Merritt Island National Wildlife Refuge Comprehensive Conservation Plan

              Merritt Island National Wildlife Refuge
Comprehensive Conservation Plan
U.S. Department of the Interior
Fish and Wildlife Service
Southeast Region
August 2008
COMPREHENSIVE CONSERVATION PLAN
MERRITT ISLAND NATIONAL WILDLIFE REFUGE
Brevard and Volusia Counties, Florida
U.S. Department of the Interior
Fish and Wildlife Service
Southeast Region
Atlanta, Georgia
August 2008
Table of Contents i
TABLE OF CONTENTS
COMPREHENSIVE CONSERVATION PLAN
EXECUTIVE SUMMARY ....................................................................................................................... 1
I. BACKGROUND ................................................................................................................................ 3
Introduction .................................................................................................................................. 3
Purpose and Need for the Plan .................................................................................................... 3
U.S. Fish And Wildlife Service ...................................................................................................... 4
National Wildlife Refuge System .................................................................................................. 4
Legal Policy Context ..................................................................................................................... 5
National Conservation Plans and Initiatives ................................................................................. 6
Relationship to State Partners ...................................................................................................... 6
II. REFUGE ENVIRONMENT ............................................................................................................... 9
Introduction .................................................................................................................................. 9
Refuge History and Purposes ....................................................................................................... 9
Special Designations of the Refuge ........................................................................................... 13
Ecosystem Context ..................................................................................................................... 15
Regional Conservation Plans and Initiatives .............................................................................. 15
Ecological Threats and Problems ............................................................................................... 18
Physical Resources .................................................................................................................... 21
Climate .............................................................................................................................. 21
Geology and Topography .................................................................................................. 22
Soils ................................................................................................................................. 23
Air Quality .......................................................................................................................... 24
Hydrology and Water Quality ............................................................................................ 24
Biological Resources .................................................................................................................. 26
Habitat ............................................................................................................................... 26
Wildlife ............................................................................................................................... 37
Cultural Resources ..................................................................................................................... 45
Historical Overview ........................................................................................................... 45
Cultural Resource Protection ............................................................................................ 47
National Register ............................................................................................................... 47
Socioeconomic Environment ...................................................................................................... 48
Refuge Administration and Management ................................................................................... 53
Resource Protection .......................................................................................................... 54
Visitor Services ................................................................................................................. 58
Personnel, Operations, and Maintenance ......................................................................... 62
III. PLAN DEVELOPMENT ................................................................................................................. 65
Overview .................................................................................................................................... 65
Public Involvement and Planning Process ................................................................................. 65
Scoping of Issues and Concerns ................................................................................................ 67
Wildlife and Habitat Management ..................................................................................... 67
Resource Protection .......................................................................................................... 69
Visitor Services ................................................................................................................. 70
Refuge Administration ....................................................................................................... 71
ii Merritt Island National Wildlife Refuge
IV. MANAGEMENT DIRECTION ....................................................................................................... 73
Introduction ............................................................................................................................... 73
Vision ........................................................................................................................................ 73
Goals, Objectives, and Strategies .............................................................................................. 74
Wildlife and Habitat Management ..................................................................................... 74
Resource Protection ....................................................................................................... 109
Visitor Services ............................................................................................................... 114
Refuge Administration .................................................................................................... 127
V. PLAN IMPLEMENTATION .......................................................................................................... 139
Introduction .............................................................................................................................. 139
Funding Needs and Personnel ................................................................................................. 139
Research ................................................................................................................................. 143
Partnerships ............................................................................................................................. 144
Step-down Management Plans ................................................................................................ 144
Monitoring and Adaptive Management ..................................................................................... 145
Plan Review and Revision........................................................................................................ 145
APPENDICES
APPENDIX A. - GLOSSARY ............................................................................................................ 147
APPENDIX B. - REFERENCES ........................................................................................................ 163
APPENDIX C. - RELEVANT LEGAL MANDATES ........................................................................... 173
APPENDIX D. - BIOTA ..................................................................................................................... 175
APPENDIX E. - COMPATIBILITY DETERMINATIONS AND APPROPRIATE USE FORMS ......... 189
APPENDIX F. - HABITAT MANAGEMENT PLAN ........................................................................... 249
APPENDIX G. - VISITOR SERVICES PLAN .................................................................................... 251
APPENDIX H. - CONSULTATION AND COORDINATION .............................................................. 253
APPENDIX I. - LIST OF PREPARERS ............................................................................................. 259
APPENDIX J. PUBLIC INVOLVEMENT .......................................................................................... 261
Summary of Public Scoping ..................................................................................................... 261
Draft Plan Comments and Service Responses ........................................................................ 262
APPENDIX K. - FINDING OF NO SIGNIFICANT IMPACT ............................................................... 313
Table of Contents iii
LIST OF FIGURES
Figure 1. Refuge location and acquisition boundary ........................................................................... 10
Figure 2. Primary and secondary purpose areas, Merritt Island National Wildlife Refuge .................. 12
Figure 3. Federal agency boundaries in planning area ....................................................................... 14
Figure 4. North Florida Ecosystem ..................................................................................................... 16
Figure 5. Area conservation lands ...................................................................................................... 17
Figure 6. Impoundment Management Units ........................................................................................ 27
Figure 7. Burn units ............................................................................................................................. 28
Figure 8. Refuge vegetation ................................................................................................................ 29
Figure 9. Land use/land cover ............................................................................................................ 51
Figure 10. Aerial image ....................................................................................................................... 52
Figure 11. Status of properties on Merritt Island National Wildlife Refuge.......................................... 55
Figure 12. Status of Turnbull Creek Area ........................................................................................... 56
Figure 13. Existing visitor facilities and trails ...................................................................................... 57
Figure 14. Current waterfowl hunt areas ............................................................................................. 62
Figure 15. Current organization chart ................................................................................................. 64
Figure 16. Locations of Scrub Reserve Units ..................................................................................... 78
Figure 17. Impoundment management focus ..................................................................................... 86
Figure 18. Locations of citrus groves ................................................................................................ 105
Figure 19. Fallow groves selected for restoration to Florida scrub-jay habitat .................................. 106
Figure 20. Fallow groves to be restored to mesic hammock ............................................................ 107
Figure 21. Location of Bill’s Hill tract ................................................................................................. 111
Figure 22. Location of Tank Island .................................................................................................... 112
Figure 23. Existing and proposed visitor facilities ............................................................................. 115
Figure 24. Proposed additions to waterfowl hunt areas .................................................................... 117
Figure 25. Proposed deer and feral hog hunt areas ......................................................................... 119
Figure 26. Proposed public use zones .............................................................................................. 124
Figure 27. Proposed organizational chart ......................................................................................... 133
LIST OF TABLES
Table 1. Vegetation and cover types on Merritt Island National Wildlife Refuge ................................ 31
Table 2. Selected exotic species occurring on Merritt Island National Wildlife Refuge....................... 43
Table 3. Growth of resident and nearby counties from 1990–2000 (U.S. Census Bureau 2000b) ..... 48
Table 4. Growth of cities adjacent to refuge during 1990–2000 (U.S. Census Bureau 2000b) .......... 48
Table 5. Projected population growth for several area counties (Lenze 2002) ................................... 49
Table 6. Status of all properties within the refuge acquisition boundary ............................................. 54
Table 7. Acreages of Service-owned and managed lands and waters within the refuge
acquisition boundary ............................................................................................................. 57
Table 8. Acreages of federal lands in and around the refuge ............................................................. 57
Table 9. Refuge visitation data, 2003 ................................................................................................. 58
Table 10. Present and future disposition of citrus groves ................................................................. 108
Table 11. Current staff and annual costs .......................................................................................... 139
Table 12. Proposed staff and annual costs ....................................................................................... 140
Table 13. Step-down management plans and completion schedules ............................................... 145
iv Merritt Island National Wildlife Refuge
Executive Summary 1
Executive Summary
The U.S. Fish and Wildlife Service developed this Comprehensive Conservation Plan (CCP) and
Final Environmental Assessment (EA) to guide the management of Merritt Island National Wildlife
Refuge in Brevard and Volusia Counties, Florida. The plan outlines the refuge’s programs and
corresponding resource needs for the next 15 years, as mandated by the National Wildlife Refuge
System Improvement Act of 1997.
As part of the planning process, the Service conducted a biological review of the refuge’s wildlife and
habitat management program and a visitor services review of the refuge’s public use program. The
Service also held a series of eight public scoping and stakeholder meetings to solicit a wide range of
public opinions on the issues the plan should address. The comments and feedback from these
stakeholder and public scoping meetings, as well as those from the biological and visitor services
reviews, were considered and incorporated in the preparation of the Draft Comprehensive
Conservation Plan and Environmental Assessment (Draft CCP/EA). This Draft CCP/EA was
completed and made available for public review and comment for a period of 60 days, from
December 27, 2006 to February 26, 2007.
The Service developed and analyzed four alternatives. Alternative A was a proposal to maintain the
status quo, or no change from current management of the refuge. Under this alternative, the refuge
would continue to maintain 550 Florida scrub-jay family groups across 15,000 acres; 11–13 nesting
pairs of bald eagles; and 6.4 miles of sea turtle nesting beaches. Visitor services and facilities would
be continued at levels similar to those conducted in the past. No active management currently or in
the future would address resource protection issues. Coordination and partnerships with various
agencies would not reach their potential.
Alternative B proposed to expand refuge management for the needs of threatened and endangered
species. Under this alternative, the refuge would aggressively manage for Florida scrub-jays,
restoring and maintaining 19,000–20,000 acres in optimal condition to support 900 family groups.
Habitat management activities would be implemented to expand the number of nesting pairs of bald
eagles to 20, with increased protection of nest sites and development of artificial nesting platforms.
Visitor access would be limited and certain hunt areas would be reduced. The visitor experience
would be focused on the visitor center with fewer field opportunities. Resource protection would be
focused only on those habitats supporting threatened and endangered species. Coordination would
take on a more adversarial approach to protect key species.
Alternative C was a proposal to focus refuge management on the needs of migratory birds. Under
this alternative, current management activities for threatened and endangered species would remain
the same or would be decreased. The refuge would manage intensively for waterfowl, increasing the
size of the managed wetland impoundments to over 16,000 acres and annually support targets of 250
breeding pairs of mottled ducks; 60,000 scaup; 25,000 dabbling ducks; and 38,000 other diving
ducks. The refuge would also intensively manage for shorebirds, increasing to over 5,000 acres the
areas of impounded wetlands set aside for their use. Waterfowl hunting would be eliminated on the
refuge. Estuarine waters would be closed to boating activity. Coordination would take on a more
adversarial approach over impoundment management and reduced public use.
Alternative D proposed a more landscape view of the refuge and its resources, focusing refuge
management on wildlife and habitat diversity. The refuge would support 500–650 Florida scrub-jay
family groups with 350–500 territories in optimal condition across 15,000–16,000 acres. With active
management, the refuge would support 11–15 nesting pairs of bald eagles; maintain 6.3 miles of sea
2 Merritt Island National Wildlife Refuge
turtle nesting beaches; and maintain 100 acres of habitat for the southeastern beach mouse.
Manatee-focused management would be reestablished on the refuge. Several impoundments would
be managed for wood storks. The refuge would manage 15,000–16,000 acres of impounded
wetlands for waterfowl. More than 2,500 acres of wetlands would be managed for shorebirds and
another 1,500 acres would focus on wading birds. An increased effort to control exotic plants and
animals would be made. Coastal islands would be restored. Environmental education would be
increased, with greater emphasis on diversity of habitats and global warming. Coordination and
partnerships would be enhanced.
The Service selected Alternative D for implementation because it directs the development of
programs to best achieve the refuge’s purpose and goals; emphasizes a landscape approach to land
management; collects habitat and wildlife data; and ensures long-term achievement of refuge and
Service objectives. At the same time, its management actions provide balanced levels of compatible
public use opportunities consistent with existing laws, Service policies, and sound biological
principles. It provides the best mix of program elements to achieve the desired long-term conditions
within the anticipated funding and staffing levels, and positively addresses significant issues and
concerns expressed by the public.
Comprehensive Conservation Plan 3
I. Background
INTRODUCTION
The U.S. Fish and Wildlife Service (Service) developed this Comprehensive Conservation Plan (CCP)
to provide a foundation for the management and use of Merritt Island National Wildlife Refuge in
Brevard and Volusia Counties, Florida. The CCP is intended to serve as a working guide for the
refuge’s management programs and actions over the next 15 years.
The CCP was developed 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 in this CCP also meet the requirements of the National Environmental
Policy Act (NEPA) of 1969. Compliance with NEPA was achieved through the involvement of the
public and the development of an environmental assessment (EA), which describes the alternatives
considered and an analysis of the environmental consequences of the alternatives.
The CCP was prepared by a planning team composed of representatives from the refuge, the Florida
Fish and Wildlife Conservation Commission, and the Service’s Ecological Services Division (see
Appendix H, Consultation and Coordination). In developing this CCP, the planning team and refuge
staff incorporated the input of state agencies, other federal agencies, non-governmental organizations,
local citizens, and the general public through a series of stakeholder and public scoping meetings. This
public involvement and the planning process itself are described in Chapter III, Plan Development.
