Albemarle County Biodiversity: A Report on its History, Current Conditions, and Threats, with Strategies for Future Protection Prepared by the Albemarle County Biodiversity Work Group October 2004 Dan Bieker - Ornithologist, Piedmont Virginia Community College Instructor Stephen Bowler, MS – Former Watershed Manager, Albemarle County; Graduate Research Assistant, Virginia Tech Tom Dierauf, Master of Forestry Ruth Douglas, Ph.D. - Invasive Plant Coordinator, Virginia Native Plant Society; Professor Emerita, Piedmont Virginia Community College Michael Erwin, Ph.D. - Research Professor, University of Virginia Department of Environmental Sciences; Wildlife Biologist, USGS Patuxent Wildlife Research Center Chris French – Former Conservation Technician, Thomas Jefferson Soil & Water Conservation District David Hannah, MS – Piedmont Environmental Council (former staff) John Hermsmeier - Director, Environmental Education Center Kenneth R. Lawless, Ph.D. - Professor Emeritus, University of Virginia Department of Materials Science & Engineering; Ornithologist, Field Botanist, Nature Photographer Tom Olivier, Ph.D. - Green Creek Paradigms, LLC G. Carleton Ray, Ph.D. - Research Professor, University of Virginia Department of Environmental Sciences John Scrivani, Ph.D. – Virginia Department of Forestry; Ivy Creek Foundation Board of Directors Charles E. Stevens - Field Botanist and Ornithologist; Virginia Botanical Associates Coordinated and Edited by Scott Clark - Senior Planner, Albemarle County Community Development Department 1 Acknowledgements The Biodiversity Work Group would like to thank Ridge Schuyler (Director, Piedmont Program) and Jennifer Allen (Conservation Ecologist) of The Nature Conservancy in Virginia, and Tom Smith, Natural Heritage Director of the Virginia Department of Conservation and Recreation (Division of Natural Heritage), for reviewing this report; David Hirschman for reviewing the sections on aquatic biodiversity; John Porter for his early involvement in the group’s work; and Bess Murray, Jim Murray, and Bart Bartholomew for their input. Cover photo credits: Hepatica: G. Carleton Ray; Hickory Horned Devil (caterpillar to the Imperial Moth): G. Carleton Ray. Red-tailed Hawk: Scott Clark. Red Fox: Scott Clark 2 PREFACE...................................................................................................................................... 5 BACKGROUND AND GUIDELINES FOR BIODIVERSITY CONSERVATION.............. 9 Fundamentals of Ecosystems...................................................................................................... 9 Ecosystems.............................................................................................................................. 9 Ecosystem Health.................................................................................................................. 10 Communities, Species, and Genes........................................................................................ 11 Ecosystem Services............................................................................................................... 13 Approaches to Protecting Biodiversity ..................................................................................... 14 Public Awareness of Biodiversity......................................................................................... 14 Protection of Biodiversity..................................................................................................... 14 Restoration ............................................................................................................................ 14 Ecosystem & Watershed Planning........................................................................................ 14 Management & Monitoring .................................................................................................. 15 Comprehensive Planning ...................................................................................................... 15 Summary: Strategic Guidelines for Biodiversity Protection .................................................... 16 HISTORIC IMPACTS AND MODERN THREATS TO THE CONSERVATION AND RESTORATION OF BIODIVERSITY IN ALBEMARLE COUNTY, VA ......................... 19 INTRODUCTION .................................................................................................................... 19 HISTORY OF LANDSCAPE AND WATERWAY ALTERATION AND EFFECTS ON BIODIVERSITY....................................................................................................................... 20 Terrestrial Communities and Landscapes............................................................................. 20 Aquatic and Wetland Communities and Ecosystems ........................................................... 22 HISTORY OF THE INTRODUCTION OF INVASIVE PLANTS AND ANIMALS, PLANT PESTS, DISEASES, AND FERAL ANIMALS....................................................................... 26 Invasive Alien Plants ............................................................................................................ 26 Invasive Alien Vertebrates and Invertebrates....................................................................... 27 Invasive Fungi, Microorganisms, and Viruses ..................................................................... 28 LOCAL THREATS TO CONSERVATION AND RESTORATION OF BIODIVERSITY .. 29 Legacy Threats from Historic Land Uses ............................................................................. 29 Suburbanization and Other Land Use Changes .................................................................... 29 Landscape Change and Threats from Fragmentation ........................................................... 31 Landscape Change and Threats to Waterways ..................................................................... 32 GLOBAL AND NATIONAL THREATS TO THE CONSERVATION AND RESTORATION OF BIODIVERSITY.................................................................................... 33 Airborne Pollutants ............................................................................................................... 33 Climate Change..................................................................................................................... 35 CONCLUSION......................................................................................................................... 37 METHODS FOR ASSESSMENT AND MONITORING....................................................... 39 Biodiversity Assessment Methods............................................................................................ 39 Expert Systems...................................................................................................................... 39 Gap Analysis......................................................................................................................... 40 Community Composition and Species Richness Assessment .......................................... 41 Natural Heritage Approach................................................................................................... 41 Physical Proxies for Biodiversity Measures ......................................................................... 41 Taxon-specific Approaches .................................................................................................. 42 3 Ecological Monitoring .............................................................................................................. 42 Selecting a Classification System for Terrestrial Communities ............................................... 44 Assessing the Current State of Ecosystems .............................................................................. 50 CURRENT STATE OF BIODIVERSITY IN ALBEMARLE COUNTY............................. 52 Community and Ecosystem types............................................................................................. 52 Terrestrial Habitats and Plant Communities of Albemarle County...................................... 52 Aquatic Ecosystems and Habitats of Albemarle County...................................................... 53 Stream Ecosystems ........................................................................................................... 53 Wetlands ........................................................................................................................... 55 Riparian Areas / Floodplains ............................................................................................ 56 Important Sites.......................................................................................................................... 57 Species ...................................................................................................................................... 57 Vertebrates ............................................................................................................................ 57 Trends ............................................................................................................................... 58 Policy and Management Needs......................................................................................... 58 Mammals........................................................................................................................... 59 Amphibians......................................................................................................................