Terrestrial Forest Management Plan for Palmyra Atoll

Open-File Report 2011–1007

Prepared for The Nature Conservancy Palmyra Program

U.S. Department of the Interior

U.S. Geological Survey
Cover: Images showing native species of the terrestrial forest at Palmyra Atoll (on the 

left from top to bottom: red-footed boobies, an undescribed gecko, and a coconut crab). 

The forests shown are examples of Pisonia grandis forest on Lost Islet (above) and 

an example of coconut palm monoculture on Kaula Islet (below) at Palmyra Atoll. 

(Photographs by Stacie Hathaway, U.S. Geological Survey, 2008.)
Terrestrial Forest Management Plan for Palmyra Atoll

By Stacie A. Hathaway, Kathryn McEachern, and Robert N. Fisher

Prepared for The Nature Conservancy Palmyra Program

Open-File Report 2011–1007

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2011

For more information on the USGS—the Federal source for science about the Earth,

its natural and living resources, natural hazards, and the environment, 

visit http://www.usgs.gov or call 1–888–ASK–USGS.

For an overview of USGS information products, including maps, imagery, and publications,

visit http://www.usgs.gov/pubprod

To order this and other USGS information products, visit http://store.usgs.gov

Suggested citation:

Hathaway, S.A., McEachern, K., and Fisher, R.N., 2011, Terrestrial forest management plan

for Palmyra Atoll: U.S. Geological Survey Open-File Report 2011–1007, 78 p.

Any use of trade, product, or firm names is for descriptive purposes only and does not imply 

endorsement by the U.S. Government.

Although this report is in the public domain, permission must be secured from the individual 

copyright owners to reproduce any copyrighted material contained within this report.
iii

Contents

Executive Summary....................................................................................................................................................... 1

Introduction.................................................................................................................................................................... 3

Purpose, Development, and Review.......................................................................................................................... 3

Relation to Other Plans.............................................................................................................................................. 4

Value of Palmyra Atoll at Multiple Scales................................................................................................................... 4

Mission and Purpose of Palmyra Atoll Under Joint Ownership of TNC and the FWS.................................................... 5

Mission, Goals, and Refuge Purposes of the FWS National Wildlife Refuge System................................................ 5

Mission and Purpose of the TNC Palmyra Program................................................................................................... 5

Study Site ...................................................................................................................................................................... 6

Background and History of Human Use......................................................................................................................... 6

Inventory and Description of Habitat.............................................................................................................................. 7

Geography / Land Area.............................................................................................................................................. 7

Surface Water............................................................................................................................................................ 7

Groundwater .............................................................................................................................................................. 8

Geology and Soils...................................................................................................................................................... 9

Flora..........................................................................................................................................................................12

Dominant Vegetation Types ..................................................................................................................................13

Pisonia grandis Forest.......................................................................................................................................13

Coastal Strand Forest or Scaevola-Tournefortia................................................................................................17

Pandanus fischerianus ......................................................................................................................................17

Lepturus repens var. palmyrensis......................................................................................................................17

Coconut Palm Forest.........................................................................................................................................17

Terminalia catappa ............................................................................................................................................18

Hibiscus tiliaceus ...............................................................................................................................................18

Miscellaneous Species..........................................................................................................................................18

Vegetation Monitoring ...........................................................................................................................................19

Fauna........................................................................................................................................................................19

Mammals...............................................................................................................................................................19

Avifauna ................................................................................................................................................................19

Herpetofauna.........................................................................................................................................................20

Terrestrial Invertebrates ........................................................................................................................................21

Arthropods .........................................................................................................................................................21

Environmental and Human-caused Drivers and Stressors........................................................................................22

Storms...................................................................................................................................................................23

Climate Change.....................................................................................................................................................23

Direct Human Impacts...........................................................................................................................................24

Invasive Species ...................................................................................................................................................25

Conceptual Models of Palmyra Atoll Terrestrial Forest Ecosystems.............................................................................26

Components of the Terrestrial Ecosystem on Palmyra Atoll .....................................................................................27

Resources of Concern ..............................................................................................................................................27

Critical Assumptions and Uncertainties.....................................................................................................................28

Conceptual Modeling ................................................................................................................................................29

Habitat, Goals, Objectives, and Strategies ...................................................................................................................29

Goals and Objectives of the “Terrestrial Forest Management Plan for Palmyra Atoll”..................................................31

Management Goals, Objectives, and Strategies for the Palmyra Atoll Terrestrial Forest .............................................32
iv

Range of Natural Variation........................................................................................................................................32

Desired Future Conditions ........................................................................................................................................32

Objectives .................................................................................................................................................................34

(HG1-O1) Develop conceptual model(s) ...............................................................................................................34

(HG1-O2) Map historical islet boundaries..............................................................................................................35

(HG1-O3) Measure, classify, and map terrestrial vegetation.................................................................................36

(HG1-O4) Measure, classify, and map soils..........................................................................................................36

(HG1-O5) Measure, classify, and map groundwater .............................................................................................37

(HG1-O6) Maintain existing Pisonia grandis stands and promote new growth and expansion..............................38

(HG1-O7) Control coconut palm succession and incursion into Pisonia grandis stands that have suffered 

moderate to extensive mortality during the scale infestation. ................................................................................39

(HG1-O8) Create openings for native coastal shrubs to colonize monotypic coconut palm stands.......................40

(HG1-O9) Map contaminants. ...............................................................................................................................40

(HG1-O10) Remediate contaminants in priority areas...........................................................................................41

(HG1-O11) Evaluate potential short- and long-term impacts of climate change....................................................41

(HG1-O12) Maintain and increase genetic diversity ..............................................................................................41

(HG1-O13) Accelerate native forest restoration. ...................................................................................................42

(HG1-O14) Reintroduce former native fauna species extirpated from Palmyra Atoll.............................................43

Scope and Limitations of this “Terrestrial Forest Management Plan for Palmyra Atoll”.............................................43

Potential Workplan........................................................................................................................................................45

Phase 1.....................................................................................................................................................................45

Phase 2.....................................................................................................................................................................46

References Cited..........................................................................................................................................................47

Appendix: Phase 1 Workplan .......................................................................................................................................74

Tables

Table 1. Terrestrial plant species that have been identified at Palmyra Atoll.............................................................. 54

Table 2. Native terrestrial vascular plant species that have been identified at Palmyra Atoll with qualitative 

descriptions of their distribution and abundance.......................................................................................................... 58

Table 3. Collectors of vascular plants at Palmyra Atoll in chronological order............................................................ 59

Table 4. Mammal species identified at Palmyra Atoll.................................................................................................. 60

Table 5. Avifauna of Palmyra Atoll.............................................................................................................................. 61

Table 6. Herpetofauna using the terrestrial habitat at Palmyra Atoll........................................................................... 62

Table 7. Terrestrial native and nonnative arthropod species identified at Palmyra Atoll ............................................. 63

Table 8. Terrestrial crabs of Palmyra Atoll.................................................................................................................. 68

Table 9. Palmyra Atoll resources of concern .............................................................................................................. 69

Table 10. Experts consulted regarding Palmyra Atoll management planning.............................................................. 71

Figures

Figure 1. Map of Palmyra Atoll. .................................................................................................................................. 72

Figure 2. State-transition model for restoration of Pisonia grandis forest within Palmyra Atoll .................................... 73

Figure 1–1. Priority areas for coconut palm removal at Palmyra Atoll. ...................................................................... 78
v

Conversion Factors

Multiply By To obtain

Length

millimeter (mm) 0.03937 inch (in)

meter (m) 3.281 foot (ft) 

kilometer (km) 0.6214 mile (mi)

Area

square kilometer (km2) 0.3861 square mile (mi2)

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows:

°F=(1.8×°C)+32.
1

Terrestrial Forest Management Plan for Palmyra Atoll

By Stacie A. Hathaway, Kathryn McEachern, and Robert N. Fisher

Executive Summary

This “Terrestrial Forest Management Plan for Palmyra Atoll” was developed by the U.S. 

Geological Survey (USGS) for The Nature Conservancy (TNC) Palmyra Program to refine and expand

goals and objectives developed through the Conservation Action Plan process. It is one in a series of 

adaptive management plans designed to achieve TNC’s mission toward the protection and enhancement 

of native wildlife and habitat. The “Terrestrial Forest Management Plan for Palmyra Atoll” focuses on 

ecosystem integrity and specifically identifies and addresses issues related to assessing the status and 

distribution of resources, as well as the pressures acting upon them, most specifically nonnative and 

potentially invasive species. The plan, which presents strategies for increasing ecosystem integrity, 

provides a framework to implement and track the progress of conservation and restoration goals related 

to terrestrial resources on Palmyra Atoll. The report in its present form is intended to be an overview of 

what is known about historical and current forest resources; it is not an exhaustive review of all 

available literature relevant to forest management but an attempt to assemble as much information 

specific to Palmyra Atoll as possible.

Palmyra Atoll is one of the Northern Line Islands in the Pacific Ocean southwest of the 

Hawai`ian Islands. It consists of many heavily vegetated islets arranged in a horseshoe pattern around 

four lagoons and surrounded by a coral reef. The terrestrial ecosystem consists of three primary native 

vegetation types: Pisonia grandis forest, coastal strand forest, and grassland. Among these vegetation 

types, the health and extent of Pisonia grandis forest is of particular concern. Overall, the three 

vegetation types support 25 native plant species (two of which may be extirpated), 14 species of sea 

birds, six shore birds, at least one native reptile, at least seven native insects, and six native land crabs. 

Green and hawksbill turtles forage at Palmyra Atoll, and though rarely documented, beach nesting could 

be affected by terrestrial management actions. There are various nonnative or invasive species 

throughout the terrestrial ecosystem. The most notable examples of terrestrial invasive species include 

coconut palms (Cocos nucifera) and black rats (Rattus rattus). Although it is unclear whether they are 

nonnative, coconut palms are currently the most dominant plant across Palmyra Atoll. They compete 

with native plant species for space and resources and are potentially detrimental to sea birds dependent 

on native vegetation for roosting and nesting habitat. This competition in turn impacts nutrient resource 

availability, thereby reshaping energy flow in the ecosystem. Black rats are known to prey on groundnesting sea birds and are likely responsible for the lack of burrowing sea bird reproduction at Palmyra 

Atoll. In addition, they may be facilitating the invasion of other nonnative species and negatively 

impacting other native fauna. Although the extent and impacts of these and other nonnative and (or) 

invasive species are not fully understood, the extent and impacts are clearly a threat to the native species 

and one of the most urgent threats to the overall ecosystem integrity of Palmyra Atoll.
2

This “Terrestrial Forest Management Plan for Palmyra Atoll” addresses issues related to 

invasive species and other problems. Priority goals are established as are associated objectives and 

strategies. The overarching goal is to perpetuate and where possible restore terrestrial ecosystem 

integrity through the following techniques:

1. Habitat management:

2.

Maintain and enhance habitat to the extent possible to sustain thriving 

Pisonia grandis forest, coastal strand forest, endemic grassland, self-sustaining populations 

of sea birds, shore birds, coconut crabs, native lizards, and native insects.

Monitoring and assessment:

3.

Acquire information on distribution and abundance as needed 

for conservation of each resource of concern by developing monitoring and assessment 

programs relevant to local, regional, and global needs.

Research:

4.

Gather new information to facilitate conservation of terrestrial forest resources. 

This information will deal with the ecology of the terrestrial ecosystem. 

Planning:

In terms of ecosystem integrity, prevention is the most effective and efficient tool for managing 

invasive species. There are various potential pathways for introduction and spread of nonnative species 

within Palmyra Atoll’s terrestrial ecosystems, and these concerns have largely been addressed within the 

“Biosecurity Plan for Palmyra Atoll”. Several invasive species have already become established at 

Palmyra Atoll, however, and control of coconut palms and rat eradication are the major priorities for 

adaptive forest management action. Other critical steps to minimize the impacts and spread of invasive 

species include early detection through inventory and monitoring, as well as containment, control, and 

management of other nonnative species already established at Palmyra Atoll. These efforts in 

combination with research and education will serve to inform management decisions related to 

ecosystem integrity.

Achieve regional cooperation for conservation by developing a process to facilitate 

planning among relevant agencies and by working toward integration of resource concerns 

with land management plans at local to global levels.

Along with reinstating ecosystem integrity, this “Terrestrial Forest Management Plan for

Palmyra Atoll” aims to evaluate other risk factors that possibly may compromise the persistence of 

natural resources at Palmyra Atoll. To that end, an adaptive management process of monitoring and 

plan audit and review is highly recommended to ensure the implementation and efficacy of the 

management practices outlined above. In addition, it will be important to identify other stressors and 

threats to the terrestrial ecosystem to prioritize additional management actions. It is essential to develop 

partnerships with relevant agencies and participate in collaborative efforts to evaluate the best 

management practices for protecting and conserving these resources into the future, as well as to 

forecast and avoid potential problems over the long term.

We advise ongoing assessment of this “Terrestrial Forest Management Plan for Palmyra Atoll”, 

as it contains strategies that require widespread cooperation and coordination to be effective. The 

“Terrestrial Forest Management Plan for Palmyra Atoll” is a working document and subject to periodic 

review, refinement, and improvement as new information becomes available. The strategies associated 

with incipient and established nonnative species will continue to be developed and should be 

implemented in an adaptive management framework. Constant review and evaluation of these 

management procedures will provide important management information to improve protocols and 

methods. Refining conservation goals via feedback loops can improve the ability of TNC and their 

partners to make effective decisions in evaluating and conserving ecosystem integrity.
3

Introduction

This “Terrestrial Forest Management Plan for Palmyra Atoll” has been designed to assist The 

Nature Conservancy (TNC) in carrying out their Palmyra Atoll Program mission and achieving the 

Palmyra Atoll Program objectives. On the basis of assessments of the biological uniqueness and 

importance of Palmyra Atoll, TNC purchased the atoll in 2000 to preserve the biological diversity of

Palmyra. TNC now shares ownership of Palmyra Atoll with the U.S. Fish and Wildlife Service (FWS). 

In 2001, Secretary of the Interior Bruce Babbitt signed Secretary Order No. 3224, creating a submerged 

lands refuge, which included about 22 square kilometers (km2) of waters beyond the emergent land of 

Palmyra Atoll (Department of the Interior, 2001). This order was followed by the purchase of about 1.7 

km2and about 1 km2 of emergent land from TNC by the FWS in 2001 and 2006, respectively. 

Together, these parcels represent the current extent of the Palmyra Atoll National Wildlife Refuge. This 

joint ownership results in TNC working in collaboration with the FWS toward identifying and achieving 

consistent and compatible goals and objectives for Palmyra Atoll ecosystems. A working partnership 

between TNC and the FWS is very important, as an ecosystem approach to management requires 

partner collaboration and coordination for adaptive management at an ecosystem level to be successful.

Purpose, Development, and Review

This “Terrestrial Forest Management Plan for Palmyra Atoll” is intended to continue efforts 

begun by TNC and the FWS to develop effective and efficient management planning for Palmyra Atoll.

It presents the foundation for an adaptive management approach to the conservation and recovery of 

native Palmyra Atoll terrestrial ecosystems, as well as priority management needs under consideration

for inclusion in a comprehensive conservation plan for the Palmyra Atoll National Wildlife Refuge. As 

part of an adaptive management process, this plan will help move TNC toward a final, yet dynamic,

working document. It was developed in consultation with the FWS, TNC, U.S. Geological Survey 

(USGS), and academic scientists. This plan is based on current understanding of Palmyra Atoll’s 

ecosystem component composition, structure, and function from management documents, research 

results, and expert knowledge.

Management plans are composed to include specific strategies to address management goals and 

objectives. Each goal is intended to result in a desired future condition, a specific need for action, and 

objectives and associated strategies designed to achieve that action. Objectives and strategies are 

designed for implementation of management targets, restoration of conservation targets, threatened and 

endangered species recovery, regulations, research and educational partnerships, habitat preservation, 

and appropriate public uses over a multiyear period.

Elements of ecosystem management include sustainability, establishing goals, a sound basis in 

ecological models and understanding, recognizing the importance of biodiversity and structural 

complexity and the interconnectedness and dynamic character of ecosystems, the consideration of the 

range of spatial and temporal scales, the role of humans as necessary for achieving sustainable 

ecosystem management goals, and the importance of adaptability and accountability (Christensen and 

others, 1996). This approach requires managers to have access to extensive information and data about 

the system, including historical and baseline conditions, the interactions among the components of the 

ecosystem, and the consequences of natural and human-caused impacts.

Ecosystem management programs are developed with the knowledge that there are many 

uncertainties about the behavior of the complex and ever-changing ecological systems these plans are 

intended to conserve and manage (Christensen and others, 1996). It is unclear how ecosystems will 
4

respond to disturbances such as storms or management actions, some of which are spatially extensive,

more intense, or more frequent than the natural range of disturbance. Uncertainties exist because of lack 

of ecological information, including knowledge about species life histories, upon which models of 

ecological functioning can be built. Sampling bias, analytical error, and questionable quality of data can 

all contribute to uncertainty about the conservation strategy and management decisions (Atkinson and 

others, 2004).

Because management plans are faced inherently with limited knowledge and limited ability to 

make predictions, they should be designed to improve the understanding of the ecological systems that 

managers are attempting to conserve and restore. This design allows for evaluating management 

strategies as appropriate in an adaptive management framework. The strategies should include robust 

monitoring programs to track progress toward management objectives and should maximize ability to 

meet those objectives in a scientifically defensible and cost effective way while minimizing the risks to 

the ecosystem.

Inherent in the adaptive management approach is the assumption that as new information 

becomes available through management effectiveness monitoring and new research, management 

strategies will be adapted or altered to better meet the planned goals. Therefore, this plan should remain 

flexible, and implementation of approved actions should begin as resources become available. The 

evolving document will be used to continue developing the goals, objectives, and strategies necessary 

for achieving desired outcomes; plan implementation; a monitoring and evaluation framework; and

integration of ecosystem science, scientific research, information management, and education and 

outreach.

This document should be reviewed annually and constitutes an essential aspect of adaptive 

management, critical for identifying problems and modifying actions as necessary. It should be 

revisited at least once every 5 years with an intensive review and should be updated on the basis of new 

information from monitoring and relevant research.

Relation to Other Plans

This document is accompanied by the “Biosecurity Plan for Palmyra Atoll” (Hathaway and 

Fisher, 2010) and the “Draft Initial Monitoring Plan” (Lafferty and Kushner, 2008). Together, the three

documents provide a starting point for the management and monitoring activities necessary to carry out 

the TNC Palmyra Program Mission. The three documents have been drafted as separate pieces, but 

there are strong links between the terrestrial and marine ecosystems. They should ultimately be 

considered together for compatible and comprehensive management. These plans have been developed 

in accordance with information provided in other relevant plans, including the “Regional Seabird 

Conservation Plan” (U.S. Fish and Wildlife Service, 2005), “Pacific Islands Regional Shorebird 

Conservation Plan” (Engilis and Naughton, 2004), “Birds of Conservation Concern” (U.S. Fish and 

Wildlife Service, 2002), and “Waterbird Conservation for the Americas: The North American Waterbird 

Conservation Plan” (Kushlan and others, 2002).

Value of Palmyra Atoll at Multiple Scales

This document presents a strategy for maintaining and restoring the terrestrial components of 

Palmyra Atoll National Wildlife Refuge while acknowledging that it is part of the larger integrated 

terrestrial-marine ecosystem. The conservation and restoration of Palmyra Atoll resources contribute to 

a reduction in the current rate of loss of biological diversity locally, regionally, nationally, and globally. 

Palmyra Atoll is one of few remote, uninhabited, and protected terrestrial and marine ecosystems in the 

world. It is a great resource not only in and of itself but also as a natural management and monitoring 
5

laboratory for research on short-term and long-term responses to local, regional, and global 

environmental and human-caused stressors. Palmyra Atoll provides a place for development of 

management techniques that can be applied directly onsite and elsewhere.

Mission and Purpose of Palmyra Atoll Under Joint Ownership of TNC and the 

FWS

Mission, Goals, and Refuge Purposes of the FWS National Wildlife Refuge System

The mission of the FWS National Wildlife 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” (U.S. Fish and Wildlife Service, 2006). The purpose for 

which a refuge was established or acquired is of key importance to refuge planning and refuge 

purpose(s), and the refuge system’s mission forms the foundation for management decisions. The 

purposes of a refuge are specified or derived from the law, proclamation, executive order, agreement, 

public land order, donation document, or administrative memorandum that establishes, authorizes, or 

expands a refuge. The purpose of Palmyra Atoll National Wildlife Refuge, as stated in the Secretary’s 

Order, is “* * * to protect and preserve the natural character of fish, wildlife, plants, coral reef 

communities and other resources associated with the tidal lands, submerged lands, and waters of 

Palmyra.”

Maintaining ecological integrity is often cited as the primary goal of ecosystem-based

management, including the National Wildlife Refuge System Administration Act of 1966 as amended 

by the National Wildlife Refuge System Improvement Act of 1997, 16 U.S.C. 668dd-668ee (Refuge 

Administration Act) Section 4(a)(4)(B). One of the 14 directives of this law states that “In 

administering the System, the Secretary shall * * * ensure that the biological integrity, diversity, and 

environmental health of the System are maintained for the benefit of present and future generations of 

Americans * * *.” In addition, the Refuge Administration Act, as amended, clearly establishes that 

wildlife conservation is the singular National Wildlife Refuge System mission. House Report 105-106

accompanying the National Wildlife Refuge System Improvement Act of 1997 states “* * * the 

fundamental mission of our System is wildlife conservation: wildlife and wildlife conservation must 

come first.”

As stated in FWS 601 FW 3, it is the intent of the FWS to, first and foremost, maintain existing 

levels of biological integrity, diversity, and environmental health at the refuge scale (U.S. Fish and 

Wildlife Service, 2001). The FWS guidelines call for secondarily restoring lost or severely degraded 

elements of integrity, diversity, and environmental health at the refuge scale and other appropriate 

landscape scales where it is feasible and supports achievement of refuge purpose(s) and system mission. 

(Refer to 601 FW 3, available at http://www.fws.gov/policy/601fw3.html [accessed September 1, 2009],

for further explanation and definition of terms.)

Mission and Purpose of the TNC Palmyra Program

The mission and purpose of Palmyra Atoll National Wildlife Refuge, as stated by the FWS, are

in line with the TNC Palmyra Program mission “To preserve, protect and restore Palmyra’s unique 

ecosystem while facilitating valuable and responsible research through collaborative partnerships” (as 

posted at the Palmyra Atoll field station) and the TNC Palmyra Program management priorities, which 

include “protection and enhancement of wildlife habitat”
6

(http://www.nature.org/wherewework/asiapacific/palmyra/about/, accessed September 1, 2009). To

date (2010), management programs on Palmyra Atoll have been primarily focused on invasive species 

management, conservation of the Pisonia grandis forest, restoring altered lagoon hydrology, protecting 

sea bird nesting colonies, and providing opportunities for the public to learn about wildlife resources 

through wildlife viewing, interpretation, and recreation (U.S. Fish and Wildlife Service, 2007).

Study Site

Palmyra Atoll is at about 6°N, -162°W, about 1,600 km southwest of Honolulu (fig. 1). Palmyra 

Atoll is at the northern end of the Line Islands in proximity to the Intertropical Convergence Zone. The 

climate is characterized by high humidity (>90 percent) and warm temperatures (24–27 degrees Celsius 

[°C]). Palmyra Atoll is considered a wet atoll, receiving nearly 4,500 millimeters (mm) of rain per year 

(Sadler, 1959). References vary regarding the current number and size of islets, most of which are 

heavily vegetated; however, a land area of about 250 hectares (ha) was most recently estimated (Collen 

and others, 2009). The islets do not exceed 2 meters (m) in elevation and reportedly vary in size from 

about 0.1 to 97.9 ha. They are arranged in a horseshoe pattern around four lagoons surrounded by coral 

reef. The terrestrial ecosystem supports what have been considered some of the best remaining 

protected Pisonia grandis forest and large colonies of sea birds, including the second largest colony of 

red-footed boobies (Sula sula) in the world, as well as significant numbers of migratory shore birds.

Background and History of Human Use

Palmyra Atoll likely was explored by Micronesians and Polynesians but was never inhabited. 

The first sighting of the atoll by an American sea captain, Edmond Fanning, was in 1798; however, the

atoll was officially discovered and named in 1802 by Captain Sawle of the ship Palmyra. In 1859, Dr. 

G.P. Judd of the American brig Josephine claimed possession of the atoll for the United States and 

American Guano Co. In 1898 under the leadership of President McKinley, Palmyra Atoll was acquired 

by the United States through a Joint Resolution of the 55thCongress, which annexed the territory of 

Hawai`i, including Palmyra. In 1911, Judge Henry E. Cooper of Honolulu bought Palmyra Atoll and

later sold it to the Fullard-Leo family. There was a short period of military use from 1940 to 1945,

during which the atoll and lagoon were modified greatly. In 1947, the Fullard-Leo family reclaimed 

ownership by U.S. Supreme Court decision. In 1959, Hawai`i became the 50th State, but Palmyra Atoll 

was specifically excluded making it a privately owned U.S. Territory. There were attempts to identify a 

lucrative guano business and multiple attempts to plant coconut palms (Cocos nucifera) for copra, the 

dried meat of the coconut that is processed into coconut oil and copra meal (used as livestock feed); 

however, these ventures were unsuccessful. After the military left, use of the atoll gradually reduced in 

intensity with only a few known long-term stewards and occasional visits by recreational vessels. 

Infrastructure left by the military has continued to be used over time (for example, airstrip, dock, some 

of the roads), has been modified over time for use (for example, water catchment system), or has been 

essentially abandoned (for example, hospital building, bunkers, pillboxes). In 1987, the Department of 

the Army, U.S. Army Corps of Engineers, Pacific Ocean Division conducted a Defense Environmental 

Restoration Program inventory survey of Palmyra Atoll, which was identified and designated on 

January 2, 1992, as a Formerly Used Defense Site (FUDS) (R.M. Towill Corporation, 1993; Woodward, 

2001). Investigation, planning, and remediation activities to locate, evaluate, and remove debris and 

contaminated materials occurred through 1998 (Environmental Chemical Corporation, 1998).

In August 2000, TNC purchased emergent lands, and on January 18, 2001, by Secretarial Order 

No. 3224, Palmyra Atoll was established as an FWS national wildlife refuge. The refuge now includes 
7

all emergent land (with the exception of Cooper and Menge Islets, retained by TNC) and the oceanic 

area about 22 km2 beyond; however, there are nine areas of tidal and submerged lands containing 

munitions, vessels, or other materials excluded from this transfer totaling about 491.5 km2 that remain 

under the jurisdiction of the Deputy Assistant Secretary of Insular Affairs (Department of Interior -

Office of Insular Affairs, 2006). Palmyra Atoll, one of a few atolls without a long settlement or fishing 

history, is now managed for conservation and recovery of native habitats. It represents an important 

land type as one of two U.S. protected atolls currently supporting a sizable Pisonia grandis forest. Rose 

Atoll, in the Samoan archipelago, is the second atoll with Pisonia grandis forest; however, Rose Atoll is

considerably drier and supports a smaller Pisonia grandis forest with less structural complexity, these

differences make both atolls important for natural resource conservation.

