Currituck National Wildlife Refuge Comprehensive Conservation Plan

              Currituck National Wildlife Refuge
Comprehensive Conservation Plan
U.S. Department of the Interior
Fish and Wildlife Service
Southeast Region
November 2008
COMPREHENSIVE CONSERVATION PLAN
CURRITUCK NATIONAL WILDLIFE REFUGE
Currituck County, North Carolina
U.S. Department of the Interior
Fish and Wildlife Service
Southeast Region
Atlanta, Georgia
November 2008
Table of Contents i
TABLE OF CONTENTS
EXECUTIVE SUMMARY ....................................................................................................................... 1
COMPREHENSIVE CONSERVATION PLAN
I. BACKGROUND ................................................................................................................................. 1
Introduction .................................................................................................................................. 1
Purpose and Need for the Plan .................................................................................................... 2
U.S. Fish and Wildlife Service ...................................................................................................... 2
National Wildlife Refuge System .................................................................................................. 3
Refuges of the Ecosystem ............................................................................................................ 4
Legal Policy Context ..................................................................................................................... 4
National Conservation Plans and Initiatives ................................................................................. 4
Relationship to State Partners ...................................................................................................... 5
II. REFUGE OVERVIEW ........................................................................................................................ 7
Introduction .................................................................................................................................. 7
Location and size ................................................................................................................ 7
Establishment ...................................................................................................................... 7
Refuge History and Purposes ....................................................................................................... 7
Acquisition History ............................................................................................................... 7
Purposes ............................................................................................................................. 7
Special Designations .................................................................................................................. 10
Ecosystem Context ..................................................................................................................... 10
Regional Conservation Plans and Initiatives .............................................................................. 10
Ecological Threats and Problems ............................................................................................... 12
Habitat Loss and Fragmentation ....................................................................................... 12
Alterations to Hydrology .................................................................................................... 13
Siltation of Aquatic Ecosystems ........................................................................................ 14
Proliferation of Invasive Aquatic Plants ............................................................................. 14
Conservation Priorities ...................................................................................................... 14
Physical Environment ................................................................................................................. 16
Climate .............................................................................................................................. 16
Geology ............................................................................................................................. 17
Soils ................................................................................................................................. 21
Hydrology .......................................................................................................................... 22
Water Quality .................................................................................................................... 23
Air Quality .......................................................................................................................... 26
Visual Resources/Aesthetics ............................................................................................. 26
Biological Environment ............................................................................................................... 27
Habitat ............................................................................................................................... 27
Wildlife ............................................................................................................................... 34
Exotic Organisms .............................................................................................................. 40
Socioeconomic Conditions ................................................................................................ 41
History of the Area ............................................................................................................ 44
Land Use ........................................................................................................................... 47
Demographics ................................................................................................................... 52
Employment ...................................................................................................................... 54
ii Currituck National Wildlife Refuge
Forestry ............................................................................................................................. 54
Outdoor Recreation .......................................................................................................... 55
Outdoor Recreation Economics ........................................................................................ 56
Tourism ............................................................................................................................. 57
Transportation ................................................................................................................... 57
Cultural Environment ........................................................................................................ 57
Refuge Administration and Management ................................................................................... 58
Land Protection and Management .................................................................................... 58
Visitor Services ................................................................................................................. 58
Personnel, Operations, and Maintenance ........................................................................ 59
III. PLAN DEVELOPMENT .................................................................................................................. 63
Public Involvement and the Planning Process ........................................................................... 63
Plan Review and Revision .......................................................................................................... 64
Wilderness Review ..................................................................................................................... 64
Summary of Issues, Concerns, and Opportunities ..................................................................... 64
Global Warming and Sea Level Rise ................................................................................ 65
Fish and Wildlife Populations ............................................................................................ 65
Habitats ............................................................................................................................. 67
Public Use ......................................................................................................................... 67
Resource Protection ......................................................................................................... 68
General Administration ..................................................................................................... 69
IV. MANAGEMENT DIRECTION ......................................................................................................... 71
Introduction ............................................................................................................................... 71
Vision ........................................................................................................................................ 72
Vision ........................................................................................................................................ 73
Goals, Objectives, and Strategies .............................................................................................. 73
Goals ............................................................................................................................... 73
Objectives and Strategies ................................................................................................. 73
V. PLAN IMPLEMENTATION .............................................................................................................. 95
Proposed Projects ...................................................................................................................... 95
Refuge Administration ................................................................................................................ 99
Funding and Personnel .............................................................................................................. 99
Volunteers ............................................................................................................................... 101
Partnership Opportunities ........................................................................................................ 101
Step-down Management Plans ................................................................................................ 101
Monitoring and Adaptive Management ..................................................................................... 103
APPENDICES
APPENDIX I. GLOSSARY ................................................................................................................ 105
APPENDIX II. REFERENCES AND LITERATURE CITED .............................................................. 111
APPENDIX III. RELEVANT LEGAL MANDATES ............................................................................. 119
Table of Contents iii
APPENDIX IV. PUBLIC INVOLVEMENT .......................................................................................... 127
Public Scoping .......................................................................................................................... 127
Public Comments on Draft Plan and Service Responses ........................................................ 127
APPENDIX V. DECISIONS AND APPROVALS ............................................................................... 135
Intra-Service Section 7 Biological Evaluation ........................................................................... 135
Compatibility Determinations .................................................................................................... 139
APPENDIX VI. REFUGE BIOTA ....................................................................................................... 153
APPENDIX VII. PRIORITY BIRD SPECIES AND THEIR HABITATS ............................................... 175
APPENDIX VIII. BUDGET REQUESTS ............................................................................................ 177
APPENDIX IX. BIOLOGICAL REVIEW ............................................................................................. 191
APPENDIX X. CONSULTATION AND COORDINATION ................................................................. 205
APPENDIX XI. FINDING OF NO SIGNIFICANT IMPACT ................................................................ 207
iv Currituck National Wildlife Refuge
LIST OF FIGURES
Figure 1. Location of Currituck National Wildlife Refuge, Currituck County, North Carolina. ............... 8
Figure 2. Currituck National Wildlife Refuge in the South Atlantic Coastal Plain physiographic area. ......... 11
Figure 3. Soils of Currituck National Wildlife Refuge. ......................................................................... 24
Figure 4. National Wetland Inventory map of Currituck National Wildlife Refuge. .............................. 28
Figure 5. Profile of vegetative communities of coastal barrier islands. ............................................... 27
Figure 6. Approved acquisition boundary, Currituck National Wildlife Refuge. .................................. 60
Figure 7. Current visitor facilities at Currituck National Wildlife Refuge.............................................. 62
Figure 8. Proposed visitor facilities at Currituck National Wildlife Refuge under Alternative 2. .......... 72
LIST OF TABLES
Table 1. Acquisition history of Currituck National Wildlife Refuge. ....................................................... 9
Table 2. The Nature Conservancy ranking of vegetative communities of Currituck
National Wildlife Refuge. ......................................................................................................... 9
Table 3. Federally listed threatened and endangered animal species in the
Coastal Plain of North Carolina. ............................................................................................ 13
Table 4. Characteristics of soils of Currituck National Wildlife Refuge. .............................................. 22
Table 5. Classifications of water bodies and streams surrounding Currituck
National Wildlife Refuge. ....................................................................................................... 25
Table 6. Vegetative composition of the Swan Island Moist Soil Unit. ................................................. 33
Table 7. Currituck National Wildlife Refuge waterfowl survey results, 2002-2003. ............................ 36
Table 8. Species of management concern at Currituck National Wildlife Refuge. ............................. 42
Table 9. Currituck County agricultural statistics, 2002. ...................................................................... 48
Table 10. Commodity production in Currituck County, 1997 and 2002. ............................................. 49
Table 11. Dare County agricultural statistics, 2002. ........................................................................... 50
Table 12. Commodity production in Dare County, 1997 and 2002. .................................................... 50
Table 13. Virginia Beach agricultural statistics, 2002. ........................................................................ 50
Table 14. Commodity production in Virginia Beach, 1997 and 2002. ................................................. 51
Table 15. Economic and population data for northeastern North Carolina counties. ......................... 52
Table 16. Staff of Mackay Island and Currituck National Wildlife Refuges, 2005. .............................. 59
Table 17. Projects supporting Wildlife Strategies. .............................................................................. 95
Table 18. Projects supporting Habitat Strategies. .............................................................................. 96
Table 19. Projects supporting Public Use Strategies. ........................................................................ 97
Table 20. Projects supporting Resource Protection Strategies. ......................................................... 98
Table 21. Projects supporting Refuge Administration Strategies. ...................................................... 99
Table 22. Proposed staffing plan for Mackay Island and Currituck National Wildlife Refuges. ........ 100
Table 23. Currituck National Wildlife Refuge step-down management plans. .................................. 103
Executive Summary
Executive Summary
The U.S. Fish and Wildlife Service prepared this Comprehensive Conservation Plan to guide the
management of Currituck National Wildlife Refuge in Currituck County, North Carolina. The plan
outlines programs and corresponding resource needs for the next 15 years, as mandated by the
National Wildlife Refuge Improvement Act of 1997.
Before the Service began planning, it conducted a biological review of the refuge’s wildlife and habitat
management program and conducted public scoping meetings to solicit public opinion of the issues
the plan should address. The biological review team was composed of biologists from federal and
state agencies and nongovernmental organizations that have an interest in the refuge. The refuge
staff held four public scoping meetings and a round of public meetings to solicit public reaction to the
proposed alternatives during the 30 day public review and comment period of the draft
Comprehensive Conservation Plan and the Environmental Assessment.
The Service developed and analyzed three alternatives. Alternative 1 was a proposal to maintain the
status quo. The refuge currently manages its impoundments by managing water levels and
vegetation to create 50% good vegetation for migrating waterfowl, but does not manage for mudflats
for shorebirds. It also manages marshes with prescribed fire. The staff surveys waterfowl on a
routine basis. The refuge allows the six priority public use activities: hunting, fishing, wildlife
observation, wildlife photography, and environmental education and interpretation. The staff
conducts environmental education and interpretation on an as-requested basis only. The refuge
currently has seven staff members, all of whom are stationed at Mackay Island National Wildlife
Refuge. They spend 2.85 full-time equivalent (FTE) staff years at Currituck National Wildlife Refuge
and 4.15 FTE staff years on Mackay Island.
Alternative 2 proposed moderate program increases. Under this alternative, the refuge would
develop a habitat management plan and manage all habitats on the refuge. The refuge would
manage its impoundments by managing water levels and vegetation to create 60% good vegetation
for migrating waterfowl and 20% mudflats in the spring for shorebirds when feasible. The staff would
monitor vegetation in the marshes before and after prescribed burns and inventory vegetation in the
maritime swamp forest. They would survey a wide range of wildlife on the refuge. The refuge would
continue to allow the six priority public use activities, but would have the capacity to increase the
number of opportunities. The staff would conduct regularly scheduled environmental education and
interpretation programs. The Service would partner with the North Carolina Wildlife Resources
Commission to use the environmental education center being built by the Commission in Corolla.
There would be fifteen staff members, four of whom would be stationed at Currituck and eleven of
whom would be stationed at Mackay Island. They would spend 7.2 FTE staff years at Currituck and
7.8 FTE staff years at Mackay Island. The staff would include a biologist, public use specialist, refuge
operations specialist, and law enforcement officer.
Alternative 3 proposed substantial program increases. Under this alternative, the refuge would
develop a habitat management plan and manage all habitats on the refuge. The refuge would
manage its impoundments by managing water levels and vegetation to create 70% good vegetation
for migrating waterfowl and 20% mudflats in the spring and10% in the fall for shorebirds. The staff
would survey invertebrates in the mudflats to determine the effect of management. The staff would
monitor vegetation in the marshes before and after prescribed burns, adapt the burn plan to the
monitoring results, and inventory vegetation in the maritime swamp forest. They would survey all
wildlife on the refuge. The refuge would increase further the number of public use opportunities. The
Currituck National Wildlife Refuge
Service would use the environmental education center being built by the North Carolina Wildlife
Resources Commission. There would be twenty-four staff members, seven of whom would be
stationed at Currituck and seventeen of whom would be stationed at Mackay Island. They would
spend 12.75 FTE staff years at Currituck and 11.25 FTE staff years at Mackay Island. The staff
would include separate law enforcement officers and public use specialists for each refuge.
The staff selected Alternative 2 as its preferred alternative, which is reflected in this final
Comprehensive Conservation Plan. It advances the refuge program considerably, and is more
realistic than Alternative 3 in terms of expected staffing levels to conduct the proposed program.
Comprehensive Conservation Plan 1
COMPREHENSIVE CONSERVATION PLAN
I. Background
INTRODUCTION
The U.S. Fish and Wildlife Service (Service) has developed this Comprehensive Conservation
Plan to provide a foundation for the management and use of Currituck National Wildlife Refuge
in Currituck County, North Carolina. The plan will serve as a guide for the refuge’s
management programs and actions over the next 15 years.
