Chapter A. 2019 Wake Atoll Biodiversity Surveys Overview

By Stacie A. Hathaway and Robert N. Fisher

A. Introduction

Wake Atoll (generally referred to hereafter as “Wake”) is part of the Gilbert-Marshall Island chain in the Pacific Ocean, about 3,500 kilometers (km) west of the Hawaiian Islands, 2,600 km east of Guam, 3,200 km southeast of Japan, and 570 km north of Bokak Atoll in the Republic of the Marshall Islands (Bryan, 1959; U.S. Air Force, unpub. data, 2017). Wake is one of the most isolated terrestrial islands in the Pacific (fig. A1; U.S. Air Force, unpub. data, 2017). Wake consists of three islets: (1) Peale, (2) Wake, and (3) Wilkes, arranged in a V-shaped pattern around a central lagoon (fig. A2; Bryan, 1959). Wake is a low atoll with an average elevation of about 4 meters (m), maximum elevation of about 6.4 m above sea level, and a total land area of about 7 square kilometers (km²; U.S. Air Force, unpub. data, 2008). The climate is tropical maritime with little annual temperature variation (U.S. Air Force, unpub. data, 2008). Mean annual temperatures range from 24.4 to 28.3 degrees Celsius (°C), with an annual maximum of 35 °C and a minimum of 20 °C. Rainfall averages about 890 millimeters (mm) per year (Weatherbase, 2020). Together, high temperatures and low rainfall generally keep Wake in a state of drought (U.S. Air Force, unpub. data, 2008). Frequent tropical storms and typhoons generating high winds and waves can cause considerable damage to vegetation and infrastructure (U.S. Air Force, unpub. data, 2008). Wake consists of porous coral rubble and limestone with organic matter in vegetated areas (U.S. Air Force, unpub. data, 2008). Despite low endemism and biodiversity in general, Wake and other atolls protect various natural resources, including several terrestrial and marine natural resources, such as plants, seabirds, shorebirds, lizards, and sea turtles (Engilis and Naughton, 2004; U.S. Fish and Wildlife Service, 2005; Thaman, 2016).

There is no prehistoric evidence that Wake was populated by pre-European Pacific peoples. Heinl (1947) provides an account of the pre-war history of Wake from 1568 to 1941, and additional historical context is contained in the Wake Integrated Cultural Resources Management Plan (Verhaaren and Kullen, unpub. data, 2014) and the Wake Integrated Natural Resources Management Plan (INRMP; U.S. Air Force, unpub. data, 2017). The brief history that follows is summarized from these documents. Wake was discovered in 1568 by Spanish explorers, although credit is given to British Captain William Wake, who rediscovered the island more than 200 years later in 1796. Wake was explored by U.S. Navy Commander Charles Wilkes and naturalist Titian Peale in 1841. The United States formally took possession in 1899. There are reports of several shipwrecks and otherwise limited visitations until the Japanese began landing to harvest bird feathers and fish for shark fins. A group of Japanese castaways were marooned on the atoll at one point. Remaining Japanese camps were abandoned by 1922. Most early zoological and botanical observations are from the Smithsonian’s Tanager Expedition, which carried out a biological reconnaissance at Wake in 1923. The U.S. Navy was given jurisdiction over Wake in 1934 and gave permission for Pan American Airlines (Pan Am) to begin constructing facilities to support weekly trans-Pacific flights. In 1938, the Navy began plans for an outlying military base; however, construction did not begin until January 1941. Construction was not yet completed when the Japanese invaded and overran the island in December 1941 and occupied Wake for the rest of World War II. During the war, the Japanese continued to build many structures underground and behind embankments for protection against repeated bombing. After Japanese surrender in 1945, the atoll returned to U.S. possession and was placed under the jurisdiction of the U.S. Navy. Later, the civil administration was given to what is now known as the Federal Aviation Administration (FAA). Military Air Transport Services and, later, Military Airlift Command provided service to transient U.S. Air Force (USAF) aircraft while at Wake, and Pan Am and other airlines reestablished commercial airline services. During that period, population rose to roughly 2,000 people at the atoll, and an elementary school was constructed. Additional botanical and bird surveys were carried out during this period. In 1972, when long-range jet aircraft reduced the need for Wake as a refueling stop, the FAA transferred jurisdiction to the USAF until 1994. After this time, Wake was administered by the U.S. Army for missile defense and then transferred back to the USAF in 2002. On January 6, 2009, by Presidential Proclamation 8336, Wake Atoll was included in the establishment of the Pacific Remote Islands Marine National Monument. The Secretary of the Interior, in consultation with the Secretary of Commerce, is responsible for the management of the monument. On January 16, 2009, through Secretary Order 3284, the Secretary of the Interior delegated management of the monument to the U.S. Fish and Wildlife Service (USFWS). In accordance with Proclamation 8336, this order (3284) states that Wake is under management by the USAF under the 1972 agreement with the Secretary of the Interior (Code of Federal Regulations 32 Part 935) until the agreement is terminated. The USFWS manages the areas surrounding Wake Atoll from the mean low water line out to 50 nautical miles as part of the National Wildlife Refuge System. Emergent lands are managed by the USAF and used for contingency deployments, an emergency landing facility, and fuel storage. With these activities, construction and maintenance at Wake have continued. In addition, there are currently (2019) regular flights to and from the atoll that carry passengers and supplies. Oceangoing barges bring the bulk of materials and supplies to the atoll and transport used equipment and materials off island.