Inventory and Description of Habitat

Palmyra Atoll is included in an ecoregion characterized by atolls with open or closed lagoons or 

raised reef platforms with an elevation of less than 4 m (Mueller-Dombois and Fosberg, 1998). Despite 

low endemism and biodiversity in general, these islands protect various natural resources. For example, 

they support some of the largest populations of sea birds in the world and provide wintering and 

stopover habitat for migratory shore birds. The majority of these islands have undergone heavy 

disturbance from activities such as military use, phosphate mining, attempts to establish copra 

plantations, and invasive species introductions.

In general, the historical habitat conditions of Palmyra Atoll are not extensively known. 

Dawson (1959) provided a good summary of the known history of Palmyra Atoll and attempted to 

describe the changes that have taken place on the basis of his observations in comparison to the 

literature available at the time. For example, there are records of plant collections and descriptions of 

the vascular flora of Palmyra Atoll dating as far back as 1873. Dr. Thomas Streets described Palmyra 

Atoll’s emergent land as “thickly clothed with vegetation.” He also described sooty terns (Onychoprion 

fuliginosa) breeding at the extreme eastern point of the island in numbers so large that they formed a 

cloud when driven from the ground, and “their clamor deadens the roar of the surf” (Streets, 1877). 

Rock (1916, 1929) provided similar details on another expedition to the atoll.

Geography / Land Area

Collen and others (2009) investigated historical maps, navigational charts, and photographs, as 

well as anecdotal evidence, from 1874 to 2007 and showed that Palmyra Atoll islets originally 

underwent minor natural changes in shape and size. They also documented modifications to Palmyra 

Atoll from military construction, including lagoon dredging, the creation of islets, and increased 

terrestrial connectivity. With these modifications most of the islets of the atoll were enlarged and 

connected above sea level, resulting in the doubling of land area and almost tripling of land volume. 

While there has been significant alteration to the geography of the atoll by military occupation, natural 

processes have already begun breaking down these changes, and lagoon circulation is beginning to be 

reestablished.

Surface Water

Christophersen (1927) mentioned freshwater on Holei Islet at a depth of 28 cm below the surface 

of a muddy depression. He suggested that this may have been the same depression found by Rock 

(1916, p. 22) searching for the location of a freshwater pond as indicated on charts. He went on to 

suggest that a freshwater pond would be intermittent, rising above surface in only wet seasons. In both
8

accounts of freshwater on Holei Islet, the surrounding vegetation is described as coconut palms, ferns, 

and Pandanus. Currently (2010), there are patches of hau (Hibiscus tiliaceus) on Pelican Islet and on 

the southern end of Home Islet, which also appear to hold surface water intermittently (S. Hathaway, K. 

McEachern, and R. Fisher, U.S. Geological Survey, oral commun., 2008). There are two other areas, 

one on Cooper Islet and one on Paradise Islet, which support surface water. On Cooper Islet, the area 

has been described as an artificial freshwater pond, formerly a cesspool built during military use and 

recently found to support a stock of freshwater eels (Handler and James, 2006). No other information 

regarding the origin or status of these freshwater sites was found.

Groundwater

Little is known about the groundwater at Palmyra Atoll or the role that it is playing in ecosystem 

function. Freshwater recharge at coral atolls occurs when infiltrating rainwater displaces the underlying 

saltwater from the surrounding ocean to form a lens of fresh groundwater. Freshwater lenses in atoll 

settings are thin vertically relative to their areal extent (Tribble, 2008).

It is unknown whether any groundwater lenses are present at Palmyra Atoll (Suchanek and 

others, U.S. Geological Survey, written commun., 2007; J. Kulongoski, U.S. Geological Survey, oral 

commun., 2008). It is also unclear to what extent the native flora and fauna might be dependent upon 

them or whether they are affected by nonnative species. The size and depth of freshwater lenses are 

directly related to the size of the islet. While there does not appear to be any clear delineation of 

minimum size (as reviewed in Lee, 1984), Underwood and others (1992) modeled recharge rates of 

freshwater lenses and found that, under the assumption that a minimum threshold thickness of 2–3 m is 

required to maintain a developable lens, 250 m (the smallest width tested) would be the minimum island 

width necessary to support freshwater lens dynamics. More recently Bailey and others (2009) used the 

most inclusive conceptual model available (Ayers and Vacher, 1986) to model atoll freshwater lens 

response to climatic factors and geologic variables. They used widths as low as 150 m in simulations, 

and results indicated there would likely be a temporary loss of the freshwater lens during the drought 

effects of El Niño at the lower width atolls. Because of the relatively small islets composing Palmyra 

Atoll, these studies would indicate there were probably few, if any, freshwater lenses present 

historically. In contrast, dimensions of 60 m were reported as suitable for freshwater lens development 

at Herald Cays (G.N. Batianoff, G.C. Naylor, and H.A. Dillewaard, Queensland Herbarium, written 

commun., 2007 in Greenslade, 2008). Over time, Palmyra Atoll may provide data on these lower limits 

tested by Bailey and others (2009) and Underwood and others (1992).

In addition, investigating the presence of freshwater lenses at Palmyra Atoll may be especially 

worthwhile given current interest in developing artificial islands through lagoon dredging and creating 

water reserves for other Pacific Islands (Falkland, 2002, in White and others, 2007). White and others 

(2007) pointed out negative environmental impacts as a result of dredging. The existing augmented 

land area at Palmyra Atoll may be worth examining for freshwater lenses as an initial feasibility 

investigation. Likewise, Palmyra Atoll serves as an example for some of the negative environmental 

impacts that can result from dredging, though there are completely humanmade islets where Nonner and 

Woodward (2006) found Pisonia grandis forest to be healthier than on other naturally formed islets. 

They suggest that this phenomenon may be due to slightly higher elevation, which makes the Pisonia 

grandis forest less susceptible to tidal fluctuation and storm events capable of increasing saltwater 

intrusion of the water table.

Groundwater is most likely to be more widely present at Palmyra Atoll as a saturated zone. 

During contaminants investigations at Palmyra, it was reported that the subsurface water table was 

generally 0.6–1.2 m below the ground surface and tidally influenced (Environmental Chemical 
9

Corporation, 1998). To provide insight into plant use of any existing groundwater, Nonner and 

Woodward (2006) suggested methods examined by O’Grady and others (2006) in which isotopic 

analyses of both oxygen and hydrogen in potential water sources could be compared with analyses of 

xylem water in relevant plants to reveal the source of uptake. While it is known that Pisonia grandis

has a shallow root system (Walker, 1991), it is unknown whether the trees are largely dependent on 

rainfall and near surface moisture or whether they rely on reaching groundwater especially during drier

periods. If the latter were the case it would be important to determine if groundwater levels are being 

lowered because of heavy consumption by coconut palms, a species also known to have a rather shallow 

root system. Walker (1991) suggested that Pisonia grandis has a shallow root system adapted to using 

near surface water and avoiding contact with the water table.

Use of groundwater by terrestrial fauna, such as burrowing crabs (which are dependent on

moisture for their physiology), is unknown for Palmyra Atoll. Gross (1964) indicated that coconut 

crabs (Birgus latro) and land hermit crabs (Coenobita sp.) can control blood concentration by selecting 

water of appropriate salinity, but given a choice coconut crabs prefer freshwater and the strawberry 

hermit crabs (Coenobita perlatus) prefer seawater. Wood and Boutilier (1985) found freshwater in the 

burrows of the orange land crab (Cardisoma carnifex) but noted that they also readily entered seawater. 

If native biota do use and require the presence of freshwater as lenses or groundwater, it will be 

important to assess their vulnerability to saltwater intrusion.

In addition to the uncertainty of groundwater sources, such as whether freshwater lenses exist on 

Palmyra Atoll, it is not clear if water sources have been compromised by contaminants (J. Kulongoski, 

U.S. Geological Survey, oral commun., 2008). Only some water sources were tested for remediation 

during FUDS investigations. For areas subject to remediation, groundwater samples were taken at the 

water table. Of the measurable contaminants found so far, the levels were considered low enough for 

safe human use of the area but were not tested for potentially negative effects to biota (Environmental 

Chemical Corporation, 1998; Wil Chee Planning Inc. and SCS Engineers, 1998). Contaminant 

assessments of the hospital dump site found various contaminants in the groundwater, but the levels did 

not exceed U.S. Environmental Protection Agency Maximum Contaminant Levels for drinking water. 

The assessments considered that because terrestrial and marine organisms use the dump sites this 

indicated that ecological risk was minimal. None of the measurable contaminants found so far have 

been identified as phytotoxic (L. Woodward, U.S. Fish and Wildlife Service, written commun., 2009). 

More recent surveys have begun, and preliminary results are pending (Suchanek and others, U.S. 

Geological Survey, written commun., 2007; D. Papoulias, U.S. Geological Survey, oral commun., 

2008). It is unclear whether the nuclear testing conducted by Great Britain and the United States in the 

1950s and 1960s at nearby Malden and Christmas Islands might have resulted in radioactive 

contamination at Palmyra Atoll because of fallout (Aronson and Anderson, 2000; Woodward, 2001). 

The FWS considered the need for testing for radioactive materials and determined it was not a major 

issue of concern at the time of their assessment (Woodward, 2001). It is unknown whether any 

contaminants have persisted in groundwater or if they are having negative effects on native plant and 

animal species.

Geology and Soils

Palmyra Atoll is part of the Line Islands seamount chain and is one of only twelve of these 

seamounts rising from a sea floor that extends above sea level (Keating, 1992). There are few 

references to the soil of Palmyra Atoll. Rock (1916) mentions the lack of soil or humus on Home Islet 

and describes its composition as loose coral fragments, sand, and guano phosphate. Regarding Holei

Islet, he describes huge solid blocks of phosphate rock and a 5-cm layer of black humus. These 
10

accounts are consistent with descriptions of other atolls supporting both Pisonia grandis forest and large 

numbers of sea birds. In fact, a phenomenon was described by Fosberg (1954, 1957, 1994) in which 

Pisonia grandis humus with a pH of 6.0–4.0 accumulated and combined with bird guano and rainwater 

to create a phosphate hardpan.

We found only one other reference to the soils of Palmyra Atoll for the time period before 

military activity. Christophersen (1927) described soils on some of the islets, including Home Islet, 

Holei Islet, Papala Islet, and Islet A (possibly now referred to as Fern) and Islet B (which appears to be 

north of Engineer Islet or Tanager Islet), in relation to the vegetation. He reported on the soils of Holei 

Islet with beach crests having light grayish brown coral sand, similar to Home Islet and supporting tree 

heliotrope (Tournefortia argentea). He described the interior of Holei Islet as supporting a forest of 

Pisonia grandis and Neisosperma oppositofolia, with no or very shallow soil composed of a brown to 

black mold with high water content and acidic pH. Where soil was absent on Holei Islet, 

Christophersen (1927) describes a coral hardpan almost completely transformed to calcium phosphate 

and about 10–20 cm thick under which he found yellowish white coral sand. In the eastern part of Holei

Islet, forested with coconut palms and Pandanus, he reported soil composed of dark gray sand, alkaline 

and moist (but drier than soil associated with Pisonia grandis), and a low percentage of organic matter 

and no hardpan in any place. Islet A was covered by a dense growth of coconut palms with a 

Phymatosorus scolopendria understory and only a few tree heliotrope. Christophersen (1927) described 

two types of soil on Islet A with the majority being brown to black moldy sand dispersed in gravel, 

alkaline with moderate water content, and high in organic content for a sandy soil. Other parts of the 

islet had a peaty, strongly acidic soil layer with high water content covering the sand. No hardpan was 

present. Islet B, also dominated by coconut palms but with a bird’s nest fern (Asplenium nidus)

understory and few tree heliotrope, had soil described as brown, moldy sand in gravel, moist, and 

alkaline. Again, no hardpan was present. At that time, Papala Islet supported a pure stand of Pisonia 

grandis with the exception of a single coconut palm. As such, soil conditions on Papala Islet were very 

different from those Christophersen (1927) described as supporting coconut palms. The soil was 

shallow dark brown to peaty mold, strongly acidic, moist, and almost entirely composed of organic 

matter underlain by a hardpan of coral conglomerate almost completely transformed into calcium 

phosphate.

Much of the current substrate of Palmyra Atoll has been altered since then through military 

modifications. There was extensive dredging in the lagoon to create a channel and remove obstructions. 

The resulting dredge materials were distributed throughout the atoll to connect most of the islets via 

causeways. In addition, the North and South Fighter Strips were created and connected by causeways, 

and the isolated islets of Sand, Leslie, Dudley, and Ainsley (and four islets around the dredged channel 

that are no longer present) were created from these dredge materials (Dawson, 1959). Keating (1992) 

cited the Great Britain Naval Intelligence Division Geographical Handbook Series (1943) describing the 

soils as variable across islets with beach crests characterized by grayish brown sand, low organic 

material, and high water content and most interior soils as brown with high organic material and 

moisture content or as thin soil overlying hard coral ground, reportedly calcium phosphate, underlain by 

yellow sand. We have been unable, however, to procure the geographic handbook, and it is unknown 

whether these assessments were made before or after military modification.

Current investigations of soil have also been limited, and comparisons to the past assessments 

have not been made. Wil Chee Planning Inc. and SCS Engineers (1998) reported a soil investigation at 

Quail Islet that resulted in a shorefront sequence and inland sequence. The shorefront sequence 

consisted of 15–30 cm of light-brown, compact, limey sand with coral fragments overlying about a 

meter of white coral marl with a basement of poorly consolidated detrital limestone. The inland 
11

sequence was associated with heavy vegetation and consisted of 8–30 cm of very soft, dark brown to 

gray limey silts, and silty sands over 30–60 cm of dark gray coral marl with a white limey coral 

basement. They found that surface debris and recognizable fill materials were generally not found in 

soil horizons greater than 60 cm below ground surface. Aronson and Anderson (2000) reported on soils 

from Cooper Islet and found a top layer of about 10 cm of dark gray to very dark gray, brown, silty 

sand, with loose granular sediments and an abundance of roots and historical debris. This layer was 

followed by a 21-cm-thick deposit of pinkish white fine to very fine sand along with cobbles and 

coralline gravel. From even more recent investigations, it appears that some areas are composed of 

shallow soil layers covering dredge materials, in contrast to perhaps less altered areas where the soil 

layer is deeper and underlain by sand (H. Young, Stanford University; J. Collen, Victoria University of 

Wellington, oral commun., 2008). There has been no known atoll-wide study with regard to soils,

however, and the role that soils and soil quality are playing in the terrestrial ecosystem is uncertain. 

Uncertainties include the relation of soil to living organisms, such as plant distribution, and whether 

there are nutrient deficiencies affecting ecosystem integrity. For example, the presence or absence of 

mycorrhizae in the soil may affect Pisonia grandis health. Recent studies have shown that Palmyra’s 

coral-derived soils are broadly nutrient deficient and vary significantly in nutrient levels across forest 

types (H. Young; written commun., 2009; Young and others, 2010a). They found the loss of 

allochthonous subsidies from sea bird-derived inputs in coconut palm forests compared to sites 

dominated by Pisonia grandis and tree heliotrope where birds prefer to nest and roost. While they found 

no significant difference in soil nutrients in Pisonia grandis and tree heliotrope forests whether they 

were from “natural” islets or those created from dredge fill, they found significantly lower nutrients on 

dredge fill islets versus “natural” when dominated by coconut palms. In addition, they found 

corresponding differences in trace elements by forest type with 5 of the 12 tested differing significantly.

As with groundwater, investigations for soil contaminants occurred at areas subject to FUDS 

remediation. Soil samples were taken at these locations, and any measurable contaminants found were 

considered at low enough levels for safe human use of the area. The soil samples were not tested for 

potentially negative effects to biota, though it was mentioned that a small site was determined to be at 

low ecological risk of contamination. The investigators found some soil contaminant “hot spots” but 

determined that remedial restoration was unnecessary unless the areas were intended for human 

habitation (Wil Chee Planning Inc. and SCS Engineers, 1998). Investigators considered continued 

terrestrial and marine organism use of the area to indicate minimal ecological risk; however, further 

remedial actions were recommended at several sites (Environmental Chemical Corporation, 1998; Wil 

Chee Planning Inc. and SCS Engineers, 1998).

Preacquisition studies conducted by the FWS in 2000 revealed elevated levels of metals, 

polychlorinated biphenyls (PCBs), and semivolatile petroleum hydrocarbon compounds, as well as 

slightly elevated arsenic levels, at terrestrial and intertidal locations. It was suggested that additional 

sampling be carried out to delineate the nature and extent of contamination. At that time, it was 

expected to cost about $28,000,000 for additional remediation of identified emergent land areas 

(Woodward, 2000). In response to the FWS, the U.S. Army Engineer District, Honolulu acknowledged 

that they had undertaken approved remediation activities and that if funding became available in 

accordance with FUDS guidance and headquarters approval they would further remediate the sites 

identified as still contaminated at Palmyra Atoll. This sampling/remediation has not yet taken place; 

however, other contaminant surveys have recently begun, and preliminary results are pending (D. 

Papoulias, U.S. Geological Survey, oral commun., 2008). It is not known whether there are still 

problem areas or how they are affecting ecosystem integrity. As mentioned with respect to 

groundwater, it is unclear whether the nuclear testing conducted by Great Britain and the United States 
12

in the 1950s and 1960s at nearby Malden and Christmas Islands might have resulted in radioactive 

contamination at Palmyra Atoll because of fallout (Aronson and Anderson, 2000; Woodward, 2001). 

The FWS considered the need for testing for radioactive materials and determined it was not a major 

issue of concern at the time of their assessment (Woodward, 2001).

Flora

There are records of collections and descriptions of the vascular flora of Palmyra Atoll dating at 

least as far back as 1873 (Streets, 1877; Rock, 1916, 1929; Dawson, 1959; Herbst, 1988, 1992; Depkin, 

2002; Freeman, 2006a, b). The most recent surveys, completed by Derral R. Herbst in 1987 and 1992 

(and subsequent identification of two additional species sent to him in 2002), provide a vascular plant 

species list and a brief description of the primary plant associations. These were later updated by 

Freeman (2006a, b). According to Herbst (1988, 1992) three main vegetation associations—including 

Pisonia grandis forest, coastal strand forest (Scaevola-Tournefortia), and coconut palm forest—were 

observed on the islets. Other minor vegetation types occurred but were so small that they would not be 

plotted on a conventional vegetation map (Herbst, 1992). Some quantitative descriptions of species 

abundance and distribution exist within these records, but there are limits to our ability to quantify how 

vegetation has changed across Palmyra Atoll over time.

Records indicate as early as 1862 the presence of coconut palms and what Rock (1916) 

concludes was likely either Pisonia grandis or Suriana maritime and that food plants were being 

introduced to the atoll (report from Zenas Bent while he was there under commission by King 

Kamehameha IV to take possession of Palmyra under the Hawai`ian flag [Rock, 1916]). Following

Rock’s (1916) account describing 15 species of vascular plants, including coconut palms (which many

assume to be a Polynesian introduction), many additional species were added to the list of native and 

nonnative species. (“Native” refers to plants that arrived without the aid of humans). Some of the 

species added to this list were likely present when Rock visited in 1913 but were not encountered or not

recognized at the time. The native Guettarda speciosa was collected on the atoll in 1949, but several 

other species were not recorded until much later. These species include Cordia subcordata, Hernandia 

sonora, and Barringtonia asiatica (Herbst, 1988, 1992), and it has been assumed that they arrived at 

Palmyra Atoll relatively recently without human intervention. While unlikely to give a complete 

prehistoric snapshot of the flora of Palmyra Atoll, paleoecological techniques of collecting and 

analyzing fossil pollen could help resolve some of the uncertainties of what species were present over 

time.

The practice of introducing and cultivating plants for food and as ornamentals continued until 

recently (Freeman, 2006a), but the list of unintentional introductions is also large. Some introduced 

plant species were unable to persist, but many are naturalized. The total vascular flora identified in past 

and current records at Palmyra Atoll includes 129 species. Of these species, 25 are considered native (2 

of these may now be locally extinct); 48 were cultivated ornamentals or food plants; and 56 were 

adventive or naturalized (table 1, table 2) (Herbst, 1988, 1992; Freeman, 2006a, b). Reviewing recent 

assessments of the number of terrestrial vascular plant species known to be present on Palmyra Atoll,

Freeman (2006a) suggests that 78 vascular plant species were still present on the atoll in 2006. Twentyfive of these were considered native species, meaning 53 nonnative species were considered still 

present. In reviewing the recent overall species lists drafted, however, several species had contradictory 

information regarding their current status, and it may be that some species are still present while others 

have since gone locally extinct or been extirpated. One species, Lepturus repens var. palmyrensis is 

considered endemic to Palmyra Atoll. A list of previous collectors of the vascular plants of Palmyra 

Atoll (from Herbst, 1992) is presented in table 3, and lists of vascular plants known to be recorded from 
13

Palmyra Atoll with generalized indication of the extent of islet distribution and abundance as begun by 

Herbst (1992) and updated by Freeman (2006a) are presented in tables 1 and 2. For more detailed 

information for each species by islet see Freeman (2006a).

Dominant Vegetation Types

The aseasonal climate with high precipitation and warm temperatures on Palmyra Atoll supports 

dense vegetation of native and nonnative trees, shrubs, and herbaceous understory plants. Mapping 

efforts from 2001 imagery (Wegmann, 2005) estimated that a large portion of the atoll (about 43 

percent) lies under a canopy of possibly nonnative coconut palm followed by native beach naupaka 

(Scaevola sericea) and tree heliotrope (about 29.5 percent) and Pisonia grandis (about 12 percent). 

Other vegetation types include broadleaf forests dominated by possibly nonnative tropical almond 

(Terminalia catappa) (about 6.2 percent), possibly nonnative hau (about 0.5 percent), and native 

Pandanus fischerianus (Wegmann, 2005). Understories include Lepturus repens grassland, 

Phymatosorus scolopendria stands, and bare ground (Wegmann, 2005). The vegetative zonation at 

Palmyra Atoll is spatially influenced by windward-leeward exposures and soil-groundwater influences. 

Natural temporal succession within these communities has been shaped by biophysical interactions and 

natural disturbance regimes from strong winds and cyclones, precipitation, sea bird-derived nutrients, 

and herbivory.

Pisonia grandis Forest

Pisonia grandis is a large, fast growing tree with soft wood reaching heights of 25 m on Palmyra 

Atoll (Herbst, 1992). The distribution of Pisonia grandis is limited to small remote islands in the Indian 

and Pacific Oceans (Airy Shaw, 1952) and was described in the 1890s as one of the “commonest most 

conspicuous forest types on coral islands throughout islands visited by the U.S. Fisheries Commission 

Albatross cruises” as reported by Alexander Agassiz (in Fosberg, 1994). It is now considered to be in 

widespread decline largely because of human activities (Walker, 1991). Individual trees reproduce 

almost entirely vegetatively, though they have sticky seeds thought to facilitate long-distance dispersal 

by remaining attached to sea birds (Burger, 2005). Carlquist (1974, in Walker, 1991) found little 

Pisonia grandis genetic differentiation across its Pacific range, suggesting that bird dispersal was

effective enough at reintroducing genes to overcome local incipient speciation. This genetic evidence

suggests an additional importance beyond the short-term benefit sea birds provide by adding nutrients to 

the system via guano; they may be increasing plant species genetic diversity over a long time period by 

dispersing seeds.

The factors influencing the pattern of distribution and growth of Pisonia grandis preclude a 

simple explanation. For instance, Pisonia grandis is found on both very wet and very dry atolls, with 

and without guano inputs. Walker (1991) suggests multiple contributing factors, including low 

dispersal frequency, guano effects, precipitation patterns, competition, insect grazing, genetic variation, 

and mycorrhizal associations. He points out that Pisonia grandis would likely be dispersed widely by 

sea birds through uncharacteristic dispersal events, such as cyclone scatter of sea birds; however, on 

islands in relative proximity to one another Pisonia grandis may be present on one island and absent on 

another. While it has been suggested that Pisonia grandis requires guano for growth, its distribution 

shows that this is not necessarily the case provided the soil contains adequate nutrients (Wiens, 1962; 

Spicer and Newberry, 1979). Pisonia grandis is found at the wettest (for example, about 4,500 mm/yr 

at Palmyra Atoll) and very dry islands (for example, Vago Island about 70 mm/yr) (Bell, 1969, in 

Walker, 1991). As mentioned previously, Walker (1991) suggests that Pisonia grandis has very 

shallow roots adapted for using near surface water. Keith (in Airy Shaw, 1952) describes Pisonia 
14

grandis as intolerant of shade and competition. In fact, vegetative growth does not appear to be 

hindered by herbaceous competitors, as Pisonia grandis resprouts readily under dense Phymatosorus 

scolopendria at Palmyra Atoll (S. Hathaway, K. McEachern, and R. Fisher, U.S. Geological Survey; W. 

Smith, U.S. Fish and Wildlife Service, oral commun., 2008). Walker (1991) suggests that Pisonia 

grandis competes with other woody vegetation by establishing a canopy more quickly than other 

species, as well as through modification of the soil pH. Common pH ranges from coral sand at 8.3 to 

“normal humus” at 7.0 to Pisonia grandis humus at 6.0–4.0 (Fosberg, 1957). Walker (1991) also notes 

that Pisonia grandis may develop dominance in areas of nutrient-poor soils via a symbiotic relation with 

an ectomycorrhizal mycobiont (a mutualism between a plant root and a fungus). As summarized in 

Nonner and Woodward (2006), Schmidt and others (2004) found that Pisonia grandis appears to 

acquire nitrogen as ammonium when deposited bird guano (largely uric acid) rapidly hydrolyses to 

ammonium. Guano also degrades to nitrate which is generally of low availability for uptake and 

assimilation in plants. Through an ectomycorrhizal association, Pisonia grandis may be able to acquire 

transiently available forms of nitrogen that result from the degradation of uric acid. At least two species 

of mycobiont have been found in association with Pisonia grandis with one or both occurring with the 

majority of samples taken, although certain samples contained no mycobionts (Ashford and Allaway, 

1985; Chambers and others, 2005). This association could give Pisonia grandis a competitive 

advantage over other species particularly in nutrient-poor soils. Pisonia grandis is largely associated 

with sea birds where nutrient input is high, and there is speculation that the ectomycorrhizae may 

protect the roots or perhaps use nutrients quickly before they are leached away by rains (Allaway and 

Ashford, 1984; Ashford and Allaway, 1985). Conversely, it is possible that Pisonia grandis takes 

advantage of nutrient-poor coral soils and becomes established and then attracts birds. This possibility 

would require that seeds (or viable branches) and mycobionts arrive together. Given the sticky nature of 

the Pisonia grandis seeds this would not be entirely unreasonable (Chambers and others, 2005). The 

presence of ectomycorrhizae at Palmyra Atoll and potential relation to the health of this tree are 

presently unknown (Nonner and Woodward, 2006).