The Service developed this plan in compliance with the National Wildlife Refuge System
Improvement Act of 1997 and Part 602 (National Wildlife Refuge System Planning) of the Fish
and Wildlife Service Manual. The actions described within this plan also meet the requirements
of the National Environmental Policy Act of 1969. The Service achieved compliance with this
Act through the involvement of the public and the incorporation of an Environmental
Assessment in this document, which describes the alternatives considered and an analysis of
the environmental consequences of the alternatives. When fully implemented, this plan will
strive to achieve the vision and purposes of Currituck National Wildlife Refuge.
The plan’s overriding consideration is to carry out the purposes for which the refuge was
established. Fish and wildlife are the first priority in refuge management, and the Service
allows and encourages public uses (wildlife-dependent recreation) as long as it is compatible
with, or does not detract from, the refuge’s mission and purposes.
The plan was prepared by a planning team that consisted of representatives from various
Service programs, including the divisions of Refuges, Fisheries, Ecological Services, Realty,
and Migratory Birds. In developing this plan, the planning team and refuge staff incorporated
the input of local citizens and the general public through a series of stakeholder and public
scoping meetings. A description of this public involvement and the planning process itself are
provided in Chapter III, Plan Development.
This plan represents the Service’s preferred alternative and is being put forward after
considering two other alternatives, as described in the Environmental Assessment which
accompanied the Draft CCP and as summarized in the Executive Summary. After reviewing a
wide range of public comments and management needs, the planning team developed these
alternatives in an attempt to determine how to best meet the goals and objectives of Currituck
National Wildlife Refuge. The preferred alternative is the Service’s recommended course of
action for the future management of the refuge, and forms the basis for this comprehensive
conservation plan.
2 Currituck National Wildlife Refuge
PURPOSE AND NEED FOR THE PLAN
The purpose of this comprehensive conservation plan is to identify the role that Currituck National
Wildlife Refuge will play in support of the mission of the National Wildlife Refuge System, and to
provide long-term guidance to the refuge’s management programs and activities for the next 15
years. The plan is needed to
􀁹􇤠 provide a clear statement of direction for the future management of the refuge;
􀁹􇤠 provide refuge neighbors, visitors, and government officials with an understanding of the U.S.
Fish and Wildlife Service’s management actions on and around the refuge;
􀁹􇤠 ensure that the Service’s management actions, including land protection and recreational and
educational programs, are consistent with the mandates of the National Wildlife Refuge System
Improvement Act of 1997;
􀁹􇤠 ensure that the management of the refuge is consistent with federal, state, and county plans;
and
􀁹􇤠 provide a basis for the development of budget requests for the refuge’s operational,
maintenance, and capital improvement needs.
Perhaps the greatest need of the Service is to communicate with the public and include public
participation in its efforts to carry out the mission of the National Wildlife Refuge System. Many
agencies, organizations, institutions, businesses, and private citizens have developed relationships
with the Service to advance the goals of the Refuge System. This Comprehensive Conservation Plan
supports the Partners in Flight Initiative; South Atlantic Coastal Plain Migratory Bird Conservation
Plan; North American Waterfowl Management Plan; Western Hemisphere Shorebird Reserve
Network; and National Wetlands Priority Conservation Plan.
U.S. FISH AND WILDLIFE SERVICE
The U.S. Fish and Wildlife Service is the primary federal agency responsible for the conservation,
protection, and enhancement of the Nation’s fish and wildlife populations and their habitats. Although
the Service shares some conservation responsibilities with other federal, state, tribal, local, and
private entities, it has specific trustee obligations for migratory birds, threatened and endangered
species, anadromous fish, and certain marine mammals. In addition, the Service administers a
national network of lands and waters for the management and protection of these resources.
As part of its mission, the Service manages more than 540 national wildlife refuges covering a total of
more than 93 million acres. These areas comprise the National Wildlife Refuge System, the world’s
largest collection of lands and waters specifically managed for fish and wildlife. The majority of these
lands, 77 million acres, lie in Alaska. The remaining 16 million acres are spread across the other 49
states and several island territories.
Comprehensive Conservation Plan 3
NATIONAL WILDLIFE REFUGE SYSTEM
The mission of the System, as defined by the National Wildlife Refuge System Improvement Act of
1997, is:
... to administer a national network of lands and waters for the conservation, management,
and where appropriate, restoration of the fish, wildlife and plant resources and their habitats
within the United States for the benefit of present and future generations of Americans.
The National Wildlife Refuge System Improvement Act of 1997 established, for the first time, a clear
mission of wildlife conservation for the national wildlife refuge system. The Act states that each
refuge shall be managed to
􀁹􇤠 fulfill the mission of the Refuge System;
􀁹􇤠 fulfill the individual purposes of each refuge;
􀁹􇤠 consider the needs of fish and wildlife first;
􀁹􇤠 fulfill the requirement of developing a comprehensive conservation plan for each unit of the
Refuge System, and fully involve the public in the preparation of these plans;
􀁹􇤠 maintain the biological integrity, diversity, and environmental health of the Refuge System;
􀁹􇤠 recognize that wildlife-dependent recreational activities including hunting, fishing, wildlife
observation, wildlife photography, and environmental education and interpretation are legitimate
and priority public uses; and
􀁹􇤠 retain the authority of refuge managers to determine compatible public uses.
Following passage of the Act in 1997, the Service immediately began efforts to carry out the direction
of the new legislation, including the preparation of comprehensive conservation plans for all refuges.
The development of these plans is now ongoing nationally. Consistent with the Act, The Service is
preparing all refuge comprehensive conservation plans in conjunction with public involvement, and
each refuge is completing its own plan within a 15-year schedule.
Approximately 37.5 million people visited the country’s national wildlife refuges in 1998, mostly to
observe wildlife in their natural habitats. As this visitation continues to grow, substantial economic
benefits are being generated to the local communities that surround the refuges. Economists have
reported that national wildlife refuge visitors contribute more than $400 million annually to the local
economies. In addition, the National Survey of Fishing, Hunting, and Wildlife-associated Recreation
reports that nearly 40 percent of the country’s adults spent $108 billion on wildlife-related recreational
pursuits in 2001 (U.S. Fish and Wildlife Service 2001).
Volunteerism continues to be a major contributor to the successes of the Refuge System. In 1998,
volunteers contributed more than 1.5 million person-hours on the refuges nationwide, a service
valued at more than $20.6 million.
4 Currituck National Wildlife Refuge
The wildlife and habitat vision for the national wildlife refuges stresses the following principles:
􀁹􇤠 Wildlife comes first.
􀁹􇤠 Ecosystems, biodiversity, and wilderness are vital concepts in refuge management.
􀁹􇤠 Refuges must be healthy.
􀁹􇤠 Growth of refuges must be strategic.
􀁹􇤠 The National Wildlife Refuge System serves as a model for habitat management with broad
participation from others.
REFUGES OF THE ECOSYSTEM
Currituck National Wildlife Refuge is one of the ten national wildlife refuges in eastern North Carolina.
Those ten national wildlife refuges—Alligator River, Cedar Island, Currituck, Great Dismal Swamp,
Mackay Island, Mattamuskeet, Pea Island, Pocosin Lakes, Swanquarter, Roanoke River, and the
Back Bay National Wildlife Refuge in Virginia—are all located in the watersheds of the Roanoke, Tar,
Neuse, and Cape Fear rivers, which has been classified as Ecosystem Unit #34 by the U.S. Fish and
Wildlife Service.
LEGAL POLICY CONTEXT
A variety of international treaties, federal laws, federal regulations, department and Service policies,
and presidential executive orders guide the administration of Currituck National Wildlife Refuge. The
documents and acts listed in Appendix III contain management options under the refuge’s
establishing authority; the National Wildlife Refuge Administration Act of 1966; and the National
Wildlife Refuge System Improvement Act of 1997, the legal and policy guidance for the operation of
national wildlife refuges.
NATIONAL CONSERVATION PLANS AND INITIATIVES
Along with the Service’s legal mandates and initiatives, other planning activities directly influence the
development of the comprehensive conservation plan. Various groups and agencies develop and
coordinate planning initiatives involving federal, state, and local agencies; local communities;
nongovernmental organizations; and private individuals to help restore habitats for fish and wildlife on
and off public lands.
The Service is initiating cooperative partnerships in an effort to reduce the declining trend in biological
diversity. Biological planning for species groups targeted in this plan reflects the North American
Waterfowl Management Plan. The North American Waterfowl Management Plan of 1986 brings
together international teams of biologists from private and government organizations from Canada
and the United States. The partnerships, called joint ventures, are working to restore waterfowl and
other migratory bird populations to the levels of the early 1970s by protecting about 6 million acres of
priority wetland habitats from the Gulf of Mexico to the Canadian Arctic.
Comprehensive Conservation Plan 5
The United States Shorebird Conservation Plan and the Waterbirds for the Americas outline
approaches to conserving those species groups. Restoration of migratory songbird populations is a
high priority of the Partners in Flight Plan. It also provides strategies for conserving and managing
wintering, breeding, and migration habitat for midcontinental wood duck and colonial bird populations.
The Partners in Flight Plan emphasizes landbird species as a priority for conservation. Habitat loss,
population trends, and the vulnerability of species and habitats to threats are all factors used in the
priority ranking of species. Further, biologists have identified focal species for each habitat type from
which they will determine population and habitat objectives and conservation actions. This list of
focal species, objectives, and conservation actions will aid migratory bird management on the refuge.
The Farm Bill programs administered by the U.S. Department of Agriculture provide cost-share
funding and technical assistance to private landowners to install and manage conservation practices
on working farms and forests and to restore cropland to natural habitats. The programs provide
opportunities for landowners in the vicinity of national wildlife refuges to better manage their land as
wildlife habitat or protect it with easements.
RELATIONSHIP TO STATE PARTNERS
A provision of the National Wildlife Refuge System Improvement Act of 1997, and subsequent agency
policy, is that the Service shall ensure timely and effective cooperation and collaboration with other
federal agencies and state fish and wildlife agencies during the course of acquiring and managing
refuges. This cooperation is essential in providing the foundation for the protection and management
of fish and wildlife throughout the United States.
The North Carolina Wildlife Resources Commission is a state-partnering agency with the Service
charged with enforcement responsibilities for migratory birds and endangered species, as well as
managing the state’s natural resources. It also manages approximately 1.8 million acres of game
lands in North Carolina.
The Commission coordinates the state’s wildlife conservation program and provides public recreation
opportunities, including an extensive hunting and fishing program, on several game lands and from
several boat ramps located near Currituck National Wildlife Refuge. The Commission’s participation
and contribution throughout this comprehensive conservation planning process has been valuable. It
is continuing its work with the Service to provide ongoing opportunities for an open dialogue with the
public to improve the condition of fish and wildlife populations in North Carolina. Not only has the
Commission participated in biological reviews, stakeholder meetings, and field reviews as part of the
comprehensive planning process, it also is an active partner in the planning and coordination of
annual hunting seasons and various wildlife and habitat surveys. Currituck National Wildlife Refuge
provides hunting opportunities for waterfowl in cooperation with the Commission. A key part of the
comprehensive planning process is the integration of common mission objectives between the
Service and the Commission, where appropriate.
6 Currituck National Wildlife Refuge
Comprehensive Conservation Plan 7
II. Refuge Overview
INTRODUCTION
LOCATION AND SIZE
Currituck National Wildlife Refuge is located in Currituck County in the northeastern corner of North
Carolina. The refuge is named for the county where it is located. The refuge’s approved acquisition
boundary lies entirely in Currituck County (population 18,190).
The city of Virginia Beach, Virginia (population 425,257) is about 27 miles north of the refuge. Other
nearby cities include Chesapeake, Virginia (population 199,184), 27 miles northwest; and Norfolk,
Virginia (population 234,403), about 31 miles northwest (Figure 1).
The refuge covers a total of 4,570 acres in fee title ownership and 3,931 acres in conservation
easements. It is bounded by Currituck Sound on the west; the Atlantic Ocean on the east; the city of
Virginia Beach on the north; and Dare County, North Carolina, on the south. This region is part of a
physiographic area known as the South Atlantic Coastal Plain. The area is also part of the Fish and
Wildlife Service’s administrative ecosystem known as the Roanoke–Tar–Neuse–Cape Fear Ecosystem.
ESTABLISHMENT
The refuge was established on August 2, 1983, by the Migratory Bird Conservation Commission
through the authority of the Migratory Bird Conservation Act of 1929. The Service established the
refuge’s approved acquisition boundary of 18,015 acres in 1981.
REFUGE HISTORY AND PURPOSES
ACQUISITION HISTORY
The Service acquired 1,770 acres in 1985 by fee simple purchase and 166 acres by conservation
easement. Since 1985, the refuge has acquired 2,800 additional acres in fee simple purchase for a
total of 4,570 acres. It has added 3,931 acres of conservation easements (Table 1).
