A Vegetation Management Plan for Fort Union Trading Post National Historic Site Final Report for Interagency Agreement Number F1549100005 (April 2012)
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National Park Service U.S. Department of the Interior Natural Resource Stewardship and Science A Vegetation Management Plan for Fort Union Trading Post National Historic Site Final Report for Interagency Agreement Number F1549100005 (April 2012) Natural Resource Report NPS/FOUS/NRR—2012/502 ON THE COVER Field 7 at Fort Union Trading Post National Historic Site Photograph by: Amy Symstad A Vegetation Management Plan for Fort Union Trading Post National Historic Site Final Report for Interagency Agreement Number F1549100005 (April 2012) Natural Resource Report NPS/FOUS/NRR—2012/502 Amy J. Symstad U.S. Geological Survey Northern Prairie Wildlife Research Center Wind Cave National Park 26611 U.S. Highway 385 Hot Springs, SD 57747 April 2012 U.S. Department of the Interior National Park Service Natural Resource Stewardship and Science Fort Collins, Colorado The National Park Service, Natural Resource Stewardship and Science office in Fort Collins, Colorado 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 natural resource management, including scientists, conservation and environmental constituencies, and the public. 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. 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. This report received formal, high-level peer review based on the importance of its content, or its potentially controversial 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 the Superintendent, Fort Union Trading Post National Historic Site (http://www.nps.gov/fous/contacts.html) and the Natural Resource Publications Management website (http://www.nature.nps.gov/publications/nrpm/). Please cite this publication as: Symstad, A. J. 2012. A vegetation management plan for Fort Union Trading Post National Historic Site: Final report for interagency agreement number F154910005 (April 2012). Natural Resource Report NPS/FOUS/NRR—2012/502. National Park Service, Fort Collins, Colorado. NPS 436/113441, April 2012 ii Contents Page Figures........................................................................................................................................... vii Tables ............................................................................................................................................. ix Appendices ..................................................................................................................................... xi Executive Summary ..................................................................................................................... xiii Acknowledgments......................................................................................................................... xv Introduction ..................................................................................................................................... 1 Vegetation of Fort Union Trading Post National Historic Site....................................................... 3 Factors that Shaped the Native Vegetation .............................................................................. 3 Historic Vegetation, 1800 - 1867 ............................................................................................. 6 Historic Information ........................................................................................................... 6 National Vegetation Classification System Descriptions for Floodplain Vegetation ........................................................................................................................... 8 Ecological Site Descriptions for Upland Areas ................................................................ 10 Caveats about These Descriptions .................................................................................... 12 Factors Affecting FOUS Vegetation, 1867-1966 .................................................................. 13 Vegetation Management since NPS Acquisition, 1966-2010 ............................................... 14 Riparian Floodplain.......................................................................................................... 15 Upland Terraces – North Side of River ............................................................................ 16 Upland Terraces – South Side of River............................................................................. 26 Bodmer Overlook Unit ...................................................................................................... 26 Current Vegetation at FOUS ................................................................................................. 27 Vegetation Map ................................................................................................................. 27 Floristic Inventory ............................................................................................................ 29 iii Contents (continued) Page Certified Species List ........................................................................................................ 30 Field Data ......................................................................................................................... 30 Conservation Status of Vegetation Associations and Species........................................... 36 Summary and Evaluation of Historic and Current Vegetation and Management at FOUS ..................................................................................................................................... 36 Desired Conditions for the Vegetation of FOUS .......................................................................... 41 Guidelines for Determining Desired Conditions ................................................................... 41 Process for Determining Desired Conditions ....................................................................... 41 Desired Conditions ................................................................................................................ 43 Upland Terraces Surrounding the Fort ............................................................................ 43 Hill Tops and Upper Slopes in the Bodmer Overlook Unit .............................................. 43 Lower Slopes and Valleys in the Bodmer Overlook Unit ................................................. 44 Riparian Floodplain North of the Missouri River ............................................................ 44 Terraces South of the Missouri River ............................................................................... 44 Current Departure from Desired Conditions ................................................................... 44 Exotic Plants and Vegetation Management Tools ........................................................................ 45 Exotic Plants .......................................................................................................................... 45 Exotic, Invasive, and Noxious Plants Documented at FOUS ........................................... 45 Past and Current Exotic Plant Management .................................................................... 49 Continuing Exotic Plant Management .............................................................................. 50 Management Tools ................................................................................................................ 55 Preventative Measures ...................................................................................................... 55 Planting ............................................................................................................................. 56 Manual and Mechanical Methods .................................................................................... 61 iv Contents (continued) Page Prescribed Fire ................................................................................................................. 62 Grazing ............................................................................................................................. 63 Monitoring, Adaptive Management, Record-Keeping, and Evaluation ....................................... 65 Upland Terraces Surrounding the Fort .................................................................................. 67 Bodmer Overlook Unit .......................................................................................................... 69 Riparian Floodplain North of the Missouri River .................................................................. 70 Terraces