The CCP represents Alternative D, the Service’s preferred action alternative, and is being put forward
after considering three other alternatives, as described in the EA and summarized in the Executive
Summary. The preferred alternative is the Service’s recommended course of action for the
management of the refuge and is described in this CCP. While the CCP provides general guidance,
subsequent step-down plans will provide more detailed management direction and actions.
PURPOSE AND NEED FOR THE PLAN
The purpose of this CCP is to identify the role Merritt Island 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 CCP is needed to:
􀁹􇤠 provide a clear statement of direction for the future management of the refuge;
􀁹􇤠 provide refuge neighbors, visitors, and local, state, and federal government officials with an
understanding of the 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 and state laws; and
􀁹􇤠 provide a basis for the development of budget requests for the refuge’s operational,
maintenance, and capital improvement needs.
4 Merritt Island National Wildlife Refuge
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.
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. As part of its mission, the Service
administers the National Wildlife Refuge System, a national network of lands and waters established
for the management and protection of these resources.
NATIONAL WILDLIFE REFUGE SYSTEM
To date, the National Wildlife Refuge System is comprised of more than 540 national wildlife refuges
and over 3,000 small waterfowl breeding and nesting sites covering nearly 100 million acres, the
world’s largest collection of lands and waters specifically managed for fish and wildlife. The majority
of these lands, 77 million acres, is in Alaska. The remaining acres are spread across the other 49
states and several island U.S. territories. The mission of the Refuge System 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.”
National Wildlife Refuge System Improvement Act of 1997
The wildlife and habitat vision for national wildlife refuges stresses that wildlife come first; that
ecosystems, biodiversity, and wilderness are vital concepts in refuge management; that refuges must
be healthy; that the growth of refuges and the Refuge System must be strategic; and that the Refuge
System serves as a model for habitat management with broad participation from others. This broad
participation includes local, state, and federal government partners; organizations; the local business
communities; individuals; and volunteers. Volunteers continue to be a major contributor to the
success of the Refuge System and in 1999, some 36,000 of them contributed more than 1.3 million
hours on refuges nationwide, representing an economic value of more than $20 million.
The National Wildlife Refuge System Improvement Act of 1997 established, for the first time, a clear
legislative mission of wildlife conservation for the National Wildlife Refuge System. Activities were
initiated in 1997 to implement the direction of this new legislation, including an effort to complete
15-year comprehensive conservation plans for all refuges. These plans, which are conducted with
full public involvement, help guide the future management of refuges, including providing
management direction for the refuges’ natural resources and recreational and educational programs.
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;
Comprehensive Conservation Plan 5
􀁹􇤠 maintain the biological integrity, diversity, and environmental health of the Refuge System;
and
􀁹􇤠 recognize that wildlife-dependent recreational activities, including hunting, fishing, observing
wildlife, photographing wildlife, and participating in environmental education and interpretation,
are legitimate and priority public uses of national wildlife refuges.
The National Wildlife Refuge System hosts more than 37 million annual visitors. Economists found
that these refuge visitors contribute more than $400 million annually to local economies. In 2001 on
conservation lands throughout the nation, approximately 37.8 million people participated in wildlife-related
activities, most to observe wildlife in their natural habitats. These visitors represent nearly 40
percent of the country’s adults who spent $108 billion on wildlife-related pursuits in 2001, according to
the National Survey of Fishing, Hunting, and Wildlife-Associated Recreation (U.S. Department of
Interior, Fish and Wildlife Service, and U.S. Department of Commerce, U.S. Census Bureau 2001).
As visitation continues to grow on conservation lands and waters in general and specifically on
refuges, adjacent local communities are realizing economic benefits.
LEGAL POLICY CONTEXT
Administration of national wildlife refuges is guided by the mission and goals of the National Wildlife
Refuge System, congressional legislation, presidential executive orders, and international treaties.
Policies for management options of refuges are further refined by administrative guidelines
established by the Secretary of the Interior and by policy guidelines established by the Director of the
Fish and Wildlife Service. Management options are guided by a refuge’s establishing authorities,
Public Law 104, Stat. 2957 (§108, H.R. 3338), and the National Wildlife Refuge System Improvement
Act of 1997 (see Appendix C for more information on legal and policy guidance for the operation of
national wildlife refuges). Key guidance and direction can be found in:
􀁹􇤠 National Wildlife Refuge System Administration Act of 1966;
􀁹􇤠 Refuge Recreation Act of 1962;
􀁹􇤠 Title 50 of the Code of Federal Regulations;
􀁹􇤠 U.S. Fish and Wildlife Service Manual; and
􀁹􇤠 National Wildlife Refuge System Improvement Act of 1997.
Since refuges must be managed for wildlife first, lands and waters within the National Wildlife Refuge
System are closed to public uses unless specifically and legally opened under specified conditions
providing for compatibility with the refuges’ purpose(s). All programs and uses of a refuge must be
evaluated based on mandates set forth in the National Wildlife Refuge System Improvement Act,
including those that:
􀁹􇤠 contribute to ecosystem goals, as well as to refuge purpose(s) and goals;
􀁹􇤠 conserve, manage, and restore fish, wildlife, and plant resources and their habitats;
􀁹􇤠 monitor the trends of fish, wildlife, and plants;
􀁹􇤠 manage and ensure compatible wildlife-dependent visitor uses as those uses which benefit
the conservation of fish and wildlife resources and which contribute to the enjoyment of the
public (these uses include hunting, fishing, observing wildlife, photographing wildlife, and
participating in environmental education and interpretation); and
􀁹􇤠 ensure that visitor activities are compatible with refuge purpose(s).
6 Merritt Island National Wildlife Refuge
NATIONAL CONSERVATION PLANS AND INITIATIVES
In addition to the above laws and policies, numerous national landscape-level conservation plans and
initiatives also impact the management of the refuge’s resources, including those listed as follows:
􀁹􇤠 U.S. Department of the Interior, Fish and Wildlife Service Strategic Plan
􀁹􇤠 Wildlife Fire and Air Quality National Strategic Plan
􀁹􇤠 U.S. Fish and Wildlife Service, Fulfilling the Promise: The National Wildlife Refuge System
􀁹􇤠 North American Bird Conservation Initiative
􀁹􇤠 North American Waterfowl Management Plan
􀁹􇤠 North American Colonial Waterbird Conservation Plan
􀁹􇤠 Southeastern U.S. Region Waterbird Conservation Plan
􀁹􇤠 U.S. Shorebird Conservation Plan
􀁹􇤠 U.S. Shorebird Conservation Plan: Southeastern Coastal Plains-Caribbean Region
􀁹􇤠 Western Hemisphere Shorebird Reserve Network
􀁹􇤠 Partners in Flight Bird Conservation Plans
􀁹􇤠 Atlantic Coast Joint Venture Management Plan
􀁹􇤠 Atlantic Coast Joint Venture Waterfowl Implementation Plan
􀁹􇤠 North Florida Ecosystem Unit Management Plan for Fish and Wildlife Service Trust Resources
􀁹􇤠 Fish and Wildlife Service Florida Manatee Recovery Plan
􀁹􇤠 Fish and Wildlife Service Florida Scrub-jay Recovery Plan (in preparation)
􀁹􇤠 Fish and Wildlife Service Recovery Plan for Anastasia Island Beach Mouse and Southeastern
Beach Mouse
􀁹􇤠 Fish and Wildlife Service Recovery Plan for Leatherback Turtles (Dermochelys coriacea) in
the Caribbean, Atlantic, and Gulf of Mexico
􀁹􇤠 Fish and Wildlife Service Recovery Plan for the U.S. Population of the Atlantic Green Turtle
(Chelonia mydas)
􀁹􇤠 Fish and Wildlife Service Recovery Plan for the U.S. Population of Loggerhead Sea Turtle
(Caretta caretta)
􀁹􇤠 Recovery Plan for Marine Turtles. National Marine Fisheries Service
􀁹􇤠 Fish and Wildlife Service Southeastern States Bald Eagle Recovery Plan
􀁹􇤠 Fish and Wildlife Service Eastern Indigo Snake Recovery Plan
􀁹􇤠 Fish and Wildlife Service Revised Recovery Plan for the U.S. Breeding Population of the
Wood Stork
􀁹􇤠 Fish and Wildlife Service Atlantic Coast Piping Plover Recovery Plan
RELATIONSHIP TO STATE PARTNERS
The Fish and Wildlife Service is committed to encouraging and maintaining partnerships with others
to improve the environmental health of ecosystems and the National Wildlife Refuge System.
Partnerships are recognized by the Service as vital to fulfill its mission and help share advocacy for
fish and wildlife resources. Some of the current partners include federal and state agencies,
environmental organizations, outdoor sporting groups, industry, local governments, and private
landowners. 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.
Comprehensive Conservation Plan 7
Merritt Island National Wildlife Refuge’s state agency partners include the Florida Fish and Wildlife
Conservation Commission; Florida Department of Environmental Protection; Florida Division of
Forestry; Florida Inland Navigation District; and St. Johns River Water Management District.
Management of the state’s fish and wildlife is administered by the Florida Fish and Wildlife
Conservation Commission (http://www.floridaconservation.org/) and the Florida Department of
Environmental Protection (http://www.dep.state.fl.us/). These two agencies are charged with
enforcement responsibilities relating to migratory birds, trust species, and fisheries, as well as with
management of the state’s natural resources. Both agencies manage state lands and waters. The
Fish and Wildlife Conservation Commission manages 4.3 million acres of public lands and 220,000
acres of private lands for recreation and conservation purposes. The Department of Environmental
Protection manages 150 state parks covering nearly 600,000 acres and 57 coastal and aquatic
managed areas, totaling over 5 million acres of submerged lands and coastal uplands. In addition,
the St. Johns River Water Management District manages more than 260,000 acres in the Upper St.
Johns River Basin, with further acquisitions planned.
The various agencies within the state government have participated in a mix of refuge projects,
including the planning process to develop a 15-year CCP for the refuge. The State of Florida’s
participation and contribution throughout this comprehensive planning process have been valuable.
Many of the state agencies are continuing their work with the Service to provide for ongoing
opportunities and open dialogue to improve the ecological sustainment of fish and wildlife in Florida.
An integral part of the comprehensive planning process is the integration of common mission
objectives, where appropriate.
8 Merritt Island National Wildlife Refuge
Comprehensive Conservation Plan 9
II. Refuge Environment
INTRODUCTION
Merritt Island National Wildlife Refuge, located along Florida’s east central coast about 60 miles east
of the city of Orlando in Brevard and Volusia Counties, was established by agreement as an overlay
of the National Aeronautics and Space Administration’s John F. Kennedy Space Center (Figure 1).
The refuge covers a total of more than 140,000 acres and lies within one of the most productive
estuaries in the country, the Indian River Lagoon, which has more species of plants and animals than
any other estuary in North America (South Florida Water Management District 2005).
The refuge faces the Atlantic Ocean and includes three major water bodies that are all part of the
Indian River lagoon system: the Indian River Lagoon itself, Mosquito Lagoon, and the Banana River.
A growing human population, along with ongoing development and other human activities, currently
threatens the fragile but highly productive waters of the Indian River Lagoon system and the refuge.
The refuge derives its name from Merritt Island, which, along with Cape Canaveral, is a barrier island
complex that formed during the Pleistocene and Holocene periods. The complex is one of the last
extensive undeveloped barrier islands on the eastern coast of Florida. The lagoon’s location,
combined with its large size and other physical characteristics, make it one of the most diverse
estuaries in North America. As a result, a wide array of habitats exist on the refuge, including the
beach and dune system; estuarine waters; forested and nonforested wetlands; impounded wetlands;
and upland shrublands and forests. These diverse habitats support more than 1,000 species of
plants and more than 500 species of fish and wildlife, including a variety of waterfowl, shorebirds, and
neotropical migratory birds, as well as 93 federal- and state-listed species. Ten federally listed
threatened and endangered species regularly occur on the refuge.
Merritt Island National Wildlife Refuge was established on August 28, 1963, as the 286th refuge of the
National Wildlife Refuge System. According to the agreement with NASA, the lands and waters of
the Kennedy Space Center are primarily to serve the space program and secondarily to serve as a
wildlife refuge or park.
The refuge’s primary habitat management activities involve applying prescribed fire, using mechanical
treatments in upland scrub, employing chemical control of exotic plants, and managing water levels in
impounded wetlands. Low-intensity prescribed burning activities help to enhance and maintain
vegetative communities that are dependent upon or positively influenced by fire, for the benefit of
wildlife; to promote nutrient cycling; and to reduce an unnatural buildup of fuels that could otherwise
create hazardous, high-intensity wildfires. Among 76 impounded wetlands of the refuge, water levels
in 33 are seasonally manipulated to benefit migratory waterfowl, wading birds, shorebirds, and other
wildlife. The other wetlands are managed for fisheries and restoration. Additional upland
management activities include the periodic thinning of pine flatwoods to enhance nesting habitat for
bald eagles, as well as the control of exotic, invasive, and nuisance species.