PURPOSES
The purpose of Currituck National Wildlife Refuge, as reflected in the legislation under which
Congress authorized the refuge and the Service has acquired land, is to protect and conserve
migratory birds and other wildlife resources through the protection of wetlands, in accordance with the
following laws:
...for use as an inviolate sanctuary, or for any other management purpose, for migratory
birds... 16 U.S.C. Sec. 664 (Migratory Bird Conservation Act of 1929)
...for (1) incidental fish and wildlife-oriented recreational development, (2) the protection of
natural resources, (3) the conservation of endangered species or threatened species... 16
U.S.C. Sec 460k-1 (Refuge Recreation Act of 1962)
8 Currituck National Wildlife Refuge
Figure 1. Location of Currituck National Wildlife Refuge, Currituck County, North Carolina.
Comprehensive Conservation Plan 9
The North American Waterfowl Management Plan’s Atlantic Coast Joint Venture office, working
through a collaborative effort with private, state, and federal agencies, has established certain habitat
objectives for the physiographic area.
Table 1. Acquisition history of Currituck National Wildlife Refuge.
FEE SIMPLE ACQUISITIONS
YEAR TRACTS ACRES COST COST
ACRE
TOTAL
ACRES
TOTAL
COST
1984 1 17.97 $380,000 $21,146 17.97 $380,000
1985 1 1,747.78 $3,430,000 $1,962 1,765.75 $3,810,000
1988 1 54.21 $0 $0 1,819.96 $3,810,000
1997 3 1,576.28 $1,285,200 $815 3,396.24 $5,095,200
1998 2 889.64 $1,600,848 $1,799 4,285.88 $6,696,048
2003 1 284.00 $2,327,336 $8,195 4,569.88 $9,023,384
TOTAL 9 4,569.88 $9,023,384 $1,974
EASEMENT ACQUISITIONS
YEAR TRACTS ACRES COST COST
ACRE
TOTAL
ACRES
TOTAL
COST
1985 2 225.76 $120,000 $531 225.76 $120,000
1996 1 3,705.00 $0 $0 3,930.76 0
TOTAL 3 3,930.76 $120,000 $31 $120,000
Table 2. The Nature Conservancy ranking of vegetative communities of Currituck National
Wildlife Refuge.
Vegetative Community State Rank Global Rank
Maritime Evergreen Forest S1 G2
Maritime Swamp Forest S2 G2
Maritime Dry Grassland S2 G3
Tidal Freshwater Marsh S2 G4
Maritime Shrub S3 G4
S1 = Critically imperiled in North Carolina because of extreme rarity or otherwise very vulnerable to extirpation in the state.
S2 = Imperiled in North Carolina because of rarity or otherwise very vulnerable to extirpation in the state.
S3 = Rare or uncommon in North Carolina.
G1 = Critically imperiled globally because of extreme rarity or otherwise very vulnerable to extinction throughout its range.
G2 = Imperiled globally because of rarity or otherwise very vulnerable to extinction throughout its range.
G3 = Either very rare or local throughout its range, or found locally in a restricted area.
10 Currituck National Wildlife Refuge
SPECIAL DESIGNATIONS
The North Carolina Natural Heritage Program has designated most of the refuge, with the exception of the moist
soil management area, as a Significant Natural Heritage Area. The Nature Conservancy ranks certain
vegetative communities as imperiled or rare (Table 2).
The North Carolina Division of Water Quality has designated several water bodies in the vicinity of Currituck
National Wildlife Refuge as outstanding resource waters or high quality waters.
The North Carolina Division of Marine Fisheries has designated several streams and water bodies within and off
the borders of the refuge as anadromous fish spawning habitats.
ECOSYSTEM CONTEXT
Currituck National Wildlife Refuge lies within the South Atlantic Coastal Plain physiographic region
(Figure 2). The South Atlantic Coastal Plain was once a 25 million-hectare complex of forested
wetlands and uplands, dunes, and marshes that extended from Florida to North Carolina.
Historically, the extent and duration of seasonal flooding along the ecosystem’s rivers has fluctuated
annually, recharging the South Atlantic Coastal Plain’s aquatic systems and creating a rich diversity
of dynamic habitats that supported a vast array of fish and wildlife resources.
REGIONAL CONSERVATION PLANS AND INITIATIVES
Along with the Service’s legal mandates and initiatives, other planning activities directly influence the
development of the comprehensive conservation plan. Various groups and agencies develop and coordinate
planning initiatives involving regional, state, and local agencies; local communities; nongovernmental
organizations; and private individuals to help restore habitats for fish and wildlife on and off public lands.
The Service is initiating cooperative partnerships in an effort to reduce the declining trend in biological
diversity. Biological planning for species groups targeted in this plan reflect the North American Waterfowl
Management Plan, which includes the Atlantic Coast Joint Venture; the joint venture between the North
Carolina Wildlife Resources Commission and Fish and Wildlife Service; the Partners in Flight Plan; and the
South Atlantic Migratory Bird Initiative.
The Atlantic Coast Joint Venture focus is that of the middle and upper Atlantic coast. Within the Atlantic Coast
Joint Venture was the joint venture formed between the North Carolina Wildlife Resources Commission, Fish
and Wildlife Service, and private conservation organizations.
The South Atlantic Coastal Plain serves as a primary migration habitat for migratory songbirds returning from
Central and South America. It also provides wintering, breeding, and migration habitat for mid-continental wood
duck and colonial bird populations. Restoration of migratory songbird populations is a high priority of the
Partners in Flight Plan for the South Atlantic Physiographic Region.
The Partners in Flight Plan emphasizes land bird species as a priority for conservation. Habitat loss, population
trends, and the vulnerability of species and habitats to threats are all factors used in the priority ranking of
species. Further, biologists from local offices of the Service, the North Carolina Wildlife Resources Commission,
and conservation organizations such as the Audubon Society and The Nature Conservancy have identified focal
species for each habitat type from which they will determine population and habitat objectives and conservation
actions. This list of focal species, objectives, and conservation actions will aid migratory bird
management on the refuge.
Comprehensive Conservation Plan 11
Figure 2. Currituck National Wildlife Refuge in the South Atlantic Coastal Plain physiographic area.
12 Currituck National Wildlife Refuge
The Farm Bill programs administered by the U.S. Department of Agriculture each have state-level
plans and priority ranking systems in which the Service has input. For private landowners who own
lands in the vicinity of national wildlife refuges, the Service uses these programs to help them
manage habitat for wildlife or protect their lands with easements.
The North Carolina Wildlife Resources Commission has its own Comprehensive Wildlife Conservation
Strategy to help direct the state’s allocation of funds from the federally funded State Working Grants
Program. The Service has provided input to the development and execution of the strategy.
ECOLOGICAL THREATS AND PROBLEMS
HABITAT LOSS AND FRAGMENTATION
The South Atlantic Coastal Plain has changed markedly over the last 100 years as civilization spread
throughout the area. An estimated 40 percent of the coastal plain’s natural vegetation has been lost
to land conversion. The greatest changes to the landscape have been in the form of land clearing for
agriculture and urban development (Hunter et al. 2001).
Although these changes have allowed people to settle and earn a living in the area, they have had a
tremendous effect on biological diversity, biological integrity, and environmental health of the South
Atlantic Coastal Plain. Vast areas of bottomland hardwood forests have been reduced to forest
fragments ranging in size from very small tracts of limited functional value to a few large areas that
have maintained many of the original functions and values of forested values. Severe fragmentation
has resulted in a substantial decline in biological diversity and integrity. Species endemic to the
South Atlantic Coastal Plain that have become extinct, endangered, or threatened include the red
wolf and red-cockaded woodpecker (Table 3).
Breeding bird surveys show continuing declines in species and species populations. The avian
species most adversely affected by fragmentation include those that are area-sensitive (dependent
on large continuous blocks of hardwood forest); those that depend on forest interiors; those that
depend on special habitat requirements such as mature forests or a particular food source; and/or
those that depend on good water quality. Nest parasitism is also common in fragmented forests.
More that 300 species of breeding migratory songbirds are found in the region. Some of these,
including the Swainson’s warbler, prothonotary warbler, swallow-tailed kite, wood thrush, and
cerulean warbler, have declined substantially and need the benefits of large forested blocks to
recover and sustain their existence.
Fragmentation has also brought the forest edge and brown-headed cowbird (a seed-eating bird
common in agricultural areas) closer to the natural nesting sites of many forest interior-nesting birds.
The brown-headed cowbird is a parasitic nester that lays eggs in the nests of other birds, rather than
building a nest of its own. Nestling cowbirds are typically bigger and more aggressive, and out-compete
the young of the species building the nest. This results in poor reproductive success and
declining populations of forest interior-nesting species that are forced to nest near forest edges.
Fragmentation of bottomland hardwood forests has left many of the remaining forested tracts
surrounded by a sea of agricultural lands. Intensive agriculture has removed most of the forested
corridors along sloughs that formerly connected the forest patches. The loss of connectivity between
the remaining forested tracts hinders the movement of wildlife between tracts and reduces the
Comprehensive Conservation Plan 13
Table 3. Federally listed threatened and endangered animal species in the Coastal Plain of
North Carolina.
Region Status Common name Scientific Name
Coastal Plain Endangered Manatee, West Indian Trichechus manatus
Coastal Plain Endangered Sea Turtle, Hawksbill Eretmochelys imbricata
Coastal Plain Endangered Sea Turtle, Kemp’s Ridley Lepidochelys kempii
Coastal Plain Endangered Sea Turtle, Leatherback Dermochelys coriacea
Coastal Plain Endangered Stork, Wood Mycteria americana
Coastal Plain Endangered Sturgeon, Shortnose Acipenser brevirostrum
Coastal Plain Endangered Tern, Roseate Sterna dougallii
Coastal Plain Endangered Whale, Finback Balaenoptera physalus
Coastal Plain Endangered Whale, Humpback Megaptera novaeangliae
Coastal Plain Endangered Whale, Right Balaena glacialis
Coastal Plain Endangered Whale, Sea Balaenoptera borealis
Coastal Plain Endangered Whale, Sperm Physeter catodon
Coastal Plain Endangered Wolf, Red Canis rufus
Coastal Plain Endangered Woodpecker, Red-cockaded Picoides borealis
Coastal Plain Threatened Alligator, American Alligator mississippiensis
Coastal Plain Threatened Eagle, Bald Haliaeetus leucocephalus
Coastal Plain Threatened Plover, Piping Charadrius melodus
Coastal Plain Threatened Sea Turtle, Green Chelonia mydas
Coastal Plain Threatened Sea Turtle, Loggerhead Caretta caretta
Coastal Plain Threatened Silverside, Waccamaw Menidia extensa
functional values of many remaining smaller forest tracts. The lost connections also result in a loss of
gene flow. Restoring the connections to allow gene flow and reestablish travel corridors is
particularly important for some wide-ranging species such as the black bear.
ALTERATIONS TO HYDROLOGY
In addition to the loss of vast acreages of bottomland forested wetlands, substantial alterations have
occurred in the region’s hydrology due to managed stream flows from flood control and hydroelectric
power generation reservoirs; drainage ditches; river channel modifications; flood control levees;
deforestation; and degradation to aquatic systems from excessive sedimentation, contaminants, and
urban development.
The natural hydrology of a region is directly responsible for the connectedness of forested wetlands
and indirectly responsible for the complexity and diversity of habitats through its effects on
topography and soils. Natural resource managers recognize the importance of dynamic hydrology to
forested wetlands and waterfowl-habitat relationships (Fredrickson and Heitmeyer 1988).
14 Currituck National Wildlife Refuge
Instead of natural hydrology, large-scale, man-made hydrological alterations have changed the
spatial and temporal patterns of flooding throughout the entire South Atlantic Coastal Plain. In
addition, these alterations have modified both the extent and duration of annual seasonal flooding.
The alteration of this annual flooding regime has had a tremendous effect on the forested wetlands
and their associated wetland-dependent species. Specifically, the combination of managed stream
flows and drainage ditches in bottomland forests exposes the forests to more frequent flooding than
occurs naturally, drains the back swamps through natural levees, and floods the back swamps at low
flows through the ditches.
In view of the hydrologic changes, it is very difficult, if not impossible, to fully emulate and reconstruct
the structure and functions of a natural wetland. According to Mitsch and Gosselink (1993),
restoration of wetland functions is especially difficult because wetlands depend on a dynamic
interface of hydrologic regimes to maintain water, vegetation, and animal complexes and processes.