Christophersen (1927) describes the vegetation from his visit in 1924 thus: “most of the islets 

composing Palmyra are covered by vigorous forests of coconuts and Pisonia fringed by Tournefortia on 

the beach crest.” Herbst (1992) considers that the vegetation prior to human visitation was probably 

predominantly Pisonia grandis forest fringed by coastal strand forest and suggests that Pisonia grandis

was probably largely cleared by Polynesians to establish coconut palm groves and possibly for 

firewood. These activities have happened to a greater or sustained extent across its range, leaving the 

current forest at Palmyra Atoll to be considered one of the best remaining Pisonia grandis forests 

worldwide, though it has recently been in decline. Other locations with Pisonia grandis forest have 

historically been described as having no other species of trees in the understory with little to no 

groundcover or with a fern understory (Hatheway, 1955; Kepler and Kepler, 1994). Likewise, Rock 

(1916) describes this fern understory as typically bird’s nest fern, although the primary understory today 

(2010) is Phymatosorus scolopendria. Freeman (2006a) reports that botanists collecting plants as late 

as the 1990s did not observe the dense ground cover of Phymatosorus scolopendria ferns now common 

in many of the open stands and canopy gaps of the islands. Instead like Rock (1926), older reports 

indicate a more open understory and greater cover of bird’s nest fern. Freeman 2006a hypothesized that 

the Phymatosorus scolopendria increase occurred after about 2000 possibly in response to changes in 

the ecosystem such as the rat eradication trial, the scale outbreak, storm overwash, weather, or some 

other atoll-wide environmental phenomenon, all of which may have contributed to the Pisonia grandis

die off (2001–6) and thus widespread formation of light gaps.
15

In 2001, the FWS began collecting quantitative vegetation data on Palmyra Atoll as a pre-rateradication baseline (Depkin, 2002). During this period, it was observed that the Pisonia grandis stands

were declining. As the trees were more closely investigated, it became apparent that there was a high 

density of a nonnative scale insect, Pulvinaria urbicola (Depkin, 2002). It is thought that the Pisonia 

grandis decline is likely a stress response from elevated numbers of the introduced scale and their 

symbiotic relation with the introduced ant Pheidole megacephala (Handler and others, 2007). The 

direct and indirect effects of scale on plants were reviewed in Nonner and Woodward (2006) largely 

citing Vranjic (1997). Direct effects include depletion of nutrients, tissue damage, accumulation of 

honeydew that can promote sooty mold and thereby reduce photosynthesis, and the redirection of 

resources toward growing new shoots instead of roots. Gerhing and Bennett (2009) note that the 

paucity of studies makes it impossible to make conclusions regarding plant response to level of scale 

infestation. Similarly, Nonner and Woodward (2006) note that sooty mold was present on other plants 

at Palmyra Atoll but was largely absent from Pisonia grandis. These conditions still persist today 

(2010). Indirect effects of the scale insect can include a loss of root structure, resulting in desiccation 

and possibly loss of ectomycorrhizal associations that could impede nutrient uptake. These direct and 

indirect effects result in reduced plant health and potentially the death of the plant.

In response to the declines and at the height of the scale infestation, the FWS began conducting 

quarterly Pisonia grandis censuses, beginning in 2004, to examine tree health and presence of scale

(Nonner, 2005, in Nonner and Woodward, 2006, 2008; Nonner and Woodward, 2006). The FWS found 

that numbers of Pisonia grandis trees declined 34 percent between 2002 and 2005 with an areal extent 

reduced from about 12 percent to about 8 percent of the atoll and the greatest loss being larger trees

(Nonner and Woodward, 2006).

Ants have been implicated in the increase of scale numbers because of a facultative relation in 

which they consume honeydew produced by scale and thus tend scale (Way, 1963). Pilot studies testing 

methods for ant control by using techniques tried in Australia began at Palmyra Atoll in 2004 (U.S. Fish 

and Wildlife Service, 2004). The FWS reported success in suppressing ant numbers and saw 

precipitous declines in ant populations on treatment islands (Nonner, 2005, in Nonner and Woodward, 

2006; Freeman, 2006c, in Nonner and Woodward, 2006). They also reported no decline in scale 

densities when ant eradiation occurred. At the same time, researchers examined leaves to measure 

parasitism rates by Hymenopteran wasps, Coccophagus ceroplastae and Metaphycus flavus, known to 

be scale parasitoids present at Palmyra Atoll. Once ants declined as a result of treatment, the 

researchers indicated there was no increase in parasitism of scale and suggested that ants do not play a 

critical role in limiting wasp parasitism. This was consistent with observations previously reporting that 

parasitoids may not be effective at high scale densities (Freeman, 2006c, in Nonner and Woodward, 

2006). These ant trials were only attempted on two islets, however, and full reports were unavailable.

Consequently, there remains some uncertainty regarding results and many questions about how the 

treatments might be replicated. The results are of particular interest in determining how the successful 

reduction or eradication of several nonnative invasive ant species may benefit other species and 

processes in the long term; however, it has been suggested that the amount of bait required for these 

treatments, and the difficulty in keeping nontarget species from the bait, might make this technique 

prohibitively expensive and difficult (A. Wegmann, University of Hawai`i, oral commun., 2008). These 

ants do not penetrate intact natural habitats (Wetterer, 2007). A recent study found that Pisonia grandis

monocultures showed clear limitation of ant distribution and suggested it is the quality as well as 

quantity of carbohydrate supply this plant harbors that may be limiting invasive spread of this ant 

species (Hoffman and Kay, 2009). The study suggests that an increase in larger healthy stands of 

Pisonia grandis may be the best defense against this particular ant species.
16

In 2005, the scale insect began to decrease atoll-wide, and an increase in the numbers of Pisonia 

grandis was recorded. By 2006, an increase in canopy cover was observed, although Nonner and 

Woodward (2006) considered that it was possibly due to reallocation of resources from root to shoot 

growth. By 2007, Pisonia grandis was considered to be in recovery with only patches of high scale 

densities remaining (Nonner, 2008). The FWS has shown a correlation between scale and tree health, 

but other contributing factors may have been involved, such as something causing an initial weakening 

of the trees making them more vulnerable to scale.

In 2007, the FWS began to investigate imidicloprid (an insecticide for the control of sucking 

insects) uptake in Pisonia grandis leaves and the longevity of treated leaves in infected trees compared 

to leaves of untreated infected trees and uninfected trees. In addition, the FWS tested whether 

imidicloprid would be effective in killing scale on individual trees or curbing spread from scale 

“hotspots” to nearby uninfected areas (Nonner, 2008). This trial was only applied at one location over a 

short time period during an apparent overall decline in scale numbers, however, so it is difficult to infer 

general results, and full reports were unavailable. The last census or systematic assessment was 

conducted in 2007 making quantitative analysis impossible. Recent (2008) qualitative examination 

revealed continued general recovery of Pisonia grandis, including regrowth. Chlorosis was evident in 

some areas (the southern complex of islets and was apparent in some of all tree species encountered), 

and other Pisonia grandis trees still had some patches of relatively high scale density (McEachern and 

Hathaway, 2008; W. Smith, U.S. Fish and Wildlife Service, oral commun., 2008).

Greenslade (2008) reviewed the decline of Pisonia grandis across its range, which began in the 

1990s and was attributed to scale outbreaks. Control measures, including systemic insecticides (for 

example, imidicloprid), poisoning ants, and biocontrols [for example, releasing predatory invertebrates 

such as lady bird beetles (Cryptolaemus montrouzieri)] were used to ameliorate the scale outbreak in 

some of these areas, yet scale numbers fell within months even in control areas, suggesting that pest 

decline was a natural phenomenon. Greenslade (2008) cautioned against using methods of biocontrol in 

the event of additional pest outbreaks. While biocontrols have been successful and beneficial in some 

circumstances, they have had unpredictable and damaging effects in other cases (as found citing Kuris, 

2003, and references therein).

Greenslade’s (2008) evaluation emphasizes the importance of developing regionwide 

collaboration and coordination in management and monitoring of resources. The Pisonia grandis

declines occurred over widely separated areas subject to different abiotic and biotic influences, 

suggesting that the declines were likely due to a widely occurring phenomenon such as climate 

variability. Greenslade (2008) suggests that stresses due to climate variability—such as rising sea 

surface temperatures, increased frequency and depth of El Niño events, and increased drought—may 

have been directly responsible for changes in freshwater availability for the trees. Likewise, cascading 

effects could have resulted from lower prey availability for sea birds, which would in turn reduce the 

availability of nutrients to Pisonia grandis. Greenslade (2008) emphasizes the importance of risk 

assessments, taking into consideration the total fauna, as well as considering that if the pest outbreak is 

due to climate variability it might not be desirable to use biocontrols but to let the system reach its own 

equilibrium. Much remains unknown regarding Pisonia grandis declines globally, management for this 

species worldwide, and specifically management at Palmyra Atoll. The varied scenarios above illustrate 

the value of conducting assessments to evaluate broader phenomena that can be relevant to local, 

regional, and global systems.

At Palmyra Atoll, these dramatic Pisonia grandis declines have impacts that resonate throughout 

the ecosystem. Relevant to these declines are natural history characteristics. As trees within Pisonia

grandis stands fall, they leave gaps. In response to a recent storm event that broke branches and toppled 
17

trees, Herbst (1992) noted that trees reproduce vegetatively and under suitable conditions will recover 

within a decade, reaching maximum height in two or three decades. There appears to be a similar 

response after scale declines. However, in addition to these kinds of events reducing Pisonia grandis

health and distribution, other pressures may reduce Pisonia grandis recovery. It was particularly noted 

during the recent decline that Pisonia grandis have been competing heavily with coconut palms to 

dominate newly opened areas. It is hypothesized that the invasive coconut palm does not provide 

habitat for guano-producing sea birds to roost and nest. This circumstance may further facilitate 

invasion by coconut palms, a species perhaps better equipped to take advantage of nutrient-poor soils 

than native plant species (H. Young, Stanford University, oral commun., 2008).

Coastal Strand Forest or Scaevola-Tournefortia

Native beach naupaka and tree heliotrope are the dominant species of the coastal strand 

vegetation type. Beach naupaka is more dominant on lagoon borders, and tree heliotrope dominates on 

the ocean edges (Herbst, 1992). Both are considered widespread, halophytic, pioneer species, and they 

can be found in monotypic stands or codominant as well as in mixed forest (Niering, 1963; Kepler and 

Kepler, 1994). They are generally not dense enough to prohibit ground cover and appear to have no 

substrate preference (Fosberg, 1953). This vegetation type, specifically tree heliotrope, is heavily used 

by red-footed boobies for roosting and nesting and is comparable to Pisonia grandis in native bird use 

overall (Young and others, 2010a). Tree heliotrope is less abundant across the Pacific than it was 

formerly (Kepler and Kepler, 1994). Kepler and Kepler (1994) report that most mature tree heliotrope

occur at the tree heliotrope -Pisonia grandis interface but die off as Pisonia grandis expands. Geckos 

have been observed drinking the nectar from tree heliotrope flowers (S. Hathaway and R. Fisher, U.S. 

Geological Survey, oral commun., 2007), and Rock (1916) reported that crabs feed on the flowers. 

Fosberg (1953) noted that bristle-thighed curlews (Numenius tahitiensis) transport the seeds of beach

naupaka, and Herbst (1992) noted that beach naupaka is the dominant species on Barren Islet with only 

a few coconut palms and tree heliotrope present, suggesting that it represents a very early successional 

stage. Usinger and La Rivers (1953) reported that both beach naupaka and tree heliotrope at Arno Atoll 

have their own insect species fauna.

Pandanus fischerianus

As observed by Fosberg (1953) elsewhere, though not common or large in extent, small groves 

of dense native Pandanus fischerianus are scattered throughout Palmyra Atoll. There were records or 

collections of Pandanus fischerianus from 20 islets in 2006.

Lepturus repens var. palmyrensis

One of the other native but minor vegetation types occurring at Palmyra Atoll includes small 

patches of native grassland. This grassland is composed of Palmyra Atoll’s only endemic species,

Lepturus repens var. palmyrensis (Herbst, 1992). It is closely related to taxa found on Malden and 

Christmas Islands as well as Pokak and Wake Atolls (from Herbst, 1992).

Coconut Palm Forest

The possibly nonnative coconut palm is likely the result of early introduction by Polynesian

explorers to Palmyra Atoll. There was subsequent expansion through plantings occurring prior to and 

during military occupation and continuing to at least 1957 (Dawson, 1959). While this species could 

have arrived on its own, it is very clear that its distribution has been increased with human help. In 

addition, the coconut palm has displayed invasive behavior, increasing from about 9,600 coconut palms 
18

in 1886 to about two million currently (Rock, 1916; A. Wegmann, University of Hawai`i, oral 

commun., 2008). Coconut palm forest is now the dominant forest type at Palmyra Atoll. It rapidly 

colonizes canopy gaps opened in other forest types (Herbst, 1992; Freeman, 2006a), and ongoing 

research by Hillary Young of Stanford University indicates that coconut palms may outcompete native 

species for nutrients. In addition, Young has found that the large nuts and fronds cause physical damage 

to native species when they fall, allowing for further expansion of established coconut palm groves.

Data collected recently regarding coconut palm use as habitat by native animal species are still 

being analyzed; however, it seems clear that few birds use coconut palms for roosting and even fewer 

for nesting (Young and others, 2010a). It is clear that the coconut palm forest provides abundant food 

and habitat for nonnative black rats (Rattus rattus), and the fruits are used as a food source by coconut 

crabs (A. Wegmann, University of Hawai`i, oral commun., 2008). Data collected for all crab species 

are pending (A. Wegmann, University of Hawai`i, oral commun., 2008), and data collection for geckos 

(R. Fisher and S. Hathaway, U.S. Geological Survey, oral commun., 2008) must continue in order to 

draw any conclusions about trophic interactions within the coconut palm groves (A. Wegmann, 

University of Hawai`i; R. Fisher and S. Hathaway, U.S. Geological Survey; H. Young, Stanford 

University, oral commun., 2008). As yet, there are no habitat assessments for other terrestrial species, 

but use of coconut palm by other invertebrate species in addition to crabs may be of interest. The 

abundant evidence of elevated seed predation of native seeds in coconut palm -dominated sites relative 

to other forest types further suggests significant cascading effects of coconut palm forest dominance 

throughout the larger Palmyra Atoll system (H. Young, Stanford University, oral commun., 2008).

Terminalia catappa

The history of tropical almond (Terminalia catappa) at Palmyra Atoll is unknown, but it is 

generally regarded as a nonnative invasive species. Dawson (1959) described tropical almond and other 

species as being purposely introduced through original plantings on Menge Islet. It is the dominant tree 

in several groves on Cooper Islet, particularly near the TNC camp, but it apparently has not yet spread 

in large numbers to other islets. Tropical almond should be considered for control plans similar to the 

plans suggested for coconut palms. At minimum it should be monitored to examine how quickly it is 

expanding in distribution.

Hibiscus tiliaceus

The history of hau (Hibiscus tiliaceus) at Palmyra Atoll is also unknown, but it is also regarded 

by some as a nonnative invasive species. Dawson (1959) describes this and other species as being 

purposely introduced through original plantings on Menge Islet. Small, very dense, monotypic hau 

groves are scattered on several islets in the atoll. In addition, there is a nearly impenetrable hau swamp 

in the central portion of Pelican Islet and another smaller hau swamp on Home Islet. The rate of spread 

of hau is unknown; expansion should be monitored and control plans considered.

Miscellaneous Species

In addition to the aforementioned vascular plants, two species of terrestrial algae, three mosses, 

eight lichens, and four fungi species have been identified at Palmyra Atoll (Rock, 1916; Dawson, 1959; 

Herbst, 1992).
19

Vegetation Monitoring

Aside from the Pisonia grandis censusing, quantitative vegetation surveys were completed only 

once at Palmyra Atoll, and the methods used may no longer be repeatable because of the difficulty in 

relocating the original points (Depkin, 2002). In 2007 Hillary Young (Stanford University), however, 

began multiple investigations on Palmyra Atoll, including an effort to identify changes in plant 

communities. Young’s work can be expanded upon for baseline data collection and to establish shortand long-term vegetation monitoring.

With the implementation of management actions planned for Palmyra Atoll, including 

eradication of introduced black rats and the control of coconut palms, there are likely to be significant 

impacts on the vegetation. These actions are inevitably going to cause changes in the ecosystem, 

presenting challenges and opportunities for conservation and recovery. The challenges of managing a 

rapidly changing ecosystem in response to management actions and potential responses to factors such 

as climate change, present the opportunity to learn through observing responses in the floral and faunal 

community and investigating management effectiveness. There is a local and global need for the 

qualitative and quantitative monitoring of resources at Palmyra Atoll to learn how such changes impact 

the ecosystem.

Fauna

Streets (1877), Rock (1916), and Dawson (1959) provide some early descriptions of the fauna 

inhabiting the terrestrial ecosystem at Palmyra Atoll. As with plants, the species lists have been built 

upon over time. There are no terrestrial mammals native to Palmyra Atoll, but there are various native 

birds, lizards, arthropods, and crabs, as well as several nonnative vertebrate and invertebrate species that 

have been inventoried through the years.

Mammals

As mentioned, there are no terrestrial mammals native to Palmyra Atoll, but several mammals 

have been introduced over time intentionally and unintentionally (table 4). It is unknown when or what 

the first nonnative mammal introductions were, but the most detrimental has undoubtedly been the black 

rat which will be discussed further (see Invasive Species). Flint and others (1992) reported pigs (Sus 

domestica) and a dog (Canis familiaris). Other nonnative mammals have included cats (Felis catus). 

At present (2010), two domestic cats and one domestic dog are cared for by TNC and restricted to 

Cooper, Menge, and Strawn Islets. Feral cats continue to be sighted periodically (S. Hathaway and R. 

Fisher, U.S. Geological Survey, oral commun., 2007; W. Smith, U.S. Fish and Wildlife Service; H. 

Young, Stanford University, oral commun., 2008).

Avifauna

Palmyra Atoll National Wildlife Refuge is the only site left for Pisonia grandis-dependent sea

birds within the Northern Line Islands (Flint, 1999). Sea birds are marine foragers and travel long 

distances (for example, red-footed boobies can exceed 200 km per day [Young and others, 2010c]),

returning to Palmyra Atoll to rest and breed. The terrestrial habitats on Palmyra Atoll support 10

species of breeding sea birds considered resident species and 4 others considered rare visitants (Fefer, 

1987; A. Wegmann, University of Hawai`i, oral commun., 2008; table 5). In addition to their important 

role of dispersing seeds, sea birds are important drivers in the ecosystem, bringing marine-derived 

nutrients in and producing copious guano. To a lesser extent, sea birds provide nutrients used 

throughout the food chain, in the form of feathers, regurgitated fish, and bird, chick, and egg carcasses.
20

The distribution, population, status and trends, ecology, and conservation concerns for these sea 

bird species can be found in the “Regional Seabird Conservation Plan, Pacific Region” (U.S. Fish and 

Wildlife Service, 2005). The greatest threats to sea birds at Palmyra Atoll locally to globally include 

introduced black rats and other invasive species, fishery interactions, contaminants, marine debris, and 

climate change. In fact, it is believed that black rats may be responsible for the current lack of burrownesting sea bird species on Palmyra Atoll. Species such as wedge-tailed shearwaters (Puffinus 

pacificus), Audubon’s shearwaters (Puffinus lherminieri), and Polynesian storm-petrels (Nesofregetta 

fuliginosa) have been observed offshore (Depkin, 2002; J. Smith, University of Washington; M.

McKown, University of North Carolina; E. Flint, U.S. Fish and Wildlife Service; L. Balance, National 

Oceanic and Atmospheric Administration; R. Pitman, National Oceanic and Atmospheric 

Administration, oral commun., 2008) or collected on the atoll (that is, Smithsonian Institute; USNM 

496523; petrel specimen from 2008, Matthew McKown) in the past, but we found no records of 

residence on the atoll.

Palmyra Atoll also supports overwintering populations of shore birds including bristle-thighed 

curlews, Pacific golden plovers (Pluvialis fulva), wandering tattlers, (Heterscelus incanus), and ruddy 

turnstones (Arenaria interpres). The bristle-thighed curlew and Pacific golden plover are designated by 

the FWS shore bird conservation plans as species of high conservation concern in national and regional 

shorebird plans, including the “U.S. Pacific Islands Regional Shorebird Conservation Plan” (Engilis and 

Naughton, 2004). They are also designated Birds of Conservation Concern by the FWS at the regional 

and national scale (U.S. Fish and Wildlife Service, 2002) because of limited breeding and nonbreeding 

distributions, low relative abundance, and a decline in populations. Both of these species overwinter on 

Palmyra Atoll, with some individual juvenile birds present throughout the year.

There are currently no records of breeding land birds on Palmyra Atoll. Two nonnative bird 

species are known to have been introduced to Palmyra Atoll. The crested mynah (Acridotheres 

cristatellus) has been reported as an introduced but now extirpated species at Palmyra Atoll (R.B. 

Clapp, U.S. Geological Survey, written commun., 1966, in Fefer, 1987). Domestic chickens (Gallus 

gallus) were also reported (Flint and others, 1992) but are no longer present.

Herpetofauna

There are six terrestrial herpetofauna species recorded from Palmyra Atoll (table 6). These 

include an undescribed native gecko species of Lepidodactylus n. sp., the potentially nonnative 

mourning gecko (Lepidodactylus lugubris) (a parthenogenic species represented on the atoll by many 

different clone types, of which there may be native and nonnative clone types), and an introduced house 

gecko (Hemidactylus frenatus). The house gecko is suspected of transferring parasites to at least the 

mourning gecko (R. Fisher and S. Hathaway, U.S. Geological Survey, oral commun., 2007). Current 

studies are underway to investigate the distribution and habitat use of all three gecko species to gather 

baseline information and consider nonnative species eradication (Fisher and Hathaway, 2007). One 

nonnative amphibian, the marine toad (Bufo marinus), was historically present on Palmyra Atoll but has 

not been observed since 2002 (S. Barclay, U.S. Fish and Wildlife Service, oral commun., 2008).

Two species of sea turtles, the federally endangered hawksbill (Eretmochelys imbricata) and 

threatened green turtles (Chelonia mydas), are found at Palmyra Atoll with green turtles being the more 

common species (Fefer, 1987; E. Sterling, American Museum of Natural History, oral commun., 2008). 

Both species of sea turtles are known to forage at Palmyra Atoll, and nesting has been documented at 

least twice for green turtles (Fefer, 1987; Depkin, 2002). Scientists from the FWS, American Museum 

of Natural History, and recently USGS have conducted surveys targeting species abundance and 

distribution in the eastern lagoons where sea turtles are most prevalent. Green turtles typically nest on 
21

sandy beach habitats but may be prevented from nesting and laying eggs at Palmyra Atoll. One 

hypothesis for the lack of nesting may be the extreme abundance of coconut palms close to the beach 

where green sea turtles might otherwise attempt to dig nesting pits (Suchanek and others, 2007). This 

hypothesis could be tested experimentally by developing a study design and monitoring program in 

conjunction with the proposed coconut palm control design (app. 1) targeting areas of sandy beach. Sea 

turtle hatchlings are vulnerable to rat predation (Caut and others, 2008); therefore, the success of this 

management action may hinge on black rat eradication.

Terrestrial Invertebrates

Arthropods

Palmyra Atoll supports a few native and many accidentally introduced nonnative insects

(Handler and others, 2007) (table 7). Little is known about the native species and their distributions and 

abundance across the atoll. The most detrimental nonnative insects include several ant species, a 

species of scale, and mealy bugs. The most extensive distribution data available include the presence of 

scale recorded during Pisonia grandis censuses and an informal survey of the distribution of whiteflies, 

scale, mealy bugs, and aphids. In the latter survey, it was found that only 9 percent of plant species 

surveyed were uninfested, and most observed plants harbored white fly (67 percent). In addition, 40

percent of plant species harbored mealy bugs, 28 percent harbored scale, and 18 percent harbored 

aphids (Freeman, 2006a). Recently, additional studies have been undertaken to collect more data on the 

distribution and abundance of insects in general; however, these data have not yet been analyzed (H. 

Young, Stanford University, oral commun., 2008).

Palmyra Atoll also supports six species of native terrestrial crabs, including the coconut crab

(Birgus latro), two species of land hermit crabs, two species of land crabs, and the brown tree climbing 

crab (Geograpsus crinipes) (table 8). These crabs play an important role in reducing organic matter and

mixing soils, as well as dispersing seeds (Wiens, 1962; A. Wegmann, University of Hawai`i, oral 

commun., 2008). Niering (1963) found that crab occurrence at Kapingamarangi and Caroline Islands 

correlated with soil friability and surface debris rather than with any vegetation type and found more 

burrows lagoonward. The existing data for all terrestrial crab species found at Palmyra Atoll are 

limited, but there is a slightly larger body of information for the coconut crab compared to the other crab 

species. 

The coconut crab, considered the largest terrestrial arthropod, is distributed across the IndoPacific (Reyne, 1939; Lavery and others, 1996). Over the past several years, populations have declined

because of overharvesting and (or) habitat modification or destruction in many regions, and the coconut 

crab has become regionally extinct from Mauritius (Wells and others, 1983). Although progress toward 

sustainable use has been made in several countries, this species maintains an International Union for 

Conservation of Nature (IUCN) listing of “Data Deficient,” and information on natural populations 

remains sparse (Eldredge, 1996). There is little known about this species globally and even less locally. 

Palmyra Atoll is an uninhabited national wildlife refuge where coconut crab harvesting is prohibited,

making it an ideal location to study the natural variation in coconut crab populations and responses to 

ecosystem changes, as well as the intentional or unintentional impact of management actions.

The coconut crab digs shallow burrows for mating and molting and frequently maintains several 

burrows within a territory. The species is omnivorous and will scavenge carcasses, climb trees to access 

food or escape, and can live to over 40 years. Because it is highly sought after for human consumption,

it is rare on all inhabited islands and considered an imperiled species. Rock (1916, p.16) noted that the 
22

coconut crab “abounds in great numbers” and went on to note that the species eats their “brother crab.” 

At present, the coconut crab is the least abundant crab at Palmyra Atoll (Howald and others, 2004).