REFUGE HISTORY AND PURPOSES
By 1962, the National Aeronautics and Space Administration had purchased most of the northern
portion of the barrier island known as Merritt Island in order to launch rockets into space. Located
adjacent to the U.S. Air Force’s Cape Canaveral Air Force Station, the new site was named the John
F. Kennedy Space Center. Sufficient lands to serve as safety and security buffer zones in order to
10 Merritt Island National Wildlife Refuge
Figure 1. Refuge location and acquisition boundary
Comprehensive Conservation Plan 11
launch the heavy lift booster rockets for manned space exploration were acquired through fee title
purchases, condemnation, and negotiation with the State of Florida for state lands and waters. On
August 28, 1963, the Fish and Wildlife Service entered into a cooperative agreement with NASA to
establish the Merritt Island National Wildlife Refuge, where space operations have priority. In this
initial interagency agreement, NASA transferred management authority to the refuge for only a
portion of the Kennedy Space Center’s lands and waters. This agreement authority was expanded in
the latter 1960s and by 1972 it included all nonoperational areas of the space center. A new updated
agreement between NASA and the Service was signed by both parties in May 2002. The most
recent agreement reflects the changes in operations of the two agencies and the coordination
procedures that have occurred over time.
On April 2, 1975, Congress established the Canaveral National Seashore. This act transferred
management responsibility of Playalinda Beach and approximately 1,000 acres north of the Gomez
Grant Line to the National Park Service. At the same time, approximately 34,345 acres in and around
Mosquito Lagoon were designated as a joint management area between Park Service and the Fish
and Wildlife Service. Natural resource management of much of the joint jurisdiction area remained
under refuge management, while the Park Service assumed management of all cultural resources in
this overlap area. Generally, the Seashore manages those areas in the refuge/Seashore overlap
east of the beach or sand road and the refuge manages the remainder of that overlap.
Due to its nature as an overlay of the Kennedy Space Center and its unique location and resources,
the refuge has two traditional purposes, as well as an additional purpose stemming from legislation
that created a unit of the National Park Service. Recognizing the high migratory bird benefits served
by the lands and waters of the refuge, the Service administratively designated Merritt Island Refuge
in 1963 under the provisions of the Migratory Bird Conservation Act, outlining a primary purpose of
these lands and waters:
"... for use as an inviolate sanctuary, or for any other management purpose, for migratory
birds."
16 USC §715d (Migratory Bird Conservation Act)
Further reading of the Migratory Bird Conservation Act also recognizes benefits to other species,
including those designated threatened or endangered:
“... to conserve and protect migratory birds ... and other species of wildlife that are listed ...
as endangered species or threatened species and to restore or develop adequate wildlife
habitat.”
16 USC §715i (Migratory Bird Conservation Act)
The refuge’s primary purpose applies to all lands and waters managed by the refuge, regardless of
when they were added to the refuge (see Figure 2). Since the refuge has management agreements
with NASA and the State of Florida, the lands and waters under those management agreements are
also subject to the conditions of those agreements.
In 1995, under the authority of the North American Wetlands Conservation Act, the refuge and its
partners began purchasing additional lands and waters in the northwest corner of the refuge, the
Turnbull Creek area:
“(1) to protect, enhance, restore, and manage an appropriate distribution and diversity of
wetland ecosystems and other habitats for migratory birds and other fish and wildlife in North
America; (2) to maintain current or improved distributions of migratory bird populations; and
12 Merritt Island National Wildlife Refuge
Figure 2. Primary and secondary purpose areas, Merritt Island National Wildlife Refuge
Comprehensive Conservation Plan 13
(3) to sustain an abundance of waterfowl and other migratory birds consistent with the goals of
the North American Waterfowl Management Plan and the international obligations contained
in the migratory bird treaties and conventions and other agreements with Canada, Mexico,
and other countries.”
16 USC §4401(2)(b) (North American Wetlands Conservation Act)
This secondary purpose applies only to those lands and waters of the Turnbull Creek area of the
refuge (Figure 2), whether owned by the Service or managed under some sort of agreement as
part of the refuge. However, the primary purpose also applies to the lands and waters of the
Turnbull Creek area. Again, since the refuge has management agreements with the State of
Florida for lands and waters in the Turnbull Creek area, those lands and waters are also subject
to the conditions of those agreements.
Congruent to the discussion of the traditional purposes of the refuge is the congressional enabling
legislation in 1975 that established Canaveral National Seashore as a unit of the National Park
Service. Congress established a national seashore partially on new lands and waters and partially as
an overlay of NASA’s Kennedy Space Center on lands and waters that were already being managed
as part of Merritt Island National Wildlife Refuge. In the legislation, Congress outlined that the
majority of the overlay portion of the Seashore would be managed as a refuge. The overlay area
encompasses approximately 34,345 acres and includes southern Mosquito Lagoon. Figure 3 shows
the complex land ownership and management picture for this area. The Seashore was established
“... to preserve and protect the outstanding natural, scenic, scientific, ecologic, and historic values ...
and to provide for public outdoor recreation use and enjoyment of the same ... the Secretary shall
retain such lands in their natural and primitive condition, shall prohibit vehicular traffic on the beach
except for administrative purposes, and shall develop only those facilities which he deems essential
for public health and safety” [16 USC 459(j)]. This language applies much as a wilderness
designation might apply, making this a secondary purpose for the 34,345 acres in the overlap area.
SPECIAL DESIGNATIONS OF THE REFUGE
The refuge holds several special designations. The State of Florida has designated numerous
national parks, a national memorial, national wildlife refuges, state parks and recreation areas, state
preserves and reserves, and other waters as Outstanding Florida Waters for their exceptional
ecological values and water quality. The Merritt Island Refuge was designated an Outstanding
Florida Water in 1979. In 1997, the refuge was designated under the Magnuson-Stevens Act as
Essential Fish Habitat to conserve and enhance the habitats necessary for fish to carry out their life
cycles. In 1994, Brevard County designated the refuge an Honorary Historic Landmark. Managed by
the Florida Fish and Wildlife Conservation Commission, the Great Florida Birding Trail is a collection
of sites throughout Florida that serve as excellent birdwatching sites and/or bird education
opportunities. Due to the refuge’s importance to resident and migratory birds, the refuge was
designated in 2000 as one of three gateways to the eastern section of the Great Florida Birding Trail,
which generally extends from the Florida-Georgia border in Nassau County to south of Fort Pierce
and from the Atlantic Ocean to west of Ocala. Also in 2000, the refuge was listed as a candidate
Marine Protected Area for its protection of estuarine waters. Since the Marine Protected Area system
is currently being designed, this designation holds the potential to benefit and/or constrain refuge
management activities. Further, the State of Florida has also expressed concern regarding the
impacts to management of such a designation. The Service is working with the Department of the
Interior, the President’s Marine Protected Area advisory council, the state, and other agencies
regarding the designation of marine protected areas. In 2001, the American Bird Conservancy
recognized 500 sites worldwide as Globally Important Bird Areas, including 183 national wildlife
refuges, such as Merritt Island National Wildlife Refuge.
14 Merritt Island National Wildlife Refuge
Figure 3. Federal agency boundaries in planning area
Comprehensive Conservation Plan 15
ECOSYSTEM CONTEXT
Comprising one of the 52 ecosystems around the country, the Fish and Wildlife Service’s North
Florida Ecosystem includes portions of southern Georgia and most of northern and central Florida
(Figure 4), spanning 33 Florida counties and 19 Georgia counties. The North Florida Ecosystem
includes several important areas with protective designations, including Ocala National Forest and
Okefenokee and Merritt Island national wildlife refuges. In total, thirteen national wildlife refuges and
one national fish hatchery occur in the North Florida Ecosystem.
Various other local, state, and federal conservation areas are also located within the North Florida
Ecosystem. The North Florida Ecosystem spans temperate and subtropical climates, numerous
physiographic districts, and a wide variety of habitats. Barrier islands, xeric scrub, pine flatwoods,
freshwater marshes, lakes, streams, springs, mixed hardwood/pine forests, cypress swamps and
domes, dry prairies, maritime forests, hardwood hammocks, estuarine marshes, pine rocklands,
sandhill woodlands, coastal strands, sawgrass prairies, sloughs, and tree islands of the North Florida
Ecosystem serve a variety of native wildlife, including over 100 federally listed species, as well as
interjurisdictional fishes, neotropical migratory birds, nongame waterbirds, and waterfowl.
The biggest problem facing the North Florida Ecosystem is the loss of habitat through direct destruction
and fragmentation, as well as through impacts from human activities. The predominant stresses for the
North Florida Ecosystem are population growth; tourism; agriculture; silviculture; mining; water
channelization; urbanization; aquifer depletion; fire suppression; exotic species; nonpoint source
pollution; and point source pollution (U.S. Fish and Wildlife Service 1996). The actions of the North
Florida Ecosystem Team are guided by two categories: trust resources and management issues. The
trust resources include: migratory birds, anadromous fish, endangered species, and marine mammals.
The management issues focus on habitat protection and management, habitat restoration,
contaminants, regulatory compliance, law enforcement, and biodiversity.
To address these threats, the management issues, and the needs of the trust resources, the North
Florida Ecosystem Team pursues a mix of objectives under five goals:
􀁹􇤠 Goal 1: Protect, conserve, and enhance migratory birds and their habitats in the North Florida
Ecosystem;
􀁹􇤠 Goal 2: Protect, conserve, recover, and restore fish, aquatic species, and their habitats in the
North Florida Ecosystem;
􀁹􇤠 Goal 3: Protect, conserve, and enhance wetlands in the North Florida Ecosystem;
􀁹􇤠 Goal 4: Protect, conserve, enhance, and recover listed and candidate threatened and
endangered species and their habitats; and
􀁹􇤠 Goal 5: Protect and manage units of the National Wildlife Refuge System and the National
Fish Hatchery System (U.S. Fish and Wildlife Service 1996).
REGIONAL CONSERVATION PLANS AND INITIATIVES
To address these and other threats and management issues, several regional-level conservation
plans and initiatives also impact the refuge’s resource management activities, including those listed
below (Figure 5 outlines the conservation lands around the refuge):
􀁹􇤠 Indian River Lagoon Surface Water Improvement and Management Plan, SJRWMD
􀁹􇤠 Indian River Lagoon Comprehensive Conservation and Management Plan, SJRWMD
16 Merritt Island National Wildlife Refuge
Figure 4. North Florida Ecosystem
Comprehensive Conservation Plan 17
Figure 5. Area conservation lands
18 Merritt Island National Wildlife Refuge
􀁹􇤠 Indian River Lagoon North Feasibility Study, Comprehensive Everglades Restoration Plan,
U.S. Army Corps of Engineers and SJRWMD
􀁹􇤠 Mosquito Lagoon Aquatic Preserve Management Plan, Florida Department of Environmental
Protection
􀁹􇤠 Banana River Aquatic Preserve Management Plan, Florida Department of Environmental
Protection
􀁹􇤠 NASA’s Facilities Master Plan for John F. Kennedy Space Center
􀁹􇤠 Cape Canaveral Spaceport Master Plan
􀁹􇤠 Future land use plans of Brevard and Volusia Counties
􀁹􇤠 City of Titusville Future Land Use Plan
􀁹􇤠 State of Florida Greenway Plan
􀁹􇤠 South Atlantic Marine Fisheries Council Fisheries Management Plan
􀁹􇤠 South Atlantic Marine Fisheries Council Ecosystem-Based Fisheries Management Plan
􀁹􇤠 General Management Plan, Canaveral National Seashore, National Park Service
􀁹􇤠 Resource Management Plan, Canaveral National Seashore, National Park Service
􀁹􇤠 Florida’s Wildlife Legacy Initiative – Comprehensive Wildlife Conservation Strategy: Planning
for the Future for Florida’s Wildlife, Florida Fish and Wildlife Conservation Commission
􀁹􇤠 45th Space Wing Integrated Natural Resources Management Plan, Cape Canaveral Air Force
Station, U.S. Air Force
ECOLOGICAL THREATS AND PROBLEMS
Merritt Island National Wildlife Refuge is in a key location, not only to serve and support the biological
diversity of the Indian River Lagoon and central Florida, but also to serve continental migratory bird
populations along the Atlantic Flyway. Human impacts and underlying threats to biological diversity
on and off the refuge include:
􀁹􇤠 the direct loss of habitat due to development and other human activities;
􀁹􇤠 the simplification and degradation of remaining habitats, including habitat alteration and
fragmentation;
􀁹􇤠 the loss and decline of species and biological diversity;
􀁹􇤠 the effects of constructing navigation and water diversion facilities;
􀁹􇤠 the introduction and spread of exotic, nuisance, and invasive species;
􀁹􇤠 the lack of environmental regulation and enforcement;
􀁹􇤠 the cumulative effects of land and water resource development projects;
􀁹􇤠 the ongoing wildlife disturbance due to development and other human activities;
􀁹􇤠 the impacts of nonpoint sources of pollution and water quality degradation; and
􀁹􇤠 the impacts of sea level rise and global warming.