This history is important for understanding how Wake and its natural resources have been affected over time and illustrates an array of past and current (2019) pathways for invasive species. Non-native species have the potential to be invasive, defined by Executive Order numbers 13112 and 13751, as “species whose presence has caused harm or may cause harm to environmental or human, animal, or plant 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 (Vitousek, 1990; numerous papers in Veitch and Clout, 2002; Engilis and Naughton, 2004). Per the Sikes Act, the USAF currently (2019) uses INRMPs to manage and protect natural resources on installations. The INRMP that addresses Wake includes components that cover biosecurity and pest management. These are long-term planning documents to guide Department of Defense (DOD) natural resource managers in the management of natural resources to support installation missions while protecting and enhancing resources for multiple uses and biological integrity (U.S. Department of Defense, 2018; U.S. Air Force, 2020). The initial plan introduced the goal to “bring together and integrate all management activities in a way that sustains, promotes, and restores the health and integrity of ecosystems and that enhances the human environment on Wake Atoll” (Foothill Engineering Consultants, Inc., written commun., 2000). The 2008 INRMP identified the need for an invasive species risk assessment (U.S. Air Force, written commun., 2008).

Invasive/pest species are recognized as one of the greatest threats to ecosystems and economies (Vitousek and others, 1997; Warziniack and others, 2021). Biosecurity is thus a concern at several scales from global to local, and to address this issue, prevention and control policies have been and continue to be improved at several levels of government (Ricciardi and others, 2020; Rawluk and others, 2021). A biosecurity plan is an effective tool for identifying and addressing non-native, potentially invasive species problems and concerns (Matos and others, 2018). In 2012, the USAF, with support from private consultants, authored the “Wake Island Biosecurity Management Plan” (U.S. Air Force, unpub. data, 2012). The plan re-defined the container requirements and other elements of USAF shipping to the atoll. The biosecurity plan was updated in 2015 (U.S. Air Force, unpub. data, 2015) and incorporated into the 2017 INRMP as a component plan. The current (2015) biosecurity plan retains a rodent focus. However, some components of the intervention measures within it have potential for inhibiting or intercepting invasive species other than rodents. The INRMP calls for this plan to be updated periodically. In 2017, the U.S. Air Force issued funds to the U.S. Geological Survey (USGS) to update the biosecurity plan, create a current (2019) flora and fauna species identification index, and do container evaluations for the presence of potential invasives. The current (2019) biosecurity protocols used for prevention were evaluated (S.A. Hathaway, C.S. Brehme, and R.N. Fisher, U.S. Geological Survey; J.C. Molden, U.S. Fish and Wildlife Service; R. Peck, Hawai`i Cooperative Studies Unit, University of Hawai`i at Hilo; and K.R. Rex, National Oceanic and Atmospheric Administration, unpub. data, 2022), and new biodiversity surveys were completed for terrestrial vegetation and arthropods and included the first formal reptile surveys. Results from field efforts add to existing knowledge and may identify new species arrivals to Wake.

One goal of this project was to update and compile established species information for the atoll and create species identification guides for the three taxonomic groups surveyed. We made these flora and fauna species identification guides by compiling results of the recent (2019) and historical surveys. The guides can be used as resident desktop references, as a baseline for assessing future natural resource surveys, and to assist with guiding management actions. We refer herein to biosecurity and integrated pest management plan materials, which we created simultaneously to inform current (2019) biosecurity and to identify some of the top invasive species at Wake (Hathaway and others, 2022). This study was done in cooperation with the USAF, and surveys were performed for the 611th Civil Engineer Squadron Natural Resources Program, ACES PROJECT #YGFZ170002 under agreement number F2MUAA7116GW02 between the USAF and the USGS-Western Ecological Research Center.

A. Methods

A. Results

We identified more than 450 species of terrestrial plants, arthropods, and reptiles that have been recorded at Wake (table A1, see chapters B, C, and D for plants, arthropods, and reptiles, respectively). There have been 229 vascular plant species documented during past and current (2019) surveys; 20 are considered native, and 1 is endemic to Wake, whereas 209 are nonnative (table A1). In 2019, a total of 153 plant species were recorded: 19 native and 134 nonnative; 15 were newly reported nonnative species. One native and 75 nonnative plant species previously reported at Wake were not observed in 2019.