Limited quantitative data from four islets indicate variability in coconut crab densities at 

Palmyra Atoll (Howald and others, 2004). Qualitative differences in coconut crab numbers around the 

atoll indicate that only a few islets currently support relatively large numbers of crabs. This variability 

may be mediated directly by the nonnative black rat. The black rat currently occupies Palmyra Atoll,

and there is extensive literature regarding the negative impacts of these mammals on Pacific Islands 

(Towns and others, 2006). Rats and coconut crabs are omnivorous, and rats may compete with coconut 

crabs for resources. Coconut crabs may also modify their activity patterns from nocturnal to diurnal as a 

result of rat presence. It is unknown to what extent coconut crabs are impacted by rats at Palmyra Atoll,

but evidence of predation (coconut crab carapace pieces in rat husking stations) has been observed (A. 

Wegmann, University of Hawai`i; R. Fisher, U.S. Geological Survey, oral commun., 2008).

There are two species of land hermit crabs present on Palmyra Atoll. The most abundant crab 

species is the strawberry hermit crab, followed by the purple hermit crab (Coenobita brevimanus) 

(Howald and others, 2004). These crabs use a gastropod shell (or other covering) to protect their 

unarmored abdomen and retain water to prevent desiccation. Both crabs are omnivorous scavengers and 

are generally nocturnal; however, they are active diurnally in humid regions such as Palmyra Atoll. 

Rock (1916) reported “multitudes” of hermit crabs climbing the trees and eating tree heliotrope flowers, 

as well as eating conspecifics.

There are two species of land crab, the orange land crab and the purple land crab (Cardisoma 

rotundum) on Palmyra Atoll. These species construct well-defined, deep burrows in soft soils and go 

below the water table to keep the lower portions of their burrows moist. They are primarily herbivorous 

but will also scavenge.

Though no additional information could be located, the brown tree climbing crab has also been 

recorded at Palmyra Atoll.

Most terrestrial crabs are crepuscular or nocturnal to avoid desiccation; however, the

aforementioned species have been observed to test the limits to consume easily available food (A. 

Wegmann, University of Hawai`i, oral commun., 2008). In collaboration with Island Conservation, A. 

Wegmann’s crab movement data from Palmyra Atoll showed no relation between crab numbers and 

proximity to vegetation or water, suggesting that observed daytime preference for particular habitats 

decreases when crabs are more active at night (A. Wegmann, University of Hawai`i, oral commun., 

2008). Wegmann also conducted an atoll-wide crab density survey for five species, surveying 5 percent

of the emergent land area across the major habitat types. He found strawberry hermit crabs to be the 

most abundant crab species on Palmyra Atoll, no preference across vegetation types for any crab 

species, and that there was a general avoidance of open areas (Howald and others, 2004).

We know little about what might be affecting crab populations at Palmyra Atoll. Potential 

limiting factors include predation, competition for shells of sizes used by juveniles of Birgus and all life 

stages of Coenobita species, and burrow damage. Rats may also cause a reduction in crab populations 

because of predation and competition.

Streets (1877) reported other invertebrate species such as a bird eye leech and a land snail 

(Tornatellina). Though both have been observed recently the leech remains unidentified.

Environmental and Human-caused Drivers and Stressors

Numerous environmental and human-caused drivers have affected Palmyra Atoll in the past and 

may continue to affect ecosystems into the present. Some of the most prominent environmental 

stressors include impacts from climate change, such as increased storm frequency and intensity, sea 
23

level rise, and potential seawater intrusion into groundwater. Direct hazards from current and past 

human impacts include those which originated during military use, such as contaminants, scraping, 

dredge fill and debris, marine debris of various origins, and introduction of invasive species. 

Considering the relative and interacting impacts of these stressors, it is necessary to identify priority 

management needs in an ecosystem-based management approach.

Storms

While we may not know long-term patterns of the recurrence of large storms, they have been 

recorded as occurring in 1958, 1992, 2002, 2005, and 2007 (Dawson, 1959; Flint and others, 1992; 

Herbst, 1992; Brainard and others, 2005; TNC staff, Palmyra Program, oral commun., 2008). Dawson 

(1959) reported extensive damage to the islets from a severe storm in 1958 which resulted in nearly a 

meter of water washing over the atoll, collapsing buildings, washing away parts of islets, killing 

introduced plant species, and generally sparing only those species resistant to typhoons. According to 

National Oceanic and Atmospheric Administration (NOAA) records (in Brainard and others, 2005),

three cyclones have been observed passing through the Exclusive Economic Zone of Palmyra Atoll in 

the past 60 years. One cyclone (Ekeka), recorded in 1992, registered as a Category One hurricane on 

the Saffir-Simpson Scale and reached wind speeds of over 100 km/hr. Flint and others (1992) and 

Herbst (1992) reported extensive damage to the atoll with the worst damage occurring in the Pisonia 

grandis forest where limbs were broken off and entire trees were blown down. In addition to felling 

trees, overland washes from storms can kill or thin coastal strand areas of beach naupaka and tree 

heliotrope. Though they found bird mortality difficult to quantify, Flint and others (1992) found bird 

carcasses pinned under trunks and limbs. Recent large storm events have also been capable of the 

removal of dredge fill and expansion of gaps between the islets, opening and enlarging channels 

between them. In some cases, storms have caused the outright disappearance of small “created” islets, 

and enlarging of islets has also been observed (Dawson, 1959; Collen and others, 2009; R. Fisher, U.S. 

Geological Survey, oral commun., 2008). Among other changes, these recent storm events have 

resulted in observed succession of Phymatosorus scolopendria ferns colonizing exposed highly organic 

soils within a few years. Even minor storms and winds can fell mature Pisonia grandis trees, creating 

small gaps within large contiguous “old growth” forests. Overall, the frequency and effects of these 

storms are unknown, but in recent years smaller wave events resulting from distant tropical and 

extratropical storms have occurred with greater regularity.

Climate Change

Changes in current patterns of precipitation and temperature are likely to alter community 

composition and ecosystem function as native species reach their physiological limits, food and other 

habitat resources become scarce, or competition from nonnatives increases. It is likely that tropical 

storms will become more intense in the future, with the higher windspeeds and heavier precipitation 

associated with ongoing increases of tropical sea surface temperatures (Intergovernmental Panel on 

Climate Change, 2007). Projection of the magnitude of sea level rise from thermal expansion of water 

and the melting of land-based ice sheets is less certain, but increases in sea level may affect low-lying 

equatorial islands and atolls within the next century. Sea level increase will likely speed shoreline 

erosion and will possibly result in complete inundation of Palmyra Atoll. No studies have been 

completed regarding the effects of climate change on the presence of subsurface freshwater aquifers or 

saltwater intrusion, although these phenomena have been noted throughout the Pacific (Shea and others,

2001).
24

Direct Human Impacts

Military use in the 1940s resulted in unprecedented change to Palmyra Atoll. Unexploded 

ordnance and additional contaminants still remain (Environmental Chemical Corporation, 1998; 

Woodward, 2000, 2001; Brainard, 2005). Contaminant assessments and removal efforts were made 

following military occupation of Palmyra Atoll and prior to its transfer to the FWS refuge system. 

More recently, preliminary surveys (Woodward, 2000, 2001; Depkin, 2002; Suchanek and others, 2007) 

conducted broadly across the atoll determined that contaminant sources are still present. These sources 

are composed of chemical and physical agents that may threaten ecosystem integrity. There has been 

some atoll-wide mapping of known and potential sources of contamination, and there is a continued 

effort to update the source list to prioritize cleanup, develop management strategies, and implement 

remediation (D. Papoulias, U.S. Geological Survey, oral commun., 2008).

Many of the contaminant concerns are currently related to avifaunal populations, but further 

research into contaminant presence at Palmyra Atoll and the impacts of contaminants on native species 

is necessary. Finkelstein and others (2007) found correlations between high levels of organochlorines 

and elevated levels of mercury and impaired immune function in black-footed albatrosses. In addition, 

shore birds may ingest soil while foraging, and soil can constitute up to 30 percent of the material a bird 

consumes (Beyer and others, 1994; Hui and Beyer, 1998). If the soil is contaminated, this consumption 

results in the direct intake of toxic substances by foraging birds.

Marine debris is a global problem. It can be seen at Palmyra Atoll in various forms, including

shoes, glass bottles, fishing nets, buoys, various plastics, and so on. Marine debris can have immediate 

negative impacts on animals because of entanglement and drowning, as well as injury and obstruction to 

the digestive tract (Spear and others, 1995; Henderson, 2001). Smaller items made of plastic can be 

ingested at sea by adult sea birds and subsequently fed to chicks, causing injury or mortality (Fry and 

others, 1987). Other studies indicate that ingestion of plastics may result in the assimilation of PCBs 

and other toxic chemicals (Ryan and others, 1988). There may be intermittent efforts to collect and 

dispose of marine debris at Palmyra Atoll, but no explicit protocol is currently in place.

Minimal urban footprint occurs presently, and it is restricted to Cooper and Menge Islets. The 

current (2010) use of Palmyra Atoll, however, includes vehicular activity, such as aircraft, trucks, 

tractors, backhoes, rollers, and a water tanker. The potential impacts of these vehicles may result in 

direct and indirect risks to terrestrial flora and fauna, including directly striking or crushing, potential 

crashes, and fuel spills. The main infrastructure at Palmyra Atoll includes 16 cabins, a galley, a row of 

three connected and several individual shipping container boxes used as refrigeration and storage rooms, 

a showerhouse, a restroom facility, a laboratory, offices, water catchment systems, a generator room, a 

dive locker, and a maintenance garage. This infrastructure supports up to 24 people at any given time. 

Other human activities in the terrestrial forest ecosystem include recreation, such as hiking, interpretive 

walks, research, and management actions.

The light and noise generated by human habitation and activity are of concern, as they may

disorient various species and potentially cause injury or mortality. Sea birds may become disoriented

and collide with lighted buildings or other nearby obstacles particularly during rain events. Turtle 

hatchlings could become disoriented and travel inland. There are management actions in place to 

reduce these impacts, including avoiding birds on nests where possible, minimizing the use of lights at 

night, and turning off lights during rain events at night when sea birds are most likely to become 

disoriented. Other protocols are in place to avoid bird airstrikes, which include actively keeping birds 

off the runway by approaching them and the use of loud sounds.
25

Invasive Species

Nonnative and even native species have the potential to be invasive, defined by Executive Order

No. 13112 as a species whose introduction has caused harm or may cause harm to environmental or 

human health (National Invasive Species Council, 2008). Invasive species are well known to be 

important factors in the decline of unique natural communities, species, and ecological processes inside 

and outside refuge boundaries (Vitousek, 1990; numerous papers in Veitch and Clout, 2002; Engilis and 

Naughton, 2004). Palmyra Atoll is home to various nonnative and invasive species, including plants,

arthropods, and black rats. 

The first invasive species to reach Palmyra Atoll are unknown but likely arrived with early 

movement through the area by Polynesians more than 1,500 years ago. It is widely believed, though not 

proven, that the first introduction of coconut palms happened in this way, and it is clear that additional 

plantings were made over the years (Rock, 1916; Dawson, 1959). The coconut palm now covers the 

majority of Palmyra Atoll, often in monotypic stands and at the expense of native species. There are 

several other invasive plant species, including koa haole (Leucaena leucocephala) and pothos 

(Epipremnum pinnatum), warranting investigation and prioritization for control and eradication (see 

Hathaway and Fisher, 2010).

Various species of nonnative arthropods including scale, mealy bugs, ants, mud daubers, and 

mosquitoes are all present on Palmyra Atoll, and their effects are poorly understood. There are 10 

species of nonnative ants recorded from Palmyra Atoll (Handler and others, 2007), 3 of which are 

considered highly invasive—the big-headed, crazy, and ghost ants (Pheidole megacephala, 

Paratrechina longicornis, and Tapinoma melanocephalum, respectively) (Pacific Invasive Ant Group, 

2004). It has been hypothesized that scale infestations exacerbated by tending ant species are

responsible for the massive recent decline of Pisonia grandis (Handler and others, 2007). The bigheaded ant is considered the most detrimental ant at Palmyra Atoll because of its association with scale; 

however, studies by Nonner and Woodward (2006) indicate that this may not be the case, at least at 

Palmyra Atoll. In addition, this species is known to displace most native invertebrate fauna through 

aggression (Wetterer, 2007). There is also a decrease in the abundance of vertebrates where the bigheaded ant is extremely abundant, and they can facilitate the invasion of introduced plant species.

Wasps and mosquitoes are also problems on Palmyra Atoll. Mosquitoes are of particular 

concern because they are potential vectors for various human and wildlife diseases. Two of the 

mosquito species, recently identified by Handler and others (2007), are clearly threats. The forest day 

mosquito (Aedes albopictus) has a wide host range including humans and birds and is a known potential 

carrier of dengue and West Nile virus (Kyle and Harris, 2008). The southern house mosquito (Culex 

quinquefasciatus) is a potential vector for avian diseases including avian malaria, avian pox, and West 

Nile virus (van Riper III and others, 2002; Ladeau and others, 2008).

Rats are well known to have severe effects on the ecosystems they invade, and there is extensive 

literature on the negative impacts of these mammals on Pacific Islands (for example, numerous papers 

in Veitch and Clout, 2002; Engilis and Naughton, 2004; Howald, 2004; Buckelew, 2005; U.S. Fish and 

Wildlife Service, 2005; Jones and others, 2008; Towns and others, 2009). They are thought to be 

responsible for the lack of burrowing nesters breeding on Palmyra Atoll, such as shearwater and petrel

species that are often observed offshore (Depkin, 2002; J. Smith, University of Washington; M.

McKown, University of North Carolina; E. Flint, U.S. Fish and Wildlife Service; L. Balance, National 

Oceanic and Atmospheric Administration; R. Pitman, National Oceanic and Atmospheric 

Administration, oral commun., 2008). They are also observed to be avid predators of ground nesting 

breeders at Palmyra Atoll, particularly sooty terns (Onychoprion fuscatus) (Fefer, 1987; A. Wegmann, 

University of Hawai`i; H. Young, Stanford University, oral commun., 2008). While nesting events have 
26

rarely been documented at Palmyra Atoll for green turtles, it is worth mentioning that rats have been 

documented killing and consuming sea turtle hatchlings elsewhere (Caut and others, 2008). Further, 

black rats at Palmyra Atoll have been observed attacking land hermit crabs, and land crab carapace 

pieces are common items in rat husking stations (A. Wegmann, University of Hawai`i, oral commun.;

R. Fisher, U.S. Geological Survey, oral commun., 2008). It is also thought that rats reduce native plant 

species by consuming seeds and seedlings (Grant-Hoffman and others, 2010). Rat and crab seed and 

seedling predation experiments indicate that rats kill and disperse seeds where they will not germinate,

whereas crabs manipulate seeds but do not kill them and disperse seeds randomly (A. Wegmann, 

University of Hawai`i, oral commun., 2008). Rats are also known to carry parasites, and recent studies 

have found that the parasites accompanying rats to Palmyra Atoll may use geckos as paratenic hosts (R. 

Fisher, U.S. Geological Survey, oral commun., 2008). The most consistent factor associated with 

abundance of these rat parasites (in rats) was found to be habitat provided by another potentially 

nonnative species, coconut palm (Lafferty and others, 2010). Fallen coconuts eaten by rats have also 

been shown to provide breeding habitat for mosquitoes elsewhere (Riviere and others, 1998).

TNC, in conjunction with the U.S. Department of Agriculture’s Wildlife Services and the FWS,

initiated rat eradication on Palmyra Atoll in 2001. This eradication program was an attempt to restore 

Palmyra Atoll’s terrestrial ecosystem. It was suspended in August 2003 after it became apparent that 

rats would not be eradicated from Palmyra Atoll through the methods in use and that the program 

needed to be reviewed and revised. In the spring of 2004, Island Conservation and TNC secured 

funding to conduct a site assessment on Palmyra Atoll and develop specific recommendations, 

techniques, and options to complete the rat eradication. In August 2004, a team of people with 

experience in island rodent eradication or control visited Palmyra Atoll to gather enough information for

trial eradication and to begin planning the successful eradication of rats from Palmyra Atoll (Howald 

and others, 2004; Buckelew and others, 2005). Radio telemetry data comparing movements of rats livetrapped in coconut palms with rats trapped on the ground revealed that rats on Palmyra Atoll regularly 

move between the tree canopy and the ground. The ranging or planar movements of rats captured on 

Palmyra Atoll were particularly small, leading researchers to believe that rats did not encounter or only 

infrequently encountered bait stations spaced at 50-m intervals. The rat eradication program is an 

example of adaptive management already taking place at Palmyra Atoll. Rat removal was attempted, 

but it failed. Experiments were conducted to improve methods, and the resulting information will be 

used to determine why rat removal failed and to improve future plans. Planning is now underway to 

continue the removal program by using new evidence to increase success.

Other nonnative animal species include house geckos, which also may be responsible for 

transmitting parasites and outcompeting native geckos. These geckos are currently centered around the 

urban core on buildings, and new poison baits being developed in New Zealand might be appropriate for 

attempting removal experiments.

The prevention of nonnative species invasion, as well as eradication plans, are covered in greater 

detail in the “Biosecurity Plan for Palmyra Atoll” (Hathaway and Fisher, 2010).

Conceptual Models of Palmyra Atoll Terrestrial Forest Ecosystems

Conceptual models provide a vehicle for summarizing existing knowledge and making 

hypotheses about the components of a system and their interactions. These models assist in identifying 

resources of concern and limiting factors. In turn, this clarification allows identification of potential 

management and monitoring objectives, helps identify critical assumptions and uncertainties remaining 

to be resolved, and may help determine what management actions are most appropriate and effective for 

achieving management goals. The conceptual model for the terrestrial Pisonia grandis forest ecosystem 
27

presented here is based on the best available information and expert opinion and is being used to 

develop testable management hypotheses for conserving and restoring the forests. As with many 

aspects of adaptive management, these models are designed with the expectation of modification based 

on new information. As management and monitoring implementation proceeds, these models can be 

improved.

Components of the Terrestrial Ecosystem on Palmyra Atoll

Components of the terrestrial forest ecosystem include the physical environmental factors 

(precipitation, temperature, soil moisture and nutrients, and possibly groundwater) necessary to support 

the native Pisonia grandis forest, coastal strand forest, and grassland habitat mentioned in previous 

sections. These terrestrial forests in turn provide important habitat for the native fauna to rest, avoid 

predators, reproduce, and forage. This system includes bottom-up and top-down drivers of the flow of 

energy. For example, storms are major top-down drivers that reset the system through succession. Sea

birds are also major biological top-down drivers because they deposit nutrients derived from the marine 

system into the terrestrial ecosystem (Polis and Hurd, 1996). Ongoing sea bird studies show that this 

holds true at Palmyra Atoll (Young and others, 2010a). The nutrient deposition by sea birds is just one 

example of how the terrestrial and marine ecosystems are highly interconnected. Disturbances 

occurring in the marine environment, such as a reduction in sea bird at-sea foraging resources, are likely 

to impact the terrestrial environment. Bottom-up terrestrial ecosystem drivers include invasive plant 

species that may displace native plants and create new forest types, storms that may occur with 

increasing frequency and intensity through global climate change, or saltwater intrusion into 

groundwater with rising sea level.

Understanding the components and processes involved in terrestrial ecosystem function is

important to managing the ecosystem and facilitating management decisions. Upon implementation of 

management plans to eradicate black rats and control coconut palms, we hypothesize that there will be a 

change in ecosystem drivers that will lead to an increase in native forest. More native forest would lead

to an increase in sea bird activity and increased nutrient input, which will reduce competition among 

plants for nutrients. We expect that leaf litter will increase with native forest recovery, facilitating soil 

development and bringing about increases in the abundance of invertebrate detritivores and more 

effective nutrient cycling. Similarly, the presence of a soil-litter habitat layer will encourage bottom-up 

trophic interactions among invertebrates and their predators.

Resources of Concern

Resources of concern can be modeled as components of the system, existing in a current state 

but having other desired future conditions or targets for management. Resources of concern are 

described in FWS 620.1 as “all plant and (or) animal species, species groups, or communities 

specifically identified in refuge purpose(s), System mission, or international, national, regional, State, or 

ecosystem conservation plans or acts” (http://www.fws.gov/policy/620fw1.html, accessesed September 1, 

2009). For example, waterfowl and shore birds are a resource of concern on a refuge whose purpose is 

to protect “migrating waterfowl and shore birds.” The Federal or State threatened and endangered 

species on that refuge are also resources of concern under terms of the respective endangered species 

acts.

In accordance with the intent behind FWS 620.1, resources of concern identified in this 

“Terrestrial Forest Management Plan for Palmyra Atoll” were considered within the context of FWS 

and TNC purpose, mission, and priorities as cited below along with their source documents:
28

• “...to protect and preserve the natural character of fish, wildlife, plants, coral reef communities, 

and other resources associated with the tidal lands, submerged lands, and waters of Palmyra” 

(Palmyra Atoll National Wildlife Refuge was established [as stated in Secretary Order No. 

3224])

• “...to administer a national network of lands and waters for the conservation, management, and 

where appropriate, restoration of the fish, wildlife, and plant resources and their habitats within 

the United States for the benefit of present and future generations of Americans” (The mission of 

the National Wildlife Refuge System)

• “to preserve, protect, and restore Palmyra’s unique ecosystem while facilitating valuable and 

responsible research through collaborative partnerships” (TNC Palmyra Program mission)

• “protection and enhancement of wildlife habitat” (TNC Palmyra Program management 

priorities)

The terrestrial ecosystem components listed in table 9 were identified as plant resources of 

concern through discussions with the FWS, including Pisonia grandis forest, coastal strand forest, and 

grassland (and their constituent native species). Likewise, animal species of concern have been grouped 

according to nesting habitat for avifauna and general habitat preferences for all other species and are 

presented in table 9. The resources identified in this document were chosen on the basis of review of 

published and unpublished information about the resources of Palmyra Atoll and in consultation with 

TNC and former and current FWS staff, as well as members of the Palmyra Atoll Research Consortium 

and other scientists (table 10). For each resource of concern, the current state and limiting factors are 

presented on the basis of qualitative observation. These designations may be adjusted as management 

and monitoring activities provide more information in an adaptive management feedback framework 

(Atkinson and others, 2004). The target states for these resources have been identified on the basis of

reasonable desired future conditions, given what we know now about current conditions, ecological 

interactions, and discussion with the Palmyra Atoll land management agencies.

Critical Assumptions and Uncertainties

There is a level of uncertainty about causes of declines in ecosystem integrity and the 

appropriate management actions required to improve them. This uncertainty is caused by gaps in 

knowledge about the system. These gaps include knowledge of the historical range and distribution of 

many species on Palmyra Atoll, their specific habitat requirements, and the pressures that affect them.

There are also uncertainties about the relations between the various vegetation communities and the 

ecological processes and pressures that drive system dynamics. For example, the decline of Pisonia 

grandis is thought to be related in varying degrees to scale infestations facilitated by ants, storm 

overwash, potential decreases in groundwater availability or quality, waterborne or soilborne 

contaminants, a possible paucity or lack of ectomycorrhizal mycobionts, and invasive species 

competition for space and nutrients, especially coconut palm, which also causes physical damage and 

promotes predation on young vegetative shoots by rats and crabs. It is assumed that improving and

increasing habitat for native forest will have positive effects on other resources of concern. For 

example, we assume that if there are more native Pisonia grandis and tree heliotrope, there may be an 

increase in sea birds. Therefore, these uncertainties and assumptions do not prevent us from developing 

management actions to achieve desired future conditions. Rather, the uncertainties and assumptions are 

part of the management system, and they guide monitoring and management activities to reduce 

uncertainty about progress toward the target condition.
29

Conceptual Modeling

Pisonia grandis forest is a resource of concern, but Pisonia grandis forest restoration is an 

objective nested within the overall management goal of maintaining and restoring the terrestrial 

ecosystem integrity of Palmyra Atoll. As an example of the conceptual modeling approach, we present 

a state-transition conceptual model for restoration of the Pisonia grandis forest (fig. 2). This model 

greatly simplifies all of the components of the forest ecosystem by focusing on identifying vegetation 

states. We expect management activities such as removal of nonnative species to cause a shift toward 

native forest better able to sustain itself without management assistance. This transition can be 

facilitated with the addition of native propagules, although seeds and seedlings may need protection 

from native and nonnative predators to become established. There are additional factors not included 

such as whether nutrients or ectomycorrhizae, which may be integral to Pisonia grandis restoration 

management but are absent or deficient, should also be considered. We identify several ecosystem 

components that we can monitor to gage progress toward the recovery of ecosystem integrity.

Habitat, Goals, Objectives, and Strategies

Much of Palmyra Atoll is a national wildlife refuge, and the development of a comprehensive 

conservation plan (CCP) is currently underway. The goals and objectives developed and strategies to 

achieve them, as will be identified within this CCP, will ultimately serve as the guidance for operations 

at Palmyra Atoll National Wildlife Refuge. This “Terrestrial Forest Management Plan for Palmyra 

Atoll” may provide preliminary operational guidelines for TNC and serve as part of their effort in 

contributing toward the development of the Palmyra Atoll National Wildlife Refuge CCP. Finally, this 

plan with approval and collaboration could be used in the interim as a guide for TNC and the FWS 

management actions. Priority management goals and objectives were identified for this plan in 

collaboration with TNC (Palmyra Program director and deputy director) and the FWS (refuge manager) 

in 2008. Collective knowledge of the status of Palmyra Atoll terrestrial resources was considered over 

varying temporal and spatial scales of management issues while considering national wildlife refuge

legal mandates. Input from literature review and discussions with numerous research scientists have all 

been incorporated into defining the specific objectives and strategies for focused action discussed within 

this plan.

Palmyra Atoll represents a unique opportunity to advance our understanding of ecosystem 

science through adaptive management, monitoring, and research. Ideally, management, monitoring, and 

research will work hand-in-hand to improve decisions for protecting, conserving, and where possible 

restoring the biodiversity, biological integrity, and environmental health within the ecosystem. Any 

long-term management and monitoring program must begin with establishing baseline information to 

assess changes in ecosystem status over time and evaluate what management action may be necessary 

and the impacts and success of management. Over time more intensive research projects can focus on 

key uncertainties in the system to provide the necessary resolution for further management.

The most urgent issues concerning the Palmyra terrestrial ecosystem are nonnative invasive 

species. This “Terrestrial Forest Management Plan for Palmyra Atoll” addresses issues related to 

invasive species and other problems. Priority goals are established along with associated objectives and 

strategies. The overarching goal is to perpetuate and where possible restore terrestrial ecosystem 

integrity through the following techniques:
30

1. Habitat Management:

2.