As a result of these threats, some species endemic to the northern Indian River Lagoon have become
extinct, endangered, or threatened. The refuge supports 10 federally threatened or endangered
species that regularly occur on the refuge. Further, the refuge also supports an additional 47 species
listed by the State of Florida as either threatened, endangered, of special concern, or commercially
exploited. Of those species that have a state or federal designation, 46 are listed by the Florida
Committee on Rare and Endangered Plants and Animals; 53 are listed by the Florida Natural Areas
Inventory; and 26 are on the Audubon Society’s Watch List (see Appendix D for a complete listing of
these species). [Nationally, 1,262 species are federally listed with 986 listed as endangered
(including 388 animals and 598 plants) and 276 listed as threatened (including 129 animals and 147
plants). Further, 257 species are listed as candidates for federal listing.]
Comprehensive Conservation Plan 19
The refuge serves to protect, maintain, and enhance the high productivity and biological diversity
within this system. Increasing human population growth and impact have altered many ecological
characteristics of Indian River Lagoon. The refuge faces ongoing threats from contaminated air, soil,
and water; from erosion and sedimentation; and from cumulative habitat impacts from land and water
resource development activities adjacent to and on the refuge (e.g., NASA’s operations facilities).
Rapid population growth and development have resulted in long-term negative impacts to Merritt
Island National Wildlife Refuge, including increased boat traffic in the shallow waters of the lagoon,
increased use and development of natural resources in the area, local habitat fragmentation, and the
introduction and spread of exotic species.
Due to elevation, topographic relief, and proximity of the refuge to the ocean, impacts on the refuge
stemming from global warming and climate change may manifest themselves through rising sea level
and increased tropical cyclones. Rising sea level could result in wetter hydrologic regimes and
saltwater intrusion. The extent and nature of the refuge’s impoundments and marshes could be
altered. More frequent and more intense tropical cyclones could cause alteration to the beach
profiles and affect the flora and fauna that presently use these habitats.
The refuge has a history of working with its partners on the management of a wide variety of issues.
This cooperation can be extended to collect data, develop modeling, and determine possible
management activities that would relate to the effects of climate change. It is certainly true that more
scientifically valid data are needed to effectively determine what management actions might be
appropriate to combat the possible effects of global warming.
Due to the current state of knowledge about the nature and extent of global warming and climate
change impacts to the refuge, the focus will be to monitor and collect data relevant to changes in
habitats and wildlife over the life of this plan. One action the refuge can take is to incorporate more
information on possible changes brought about as a result of global warming in outreach to the
public. In addition, the refuge can work cooperatively with partners to develop prudent adaptive
management strategies that work in concert with changes brought about due to global warming.
Native terrestrial habitats that once dominated uplands include hardwood hammocks, which are very
important for mammals and migratory birds. Urbanization and agricultural operations (e.g., large
citrus groves) now dominate land uses in the upland areas along the entire Indian River Lagoon.
Historically, citrus and other agricultural operations, such as cattle pastures, dominated the area’s
landscape, but these are quickly being replaced by urban and suburban sprawl. Stormwater inputs,
saltwater exchange through fortified ocean inlets, pollution, habitat destruction, and continual land
and water use practices are constant threats to fish and wildlife resources in this area. By the year
2015, Florida is expected to have more than 20 million residents, while the four-county area around
the refuge is anticipated to reach nearly 3 million (Lenze 2002).
The reduction of ecological function and connection are major concerns, especially in areas where
the modification of inland waterways has caused declines in fisheries and aquatic resource
productivity. Beaches, seagrass beds, salt marshes, mangrove islands, and hammocks are subject
to further loss or elimination. Some known environmental modification includes the construction of
causeways (e.g., impacting seagrasses); the construction and maintenance of the Intracoastal
Waterway (e.g., changing hydrological functions and salinity); the development of beaches and
shorelines (e.g., impoundments, impacting fragile coastal habitats for migratory birds, small
mammals, and nesting sea turtles); and fishing activities (e.g., increasing recreational and
commercial uses) in transitional and aquatic communities and habitats. Causeway construction,
canal dredging, and commercial agricultural operations have contributed to the long-term loss and
20 Merritt Island National Wildlife Refuge
elimination of aquatic resources and habitats. In addition, declining water quality due to increased
sediment and nutrient runoff is likely to adversely impact seagrass communities, resulting in declines
in fish and mollusk (fisheries and aquatic resource) production.
Estuarine wetlands (native salt marsh and mangrove swamps) on the refuge were impounded to
meet mosquito control needs. Refuge wetland management objectives include reconnecting
impoundments and restoring natural-like flow and biological interchange, while maintaining mosquito
control and migratory bird habitats.
Invasive exotic plants have displaced many native species in upland and wetland communities.
Brazilian pepper and Australian pine are two invasive species that are widespread throughout the
refuge. Citrus trees for agricultural harvest cover other large areas. As adjacent urbanization and
suburbanization continue to increase, the refuge is likely to experience an increased threat from feral
animals, free-roaming pets, recreational boating, elevated nutrient loading, and pollution, as well as
from the increased demand for public use activities that are not directly linked to fish and wildlife
goals. Additionally, new recreational technologies are likely to be developed that may not be
compatible with fish and wildlife management.
Increased disturbance of fish spawning areas and nesting and roosting birds, and impacts to water
quality and habitat are likely to lower the refuge’s biological integrity. Management overlap of refuge
lands and waters is shared by multiple agencies and a continual challenge is to coordinate conservation
management with the more than 100 agencies and organizations which share the responsibility of
managing the Indian River Lagoon watershed (Indian River Lagoon National Estuary Program 1996).
The lack of Service ownership of most of the refuge presents a difficult management challenge. The
Service owns ± 925.7 acres; manages ± 320.04 acres under a lease or management agreement with
the State of Florida; and manages nearly 135,000 acres through a management agreement with
NASA (including over 4,000 acres in operational areas at Kennedy Space Center for specific
responsibilities, including removing nuisance wildlife from these areas).
State and federal assessments of the coastal zone to vulnerability from current and future sea level
rise reflect coastal changes, particularly to coastal barrier island systems. Leatherman and Kershaw
(2001) reported an approximate rate of 2 mm/year, which was estimated to accelerate over time to
20–30 cm by 2100 along the Florida Atlantic coast (Ron Schaub, Dynamac, Inc., personal
communication). The average rate of sea level rise at Mayport, Florida, is 2.43 mm/yr with a standard
error of 0.18 mm/yr based on monthly mean sea level data from 1928 to 1999 (National Oceanic and
Atmospheric Administration 2001). Impacts to the refuge could include beach and dune habitat
changes that would pose threats to several federally listed sea turtles and the southeastern beach
mouse. Loss of dune systems and lowered dune profile could increase sea turtle disorientation from
lighting at NASA’s and the U.S. Air Force’s launch facilities. The refuge’s beach has been changing
with a mix of points of accretion and erosion since the 1800s with no observed long-term trend (Ron
Schaub, Dynamac, Inc., personal communication). However, increased sea level would exacerbate
beach erosion and may reconfigure the beach and shoreline contour (e.g., the beach could
experience increased overwash and the formation of an inlet in Mosquito Lagoon). Additionally,
impacts could include inundation of low-lying areas along the Mosquito Lagoon, Indian River Lagoon,
and the Banana River, including marshes, impoundment dikes, marsh islands, and spoil islands. The
changes could include habitat transitions from upland to coastal wetlands. Saltwater intrusion into
aquifers and increased flooding potential (increasing the potential for impacts from disasters) are also
important considerations, particularly in beach areas that have been developed (Leatherman and
Kershaw 2001). Coastal wetland ecologists have suggested that the coastal marshes may be
impacted if they cannot maintain the detrital-building process and the marsh elevation due to sea
Comprehensive Conservation Plan 21
level rise (accretion deficit; Reed and Cahoon 1993). They suggest that some marsh management
practices (e. g., burning or migratory bird management) would inhibit marsh accretion in a system that
has a narrow tidal range, low sediment accretion rate, and a low tolerance for accelerated sea level
rise (Cahoon et al. 2004). The rise in sea level could effectively cause the transition of high marsh
systems to lower marshes and the migration of high marshes into the fringing upland ecotones.
Marsh expansion may have beneficial impacts; however, the increase in salt marsh may also
increase the production potential of the salt marsh mosquito.
PHYSICAL RESOURCES
The climate, geology and topography, soils, air quality, and hydrology and water quality form the
foundation of the physical environment of the refuge.
CLIMATE
General Climatic Conditions
The main factors influencing the climate at Merritt Island National Wildlife Refuge are latitude and the
proximity of large bodies of water. Generally, the climate can be described as subtropical with short,
mild winters and hot, humid summers, with no appreciable spring or fall seasons. Summer weather
patterns usually begin in April and prevail for nine months.
Temperature
Summer temperatures (measured in degrees Fahrenheit) range from the low 70s at dawn to the
upper 80s and low 90s during the afternoon. November may have some cool days, but winter
weather typically starts in December and lasts through March. Average temperatures during the
winter range from lows in the 50s to highs near 75º. Temperature extremes range from a low of 19º
to a high of 100º (Patrick Air Force Base 2004).
Atmospheric Moisture
As one would expect with the large bodies of water in and around the refuge, the relative humidity
(RH) is typically high. The mean dawn RH is between 88 and 95 percent throughout the year, while
readings in the mid-afternoon are between 55 and 67 percent. Very low RH can occur with the
passage of cold fronts in the winter. Readings in the 30 to 40 percent range are common and a RH
as low as 26 percent has been recorded. On the other end of the spectrum, an RH of 100 percent is
not uncommon with fog occurring 90 days per year on average.
Precipitation
The refuge’s average annual precipitation, as recorded at the Shuttle Landing Facility, is 49 inches
(Patrick Air Force Base 2004). Rainfall typically occurs during two time periods separated by dry
seasons. Between late May and early October, weather patterns are dominated by the effects of
the Bermuda High. This system causes southeast winds that bring moist warm air onshore, leading
to the formation of thunderstorms. These are short duration, high intensity localized storms. The
refuge averages 83 thunderstorm days per year, with 60 percent of the annual precipitation
occurring during these months.
From November to February, the weather patterns are influenced by cold continental air masses.
Rainfall during this period comes from the effects of frontal passage, with rainfalls more widespread
and less intense than in the summer. The transitional periods between these two wet seasons tend
to be dry. Although uncommon, snow does occur on the refuge. The Shuttle Landing Facility has
reported snow in both December and January, but the accumulations were less than 0.05 inches.
22 Merritt Island National Wildlife Refuge
Annual precipitation amounts can vary widely. In 1998, the annual rainfall was only 34.1 inches. The
total accumulation of rainfall for the months of April, May, and June was only 1.03 inches, as compared
to the expected amount of 10.42 inches. Conversely, in the year 2001 the refuge received a total of
61.80 inches of rain, or 12.80 inches above the average recorded for the Shuttle Landing Facility.
These fluctuations in precipitation can impact refuge management operations. In 1998, for example,
many of the refuge impoundments dried out completely. The dry conditions contributed to numerous
wildfires, one of which reached over 4,000 acres in size. On the other hand, the wet conditions in
2001 made the maintenance of nonpaved roads difficult. The frequent rains and generally wet
conditions also resulted in fewer opportunities for prescribed burning.
Lightning
Because of its importance in fire management, a major refuge management activity, lightning
deserves special mention. The National Weather Service Office in Melbourne, Florida, states that
Florida is the “lightning capital of the United States” (National Weather Service 2005). According to
National Weather Service data, more than 22,000 lightning strikes occur in Brevard County each
year. Regarding the intensity of lightning on the refuge itself, research at the Kennedy Space Center
shows that within-cloud and cloud-to-ground discharges average 2.4 per minute per storm, with a rate
of 30.6 discharges per minute recorded during a storm on July 14, 1980 (National Aeronautics and
Space Administration 1984).
Wind
Wind is another important weather condition that greatly impacts the refuge. Wind patterns change
throughout the day due to such factors as sea breezes and erratic winds around thunderstorms. High
winds, above 20 miles per hour at the 20-foot level, are common in the winter and spring months, with
occasional days with 35 to 40 mph winds. High winds are also associated with tropical systems in the
summer. Several days of light and variable winds can occur in summer months when subsiding air is
entrenched over the central Florida area. Since there is essentially no elevation change over the
entire refuge, and therefore no barriers to the flow of air masses, the influences of weather apply
equally to all portions of the refuge.
Tropical Cyclones
Tropical depressions, storms, and hurricanes can impact refuge activities and infrastructure. Large
amounts of rainfall can accompany tropical cyclones. In addition, wind and wave action can result in
major damage to important refuge habitats. In 2004, three hurricanes impacted the central Florida
area. Beach erosion destroyed sea turtle nests and damaged beach mouse habitat on the refuge.
The combination of wind and wave action resulted in several millions of dollars in damage to the
refuge’s impoundment dikes. Several refuge buildings also suffered damage. On top of all this, a
substantial amount of staff time was spent in addressing hurricane damage both on Merritt Island
National Wildlife Refuge and other refuges in Florida.
