Practical Guidelines for Wetland Prairie Restoration in the Willamette Valley, Oregon Draft: November 14, 2013 Field-Tested Methods and Techniques August 2014 Guide Produced By Guide Authored By Jeffrey J. Krueger (Principal Landscape Architect and Guide Project Manager, LCOG) Sarah T. Bois (Director Conservation Research Program, Institute for Applied Ecology) Thomas N. Kaye (Executive Director, Institute for Applied Ecology) Diane M. Steeck (Wetland Ecologist, City of Eugene) Trevor H. Taylor (Natural Areas Restoration Supervisor, City of Eugene) Acknowledgements Special thanks to Tracie-Lynn Nadeau, Environmental Scientist, of the U.S. Environmental Protection Agency - Region 10, for her grant management and input on guide content. The authors also would like to thank Eric Wold (Natural Resources and Urban Forestry Manager, City of Eugene), Erin Gray (Ecologist, Institute for Applied Ecology), and Peg Boulay (Co- Director, University of Oregon Environmental Leadership Program) for providing input on guide content and review; to Ed Alverson for compiling the list of Vascular Plants of the Prairies and Associated Habitats of the Willamette Valley-Puget Trough-Georgia Basin Ecoregion included as Appendix A of this guide; and to David Richey (Senior GIS Analyst, LCOG) for producing the Historical Vegetation Map and data. Funding Funding for the production of this guide and associated research was provided by the U.S. Environmental Protection Agency, with matching funds provided by the City of Eugene, Institute for Applied Ecology, and the University of Oregon Environmental Leadership Program. Table of Contents Chapter 1: Background and Purpose .....................................................................................................1 1.1 Purpose and Focus of Guide ........................................................................................................... 1 1.2 Background ..................................................................................................................................... 2 Chapter 2: Wetland Prairie of the Willamette Valley .............................................................................3 2.1 Historical Extent and Condition..... .................................................................................................. 3 2.2 Wetland Prairie Ecology.... .............................................................................................................. 3 2.2.1 Native American Influences and Cultural Significance ....................................................... 5 2.2.2 Geomorphology, Topography, and Hydrology .................................................................... 6 2.2.3 Vegetation .......................................................................................................................... 7 2.2.4 Wildlife ............................................................................................................................... 9 2.3 Current Extent and Significant Wetland Prairie Sites .................................................................... 10 2.4 Issues and Challenges of Restoration and Long-Term Management..... ....................................... 11 2.4.1 Hydrologic Modification .................................................................................................... 11 2.4.2 Scale and Edge Effect ......................................................................................................... 11 2.4.3 Colonization by Non-Native Plant Species ......................................................................... 11 2.4.4 Woody Vegetation Encroachment ..................................................................................... 12 2.4.5 Species Imbalance and Loss of Diversity ........................................................................... 12 2.4.6 Thatch Build-Up ................................................................................................................. 13 2.4.7 Loss of Topographic Variation ........................................................................................... 13 2.4.8 Climate Change ................................................................................................................. 13 2.4.9 Soil Structure and Nutrient Alternations ........................................................................... 14 Chapter 3: Wetland Prairie Restoration, Enhancement, and Management Overview .......................... 15 3.1 Range of Condition Prior to Restoration and Enhancement ......................................................... 15 3.1.1 Managed/Restored High to Moderate Quality Wetland Prairies ...................................... 15 3.1.2 Low to Moderate Remnant Wetland Prairies .................................................................... 16 3.1.3 Degraded Old Field Wetland Prairies ................................................................................ 16 3.1.4 Agricultural Wetlands ........................................................................................................ 16 3.1.5 Filled Wetlands .................................................................................................................. 17 3.2 Wetland Prairie Restoration Process .............................................................................................. 18 Step 1: Site Selection ................................................................................................................. 18 Step 2: Site Analysis ................................................................................................................... 19 Step 3: Planning and Design ....................................................................................................... 20 Step 4: Site Preparation .............................................................................................................. 21 Step 5: Establishment ................................................................................................................. 22 Step 6: Long-Term Management ................................................................................................ 23 3.3 Defining Success ............................................................................................................................ 24 Chapter 4: Site Preparation (Years 1-2)................................................................................................ 25 4.1 Importance of Site Preparation ...................................................................................................... 25 4.2 Pre-Existing Site Conditions ........................................................................................................... 25 4.3 Hydrologic and Topographic Modifications .................................................................................... 26 4.3.1 Assessing and Documenting Surface Hydrology................................................................ 26 4.3.2 Removal or Conversion of Agricultural Drainage Features ................................................ 27 4.3.3 Fill Removal ....................................................................................................................... 28 4.3.4 Modifying Hydrology to Benefit Habitat Conditions ......................................................... 28 4.4 Eradicating Existing Non-Native Vegetation and Associated Seed Bank ........................................ 30 4.4.1 Range of Site Preparation Techniques ............................................................................... 30 4.4.2 Overview and Results of Site Preparation Field Experiments (2004-2007) ....................... 32 Continued Next Page 4.5 Recommended Site Preparation Approach and Timeline ............................................................. 35 4.6 Common Themes and Variations in Site Preparation .................................................................... 36 4.7 Site Preparation Approaches for Special Habitat Conditions ........................................................ 38 4.8 Knowledge Gaps Related to Site Preparation ................................................................................ 38 Chapter 5: Establishment Phase (Years 3-5) ........................................................................................ 39 5.1 Planning Plant Establishment ......................................................................................................... 39 5.1.1 Plant Species lists .............................................................................................................. 40 5.1.2 Diversity ............................................................................................................................ 40 5.1.3 Seed Zones ........................................................................................................................ 41 5.1.4 Succession Theory and Priority Effects .............................................................................. 42 5.2 Plant Material Type and Acquisition .............................................................................................. 44 5.2.1 Plant Material Type ........................................................................................................... 44 5.2.2 Plant Material Acquisition ................................................................................................. 45 5.3 Developing Seed Mixes .................................................................................................................