Maintain and enhance habitat to the extent possible to sustain thriving 

Pisonia grandis forest, coastal strand forest, endemic grassland, and self-sustaining populations 

of sea birds and shore birds, coconut crabs, native lizards, and native insects.

Monitoring and Assessment:

3.

Acquire information on distribution and abundance as needed for 

conservation of each resource of concern by developing monitoring and assessment programs 

relevant to local, regional, and national needs.

Research:

4.

Gather new information to facilitate conservation of terrestrial forest resources. This 

information will pertain to the ecology of the terrestrial ecosystem.

Planning: Achieve regional cooperation for conservation by developing a process to facilitate 

planning among relevant agencies and by working toward integration of resource concerns with 

land management plans at local to global levels.

The aim of developing the goals, objectives, and strategies within this “Terrestrial Forest 

Management Plan for Palmyra Atoll” is to carry out on-the-ground conservation and management

activities. The strategies drafted here focus on population enhancement through maintenance and 

improvement of key ecosystem components. The general desired outcome is to protect and maintain all 

native ecosystems and the biological diversity of Palmyra Atoll and conserve all constituent native 

species with an emphasis on sea bird populations. This desire resulted in a single goal with multiple 

objectives: Habitat Goal 1 (HG1): Protect, maintain, and where possible restore terrestrial ecosystem 

integrity—the natural biological communities and their associated biodiversity, habitats, populations, 

ecological processes, and environmental health of Palmyra Atoll. This goal and related objectives and 

strategies to achieve these are described in the following section.
31

Goals and Objectives of the “Terrestrial Forest Management Plan for Palmyra 

Atoll”

Habitat Goal 1 (HG1) Protect, maintain, and where possible restore terrestrial ecosystem 

integrity—the natural biological communities and their associated biodiversity, habitats, 

populations, ecological processes, and environmental health of Palmyra Atoll.

To assist in achieving this goal, several major objectives have been identified and are listed 

below in no particular order.

Objective 1 (HG1-O1): Develop conceptual model(s).

Objective 2 (HG1-O2): Map historical islet boundaries.

Objective 3 (HG1-O3): Measure, classify, and map terrestrial vegetation.

Objective 4 (HG1-O4): Measure, classify, and map soils.

Objective 5 (HG1-O5): Measure, classify, and map groundwater.

Objective 6 (HG1-O6): Maintain existing Pisonia grandis stands and promote new growth

and expansion.

(HG1-O6a): Maintain large trees in Pisonia grandis stands that incurred extensive 

large-tree mortality during 2001–6.

(HG1-O6b): Promote regeneration of small trees in Pisonia grandis stands that

incurred moderate mortality during 2001–6.

(HG1-O6c): Implement a “no net loss” Pisonia grandis strategy.

Objective 7 (HG1-O7): Control coconut palm succession and incursion into Pisonia 

grandis stands that suffered moderate to extensive mortality during the scale infestation.

Objective 8 (HG1-O8): Create openings for native coastal shrubs to colonize monotypic 

stands of coconut palm.

Objective 9 (HG1-O9): Map contaminants.

Objective 10 (HG1-O10): Remediate contaminants in priority areas.

Objective 11 (HG1-O11): Evaluate potential short- and long-term impacts of climate change.

Objective 12 (HG1-O12): Maintain and increase genetic diversity.

Objective 13 (HG1-O13): Accelerate native forest restoration.

Objective 14 (HG1-O14): Reintroduce former native faunal species extirpated from 

Palmyra Atoll.
32

Management Goals, Objectives, and Strategies for the Palmyra Atoll Terrestrial 

Forest

Habitat Goal 1 (HG1): Protect, maintain, and where possible restore terrestrial ecosystem 

integrity—the natural biological communities and their associated biodiversity, habitats, populations, 

ecological processes, and environmental health of Palmyra Atoll.

Range of Natural Variation

A terrestrial ecosystem that falls within the range of natural variability will have spatial patterns 

consistent with the processes associated with ecological types, diverse habitat to maintain natural 

communities, and viable populations of the floral and faunal species native to the region. For every 

ecosystem, natural disturbance processes are driven by variables with measurable patterns of frequency, 

intensity, and spatial scale. These patterns of variability over time constitute the range of natural 

variation. Within the range of natural variation, healthy ecosystems absorb and recover from 

disturbances without drastic alteration of their inherent function. Range of variability here refers to the 

area in which plant and animal communities can naturally live and reproduce, referring to potential as 

opposed to current distributions. Natural communities are assemblages of plants and animals, fungi, 

and microorganisms associated with each other; their physical environments; and natural processes 

within a given area. Viable populations maintain sufficient size to persist over time despite natural 

stochastic processes. Ideally, terrestrial ecosystems maintain the given forest successional trajectories

despite stressors. The physical environment should be capable of sustaining reproducing populations of 

priority tree species, necessary for continued forest stability and development, which in turn provide 

habitat capable of sustaining reproducing populations of priority wildlife species. This plan aims to 

ensure ecosystem integrity and stability by managing for an ecosystem’s capacity for resistance and 

resilience. Many factors, including large storm events, play a role in natural disturbance processes and 

fall within the range of natural variation; however, other factors, including military modification and the 

introduction of invasive insects, may alter ecosystem structure and historical energy-flow pathways. 

Such factors could inhibit the ecosystem from returning to the desired equilibrium and cause it to depart 

even further from the desired future state.

Desired Future Conditions

The attributes of a restored ecosystem from the Society for Ecological Restoration International 

Science and Policy Working Group (2004) provide standards to measure success. These standards, 

modified as relevant to Palmyra Atoll, are listed below.

• The ecosystem contains a characteristic assemblage of indigenous plant and animal species that 

provides for a natural/historical community structure (for example, conserve sea bird populations 

and habitats). Restore conditions in which refuge ecosystems are fully capable of sustaining 

normal ecosystem functions and display or mimic all or in part the floral and faunal biodiversity 

and community structure that occurred before military modification. All functional groups of 

the ecosystem are represented or have the potential to colonize by natural means.

• Restore environmental health such that the physical environment supports and sustains 

reproducing populations of species essential for ecosystem stability and (or) development along 

the desired trajectory.
33

• Maintain and reinstate forest conditions in which the dynamic attributes that compose refuge 

ecosystems are expressed within “normal” ranges of variability and activity relative to their 

ecological stage of development, and signs of dysfunction are absent. The terrestrial ecosystem 

is resilient to normal periodic stress events. The forest ecosystem is suitably integrated into the 

landscape through abiotic and biotic flows and exchanges.

• Threats to restored habitat integrity are reduced or eliminated, and management opportunities are 

identified to deter vegetative phaseshifts and trophic cascades associated with invasive species 

and human-caused influences.

The FWS envisions a terrestrial ecosystem that is managed in parallel with other atoll 

management and restoration efforts. Late-seral “old growth” Pisonia grandis forest will predominate 

many of the areas where natural islets once occurred. In these “natural” areas, a highly resilient and 

steady-state native coastal strand community of beach naupaka and tree heliotrope will occupy many of 

the coastal edges, gaining only occasional footholds into the interior Pisonia grandis stands. Altered 

coconut palm succession and dominance will be curtailed beginning within areas where storms and 

heavy insect-related disturbance caused mortality of mature Pisonia grandis and where native coastal 

strand forest species are inhibited from establishing along coastal niches because of coconut palm

monocultures.

• Management can sustain and restore biological diversity by promoting habitat structure and 

composition within its historical bounds. Restoration of biological diversity may confer 

resilience to natural disturbances within the historical range of natural variability. Whether the 

restored system will be resilient to disturbance outside this range remains to be seen. Our 

expectation is that a restored system has the best chance of resilience to novel changes as well.

For each objective toward the goal of protecting, maintaining, and where possible restoring 

terrestrial ecosystem integrity, monitoring “objectives” must be incorporated. Adaptive management 

should take place such that management actions are set in the context of well-designed monitoring 

programs. Monitoring that is designed to show the effectiveness of management actions should be built 

into the “Terrestrial Forest Management Plan for Palmyra Atoll”. Monitoring results should be 

reviewed annually to provide feedback to management so that treatments can be adjusted if necessary to 

move toward achieving the target condition. A list of guidelines/objectives for monitoring the terrestrial 

ecosystem of Palmyra Atoll follows:

1. Balance traditional species-specific and site-specific inventory and monitoring efforts with 

collection of data in a broader, community-based, ecosystem context. 

a. Identify significant gaps in the science available to support an ecosystem monitoring 

approach. 

b. Anticipate the need for solutions to subtle and far-reaching problems in the future of 

cumulative and interactive ecological effects.

2. Ensure that an adaptive management strategy is incorporated into monitoring, monitoring studies, 

and research to assess and modify management strategies to achieve habitat objectives.
34

3. Promote the use of coordinated, standardized, cost-effective, scale-dependant, statistically sound 

and defensible sampling designs and methods for gathering, analyzing, and presenting 

qualitative and quantitative data. 

a. Identify and prioritize baseline status monitoring and effectiveness monitoring, as well as 

monitoring studies for each management strategy and alternative.

b. Identify research objectives that address key management questions or uncertainties.

Management actions are suggested that will affect different ecosystem components directly and 

indirectly and could produce unexpected results. For example, based on previous monitoring some 

suggested management actions are intended to promote native forest expansion and maintain and 

increase forest integrity. Monitoring design is an integral part of the planning and implementation of 

these actions. For instance, to document trends in forest stand composition, native plant recruitment,

and habitat structure (for native animals of concern) with time since management action (for example, 

coconut palm control, rat removal, other nonnative or invasive removal), baseline data must be collected 

within a monitoring design context. Baseline data collection is the first step in implementing 

monitoring, and it can be used to learn more about distribution and habitat requirements. Baseline data

are also essential in determining species status and in monitoring to assess management effects. This 

step should not be overlooked in the initial development and implementation of management strategies.

Objectives

(HG1-O1) Develop conceptual model(s).

Develop new and refine existing conceptual model(s) outlining ecosystem interconnections,

including ecosystem drivers; ecological stressors; the biological, physical, and chemical processes that 

are affected by these stressors; ecosystem values; and measurable attributes to evaluate the status of 

ecosystem values.

Conceptual models provide a vehicle for discussion and facilitate the process of summarizing 

existing knowledge and making hypotheses about the components of a system and their interactions. 

They assist in identifying resources of concern and their limiting factors. In turn, they assist in the

identification of potential management and monitoring objectives, help identify critical assumptions and 

uncertainties remaining to be resolved, and may help determine what management actions may be most 

appropriate and effective for achieving management goals. Multiple models can be developed and 

modified as necessary (for example, to portray hierarchically nested models representing different levels 

of complexity within the ecosystem at varying spatial and temporal scales), as well as to overcome the 

disadvantages of any one model type.

Rationale

• Create and refine driver-stressor model(s), state and transition model(s), and control model(s).

Strategy

• Conceptual modeling begins with identifying the goal of the model. Models should 

communicate general ecosystem characteristics and our understanding of system dynamics. For 

a driver-stressor model this leads to steps such as identifying and understanding drivers in the 

ecosystem. Drivers are sources of change that may be physical, biological, or chemical and may 

include natural (for example, storms) and human-caused (for example, introduced species) 
35

processes, while stressors are physical or chemical changes that can result from drivers and can 

create changes in abiotic and biotic components of the system. Models can include ecological 

interactions between drivers that in turn result in changes (abiotic and biotic), all of which may 

influence the condition, structure, integrity, stability, distribution, trajectory, and succession of in 

this case Pisonia grandis and other plant communities within the terrestrial forest ecosystem. 

Likewise, these factors are related back to the faunal components of the system, and all 

components feed back to ecosystem processes such as nutrient cycling and trophic relations. It 

is essential to evaluate the importance of ecosystem drivers and how they might be influenced to 

minimize any negative ecosystem impacts.

• State-transition models can be used as a management tool illustrating hypotheses about how 

transitions may occur between states. An example of this is the highly simplified model for 

transitions between vegetation types shown in fig. 2 in response to disturbance such as from 

invasive species or management action to remove invasive species.

• Control models can be used to evaluate process feedback and mechanisms. For example, a 

control model can be used to summarize the current understanding of feedback and mechanisms 

that exist between many components: plant communities, nutrients, consumers, decomposers, 

humus, and water availability and may include how drivers such as climate change or invasive 

species may affect the system as well as how these all interlink.

(HG1-O2) Map historical islet boundaries.

Use historical maps (for example, Collen and others, 2009) to produce a map of islet boundaries

for the period before military modification.

The military scraped islets and used dredge material to connect existing islets. Military 

personnel also created causeways for increased movement, as well as 10 additional islets of varying 

sizes, 6 of which still exist. These military modifications have had large effects on the Palmyra Atoll 

ecosystems including the following:

Rationale

• changes in land area (doubled), volume (tripled), and connectivity.

• changes in substrate.

• changes in surface elevation.

• changes in groundwater.

• changes in lagoon flow dynamics.

• changes in species distribution and potentially species composition.

The impacts of these changes to the terrestrial ecosystem are largely unknown, and identifying 

original boundaries can be used to assess at least some of the potential effects. In addition, there have 

been reports that the increased connectivity between islets has negatively impacted lagoon flow and 

sedimentation (Dawson, 1959; Maragos, 1993). There is evidence that ecosystem processes appear to 

be reverting Palmyra Atoll islets back to their natural boundaries, a factor which is important in 

prioritizing restoration sites (Collen and others, 2009). Finally, future management actions attempting 

to facilitate reversal of military modifications will undoubtedly have impacts to the current state of the 

terrestrial ecosystem.
36

• Collaborate with University of Victoria scientists (see Collen and others, 2009) to compare 

historical islet configuration data (converted to Geographic Information System [GIS]) to current 

boundaries.

Strategy

(HG1-O3) Measure, classify, and map terrestrial vegetation.

Spatially quantify current terrestrial vegetation (for example, Pisonia grandis forest extent, 

distribution, state, size class, succession) and the deviation of current terrestrial forest habitats from 

2001–2 (early scale outbreak) conditions. Update or replace Wegmann (2005) vegetation maps by 

using classification with remotely sensed data and repeat Nonner and Woodward (2006) Pisonia 

grandis size-class inventory. Consider paleoecology to identify currently unrepresented species.

Developing terrestrial vegetation data within a GIS framework will be important in establishing 

priorities for habitat management goals and objectives, identifying restoration or remediation strategies, 

developing monitoring and research plans, and prioritizing projects. These data may include 

identification of where and to what extent changes have occurred and correlation with other variables to 

make hypotheses about the causes of vegetation changes, potential problems, evaluating succession, 

nonnative species distribution, canopy cover, and so on.

Rationale

Design and conduct forest surveys consistent with long-term monitoring. Examine the range of 

variation in current plant species abundance, community composition and structure, plant diversity, 

litter, and substrate cover. (Some of the major vegetation types include stands dominated by coconut 

palm, Pisonia grandis, beach naupaka, tree heliotrope, tropical almond, hau, Pandanus fischerianus,

Phymatosorus scolopendria, and Lepturus repens.)

Strategy

• Relate environmental factors (for example, hydrology, soil type and components, land use, 

proximity to strand, proximity to landing points) to major plant communities mapped by 

Wegmann (2005) and described by Freeman (2006a).

• Describe locations and map distribution of rare and sensitive plants (beginning with Depkin, 

2002, and Freeman, 2006a, b).

• Conduct vegetation classification and mapping.

• Conduct spatial analyses. Vegetation maps can be combined with maps of other biotic and 

abiotic resources making them useful tools for understanding interactions. Combining different 

maps can reveal correlations and underlying relations. They can be evaluated spatially and 

temporally for patterns and trends in native and nonnative species distributions. This 

information can be used to track and study spatially explicit effects of natural disturbances, 

management actions, and resource changes over time and make predictions about changes in the 

future.

(HG1-O4) Measure, classify, and map soils.

Spatially quantify soil properties and patterns relative to vegetation associations and terrestrial

fauna use.
37

Developing soil data within a GIS framework and characterizing variables related to ecosystem 

processes such as physical and chemical properties (for example, soil moisture, depth, nutrients) will be 

important in establishing priorities for habitat management goals and objectives, identification of 

restoration or remediation strategies, developing monitoring and research plans, and prioritization of 

projects. Some potential management issues include soil quality for soil fauna and terrestrial plants and 

potential competition for soil nutrients between coconut palms and other plants. Understanding 

variability is necessary in determining the response of the soil resources to management actions, 

specifically the removal of coconut palms, increasing forest diversity, and restoration of lagoon 

circulation.

Rationale

• Prior to beginning relevant restoration activities, assess the best techniques for conducting 

surveys to determine baseline soil conditions and parameters of interest.

Strategy

• Conduct soil classification and mapping.

• Correlate soil properties with resources of concern to investigate underlying relations and 

prioritize potential restoration sites.

• Conduct toxicity studies of the soil to assess contaminant levels, as various chemicals might 

interact with or inhibit restoration goals.

(HG1-O5) Measure, classify, and map groundwater.

Spatially quantify groundwater properties relative to vegetation associations and terrestrial fauna 

use. 

Developing groundwater data within a GIS framework will be important in establishing 

priorities for habitat management goals and objectives, identification of restoration or remediation 

strategies, developing monitoring and research plans, and prioritization of projects. Some potential 

management issues include groundwater availability to terrestrial plants, groundwater quality, and 

potential competition for groundwater between coconut palms and other plants, particularly native 

seedlings trying to establish. Understanding groundwater variability is necessary in determining the 

response of the groundwater resources to management actions, specifically the removal of coconut 

palms, increasing forest diversity, and restoration of lagoon circulation.

Rationale

• Prior to beginning relevant restoration activities, assess the best techniques for conducting 

surveys to determine baseline groundwater conditions. Various tools exist to determine 

groundwater extent on atolls. These tools include monitoring wells, seismic profiling, and fiberoptic distributed temperature sensing (Ward, 1990). Long-term monitoring could be achieved 

through remote monitoring across seasons to determine the effect of rainfall on the depth and 

extent of freshwater lenses.

Strategy

• Conduct toxicity studies of the groundwater to assess contaminant levels, as various chemicals 

might interact with or inhibit restoration goals.

• Determine the location, extent, and quantity of the groundwater resources on Palmyra Atoll, if 

present. Identify the vertical and lateral extent of any fresh groundwater lens.
38

• Assess the groundwater quality in relation to maximum salinity for biotic use and human-caused 

contamination.

• Determine the age of groundwater and the basic hydrology of Palmyra Atoll.

• Install groundwater monitoring stations on multiple islets (for example, disturbed, natural, and 

humanmade) to record and log water quantity and quality for a hydrologic model. 

(HG1-O6) Maintain existing Pisonia grandis stands and promote new growth and expansion.

(HG1-O6a) Maintain large trees in Pisonia grandis stands that incurred extensive large-tree 

mortality during 2001–6.

Ensure that Pisonia grandis stands lose no more than 15 percent of their largest diameter 

trees and no more than 10 percent of their mid-diameter trees to scale outbreaks over the next

20 years.

(HG1-O6b) Promote regeneration of small trees in Pisonia grandis stands that incurred 

moderate mortality during 2001–6.

Ensure establishment of small trees within stands in or near gaps created by the death of

large canopy trees.

(HG1-O6c) Implement a “no net loss” Pisonia grandis strategy.

Maintain or restore Pisonia grandis so that the numbers of stands and numbers of 

individuals atoll-wide are equal to levels documented in the FWS early scale outbreak 

monitoring beginning in 2004 (Nonner and Woodward, 2006).

To ensure that Pisonia grandis stands persist into perpetuity, it is important to protect and where 

possible restore not only mature stands but also stands with a high percentage of smaller diameter trees

that can grow into canopy gaps when they are created. Therefore, to ensure that late-seral stage stands 

continue to exist, it is important to maintain larger trees until they can be replaced over time. “No net 

loss” here means protecting not only mature trees but also younger stands and smaller diameter trees

within the forest. This protection will allow younger trees to mature and replace larger diameter trees in 

the future. Pisonia grandis stands have often been described as monotypic; managing stands that 

largely consist of Pisonia grandis by number and cover facilitates natural succession back to this 

original state. Understanding the species composition, diameter distribution, and other species 

information allows us to develop a comprehensive strategic management plan to meet this objective. 

Various diameter trees are important for the health and longevity of the forest and provide a diversity of 

functions and structures for use by forest constituents.

Rationale

• In the absence of detailed historical stand information, use existing maps of vegetation types 

(Wegmann, 2005) and initial Pisonia grandis census information (Nonner and Woodward, 2006) 

to determine baseline conditions.

Strategy

• Identify priority areas for management and restoration.

• Coconut palm control—Develop and implement a program to reduce cover/density of coconut 

palms (see app. 1) (a) on islets where there are mixed stands of coconut palm and Pisonia 

grandis and (b) where coconut palms are present as monotypic stands.
39

• Plant Pisonia grandis seedlings, saplings, or cuttings and encourage growth of existing Pisonia 

grandis in coconut palm control areas.

• Encourage Pisonia grandis growth in canopy gaps created by falling Pisonia grandis trees.

• Develop and implement a program to prevent coconut palm spread to islets without coconut 

palms after removal efforts.

• Evaluate conditions across sites, comparing stand health with site parameters to assess potential 

problems such as nutrient deficiencies and potential ectomycorrhizal requirements (that is, 

determine presence and distribution to assess areas possibly lacking or containing a paucity of 

mycobionts).

• Evaluate effectiveness of recent Pisonia grandis management strategies at Palmyra Atoll and 

elsewhere (that is, imidicloprid injection, biocontrol using Cryptolaemus montrouzieri coupled 

with ant control) aimed at removing scale infestations to prevent further spread and increase 

forest health. 

• Develop collaborations globally to share and develop management, monitoring, and research 

protocols and results and develop alerts for early warning signs.

We do not know what size Pisonia grandis trees made up the various seral stages at pre-scaleinfestation locations or the natural variation in abundance over time. Likewise we do not know the 

prevalence of other native species in mixed stands dominated by Pisonia grandis. The natural ability of 

forests to restore themselves is unclear, and management actions may be necessary (for example, 

determine whether nutrient deficiency is a problem and if it can be solved by fertilizer application; 

determine if ectomycorrhizae are an integral part of forest health at Palmyra Atoll and if they are present 

in sufficient numbers at restoration sites or should be harvested from other sites and added to soil). If 

active restoration is determined necessary, examine the best means to propagate and outplant native 

plants and trees, determine whether genetic consideration is necessary, identify priority locations for 

forest restoration, actively propagate and outplant native plants, apply soil amendments where 

necessary, and monitor success.

Uncertainties

(HG1-O7) Control coconut palm succession and incursion into Pisonia grandis stands that 

have suffered moderate to extensive mortality during the scale infestation.

Reduce coconut palms to 0 percent cover within 50 m of the peripheral edge of all mid-seral and 

late-seral Pisonia grandis stands. Also, remove all coconut palms from existing gaps and eliminate 

them as they occur in new gaps.

The general consensus seems to be that coconut palms have the capacity to invade Palmyra Atoll 

forests, changing nutrient cycling processes and water regimes and altering habitats for animals. There 

are multiple documented plantings of these trees (Rock, 1916; Dawson, 1959), and their numbers have 

increased from several thousand to about two million since first documented. Palmyra Atoll scientists 

observe that the coconut palm may have a competitive advantage over Pisonia grandis through 

competition for water, direct and indirect alteration of soil nutrients, physical damage from nut and 

frond fall, and shading. There is much discussion in the Palmyra Atoll files and literature about the role 

of coconut palms in island ecology (Young and others 2010a, b).

Rationale

Coconut palm saplings are currently evident in almost every Pisonia grandis gap. They are

generally taller than the Pisonia grandis specimens even when they are the same age. Therefore, 
40

coconut palms may be able to recolonize the Pisonia grandis tree-fall gaps, establishing a presence in 

the island interior where they were scarce before tree-fall. A prudent management action may involve

eradicating coconut palms in the gaps as soon as possible, and preferably before they become 

reproductive.

• Coconut palm control (see app. 1).

Strategy

(HG1-O8) Create openings for native coastal shrubs to colonize monotypic coconut palm 

stands.

Manage for native closed-canopy tree heliotrope and beach naupaka shrubs by reducing the 

current linear extent of coastal monotypic coconut palm stands (greater than 90 percent coconut palm 

cover for greater than 300 m along the coast) to 10 percent coconut palms by cover every other 100 m 

along the coast and 50 m from water within the next 3 years.

Native coastal shrub species are halophytic pioneers and though still widespread across their 

native range are not as abundant as they once were. Coastal strand species can play a role in reducing 

erosion, contributing to soil development and succession, and protecting other native species such as 

Pisonia grandis from salt spray and wind throw, as well as providing habitat for various native 

vertebrate and invertebrate species. Tree heliotrope is a preferred roosting and nesting species for sea 

birds. To ensure that native coastal shrub stands persist, it is important to not only protect and where 

possible restore existing stands but also increase their extent by reducing the areas taken over by 

coconut palms.

Rationale

• Coconut palm control—Develop and implement a program to reduce cover/density of coconut 

palms (see app. 1) (a) on islets where there are mixed stands of coconut palms and other trees 

and (b) where coconut palms are present as monotypic stands.

Strategy

• Develop and implement a program to prevent coconut palm spread to islets without coconut 

palms after removal efforts.

(HG1-O9) Map contaminants.

Spatially quantify contaminants on Palmyra Atoll.

After Palmyra Atoll was declared a Formerly Used Defense Site (R.M. Towill Corporation,

1993; Woodward, 2001) in 1992, investigation, planning, and remediation activities to locate, evaluate, 

and remove debris and contaminated materials occurred through 1998. Sites requiring remediation still 

remain, however, and these sites as well as additional sites should be investigated for potentially 

negative ecological effects. In addition, developing contaminant data within a GIS framework will be 

important in establishing priorities for habitat management goals and objectives, identification of 

restoration or remediation strategies, developing monitoring and research plans, and prioritization of 

projects. This information will aid in the conservation of resources on Palmyra Atoll by preventing or 

minimizing health effects due to exposure to Palmyra Atoll’s legacy contaminants

Rationale
41

In addition there are newly arriving contaminants such as those from marine debris and the 

potential for accidental spills from terrestrial and offshore activities. Marine debris not only can be

mechanically detrimental because of entanglement or internal damage from ingesting but also can 

harbor contaminants that can poison the organisms ingesting them.

• Continue surveys for contamination sources and develop a digitally geocoded GIS map of the 

known (potential) sources of contamination (KPSOCs) on Palmyra Atoll. Provide specific 

information on the location, type, and description of the KPSOCs.

Strategy

• Evaluate the ecological impacts of persistent and newly arriving contaminants.

(HG1-O10) Remediate contaminants in priority areas.

See rationale for HG1-O9.

Rationale

• Develop protocols for regularly collecting and appropriately disposing of marine debris.

Strategy 

• Other remediation activities will be developed on the basis of findings from HG1-O9. 