Between 221 and 237 total arthropod species have been recorded at Wake. Varying levels of identification impeded comparisons across surveys; therefore, an exact assessment of how many species in total have actually been recorded could not be made. Also, given that reasonable assessment of species provenance has not been possible (see chapter C, “Wake Atoll 2019 Arthropod Species Survey Report and Field Guide”), we could not clearly distinguish which species should be considered native or nonnative to Wake. Between 140 and 156 species had not previously been reported for Wake, and between 48 and 64 species previously recorded were not observed in 2019.

Nine reptile species have been reported at Wake over time; four of these we consider to be native. Of these reptile species, we observed three native and one nonnative lizard species in 2019. We also obtained photographic evidence of one nonnative snake species in 2017. We did not directly detect this species ourselves in the field in 2019.

A. Discussion

As summarized herein, there are 20 terrestrial plant and 4 terrestrial reptile species considered native to Wake. Although there are undoubtedly terrestrial arthropods that are native to Wake, determining with confidence which species are native is beyond the scope of this study. We deduce there have been up to 451 nonnative terrestrial plant (209), arthropod (up to 237), and reptile (5) species recorded on Wake (table A1). About 7 percent (15) of all nonnative plants and up to about 70 percent (156) of arthropod species detected in 2019 had not been previously recorded. This finding may indicate that introductions of new species, particularly arthropods, are ongoing. However, given that many of these species are likely uncommon and patchily distributed, and given the brevity of these surveys, some or even many of these species may have been present previously but not observed. Conversely, it also is possible that some species detected during our surveys were newly introduced and had not yet established or been able to establish. Likewise, approximately 39 percent of nonnative plant species and up to 29 percent of arthropod species were previously recorded but not observed in 2019. Previously unrecorded species of reptiles were not detected in 2019. However, the previously recorded common house gecko (Hemidactylus frenatus), along with various plant seeds and arthropods detected in shipping containers sent to Wake in 2018 (S.A. Hathaway, U.S. Geological Survey; J.C. Molden, U.S. Fish and Wildlife Service; and K.R. Rex, National Oceanic and Atmospheric Administration, unpub. data, 2022), indicates that continued introductions of some established species does happen.

Because of time constraints, some HMUs were less thoroughly assessed than others, and not all HMUs were examined. However, surveys were as representative as time and access permitted; surveying broadly across the atoll, including multiple HMUs on each of the three islets, and focusing on areas we considered most likely to harbor new arrivals. The compilations of historical and 2019 survey data presented here provide a current (2019) baseline for making decisions regarding research, monitoring, planning, and management. These results include examples of recent (since last documented according to sources we report in the chapters herein) changes in biodiversity that point to the importance of robust biosecurity practices.

A. References Cited

Chapter B. Wake Atoll 2019 Plant Species Survey Report and Field Guide

By James D. Jacobi

B. Introduction

The native flora and plant communities reported on Wake Atoll are relatively simple (Fosberg, 1959; Mueller-Dombois and Fosberg, 1998). The extreme isolation of this location has limited the number of plant species able to colonize the very small land surface naturally. The 21 species of vascular plants considered native to Wake are just a small subset of the flora detected across the pan-tropical Pacific islands (Mueller-Dombois and Fosberg, 1998), and one of these, Gossypium stephensii, is endemic to this atoll (Gallagher and others, 2017). Plant diversity on Wake is limited by the relatively uniform dry-arid habitat due to a combination of the porosity of the coral-based substrate (Bryan, 1959) and low annual precipitation, which is approximately 1,015 millimeters (mm) per year (Fosberg, 1959).

In addition to the native flora, many plants have been either purposely or accidentally introduced to the atoll by humans. Although most of these nonnative plants are detected only in cultivation as household or yard ornamentals or in gardens, many introduced species have become naturalized, and a few are considered to be invasive, posing actual or potential threats to maintaining the natural flora and vegetation (D.R. Herbst, B.P. Bishop Museum, unpub. data, 1998; Mueller-Dombois and Fosberg, 1998; U.S. Air Force, unpub. data, 2017).

During summer 2019, a 2-week field survey was done on Wake to assess the status of the plant species and plant communities reported there. This survey was part of a larger project to document the current (2019) status of plant communities, terrestrial reptiles, and arthropods on the atoll and to provide input into the creation of an expanded integrated pest management and biosecurity plan for the Department of Defense.

Specific objectives of the vegetation survey included the following:

B. Methods

Before initiating field work, lists of vascular plant species that had been recorded during previous surveys on Wake were compiled into a relational database. Information in the database includes data source reference and survey dates, current (2019) taxonomic nomenclature, status in the flora (native or introduced), status of the nonnative plants (cultivated or naturalized), and location information on each species on the three islets. Where needed, taxon names were updated to their currently (2019) accepted nomenclature following Roskov and others (2019).

