National Park Service U.S. Department of the Interior Natural Resource Program Center Vascular Plant Inventory of Glen Canyon National Recreation Area Natural Resource Technical Report NPS/SCPN/NRTR—2009/264 ON THE COVER Glen Canyon National Recreation Area near 40-mile Ridge Photo: Jim DeCoster Vascular Plant Inventory of Glen Canyon National Recreation Area Natural Resource Technical Report NPS/SCPN/NRTR—2009/264 Authors Mar-Elise Hill Arizona Western College Yuma Arizona 85364 Tina Ayers Northern Arizona University Flagstaff, Arizona 86004 Editing and Layout Jean Palumbo Northern Arizona University Flagstaff, Arizona 86004 November 2009 U.S. Department of the Interior National Park Service Natural Resource Program Center Fort Collins, Colorado The National Park Service, Natural Resource Program Center publishes a range of reports that address natural resource topics of interest and applicability to a broad audience in the National Park Service and others in natu- ral resource management, including scientists, conservation and environmental constituencies, and the public. The Natural Resource Technical Report Series is used to disseminate results of scientific studies in the physical, biological, and social sciences for both the advancement of science and the achievement of the National Park Service mission. The series provides contributors with a forum for displaying comprehensive data that are often deleted from journals because of page limitations. All manuscripts in the series receive the appropriate level of peer review to ensure that the information is scientif- ically credible, technically accurate, appropriately written for the intended audience, and designed and published in a professional manner. Views, statements, findings, conclusions, recommendations, and data in this report are those of the author(s) and do not necessarily reflect views and policies of the National Park Service, U.S. Department of the Interior. Men- tion of trade names or commercial products does not constitute endorsement or recommendation for use by the National Park Service. This project was funded by the National Park Service through the Colorado Plateau CESU Cooperative Agreement #1200-99-009 (Task NAU-143). The report is available from the Southern Colorado Plateau Network website (http://www.nature.nps.gov/im/units/SCPN), and the Natural Resource Publications Management Web site (http://www.nature.nps.gov/publications/NRPM) on the Internet. Please cite this publication as: Hill, M. E., and T. Ayers. 2009. Vascular plant inventory of Glen Canyon National Recreation Area. Natural Resource Technical Report NPS/SCPN/NRTR—2009/264. National Park Service, Fort Collins, Colorado. NPS 608/100619, November 2009 ii Contents Figures ........................................................................................................................................................... v Tables ............................................................................................................................................................. v Abstract ........................................................................................................................................................ ix Acknowledgments ....................................................................................................................................... xi 1 Introduction ..............................................................................................................................................1 2 Background ...............................................................................................................................................1 2.1 Landscape description ...................................................................................................................1 2.2 Previous work ................................................................................................................................1 2.3 Climate ...........................................................................................................................................2 2.4 Vegetation Communities ..............................................................................................................4 2.5 Notable Plant Species ....................................................................................................................5 2.6 Geology ..........................................................................................................................................9 3 Methods ...................................................................................................................................................10 3.1 Sampling methods .......................................................................................................................10 3.2 Herbarium searches .....................................................................................................................11 3.3 Floristic Composition ...................................................................................................................11 3.4 Vegetation Communities ............................................................................................................11 3.5 Pre/Post Glen Canyon Dam Floras...............................................................................................12 4 Results ......................................................................................................................................................12 4.1 Vascular Flora ...............................................................................................................................12 4.2 Floristic Composition ...................................................................................................................14 4.3 Vegetation Communities ............................................................................................................15 4.4 Pre/Post Glen Canyon Dam Floras...............................................................................................16 5 Discussion .................................................................................................................................................16 5.1 Vascular Flora ...............................................................................................................................16 5.2 Floristic Composition ...................................................................................................................19 5.3 Vegetation Communities ............................................................................................................19 5.4 Pre-/Post-Glen Canyon dam floras ..............................................................................................21 5.5 Recommendations for future floristic exploration ...................................................................21 6 Literature Cited .......................................................................................................................................22 Appendix A: Catalog of the Vascular Plants of Glen Canyon NRA, Arizona and Utah ..................... A1 Appendix B: List of Reported, But Unvouchered, Vascular Plants of Glen Canyon NRA.. ................B1 Appendix C: Plants Extirpated From Glen Canyon NRA After the Completion of Glen Canyon Dam ......................................................................................................................................C1 Appendix D: Names and Acronyms of Southern Colorado Plateau Network Parks .........................D1 Appendix E: Sensitive Species .....................................................................................................................E1 Contents iii Vascular Plant Inventory of Glen Canyon National Recreation Area Figures Figure 1. Glen Canyon NRA, Lake Powell, and the Colorado River......................................................... 1 Figure 2. Seasonal precipitation for Glen Canyon NRA (in inches). ........................................................3 Figure 3. Average Annual Precipitation (1928-2004) for Glen Canyon NRA (in inches). .......................3 Figure 4. Average Monthly Max and Min Temperatures (1928-2004) for Glen Canyon NRA (in degrees Fahrenheit)....................................................................................................................4 Figure 5: Major Vegetation Types in Glen Canyon NRA...........................................................................7 Figure 6. Glen Canyon NRA Geologic Column........................................................................................10 Figure 7. Number of genera and species in the ten best-represented flora families in Glen Canyon NRA...............................................................................................................................13 Figure 8. Composition of flora at Glen Canyon NRA by life form. .......................................................13 Figure 9. Most species-rich families for parks on the Colorado Plateau...............................................20 Tables Table 1. Past floristic work in Glen Canyon NRA ...................................................................................... 2 Table 2. List of Colorado Plateau endemic plants in Glen Canyon NRA with their associated ecology and global ranks ..........................................................................................................................