(HG1-O11) Evaluate potential short- and long-term impacts of climate change.

The impacts of climate change with regard to terrestrial habitats may include increased 

frequency and intensity of storms, and sea level rise that results in changing temperature and 

precipitation patterns, saltwater intrusion of groundwater, and outright inundation. Expected biological 

effects include significant changes to species distributions and ecosystem functions and increases in the 

range and impact of many forest invasive species and diseases.

Climate change has proximate and long-term effects on natural resources. Storms and droughts 

and temperature changes have the potential for direct and indirect negative effects. Gathering 

information regarding changes over time will be important for determining trend data locally. These

data could also act as a bellwether for nearby regions and internationally to develop response strategies 

to reduce potentially negative impacts where possible.

Rationale

• Identify appropriate weather monitoring stations; determine how many monitoring stations are 

necessary and where to deploy them. Set up a system for maintenance of the stations, as well as 

the data collection, processing, and dissemination.

Strategy

• Complete literature reviews for the design and development of a monitoring plan that integrates 

changes in weather with changes in other aspects of the system.

(HG1-O12) Maintain and increase genetic diversity.

Recognize and preserve the genetic variability of species associated with the terrestrial 

ecosystem.
42

Just as it is important to protect and restore nutrient cycling and other ecosystem processes, 

maintaining and where necessary restoring evolutionary processes are integral to the long-term viability 

of ecosystems. Genetic variability can increase species ability to withstand short-term abiotic and biotic 

disturbances such as outbreaks of pathogens and provides the potential for adaptive evolution in the face 

of longer term changes in the ecosystem such as that expected with climate change.

Rationale

• Identify genetic diversity at Palmyra Atoll and frame relations according to global diversity.

Strategy

• Evaluate practices that affect gene pools and biodiversity (for example, seed sources for 

reforestation). 

• Once a genetic framework is identified, set goals for maintaining or increasing genetic diversity.

(HG1-O13) Accelerate native forest restoration.

Pisonia grandis was once considered common on coral islands but has recently undergone 

considerable heavy disturbance from activities such as military use, phosphate mining, attempts to 

establish copra plantations, and invasive species introductions. It has been described as declining within 

its native range (Walker, 1991). While the above mentioned activities have ceased (with the exception 

of unintentional invasive species introductions), coconut palms have reached invasive species status and 

continue to proliferate, and rats consume seedlings and consume and disperse seeds where they will not 

germinate.

Rationale

Pisonia grandis and coastal strand forests not only are important in and of themselves but also 

are used by many faunal resources of concern, including sea birds, geckos, crabs, and other 

invertebrates. Sea birds, specifically tree nesters, use native forest as primary habitat for resting and 

breeding. Generally, they prefer Pisonia grandis and tree heliotrope. Crabs use the forest floor and 

largely avoid open areas. They forage on live and dead plant matter, seeds, seedlings, and decomposing 

plants and animals and use the cover for hiding. Native geckos are found on forest plants (with most 

data currently from forest margins and not a lot of information yet available from the forest interior). 

Current examinations of trophic structure are beginning to reveal important patterns indicating 

differences in food resources used by geckos in native forest versus coconut palm forests. Stomach 

content analyses are in progress (H. Young, Stanford University; R. Fisher, U.S. Geological Survey, 

oral commun., 2008). Additional insect surveys are planned (H. Young, Stanford University, oral 

commun., 2008). Combining these and additional surveys, as well as continued isotope work, will be 

beneficial in identifying important habitat and resources.

• Eradicate rats—Develop and approve study designs, monitoring programs, and implementation 

strategies.

Strategy

• Coconut palm control—Develop and implement a program to reduce cover/density of coconut 

palms (see app. 1).

• Identify locations for forest restoration.

• Evaluate conditions across sites by comparing stand health with site parameters to assess 

potential problems such as nutrient deficiencies and potential ectomycorrhizal requirements (that 

is, determine presence and distribution to assess areas potentially lacking or containing a paucity 

of mycobionts).
43

• Evaluate effectiveness of recent Pisonia grandis management strategies at Palmyra Atoll and 

elsewhere (that is, imidicloprid injection, biocontrol using Cryptolaemus montrouzieri coupled 

with ant control) aimed at removing scale infestations to prevent further spread and increase 

forest health. 

• Actively propagate and outplant native plants. 

• Develop collaborations globally to share and develop management, monitoring, and research 

protocols and results and develop alerts for early warning signs.

There is a general need to determine the best means to propagate and outplant native plants and 

trees (for example, transplants, seeds, cuttings, fertilizer, caging, ectomycorrhizal enhancement) and to 

determine whether genetically diverse plant stock is necessary.

Uncertainties

(HG1-O14) Reintroduce former native fauna species extirpated from Palmyra Atoll.

The terrestrial forest ecosystem may have once supported additional species that have been 

extirpated because of disturbance from activities such as military use, attempts to establish copra 

plantations, and invasive species introductions. Many of these locally extirpated species played an 

important role in ecosystem processes and are in decline in other parts of their range. Successful 

implementation of this objective requires initial management action, such as rat eradication, to eliminate 

threats to former native species.

Rationale

• Eradicate rats—Develop and approve study designs, monitoring programs, and implementation 

strategies.

Strategy

• Develop plans to attract or translocate species identified as extirpated (for example, shearwater 

and petrel species could be attracted with call playback).

Scope and Limitations of this “Terrestrial Forest Management Plan for Palmyra Atoll”

There are limitations to the scope of the “Terrestrial Forest Management Plan for Palmyra 

Atoll”. As mentioned above, this plan is not yet meant to be comprehensive. Additional literature 

review will undoubtedly uncover more information specific or relevant to management activities on 

Palmyra Atoll, and it should be recognized that this plan is still in the development process. As stated, 

the focus of this plan is to strategize on how to meet mutual goals of TNC and the FWS to conserve and 

protect resources. This plan was written in an attempt to be realistic about where research and 

management efforts should be initially focused and is not meant to indicate that other aspects are 

unimportant. Instead, this “Terrestrial Forest Management Plan for Palmyra Atoll” is an effort to tackle 

the highest priorities first. There is still a need to expand the current objectives and strategies and 

potentially even modify goals as deemed necessary through additional expert review. As such, this 

document will benefit from an adaptive management approach to subsequent updates to the plan, as 

efforts planned for the near term are refined and implemented.
44

Some of the key questions and recommendations associated with management actions are listed 

below.

1. Will forest management actions reverse past human-caused problems? To what degree and at 

what cost?

2. Will anticipated patterns and diversity of forest seral stages be resilient to the interaction of 

changing climate, insects, and disease in the long term?

3. How will the terrestrial forest ecosystem respond to coconut palm control?

4. Vegetation dynamics will change, and development of the plant monitoring design will be 

important.

5. How will the terrestrial forest ecosystem respond to black rat eradication?

6. Sea bird and shore bird populations may increase with management actions to improve Pisonia 

grandis forest (specifically, removing coconut palms and eradicating rats). It is recommended 

that researchers review Citta and others (2006) for monitoring guidance. Alternatively, sea bird 

and shore bird populations may not increase despite onsite terrestrial management actions. Sea 

birds forage offshore, and shore birds migrate from distant breeding sites. Concurrently 

developing collaborations toward monitoring and managing pressures outside the proximate 

terrestrial ecosystem will be necessary to successfully protect the birds utilizing and contributing 

to Palmyra Atoll terrestrial ecosystem integrity.

7. Other faunal communities may increase over the short or long term with management actions to 

improve Pisonia grandis forest by removing coconut palms and eradicating rats. Monitoring

plans have been under development, and some have already begun implementation (for example, 

H. Young, Stanford University; A. Wegmann, University of Hawai`i; J. Collen, Victoria 

University of Wellington, oral commun., 2008; E. Sterling, American Museum of Natural 

History; R. Fisher, S. Hathaway, K. McEachern, D. Papoulias and K. Hart, U.S. Geological 

Survey, and others). This information can inform planned management actions as well as assess 

impacts. It is recommended that researchers continue monitoring plan development and baseline 

data collection.
45

Potential Workplan

Phase 1

General

• Build teams relevant to the review, development, and implementation of monitoring and 

management planning.

• Continue drafting management planning documents.

• Continue drafting conceptual models.

• Continue developing strategies for objectives.

• Continue developing and implementing monitoring plans.

• Build data quality assurance, data management, analysis, and reporting strategies.

• Develop adaptive management feedback loop process.

• Implement approved pieces of plan.

 Examples

• Experimentally reduce/remove invasive and (or) competing species. For example, begin 

coconut palm control and management. Monitor for expected and unexpected ecosystem 

responses to threats and management prior to and subsequent to implementing management 

action.

• Continue efforts to design and implement rat eradication, including developing monitoring plans 

and collecting baseline information.

• Inventory resources and identify and model relations:

• What is the distribution and status of Pisonia grandis forest across Palmyra Atoll?

• What is the range of variation within the terrestrial ecosystem?

• With what specific habitat parameters are Pisonia grandis forest and other vegetation types 

associated (for example, soil quality, moisture availability, and so on)?

• What are the extent, distribution, and condition of those habitats?

• To what pressures is Pisonia grandis sensitive?

• What are the distribution, abundance, and habitat characteristics and trophic interactions of 

native sea birds? Geckos? Crabs? Insects?
46

Phase 2 

General

• Review Phase 1 and adapt as necessary.

Examples

Status and trends questions:

• Document trends in forest stand composition, native plant recruitment with time since coconut 

palm removal (repeat for rat removal). 

• Is the abundance of Pisonia grandis on Palmyra Atoll within baseline range of variation? If not, 

is it increasing or decreasing?

• Formulate questions to identify early warning of problems: Is the areal extent of Pisonia grandis

changing?

• What is the abundance or proportion of trees harboring scale—a pest considered to severely 

reduce tree health and potentially cause tree mortality?

• Targeted study questions: Which habitat restoration techniques result in a Pisonia grandis forest 

recovery success rate at or above a level sufficient to sustain populations?

• Continue implementation of rat eradication.

• Continue coconut palm control.
47

References Cited

Airy Shaw, H.K., 1952, On the distribution of Pisonia grandis R. Br. (Nyctaginaceae) with special 

reference to Malaysia: Kew Bulletin, v. 7, no. 1, p. 87–97.

Allaway, W.G., and Ashford, A.E., 1984, Nutrient input by seabirds to the forest on a coral island of the 

Great Barrier Reef: Marine Ecology – Progress Series, v. 19, no. 3, p. 297–298.

Aronson, Karen, and Anderson, Lisa, 2000, Archaeological monitoring of remedial action, Palmyra 

Atoll: Prepared by Ogden Environmental and Energy Services Co., Inc., 82 p.

Ashford, A.E., and Allaway, W.G., 1985, Transfer cells and hartig net in the root epidermis of the 

sheathing mycorrhiza of Pisonia grandis R. Br. from Seychelles: New Phytologist, v. 100, no. 4, p. 

595–612.

Atkinson, Andrea, Trenham, P.C., Fisher, R.N., Hathaway, S.A., Johnson, B.S., Torres, S.G., and 

Moore, Y.C., 2004, Designing monitoring programs in an adaptive management context for regional 

multiple species conservation plans: Sacramento, Calif., U.S. Geological Survey Western Ecological 

Research Center, U.S. Geological Survey Technical Report, 69 p.

Ayers, J.F., and Vacher, J.W., 1986, Hydrogeology of an atoll island—a conceptual model from detailed 

study of a Micronesian example: Ground Water, v. 24, no. 2, p. 185–198.

Bailey, R.T., Jenson, J.W., and Olsen, A.E., 2009, Numerical modeling of atoll island hydrogeology: 

Ground Water, v. 47, no. 2, p. 184–196.

Bell, H.L., 1969, Recent Papuan breeding records: Emu, v. 69, no. 53, p. 235–237.

Beyer, W.N., Connor, E.E., and Gerould, Sarah, 1994, Estimates of soil ingestion by wildlife: Journal of 

Wildlife Management, v. 58, no. 2, p. 375–382.

Brainard, Rusty, Maragos, Jim, Schroeder, Robert, Kenyon, Jean, Vroom, Peter, Godwin, Scott, Hoeke, 

Ronald, Aeby, Greta, Moffitt, Russell, Lammers, Marc, Gove, Jamison, Timmers, Molly, Holzwarth, 

Stephani, and Kolinski, Steve, 2005, The state of coral reef ecosystems of the U.S. Pacific remote 

island areas, in Waddell, J., ed., The state of coral reef ecosystems of the United States and Pacific 

Freely Associated States, NOAA Technical Memorandum NOS NCCOS 11. NOAA/NCCOS: Silver 

Spring, Md., Center for Coastal Monitoring and Assessment’s Biogeography Team, p. 338–372.

Buckelew, Stacey, Howald, G.R., Wegmann, Alex, Sheppard, Jacob, Curl, Jennifer, McClelland, Pete, 

Tershy, Bernie, Swift, Katie, Campbell, Earl, and Flint, Beth, 2005, Progress in Palmyra Atoll 

restoration—rat eradication trial, 2005: Santa Cruz, Calif., Island Conservation Report to U.S. Fish 

and Wildlife Service, 50 p.

Burger, A.E., 2005, Avian dispersal of Pisonia grandis, an Indo-Pacific tropical tree associated with 

seabird colonies: Journal of Tropical Ecology, v. 21, p. 263–271.

Carlquist, S., 1974, Island biology: New York, Columbia University Press, 656 p.

Caut, Stephane, Angulo, Elane, and Courchamp, Franck, 2008, Dietary shift of an invasive predator—

rats, seabirds and sea turtles: Journal of Applied Ecology, v. 45, no. 7, p. 428–437.

Chambers, S.M., Hitchcock, C.J., and Cairney, J.W.G., 2005, Ectomycorrhizal mycobionts on Pisonia 

grandis on coral cays in the Capricorn-Bunker group. Great Barrier Reef, Australia: Mycological 

Research, v. 109, no. 10, p. 1105–1111.

Christensen, N.L., Bartuska, Ann, Brown, J.H., Carpenter, Stephen, D’Antonio, Carla, Francis, Rober, 

Franklin, J.F., Mac Mahon, J.A., Noss, R.F., Parsons, D.J., Peterson, C.H., Turner, M.G., and 

Woodmansee, R.G., 1996, The report of the Ecological Society of America Committee on the 

scientific basis for ecosystem management: Ecological Applications, v. 6, no. 3, p. 665–691.

Christophersen, Erling, 1927, Vegetation of Pacific equatorial islands: Bishop Museum Bulletin, v. 44, 

no. 2, p. 1–79.
48

Citta, John, Reynolds, M.H., and Seavy, N.E., 2006, Seabird monitoring assessment for Hawai`i and the 

Pacific Islands: Prepared for the U.S. Fish and Wildlife Service, 122 p.

Collen, J.D., Garton, D.W., and Gardner J.P.A., 2009, Shoreline changes and sediment redistribution at 

Palmyra Atoll (Equatorial Pacific Ocean)—1874–Present: Journal of Coastal Research, v. 25, no. 3, p. 

711–722.

Dawson, E.Y., 1959, Changes in Palmyra Atoll and its vegetation through the activities of man, 1913–

1958: Pacific Naturalist, v. 1, no. 2, p. 1–51.

Department of the Interior Secretarial Order No. 3224, 18 January 2001, Palmyra Atoll National 

Wildlife Refuge, accessed September 1, 2009 at 

http://elips.doi.gov/app_so/act_getfiles.cfm?order_number=3224.

Depkin, C.D., 2002, Trip report to Palmyra Atoll, 06 August 2001–07 October 2002: Honolulu, 

Hawai`i, U.S. Fish and Wildlife Service, 133 p.

Eldredge, L.G., 1996, Birgus latro, in IUCN 2009, IUCN Red List of Threatened Species. Version 

2009.1., accessed September 1, 2009 at http://www.iucnredlist.org/apps/redlist/details/2811/0.)

Engilis, Jr., Andrew, and Naughton, Maura 2004, U.S. Pacific Islands regional shorebird conservation 

plan. U.S. Shorebird Conservation Plan: Portland, Oreg., U.S. Department of the Interior, Fish and 

Wildlife Service, 67 p.

Environmental Chemical Corporation, 1998, Draft closure report remedial action Palmyra Atoll, 

Palmyra USA. USACE Contract No. DACA83-95-D-0002. Prepared for the Department of the Army, 

U.S. Army Corps of Engineers Pacific Ocean Division, 406 p.

Falkland, Anthony, 2002, Tropical island hydrology and water resources—current knowledge and future 

needs, in Hydrology and water resources management in the humid tropics. Proceedings—Second 

International Colloquium, Panama, Republic of Panama, 22-26 March 1992. UNESCO-IHP-V 

technical documents in hydrology no. 52: Paris, UNESCO, p. 237–372.

Fefer, S.I., 1987, Trip report to Palmyra Atoll, 16–30 September 1987: Honolulu, Hawai`i, U.S. Fish 

and Wildlife Service Administrative Report, 31 p.

Finkelstein, M.E., Grasman, K.A., Croll, D.A., Tershy, B.R., Keitt, B.S., Jaman, W.M., and Smith, 

D.R., 2007, Contaminant-associated alteration of immune function in black-footed albatross 

(Phoebastria nigripes), a North Pacific predator: Environmental Toxicology and Chemistry, v. 26, no. 

9, p. 1896–1903.

Fisher, R.N., and Hathaway, S.A., 2007, Scientific scoping trip to Palmyra September 28–October 12, 

2007: Honolulu, Hawai`i, U.S. Fish and Wildlife Service Administrative Report, 5 p.

Flint, Elizabeth, 1999, Status of seabird populations and conservation in the tropical island Pacific, in

Eldredge, L.G., Maragos, J.E., Holthus, P.F., and Takeuchi, H.F., eds., Marine and coastal 

biodiversity in the tropical island Pacific region—population, development, and conservation 

priorities, v. 2: Honolulu, Hawai`i, East-West Center, p. 189–210.

Flint, Elizabeth, Herbst, Derral, McDermond, Ken, Woodside, David, and Yuen, Andy, 1992, Survey of 

the terrestrial biota of Palmyra Atoll 18 February to 9 March 1992: Honolulu, Hawai`i, U.S. Fish and 

Wildlife Service Administrative Report, 19 p.

Fosberg, F.R., 1953, Vegetation of central Pacific atolls: Atoll Research Bulletin, v. 23, p. 1–26.

Fosberg, F.R., 1954, Soils of the northern Marshall Atolls with special reference to the Jemo Series: Soil 

Science, v. 78, no. 2, p. 99–108.

Fosberg, F.R., 1957, Description and occurrence of atoll phosphate rock: American Journal of Science, 

v. 255, no. 8, p. 584–592.

Fosberg, F.R., 1994, Comments on atoll phosphate rock: Atoll Research Bulletin, v. 396, p. 1–5.
49

Freeman, Scott, 2006a, Vascular flora of Palmyra Atoll—an update to 1992: Honolulu, Hawai`i, U.S. 

Fish and Wildlife Service Administrative Report, 28 p.

Freeman, Scott, 2006b, Plants of Palmyra—an unofficial guide to the vascular flora of Palmyra Atoll:

Honolulu, Hawai`i, U.S. Fish and Wildlife Service Administrative Report, 86 p.

Freeman, Scott, 2006c, The Palmyra Pisonia report—February 2006 (draft): Honolulu, Hawai`i, U.S. 

Fish and Wildlife Service Administrative Report.

Fry, D.M., Fefer, S.I., and Sileo, Louis, 1987, Ingestion of plastic debris by Laysan albatrosses and 

wedge-tailed shearwaters in the Hawai`ian Islands: Marine Pollution Bulletin, v. 18, no. 6 part b, p. 

339–343.

Gerhing, Catherine, and Bennett, Alison, 2009, Fungal-plant-insect interactions—the importance of a 

community approach: Environmental Entomology, v. 38, no. 1, p. 93–102.

Grant-Hoffman, M.N., Mulder, C.P.H., and Bellingham, P.J., 2010, Effects of invasive rats and 

burrowing seabirds on seeds and seedlings on New Zealand islands: Oecologica, v. 162, no. 4, p. 

1005–1016.

Greenslade, Penelope, 2008, Climate variability, biological control and an insect pest outbreak on 

Australia’s Coral Sea islets: lessons for invertebrate conservation: Journal of Insect Conservation, v. 

12, no. 3–4, p. 333–342.

Gross, W.J., 1964, Water balance in anomuran land crabs on a dry atoll: Biological Bulletin, v. 126, no. 

1, p. 54–68. 

Handler, A.T., Gruner, D.S., Haines, W.P., Lange, M.W., and Kaneshiro, K.Y., 2007, Arthropod 

surveys on Palmyra Atoll, Line Islands, and insights into the decline of the native tree Pisonia grandis

(Nyctaginaceae): Pacific Science, v. 61, no. 4, p. 485–502.

Handler, A.T., and James, S.A., 2006, Anguilla marmorata (giant mottled eel) discovered in a new 

location—natural range expansion or recent human introduction?: Pacific Science, v. 60, no. 1 p. 109–

115.

Hathaway, S.A., and Fisher, R.N., 2010, Biosecurity plan for Palmyra Atoll: U.S. Geological Survey 

Open-File Report 2010–1097, 80 p.

Hatheway, W.H., 1955, The natural vegetation of Canton Island, an equatorial Pacific atoll: Atoll 

Research Bulletin, v. 43, p. 1–10.

Henderson, J.R., 2001, A pre- and post-MARPOL Annex V summary of Hawai`ian monk seal 

entanglements and marine debris accumulation in the northwestern Hawai`ian Islands, 1982–1998:

Marine Pollution Bulletin, v. 42, no. 7, p. 584–589.

Herbst, Derral, 1988, Flora and vegetation of Palmyra Atoll: Honolulu, Hawai`i, U.S. Fish and Wildlife 

Service Administrative Report, 37 p.

Herbst, Derral, 1992, Flora and vegetation of Palmyra Atoll: Honolulu, Hawai`i, U.S. Fish and Wildlife 

Service Administrative Report, 31 p.

Hoffman, B.D., and Kay, Alice, 2009, Pisonia grandis monocultures limit the spread of an invasive 

ant—a case of carbohydrate quality?: Biological Invasions, v. 11, no. 6, p. 1403–1410.

Howald, Gregg, Samaniego, Araceli, Buckelew, Stacey, McClelland, Pete, Keitt, Bradford, Wegmann, 

Alex, Pitt, W.C., Vice, D.S., Campbell, Earl, Swift, Katie, and Barclay, Steve, 2004, Palmyra Atoll rat 

eradication assessment—Trip report, August 2004: Santa Cruz, Calif., Island Conservation, Report to 

U.S. Fish and Wildlife Service, 61 p.

Hui, C.A., and Beyer, W.N., 1998, Sediment ingestion of two sympatric shorebird species: Science of 

the Total Environment, v. 224, no. 1–3, p. 227–233.
50

Intergovernmental Panel on Climate Change, 2007, Climate change 2007—the physical science basis. 

Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on 

Climate Change: Solomon, Susan, Qin, Dahe, Manning, Martin, Chen, Zhenlin, Marquis, Melinda, 

Averyt, K.B., Tignor, M.M.B., and Miller, H.L., eds., Cambridge, United Kingdom and New York, 

Cambridge University Press, 996 p.

Jones, H.P., Tershy, B.R., Zaveleta, E.S., Croll, D.A., Keitt, B.S., Finkelstein, M.E., and Howald, G.R.,

2008, Severity of the effects of invasive rats on seabirds—a global review: Conservation Biology, v. 

22, no. 1, p. 16–26.

Keating, B.H., 1992, Insular geology of the Line Islands, in Keating, B.H., and Bolton, B.R., eds., 

Geology and offshore mineral resources of the Central Pacific Basin. Circum-Pacific Council for 

Energy and Mineral Resources: Earth Sciences Series, p. 77–99.

Kepler, A.K., and Kepler, C.B., 1994, Part I. History, physiography, botany, and isle description: Atoll 

Research Bulletin, v. 397, p. 1–225.

Kuris, A.M., 2003, Did biological control cause extinction of the coconut moth, Levuana iridescens, in 

Fiji?: Biological Invasions, v. 5, no. 1–2, p. 133–141.

Kushlan, J.A., Steinkamp, M.J., Parsons, K.C., Capp, Jack, Acosta Cruz, Martin, Coulter, Malcolm,

Davidson, Ian, Dickson, Loney, Edelson, Naomi, Elliot, Richard, Erwin, R.M., Hatch, Scott, Kress, 

Stephen, Milko, Robert, Miller, Steve, Mills, Kyra, Paul, Richard, Phillips, Roberto, Saliva, J.E.,

Sydeman, Bill, Trapp, John, Wheeler, Jennifer and Wohl, Kent, 2002, Waterbird conservation for the 

Americas—the North American Waterbird Conservation Plan, version 1: Washington, D.C.,

Waterbird Conservation for the Americas, 78 p.

Kyle, J.L., and Harris, Eva, 2008, Global spread and persistence of dengue: Annual Review of 

Microbiology, v. 62, p. 71–92.

Ladeau, S.L., Marra, P.P., Kilpatrick, A.M., and Calder, C.A., 2008, West Nile Virus revisited—

consequences for North American ecology: BioScience, v. 58, no. 10, p. 937–946.

Lafferty, K.D., Hathaway, S.A., Wegmann, A.S., Shipley, F.S., Backlin, A.R., Helm, Joel, and Fisher, 

R.N., 2010, Stomach nematodes (Mastophorus muris) in rats (Rattus rattus) are associated with 

coconut (Cocos nucifera) habitat at Palmyra Atoll: Journal of Parasitology, v. 96, no. 1, p. 16–20.

Lafferty, K.D., and Kushner, David, 2008, Draft initial monitoring plan for Palmyra Atoll: Sacramento, 

Calif., U.S. Geological Survey, Western Ecological Research Center, 74 p.

Lavery, S., Moritz, Craig, and Fielder, D.R., 1996, Indo-Pacific population structure and evolutionary 

history of the coconut crab Birgus latro: Molecular Ecology, v. 5, no. 4, p. 557–570.

Lee, M.A.B., 1984, Biogeography and ecology of atoll plants: Progress in Physical Geography, v. 8, no. 

4, p. 509–522.

Maragos, J.E., 1993, Impact of coastal construction on coral-reefs in the United-States-affiliated Pacific 

islands, v. 21, no. 4, p. 235–269.

McEachern, Kathryn, and Hathaway, S.A., 2008, Trip report, Palmyra Atoll, May 21–28, 2008—

terrestrial ecology: Honolulu, Hawai`i, U.S. Fish and Wildlife Service Administrative Report, 5 p.

Mueller-Dombois, Dieter, and Fosberg. F.R., 1998, Vegetation of the tropical Pacific islands: New 

York, Springer-Verlag, 773 p.

National Invasive Species Council, 2008, 2008–2012 National Invasive Species Management Plan, 35 

p.

