National Park Service U.S. Department of the Interior Natural Resource Program Center Assessment of natural resource conditions in and adjacent to Acadia National Park, Maine Natural Resource Report NPS/NRPC/WRD/NRR—2008/069 ON THE COVER Clockwise, from top left: Maple Spring Bridge, view from Sargent Mountain, ferns near Sieur de Monts Spring, water striders on Hadlock Brook, Cañon Brook near Murray Young trail, sunrise from Schoodic Point in winter, Jesup Path in autumn, Cañon Brook in winter. Center: trail signpost near Cadillac Mountain. All photos: Sarah Nelson or Ken Johnson. Assessment of natural resource conditions in and adjacent to Acadia National Park Natural Resource Report NPS/NRPC/WRD/NRR—2008/069 Peter D. Vaux (1) Sarah J. Nelson (1) Nishi Rajakaruna (2) Glen Mittelhauser (3) Kathleen Bell (4) Blaine Kopp (5) John Peckenham (1) Gordon Longsworth (2) (1) Senator George J. Mitchell Center for Environmental and Watershed Research University of Maine, Orono, Maine 04469 (2) College of the Atlantic, Bar Harbor, Maine 04609 (3) Maine Natural History Observatory, Gouldsboro, Maine 04607 (4) Dept. of Resource Economics and Policy, University of Maine, Orono, Maine 04469 (5) 48 Winthrop St., Hallowell, ME 04347 This report was prepared under Task Order J4506060620 of the North Atlantic Coast Cooperative Ecosystem Studies Unit (Cooperative Agreement between the National Park Service and University of Maine, 1443CA4520-99-007, amendment #2) November 2008 U.S. Department of the Interior National Park Service Natural Resource Program Center Fort Collins, Colorado The Natural Resource Publication series addresses natural resource topics that are of interest and applicability to a broad readership in the National Park Service and to others in the management of natural resources, including the scientific community, the public, and the NPS conservation and environmental constituencies. Manuscripts are peer-reviewed to ensure that the information is scientifically credible, technically accurate, appropriately written for the intended audience, and is designed and published in a professional manner. Natural Resource Reports are the designated medium for disseminating 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. Examples of the diverse array of reports published in this series include vital signs monitoring plans; monitoring protocols; "how to" resource management papers; proceedings of resource management workshops or conferences; annual reports of resource programs or divisions of the Natural Resource Program Center; resource action plans; fact sheets; and regularly-published newsletters. Views, statements, findings, conclusions, recommendations and data in this report are solely those of the author(s) and do not necessarily reflect views and policies of the U.S. Department of the Interior, NPS. Mention of trade names or commercial products does not constitute endorsement or recommendation for use by the National Park Service. Printed copies of reports in these series may be produced in a limited quantity and they are only available as long as the supply lasts. This report is also available from the Water Resources Division of the National Park Service website (http://www.nature.nps.gov/water/wrdpub.cfm) or http://www.nature.nps.gov/publications/NRPM/ on the internet, or by sending a request to the address on the back cover. Please cite this publication as: Vaux, P. D., S. J. Nelson, N. Rajakaruna, G. Mittelhauser, K. Bell, B. Kopp, J. Peckenham, and G. Longsworth. 2008. Assessment of natural resource conditions in and adjacent to Acadia National Park, Maine. Natural Resource Report NPS/NRPC/WRD/NRR—2008/069. National Park Service, Fort Collins, Colorado. NPS D-344, November 2008 ii Contents Figures.......................................................................................................................................... viii Tables ............................................................................................................................................ xii Acronyms and Abbreviations ........................................................................................................ xiii Executive Summary...................................................................................................................... xv Acknowledgements.....................................................................................................................xviii Introduction ..................................................................................................................................... 1 Park Description.............................................................................................................................. 3 Size and Location of Park Lands and Conservation Easements ..................................................... 3 Location and Extent of the Upland, Freshwater, Wetland and Marine/Coastal Systems ............... 6 Legislative Background and Management Objectives ................................................................... 9 Human Utilization of Park Resources ............................................................................................. 9 Terrestrial, Freshwater and Coastal/Marine Resources ................................................................ 17 Terrestrial Systems........................................................................................................................ 17 Physico-Chemical Environment of Terrestrial Systems ................................................... 17 Biological Resources of Terrestrial Systems .................................................................... 19 Freshwater Systems (Lakes, Streams, Riparian Systems, Wetlands and Groundwater) .............. 33 Physico-Chemical Environment of Freshwater Systems .................................................. 33 Biological Resources of Freshwater Systems ................................................................... 47 Marine / Coastal Systems .............................................................................................................. 56 Physico-Chemical Environment of Marine / Coastal Systems ......................................... 56 Biological Resources of Marine / Coastal Systems .......................................................... 59 Assessment of Threats .................................................................................................................. 64 iii Introduction ................................................................................................................................... 64 Ultraviolet Radiation ..................................................................................................................... 65 Visibility Impairments .................................................................................................................. 67 Ozone ............................................................................................................................................ 67 Atmospheric Ozone Levels ............................................................................................... 67 Ozone Impacts on Terrestrial Vegetation ......................................................................... 70 Atmospheric Deposition (Acidity and Related Chemistry) .......................................................... 71 Atmosphere: Deposition Chemistry .................................................................................. 72 Impacts of Atmospheric Acidity on Terrestrial Systems .................................................. 76 Impacts of Atmospheric Nitrogen on Terrestrial Vegetation ........................................... 76 Impacts of Atmospheric Deposition on Freshwater Systems ........................................... 79 Atmospheric Nitrogen Deposition to Coastal and Marine Systems ................................. 83 Mercury ......................................................................................................................................... 84 Atmospheric Sources ........................................................................................................ 84 Mercury in Terrestrial Systems ......................................................................................... 86 Mercury in Freshwater Systems (Abiotic Components) ................................................... 87 Mercury in Terrestrial and Freshwater Biota .................................................................... 89 Mercury in Marine Systems .............................................................................................. 92 Nutrient Enrichment ...................................................................................................................... 95 Nutrient Enrichment: Terrestrial Systems ........................................................................ 95 Nutrient Enrichment: Lakes and Streams ......................................................................... 95 Nutrient Enrichment: Wetlands and Estuaries .................................................................. 98 Nutrient Enrichment: Other Coastal and Marine Areas .................................................. 103 Microbial Contamination ...........................................................................................................