FLORISTIC AFFINITIES OF HORSE MOUNTAIN, GROUSE MOUNTAIN, BOARD CAMP MOUNTAIN AND SURROUNDING AREAS, HUMBOLDT COUNTY, CALIFORNIA By Cara Witte Scott A Thesis Presented to The Faculty of Humboldt State University In Partial Fulfillment of the Requirements for the Degree Master of Arts In Biology December 2010 FLORISTIC AFFINITIES OF HORSE MOUNTAIN, GROUSE MOUNTAIN, BOARD CAMP MOUNTAIN AND SURROUNDING AREAS, HUMBOLDT COUNTY, CALIFORNIA By Cara Witte Scott Approved by the Master’s Thesis Committee: Dr. Michael R. Mesler, Major Professor Date Dr. John O. Sawyer, Committee Member Date Dr. Erik S. Jules, Committee Member Date Dr. John O. Reiss, Committee Member Date Dr. Kenneth R. Aalto, Committee Member Date Dr. Michael R. Mesler, Graduate Coordinator Date Jená Burges, Vice Provost Date ABSTRACT Floristic studies are especially timely since habitat loss is increasing dramatically. From the conservation perspective, it is imperative to document the distribution of plant species in areas that are floristically rich. For this study, I conducted a floristic survey along a 20-mile transect in the Horse Mountain, Grouse Mountain and Board Camp Mountain areas of Humboldt County, California. I also determined the phytogeographical affinities of the taxa I found and made comparisons between my flora and 11 other northwest California floras. Additionally, I made a comparison between my flora and the historical collection of Joseph Prince Tracy, a botanist who collected extensively in the same area during the early 1900s. I used an informal stratified sampling regime to cover the different vegetation types within the study area. Five hundred and forty-eight species were identified from 77 vascular plant families, including 18 California Native Plant Society listed taxa and 28 taxa endemic to northwest California. Most had affinities to western North America (273 species) due to the lower elevational position of the study area. One fifth show affinities to the California Floristic Province (124 species, including 23 endemics), and another 17% (96 species, including 5 endemics) had boreal affinities that are found throughout the state’s mountains at higher elevations. Some 56 species are not native to the California. I used ordination and cluster analysis to compare my flora to 11 other northwest California floras. These analyses revealed two main groups: (1) montane floras of the Klamath Region and (2) low and montane elevation floras of both the Klamath Mountains (Old Gasquet Toll iii Road, 58% shared taxa) and Coast Ranges (Lassics and Snow Mountain, both 65% shared taxa). Comparisons between my flora and the Tracy collection found 295 species in common. Of the 439 taxa Tracy documented from the study area and nearby South Fork Mountain, three non-native species were present during his time suggesting an influx of 54 non-native species over the last 60 years. iv ACKNOWLEDGEMENTS First and foremost, I would like to thank my major professor, Michael Mesler, for his support, guidance, and patience through the life of this thesis. Thank you so much for teaching me about the plants of northwest California, spending countless hours verifying taxa, and for teaching me how to write the English language. Your dedication to your students is unending and your enthusiasm is contagious. I am proud to be a member of the “Mesler grad student” club. I would also like to thank my graduate committee members, Drs. Erik Jules, John Reiss, and Ken Aalto for their advice along the way and useful comments on the manuscript. I am extremely grateful for the help of committee member, Dr. John Sawyer, for helping me gain my footing in the early stages of this thesis, teaching me how to categorize the flora into phytogeographical categories, and make sense of a very interesting ordination. It was an honor to work with you. A special thank you to Dr. J.P. Smith who provided me with updated synonymy checklists, helped track down floras for comparison and provided information about J.P. Tracy. Also, a huge thank you to Robin Bencie for moving my collection in and out of driers, freezers, and cabinets, help with identifying difficult taxa, and for being such a great mentor during my career as a graduate student. Thank you also to Sydney Carothers for verifying my Carex specimens, help with identifying difficult taxa, and for providing moral and editorial support. I am indebted to Helen Constantine Shull and Gordon Leppig whose master’s theses I referenced constantly. v This thesis could not have been done without the hard work of my botanical predecessors (and heroes) whose theses and checklists provided a means of comparison: J.P. Tracy, G. Muth, G. Smith, C. Wheeler, J. Kraemer, M. Butler, W. Ferlatte, C. Ground, A. Hobart, D. Gillespie, F. Oettinger, J. Neilson, D. McQuaid, K. Stillman, J. Whipple, L. Heckard, J. Hickman, L. Barker, T. Nelson, and L. Simpson. Your botanical contributions helped make my thesis possible. Thank you to Lisa Hoover, John McRae, and Joshua Read of Six Rivers National Forest for providing collecting permits and general information about the Forest. Ashley Hawkins and David Franklin for help with PC-ORD and lending statistical advice. Thank you also to Jenna Lee, Greg O’Connell and Dr. Dennis Walker who journeyed with me into the depths of Grouse Mountain and Board Camp; and to the University of California/Jepson Herbarium for allowing me to spend time reading J.P. Tracy’s collecting notebooks. Financial assistance was provided by Northern California Botanists and the Humboldt State University Biology Department Master’s Grant. An extra special thank you to my friends and family, especially my parents, for their loving support and never-ending encouragement. Last, but certainly not least, my husband, Michael Scott, who innocently dropped me off at the Library Circle in August 2001 to attend a General Botany class not know what had just begun. You have been by my side along this academic journey, and I thank you for your patience, strength, and support in helping me achieve my goals. vi DEDICATION To my loyal collecting partner, astute field assistant and mountain lion body guard, Buddy Witte Scott. Even though you complained constantly that it was too hot and often bailed on me to chase deer, your companionship in the field was appreciated. Thank you for your commitment to this project. vii TABLE OF CONTENTS ABSTRACT.......................................................................................................................iii