SILTATION OF AQUATIC ECOSYSTEMS
Aquatic systems, including lakes, rivers, sloughs and bayous, have been degraded as a result of
deforestation and hydrologic alteration. Clearing of bottomland hardwood forests has led to an
accelerated accumulation of sediments and contaminants in all aquatic systems. Many water bodies
are now filled with sediments, greatly reducing their surface area and depth. Concurrently, the non-point
source runoff of excess nutrients and contaminants is threatening the area’s remaining aquatic
resources. Turbidity caused by sediment limits light penetration into the water and consequently the
growth of submerged aquatic vegetation. The federal threatened and endangered species list for the
coastal plain of North Carolina includes four species of aquatic organisms that are listed as
threatened and 10 species that are listed as endangered.
Hydrologic alterations have basically eliminated the geomorphologic processes that created oxbow
lakes, sloughs, and river meander scars. Consequently, the protection, conservation, and restoration
of these aquatic resources take on an added importance in light of the alterations associated with
flood control and navigation.
PROLIFERATION OF INVASIVE AQUATIC PLANTS
Compounding the problems faced by aquatic systems is the growing threat from invasive aquatic
vegetation. Static water levels caused by the lack of annual flooding and reduced water depths resulting
from excessive sedimentation have created conditions favorable for the establishment and proliferation of
several species of invasive aquatic plants. Additionally, the introduction of exotic (nonnative) vegetation
capable of aggressive growth is further threatening the viability of aquatic systems. These invasive
aquatic plants threaten the natural aquatic vegetation important to aquatic systems, and choke
waterways to a degree that limits biodiversity and often prevents recreational use.
CONSERVATION PRIORITIES
The declines in the South Atlantic Coastal Plain’s dune, marsh, shrub, and forest communities and
their associated fish and wildlife resources have prompted the Service to designate the Currituck
Banks an area of special concern. A collaborative effort involving private, state, and federal
conservation partners is now underway to implement a variety of tools to restore the functions and
values of wetlands and other coastal habitats in the South Atlantic Coastal Plain. The goal is to
prioritize and manage areas to most effectively maintain and possibly restore the biological diversity
in the South Atlantic Coastal Plain. Some areas are prioritized as focus areas for intensive
management, others for reforestation, and still others for preservation.
Comprehensive Conservation Plan 15
Conservation agencies and organizations have initiated several coordinated efforts to set priorities
and establish focus areas to overcome the impacts of hydrologic changes and forest fragmentation.
Conservationists established a cooperative private–state–federal partnership, known as the North
American Waterfowl Management Plan, Atlantic Coast Joint Venture, in 1986 to help provide
sufficient wintering waterfowl habitat throughout the Atlantic Coastal Plain.
The initial Atlantic Coast Joint Venture effort for waterfowl has expanded to also establish breeding bird
objectives for shorebirds and neotropical migratory forest-nesting birds. The Atlantic Coast Joint Venture
is working with the U.S. Shorebird Conservation Working Group to establish step-down objectives for
shorebird foraging habitat for the fall migration period throughout the South Atlantic Coastal Plain.
Partners in Flight has developed bird conservation plans to focus a number of private, state, and
federal restoration programs into specific areas in an effort to provide maximum program benefits for
neotropical migratory songbirds. The goal of this collaborative restoration effort is to provide islands
or blocks of habitat, especially forested habitat, in an otherwise highly fragmented landscape. The
targeted block sizes range from 10,000 to 100,000 acres. Such areas are large enough to support
viable populations of various suites of neotropical migratory songbirds. Of course, these areas would
also support other species that depend on large forested blocks. Existing or proposed state wildlife
management areas or national wildlife refuges are the anchors of the plans. These public lands
serve as centers of biodiversity that landowners and managers enhance and support by the
expansion of forested blocks, either through public or private management.
One of the biggest challenges to the management and restoration efforts underway in the South
Atlantic Coastal Plain, and one that affects refuges in particular, is the need to meet long-term
management objectives that address comprehensive ecosystem needs, including those of wintering
migratory waterfowl, neotropical migratory birds, shorebirds, large mammals, and other wide-ranging
species. Often management for one species or species group conflicts with the management
objectives for another species or species group. The tendency is to pursue short-term priorities that
frequently change as scientific knowledge expands and interests in special resources shift. Agencies
and organizations must exercise caution to prevent the start-up of management and restoration
actions that are difficult to reverse and fail to meet the long-term, comprehensive management needs
of the ecosystem or a specific area within the ecosystem. An example might be a tendency to
suppress large areas of shrubs in an effort to provide habitat for species of neotropical migratory
songbirds that require a marsh habitat, such as the sharp-tailed sparrow and seaside sparrow. Such
an approach may overlook the critical habitat needs of other songbirds that prefer a scrub/shrub
habitat, such as the painted bunting.
The habitat goals of the Atlantic Coast Joint Venture can only be met through active management of
croplands, moist soil areas, and forested wetlands on both public and private lands (Reinecke and
Baxter 1996). Active management (i.e., vegetation manipulation and hydrology restoration) is
required to compensate for the spatial and temporal habitat changes that have been caused by
deforestation and hydrologic alterations throughout the South Atlantic Coastal Plain. When properly
managed, Currituck National Wildlife Refuge would make a substantial contribution to meeting the
objectives of the Atlantic Coast Joint Venture. Setting habitat and species objectives from the
perspective of the South Atlantic Coastal Plain is advantageous because it looks at the big picture
and enables managers to plan and provide habitat for a diversity of species throughout their range.
Although the management of marshes, shrub/scrub areas, and forest stands is probably the best
solution for restoring the vast forests that have been altered, it must be remembered that hydrology
(flooding) drives the ecological system in the South Atlantic Coastal Plain. The plant and animal
community throughout the South Atlantic Coastal Plain is dependent upon the hydrologic cycle. It
16 Currituck National Wildlife Refuge
is incumbent upon land managers to manage hydrology in an effort to restore the ecological
diversity that once characterized the South Atlantic Coastal Plain. Refuges can install
impoundments and structures to control and manage water in an effort to mimic historic flood
cycles and to meet wildlife habitat objectives.
PHYSICAL ENVIRONMENT
CLIMATE
Currituck National Wildlife Refuge exhibits a maritime climate because of its proximity to the Atlantic
Ocean and the surrounding bays and sounds. Winter temperatures on the average are milder than
those of mainland weather stations. The refuge’s summer temperatures are also cooler than those
on the mainland.
Because the flow of air over North Carolina is predominantly from west to east, the continental
influence is much greater on most of the state than the ocean or marine influence. Therefore, the
area experiences a fairly large variation in temperature from winter to summer.
The Gulf Stream current flows only a short distance off the North Carolina coast. One might think this
"river" of warm water would have a profound effect on the climate. Its direct effects are limited by the
fact that the prevailing winds in winter are westerly.
Lows usually reform along the coast as "Cape Hatteras lows" and then move north along the coast.
Winter's low-pressure storms are usually more intense because of the large north-to-south contrasts.
Winter storms bring prolonged periods of steady rain and are responsible for most of the winter
precipitation. The forms of precipitation in spring begin to change from steady rains to occasional
thunderstorms. The Gulf of Mexico's warm, moist air produces warm, humid weather throughout the
summer. Rainfall comes from occasional thunderstorms. Autumn, North Carolina's driest season, is
to many people the most pleasant, with its many clear, warm days and cool nights with little rain.
This weather usually lasts until November.
The study area is situated along a coastline with a long history of storm activity. Two basic storm
types present a substantial threat to the coastal zone. Tropical storms and hurricanes, spawned over
the warm ocean waters of the Gulf of Mexico and the Atlantic Ocean, are probably the best known
and feared storms. Hurricanes, which are characterized by winds greater than 75 miles per hour and
accompanied by intense rainfall, plague the Gulf and Atlantic seaboards from midsummer to late
autumn. During the 1950s, a total of nine hurricanes affected the North Carolina coastline. Since
then, only seven major hurricanes have occurred along the Outer Banks.
Most storms pass off the coast east of the Currituck National Wildlife Refuge, but many bring large
quantities of rain to the refuge. These extratropical storms, often called “northeasters,” present a
greater problem than hurricanes to the Atlantic coast, the Outer Banks in particular. Such storms
may develop as strong low-pressure areas and move slowly offshore into the Atlantic Ocean. The
winds, sometimes reaching hurricane force, blow onshore from a northerly or easterly direction for
sustained periods of time. The damage from these storms may ultimately far exceed the destruction
from a hurricane. The March 1962 “northeaster,” also known as the “Ash Wednesday Storm,” proved
that point decisively. The flood height and duration of extratropical storms often have equaled or
exceeded those of hurricanes affecting North Carolina.
Comprehensive Conservation Plan 17
Most North Carolina tornadoes occur in the Piedmont and the interior of the coastal plain, which
spares Currituck County.
The average annual precipitation is 46 inches, and the average annual snowfall is 3 inches. The
record daily snowfall was 14.2 inches at Norfolk, Virginia, and 25 inches at Elizabeth City, North
Carolina. Snow accumulations of more than one inch for more than a day are rare. Rainfall is evenly
distributed throughout the year; the average monthly rainfall ranges from 2.98 in November to 5.17 in
July. Ten months have an average precipitation between 3 and 5 inches. Of the total annual
precipitation, about 25 inches usually falls in April through September. The growing season for most
crops falls within this period.
The average relative humidity in mid-afternoon is about 60 percent. Humidity is higher at night, and
the average at dawn is about 85 percent. The sun shines 65 percent of the time in the summer and
60 percent in the winter. The prevailing wind is from the southwest. The average wind speed is
highest, 10 miles per hour, in the spring. The average daily maximum temperature is 68 degrees
Fahrenheit, and the average daily minimum is 51 degrees.
In January the average temperature is 40 degrees; the average daily minimum temperature is 32
degrees; and the average daily maximum is 48 degrees. In July the average temperature is 79
degrees; the average daily maximum temperature is 89; and the average daily minimum is 71.
The average growing season is 247 days long. The average last date of frost in the spring is March
20 and the first frost in the fall is November 23.
GEOLOGY
The northern Currituck Banks are part of an extensive coastal lowland that stretches from
Newfoundland southward to Florida, and westward into the Gulf of Mexico. The submerged portion
of this landmass, the continental shelf, varies in width from 300 miles off the coast of
Newfoundland, 150 miles off the middle Atlantic coast, and to less than five miles off the coast of
Florida. The emergent area of this land mass is the coastal plain, which extends from southern
New Jersey to Florida. These two units comprise the Atlantic Coastal Plain, a major physiographic
province (Fenneman 1938).
Continental Shelf. The continental shelf begins at the beach face where there is a steepening
of slope to a depth of about 30 feet. The gradient then decreases to approximately two feet per
mile until a depth of slightly over 100 feet is reached; then the gradient increases to
approximately one foot per 20 feet.
Coastal Plain. Pliocene and lower Pleistocene sediments in the Carolinas were deposited in several
distinct basins believed to be the result of structural downwarping, possibly due to reactivation of
older fault systems. These depocenters were the loci of marine embayments and are bounded by
arches over which less sedimentation has occurred. The major Pliocene–Pleistocene depocenter in
North Carolina, the Albemarle embayment, occupied most of northeastern North Carolina and
extended into southeastern Virginia (Ward et al. 1991).
The Coastal Plain Province lies east of the Piedmont Province. The boundary is the "Fall Line,"
which is a broad transition zone where the crystalline rocks of the Piedmont (i.e., the igneous and
metamorphic rocks that cause the rapids in the Roanoke River at Roanoke Rapids) become buried
by the marine sediments of the Coastal Plain. Near the western border of the coastal plain at
elevations greater than 270 feet, the depositions are different from those found farther east and are
18 Currituck National Wildlife Refuge
classified as high level gravels, sand, and clay, indicative of continental origin. Underlying the coastal
plain are older bedrock formations of Cretaceous age, overlain with deposits of sand and clay.
Below this elevation, the surface layers of sand and clays, which vary in thickness from 10 to 40 feet,
occur as belts 10 to 15 miles wide that lie at different elevations of sea level and extend in a
northeast–southwest direction across the region. It is commonly agreed that these are marine
terraces of Pleistocene origin (Oaks and Coch 1973). Each terrace is located at an elevation that
reflects the sea level at that time. Geologists have subdivided these terraces into more distinct ridges
and scarps to better reflect their respective morphology and stratigraphy.
The tidewater region is bounded on the west by the Suffolk scarp, which passes just west of the
Dismal Swamp in Virginia extending south into North Carolina, and on the east by a series of shallow
embayments. This region of the coastal plain is characterized by low, often poorly drained land
generally averaging less than 20 feet above sea level. The only other areas of greater elevation in
this region are sand ridges, such as the Pungo and Knotts Island ridges in Virginia, the Powells Point
ridge in North Carolina, and large sand hills located on the Currituck Banks.
Thin beds of Quaternary sediments were deposited on the surface of the Coastal Plain during the
past three million years (Riggs and Belknap 1988). This Quaternary history and the resulting surface
veneer of unconsolidated sediments directly dictates the general characteristics of the coastal plain,
including the regional morphology and character of the drainage systems and flooded estuaries, soil
types, and potential land use. Quaternary sediments were deposited by the coastal system, which
rapidly migrated back and forth across the coastal plain–continental shelf as the sea level fluctuated
in response to repeated episodes of glaciation and deglaciation. Within this rapidly changing coastal
system, extremely varied sediments (including gravel, sands, clays, and peat in all possible
combinations) were deposited in river, estuarine, barrier island, and continental shelf environments.
