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Special Status Plant Species in the Merced River Corridor Within Yosemite National Park on the COVER: Vernal Slab-Seep Community Near Merced Lake

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Special Status Plant Species in the Merced River Corridor Within Yosemite National Park on the COVER: Vernal Slab-Seep Community Near Merced Lake National Park Service U.S. Department of the Interior Natural Resource Program Center Special Status Plant Species in the Merced River Corridor within Yosemite National Park ON THE COVER: Vernal slab-seep community near Merced Lake. Credits: Photo by Dean Taylor Special Status Plant Species of the Merced River Corridor within Yosemite National Park Alison E.L. Colwell, PhD Botanist Resources Management and Science Yosemite National Park 5083 Foresta Road El Portal, CA 95318 and Dean W. Taylor, PhD Consulting Botanist 3212 Redwood Drive Aptos, CA 95003 May 2011 U.S. Department of the Interior National Park Service Yosemite National Park El Portal, California Special Status Plant Species in the Merced River Corridor The National Park Service, Natural Resource Program Center publishes a range of reports that address natu- ral resource topics of interest and applicability to a broad audience in the National Park Service and others in natural resource management, including scientists, conservation and environmental constituencies, and the public. [include one of the following two paragraphs, depending on whether it is an NRR or NRTR report] The Natural Resource Report Series is used to disseminate high-priority, current natural resource management information with managerial application. The series targets a general, diverse audience, and may contain NPS policy considerations or address sensitive issues of management applicability. Or The Natural Resource Technical Report Series is used to disseminate results of scientific studies in the physi- cal, 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 scientifically credible, technically accurate, appropriately written for the intended audience, and designed and published in a professional manner. Peer review manager: choose one or combine and edit multiple pieces from the numbered statements below to best describe the type of peer review performed. The result should be in regular paragraph format and the same font and color as all other text on this page. Make sure to delete this paragraph along with all other unwanted text currently shown in blue italic font. 1. This report received informal peer review by subject-matter experts who were not directly involved in the col- lection, analysis, or reporting of the data. 2. Data in this report were collected and analyzed using methods based on established, peer-reviewed protocols and were analyzed and interpreted within the guidelines of the protocols. 3. This report received formal peer review by subject-matter experts who were not directly involved in the collec- tion, analysis, or reporting of the data, and whose background and expertise put them on par technically and scientifically with the authors of the information. 4. This report received formal, high-level peer review based on the importance of its content, or its potentially con- troversial or precedent-setting nature. Peer review was conducted by highly qualified individuals with subject area technical expertise and was overseen by a peer review manager. Views, statements, findings, conclusions, recommendations, and data in this report do not necessarily reflect views and policies of the National Park Service, U.S. Department of the Interior. Mention of trade names or commercial products does not constitute endorsement or recommendation for use by the U.S. Government. This report is available from Your Network/Division etc. and URL and the Natural Resource Publications Management Web site (http://www.nature.nps.gov/publications/NRPM) on the Internet. Please cite this publication as: Lastname, A., C. Lastname, and D. Lastname. 20XX. Full title of report in sentence case, including subtitle. Natural Resource [Technical] Report NPS/XXXX/NRXX—20XX/XXX. National Park Service, Fort Collins, Colorado. Contains sensitive information: Copying or distributing is prohibited without written agreement from the Division Chief of Resources Management and Science, Yosemite National Park. ii Contents Executive Summary .........................................................................................................................................................................................................v Acknowledgments ..........................................................................................................................................................................................................vi Introduction ......................................................................................................................................................................................................................1 The Drivers of Floristic Diversity and Species Richness in the Region .........................................................................................................1 Study area .....................................................................................................................................................................................................................3 Effect of Past Human Use .........................................................................................................................................................................................3 Effect of Invasive Species on Special Status Plants ..............................................................................................................................................3 Effect of Climate Warming and Nitrogen Input ...................................................................................................................................................4 Methods .............................................................................................................................................................................................................................5 Assessment of Prior Knowledge .............................................................................................................................................................................5 Historical Records Reviewed..............................................................................................................................................................................5 Historic Collections not Relocated ..................................................................................................................................................................6 Survey Methods ..........................................................................................................................................................................................................8 Areas Not Surveyed for This Study ...................................................................................................................................................................9 GPS Data Collection and Analysis .....................................................................................................................................................................9 Map Information ................................................................................................................................................................................................. 10 Location of Data and Specimens .................................................................................................................................................................... 10 Results & Discussion .................................................................................................................................................................................................... 11 Merced Lake ............................................................................................................................................................................................................ 11 Results of Surveys of Merced Lake ................................................................................................................................................................ 11 Discussion of Special Status Species Occurrences ..................................................................................................................................... 11 Notable Trees ................................................................................................................................................................................................. 11 Impacts of Human Activity .......................................................................................................................................................................... 12 Little Yosemite Valley & Vernal Falls ...................................................................................................................................................................... 15 Results of Survey from Merced Lake to Happy Isles.................................................................................................................................. 15 Discussion of Special Status Species Occurrences ....................................................................................................................................
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