National Wildlife Refuge System Improvement Act of 1997, 1997, Public Law 105-57, accessed 

September 1, 2009 at http://www.fws.gov/refuges/policiesandbudget/HR1420_index.html

Niering, W.A., 1963, Terrestrial ecology of Kapingamarangi, Caroline Islands: Ecological Monographs, 

v. 33, no. 2, p. 131–160.
51

Nonner, Edith, 2005, FY05 forest health protection accomplishment report for Palmyra Atoll National 

Wildlife Refuge: Honolulu, Hawai`i, U.S. Fish and Wildlife Service Administrative Report.

Nonner, Edith., 2008, Scale population dynamics and control measures and the status of Pisonia grandis

at Palmyra Atoll NWR in 2007—presentation at the 89th annual meeting of the American Association 

for the Advancement of Science Pacific Division.

Nonner, Edith, and Woodward, Lee Ann, 2006, Draft. The decline of Pisonia grandis at Palmyra Atoll 

NWR—factors and solutions: Honolulu, Hawai`i, U.S. Fish and Wildlife Service Administrative 

Report, 28 p.

O’Grady, A.P., Eamus, Derek, Cook, P.O., and Lamontagne, Sebastien, 2006, Groundwater use by 

riparian vegetation in the wet-dry tropics of northern Australia: Australian Journal of Botany, v. 54, 

no. 2, p. 145–154.

Pacific Invasive Ant Group, 2004, Pacific ant prevention plan—a proposal prepared for the Pacific Plant 

Protection Organization and Regional Technical Meeting for Plant Protection, March 2004, 29 p.

Polis, G.A., and Hurd, S.D., 1996, Linking marine and terrestrial food webs—allochthonous input from 

the ocean supports high secondary productivity on small islands and coastal land communities: The 

American Naturalist, v. 147, no. 3, p. 396–423.

Reyne, A., 1939, On the food habits of the coconut crab (Birgus latro L.) with notes on its distribution: 

Archives Néerlandaises de Zoologie, v. 3, p. 282–320.

Rivière F., Klein, J.M., Thirel, R., and Chebret, M., 1998, Ecologie d'Aedes polynesiensis Marks, 1951 

(Diptera : Culicidae) vecteur de la filariose de Bancroft. I. - Les noix de coco rongées par les rats 

comme gîtes larvaires: Annales de la Société Entomologique de France, v. 34, no. 22, p. 195–207. 

R.M. Towill Corporation, 1993, Palmyra Atoll remediation plan Palmyra Atoll, Line Islands 160°, 06'

west longitude, 5°, 52' north latitude: Prepared for Department of the Army, United States Army 

Corps of Engineers Pacific Ocean Division, Fort Shafter, Oahu, Hawai`i, 558 p.

Rock, J.F., 1929, The voyage of the Luka to Palmyra Island: Atlantic Monthly, v. 144, no. 9, p. 560–

566.

Ryan, P.G., Connell, A.D., and Gardner, B.D., 1988, Plastic ingestion and PCBs in seabirds—is there a 

relationship?: Marine Pollution Bulletin, v. 18, no. 5, p. 217–219.

Sadler, J.C., 1959, A study of some recent climatological data of the Line Islands: Proceedings of the 

Ninth Pacific Science Congress of the Pacific Science Association, Department of Science, Bangkok, 

Thailand, p. 12–16.

Schmidt, Susanne, Dennison, W.C., Moss, G.J., and Stewart G.R., 2004, Nitrogen ecophysiology of 

Heron Island, a subtropical coral cay of the Great Barrier Reef, Australia: Functional Plant Biology, v. 

31, no. 5, p. 519–528.

Shea, E.L., Dolcemascolo, Glenn, Anderson, C.L., Barnston, Anthony, Guard, C.P., Hamnett, M.P., 

Kubota, S.T., Lewis, Nancy, Loschnigg, Johannes, and Meehl, Gerald, 2001, Preparing for a changing 

climate—the potential consequences of climate variability and change: Honolulu, Hawai`i, East-West 

Center, 100 p.

Society for Ecological Restoration International Science and Policy Working Group, 2004, The SER 

international primer on ecological restoration, Tucson: Society for Ecological Restoration 

International, accessed September1, 2009,

http://www.ser.org/content/ecological_restoration_primer.asp.

Spear, L.B., Ainley, D.G., and Ribic, C.A., 1995, Incidence of plastic in seabirds from the tropical 

Pacific, 1984–91—relation with distribution of species, sex, age, season, year and body-weight:

Marine Environmental Research, v. 40, no. 2, p. 123–146.
52

Spicer, R.A., and Newberry, D.M., 1979, The terrestrial vegetation of an Indian Ocean coral island—

Wilingili, Addu Atoll, Maldive Islands: Atoll Research Bulletin, v. 231, p. 1–14.

Streets, T.H., 1877, Some account of the natural history of the Fanning group of islands: American 

Naturalist, v. 11, no. 2, p. 65–72.

Suchanek, Tom, Hart, Kristen, Kulongoski, Justin, Lafferty, Kevin, and Sandoval, Cristina, 2007, 

Palmyra Atoll, mid Pacific 28 October–6 November 2007: Honolulu, Hawai`i, U.S. Fish and Wildlife 

Service Administrative Report, 10 p.

Towns, D.R., Atkinson, I.A.E., and Daugherty, C.H., 2006, Have the harmful effects of introduced rats 

on islands been exaggerated?: Biological Invasions, v. 8, p. 863–891.

Towns, D.R., Wardle, D.A., Mulder, C.P.H., Yeates, G.W., Fitzgerald, B.M., Parish, G.R., Bellingham, 

P.J., and Bonner, K.I., 2009, Predation of seabirds by invasive rats—multiple indirect consequences 

for invertebrate communities: Oikos, v. 118, no. 3, p. 420–430.

Tribble, Gordon, 2008, Ground water on tropical Pacific Islands-understanding a vital resource: U.S. 

Geological Survey Circular 1312, 35 p.

Underwood, M.R., Peterson, F.L., and Voss, C.I., 1992, Groundwater lens dynamics for atoll islands: 

Water Resources Research, v. 28, no. 11, p. 2889–2902.

U.S. Fish and Wildlife Service, 2001, Biological integrity, diversity, and environmental health: Policy

601 FW 3, accessed September1, 2009, http://www.fws.gov/policy/601fw3.html.

U.S. Fish and Wildlife Service, 2002, Birds of conservation concern 2002: Arlington, Va., Division of 

Migratory Bird Management, 99 p., accessed September1, 2009,

http://www.fws.gov/pacific/migratorybirds/BCC2002.pdf.

U.S. Fish and Wildlife Service, 2004, Palmyra ant control preliminary experiments: Honolulu, Hawai`i,

U.S. Fish and Wildlife Service Administrative Report.

U.S. Fish and Wildlife Service, 2005, Regional seabird conservation plan, Pacific region: Portland, 

Oreg., U.S. Fish and Wildlife Service, Migratory Birds and Habitat Programs, Pacific Region, 262 p.

U.S. Fish and Wildlife Service, 2006, National wildlife refuge system mission and goals and refuge

purposes 601 FW 1, accessed September1, 2009, http://www.fws.gov/policy/601fw1.html.

U.S. Fish and Wildlife Service, 2007, Palmyra Atoll National Wildlife Refuge and Kingman Reef 

National Wildlife Refuge: Federal Register, v. 72, no. 87, p. 25771–25773.

Usinger, R.L., and La Rivers, Ira, 1953, The insect life of Arno: Atoll Research Bulletin, v. 15, p. 1–28.

van Riper III, Charles, van Riper, S.G., and Hansen, W.R., 2002, Epizootiology and effect of avian pox 

on Hawai`ian forest birds: The Auk, v. 119, no. 4, p. 929–942.

Veitch, C.R., and Clout, M.N., 2002, Turning the tide—the eradication of invasive species—

Proceedings of the International Conference on the Eradication of Island Invasives: Gland, 

Switzerland, and Cambridge, U.K., IUCN SSC Invasive Species Specialist Group, 414 p.

Vitousek, P.M., 1990, Biological invasions and ecosystem processes—towards an integration of 

population biology and ecosystem studies: Oikos, v. 57, no. 1, p. 7–13.

Vranjic J.A., 1997, Effects on host plant, in Ben-Dov, Yair, and Hodgson, C.J., eds., Soft scale 

insects—their biology, natural enemies and control, world crop pests, v. 7B: Amsterdam, Elsevier 

Science B.V., 422 p.

Walker, T.A., 1991, Pisonia Islands of the Great Barrier Reef, part 1—the distribution, abundance, and 

dispersal by sea birds of Pisonia grandis: Atoll Research Bulletin, v. 350, part 1, p. 1–23.

Ward, S.H., ed., 1990, Geotechnical and environmental geophysics, v. 2–3: Tulsa, Oklahoma, Society of

Exploration Geophysics.

Way, M.J., 1963, Mutualism between ants and honeydew-producing Homoptera: Annual Review of 

Entomology, v. 8, p. 307–344.
53

Wegmann, Alex, 2005, Palmyra Atoll National Wildlife Refuge forest type map: Honolulu, Hawai`i, 

U.S. Fish and Wildlife Service.

Wells, S.M., Pyle, R.M., and Collins, N.M., 1983, IUCN invertebrate red data book—a contribution to 

the Global Environment Monitoring System: Gland, Switzerland accessed September 1, 2009 at 

http://www.iucnredlist.org/apps/redlist/details/2811/0.

Wetterer, J.K., 2007, Biology and impacts of Pacific island invasive species. 3. The African big-headed 

ant, Pheidole megacephala (Hymenoptera: Formicidae): Pacific Science, v. 61, no. 4, p. 437–456.

White, Ian, Falkland, Tony, Perez, Pascal, Dray, Anne, Metutera, Taboia, Metai, Eita, and Overmars, 

Marc, 2007, Challenges in freshwater management in low coral atolls: Journal of Cleaner Production, 

v. 15, p. 1522–1528.

Wiens, H.J., 1962, Atoll environment and ecology: New Haven-London, Yale University Press, 532 p.

Wil Chee Planning Inc. and SCS Engineers, 1998, Soil boring/monitoring well logs from hospital dump 

site, Palmyra Atoll, Palmyra, U.S.A.: Honolulu, Hawai`i, prepared for Wil Chee - Planning by SCS 

Engineers, 60 p.

Wood, C.M., and Boutilier, R.G., 1985, Osmoregulation, ionic exchange, blood chemistry, and 

nitrogenous waste excretion in the land crab Cardisoma carnifex—a field and laboratory study:

Biological Bulletin, v. 169, no. 1, p. 267–290.

Woodward, L.A., 2000, U.S. Fish and Wildlife Service Pacific Islands Ecoregion Level I PreAcquisition Contaminant Survey for the proposed Palmyra Atoll National Wildlife Refuge: Honolulu, 

Hawai`i, U.S. Fish and Wildlife Service Administrative Report, 28 p.

Woodward, Lee Ann, 2001, U.S. Fish and Wildlife Service Pacific Islands Ecoregion Environmental 

Site Assessment Level III Survey: Honolulu, Hawai`i, U.S. Fish and Wildlife Service Administrative 

Report, 36 p.

Young, H.S., McCauley, D.J., Dunbar, R.B., and Dirzo, Rodolfo, 2010a, Plants cause ecosystem 

nutrient depletion via the interruption of bird-derived spatial subsidies: Proceedings of the National 

Academy of Sciences, v. 107, no. 5, p. 2072–2077.

Young, H.S., Raab, T.K., McCauley, D.J., Briggs, A.A., and Dirzo, Rodolfo, 2010a, The coconut palm, 

Cocos nucifera, impacts forest composition and soil characteristics at Palmyra Atoll, Central Pacific: 

Journal of Vegetation Science, v. 21, no. 6, p. 1058-1068.

Young, H.S., Shaffer, S.A., McCauley, D.J., Foley, D.G., Dirzo, Rodolfo, and Block, B.A., 2010c,

Resource partitioning by species but not sex in sympatric boobies in the Central Pacific Ocean:

Marine Ecology Progress Series, v. 403, p. 291–301.
54

Table 1. Terrestrial plant species that have been identified at Palmyra Atoll. 

[Status listed according to Freeman (2006a) with native species shown in bold, species reported as no longer occurring 

grayed out, and contradictory assignments for distribution (D) and abundance (A) shown in boxes (modified from Herbst, 

1992, and Freeman, 2006a, b). D = Distribution across the whole of Palmyra Atoll: W = Widespread (>12 islets), S = 

Scattered (6-12 islets), L = Limited (1-5 islets), X = Extinct on Palmyra Atoll (0 islets). A = Abundance across whole of 

Palmyra Atoll: A = Abundant, C = Common, U = Uncommon, R = Rare, P = Present (for cultivated species), and X = 

Extinct on Palmyra Atoll]

Species Status D A

Abelmoschus sp. nonnative L P

Acalypha wilkesiana cultivated ornamental plant no longer occurring X X

Allium cepa cultivated food plants no longer occurring X X

Aloe vera nonnative L P

Anacardium occidentale cultivated food plants no longer occurring X X

Ananas comosus cultivated food plants no longer occurring X X

Annona sp. cultivated food plants no longer occurring X X

Araucaria sp. nonnative L P

Artocarpus altilis nonnative L P

Asparagus sp. cultivated food plants no longer occurring X X

Asplenium nidus native W U

Barringtonia asiatica native L R

Bidens alba nonnative L R

Boerhavia tetranda native S U

Bolboshoenus sp. native L U

Caesalpinia major native X X

Calophyllum inophyllum nonnative X1 U

Cannabis indica cultivated ornamental plant no longer occurring X X

Carica papaya nonnative L P

Casuarina equisetifolia nonnative L R

Cenchrus echinatus accidental no longer occurring X X

Chamaesyce hirta nonnative L C

Chamaesyce hypericifolia nonnative L C

Chamaesyce hyssopifolia nonnative 2

Chloris inflata nonnative L U

Citrullus lanatus cultivated ornamental plant no longer occurring X X

Citrus aurantium cultivated food plants no longer occurring L X

Citrus sp. nonnative L P

Coccoloba uvifera nonnative X1 U

Cocos nucifera possibly nonnative W A

Codiaeum variegatum var. pictum cultivated ornamental plant no longer occurring X X

Conyza bonariensis nonnative X C
55

Table 1. Terrestrial plant species that have been identified at Palmyra Atoll.—Continued

Species Status D A

Cordia subcordata native L R

Cordyline fruticosa cultivated ornamental plant no longer occurring X X

Crocus nonnative L P

Crotalaria incana nonnative L U

Cucumus sativus cultivated food plants no longer occurring X X

Cyperrus rotundus nonnative 2

Cyperus alternifolius accidental no longer occurring X X

Cyrtosperma chamissonis cultivated ornamental plant no longer occurring L X

Digitaria pacifica nonnative L U

Digitaria setigera nonnative L U

Eleusine indica nonnative X X

Emilia sonchifolia accidental no longer occurring L X

Entada phaseoloides native X X

Epipremnum pinnatum nonnative X1 C

Eragrostis scabriflora nonnative L R

Eragrostis tenella nonnative L U

Erectites hieracifolia accidental no longer occurring X X

Erythrina variegate var. orientalis nonnative L X

Euphorbia cyanthophora cultivated ornamental plant no longer occurring X X

Euphorbia pulcherrima cultivated ornamental plant no longer occurring X X

Fimbristylis cymosa native L U

Graptophyllum pictum cultivated ornamental plant no longer occurring X X

Guettarda speciosa native L R

Hemigraphis reptans accidental no longer occurring L U

Hernandia sonora native S R

Hibiscus rosa-sinensis nonnative X1 P

Hibiscus tiliaceus possibly nonnative S C

Ipomoea batatas nonnative X X

Ipomoea pes-caprae ssp. brasiliensis nonnative L C

Ipomoea violacea native S C

Kyllinga brevifolia nonnative L C

Laportea ruderalis native W C

Lepidium bidentatum native L X3

Lepturus repens var. palmyrensis native W A

Leucaena leucocephala nonnative L R

Ludwigia octovalvis nonnative L C

Lycopersicon esculentum nonnative L P

Mangifera indica nonnative L P
56

Table 1. Terrestrial plant species that have been identified at Palmyra Atoll.—Continued

Species Status D A

Mariscus javanicus native L U

Mentha sp. nonnative L P

Morus sp. cultivated food plants no longer occurring L X

Musa xparadisiaca nonnative L P

Neisosperma oppositifolia native X1 R

Nephrolepis hirsutula nonnative L U

Nothopanax scutellarum cultivated ornamental plant no longer occurring X X

Ocimum basilicum nonnative L P

Ophioglossum petiolata accidental no longer occurring X X

Orchid nonnative L P

Ornamental Ginger nonnative L P

Oxalis corniculata accidental no longer occurring X X

Pandanus fischerianus native W C

Paspalum fimbriatum accidental no longer occurring X X

Paspalum orbiculare nonnative L C

Passiflora edulis cultivated food plants no longer occurring L X

Persea americana cultivated food plants no longer occurring X X

Phaseolus sp. cultivated food plants no longer occurring X X

Phoenix sp. cultivated food plants no longer occurring X X

Phyllanthus amarus nonnative L C

Phymatosorus scolopendria native W A

Pilea microphylla nonnative L C

Pisonia grandis native W A

Pluchea carolinensis nonnative L A

Pluchea indica nonnative L C

Pluchea x fosbergii nonnative A

Plumeria sp. cultivated ornamental plant no longer occurring X X

Polyscias balfouriana cultivated ornamental plant no longer occurring X X

Portulaca oleracea nonnative S C

Premna serratifolia native L R

Pseuderanthemum carruthersii cultivated ornamental plant no longer occurring X X

Psilotum nudum native S R

Pteris ensiformis nonnative L U

Pycreus polystachyos nonnative L C

Raphanus sativus cultivated food plants no longer occurring X X

Rosa sp. cultivated ornamental plant no longer occurring X X

Sansevieria trifasciata cultivated ornamental plant no longer occurring X X

Scaevola sericea native W A
57

Table 1. Terrestrial plant species that have been identified at Palmyra Atoll.—Continued

Species Status D A

Shefflera actinophylla nonnative L R

Sida rhombifolia accidental no longer occurring X X

Spathoglottis plicata nonnative L X

Spermacoce assurgens nonnative S C

Sporobolus indicus nonnative L U

Stachytarpheta jamaicensis nonnative C

Stachytarpheta urticifolia nonnative L C

Suriana maritima native L X4

Synedrella nodiflora nonnative L U

Syzygium malaccense cultivated ornamental plant no longer occurring X X

Temptations nonnative L P

Terminalia catappa possibly nonnative S A

Thespesia populnea cultivated ornamental plant no longer occurring L X

Tournefortia argentea native W A

Tridax procumbens nonnative L R

Triumfetta procumbens native L A

Vernonia cinerea var. parviflora nonnative L A

Viola sp. cultivated ornamental plant no longer occurring X X

Vitex trifolia nonnative L R

Zea mays cultivated food plants no longer occurring X X

1

Recorded as “extinct” at Palmyra Atoll, but seen at Palmyra Atoll subsequent to these data.

2

New species record collected by Depkin identification from Herbst (2002); no distribution or abundance data available.

3

Recorded in Freeman (2006b) as last seen in 1938.

4

Recorded in Freeman (2006b) as "may be extinct".
58

Table 2. Native terrestrial vascular plant species that have been identified at Palmyra Atoll with qualitative 

descriptions of their distribution and abundance.

[Modified from Herbst (1992) and Freeman (2006a, 2006b). Species reported as no longer occurring grayed

out and contradictory assignments for distribution and abundance shown in boxes.

Distribution across the whole of Palmyra Atoll: Widespread (>12 islets), Scattered (6-12 islets),

Limited (1-5 islets), Extinct on Palmyra Atoll (0 islets)]

Species Distribution Abundance

Asplenium nidus Widespread Uncommon

Barringtonia asiatica Limited Rare

Boerhavia tetranda Scattered Uncommon

Bolboshoenus sp. Limited Uncommon

Caesalpinia major Locally extinct Locally extinct

Cordia subcordata Limited Rare

Entada phaseoloides Locally extinct Locally extinct

Fimbristylis cymosa Limited Uncommon

Guettarda speciosa Limited Rare

Hernandia sonora Scattered Rare

Ipomoea violacea Scattered Common

Laportea ruderalis Widespread Common

Lepidium bidentatum Limited Locally extinct1

Lepturus repens var. palmyrensis Widespread Abundant

Mariscus javanicus Limited Uncommon

Neisosperma oppositifolia Locally extinct2 Rare

Pandanus fischerianus Widespread Common

Phymatosorus scolopendria Widespread Abundant

Pisonia grandis Widespread Abundant

Premna serratifolia Limited Rare

Psilotum nudum Scattered Rare

Scaevola sericea Widespread Abundant

Suriana maritima Limited Locally extinct3

Tournefortia argentea Widespread Abundant

Triumfetta procumbens Limited Abundant

1 Recorded in Freeman (2006b) as last seen in 1938.

2 Recorded as extinct by Freeman (2006b), but seen at Palmyra Atoll subsequent to these data.

3 Recorded elsewhere by Freeman (2006b) as “may be extinct” (Suriana maritima may be locally 

extinct).
59

Table 3. Collectors of vascular plants at Palmyra Atoll in chronological order. 

[From Herbst (1992)]

Name Date of collections

Thomas H. Streets December 12–27, 1873

Joseph F.C. Rock July12–28, 1913

Charles Montague Cooke, Jr. July 12–28, 1913

Henry E. Cooper July 12–28, 1913, March 1914

Edwin H. Bryan, Jr. March 23, 1935, August11–12, 1938

Albert F. Judd June 13, 1935

Donald D. Mitchell June 13, 1935

Ashley Brown October 17, 1939

Margaret Hill October 1949, December 1949

E. Yale Dawson October 15–21, 1958

Henry S. Moeller December 28, 1959–January 3, 1960

Charles Robert Long June 6–7, 1964, November 27–28, 1964

Derral R. Herbst September 18–25, 1987, February 24– March 3, 1992
60

Table 4. Mammal species identified at Palmyra Atoll.

Family/species Status

Family Canidae (dogs)

 Canis familiaris nonnative

Family Felidae (cats)

 Felis catus nonnative

Family Suidae (hogs, pigs)

 Sus domestica nonnative—no longer present

Family Muridae (mice, rats)

 Rattus rattus nonnative
61

Table 5. Avifauna of Palmyra Atoll. 

[Modified from Fefer (1987) and adapted from R.B. Clapp (U.S. Geological Survey, written commun., 1966 in Fefer, 1987). 

Domestic chicken reported in Flint and others (1992); black tern reported by A. Wegmann, oral commun., University of 

Hawai`i, 2008]

Species Status

Sea birds

Audubon’s shearwater (Puffinus lherminieri) Rare visitant

Black noddy (Anous minutus) Abundant resident

Black tern (Chlidonias niger) Rare visitant

Brown booby (Sula leucogaster) Common resident

Brown noddy (Anous stolidus) Common resident

Great crested tern (Sterna bergii) Rare visitant

Great frigatebird (Fregata minor) Common resident

Lesser frigatebird (Fregata ariel) Rare visitant

Masked booby (Sula dactylatra) Uncommon resident

Red-footed booby (Sula sula) Abundant resident

Red-tailed tropicbird (Phaethon rubricauda) Uncommon resident

Sooty tern (Sterna fuscata) Abundant resident

White tern (Gygis alba) Common resident

White-tailed tropicbird (Phaethon lepturus) Uncommon resident

Shore birds

Bristle-thighed curlew (Numenius tahitiensis) Abundant migrant

Lesser golden plover (Pluvialis dominica) Abundant migrant

Ruddy turnstone (Arenaria interpres) Abundant migrant

Sanderling (Calidris alba) Uncommon migrant

Sharp-tailed sandpiper (Calidris acuminata) Uncommon migrant

Wandering tattler (Heteroscelus incanus) Abundant migrant

Accidentals and introductions

American wigeon (Anas americana) Accidental

Cattle egret (Bubulcus ibis) Accidental

Crested mynah (Acridotheres cristatellus) Introduction (extirpated)

Domestic chicken (Gallus gallus) Introduction (extirpated)

Eurasian wigeon (Anas penelope) Accidental

Franklin’s gull (Larus pipixcan) Accidental

Green-winged teal (Anas crecca) Accidental

Laughing gull (Larus atricilla) Accidental

Mallard (Anas platyrhynchos) Accidental

Pintail (Anas acuta) Accidental

Shoveler (Anas clypeata) Accidental
62

Table 6. Herpetofauna using the terrestrial habitat at Palmyra Atoll.

Family/species Status

Amphibians

Family Bufonidae (toads)

 Bufo marinus nonnative last seen in 2002

Reptiles

Family Gekkonidae (geckos)

 Lepidodactylus n. sp. native

 Lepidodactylus lugubris possibly nonnative

 Hemidactylus frenatus nonnative

Turtles

Family Cheloniidae (sea turtles)

 Chelonia mydas native

 Eretmochelys imbricata native
63

Table 7. Terrestrial native and nonnative arthropod species identified at Palmyra Atoll.

[Names of native species are in bold. Taxa: G. sp. indicates undetermined genus and species. The origin listed for each 

species was modified from Handler and others (2007)]

Order/family Taxa Origin

Order Araneae (spiders)

 Agelenidae Agelenidae G. sp. Cryptogenic

 Araneidae Neoscona theisi (Walckenaer, 1841) Introduced

 Heteropodidae Heteropoda venatoria (Linnaeus, 1767) Introduced

 Pholcidae Smeringopus pallidus (Blackwall, 1856) Introduced

 Salticidae Hasarius adansoni (Audouin, 1826) Introduced

Menemerus bivittatus (Dufour, 1831) Introduced

Messua cf. felix (Peckham & Peckham, 1901) Introduced

Phintella versicolor (C. L. Koch, 1846) Cryptogenic

Plexippus paykulli (Audouin, 1826) Introduced

Salticidae G. sp. 1 Cryptogenic

Salticidae G. sp. 2 Cryptogenic

Sandalodes sp. Cryptogenic

 Scytodidae Scytodes longipes (Lucas, 1845) Introduced

Scytodes striatipes (L. Koch, 1872) Introduced

 Tetragnathidae Tetragnatha keyserlingi (Simon, 1890) Native?