The Quaternary history continues today.
Barrier Islands. The last unit in the coastal plain physiography is the barrier island. These units
were formed when melting glaciers caused a worldwide rise in the sea level. Later, the slowing of
sea level rise set a combination of factors in motion to create barrier islands on the shallow shelf.
The bays and estuaries that have formed behind these barriers have become shallow, due to
sediments received from river systems draining the coastal plain and overwash from storm surges.
Along the Currituck Banks, inlets have periodically formed and reformed depending on the occurrence of
storms, amount of sedimentation, the tidal heights, and degree of vegetation of the barrier beach. These
inlets, when they were active, enabled the embayments to exist as true estuarine environments.
Theories of Barrier Island Formation. The Outer Banks barrier beach complex is of relatively
recent geologic origin. When the sea level began to rise at the end of the last glacial period (15,000
years ago), coastal processes began to create this barrier island complex. There are various theories
as to the method of formation of these islands. The earliest theories stated that barrier islands
formed as the ocean pushed up ridges of sand off the sea floor, with new islands continually forming
offshore (Johnson 1919).
Two other basic theories are presently being debated. Fisher (1962) has proposed that the barrier
islands began as spits located downdrift from eroding headlands. Hoyt (1967) maintains that the
barrier beach system formed during the last 5,000 years when the Holocene sea level rise slowed
down. Dune ridges had a chance to build up along a seashore that was some distance seaward of
the present coast. The rising sea then isolated the dune ridges from the mainland and lagoons or
embayments formed behind them.
Comprehensive Conservation Plan 19
It appears that the “multiple causality” approach introduced by Schwartz (1971), which proposes a
combination of factors, is the most valid of all proposed theories to date.
The formation of the Outer Banks represents a combination of several processes, with submergence
being the primary process.
Barrier Island Dynamics. Currituck Spit and the surrounding Outer Banks islands are primarily
perpetuated by the following processes: longshore currents, tides and tidal currents, wave action,
storm surges and wind action. These dynamic ongoing processes, coupled with sea level rise, cause
the shorelines and dune environments to undergo constant change. The adaptability of these islands
to constant physical change is a major part of their natural ecology (Godfrey and Godfrey 1976).
Unlike the much more stable interior lands such as the Appalachian Highlands and Piedmont, where
ecosystems have changed little for thousands of years, the entire barrier island system is less than
5,000 years old. Some alterations of the dune system can be measured in centuries with noticeable
changes occurring in mere decades. The Currituck Spit has undergone many physical changes,
such as barrier island migration, inlet formation, and marsh building.
Shorelines along the Currituck coast from Cape Henry to Oregon Inlet have undergone varying
degrees of erosion and accretion. Beach profile data for this area allows a comparison of recent
beach changes and historical changes. Sutton and Goldsmith (1976) showed historical shoreline
changes between Cape Henry and Cape Hatteras over the greatest period of time for which data is
available. Studies by Goldsmith et al. (1977) and Dolan et al. (1979) involving measurements of
beach profiles from Cape Henry to False Cape State Park, parallel the historic data and indicate
alternating areas of erosion and accretion. Additional data indicates that the coastline south of False
Cape State Park to Duck, North Carolina, also contains alternating areas of accretion and erosion.
Barrier Dunes. The Currituck Spit is 1-1/2 to 2 miles wide and extends from just south of Salt Pond
near Sandbridge, Virginia, to Oregon Inlet, North Carolina, a distance of 69 miles. Two linear chains
of dunes border the barrier beach along most of the coast. In Virginia, large portions of these dunes
have been stabilized since the late 1930s through Civilian Conservation Corps programs and various
state and federal dune maintenance programs. Elevations of dune crests typically range from 15 to
25 feet. A few large dunes such as Lewark Hill, north of Corolla, and Whalehead Hill, just south of
Corolla, exceed 60 feet.
Goldsmith has divided the dunes into four basic types (Goldsmith et al. 1977): vegetated dunes,
artificial or manmade dunes, medanos, and parabolic dunes.
Vegetated dunes form as sand accumulates around existing vegetation, which acts as a sand-trapping
baffle, and also as an internal skeleton fixing the dunes in place. This type of dune is
generally found in the foredune or frontal dune line. In the study area, the highest and most
prominent vegetated dunes are located at the north end of Virginia Beach (Cape Henry) and in False
Cape State Park where they reach 30 feet.
Artificially induced dunes have their origins in dune fencing, vegetation planting, bulldozing, and man-induced
sedimentation. Frequently, these types of dunes are accidental in origin. Sand builds around
beach homes, shipwrecks, or discarded vehicles. Municipalities and landowners in Currituck County use
dune fencing in an effort to slow wave erosion and protect homes built close to the beach. They also
carry out bulldozing on a small scale to prevent blowouts from forming on the frontal dunes.
Medanos are large isolated hills of sand, asymmetrical in profile and lacking vegetation. Within the
study area, the tendency of medanos is to migrate in a southwesterly direction. These dunes have
20 Currituck National Wildlife Refuge
characteristic slipfaces of unconsolidated sand facing the southwest. There are about 24 medanos in
Currituck County with elevations up to 75 feet, such as Lewark Hill, and with migration rates up to 40
feet per year, such as Jones Hill (1940–1975). The building of these medanos depends primarily on
wind direction and intensities. It is these dunes that have historically destroyed or interfered with
towns, roads, and maritime forests on the Outer Banks.
Parabolic dunes are similar to medanos in that they have a slipface formed in direct response to the
wind and have a deflation zone within their concave side. Unlike medanos, their internal geometry is
characteristic of vegetated dunes and is fixed in place. Parabolic dune complexes sometimes evolve
from unvegetated sand sheets and often from medanos. They occur in False Cape State Park and
also in southern Currituck County (Goldsmith et al. 1977).
Hennigar (1979) delineated a sequence of dune succession for Currituck Spit. Active, unvegetated sand
sheets first break up into discrete sand hills, which in turn are stabilized by vegetation. These sand hills
or medanos become semi-vegetated, large parabolic dunes. Dune fencing promotes this sequence by
creating a stable foredune that reduces sand supply to the interior of the spit. Portions of the study area
are presently in early stages of dune succession. Man’s influence on these dunes during certain
vegetation stages may be critical in affecting the stability of improvement within the area.
Wind Effects. The role of wind in both the erosion and accretion aspects of dune dynamics is
obviously critical. Wind is essential in the dune building as well as other long-term processes such as
barrier island migration and marsh formation. Prevailing winds on the Currituck Spit (north–northeast
in September–February and southwest from March–August) have greatly influenced the
establishment of an artificial frontal dune system in the Back Bay and False Cape area. Averaging
11.7 miles per hour throughout the year, winds have promoted dune succession by creating massive
dune complexes from unvegetated sand sheets. There are examples of this wind effect in Currituck
County. Some sand hills such as Barbour’s Hill (just north of the Virginia/North Carolina line) and
Whalehead Hill south of Corolla have migrated 2-1/2 feet per year and 18 feet per year, respectively
(Gutman 1978). The migration rate differences are due primarily to the degree of vegetation of each
hill and the supply of sediments. Besides sand movement within the barrier island complex, the
prevailing winds create “blowouts” or cut into the foredune in unvegetated areas, thus allowing
overwash during periods of storm surges. This can be detrimental or beneficial, depending on the
barrier protection philosophies.
Wave Effects. Waves, along with other environmental factors such as wind, currents, tides, storms, and
sea level rise, interact with the sand of the beach to form the complex and dynamic shoreline and beach
characteristics observed daily and seasonally. Sand transport, which is influenced by wave direction and
energy, is critical in both accretion and erosion processes along the study area coastline. Beach profile
studies, conducted during periods of both low wave activity and periods of higher wave activity including
storm surge, have confirmed the existence of alternating areas of erosion and accretion.
The overwash process is another factor of wave action. This process, defined as “continuation of the
uprush over the crest of the most landward (storm) berm” (Shepard 1973), is essential in the survival
of barrier islands during a period of slowly rising sea level. It allows the barrier island to “migrate” as
a unit by depositing sediments toward the rear of the island and often into the lagoon behind. Areas
along the foredune line that are weakened and/or lowered by blowouts and vehicular passage serve
as corridors for penetration of the overwash. During severe storms, such as in March 1962, large
sections of the barrier dune were flattened to form extensive washover flats with sediment being
deposited into bay waters. Portions of the coastline north of Corolla and north of the Dare County
line have been identified in The Currituck Plan for Outer Banks (1972) as areas of potential overwash
and termed unsuitable for development.
Comprehensive Conservation Plan 21
Inlet Areas. Inlets are temporary features that form when a spit or barrier island is breached by
severe storm surges. They are important both in the geomorphic evolution of the barrier island
complex and in the maintenance of the ecological productivity of estuaries. Although there are no
active inlets within the study area at the present time, several inlets have severed the Currituck Spit in
previous years. Of the five inlets that have been active along the spit, two relict flood tidal deltas can
easily be delineated. The relict delta of the “Old Currituck Inlet” is located on the west side of the
barrier island in the Carova Beach area. This inlet, which was the basis for establishing the original
North Carolina/Virginia boundary, migrated southward before closing in 1731.
The relict tidal delta for the “new Currituck Inlet” is located approximately four miles south of Carova
Beach. This inlet was active from 1713 to 1828. Potential inlet areas can be identified by the narrowness
of the barrier island, frequent overwash zones, and low profile foredune ridges (Fisher 1962).
SOILS
The soil types identified on the refuge are Corolla fine sand; Corolla and Duckston fine sands;
Currituck mucky peat;* Duckston fine sands; Duneland; Duneland and Newhan fine sands; Newhan
fine sands; Newhan and Corolla fine sands; Osier fine sand;* and Ousley fine sand (USDA Soil
Conservation Service 1982a, 1982b). Soils with an asterisk are listed as hydric in Hydric Soils of the
United States (USDA Soil Conservation Service 1985). Hydric soils are . . . "soils that in their
undrained condition are saturated, flooded or ponded long enough during the growing season to
develop anaerobic conditions that favor the growth and regeneration of hydrophytic (water-loving)
vegetation" (USDA Soil Conservation Service 1985) (Figure 3 and Table 4).
Most of the refuge is Currituck mucky peat, an organic soil with 60 inches of mucky peat and muck
over sand. It floods routinely with tidal fluctuations and has a water table from the surface to one foot
below the surface. Currituck soils support freshwater and brackish herbaceous marsh vegetation.
Duckston fine sands occur on the eastern edge of the Currituck soils. They have 72 inches of fine sand
with rapid permeability above the water table. They are somewhat poorly drained with water tables from
one to two feet below the surface. They flood more than once every two years, but only for two to seven
days. Duckston soils support shrub and herbaceous vegetation adapted to poor drainage.
Corolla fine sand and Newhan fine sand are well-drained soils that occur under the dunes on the
eastern edge of the refuge. Corolla fine sand occurs on the backsides of dunes and has 15 inches of
fine sand over sandy subsoil. The water table is one and a half to three feet below the surface.
Corolla soils support herbaceous dune vegetation that is adapted to good drainage, but not
necessarily tolerant of extremely droughty conditions. They are also excellent soils for building
construction, but are poor filters for septic systems.
Newhan fine sand occurs on low flats along the edges of freshwater marshes and has five inches of
fine sand over sandy subsoil. The water table is more than six feet below the surface. Newhan soils
also support herbaceous vegetation that is the most drought-tolerant and salt-tolerant. They are also
excellent soils for building construction, but are poor filters for septic systems.
Osier fine sand occurs on the tops of dunes and has 45 inches of fine sand over sandy subsoil. The
water table extends from the soil surface to one foot below the surface. Osier soils support woody
forest vegetation that is tolerant to high water tables. They are not suited for development.
Ousley fine sand occurs on flats near the sounds and has 80 inches of fine sand over sandy subsoil.
The water table is one and a half to three feet below the surface. Ousley soils also support woody
forest vegetation that is tolerant to high water tables. They are not suited for development.
22 Currituck National Wildlife Refuge
HYDROLOGY
The hydrologic setting of the Currituck Banks is similar to that of the Cape Hatteras area immediately
to the south. Studies of that area have shown that the fresh ground water reservoir on the Outer
Banks consists of two types of aquifers: an unconfined or water table aquifer that extends from the
land surface to the first confining beds of silt and clay, and a confined or semiconfined aquifer
beneath and between the silt and
clay beds. The water table aquifer ranges in thickness from 10 feet to 50 feet and averages 15 feet. The
water table altitude averages 3 feet above sea level along the narrower sections of the banks north of
Cape Hatteras and as high as 10 feet in the Cape area itself (Winner 1975).
