Brigham Young University BYU ScholarsArchive Theses and Dissertations 2011-12-16 A Floristic Survey of the Lichens of the Spring Mountains, Nevada, USA Monica W. Proulx Brigham Young University - Provo Follow this and additional works at: https://scholarsarchive.byu.edu/etd Part of the Biology Commons BYU ScholarsArchive Citation Proulx, Monica W., "A Floristic Survey of the Lichens of the Spring Mountains, Nevada, USA" (2011). Theses and Dissertations. 2899. https://scholarsarchive.byu.edu/etd/2899 This Thesis is brought to you for free and open access by BYU ScholarsArchive. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. A Floristic Survey of the Lichens of the Spring Mountains, Nevada, U.S.A. Monica W. Proulx A thesis submitted to the faculty of Brigham Young University in partial fulfillment of the requirements for the degree of Masters of Science Larry L. St. Clair, Chair John Gardner Samuel B. St. Clair Department of Integrative Biology Brigham Young University December 2011 Copyright © 2011 Monica W. Proulx All Rights Reserved i ABSTRACT A Floristic Survey of the Lichens of the Spring Mountains, Nevada, U.S.A. Monica W. Proulx Department of Integrative Biology, BYU Master of Science This thesis is the culmination of a graduate research project involving a floristic survey of the lichens of the Spring Mountain National Recreation Area (SMNRA), Humboldt-Toiyabe National Forest, Nevada. The project was based on extensive collections made between 1997 and 2007 as part of an air pollution biomonitoring program and a baseline established by Larry St. Clair (BYU). The Spring Mountains are a sky island mountain range in the Mojave Desert located less than an hour northwest of Las Vegas. A floristic survey of the lichen communities in the Spring Mountains represents a major addition to our understanding of the lichen flora of the Mojave Desert, a poorly studied region in western North America. This thesis also compares the lichen flora of the SMNRA with other lichen floras of the Mojave Desert based on a literature survey of all the lichen studies conducted in the Mojave Desert. The SMNRA species list represents 58% of the 217 species in 68 genera reported for the Mojave Desert. This survey of all reported Mojave lichen species reveals several interesting interactions related to species diversity, substrate, and growth form distribution patterns. These interactions appear to be influenced by two general factors: Microhabitat conditions and available substrates – which are further defined by differences in geological substrates, occurrence and development of woody plant communities, and a combination of environmental factors – elevation, temperature, precipitation, and insolation. Drier and warmer habitats are generally dominated by crustose species with some, mostly smaller, foliose taxa in protected microhabitats usually with shaded or northern exposures. Fruticose species are generally lacking or sparse with smaller thalli when found in hot and dry habitats. All the fruticose species reported from the Mojave Desert sites were rare and had very small thalli. Many foliose and fruticose species, with larger, more complex thalli and thus greater surface area, are more susceptible to higher rates of water loss and therefore occur less frequently in extreme arid locations. The lichen communities in the Mojave Desert respond to sharp contrasts in microhabitat conditions with exposed, lower elevation sites having lower numbers of species along with more drought resistant growth forms – crustose and squamulose species. The Spring Mountains NRA, with high elevation mountains and well developed woody plant communities, accommodates a large variety of microhabitat conditions spread over a complex temperature and moisture gradient. These conditions have resulted in the highest species diversity (124 species in 48 genera) and the greatest number of foliose and corticolous species when compared with all of the other Mojave Desert lichen floras. Keywords: Air quality, biomonitoring, lichens, Mojave Desert, floristic survey, microhabitat, Spring Mountains National Recreation Area, desert, Las Vegas, air pollution, species diversity ii ACKNOWLEDGMENTS It was a pleasure to prepare a floristic survey based on this extensive and long running collection of lichens from Spring Mountain National Recreation Area, Humboldt-Toiyabe National Forest, Nevada. Collections were made over a 7 year period by Larry L. St. Clair, Samuel B. St. Clair, and Lyndon D. Porter. I would like to thank my advisor, Dr. Larry L. St. Clair for trusting me with this task, for all his help on the thesis and for the years of patience and excellent advice that he has given me, and also my committee members Dr. John Gardner and Dr. Samuel St. Clair for their time, patience, good advice and excellent teaching and Dr. Gardner for his help with the electron microscope. This collection of lichens was over seven years in the making, and took many days, miles and hours and involved a large cast of people, all of whom I would like to thank. Because of their efforts I didn’t have to tromp around for hours in the hot sun or dodge rain or snakes. Additionally I would like to thank all the people who have worked in the BYU lichen lab, they have made this the most congenial place on campus to spend time. Thanks to my fellow students Dr. Steve Leavitt, Gajendra Shrestha, LauraDawn Levitt, Todd Kitchen, and Daniel Leavitt for all the great conversations, and particularly to Steve and Gajendra for excellent advice and genuine friendship, Daniel Leavitt for many hours spent helping to proofread and to Sam Garcia for formatting my thesis. I would like to thank family and friends who have vicariously endured 4 years of work with me. I would particularly like to thank my son Caleb Proulx for his many hours of assistance in transcribing, and my sister and her husband, Valerie and Allen Metscher, for all their support, and my other sons – Joshua, Gabriel, Jonathan, and Benjamin, for believing in me. Finally, I would like to thank my friend Lisbeth Hopper for her help with proofreading. iii Table of Contents List of Tables ................................................................................................................................. vi List of Figures ............................................................................................................................... vii Introduction ..................................................................................................................................... 1 Objectives ................................................................................................................................ 1 Materials and Methods .................................................................................................................... 5 Study Site ................................................................................................................................ 6 Collection Sites: ...................................................................................................................... 8 Site No. 1 ........................................................................................................................ 8 Site No. 2 ........................................................................................................................ 8 Site No. 3 ........................................................................................................................ 8 Site No. 4 ...................................................................................................................... 10 Site No. 5 ...................................................................................................................... 10 Site No. 6 ...................................................................................................................... 11 Site No. 7 ...................................................................................................................... 11 Site No. 8 ...................................................................................................................... 11 Site No. 9 ...................................................................................................................... 11 Site No. 10 .................................................................................................................... 12 Site No. 11 .................................................................................................................... 12 Site No. 12 .................................................................................................................... 12 Site No. 13 .................................................................................................................... 12 Site No. 14 .................................................................................................................... 13 Site No. 15 .................................................................................................................... 13 Results ........................................................................................................................................... 14 Key to Genera and Species .................................................................................................... 19 Fruticose