GEOLOGY AND TOPOGRAPHY
Geology
According to Schmalzer et al. (2001), Florida has a complex geologic history with repeated periods of
deposition when the Florida Plateau was submerged and with erosion during periods of lower sea
level when the land was exposed (Randazzo 1997). The Avon Park limestone formation is the oldest
deposit known to exist under Brevard County. This was deposited in the early Eocene in an open
ocean. A period of lower sea levels with resultant erosion followed. In the late Eocene, seas rose
once again and the limestone of the Ocala group formation was deposited. Following another sea
level falling and rising, the Hawthorne formation of calcareous clay, phosphoric limestone,
Comprehensive Conservation Plan 23
phosphorite, and radiolarian clay was laid down in the late Miocene. Overlying the Hawthorne
formation are unconsolidated deposits of fine sand, shells, clay, and calcareous layers of the late
Miocene or Pliocene ages. The surface strata of Merritt Island are primarily unconsolidated white-to-brown
quartz sand containing beds of coquina of Pleistocene and Recent ages.
Topography
The alternating high and low sea levels during the Pleistocene and Holocene shaped the land surface
of the refuge. The outer barrier island formed after sea levels rose when the Wisconsinan glaciers
retreated. Merritt Island itself was formed as a prograding barrier island complex. The eastern edge
of Merritt Island, where it joins Mosquito Lagoon and Banana River, forms a relic cape aligned with
False Cape. The ridge and swale topography of the island is apparently the result of successive
stages of the growth of this cape (White 1970). The ridges rise to a maximum of about 10 feet above
sea level, while trough elevations are near sea level.
The western side of the island is substantially older. Erosion has reduced old dune ridges and the
area is flatter. Elevations at the center of the island approach four feet above sea level and drop off
to around one half foot at the Indian River Lagoon shoreline.
SOILS
Relatively minor differences in elevation and internal drainage of the land have resulted in major
differences in soil types. Over twenty soil series, representing four soil orders, are found on the
refuge. Detailed maps and descriptions of these can be found in the Soil Survey of Brevard County,
Florida (Soil Survey Staff 1974). Based on soils characteristics, five general associations of soils
have been identified on the refuge, as listed below:
Paola-Pomello-Astatula Association: These are soils found on narrow ridges in the area between
the Indian River Lagoon and Banana River. They are well to excessively drained acid sands.
Internal drainage is rapid, and water tables are generally below three feet. Slopes range from
nearly level to strongly sloping. The natural vegetation is scrub oaks, palmetto, and grasses.
Canaveral-Palm Beach-Welaka Association: These soils are nearly level to gently sloping sands
that are well to excessively drained. They are found on narrow ridges and sloughs parallel to the
Atlantic Ocean. Natural vegetation is scrub oaks, cactus, palmetto, and some pine.
Myakka-Eau Gallie-Immokalee Association: These associations are nearly level, poorly drained,
acid soils. They are sandy to a depth of 40 inches and loamy below. They are found on
flatwoods sites between the ridges. Water tables are usually within 30 inches of the surface, and
there may be standing water on these sites for short periods of time after heavy rainfall. The
natural vegetation is palmetto and pines.
Copeland-Wabasso Association: These soils are nearly level and poorly or very poorly drained.
The pH of these areas is higher than that of most flatwoods soils due to the presence of limestone
or coquina. Natural vegetation is palm, mesic hardwoods, and pine.
Salt Water Marsh-Salt Water Swamp Association: These associations are nearly level, very poorly
drained saline to brackish soils of variable texture. The marsh soils are shallow sands covered with
marl or limestone, irregularly stratified mixed sand and shell, or silty clays over sand and shell. The
natural vegetation is that of the salt marsh community. Swamp soils consist of mixed sand and
organic matter. Natural vegetation includes salt-tolerant trees, such as mangroves.
24 Merritt Island National Wildlife Refuge
AIR QUALITY
The air pollutants of major concern in Florida are carbon monoxide, lead, nitrogen dioxide, ozone,
particulate matter, and sulfur dioxide (Florida Department of Environmental Protection 1999). The
primary sources of these pollutants are vehicle emissions, power plants, and industrial activities. In
1999, all areas of Florida were air quality attainment areas (Florida Department of Environmental
Protection 1999). The Indian River Lagoon area is considered to have good air quality. However,
occasional temperature inversions, lasting up to 48 hours, can temporarily degrade local air quality
below acceptable levels
Kennedy Space Center and, therefore, the Merritt Island National Wildlife Refuge, are considered an
attainment or clean area under the Clean Air Act. The ambient air quality is influenced by NASA
operations; land management practices, such as prescribed burning; vehicle traffic; and offsite
emission sources. The daily air quality conditions are most influenced by the considerable onsite
vehicle traffic, utilities fuels combustion (two regional power plants are within 10 miles of the refuge),
NASA's refurbishment and maintenance operations, and incinerator operations. Space launches,
training fires by the Kennedy Space Center Fire Department, prescribed burning, and wildfires on the
refuge influence air quality as episodic events. Smoke from wildland fires can disrupt space center
operations, such as launches, landings, and payload preparation.
The ambient air quality at Kennedy Space Center and the refuge is monitored by one Permanent Air
Monitoring System, located at NASA's Environmental Health Facility. This station is equipped with
analyzers for sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), ozone (O3), and
total inhalable particulates (10-micron).
HYDROLOGY AND WATER QUALITY
Surface Water Hydrology
The primary surface waters on and around the refuge is the Indian River Lagoon system, which has
been designated as an Estuary of National Significance. The lagoon system includes the Indian
River Lagoon, Banana River, Mosquito Lagoon, and Banana Creek. These bodies of water drain
approximately 838 square miles of land. They can best be described as shallow estuarine lagoons
with water depths of less than five feet, with the exception of the Intracoastal Waterway which, with a
project depth of 12 feet, is the deepest part of the entire system. The Banana River is directly
connected to the Atlantic Ocean by an artificial inlet and locks at Port Canaveral. The Indian River
Lagoon is indirectly connected to the Atlantic Ocean on the north by Haulover Canal, Mosquito
Lagoon, and the Ponce de Leon Inlet, and on the south by Sebastian Inlet. Water circulation within
the lagoons are not affected by tides, but instead are affected by the Intracoastal Waterway (e.g.,
navigation channel maintenance and boat usage), winds, inlets, and causeways.
In addition to the lagoon system, numerous creeks, mosquito control impoundments, borrow ponds,
and miscellaneous wetlands exist on the refuge. By the 1960s, many of the marshes were
impounded to control the production of the salt marsh mosquito (Aedes spp.). These impoundments
contain about 7,660 acres of open water and 15,500 acres of wetlands. In addition, the refuge has
more than 900 acres of borrow ponds, 5,900 acres of grassy swales, and numerous canals.
Surface Water Quality
The quality of the refuge’s surface waters is generally good, with the best areas being those adjacent
to undeveloped land. These would include both the Mosquito Lagoon and the northern portion of the
Indian River Lagoon, which have been designated as Class II waters by the State of Florida. The rest
of the lagoon system has been designated as Class III waters. All of the surface waters within the
Comprehensive Conservation Plan 25
boundaries of the refuge have been designated as Outstanding Florida Waters. All of these
designations place restrictions on the use of the surface waters. The Indian River Lagoon does have
several identified water quality parameters of concern: cadmium, lead, mercury, nutrients, selenium,
thallium, and dissolved oxygen (U.S. Environmental Protection Agency 2000). Monitoring of water
quality is conducted by both the Kennedy Space Center and the refuge.
Ground Water Hydrology
Ground water of the refuge occurs under both nonartesian (unconfined) and artesian (confined)
conditions. The surficial (nonartesian) aquifer supports the freshwater wetlands and provides
groundwater discharge to the surrounding lagoons (Clark 1987). This aquifer occurs in saturated
Pleistocene and Holocene deposits of sand, shell coquina, silt, and marl. The upper boundary is the
water table, while the lower limit is the confining layer at the base of the Pleistocene and Holocene
deposits. The surficial aquifer is recharged by direct infiltration from local rainfall. The high sand
ridges in the center of the refuge, which are composed of permeable sands, are especially important
for recharge of the surficial aquifer
The surficial aquifer can be divided into several subsystems. The first of these is the Dune or Barrier
Island subsystem, which has a lens of freshwater three meters or less thick on top of intruded salt
water. The primary dune acts as the principal recharge area. The second subsystem is the Dune-
Swale subsystem, which runs north to south in the center of the refuge. Most of it is east of Kennedy
Parkway (State Route 3) and includes high ridges that serve as recharge areas. The pine flatwoods
and swale soils in this area have pronounced humic hardpans (spodic or Bh horizons) that restrict
infiltration. Water perches above this layer and will only infiltrate slowly. The West Plain subsystem
is the third division and is located in the flatwoods and hammock areas west of Kennedy Parkway.
Spodic horizons limit infiltration in much of the area north of Banana Creek. South of Banana Creek,
a limestone hardpan is the limiting factor. The fourth division of the surficial aquifer, the Marsh
subsystem, is found under the impoundments.
The artesian aquifers found under the refuge include the Floridian aquifer. This aquifer is associated
with Eocene limestones and is artesian. Secondary artesian aquifers occur within the Hawthorne
formation and in the Caloosahatchee Marl Equivalent.
Ground Water Quality
Ground water can be contaminated from either point sources or nonpoint sources. Merritt Island
National Wildlife Refuge/Kennedy Space Center has been used since the 1960s as the Nation’s
primary launch site for space exploration. Many hazardous chemicals have been used to support
space operations over the years, and, especially in the early years, less than adequate care had been
taken in the handling and disposal of these chemicals. Point source pollution has been documented on
the refuge/Kennedy Space Center in several instances. Contaminated areas have been found in and
around launch pads A and B, landfill sites, and sewage treatment plants, as well as at some abandoned
processing sites. The locating and meditating of contaminated sites is an ongoing process, the majority
of which is handled by NASA. The refuge has been involved on a limited basis in detecting possible
point sources in the citrus grove areas where chemicals have been stored.
The citrus grove operations also have the potential for nonpoint source pollution. The application of
fertilizer, insecticides, and other chemicals during grove caretaking operations falls under the area of
nonpoint source pollutants. The refuge is cooperating with the Florida Research Center for
Sustainable Agriculture in a study to determine the impacts of various citrus management practices
on the environment, including on ground and surface waters (Adair 2003).
26 Merritt Island National Wildlife Refuge
The areas of the refuge subject to known point source pollution and agricultural activities are
relatively small. A recent study of the surficial aquifer on the refuge found that contamination in large
areas of the refuge was low (Schmalzer and Hensley (2001). This investigation looked at a number
of possible pollutants. Organochlorine pesticides, aroclors, and chlorinated herbicides were below
detection levels. Seven polycyclic aromatic hydrocarbons occurred at low concentrations in some
areas. These hydrocarbons can have both natural and human activity sources. Most trace elements
were below detection levels or were found in low concentrations. They concluded that widespread
contamination of the surficial aquifer on the refuge has not occurred.
BIOLOGICAL RESOURCES
The habitats on the refuge and their condition are the end result of both the physical environment and
past anthropological activities. The climate, soils, and hydrology have determined which plant and
animal species can exist here. Humans have then exerted their influences on the biota.
The influence of human activity on the landscape has been going on for a considerable time. Native
Americans probably did little to modify the physical landscape, but may have modified ecological
processes through their use of fire. The numerous thunderstorms that occur during the summer
months frequently ignited wide-ranging wildland fires (Duncan et al. 1999). Many of the vegetation
types found on the refuge are dependent on periodic fires for their continued existence. Native
Americans used fire outside of this time period for various purposes, such as hunting and warfare
(Robbins and Myers 1992).
When European settlers arrived, they also varied the natural fire regime. They also began to modify
the physical landscape, starting with the construction of roads, drainage ditches, and canals. The
use of the land for agriculture increased the construction of infrastructure, but major alterations to the
landscape did not occur until the 1950s. During the next several decades, fire was excluded from the
landscape. The vegetation on the land which is now the refuge became overgrown, reducing its
utility for some native wildlife.
During this time, other important changes occurred. Some of the land was converted to agriculture,
where most of it became citrus groves. In the early 1960s, fragmentation of the land increased as the
infrastructure for the John F. Kennedy Space Center was constructed. To help control mosquitoes,
many of the marshes were impounded.
Since the refuge was founded, much management has been done. Some management activities
were directed towards restoring portions of the landscape to more natural conditions. Other activities
maintained or modified the existing structures, such as the impoundments, to increase their value to
wildlife. The mix of upland, wetland, and aquatic habitats that are the end result of the various natural
and anthropologic phenomena are described. Figure 6 shows the refuge’s existing impoundment
management units and Figure 7 the refuge’s burn units.