Table 4. Characteristics of soils of Currituck National Wildlife Refuge.
Series Approximate
Acreage
Surface
Texture
Muck
Depth
Water
Table
Depth
Flooding
Frequency1 Vegetation
Currituck* 2,584 Mucky Peat 60” 0-+1’ Routine Marsh
Osier* 190 Fine Sand None 0-1 Common Forest
Duckston 300 Fine Sand None 1-2’ Frequent Shrub
Ousley 160 Fine Sand None 1.5-3 Common Forest
Corolla 440 Fine Sand None 1.5-3 Rare Dune Grass
Newhan 200 Fine Sand None 6+’ None Dune Grass
Beaches 225 Fine Sand None 6+’ None Dune Grass
Total 4,099
* - hydric soil that has wetland hydrology and will support wetland plants
1 = frequent = more than once every two years, common = likely under normal conditions,
rare = unlikely under normal conditions, none = not probable
Maintenance of the fresh groundwater on the Outer Banks depends on the amount of rainfall.
Measurements taken at Cape Hatteras indicate 55 inches per year. Because of the sandy nature of
the soil, rainfall enters the water table aquifer with little or no surface runoff except during periods of
intensive rainfall when the soil becomes saturated. Small intermittent fresh water ponds may then be
formed. At present, a few open fresh water ponds exist on the Outer Banks in Currituck County,
some of which are manmade and others exist as a result of barrier beach processes.
The deeper confined aquifers are as much as 30 feet thick and are below the first confining beds
whose thickness ranges from five to 20 feet. Exact thicknesses are difficult to define due to the
gradational nature of sediments below the water table aquifer.
The fresh groundwater on the Outer Banks may best be described as a lens-shaped mass floating on
top of denser salt water. The quantity of water in this fresh water lens changes depending on the
amount of recharge and discharge. Below the fresh water lens, a zone of diffusion occurs indicating
the fresh water–salt water interface. This zone periodically changes in response to flooding, tidal
movement, precipitation rates, and pumping rates.
Comprehensive Conservation Plan 23
Rainfall and Groundwater Recharge. In order to evaluate the availability of fresh groundwater on
the Outer Banks, it is necessary to examine the methods of recharging the system. Rainfall at Cape
Hatteras, south of the study area, averages 55 inches per year. At Norfolk, at the extreme northern
end, it averages 44 inches per year. Monthly water balances at Cape Hatteras show that May, June,
and July are water-deficit months, that is, there is insufficient rainfall or soil moisture to satisfy
potential evapotranspiration. These deficit months are also peak months for water demand all along
the barrier island because of the seasonality of water requirements. Rainfall during the months of
August and September restore water losses of previous months. The amount of precipitation
occurring from September to May is in excess of potential evapotranspiration losses and the result is
a surplus ranging up to 20 inches in Cape Hatteras. Because runoff is negligible, all of this surplus
water is used to charge the groundwater system.
Natural Groundwater Discharge. Natural discharge from the groundwater system occurs in two
ways: lateral movement toward the sounds and bays, and through soil evaporation and plant
transpiration. These two processes (soil evaporation and plant transpiration) are referred to
collectively as evapotranspiration and account for a return to the atmosphere of 33 to 35 inches of
rainfall per year on the Outer Banks.
When the rate of recharge is less than discharge, the lens of salt water underlying the barrier island
rises. This problem of saltwater intrusion is common in coastal communities.
Surface Water Resources. Because of their location along the Atlantic Coast, the Outer Banks are
extremely vulnerable to flooding from major storms. Overwash from these storms have in places
breached the entire barrier island and sent large volumes of salt water into the adjoining embayment.
Flooding has also occurred on the bay shoreline by wind tides, which frequently inundate low-lying
areas. These flooding and overwash processes can contaminate the groundwater table, depending
on salinity of overwash or floodwaters and amount of fresh water recharge following contamination.
WATER QUALITY
The Back Bay–Currituck Sound area is a highly productive ecosystem. Stretching from Sandbridge
in Virginia, south to Kitty Hawk, North Carolina, this embayment complex exhibits a brackish to fresh
wetland community.
Earliest references to this area indicate a true estuarine environment with inlets along the
Currituck Banks. When there were inlets, shellfish beds flourished and provided a market
access for harvestable marine resources.
In 1828, when the Currituck inlet closed along the northern portion of the Banks, the Back Bay–
Currituck Sound complex began its reversion to a brackish environment.
Since that closure, the area has periodically been subjected to “rapid” increases in salinity due to
beach overwash caused by major coastal storms. The last major increase in salinity occurred during
the Ash Wednesday Storm of 1962. This rapid increase of salinity to 75% of sea strength resulted in
massive fish kills and losses of aquatic vegetation important to waterfowl.
Following this major overwash, the salinity in portions of the Back Bay–Currituck area remained at
10–15% of seawater. Later as salinities decreased, the City of Virginia Beach instituted a pumping
program. Under this program, the city pumped seawater across the barrier beach into Back Bay in
order to reduce turbidity and increase the aquatic plant life. This pumping project attempted to keep
salinities between 5–6% of seawater.
24 Currituck National Wildlife Refuge
Figure 3. Soils of Currituck National Wildlife Refuge.
Comprehensive Conservation Plan 25
Records indicate that pumping maintained the salinities within this range until late 1974.
However, mechanical problems caused the program to operate intermittently after 1979, and
the city has since discontinued the program.
Information from local water quality control boards as late as 1978 indicate that the water of the Back
Bay–Currituck complex is that of high quality in an unpolluted, expansive, shallow, grassy brackish
embayment; however, recent concern has been expressed for agricultural/chemical pollution as a
possible source of disease outbreaks among fish populations.
Dissolved oxygen levels continue to exceed state water quality standards (5 mg/liter), with the
average being 7.5 mg/liter. Although this indicates a supersaturated condition due to photosynthetic
activity, there has been a slight decrease over the past few years.
The pH values observed (7.5 to 10.0 pH units) are indicative of high photosynthetic activity.
The bacteriological water quality has also been monitored to detect the presence of animal or human
waste contamination. Using the fecal coliform filter method, no colonies were counted in 159 of the
176 tests conducted (Jackson 1978).
The water quality on Currituck National Wildlife Refuge is related directly to the water quality in
Currituck Sound. The refuge staff maintains the impoundment waters through exchange with
Currituck Sound.
Developments and agricultural operations in the area located on hydric soils, nonhydric soils with
high water tables, or soils with rapid permeability all have the potential to pollute the water table with
septic system percolate, household wastes, and nutrients, pesticides, and petroleum products.
Recreational use of the sounds and bays also has the potential to impact water quality.
There is only one facility on the Outer Banks of Currituck County in the National Pollution Discharge
Elimination System (NPDES); the permit has had no violations. The State of North Carolina has
classified the water bodies around Currituck National Wildlife Refuge for minimum water quality
standards (Table 5). All water bodies and streams meet the standards established for the best uses.
The State of North Carolina lists no water body or stream surrounding the refuge as impaired.
Table 5. Classifications of water bodies and streams surrounding Currituck National Wildlife
Refuge.
Water Body or Stream Classification Best Uses
Currituck Sound
Knotts Island Bay
Knotts Island Channel
South Channel
Ships Bay
Raccoon Bay
SC – Saltwater Secondary Recreation, Fishing, Aquatic Life
26 Currituck National Wildlife Refuge
AIR QUALITY
In North Carolina, state law mandates that no source of air pollution shall cause any listed ambient air
quality standard (Section .0400) to be exceeded or contribute to a violation of any listed ambient air
quality standard (Section .0400) except as allowed by Rules .0531 or .0532 [.0401(c), NCAC, Title
15A, Subchapter 2D - Air Pollution Control Requirements (North Carolina Department of Environment
and Natural Resources)].
Subchapter 2D lists ambient air quality standards for sulfur oxides (measured as sulfur dioxide); total
suspended particulates; carbon monoxide; ozone; hydrocarbons; nitrogen dioxide; lead; and
particulate matter. Section .0508 enumerates control of particulates from pulp and paper mills.
Section 0.0520 (7) indicates that fires purposely set to forest lands for forest management practices
acceptable to the North Carolina Division of Forestry and the Environmental Management
Commission are permissible if not prohibited by ordinances and regulations of governmental entities
having jurisdiction. The regulation also includes a disclaimer that addresses certain potential
liabilities of burning even though permissible.
The area closest to the refuge that an environmental agency monitors is the Virginia Beach–Norfolk
metropolitan area. The Environmental Protection Agency monitors carbon monoxide, nitrogen
dioxide, ozone, sulfur dioxide and particulates in Norfolk, Virginia Beach, Hampton, Newport News,
Suffolk, and Chesapeake. Despite the large population with the industry, traffic, and power plants,
the area has exceeded only ozone level standards in 2002. Monitoring has indicated unhealthy
levels twice and unhealthy levels for sensitive groups thirteen times. The air quality is due to the
breezes blowing through the area from the ocean.
VISUAL RESOURCES/AESTHETICS
Currituck National Wildlife Refuge is part of an extensive complex of brackish marshes along the
Currituck Sound. The marshes are largely undisturbed and are protected by the federal government
at the Currituck, Mackay Island, and Back Bay national wildlife refuges; by the State of North Carolina
at the 2,958-acre Northwest Marsh Game Land and the 14,657-acre North River Game Land; by the
Commonwealth of Virginia at the 1,546-acre Princess Anne Wildlife Management Area, the 4,321-
acre False Cape State Park, the 3,441-acre North Landing River Natural Area Preserve, and the
2,417-acre Northwest River Natural Area Preserve; by the City of Virginia Beach at the North Landing
Park; and by The Nature Conservancy.
Visitors to the refuge have the opportunity to experience solitude, wildness, uninterrupted
quiet, spirit and adventure, and observe the signs and sounds of the marsh and forested
wetlands. Breezes off the water move the dune and marsh grasses like flags waving across
a vast landscape. During the growing season, the marshes appear alive with neotropical
songbirds, raptors, wading birds, marsh birds, mink, otter, and other wildlife species. The
forests of loblolly pine, red maple, black gum, sweetgum, green ash, and wax myrtle echo
the sounds of songbirds, wood ducks, and deer. During the late fall, winter, and early spring,
migrating waterfowl and songbirds fill the air in the managed wetlands, sounds, bays, and
streams with their sights and sounds.
Comprehensive Conservation Plan 27
BIOLOGICAL ENVIRONMENT
HABITAT
Currituck National Wildlife Refuge is a typical southeastern United States coastal barrier island
system that has formed dunes, brackish marshes and forested swamps in the Coastal Plain region.
Seabeach amaranth (Amaranthus pumilus) is the only plant species from the federal endangered
species list known to occur on the refuge. The National Wetlands Inventory describes the refuge as
an estuarine emergent herbaceous or palustrine, forested wetland with deciduous or broad-leafed
deciduous vegetation and a water regime ranging from temporarily flooded to semipermanently
flooded (Cowardin et al. 1979). Schafale and Weakley (1990) identify five natural communities within
the refuge boundary: dune grass, maritime dry grassland, maritime shrub, brackish marsh, and
maritime swamp forest. Other habitats have been altered or created by man. The National Wetlands
Inventory map delineates the refuge habitats (Figure 4). Vegetative communities on coastal barrier
islands are spatially distributed in a pattern relative to the location of the ocean and sound (Figure 5).
The large number of plant species listed in Appendix VI is indicative of the diverse habitats on the
refuge. Levy (1976) delineated 178 species representing 50 families and 132 genera in his study at
Duck, North Carolina. Hosier and Cleary (1979) listed over 200 plant species but felt that intensive
study would produce many more species. The vegetation communities present on the Outer Banks
include extensive dune systems, maritime grasslands, maritime shrub thickets, maritime forests, and
vast brackish marshes.
Man has had a substantial effect on the flora. Historic records suggest that livestock severely
overgrazed the barrier beach system in the 19th century, resulting in the mobilization of large sand
sheets (Hennigar 1979). Loggers have culled the forested areas numerous times in the past. That
culling undoubtedly changed the vegetative composition of the area.
The coastal processes discussed in the previous section further serve to shape the vegetative distribution
and diversity on the Banks. Local controlling factors, depth to water table, salt spray, substrate stability,
water salinity, and tidal effects contribute to the vegetative pattern that exists on the Banks.
Salt spray is one of the most critical of the coastal processes affecting vegetation on the barrier
system. Besides limiting the plant species along the beachfront, the spray serves to “deliver”
nutrients to those plants growing in the sandy soils of the beachfront. The “pruning effect” of the
spray on maritime shrubs and trees acts to tighten the tree and shrub canopy and provide shade
during periods of low rainfall and high evaporation, thus conserving the limited freshwater resources.