 Theridiidae Coleosoma floridanum (Banks, 1900) Introduced

Latrodectus geometricus (C. L. Koch, 1841) Introduced

Nesticodes rufipes (Lucas, 1846) Introduced

Order Blattodea (cockroaches)

 Blaberidae Pycnoscelus indicus (Fabricius, 1775) Introduced

 Blatellidae Supella longipalpa (Fabricius, 1798) Introduced

 Blattidae Periplaneta americana (Linnaeus, 1758) Introduced

Periplaneta australasiae (Fabricius, 1775) Introduced

Platyzosteria soror (Brunner, 1865) Introduced

Order Coleoptera (beetles)

 Anthribidae Araecerus vieillardi (Montrouzier, 1860) Introduced

Mauia subnotatus (Boheman, 1859) Introduced

 Carabidae Carabidae G. sp Cryptogenic

 Cerambycidae Cerambycidae G. sp. 1 Cryptogenic

Cerambycidae G. sp. 2 Cryptogenic

 Coccinellidae Coccinellidae G. sp. Cryptogenic

Coelophora inaequalis (Fabricius, 1775) Introduced
64

Table 7. Terrestrial native and nonnative arthropod species identified at Palmyra Atoll.—Continued

Order/family Taxa Origin

Coccinellidae (continued) Diomus notescens (Blackburn, 1889) Introduced

Rhyzobius lophanthae (Blaisdell, 1892) Introduced

Cryptophagidae Toramus(?) sp. Cryptogenic

Cucujidae Psammoecus insularis (Sharp, 1885) Introduced

Elateridae Conoderus pallipes (Eschscholtz, 1829) Introduced

Melanoxanthus melanocephalus (Fabricius, 1781) Introduced

Hydrophilidae Dactylosternum abdominale (Fabricius, 1792) Introduced

Nitidulidae Carpophilus humeralis (Fabricius, 1798) Introduced

Oedemeridae Eobia bicolor (Fairmaine, 1849) Introduced

Eobia decolor (Fairmaine, 1849) Introduced

Eobia kanack (Fairmaine, 1849) Introduced

Eobia sinensis (Gemminger, 1870) Introduced

Sessinia livida (Fabricius, 1775) Introduced

Pselaphidae Pselaphidae G. sp. Cryptogenic

Ptilidae Ptilidae G. sp. Cryptogenic

Scarabaeidae Saprosites pygmaeus (Harold, 1877) Introduced

Scolytidae Xyleborus perforans (Wollaston, 1857) Introduced

Staphylinidae Philonthus discoideus (Gravenhorst, 1802) Introduced

Order Dermaptera (earwigs)

Carcinophoridae Euborellia annulipes (Lucas, 1847) Introduced

Order Diptera (true flies)

Agromyzidae Liriomyza sativae (Blanchard, 1938) Introduced

Liriomyza sp. Cryptogenic

Calliphoridae Chrysomya megacephala (Fabricius, 1794) Introduced

Lucilia sericata (Meigen, 1826) Introduced

Canaceidae Canaceoides sp. Cryptogenic

 Nocticanace marshallensis (Wirth) Native?

Ceratopogonidae Ceratopogonidae G. sp. Cryptogenic

Dasyhelea sp. Cryptogenic

Chironomidae Chironomidae G. sp. Cryptogenic

Clunio sp. Cryptogenic

Chloropidae Cadrema pallida (Loew, 1865) Introduced

Gaurax bicoloripes (Malloch, 1933) Introduced

Hippelates sp. Cryptogenic

Culicidae Aedes albopictus (Skuse, 1894) Introduced

Culex quinquefasciatus (Say, 1823) Introduced
65

Table 7. Terrestrial native and nonnative arthropod species identified at Palmyra Atoll.—Continued

Order/family Taxa Origin

Dolichopodidae Chrysosoma complicatum (Becker, 1922) Introduced

Chrysosoma globiferum (Wiedemann, 1830) Introduced

Chrysosoma sp. Cryptogenic

Chrysosoma sp. nr. molestum (Parent) Cryptogenic

 Chrysotus javanensis (de Meijere, 1916) Native?

Dolichopodidae G. sp. Cryptogenic

Drosophilidae Cacoxenus perspicax (Knab, 1914) Introduced

Drosophilidae Drosophila ananassae (Doleschall, 1858) Introduced

Ephydridae Discocerina mera (Cresson, 1939) Introduced

Hecamede granifera (Thomson, 1869) Introduced

Hostis guamensis (Cresson, 1945) Introduced

Placopsidella marquesana (Malloch, 1933) Introduced

Placopsidella sp. Cryptogenic

Scatella stagnalis (Fallen, 1813) Introduced

Hippoboscidae Olfersia aenescens (Thomson, 1869) Native?

Limoniidae Limonia sp. nr. perkinsi (Grimshaw) Introduced

 Styringomyia didyma (Grimshaw, 1901) Native

Lonchaeidae Lamprolonchaea metatarsata (Kertesz, 1901) Introduced

Milichilidae Milichiella lacteipennis (Loew, 1865) Introduced

Muscidae Atherigona orientalis (Schiner, 1868) Introduced

Atherigona sp. Cryptogenic

Musca domestica (Linnaeus, 1758) Introduced

Muscidae G. sp. Cryptogenic

Phoridae Chonocephalus sp. Cryptogenic

Platystomatidae Scholastes lonchifera (Hendel, 1914) Introduced

Sarcophagidae Parasarcophaga misera (Walker) Introduced

Parasarcophaga sp. Cryptogenic

Sarcophaga peregrina (Robineau-Desvoidy, 1830) Introduced

Sarcophagidae G. sp. Cryptogenic

Sciaridae Sciaridae G. sp. Cryptogenic

Stratiomyidae Cephalochrysa maxima (Bezzi, 1928) Introduced

Syrphidae Eristalinus arvorum (Fabricius, 1787) Introduced

Simosyrphus grandicornis (Macquart, 1842) Introduced

Syritta sp. Cryptogenic

Tethinidae Dasyrhicnoessa insularis (Aldrich, 1931) Native?

Tethina sp. Cryptogenic

Ulididae Ulididae G. sp. Cryptogenic
66

Table 7. Terrestrial native and nonnative arthropod species identified at Palmyra Atoll.—Continued

Order/family Taxa Origin

Order Hemiptera (Heteroptera) (true bugs)

Cynidae Geotomus pygmaeus (Dallas, 1851) Introduced

Gerridae Halobates micans (Eschscholz, 1822) Native

Miridae Miridae G. sp. Cryptogenic

 Trigonotylus brevipes (Jakovlev, 1880) Native?

Reduviidae Reduviidae G. sp. Cryptogenic

Order Hemiptera (Sternorrhyncha) (aphids, whiteflies, scale insects)

Aleyrodidae Aleyrodidae G. sp. Introduced

Aphididae Aphididae G. sp. Cryptogenic

Coccidae Pulvinaria urbicola (Cockerell & Parrott, 1899) Introduced

Margarodidae Icerya purchasi (Maskell, 1879) Introduced

Pseudococcidae Dysmicoccus brevipes (Cockerell, 1893) Introduced

Dysmicoccus neobrevipes (Beardsley, 1959) Introduced

Ferrisia virgata (Cockerell, 1893) Introduced

Planococcus citri (Risso, 1813) Introduced

Order Hymenoptera (ants, bees, wasps)

Aphelinidae Coccophagus ceroplastae (Howard, 1895) Introduced

Euryischomyia flavithorax (Girault & Dodd, 1915) Introduced

Cynipidae Kleidotoma sp. Cryptogenic

Diapriidae Trichopria sp. Cryptogenic

Encyrtidae Metaphycus flavus (Howard, 1881) Introduced

Eulophidae Aprostocetus hagenowii (Ratzeburg, 1852) Introduced

Hemiptarsenus semialbiclavus (Girault, 1916) Introduced

Evaniidae Evania appendigaster (Linnaeus, 1758) Introduced

Formicidae Cardiocondyla emeryi (Forel, 1881) Introduced

 Cardiocondyla minutior (Forel) Introduced

Hypoponera punctatissima (Roger, 1859) Introduced

Monomorium floricola ( Jerdon, 1851) Introduced

Paratrechina bourbonica (Forel, 1886) Introduced

Paratrechina longicornis (Latreille, 1802) Introduced

Paratrechina vaga (Forel, 1901) Introduced

Pheidole megacephala (Fabricius, 1793) Introduced

Tapinoma melanocephalum (Fabricius, 1793) Introduced

Tetramorium bicarinatum (Nylander, 1847) Introduced

Megachilidae Megachile fullawayi (Cockerell, 1914) Introduced

Megachile sp. Cryptogenic
67

Table 7. Terrestrial native and nonnative arthropod species identified at Palmyra Atoll.—Continued

Order/family Taxa Origin

Scelionidae Scelionidae G. sp. Cryptogenic

Sphecidae Sceliphron caementarium (Drury, 1770) Introduced

Sphecidae G. sp. Cryptogenic

Vespidae Pachodynerus nasidens (Latreille, 1802) Introduced

Polistes aurifer (Saussure, 1853) Introduced

Order Isopoda (pillbugs)

Philosciidae Australophiloscia societatis (Maccagno, 1932) Native

Order Lepidoptera (moths, 

butterflies)

Agonoxenidae Agonoxena argaula (Meyrick, 1921) Introduced

Cosmopterigidae Anatrachyntis incertulella (Walker, 1864) Introduced

Crambidae Piletocera signiferalis (Wallengren) Cryptogenic

Gelechiidae Stoeberhinus testaceus (Butler, 1881) Introduced

Gracillariidae Gracillariidae G. sp. Cryptogenic

Noctuidae Chrysodeixis eriosoma (Doubleday, 1843) Introduced

Spodoptera litura (Fabricius, 1775) Introduced

Nymphalidae Hypolimnas bolina (Linnaeus, 1758) Native?

Sphingidae Agrius cingulata (Fabricius, 1775) Introduced

Tineidae Erechthias simulans (Butler, 1882) Introduced

Opogona sp. Cryptogenic

Order Odonata (dragonflies, damselflies)

Aeshnidae Anax junius (Drury, 1770) Native

Coenagrionidae Ischnura aurora (Brauer, 1865) Native

Libellulidae Crocothemis servilea (Drury, 1770) Introduced

 Pantala flavescens (Fabricius, 1770) Native

Order Orthoptera (grasshoppers, crickets, katydids)

Acrididae Oxya japonica (Thunberg, 1824) Introduced

Gryllidae Cycloptilum sp. Cryptogenic

Ornebius sp. Cryptogenic

 Speonemobius tigrinus (Saussure) Native?

Teleogryllus oceanicus (Le Guillou, 1841) Introduced

Pyrgomorphidae Atractomorpha sinensis (Bolivar, 1905) Introduced

Tettigoniidae Conocephalus saltator (Saussure, 1859) Introduced

 Phisis holdhausi (Karny, 1926) Native
68

Table 8. Terrestrial crabs of Palmyra Atoll.

Family/species Status

Family Coenobitidae (land hermit crabs)

 Birgus latro native

 Coenobita perlatus native

 Coenobita brevimanus native

Family Gecarcinidae (land crabs)

 Cardisoma carnifex native

 Cardisoma rotundum native

Family Grapsidae (marsh, shore, and talon crabs)

 Geograpsus crinipes native
69

Table 9. Palmyra Atoll resources of concern. 

[Question mark (?) indicates key uncertainty regarding the impact of the limiting factor and requires further investigation. 

“State” is an approximation of the deviation from recent or historical surveys, trips, and studies of Palmyra Atoll on a scale 

of Low - Moderate - High. “Target” descriptions often imply that we know current age structure and population status. Beach 

nesters are included in this plan because of proximity to terrestrial forest and thus possible direct impact from forest 

management.]

Resource Species Current “State” Limiting Factors Target 

Plants

Pisonia grandis

forest

Pisonia grandis forest 

native species 

constituents

Moderate - High • Coconut palm 

competition

• Retain to the extent 

possible existing large 

and mid-sized trees

• Phymatosorus 

scolopendria

competition?

• Increase proportion 

of small trees

• Altered substrates? • Ensure that Pisonia 

grandis recolonizes 

canopy gaps

• Contaminants? • Increase Pisonia 

grandis in 50-m buffer 

around existing stands

• Altered 

groundwater levels?

• Storm events by 

direct damage to trees

• Storm events 

increasing 

groundwater salinity?

• Low abundance of 

ectomycorrhizae?

• Altered nutrient 

cycling/availability

Coastal strand 

forest

Coastal strand native 

species constituents

Low • Coconut palm

competition

• Continuous canopy

• Erosion

• Contaminants?

• Storm events by 

direct damage to trees

Grassland Grassland native 

species constituents in 

particular Lepturus 

repens var. 

palmyrensis

Moderate - High • Forest succession? • Maintain at levels 

documented by 

Freeman (2006a)

• Coconut palm 

competition?

• Altered substrates
70

Table 9. Palmyra Atoll resources of concern. —Continued 

Resource Species Current “State” Limiting Factors Target 

Animals

Ground nesters Brown booby Low • Rat predation • Increase production

Masked bobby • Lowered pelagic 

forage

• Increase population 

size

Red-tailed tropicbird

• Reduced nesting 

substrate

Sooty tern

Burrowing 

nesters

Shearwaters Extirpated? • Rat predation • Natural selfsustaining population

Petrels • Pelagic forage

• Nesting substrate

Tree nesters Red-footed booby Low • Lowered pelagic 

forage

• Increase population 

size

Noddies • Reduced Pisonia 

grandis and tree 

heliotrope availability

Shore and 

intertidal flats 

and forest 

interior

Bristle-thighed 

curlew

Present but no 

best judgment of 

state at this time

• Contaminants? • Decrease fall 

mortality

• Rat predation • Increase Alaska 

breeding density and 

(or) fecundity

Forest floor Coconut crab Moderate • Dense understory • Increase production

(A. Wegmann, 

University of Hawai`i, 

oral commun., 2008)

• Increase distribution 

within Palmyra Atoll

• Rat predation • Increase population 

size

• Habitat alteration by 

coconut palm?

Forest Lizards Low • Rat predation • Increase population 

size

• Nonnative geckos 

(competition, parasites)

• Increase distribution

Forest Insects Present but no 

best judgment of 

state at this time

• Lack of inventory 

information

• Self-sustaining 

populations of native 

insects

Beach nesters Sea turtles Present at 

Palmyra Atoll 

National 

Wildlife Refuge 

no current 

evidence of 

nesting

• Rat predation (eggs 

and hatchlings)

• Natural selfsustaining population?

• Islet configuration

• Lagoon hydrology
71

Table 10. Experts consulted regarding Palmyra Atoll management planning.

Name Affiliation

Lisa Balance National Oceanic and Atmospheric Administration

Southwest Fisheries, La Jolla, California

Steve Barclay U.S. Fish and Wildlife Service

Pacific/Remote Islands National Wildlife Refuge Complex, Honolulu, Hawai`i

Pat Biley The Nature Conservancy, Maui Program, Honolulu, Hawai`i

John Collen Centre for Marine Environmental and Economic Research, Victoria University of 

Wellington

Chris Depkin U.S. Fish and Wildlife Service

Pacific/Remote Islands National Wildlife Refuge Complex, Honolulu, Hawai`i

Donald Drake University of Hawai`i, Honolulu, Hawai`i

Elizabeth Flint U.S. Fish and Wildlife Service

Pacific/Remote Islands National Wildlife Refuge Complex, Honolulu, Hawai`i

Kristen Hart U.S. Geological Survey

Florida Integrated Science Center, Fort Lauderdale, Florida

Justin Kulongoski U.S. Geological Survey

California Water Science Center, San Diego, California

Matthew McKown University of North Carolina, Chapel Hill, North Carolina

Barrie Morgan The Nature Conservancy, Palmyra Program, Honolulu, Hawai`i

Diana Papoulias U.S. Geological Survey

Columbia Environmental Research Center, Columbia, Missouri 

Robert Pitman National Oceanic and Atmospheric Administration

Southwest Fisheries, La Jolla, California

Joanna Smith University of Washington, Seattle, Washington

William Smith U.S. Fish and Wildlife Service

Pacific/Remote Islands National Wildlife Refuge Complex, Honolulu, Hawai`i

Eleanor Sterling American Museum of Natural History

New York, New York

Alex Wegmann University of Hawai`i, Honolulu, Hawai`i, and Island Conservation

Lee Ann Woodward U.S. Fish and Wildlife Service

Pacific/Remote Islands National Wildlife Refuge Complex, Honolulu, Hawai`i

Hillary Young Stanford University, Stanford, California
72

Figure 1. Map of Palmyra Atoll. 
73

Figure 2. State-transition model for restoration of Pisonia grandis forest within Palmyra Atoll. Lines and arrows 

indicate transitions between states (dotted lines indicate obstacles to restoration, and solid lines indicate 

opportunities for restoration).
74

Appendix: Phase 1 Workplan

Applies to “Terrestrial Forest Management Plan for Palmyra Atoll”:

Coconut Palm Control Plan

Habitat Goal (HG1): Protect, maintain, and where possible restore terrestrial ecosystem integrity—the 

natural biological communities and their associated biodiversity, habitats, populations, ecological 

processes, and environmental health of Palmyra Atoll.

Applies to multiple Objectives in “Terrestrial Forest Management Plan for Palmyra Atoll”:

• (HG1-O6) Maintain existing Pisonia grandis stands and promote new growth and expansion.

• (HG1-O6a) Maintain large trees in Pisonia grandis stands that incurred extensive large-tree 

mortality during the scale infestation.

• (HG1-O6b) Maintain regeneration of small trees in Pisonia grandis stands that incurred 

moderate mortality during the scale infestation. 

• (HG1-O6c) Implement a “no net loss” Pisonia grandis strategy. 

• (HG1-O7) Control coconut palm (Cocos nucifera) succession and incursion into Pisonia grandis 

stands that have suffered moderate to extensive mortality during the scale infestation.

• (HG1- O8) Create openings for native coastal shrubs to colonize monotypic coconut palm stands.

• (HG1-O13) Accelerate native forest restoration. 

Background

The U.S. Fish and Wildlife Service (FWS) has a proposed invasive plant species removal plan 

intended to be implemented in 2010. While the plan is being evaluated and prioritized, it has been 

suggested that the invasive removal team dedicate some effort toward work on various parts of Palmyra 

Atoll. Suggested activities include the removal of Casuarina, Araucaria, and other similar nonnative or 

invasive species from Cooper Islet. There may also be some effort directed toward the removal of new 

invasive plants appearing on various islets, such as Pluchea on Cooper Islet. As yet, the FWS priorities 

are unclear regarding implementation of the invasive species removal plan. The discussion below is 

based on the assumption that the plan will move forward and address the invasive plant issues identified 

by the FWS.

Coconut palm has been shown to deplete nutrients from the terrestrial ecosystem by reducing 

habitat for sea bird roosting and nesting, which in turn reduces nutrient input that sea birds bring in from 

the marine environment (Young and others, 2010). Recent studies also suggest that the eradication of 

rats at Palmyra Atoll will significantly reduce seed and seedling predation pressure on coconut palms

(A. Wegmann, University of Hawai`i, written commun., 2008). Therefore, the U.S. Geological Survey

(USGS) discussed with the FWS and others the possibility of incorporating coconut palm management 

and experimental cuts into the initial invasive plant management effort. While this would clearly be 

time and resource dependent, we include here several prioritized suggestions for coconut palm

management actions consistent with current research and management objectives. This coconut palm 

control plan also assumes the development of a monitoring plan relevant to these actions prior to 

implementation. While adequate resources may not be available through current funding, the priorities 

below are important for the overall conservation and restoration of terrestrial forest ecosystem integrity 

and should be considered for future action.
75

Proposed Actions and Methods

 

We suggest direct management action to remove coconut palms completely from Leslie, Dudley, 

Priority 1

 and (or) Sand Islets. Coconut palm removal from Sand Islet, while perhaps the most desirable, 

 would also be the most time intensive. We suggest Leslie Islet as a first option (as there are lower 

 densities of nesting birds at this site) and Dudley Islet as an alternative option (fig. 1–1). Ainsley Islet 

 could also be added on if time permits.

Methods

• Potential impacts of concern include damaging neighboring native plant species and nearby 

animals (for example, bird nesting, crabs directly and by burrow collapse). To minimize 

these problems, we suggest using a chemical method to kill the mature coconut palms 

(Sandoval and others, 2008) after evaluation that potential release of phytotoxins will not 

harm nontarget species.

• To prevent immediate regeneration by coconut palms it would be necessary to remove all 

nuts on the ground. Ideally, there would also be periodic work to destroy or remove nuts 

falling because of treatment, as well as new nuts washing up on the beaches. Any coconut 

palms found alive 1 year after treatment should be re-treated or mechanically destroyed.

• We suggest leaving all non-nut plant matter to decay on the ground naturally after the 

treatment activities. 

Monitoring Suggestions

We suggest monitoring treated sites immediately before (if mechanical methods are 

used) and after the treatment by using long-term monitoring protocols. Such monitoring should 

be repeated at 1-, 2-, and 5-year intervals and at 5-year intervals thereafter.

 

We recommend removing coconut palms from areas where this action has the potential to

facilitate erosion of dredge fill creating gaps between original islets. This activity could be 

accomplished through poisoning (or mechanical removal if not in proximity to native forests). Three 

target areas include the narrow connecting bridges between Pelican and Holei Islets, between Holei and 

Engineer Islets, and between Kaula and Paradise Islets (fig.1-1). This adaptive management action 

should be done in coordination with geomorphology scientists and be consistent with reef flat and 

lagoon monitoring plan objectives, as well as related siting of focal stations (see “Draft Initial 

Monitoring Plan” [Lafferty and Kushner 2008]) and considered with any lagoon restoration planning 

respectively.

Priority 2

 

Given the long-term interest in large-scale coconut palm removal at Palmyra Atoll and concerns 

about what type of regeneration will result from such a removal, we suggest at least two large 

experimental cuts (at least 20 by 50 m in size). We suggest that one of these cuts be made on the edge 

of coconut palm/native forest and one be made in full coconut palm forest. Since research suggests that 

there is limited or no native propagule bank or native seed rain into coconut palm forest, we believe that 

underplanting would be necessary to facilitate native species succession at these sites. Without any 

underplanting, the cut sites will likely succeed quickly to more coconut palms or Phymatosorus 

scolopendria. The simplest species to use for underplantings would be tree heliotrope (Tournefortia 

argentea), as seedlings are readily available (North Beach and Whippoorwill Islet lagoon sides), can 

succeed both inland and on the coast in high light situations, and are not susceptible to herbivory. 

Priority 3
76

Pisonia grandis cuttings are also good candidates for underplanting. While seedlings of some species 

(for example, Pisonia grandis, Neisosperma oppositifolia) are desirable, they require advance 

germination and caging once transplanted. When conducting these experiments and applications after 

rat eradication, advance germination is not necessary; however, caging is still suggested because of the 

likelihood that crabs may move propagules, making them difficult to monitor, and they may kill 

seedlings.

Methods

We suggest chemical methods for the removal of coconut palms very proximal to Pisonia 

grandis or other uncommon native species and mechanical methods for areas of coconut 

palm only. In areas where chemical methods are possible, planting native species could 

begin before the trees have died. The slow dying process will result in gradually increasing 

light availability for seedlings that will “harden” them in the process, and they will thrive in 

direct sunlight (A. Wegmann, University of Hawai`i, written commun., 2010); however, this 

may result in some mortality if not protected because of damage from falling nuts and fronds 

as coconut palms die.

• Site suggestions: 

• Coconut palm only sites—A top priority would be to target Fern Islet (fig. 1–1) entirely 

and include native plantings with fencing or caging. If this is deemed undesirable for 

esthetic or other reasons, either Strawn or Kaula Islets would be possible alternative sites.

• Native only sites—Papala and Pelican Islets (fig. 1–1) have good boundary sites between 

coconut palms and native forests and would be top priority. Strawn Islet is also an option. It 

has a coconut palm stand near the Pisonia grandis grove, but removal here might be more 

visible to the public. A last option is Holei Islet. The major drawback to this site is the 

ongoing research in multiple locations on the islet and the difficulty in avoiding research 

sites, which could be seriously compromised.

Monitoring Suggestions

We suggest monitoring all sites immediately after the cutting activities and underplanting 

as a restoration research project by using detailed permanent marking and measuring protocols. 

Such monitoring should be repeated at 1-, 2-, and 5-year intervals and at 5-year intervals 

thereafter.

Removing coconut palms from Pisonia grandis gap areas is another target activity. We 

recommend that this removal be done chemically.

Priority 4

Staff

Using the chemical methods described (see Sandoval and others, 2008) on Leslie Island 

extrapolated on the basis of area, initial nut removal will likely take at least as much time as chemical 

treatment, then it can be decreased to periodic 1 time per month checks or 1 time per quarter checks. It 

is unknown whether mechanical methods are comparable in labor requirements. Monitoring should take 

about one-half day per site, depending on site location, complexity, and number of plots.
77

Priority 3 could include various options, but as an assumption of transplanting tree heliotrope

seedlings, a site would probably take 1 day to harvest and plant depending on plant availability and site 

location.

Some uncertainties include determining optimal planting density, site preparation, moving debris 

from coconut palm falls, returning to water seedlings, and so on.

Timing

Initiate coconut palm removal as soon as possible. Avoid activities, particularly mechanical 

treatment of coconut palms, near nesting bird locations between 10 a.m. and 2 p.m. (during the heat of 

the day).

Equipment

Equipment is variable depending on treatment method (chemical: drill, herbicide; mechanical:

machete and (or) chainsaw) and restoration strategy (for example, if fencing or caging).

Support

Travel, supplies, accommodations (room and board), and so on

Cost

To be determined on the basis of whether the work would be done by staff, contractors, or 

volunteers.

Logistical Questions

Will flights to and from Palmyra Atoll and Honolulu, Hawai`i be available as necessary to 

complete proposed actions?

References Cited

Lafferty, K.D., and Kushner, David, 2008, Draft initial monitoring plan for Palmyra Atoll: Sacramento, 

Calif., U.S. Geological Survey, Western Ecological Research Center, 74 p.

Sandoval, Cristina, Biley, Pat, Lafferty, Kevin, Hathaway, Stacie, and Smith, William, 2008,

Evaluation of herbicide application to coconut trees on Palmyra Atoll (Oct 2007 to July 2008). Draft 

Trip Report: Honolulu, Hawai`i, U.S. Fish and Wildlife Service, 3 p.

Young, H.S., McCauley, D.J., Dunbar, R.B., and Dirzo, Rodolfo, 2010, Plants cause ecosystem nutrient 

depletion via the interruption of bird-derived spatial subsidies: Proceedings of the National Academy 

of Sciences, v. 107, no. 5, p. 2072–2077.
78

Figure 1–1. Priority areas for coconut palm removal at Palmyra Atoll.
Publishing support provided by the U.S. Geological Survey

Publishing Network, Sacramento and Tacoma Publishing Service Centers

For more information concerning the research in this report, contact the

 Director, Western Ecological Research Center

3020 State University Drive East

Modoc Hall, Room 3006

Sacramento, CA 95819

http://www.werc.usgs.gov/
Hathaway and others—Terrestrial Forest Management Plan for Palmyra Atoll—Open-File Report 2011–1007