HABITAT
Schmalzer et al. (2002) lists 1,024 species of plants on the refuge. Of these, 803 are native and 221
are introduced. These plants are organized into vegetative communities. A habitat/vegetation map
delineating these communities has been developed for the area inside the acquisition boundary of
Merritt Island National Wildlife Refuge (Figure 8). Vegetation was classified using the terminology of
the National Vegetation Classification System. In this classification system, the floristic association is
the most applicable level to refer to when managing the vegetation on the refuge. However, the
terminology of the classification system is seldom used by on-the-ground practitioners. Therefore,
Comprehensive Conservation Plan 27
Figure 6. Impoundment Management Units
28 Merritt Island National Wildlife Refuge
Figure 7. Burn units
Comprehensive Conservation Plan 29
Figure 8. Refuge vegetation
30 Merritt Island National Wildlife Refuge
the cover types shown on the map are the colloquial names that have been used in the local area for
many years. Table 1 provides the mandated classification system terminology for the alliance and
association levels, along with a colloquial name for the various habitat types found on the refuge.
The complete table, giving the entire classification system hierarchy, is in the refuge’s administrative
files. A detailed description of the individual habitat types can also be found in the refuge’s Habitat
Management Plan (see Appendix F).
Wetland Herbaceous Communities
Marsh – saltwater (Salt marsh, impounded or otherwise); (SPARTINA BAKERII – DISTICHLIS
SPICATA TIDAL HERBACEOUS ALLIANCE, Spartina bakerii – Distichlis spicata Association)
Most of the salt marshes at the refuge were impounded for mosquito control in the 1950s and 1960s.
As a result, waters within the impounded salt marshes tend, on average, to have lower salinities
(depending on current impoundment management and precipitation) than would otherwise be
expected in unmodified salt marsh habitats. Despite this, most impoundments currently retain
vegetation associations that could still be described as salt marsh. The salt marshes of the refuge
(both impounded and un-impounded) are dominated by Baker’s cordgrass (Spartina bakerii) and salt
grass (Distichlis spicata). Other salt tolerant plants frequently encountered within the salt marshes
include black needle rush (Juncus roemerianus), glassworts (Salicornia spp.), and saltwort (Batis
maritima). In some impounded salt marshes, other, less salt tolerant plant species may also be
found, including cattail (Typha spp.) and sawgrass (Cladium jamaicense).
Wetland Shrub - saltwater; (BORRICHIA FRUTESCENS TIDAL SHRUBLAND ALLIANCE)
This alliance includes areas within both impounded and un-impounded salt marsh that, in addition to
Baker’s cordgrass, contain shrub species, including sea oxeye (Borrichia frutescens); wax myrtle (Myrica
cerifera); scattered mangroves; and the invasive, exotic Brazilian pepper (Schinus terebinthifolius). These
shrub areas often occur above mean high water and are typically adjacent to landward areas.
Marsh – freshwater; (SPARTINA BAKERII SEASONALLY FLOODED HERBACEOUS ALLIANCE,
Spartina bakerii Association)
Freshwater marshes typically occupy interdunal swale areas and are seasonally flooded (although
deeper marshes may stay flooded in all but the driest years). These marshes are dominated by
Baker’s cordgrass, but may also contain beardgrass (Andropogon spp.) and sawgrass (Cladium
jamaicence). In the absence of fire, these wetlands are often encroached by woody species such as
willow, wax myrtle, and red maple.
Wetland Shrublands
Mangrove; (AVICENNIA GERMINANS-LANGUNCULARIA RACEMOSA-RHIZOPHORA
MANGLE TIDAL SHRUBLAND ALLIANCE, Avicennia germinans-Languncularia racemosa-
Rhizophora mangle Association)
Mangroves are found along the fringes of the marine waters and in some impoundments. The major
species here are black mangrove (Avicennia germinans), white mangrove (Languncularia racemosa),
red mangrove (Rhizophora mangle), and buttonwood (Conocarpus erecta). Mangroves trap and
collect sediment to help stabilize shorelines and reduce flood damage. More than 100 species of fish
and shellfish are dependent on mangroves. Key animal species found in this habitat include
mangrove water snakes, river otters, raccoons, snook, pelicans, wood storks, herons, egrets,
shorebirds, periwinkle snails, and juvenile and predatory fish.
Comprehensive Conservation Plan 31
Table 1. Vegetation and cover types on Merritt Island National Wildlife Refuge
Cover Type and
(Colloquial
terminology
from Vegetation Map
& HMP Text)
Floristic Alliance
(NVCS)
Floristic Association
(NVCS) Acres
Infrastructure - primary N/A N/A 1390.36
Infrastructure -
secondary
N/A N/A
726.91
Rural - residential N/A N/A 46.24
Total Nonhabitat Acres 2163.51
Estuary N/A N/A 53069.68
Barren land - may be
inundated
N/A N/A
260.76
Water - interior - salt
(Open water in
impoundments)
N/A N/A
7660.05
Marsh - saltwater
(Salt marsh,
impounded or
otherwise)
SPARTINA BAKERII-DISTICHLIS
SPICATA
tidal herbaceous alliance
Spartina bakerii-Distichlis
spicata Association
13635.37
Wetland shrub-scrub -
saltwater
BORRICHIA
FRUTESCENS shrubland
alliance
N/A
1893.92
Mangrove AVICENNIA GERMINANS-LANGUNCULARIA
RACEMOSA-RHIZOPHORA
MANGLE
tidal shrubland alliance
Avicennia germinans-
Languncularia racemosa-
Rhizophora mangle
Association
1659.84
Total Saline Wetland Acres 78179.62
Ditch N/A N/A 375.36
Water - interior - fresh
(Borrow Pond)
N/A N/A
960.73
Marsh - freshwater
(Swale)
SPARTINA BAKERII
seasonally flooded
herbaceous alliance
Spartina bakerii
Association
5912.51
Wetland shrub-scrub -
freshwater (Willow)
SALIX CAROLINIANA
temporarily flooded
shrubland alliance
Salix caroliniana
Association
5488.89
32 Merritt Island National Wildlife Refuge
Cover Type and
(Colloquial
terminology
from Vegetation Map
& HMP Text)
Floristic Alliance
(NVCS)
Floristic Association
(NVCS) Acres
Total Freshwater Wetlands 12737.49
Beach N/A N/A 65.98
Coastal strand SERENOA REPENS-COCCOLOBA
UVIFERA
shrubland alliance
Serenoa repens-Coccoloba
uvifera Association
718.02
Total Beach and Dune 784.00
Oak scrub
(also scrubby
flatwoods)
QUERCUS GEMINATA-QUERCUS
MYRTIFOLOIA-SERENOA
REPENS shrubland
alliance
Quercus geminata-Quercus
myrtifolia-Serenoa repens
Association
15344.24
Palmetto scrub SERENOA REPENS-ILEX
GLABRA-LYONIA SPP.
shrubland alliance
Serenoa repens-Ilex
glabra-Lyonia spp.
Association 3142.76
Planted oak scrub QUERCUS GEMINATA-QUERCUS
MYRTIFOLIA-SERENOA
REPENS
shrubland alliance
Quercus geminata-Quercus
myrtifolia-Serenoa repens
Association
24.81
Total Upland Shrubland
18511.81
Wetland hardwood
forest
ACER RUBRUM-ULMUS
AMERICANA seasonally
flooded forest alliance
Acer rubrum-Ulmus
americana Association
1185.64
Wetland
coniferous/hardwood
forest
PINUS ELLIOTTII-QUERCUS
VIRGINIANA
saturated temperate forest
alliance
Pinus elliottii-Quercus
virginiana Association
1603.24
Total Wetland Forest 2788.88
Cabbage palm
(Palm Hammock)
SABAL PALMETTO
temperate forest alliance
Sabal palmetto Association
2880.61
Hardwood Hammock QUERCUS VIRGINIANA-SABAL
PALMETTO forest
alliance
Quercus virginiana-Sabal
palmetto Association
9569.24
Upland hardwood
forest
QUERCUS VIRGINIANA-SABAL
PALMETTO forest
alliance
Quercus virginiana-Sabal
palmetto Association
594.57
Comprehensive Conservation Plan 33
Cover Type and
(Colloquial
terminology
from Vegetation Map
& HMP Text)
Floristic Alliance
(NVCS)
Floristic Association
(NVCS) Acres
Planted hardwoods QUERCUS VIRGINIANA-QUERCUS
LAURIFOLIA
forest alliance
Quercus virginiana-
Quercus laurifolia
Association 285.41
Pine flatwoods PINUS ELLIOTTII-SERENOA
REPENS
alliance
Pinus elliottii-Serenoa
repens Association
2999.18
Upland
coniferous/hardwood
forest
PINUS ELLIOTTII-QUERCUS
VIRGINIANA
saturated temperate forest
alliance
Pinus elliottii-Quercus
virginiana Association
2730.07
Upland coniferous
forest
PINUS ELLIOTTII-SERENOA
REPENS
alliance
Pinus elliottii-Serenoa
repens Association
274.53
Planted pine PINUS ELLIOTTII tropical
forest alliance
Pinus elliottii var. densa
Association 203.98
Total Mesic and Upland Forest 19537.59
Ruderal - herbaceous
(Lawns, disturbed
areas)
No floristic dominance N/A
3745.96
Australian pine CASUARINA SPP. Forest
alliance
Casuarina spp. Association
111.71
Ruderal - woody*
(Brazilian pepper)
SCHINUS
TEREBINTHIFOLIUS-MYRICA
CERIFERA
shrubland alliance
Schinus terebinthifolius-
Myrica cerifera Association
1540.83
Citrus CITRUS SPP. Woodland
alliance
Citrus spp. Association
1930.92
Total Nonnative Vegetation* 7329.42
TOTAL MINWR ACRES 142032.32
*Although some areas are dominated by nonnative vegetation as the primary vegetation cover type,
as detailed in the table, all refuge habitats are likely to have the presence of nonnative vegetation.
34 Merritt Island National Wildlife Refuge
Willow Swamp; (SALIX CAROLINIANA TEMPORARILY FLOODED SHRUBLAND ALLIANCE, Salix
caroliniana Association)
Willow stands also have standing water on them for most of the year. They are dominated by
Carolina willow (Salix caroliniana) with some red maple and wax myrtle. In many cases, willows have
invaded upland swales and impoundments.
Wetland Hardwood Forests and Woodlands
Wetland Hardwood Forest; (ACER RUBRUM-ULMUS AMERICANA SEASONALLY FLOODED
FOREST ALLIANCE); Acer rubrum - Ulmus americana Association)
The hardwood swamp areas have standing water for large portions of the year. They are dominated
by red maple (Acer rubrum) and elm (Ulmus americana), but may have cabbage palm and water
tolerant oaks. Some of these areas were once grassy swales that have changed over time as the
result of alterations in hydrology and/or from the exclusion of fire.
Cabbage Palm Hammock; (SABAL PALMETTO TEMPERATE FOREST ALLIANCE; Sabal palmetto
Association)
These hammocks are almost pure stands of cabbage palms (Sabal palmetto). The understory is
usually open with a scattering of palmetto and other vegetation. Although cabbage palms can grow
on soils with a wide range of moisture regimes, they are typically found on more or less saturated
soils, such as those along the edges of impoundments. As the soils become better drained, the
vegetation grades into the mesic oak/palm hammocks.
Cabbage palm hammocks can also be found on disturbed sites. Land that was once cleared for
home sites or for agriculture often times comes back as stands of exotics and cabbage palms when
abandoned. This situation is especially noticeable in the case of citrus groves that have gone fallow.
Mesic Hardwood Forests and Woodlands
Hardwood Hammock; (QUERCUS VIRGINIANA-SABAL PALMETTO FOREST ALLIANCE; Quercus
virginiana-Sabal palmetto Association)
These hammocks are dominated by large live oaks (Quercus virginiana), cabbage palms, and laurel
oaks (Q. laurifolia). The understory in some of these hammocks is palmetto (Sabal palmetto), while
others have a mix of subtropical shrubs, such as wild coffee (Psychotria spp.), nakedwood
(Myrcianthes fragrans), Ardisia spp., and ferns, along with the palmetto.
Upland Hardwood Forest; (QUERCUS VIRGINIANA-SABAL PALMETTO FOREST ALLIANCE;
Quercus virginiana-Sabal palmetto Association)
Although classified the same as the hardwood hammocks, the upland hardwood forests occupy
slightly better drained soils. These are mixed hammocks that have not only cabbage palms and live
and laurel oaks, but also elms, ashes (Fraxinus spp.), red mulberries (Morus rubra), sugar berries
(Celtis laevigata), and other overstory species. The understories may have nakedwood, wild coffee,
and southern red cedar (Juniperus virginiana var. siliciola).
Oak-Cedar Hammocks; (QUERCUS VIRGINIANA-SABAL PALMETTO FOREST ALLIANCE;
Quercus virginiana-Sabal palmetto-Juniperus virginiana var. siliciola Association)
These stands are similar to the upland hardwood hammocks, but have a substantial amount of
southern red cedar in them. The majority of these stands are found in the Turnbull Creek area.
