National Park Service U.S. Department of the Interior Natural Resource Stewardship and Science Natural Resource Condition Assessment Horseshoe Bend National Military Park Natural Resource Report NPS/SECN/NRR—2015/981 ON THE COVER Photo of the Tallapoosa River, viewed from Horseshoe Bend National Military Park Photo Courtesy of Elle Allen Natural Resource Condition Assessment Horseshoe Bend National Military Park Natural Resource Report NPS/SECN/NRR—2015/981 JoAnn M. Burkholder, Elle H. Allen, Stacie Flood, and Carol A. Kinder Center for Applied Aquatic Ecology North Carolina State University 620 Hutton Street, Suite 104 Raleigh, NC 27606 June 2015 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. These reports are 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 comprehensive information and analysis about natural resources and related topics concerning lands managed by the National Park Service. The series supports the advancement of science, informed decision-making, and the achievement of the National Park Service mission. The series also provides a forum for presenting more lengthy results that may not be accepted by publications with 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. This report received formal peer review by subject-matter experts who were not directly involved in the collection, analysis, or reporting of the data, and whose background and expertise put them on par technically and scientifically with the authors of the information. 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 in digital format from the Southeast Coast Inventory & Monitoring Network website (http://science.nature.nps.gov/im/units/secn/index.cfm) and the Natural Resource Publications Management website (http://www.nature.nps.gov/publications/nrpm/). To receive this report in a format optimized for screen readers, please email [email protected]. Please cite this publication as: Burkholder, J. M., E. H. Allen, S. Flood, and C. A. Kinder. 2015. Natural resource condition assessment: Horseshoe Bend National Military Park. Natural Resource Report NPS/SECN/NRR— 2015/981. National Park Service, Fort Collins, Colorado. NPS 407/128933, June 2015 ii Contents Page Figures.................................................................................................................................................. vii Tables .................................................................................................................................................... xi Plates .................................................................................................................................................. xvii Appendices ......................................................................................................................................... xvii Acknowledgments ............................................................................................................................... xix Abbreviations ...................................................................................................................................... xxi Executive Summary ........................................................................................................................... xxv 1. NRCA Background Information .................................................................................................... 1 2. Introduction and Setting ................................................................................................................. 5 2.1. Introduction ........................................................................................................................ 5 2.2. Enabling Legislation and Potential for Expansion ............................................................. 8 2.3. Geographic Setting ............................................................................................................. 8 2.4. Demographics .................................................................................................................. 12 2.5. Visitation Statistics .......................................................................................................... 15 2.6. Watersheds ....................................................................................................................... 16 2.7. GIS Data Layers ............................................................................................................... 18 2.7.1. Data Selection and Acquisition .......................................................................... 18 2.7.2. Data Oversight and Database Management ........................................................ 18 2.7.3. Map Generation .................................................................................................. 19 3. Natural Resources Inventory ........................................................................................................ 21 3.1. Climate ............................................................................................................................. 21 3.1.1. Temperature ........................................................................................................ 23 3.1.2. Precipitation ........................................................................................................ 25 3.1.3. Moisture .............................................................................................................. 27 3.1.4. Phenology (Growing Degree Days).................................................................... 29 3.1.5. Extreme Weather Events .................................................................................... 33 3.2. Air Quality ....................................................................................................................... 36 3.2.1. Federal Criteria for Major Air Pollutants, and a Federal Index Scale ................ 36 iii 3.2.2. National Park Service Indices for Air Quality .................................................... 40 3.2.3. Air Quality in the Park and Vicinity ................................................................... 42 3.3. Soundscape ...................................................................................................................... 50 3.3.1. Some Definitions and Interpretations ................................................................. 50 3.3.2. The Horseshoe Bend Soundscape ....................................................................... 51 3.4. Lightscape ........................................................................................................................ 52 3.5. Geology and Soils ............................................................................................................ 56 3.5.1. Geologic Resources ............................................................................................ 56 3.5.2. Soils and Erosion ................................................................................................ 58 3.6. Water Resources .............................................................................................................. 61 3.6.1. Surface Water ..................................................................................................... 62 3.6.2. Groundwater ....................................................................................................... 84 3.7. Biological Resources and Management ........................................................................... 89 3.7.1. Attributes Used in Assessment ........................................................................... 89 3.7.2. Horseshoe Bend Biota Assessment – Overview ................................................. 91 3.7.3. Vascular Flora ..................................................................................................... 95 3.7.4. Fish ..................................................................................................................... 99 3.7.5. Herpetofauna .................................................................................................... 101 3.7.6. Birds.................................................................................................................. 106 3.7.7. Mammals .......................................................................................................... 107 3.7.8. Species of Special Management Concern......................................................... 109 3.7.9. Exotic/Invasive Species ...................................................................................