 ACKNOWLEDGEMENTS................................................................................................v
 DEDICATION..................................................................................................................vii
 LIST OF TABLES.............................................................................................................xi
 LIST OF FIGURES..........................................................................................................xii
 INTRODUCTION..............................................................................................................1
 Location and Boundaries........................................................................................2
 Physiography...........................................................................................................2
 Climate....................................................................................................................6
 Geology...................................................................................................................7
 History of Human Impact.....................................................................................10
 Botanical History..................................................................................................12
 Vegetation.............................................................................................................13
 Phytogeography....................................................................................................18
 METHODS.......................................................................................................................20
 Field Methods.......................................................................................................20
 Specimen Identification Procedures.....................................................................21
 Floristic Analyses..................................................................................................24
 Assignment of Phytogeographical Categories..........................................24
 Comparison Between Floras.....................................................................26
 Comparisons with the Tracy collection....................................................28
 viii Taxa Endemic to Northwest California....................................................29
 RESULTS.........................................................................................................................32
 Floristic Analysis..................................................................................................32
 Rare and Uncommon Taxa.......................................................................32
 Range Extensions of Regional Endemics.................................................32
 Northwest California Endemics................................................................35
 Non-native Taxa.......................................................................................35
 Quantitative Analyses...........................................................................................40
 Phytogeographic Elements in My Flora...................................................40
 Comparison among floras.........................................................................41
 Comparison with the Tracy collection......................................................49
 DISCUSSION...................................................................................................................50
 Phytogeographical Origins of the Flora................................................................50
 Western North America............................................................................50
 California Floristic Province.....................................................................52
 Boreal........................................................................................................53
 Non-Native Taxa.......................................................................................54
 Comparisons with Other Floras............................................................................55
 Historical Changes................................................................................................58
 LITERATURE CITED.....................................................................................................63
 APPENDIX A. Annotated species list of Horse Mountain, Grouse Mountain, Board Camp Mountain and surrounding areas.....................................................69 APPENDIX B. Environmental variables used in quantitative analysis……………...…119 APPENDIX C. Similarity matrix.....................................................................................121 ix APPENDIX D. Species list of taxa found by Tracy that I did not find...........................122 x