's Theses

Lichens are among the most prominent and successful life forms of metal-rich habitats, including ultramafic rocks and soils; however, research on lichens of ultramafic habitats is limited, especially on the North American continent. A review of the published literature on lichens of ultramafic substrates in North America yielded a total of 437 lichen species reported from ultramafic rocks and soils. Lichen assemblages of ultramafic substrates vary in composition and are dominated by acidophytic (low pH preferring) taxa with a minor, but consistent, basiphytic (high pH preferring) component. Species lists from ultramafic habitats in different geographic regions varied widely, suggesting that …

Additional Lichen Records And Mineralogical Data From Metal-Contaminated Sites In Maine, Ian D. Medeiros, Alan M. Fryday, N. Rajakaruna

Biological Sciences

Geochemistry and mineralogy of rocks play important roles in the occurrence of individual lichen species and assembly of lichen communities. Whereas lichens of metal-enriched settings have been a focus of study for many decades, only a few such lichen inventories exist for North America. We reexamined the lichen biota of Pine Hill, a serpentine outcrop on Little Deer Isle, Maine and Callahan Mine, a copper-and zinc-enriched Superfund site in Brooksville, Maine by conducting additional field surveys and reexamining unidentified taxa from previous collections. To better characterize the substrates upon which the lichens were found, we conducted elemental analyses via x-ray …

Edaphic Adaptation Maintains The Coexistence Of Two Cryptic Species On Serpentine Soils, Jenn M. Yost, Teri Barry, Kathleen M. Kay, Nishanta Rajakaruna

Biological Sciences

• Premise of the study: Divergent edaphic adaptation can contribute to reproductive isolation and coexistence between closely related species, yet we know little about how small-scale continuous edaphic gradients contribute to this phenomenon. We investigated edaphic adaptation between two cryptic species of California wildflower, Lasthenia californica and L. gracilis (Asteraceae), which grow in close parapatry on serpentine soil.

• Methods: We reciprocally transplanted both species into the center of each species’ habitat and the transition zone between species. We quantified multiple components of fitness and used aster models to predict fitness based on environmental variables. We sampled soil across the …