Beach
Unvegetated beaches occupy 202 of the refuge’s 8,501 acres and occur on the eastern edge of the
refuge above the normal high water elevation. These areas would be important nesting areas for colonial
nesting birds and sea turtles if there was authority to limit access to the beach below the normal high
water elevation. Extensive use of the beach for recreation discourages nesting efforts. Tire ruts would
limit successful movement of bird chicks and turtle hatchlings if they hatched successfully.
28 Currituck National Wildlife Refuge
Figure 4. National Wetland Inventory map of Currituck National Wildlife Refuge.
Comprehensive Conservation Plan 29
Figure 5. Profile of vegetative communities of coastal barrier islands.
Dune Grass and Maritime Dry Grassland
Dunes and grasslands occupy 137 of the refuge’s 8,501 acres and tend to occur in the eastern
section of the refuge. The dunes immediately west of the beach are dominated by American
beachgrass, bitter panicum, saltmeadow cordgrass, and sea oats. The grasslands west of the dunes
are dominated by saltmeadow cordgrass with goldenrod, Indian blanket, and many other forbs in
areas eroded by winds.
Dune Grass. The floral diversity and distribution on the North Carolina portions of the Currituck
Banks are interesting and complex. The barrier beach system is located in a transition zone between
northern and southern groups of plant species. The warm Gulf Stream waters turn offshore at Cape
Hatteras and the Labrador Current moves southward along the Currituck Banks, creating a zone
where northern species have their southern limits and southern species have their northern limits.
American beachgrass is near its natural southern limit, while sea oats is considered to be at the
northern limit of its range (Hosier and Cleary 1979).
Both American beachgrass and sea oats develop extensive horizontal and vertical rhizomes that
capture moisture from rainfall. These rhizomes further serve to bind sand and stabilize sand
surfaces. Beach grass and sea oats are adapted to tolerate stresses such as salt spray, overwash,
sand blast, and drought, all of which are characteristic of the foredune area (Seneca et. al 1977).
However, both species are extremely vulnerable to mechanical disturbance of the soils.
As the dunes are stabilized and conditions become more favorable, other species will invade the
strand community. Sea rocket, evening primrose, seaside goldenrod, beach pea, sandspurs, daisy
fleabane, and spurge are other common dune plants.
The width of the dunes varies along Currituck Banks. In those areas where artificial dunes have been
built, the berm crest and backslope often no longer exist or are severely eroded. Generally, those
areas with natural berms are wide, gently sloping and frequently overwashed by storm tides.
Currituck Soils Newhan, Duckston, and Corolla Soils
30 Currituck National Wildlife Refuge
Maritime Dry Grassland. Two basic types of terrestrial grasslands cover Currituck National Wildlife
Refuge. They are interdunal depressions and barrier flat grasslands. Interdunal depressions occur
where sand is moved from the surface forming a blowout. Mesic conditions, a relatively diverse flora,
and often standing water prevail in these areas. Barrier flat grasslands found on the overwash
terraces comprise the other terrestrial grassland community.
Interdunal depressions occur between the fore and back dunes along the seashore. The depressions
are “generally bowl-to-saucer shaped with semicircular-to-irregular perimeter” (Tyndall 1977).
Aeolian sand transport and oceanic overwash are the generative forces in the formation of these
depressions. The depth varies from just below to several feet above the water table. Floral
development is in response to the erosion of these depressions to or below the water table. Some
depressions possess standing water for varying amounts of the year.
A high diversity of plant species occurs in these depressions. At False Cape State Park and Back
Bay National Wildlife Refuge, both in Virginia, 129 species of plants were surveyed (Tyndall 1977).
Distribution and succession of these species are controlled by several abiotic and biotic factors,
including soil moisture, interspecific competition, salt spray, migratory waterfowl activity, and feral hog
disturbance (Tyndall 1977).
Dominant species in these depressions include salt meadow cordgrass, black needlerush, chair-maker’s
rush, and broom sedge. Other common herbaceous species include Centella asiatica, water
pennywort, aster, and water purslane.
Species on the perimeter of these depressions include groundsel tree, wax myrtle, bayberry, black
cherry, and live oak.
Availability of fresh water, diversity of seed-producing and food plants, as well as vegetative cover
provide habitat for many species of wildlife. Hosier and Cleary (1979) believe that these depressions
act as “reservoirs of genetic systems which, as conditions on the islands change, serve as a source
of new species for colonizing the new environments.”
The barrier flats begin on the backside of the beach berm and cover the flat overwash terraces. Salt
spray and overwash develop and maintain this community. It is common in areas where dunes are low
and have not been stabilized. The vegetation of this zone is adapted to withstand frequent storm tide
inundation and sand burial. Dominant species consist of grasses, sedges, and some forbs. Species
diversity on the flats adjacent to the beach berm is low. It is composed of salt meadow cordgrass,
seaside goldenrod, and sea rocket. In an area where overwash is less frequent, diversity and cover are
greater. In addition to the above-mentioned species are marsh fleabane, sandspurs, sea pink, and ladies
tresses. Godfrey and Godfrey (1976) described similar terraces on Cape Lookout National Seashore as
having greater than 50% cover and a standing crop of up to 1500 grams per square per year.
Dune buildup has occurred in several overwash passes and shrubs have invaded the terrace areas.
Sea elder, wax myrtle, groundsel tree are common species.
Maritime Shrub
Shrubs occupy 778 of the refuge’s 8,501 acres and tend to occur in the central part of the refuge
between the dunes and the marshes. The maritime shrub occurs along the length of the refuge on
areas that are naturally or artificially protected from oceanic influence. The buffering action provided
by the fore- and mid-dunes is essential for the establishment of this arborescent zone. Where salt
Comprehensive Conservation Plan 31
spray effects are the greatest, these species form a low spreading cover with many areas of maritime
grassland in between. Away from the ocean, in the shrub-dominated area, the growth pattern is low
and dense forming a closed canopy.
This community is dominated by wax myrtle, yaupon holly, American holly, groundsel tree, eastern red
cedar, and stunted live oak. The understory of greenbrier, Virginia creeper, grape, poison ivy, and
American beautyberry contributes substantially to its habitat value. The shrubs are sculpted by salt spray
and susceptible to wild fires that can temporarily return the area to an herbaceous stage of succession.
Cleared edges, roadways, and rights-of-way have been invaded by shrub thicket stands. This pattern
possesses large areas of “edge space,” a habitat that many wildlife species prefer.
Brackish Marsh
Brackish marshes occupy 2,202 of the refuge’s 8,501 acres and tend to occur on the poorly drained
peat soils in the western section of the refuge. Tidal flooding is rare and usually less than one foot.
Tides are generally wind driven with water levels dependent upon wind velocity and direction. Marsh
salinity is a function of the salinity of the overlying water (which varies between 2% and 20%), the
relative frequency and duration of inundation caused by oceanic overwash, periodic wind-flooding
waters, and the rate of flushing through the Currituck Sound (Odum et al. 1974). These wetlands are
classified as slightly to moderately estuarine intertidal areas that irregularly flood and support
persistent emergent vegetation (Cowardin et al. 1979).
The Northwest and North Landing rivers and Back Bay have high levels of dissolved oxygen,
nutrients, and detritus material that feed Currituck Sound. Coupled with the suspended materials
from periodic oceanic overwash, the marsh substrate provides a nutrient-rich area for plants.
These marshes are both physically and biologically important. The marshes of the sound act as
buffer strips, protecting the Outer Banks from erosion by waves on the sound side. Without the
marshes, the western shore of the Outer Banks would receive the full brunt of the waves. If not
protected, the slope of the barrier island western shore would cause the expenditure of the energy
contained in the waves over a smaller area. The higher the energy received in an area, the higher
the likelihood of erosion. The nearly flat plains of the marshes allow for large areas of dissipation.
Biologically, the marshes serve as important nesting and migrating grounds for numerous animal
species at all trophic levels. The vegetation allows for good forage and cover.
The marshes are dominated by black needlerush and saltmeadow cordgrass with big cordgrass and
seashore saltgrass in substantial quantities. With frequent fires, the black needlerush is suppressed
and the other grasses dominate.
The black needlerush occurs just above mean high tide in relatively pure stands. Other species found
with the needlerush include big cordgrass. The net primary productivity for needlerush marshes in Dare
County averages 478 grams per square meter per year (Stiven and Plotecia 1976). This amount of dead
or decaying marsh vegetation is contributed to the open estuary where it is utilized directly by consumer
organisms, including important fish and shellfish. While this figure is less than the productivity of the
smooth cordgrass marshes of Dare County, it is still important to the ecosystem.
The northern marshes exhibit a more heterogeneous composite of species including cattails,
arrowheads, seashore mallow, smartweeds, Olney three square, salt grass, chair-maker’s rush, and
black needlerush. No primary productivity data were available for this area; however, based on
related studies, productivity is assumed to be greater than the monotypic black needlerush stands.
32 Currituck National Wildlife Refuge
Maritime Forest
The maritime forest occupies 637 of the 8,501 acres and tends to occur in the central part of the
refuge between the dunes and marshes. Bellis and Proffitt (1976) defined the maritime forest
community of North Carolina as “all forested areas occurring in relict sand dunes either on the Outer
Banks or immediately adjacent to a permanently salty sound.” The maritime forest of the refuge is
generally located on the back dunes of the barrier beach system in areas not directly influenced by
storm-tide flooding and migrating dune systems.
The forest is dominated by swamp black gum, red maple, sweetgum, white ash, loblolly pine,
baldcypress, and water oak. It usually has a dense understory of wax myrtle, American hornbeam,
swamp red bay, stiff dogwood, and other shrubs. There is usually not a notable herbaceous understory.
Forests that are close to the ocean are low, generally less than 20 feet, and exhibit dense lateral
branching. This lack of apical dominance is caused by wind and salt spray. Dominant species
include live oak, red cedar, and laurel oak. Understory shrub species include American holly, black
cherry, poison ivy, Virginia creeper, and grape.
Forests that are further away from the ocean are taller (20 to 40 feet) and exhibit a more open canopy
that is structurally more diverse. Loblolly pine is a dominant member in this community, along with live
oak and American holly. Yaupon holly, hudsonia, greenbrier, and grape are common understory species.
Bellis and Proffitt (1976) found that the primary value of the maritime forest is that it helps reduce
erosion caused by storm surge and wave action. Other benefits of the forest include protection of
loose sandy soils from wind erosion; accumulation and storage of freshwater; mineral iron filtration;
production of soil by trapping blowing sand; deposition of humus; and wildlife habitat.
Conservation Easements
There are 3,931 acres of easements in the refuge’s 8,501 acres. These areas are predominately
open water and brackish marshes owned by hunting clubs. The refuge assists the hunting clubs in
managing the marshes with prescribed burning.
Managed Wetlands (Impoundments)
The refuge has 143 acres of impoundments that are managed to provide seed-producing herbaceous
vegetation for migrating waterfowl. The staff manages the water levels in the areas and discs the
vegetation to maintain early successional stage vegetation that produces the most seed. The staff
monitors the vegetation sporadically to assess the effectiveness of management (Table 6).
Threatened and Endangered Plants
The threatened seabeach amaranth (Amaranthus pumilus) is the only federally listed plant on the
refuge. The last citing was in 1989, when a biologist found a single plant on the refuge beach in
association with a threatened piping plover nesting colony. Disturbance from unrestricted vehicular
traffic on the beach destroys stands as they germinate. Seabeach amaranth also suffers from the
absence of washover habitat between and in back of the dunes.
Two plant species listed as threatened in the North Carolina Natural Heritage Program’s database
occur on the Outer Banks in Currituck County. One is the seabeach amaranth; the other is the
Carolina grasswort (Lilaeopisis carolinensis), an aquatic perennial herb.
Comprehensive Conservation Plan 33
Table 6. Vegetative composition of the Swan Island Moist Soil Unit.