Comprehensive Conservation Plan 35
Planted Hardwoods; (QUERCUS VIRGINIANA-QUERCUS LAURIFOLIA FOREST ALLIANCE;
Quercus virginiana-Quercus laurifolia Association)
These stands were planted on old citrus groves in the northern portion of the refuge during 1991 and
1992. The original planting density was six feet within row spacing with 12 feet between rows. By
2004 the crowns have closed within the rows. The understory consists mainly of exotic grasses left
over from the citrus operation.
Xeric Hardwood Forest
Xeric Hammock; (QUERCUS GEMINATA-QUERCUS MYRTIFOLIA ALLIANCE; Quercus geminata-
Quercus myrtifolia Association)
This type is found on the Paola-Pomello-Astatula soil association, which is deep, well to excessively
drained soils. The overstory vegetation is sand live oak (Quercus geminata), myrtle oak (Q.
myrtifolia), and Chapman’s oak (Q. chapmanii). This vegetation type is often the end result of long
periods of fire exclusion. The vegetation has become a dense, almost impenetrable stand reaching
heights of 30 or more feet. The understory is sparse, consisting of clumps of palmetto. There is little
in the way of an herbaceous layer. Much of this vegetation type has been restored to oak scrub.
Most remaining stands are too small in area to warrant mapping.
Pine Forests and Woodlands
Pine Flatwoods; (PINUS ELLIOTTI-SERENOA REPENS ALLIANCE; Pinus elliotti-Serenoa repens
Association)
The pine flatwoods forests and woodlands are generally found on the poorly drained spodosols of the
Myakka-Eau Gallie-Immokalee soil association. The overstory consists of two species of pines.
South Florida slash pine (Pinus elliottii var. densa) makes up the vast majority of the pine population.
Pond pine (P. serotina) can be found in small stands on very wet areas. Pine stands range widely in
stocking densities, age, and height. The understory of the pine flatwoods varies depending on the
elevation of the site. Common to all flatwoods sites is saw palmetto. Additional understory species
on the mesic sites can include wax myrtle (Myrica cerifera), gallberry (Ilex glabra), and Lyonia spp.
As the soils become dryer with increased elevation, the gallberry and wax myrtle become fewer and
sand live oak, myrtle oak, and Chapman’s oak begin to appear. The higher flatwoods, with a high
proportion of scrub oaks, are locally known as scrubby flatwoods. The pine flatwoods forests are of
special interest because they provide nesting habitat for the bald eagle (Haliaeetus leucocephalus).
Where the pine overstory is sparse, the scrubby flatwoods can provide habitat for the Florida scrub-jay
(Aphelocoma coerulescens).
Upland Coniferous Forests; (PINUS ELLIOTTII-SERENOA REPENS ALLIANCE; Pinus elliottii-
Serenoa repens Association)
The upland coniferous forest and woodlands occur on both the Myakka-Eau Gallie-Immokalee and
the Canaveral-Palm Beach-Welaka soil associations. South Florida slash pine is the predominant
tree species, but small patches of sand pine (Pinus clausa) are also found. Many of the sites
occupied by these stands have been disturbed in the past. The understory has many of the same
species as is found in the flatwoods, including palmetto and Lyonia. Shrub species favoring drier
soils are also found, including sand live oak, myrtle oak, and Chapman’s oak. On the disturbed sites
the understory shrub layer may be absent or scattered. These areas may also contain a number of
exotic grasses and forbs.
36 Merritt Island National Wildlife Refuge
Planted Pine; (PINUS ELLIOTTII TROPICAL FOREST ALLIANCE; Pinus elliottii var. densa Association)
Abandoned citrus groves were planted to south Florida slash pine in the late 1980s and early
1990s. These have developed into uniform stands. The understory consists of exotic grasses
left over from citrus operations.
Mixed Pine Hardwood Forests
Wetland Coniferous/Hardwood Forests; (PINUS ELLIOTTII-QUERCUS VIRGINIANA SATURATED
TEMPERATE FOREST ALLIANCE; Pinus elliottii-Quercus virginiana Association)
These stands can be found on the Copeland-Wabasso soil association. The overstory is
predominately live oak, south Florida slash pine with some cabbage palms. There may be some red
maple and other wetland species in the midstory. The understory can have palmetto, wax myrtle, and
other moist-soil species.
Upland Coniferous/Hardwood Forests; (PINUS ELLIOTTII-QUERCUS VIRGINIANA FOREST
ALLIANCE; Pinus elliottii-Quercus spp. Association)
These stands can be found on the Copeland-Wabasso soil association, but at a slightly higher
elevation. South Florida slash pine and live oak are the predominant overstory species. There may
be other mesic hardwoods in the canopy, such as elms, ashes, red mulberries, and sugar berries.
Shrubland Communities
Oak Scrub and Scrubby Flatwoods; (QUERCUS GEMINATA-QUERCUS MYRTIFOLIA-SERENOA
REPENS SHRUBLAND ALLIANCE; Quercus geminata -Quercus myrtifolia-Serenoa repens Association)
This community is found on the well-drained soils of the Paola-Pomello-Astatula soil association, which
are located on the higher ridges of the refuge. The vegetation consists of palmetto (Serenoa repens),
sand live oak (Quercus geminata), myrtle oak (Q. myrtifolia), and Chapman’s oak (Q. chapmanii). As the
elevation decreases towards palmetto, flatwoods, or swales, more mesic vegetation can be found. The
species mix here would include gallberry (Ilex glabra) and various Lyonia species. This lower elevation
species complex is also known as the scrubby flatwoods. Pines can be associated with both the true oak
scrub and the scrubby flatwoods. Sand pine (Pinus clausa) is present on the dryer sites, while south
Florida slash pine (P. elliottii var. densa) is found in the scrubby flatwoods.
Fire is essential in maintaining both the vertical and horizontal structure of the oak scrub and scrubby
flatwoods. Historically, fires ranged through oak scrub areas, keeping the oaks short. The stands were
open in nature with numerous sandy openings. Pine stands, although always an important component of
the landscape, were scattered and sparse. In the absence of fire during the 1960s and 1970s, the oaks
and palmettos became tall dense thickets with no open areas. Pine stocking increased dramatically in
some areas, effectively changing the landscape from shrubland to forest. Many of these overgrown oak
scrub areas have been cut and burned over the past 15 years in an attempt to create a more natural
landscape. In addition, pines densities have been reduced through commercial harvesting, burning, and
using mechanical treatment. Although much success has resulted in recreating the vertical structure of
oak scrub, persistent openings remain lacking in many areas.
Palmetto Scrub; (SERENOA REPENS-ILEX GLABRA-LYONIA SPP. SHRUBLAND ALLIANCE;
Serenoa repens-Ilex glabra-Lyonia spp. Association)
The palmetto scrub occurs on the soils of the Myakka-Eau Gallie-Immokalee soil association. The
majority of the vegetation is palmetto, gallberry, wax myrtle (Myrica cerifera), and several species of
Lyonia. In many instances, this type is found in close association with the oak scrub. There is no real
definitive break between these two types, but rather a gradual progression from one to the other. As
the elevation on the land rises, scrub oaks can be found mixed in with the palmetto scrub vegetation.
Comprehensive Conservation Plan 37
Planted Oak Scrub; (QUERCUS GEMINATA-QUERCUS MYRTIFOLIA-SERENOA REPENS
SHRUBLAND ALLIANCE; Quercus geminata -Quercus myrtifolia-Serenoa repens Association)
An attempt to restore a 10-acre abandoned citrus grove near WSEG Road was conducted in
1992. Prior to planting, old citrus trees were removed and an attempt was made to control
exotic grasses on the site. Sand live oak, myrtle oak, and Chapman oak were planted at a
stocking rate of 400 stems per acre in August 1992. Additional oaks were planted in 1993
along with palmetto, rusty lyonia (Lyonia fruticosa), shiny blueberry (Vaccinium myrsinites),
and south Florida slash pine. This effort was marginally successful (Schmalzer et al. 2002).
Coastal Strand; (SERENOA REPENS-COCCOLOBA UVIFERA SHRUBLAND ALLIANCE,
Serenoa repens-Coccoloba uvifera Association)
Coastal strand is found in a narrow band immediately inland from the beach. Salt spray and poor,
sandy soils are the limiting factors. The most common plants found here are saw palmetto (Serenoa
repens), sea grape (Coccoloba uvifera), snowberry (Chiococca alba), sea oats (Uniola paniculata),
beach grass (Panacium amarum), and wax myrtle (Myrica cerifera). Vegetation seldom reaches a
height of over four feet and shows marked evidence of hedging from salt spray.
Nonnative Plant Communities
Citrus Groves; (CITRUS SPP. WOODLAND ALLIANCE; Citrus spp. Association)
Various species of citrus were planted prior to the acquisition of the lands of the refuge by the
government for Kennedy Space Center. Some of these have been allowed to go fallow, while others
are being managed by the Florida Research Center for Sustainable Agriculture in an effort to develop
more environmentally friendly citrus culture methods.
Brazilian Pepper; (SCHINUS TEREBINTHIFOLIUS-MYRICA CERIFERA SHRUBLAND ALLIANCE,
Schinus terebinthifolius-Myrica cerifera Association)
Many disturbed areas, including dikes and abandoned facilities, have been invaded by Brazilian
pepper and other exotics, along with native species, such as wax myrtle. These stands are thick,
almost impenetrable thickets. There is little in the way of ground vegetation.
Australian Pine; (CASUARINA SPP. FOREST ALLIANCE, Casuarina spp. Association)
Australian pine was planted around citrus groves and home sites as wind breaks. These are dense
stands of Casuarina with little, if any, understory. The ground cover is almost exclusively needles and
other debris from the trees.
WILDLIFE
Merritt Island National Wildlife Refuge supports a high diversity of fish and wildlife. This high
biodiversity is, in part, the result of the refuge’s location on the Indian River Lagoon, which is often
touted as having the greatest biodiversity of any estuary in North America. However, the
undeveloped nature of the refuge’s landscape and diversity of habitats also contributes to the high
biodiversity. The refuge’s estuarine waters support a wide variety of resident and migratory birds,
mammals, reptiles and amphibians, fish, and invertebrates. The estuary also provides important
habitat to marine mammals (including Atlantic bottlenose dolphins and West Indian manatees) and
marine reptiles (including juvenile green sea turtles). Upland and freshwater wetland areas provide
additional habitats to support a variety of species.
38 Merritt Island National Wildlife Refuge
The refuge serves as a key area for biodiversity, with a species richness that is very important to the
overall ecological integrity and health of the Indian River Lagoon and the North Florida Ecosystem.
The Service manages refuge resources and coordinates with neighboring land managers and
agencies to conserve biological diversity.
The refuge also serves as an important site for the recovery of federal- and state-listed threatened
and endangered species. The refuge’s location and habitat features provide protection and
management opportunities for the future of 10 federally listed threatened and endangered species
that regularly occur on the refuge, as well as for the future of three additional wildlife species listed by
the State of Florida as threatened or endangered (Epstein and Blihovde 2006). The 10 federally
listed wildlife species that regularly occur on the refuge are the West Indian manatee; southeastern
beach mouse; Florida scrub-jay; bald eagle; wood stork; piping plover; eastern indigo snake; and
loggerhead, green, and leatherback sea turtles. Of the total listed animal species in the refuge’s
records, 17 are federally listed. However, seven of these species (the American alligator, Kemp’s
ridley sea turtle, Hawksbill sea turtle, Atlantic salt marsh snake, snail kite, Audubon’s crested
caracara, and roseate tern) either have a special listing (i.e., alligator) or have rarely or never been
recorded on the refuge (i.e., Atlantic salt marsh snake). This brings the actual number of state or
federally listed species that regularly occur on the refuge to 41, of which 10 are federally listed and 31
are state-listed species (which excludes the alligator and includes 28 plant species). Additional
information on the refuge’s listed and designated species is provided in Appendix D.
Birds
Avian species are a highly important refuge resource. To date, more than 300 species of birds (both
resident and transient) have been identified using the refuge for nesting, roosting, feeding, or loafing.
This includes seven species that are federally listed as threatened or endangered (Audubon’s crested
caracara, bald eagle, Florida scrub-jay, piping plover, roseate tern, snail kite, and wood stork); 42
species federally listed as Birds of Conservation Concern; 11 species listed by the State of Florida as
threatened or endangered; and 12 species listed by the State of Florida as Species of Special
Concern (see Appendix D for a listing of these birds.) Of the seven species federally listed as
threatened or endangered, four regularly depend on the habitat provided by the refuge: the Florida
scrub-jay, bald eagle, piping plover, and wood stork. In addition to serving as important habitat for
threatened and endangered species, the refuge supports a wide variety of other resident and
migratory birds. Waterfowl, wading birds, shorebirds, and neotropical migratory birds (i.e., songbirds
or passerines) all depend on the diverse habitats offered by the refuge.
