HABITAT MANAGEMENT PLAN Green Bay and Gravel Island National Wildlife Refuges October 2017 Habitat Management Plans provide long-term guidance for management decisions; set forth goals, objectives, and strategies needed to accomplish refuge purposes; and, identify the Fish and Wildlife Service’s best estimate of future needs. These plans detail program planning levels that are sometimes substantially above current budget allocations and as such, are primarily for Service strategic planning and program prioritization purposes. The plans do not constitute a commitment for staffing increases, operational and maintenance increases, or funding for future land acquisition. The National Wildlife Refuge System, managed by the U.S. Fish and Wildlife Service, is the world's premier system of public lands and waters set aside to conserve America's fish, wildlife, and plants. Since the designation of the first wildlife refuge in 1903, the System has grown to encompass more than 150 million acres, 556 national wildlife refuges and other units of the Refuge System, plus 38 wetland management districts. This page intentionally left blank. Habitat Management Plan for Green Bay and Gravel Island National Wildlife Refuges EXECUTIVE SUMMARY This Habitat Management Plan (HMP) provides vision and specific guidance on enhancing and managing habitat for the resources of concern (ROC) at the refuge. The contributions of the refuge to ecosystem- and landscape-scale wildlife and biodiversity conservation, specifically migratory waterfowl, are incorporated into this HMP. The HMP is intended to provide habitat management direction for the next 15 years. The HMP is also needed to ensure that the refuge continues to conserve habitat for migratory birds in the context of climate change, which affects all units of the National Wildlife Refuge System. This HMP is a step-down plan, tiered from the Gravel Island, Green Bay, Harbor Island, Huron, and Michigan Islands National Wildlife Refuge Comprehensive Conservation Plan (CCP) (USFWS 2012). The CCP process was a multi-year, collaborative planning exercise resulting in the establishment of refuge-specific goals, objectives, and strategies, and this HMP further refines these goals and prescribes specific management actions for their implementation. The HMP builds on and amends the original objectives from the CCP to develop specific goals and strategies related to ROC. Future Inventory and Monitoring Plans and Annual Habitat Work Plans will tier from the HMP and hone in on these goals and strategies. Green Bay and Gravel Island National Wildlife Refuges (NWR) are managed by the U.S. Fish and Wildlife Service (Service) as part of the National Wildlife Refuge System (NWRS). The island refuges are managed by staff based at Horicon NWR in Mayville, WI. The five islands that make up the Green Bay NWR are located off the tip of Door County peninsula in Lake Michigan between mainland Wisconsin and Michigan. Three islands (Hog, Plum, and Pilot) lie between the tip of the Door Peninsula and Washington Island in Wisconsin waters, while 2015 additions (St. Martin Island and Rocky Island) lie further northeast and within Michigan’s border. Spider Island and Gravel Island comprise Gravel Islands NWR. These islands are also located in Lake Michigan, approximately one mile to the east of the Door Peninsula. In 1970, Gravel, Spider, and Hog Island were designated as Wilderness Areas. The Green Bay and Gravel Island NWR ROC were identified by reviewing the species known to occur within the refuge, as well as those identified in local and regional conservation plans, and analyzing their relation to the biological integrity, diversity, and environmental health (BIDEH) of the habitats present on the refuge. The comprehensive ROC list was then narrowed down by selecting species most likely to represent a suite of habitat needs for other species (i.e., focal or surrogate species). Based on this analysis, the refuge identified 7 priority ROC, including 3 birds, 1 plant, and 3 natural communities. More information on these ROC and their selection is detailed in Chapter 3. As part of the ROC identification, habitats were also prioritized for future management. Priorities were based on each habitat’s ability to be managed effectively to support ROCs. Based on this review, the refuge identified the following priority habitats (ordered from greater to lesser importance): early successional habitat/colonial nesting areas, northern mesic forest, Great Lakes rock shore and alvar. Lastly, the HMP establishes a list of appropriate management actions pertinent to achieving determined priority habitat and ROC goals. Executive Summary i October 2017 Habitat Management Plan for Green Bay and Gravel Island National Wildlife Refuges This HMP defines the refuge’s important role in providing breeding habitat for colonial nesting birds, as well as migratory stopover habitat. Similarly, the refuges provide a unique landscape context and protection for several rare natural communities and endangered plants. Its location along the Niagara Escarpment and Lake Michigan makes it a major stopover and breeding focal area for many species. The selection of priorities and management actions within this plan reflect the refuge’s contribution to these resources. Executive Summary ii October 2017 Habitat Management Plan for Green Bay and Gravel Island National Wildlife Refuges This page intentionally left blank. Executive Summary iii October 2017 Habitat Management Plan for Green Bay and Gravel Island National Wildlife Refuges TABLE OF CONTENTS EXECUTIVE SUMMARY ............................................................................................................................... I 1. INTRODUCTION .............................................................................................................................. 1-1 Purpose of Green Bay and Gravel Island National Wildlife Refuges ........................... 1-1 Refuge Overview ............................................................................................................... 1-1 Scope of Habitat Management Plan ................................................................................ 1-5 Mission Mandates ............................................................................................................. 1-5 Habitat Management Planning Relationship to Other Plans ........................................ 1-6 2. BACKGROUND ............................................................................................................................... 2-1 Refuge Background .......................................................................................................... 2-1 Refuge Islands Overview and Habitats ........................................................................... 2-2 Changes from Historic Condition and Current Issues .................................................. 2-9 Land Classification and Plant Communities ................................................................ 2-17 3. RESOURCES OF CONCERN ......................................................................................................... 3-1 Introduction ....................................................................................................................... 3-1 Identification of Refuge Resources of Concern ............................................................. 3-1 Biological Integrity, Diversity, and Environmental Health ............................................ 3-4 Priority District Resources of Concern ........................................................................... 3-5 Habitat Types and Associated Priority Species ........................................................... 3-14 Conflicting Habitat Management ................................................................................... 3-17 Adaptive Management .................................................................................................... 3-18 4. HABITAT GOAL, OBJECTIVES, AND MANAGEMENT STRATEGIES ...................................... 4-23 Refining CCP Objectives within the HMP ..................................................................... 4-23 HMP Goal, Objectives, and Management Strategies ................................................... 4-24 Prioritization of Management Units ............................................................................... 4-26 HMP Objective 1: Maintain and Evaluate Wilderness Characteristics ...................... 4-28 HMP Objective 2: Early Successional Habitat/Colonial Nesting Areas ................................................................................................................................ 4-30 HMP Objective 3: Northern Mesic Forest ..................................................................... 4-33 HMP Objective 4: Great Lakes Alkaline Rock Shore and Alvar .................................. 4-37 5. REFERENCES ................................................................................................................................. 5-1 Table of Contents i October 2017 Habitat Management Plan for Green Bay and Gravel Island National Wildlife Refuges LIST OF FIGURES Figure 1-1. Map of St. Martin Island depicting areas purchased and donated by the Nature Conservancy, as well as areas still owned by the Little Traverse Bay Band of Odawa Indians (TNC 2014). ...................................................... 1-2 Figure 1-2. Locations of Green Bay and Gravel Islands Units. ..........................................................