Common Name Scientific Name Food
Value
Percent Composition
by Year
2002 2000 1994 1987 1986
Asian Pennywort Centella asiatica Fair 20.6 7.7 13.0 0.0 0.0
Buttonweed Diodia virginica None 12.9 0.2 8.5 15.2 10.7
Spikerush Elocharis
parvula
Good 12.4 27.2 0.0 0.0 0.0
Three Square Scirpus
pungens
Good 10.0 11.6 9.8 12.2 5.8
Water Hysop Bacopa spp. Good 8.7 1.5 4.5 9.4 0.7
Switchgrass Panicum
virgatum
Good 7.8 0.0 0.0 0.0 0.0
Fall Panicum Panicum
dichotomflorm
Good 6.5 0.5 0.0 0.0 0.0
Baldrush Fimbristylis spp. Fair 4.4 4.2 14.3 20.0 32.9
Smartweed Polygonum spp. Good 3.3 3.7 0.5 0.0 0.0
Cordgrass Spartina patens Fair 3.1 0.0 8.0 1.3 0.4
Water Primrose Ludwigia
palustris
None 0.0 7.3 0.3 0.0 0.0
Knotgrass Paspalum
distichum
Fair 0.6 5.6 3.3 12.7 4.4
Panicgrass Panicum spp. Fair 1.6 4.5 6.8 6.6 5.8
Foxtail Setaria spp. Good 0.3 0.0 4.8 5.1 4.2
Bermudagrass Cynodon
dactylon
None 0.0 0.0 4.3 8.4 8.6
Broomsedge Andropogon
virginicus
None 0.8 0.0 3.5 0.0 0.0
Rush Juncus spp. None 0.0 1.0 2.3 0.0 0.2
Pennywort Hrdrocotyle spp. Fair 0.4 1.2 0.3 4.1 0.5
Crabgrass Digitaria spp. Good 0.0 0.0 0.0 1.5 7.4
Total Good 61.2 45.5 20.4 30.7 19.2
Total Fair 27.7 24.0 46.7 44.0 44.2
Total None 11.1 30.5 32.9 25.3 36.6
Grand Total 100.0 100.0 100.0 100.0 100.0
34 Currituck National Wildlife Refuge
Thirteen species are listed as rare. Twelve occur in marshes: the marsh straw sedge (Carex
hormathodes); twig rush (Cladium mariscoides); toothed flatsedge (Cyperus dentatus); sand
spikerush (Eleocharis montevidensis); beaked spikerush (Eleocharis rostellata); riverbank quillwort
(Isoetes riparia); long-awned sprangletop (Leptochloa fascicularis var. maritima); awl-leaf mudwort
(Limosella australis); winged seedbox (Ludwigia alata); long beach seedbox (Ludwigia brevipes);
grassleaf arrowhead (Sagittaria weatherbiana); and pale mannagrass (Torreyochloa pallida).
Wooly beach heather (Hudsonia tomentosa) occurs behind the primary dune in open, sandy areas.
Insect and Disease Pests of Habitats
In recent years, the forest tent caterpillar has caused widespread defoliation in the state. Prolonged
flooding and saturation on coastal plain soils adversely impacts the parasitic wasp that preys on the
forest tent caterpillar. The parasitic wasp spends part of its life cycle in the ground. Prolonged
flooding kills the wasp so that it can no longer serve as a check on the populations of forest tent
caterpillar. This may account for the large outbreaks of forest tent caterpillars that resource
managers have been observing during the last decade on the coastal plain.
Another insect pest, the gypsy moth, is now well established as far south as northeastern North
Carolina. The North Carolina Division of Plant Industry and U.S. Forest Service closely monitor
gypsy moth populations. Both agencies use pheromone traps located throughout the state, including
refuge lands. When they detect large-scale outbreaks, they use integrated pest management
techniques to suppress the outbreak, but not necessarily eliminate the species from the area.
The southern pine beetle is becoming a more common pest of pines in northeastern North Carolina.
The beetles feed on the inner bark of stress-weakened trees. The needles turn yellow or straw-colored
within two or three weeks of the attack, before finally turning reddish-brown. Land managers
treat infected stands by cutting down a swath of trees around the area where the beetles are actively
feeding, thus removing their food and starving them. Managers must monitor their pine stands and
investigate any trees that appear infected.
WILDLIFE
The animal communities found on the refuge exhibit a low species diversity when compared to other
coastal areas. Two notable exceptions are the unusually large number of migrating hawks that pass
through the area each fall and the thousands of wintering waterfowl in Currituck Sound. Generally,
the fauna of this area consist of ecologically tolerant forms that are rather widespread in the coastal
plain, and some that are essentially statewide in distribution (Cooper et al. 1977).
The following sections discuss five general species groups: birds, mammals, reptiles and
amphibians, finfish and shellfish, and benthic invertebrates. Species lists are in Appendix VI.
Birds
The Outer Banks exhibit a great diversity and distribution of birds. This is due to many factors,
including the location of this area within the Atlantic Flyway and along the Gulf Stream.
Comprehensive Conservation Plan 35
Observations of raptors during fall migrations indicate that large numbers follow the Outer Banks,
notably accepters and falcons (Lee and Lee 1978; Ward 1976). Many other species such as migrant
warblers, shorebirds, gulls, terns, herons, and egrets use the Outer Banks as a migration corridor
during spring and fall migrations. Currituck Sound and the barrier beach system are important
wintering grounds for 23 species of waterfowl, as well as numerous other avian species. Additionally,
offshore winds and hurricanes undoubtedly bring transient species to the barrier beach system.
Located in the transition zone between northern and southern groups, the refuge is the northern
distribution limit for many southeastern coastal plain species. Additionally, species that are common
to the mainland (indigo bunting, bobwhite) as well as those common to the barrier beach system
(osprey, barn swallow) are represented on the refuge.
The variety of plant communities found on the refuge also contributes to the diversity and distribution
of bird life. As vegetative complexity and mass increase, so do available habitats. The forest/shrub
thicket communities support the majority of species on Currituck National Wildlife Refuge. This is due
in part to the layering effect of understory, woody vine, and shrub and forest vegetation.
The threatened bald eagle has nested on Mackay Island National Wildlife Refuge across the
Currituck Sound for the past seven years. Several species listed as high priority by the U.S. Fish and
Wildlife Service and/or listed by the state as rare and of special concern include the prairie warbler;
hooded warbler; black-throated green warbler; yellow-throated warbler; prothonotary warbler;
northern parula; sharp-tailed sparrow; northern bobwhite; king rail; solitary sandpiper; semipalmated
sandpiper; black tern; American black duck; American woodcock; short-eared owl; and American
kestrel, to name a few. The endangered red-cockaded woodpecker has been seen on rare occasion,
and the most recent sighting was more than 20 years ago. At least 182 species of birds, including 55
breeding species (16 migratory and 39 residential) use the refuge.
Wintering and migrating waterfowl make extensive use of the refuge's wetlands and the water bodies
surrounding the refuge. Factors that affect waterfowl distribution and population in Currituck Sound
include the overall Atlantic Flyway population, food availability, waterfowl disturbance, and local land use
trends (Sincock et al. 1965). Aquatic plant production affects the persistence of wintering waterfowl in an
area. The major change in aquatic plant production in Currituck Sound has been the growth of Eurasian
water milfoil. Florshutz (1972) reported the use of milfoil as a food source by twelve species of waterfowl,
most notably scaup, gadwall, and widgeon. A comprehensive survey of aquatic vegetation in Currituck
Sound is now underway. Growth of submerged vegetation, once felt to be sufficient for waterfowl
populations using the sound (Florshutz 1979), is now thought to be declining.
Disturbances that affect waterfowl distribution can take many forms, including boat activity and
hunting. Currituck Sound has 737 licensed waterfowl blinds, the majority being blinds on platforms
over the water (Snowden 1979).
Land use trends in surrounding areas have influenced the use of the sound by waterfowl. The
availability of corn and winter wheat is important to field feeders such as mallard and black duck, as
well as Canada and snow geese. Sincock et al. (1965) forecasted the effects of changes in agricultural
practices and the conversion of farmland to other uses on waterfowl use on Currituck Sound. The refuge
provides an area managed for moist soil vegetation that provides food and rest areas.
The Fish and Wildlife Service has identified areas that are of importance to wintering waterfowl in
general and wintering black ducks in particular. In both the Black Duck Coastal Wintering Habitat
Concept Plan and the Wintering Duck Concept Plan, the Service identified Currituck Sound as a
habitat warranting preservation for waterfowl (U.S. Fish and Wildlife Service 1975 and 1979).
36 Currituck National Wildlife Refuge
Principal species include the snow goose, tundra swan, mallard, wood duck, American black duck,
American widgeon, blue-winged teal, green-winged teal, ruddy duck, and northern pintail (Table 7).
The marshes surrounding Currituck Sound, Back Bay, and Knotts Island Bay provide habitat for a
substantial portion of the duck species in North Carolina.
Mammals
The mammal species composition for the refuge includes information from several sources, including
trapping data from biologists working in the area and information from the North Carolina State
Museum of Natural History. Nomenclature follows A Field Guide to the Mammals (Burt and
Grossenbeider 1964). Appendix VI lists 24 species of mammals on the refuge.
The distribution and diversity of mammal populations on the refuge are defined by several factors,
including habitat preference and/or dispersal ability of species and competition of native species with
introduced species. Introduced species often reduce diversity by forcing native species to adapt to a
wide range of ecological tolerances. For example, feral hogs (Sus scrofa) and horses (Equus
caballus) have overgrazed areas near Carova Beach to the elimination of habitat for native mammal
species. Other introduced species include nutria (Myocaster coypus), the house mouse
Mus musculus), and the Norway rat (Rattus norvegicus).
Table 7. Currituck National Wildlife Refuge waterfowl survey results, 2002-2003.
Species October November December January February
Gadwall 54 191 223 585
American Black Duck 94 205 92 182 268
Northern Pintail 8 270 290
Mallard 23 98 39 135 66
American Widgeon 42 104 10 78 80
Green-winged Teal 165 55
Hooded Merganser 11 1 5
Ring-necked Duck 11
Tundra Swan 1 325 875 722
Canada Goose 25 23 7
Total Ducks 332 472 605 673 1305
Grand Total 333 497 930 1571 2035
Habitat associations also influence the diversity and distribution of mammal species on Currituck
National Wildlife Refuge. As the vegetative complexity increases in general, so do the number of
species using the area.
Furbearers. The marshes on the backside of Currituck National Wildlife Refuge are valuable habitat
for several mammals. Factors that influence distribution and density of these species include salinity,
plant species present (for use as food and nest construction), depth and frequency of water
inundation, and local weather conditions (Brower et al. 1976). Species that are most valuable
commercially include muskrat, nutria, otter, and mink.
Comprehensive Conservation Plan 37
Feral Populations. Currituck National Wildlife Refuge supports a feral hog and horse population. No
population estimates were available for the hogs. In the past, hogs were released in the area that is
now False Cape State Park in the fall for grazing and collected in the spring. Collection of the hogs
was incomplete, resulting in the present feral population (Tyndall 1977).
Feral horses of uncertain origin inhabit the refuge. Some residents and others believe that these horses
have origins that date back to Spanish origins and indicate that these horses may have existed here for
over 400 years. Other sources indicate that these horses were brought to the island to avoid mainland
taxes and to provide summer grazing. Investigation of the genetics of the horses to determine the origin
of the horses has been inconclusive. Currituck County has passed an ordinance to protect the horses.
The county has also developed a group that advises the county commissioners on matters relating to
the maintenance of the wild horse herd. The Wild Horse Advisory Board is composed of two citizen
representatives and representatives from the Corolla Wild Horse Fund, the U.S. Fish and Wildlife
Service, and the National Estuarine Research Reserve. The approved Currituck Banks Wild Horse
Management Plan calls for the population of the horses to be maintained at or below 60 individuals. As
funding becomes available, the Service will study the effects of the horses on refuge lands and
incorporate recommendations based on the studies into the Currituck Wild Horse Management Plan.
Historically, grazing animals were left to forage wherever food was available; most of these animals
fed in the marshes and dunes as the forests were not particularly conducive to grazing. The result of
this grazing was the reduction of vegetation, encouraging the formation of sand sheets and sand hills,
destabilizing much of Currituck Banks (Hennigar 1979).
Evidence of grazing exists south of Carova Beach where a large area is devoid of vegetation.
The hog population has had a regressive successional effect on vegetation in the interdunal
depressions (Tyndall 1977).
Reptiles and Amphibians
Reptiles and amphibians represent two separate groups of vertebrates that are considered together
in this report. Forty-four reptiles occur on the Outer Banks in Currituck County, including 12 species
of turtles, 8 species of lizards, and 25 species of snakes. Thirty-three species of amphibians occur in
the area; 12 species are salamanders and 21 species are frogs and toads. A total of 77 species and
subspecies of reptiles and amphibians occur in the area. The rich herpetofauna of the Outer Banks is
explained, in part, by the diversity of habitats along the barrier beach system.
Examination of the distribution of refuge amphibians and reptiles reveals some geographic patterns.
Many species reach the northern limits of their ranges in eastern North Carolina. Included in this
category is the pinewoods snake, as well as other species. Many species occur only in the Atlantic
Coastal Plain and have their centers of distribution or the greater part of their ranges in North
Carolina. Included in this category are the many-lined salamander and Brimley’s chorus frog.
Though the herpetofauna is relatively well known, basic information on the distribution and ecology of
many species is lacking. Appendix VI lists the species present on the refuge.
Finfish and Shellfish
Ecologically dominant fish in the sound are represented by seven species. The species with the
largest number of fish per acre are yellow perch, tidewater silverside, pumpkinseed, and blue spotted
sunfish. The most important species on a weight per acre basis are carp, pumpkinseed, yellow
perch, largemouth bass, and golden-shiner (Borawa et al. 1979).
38 Currituck National Wildlife Refuge
Borawa et al. (1979) found that the length of largemouth bass is less at a given age than in the early
1960s. Additionally,