Florida Scrub-jay
The federally threatened Florida scrub-jay (Aphelocoma coerulescens) is one of the most intensively
managed species on the refuge. Although there is some uncertainty concerning the specific numbers
(Johnson et al. 2006), it is believed that the refuge is the site of the second largest population (about
550 family groups) of scrub-jays in Florida and in the world (Ocala National Forest in the northern part
of central Florida is the number one site). Areas occupied by Florida scrub-jays are characterized as
a mosaic of oak scrub, oak/palmetto, and coastal scrub habitats, as well as ruderal and disturbed
areas in the coastal regions of Merritt Island and Cape Canaveral. Many of these areas include
patches of remnant scrub in a human-altered landscape. Population size of the Florida scrub-jay is
influenced by the amount of available habitat and habitat suitability. Prescribed fire management is a
major tool in scrub habitat management.
Comprehensive Conservation Plan 39
Bald Eagle
The refuge currently supports an annual average of 11 to 13 breeding pairs of the federally
threatened southern bald eagle (Haliaeetus leucocephalus). The eagles are known to use various
pine flatwood habitats within the refuge and have used mature live pine, pine snags, and abandoned
radio towers for nest sites. Bald eagles have been shown to nest within the vicinity of large water
bodies, particularly with abundant access to fish and migratory waterfowl. The refuge’s wetland and
estuarine complex provides a diversity of excellent foraging habitats.
Piping Plover
The federally threatened piping plover (Charadrius melodus) uses coastal areas of the refuge during
spring and fall migration. Small numbers of wintering piping plovers are known to use coastal areas
north and south of the refuge. Although piping plovers do not presently winter on the refuge, they are
known to use the refuge beach during fall migration. Currently no habitat on the refuge is being
managed specifically for piping plovers.
Wood Stork
The federally endangered wood stork (Mycteria americana) is of special interest to the Service.
Wood stork populations have declined sharply in Florida, from 60,000 in the 1930s to 5,000 pairs
today, with the complete loss of wood stork nesting on the refuge. Wood storks were first breeding in
the refuge’s Moore Creek colony in 1972 (with 35 nests). Nest numbers peaked in 1980 (with 350
nests) and varied in number until 1986. A severe freeze occurred in the 1985–86 winter that
destroyed all of the mangrove nest sites in the Banana River and Moore Creek. Although 250 nests
were recorded in 1986 at Moore Creek, the storks abandoned the freeze-damaged rookery and no
successful nesting has occurred on the refuge since 1986. Approximately 250 wood storks currently
use the refuge for feeding and roosting.
Waterfowl
The refuge’s estuarine waters and impounded areas provide important habitat to both resident and
wintering waterfowl. Seventeen waterfowl species regularly use the refuge, although only mottled
ducks typically nest on the refuge. Waterfowl numbers on the refuge vary dramatically during the
year, with tens of thousands using the refuge during the winter months, but only an estimated several
hundred resident mottled ducks are present during the summer months. The refuge historically
supported vast numbers of wintering waterfowl, including blue-winged teal, American widgeon,
northern pintail, lesser scaup, redhead, and mergansers. However, wintering population numbers
have varied through the years with recent counts generally low. Of particular concern are northern
pintail and lesser scaup.
Pintail population numbers have steadily declined on the refuge over the past decades, from a
midwinter count of about 20,000 in 1978 to 8,315 birds in 1989, to 3,141 in 1999, and to a low of
1,376 birds in January 2003 (representing a 93 percent decline from 1978). The northern pintail
stands a serious chance of being extirpated from a historical wintering area at the refuge.
The continental population of lesser scaup has been declining since the mid-1980s. The Merritt Island
Refuge and its adjacent estuarine areas (in the Banana River, Indian River Lagoon, and Mosquito
Lagoon) provide the most valuable wintering habitat for scaup on the Atlantic Flyway, harboring up to 62
percent of the flyway’s scaup and 15 percent of the continental scaup population (Herring 2003).
Wading Birds
Sixteen species of wading birds (e.g., egrets, herons, and ibises) can be found on the refuge. Of
these, one is federally listed as endangered (the wood stork) and eight species are designated
Birds of Conservation Concern (BCC - federal) or Species of Special Concern (SSC - state) (see
40 Merritt Island National Wildlife Refuge
Appendix D for a list of designated species). Fourteen of these species commonly nest on the
refuge. Wading birds at the refuge use a broad range of wetland habitat types for foraging,
roosting, and nesting. Refuge habitats frequented by wading birds include both natural and man-made
features, including the open estuary, natural freshwater wetlands, impoundments, and
roadside ditches. In addition, many wading birds use vegetated dredge spoil islands in the Indian
River Lagoon and Banana River as roosting and nesting sites.
Shorebirds
As a result of its location along the Atlantic coast, the refuge provides valuable habitat to a wide
variety of shorebirds. Thirty-five species of shorebirds regularly use the refuge during fall and spring
migrations, taking advantage of habitat provided along the coast, along shore areas of the estuary,
and within impoundments. Fourteen species commonly winter on the refuge in high numbers and
seven species have been recorded as nesting on the refuge. Of the species that regularly use the
refuge, one species, the piping plover, is listed both federally and by the state as threatened, while
two other species (the red knot and semipalmated sandpiper) are federally designated as Birds of
Conservation Concern (see Appendix D). Suitable habitat for shorebirds is provided via the current
system of managing refuge impoundments for multiple species.
Passerines
The refuge hosts a great diversity of passerines, with approximately 170 species regularly occurring
on the refuge. While 38 species have been recorded nesting on the refuge, the greater majority of
passerines are transient, using refuge habitats during spring and fall migrations. The threatened
Florida scrub-jay (discussed above) is the only federally listed passerine that occurs on the refuge.
Mammals
The refuge’s mammalian fauna is characteristic of the central Florida coastal barrier ecosystem. Thirty
species of mammals are known to occur on the refuge, including two marine mammals (the West Indian
manatee and Atlantic bottlenose dolphin) which frequent lagoon and offshore waters. The refuge
provides important habitat for two federally listed species, the West Indian manatee (state and federally
listed as endangered) and the southeastern beach mouse (state and federally listed as threatened).
West Indian Manatee
Refuge waters serve primarily as a safe harbor and seagrass feeding site for an average of 300 West
Indian manatees (Trichechus manatus) year-round and may host a peak population of over 600
individuals during months with warm water temperatures. Over a third of Florida’s manatee population is
found in the Indian River Lagoon system (Indian River Lagoon National Estuary Program 1996).
Southeastern Beach Mouse
The federally threatened southeastern beach mouse (Peromyscus polionotus niveiventris) is a
subspecies of the old field mouse (P. polionotus) that inhabits the sand dunes and adjoining scrub
along the Atlantic coastline. Extensive coastal development has resulted in the loss of coastal dunes
and fragmentation of nearly all beach mouse habitats in Florida. The refuge provides habitat and
protection to one of the last remaining core populations of this species.
Comprehensive Conservation Plan 41
Reptiles and Amphibians
The refuge provides habitat to 71 species of reptiles and amphibians, including three marine reptiles
(the green, leatherback, and loggerhead sea turtles). Five species (American alligator, Eastern
indigo snake and the three sea turtles) are federally listed as threatened or endangered. Three
additional species are also listed by the state as species of special concern (the Florida pine snake,
gopher frog, and gopher tortoise) (see Appendix D).
Terrestrial herps have been studied on the refuge since the 1970s. Long-term monitoring has provided
considerable existing data on the biodiversity of herps on the refuge (Seigel and Pike 2003) and will be
invaluable to detect long-term changes in the refuge herpetofauna. Reptiles and amphibians are critical
components of refuge ecosystems. The biomass of reptiles and amphibians (i.e., herps) may exceed that
of all other vertebrates in aquatic and terrestrial systems (Seigel and Seigel 2000). The ecological
distribution of reptiles and amphibians on Merritt Island Refuge is a function of available habitat, which
mostly reflects wetland, freshwater communities. However, several species are specific to and use
terrestrial habitats and certainly are linked to the coastal ridge and trough topography on the refuge.
Exotic species are becoming potential threats to the refuge. Presently on the refuge, the brown anole
(Anolis sagrei) may be displacing native species (Campbell 2000; Campbell and Echternacht 2003). The
Cuban frog (Osteopilus septentrionalis), which consumes smaller species, has been positively identified
on the refuge. Additional research and monitoring is being conducted on gopher tortoise distribution,
fecundity, and on upper respiratory tract disease.
American Alligator
The American alligator (Alligator mississippiensis) is federally listed as threatened only as a result of its
similarity in appearance to the federally endangered American crocodile. The species is not regulated
under Section 7 of the Endangered Species Act and is not in danger of becoming extinct. American
alligators are abundant on the refuge, with an estimated population of over 3,000 individuals.
Eastern Indigo Snake
Eastern indigo snakes (Drymarchon couperi) became federally listed as threatened under the Endangered
Species Act in 1978. Once common from the southern tip of South Carolina west to southeastern
Mississippi and throughout Florida, the current range is restricted to southern Georgia and peninsular
Florida, with a few small populations located in the Florida panhandle and Key Largo. Eastern indigo
snakes have very large home ranges and use a variety of habitat types found within the refuge, including
oak scrub, oak hammock, pine flatwoods, fresh and brackish wetlands, and disturbed habitats (Breininger et
al. (2004). The species also shares a commensal relationship with the state-listed gopher tortoise
(Gopherus polyphemus), whose burrows it uses as shelter from predation and temperature extremes.
Sea Turtles
Three different sea turtle species annually nest along the nearly 10-kilometer stretch of refuge beach
between March and September. These turtles include the federally threatened loggerhead sea turtle
(Caretta caretta), federally endangered green turtle (Chelonia mydas), and federally endangered
leatherback turtle (Dermochelys coriacea). The loggerhead is the primary nesting turtle on the refuge
with over 95 percent of the nesting and with previous annual averages of 1,300 nests (Popotnik and
Epstein 2002). Green sea turtle nest numbers oscillate between 50 and 200 every other year.
Leatherback sea turtles nest infrequently on the refuge beach, with only one or two nests recorded in
a typical year. Management for these species includes beach protection, NASA coordination efforts,
nest monitoring during the nesting season, and predator control. Primary nest predators include
raccoons (Procyon lotor), feral hogs (Sus scrofa), and ghost crabs (Ocypode quadrata). Nest
depredation was greater than 90 percent of nests during the late 1970s before predator control (Lew
Ehrhart, personal communication). Today, an active predator control program has reduced the
42 Merritt Island National Wildlife Refuge
depredation of nests well below an annual rate of 10 percent. In addition, the disorienting effects of
artificial nighttime lights from NASA and U.S. Air Force facilities on nesting and hatchling sea turtles
are a concern. The NASA monitors this turtle disorientation annually. The refuge coordinates efforts
with NASA and the Air Force to help reduce or eliminate the adverse effects of nighttime lighting on
sea turtle nesting and hatchling disorientation.
Beyond the nesting beaches, the refuge also provides a juvenile sea turtle nursery. The Mosquito
Lagoon is considered a developmental habitat for sub-adult loggerhead and green sea turtles. The
lagoon once supported vast numbers of wintering juvenile sea turtles and an historic sea turtle fishery that
extended into the 1960s, which was thought to contribute to the decline in population numbers. Turtles
may remain in Mosquito Lagoon until maturity. Turtles wintering in the lagoon are plagued by winter
freezes, which can cold-stun the animals and cause mortality. The refuge has developed a plan to
coordinate the handling of cold-stunned turtles and prevent moralities (Epstein 2001a). Monitoring of
wintering sea turtles in the Mosquito Lagoon in the mid-1970s (Ehrhart and Yoder 1978) found higher
numbers than presently found (Provancha et al. 2002) and found an increase in sea turtle fibropapillomas.
Fish
More than 140 species of freshwater and saltwater fish are known to use refuge estuarine areas,
impoundments, and freshwater wetlands. Of the species known to occur in refuge waters, none are
currently federal- or state-listed species. Fish within the refuge are important not only to commercial
and recreational interests, but also to the ecology of the area. The refuge protects important fish
habitats, such as fish spawning and fish settlement sites, ensuring healthy, sustainable fish
populations. The open water estuary habitat of the Indian River Lagoon is one of the most renowned
sportfishing sites in the world (Roberts et al. 2001). This system is essential to several
interjurisdictional and economically important fish species, including snook, tarpon, red and black
drum, spotted seatrout, and striped mullet.
Invertebrates
A wide variety of marine, freshwater, and terrestrial invertebrates are found within the refuge’s
boundary. While some research has been conducted regarding benthic macro-invertebrates
inhabiting the open estuary and select impoundments, no systematic survey has been performed for
freshwater or terrestrial invertebrates of the refuge. A keystone species, the horseshoe crab (Limulus
polyphemus) which generally inhabits estuarine areas of the refuge, has been in decline (Jane
Provancha and Gretchen Ehlinger, Dynamac, Inc., personal communication). The reason for the
decline in horseshoe crab abundance is currently unknown.
Exotic, Invasive, and Nuisance Species
The occurrence and spread of exotic, invasive, and nuisance plant and animal species have been
identified by Service staff and intergovernmental partners as one of the priority management issues
facing Merritt Island National Wildlife Refuge. Further, nuisance native animal species are also
known to have negative impacts on threatened and endangered species and on human safety.
Although numerous exotic, invasive, and nuisance species occur on the refuge, only a small number
have been identified by the refuge as management concer