The field survey was done on Wake from May 24 to June 7, 2019. During this time, all areas and habitat types on the three islets were selectivity visited, and plant species were recorded by site and habitat type (fig. B1). Generally, this process involved walking to an arbitrarily chosen representative point within a plant community and documenting all plant species detected in that local vicinity. The Global Positioning System (GPS) coordinates for the site were recorded, as well as information on habitat conditions and other plant communities in that location. Photographs were taken of representative individuals for the recorded species. Each photograph included a date and time stamp, as well as GPS coordinates recorded in decimal degrees so species locations could be accurately mapped.

Information on plants previously recorded on Wake, as well as during the 2019 survey, is presented in tables B1–B3 and appendix B1. The status of species in these tables is identified as follows: “cultivated”—species that were only detected in cultivation and were not reproducing in the wild; “alien invasive”—introduced species that were reported to be established in the wild and considered to be invasive elsewhere (U.S. Forest Service, 2018; Florida Invasive Species Council, 2019; Hawaiʻi-Pacific Weed Risk Assessment, 2019; International Union for Conservation of Nature, 2019; U.S. Department of Agriculture, 2019); “alien naturalized”—species that were reported to be established in the wild but not considered to be invasive; “native”—species that were identified as naturally detected on Wake during previous surveys (Christophersen, 1931; Bryan, 1959; Fosberg, 1959; Fosberg and Sachet, 1969; D.R. Herbst, Bernice Pauahi Bishop Museum, unpub. data, 1998); and “endemic”—species unique only to Wake. In table B2, an introduced species is identified as a threat to biodiversity on Wake if it was reported to be established in the wild and shown to be invasive elsewhere. Also, in table B2, the risk an introduced species poses to biodiversity on Wake ranges from high to medium to low based on the previously mentioned published risk assessments. However, in several cases, the risk category was modified for Wake based on the fact that (1) a species was only detected in cultivation and unlikely to survive outside that level of care; (2) a species with a high risk factor elsewhere currently (2019) has less potential for spread and effects on Wake due to a lack of dispersal agents (for example, seed- or fruit-eating birds); or (3) a species is only in cultivation, and the conditions for its establishment on Wake are minimal due to lack of habitat (for example, waterlily or water hyacinth). Management feasibility in table B2 is identified as “high” for species that are considered to be invasive but not yet widespread and “medium” for species that are invasive but more widespread and require greater effort for control or eradication. The actual cost and capacity needed to control a species will vary depending on the distribution of the species, availability of effective control tools or protocols, and regenerative capability of the species, including persistence of the seedbank. In table B3, species distribution is coded based on the extent of the species in the field in the 2019 survey (widespread or local), and on an estimate of relative abundance (high, medium, low) for each species at that time.

The initial plant species list photo-key that was produced prior to the field survey was updated to include additional species that were identified during the 2019 survey. This photograph key (see the last section of this chapter) includes up to four images of each species and enough detail to generally allow an observer to identify the species in the field. Additionally, each taxon page includes the scientific and common names for the species, its plant family, life form, and status on Wake, as well as information on its past and current (2019) distribution. Species recorded in tables B1–B3, appendix B1, and the “Plant Field Guide to Wake Atoll” section represent only taxa that had clear documentation of their presence on Wake, primarily based on records provided by Christophersen (1931), Bryan (1959), Fosberg and Sachet (Fosberg, 1959; Fosberg and Sachet, 1969), D.R. Herbst Bernice Pauahi Bishop Museum (unpub. data, 1994, 1998), and the 2019 survey. However, to reduce the Field Guide’s size, only species recorded by Herbst in his two surveys and species recorded during the 2019 survey are documented in the photo-key. Common vegetable garden plants and many household ornamentals were also omitted from the Field Guide unless they had high potential to be invasive outside of cultivation.

The results of the current (2019) survey are used to identify several invasive species that resource managers may use on Wake as priorities for integrated pest management. These identifications include some species that already exist on Wake Atoll, as well as others that are not yet reported there but pose a risk to the native ecosystems if they become established (table B4). Descriptions of these species are included in the “Discussion” section, and potential management options for these species are summarized in the biosecurity and integrated pest management plan materials document (Hathaway and others, 2022).

B. Results

A total of 229 vascular plant species have been documented on Wake during previous reporting and 2019 surveys (tables B1–B3; appendix B2; “Plant Field Guide to Wake Atoll” section). Although several naturalists have visited Wake since its discovery and described some of the plants and plant communities detected there (Christophersen, 1931; Bryan, 1959), the first systematic surveys of the atoll were done by Fosberg and Sachet (Fosberg, 1959; Fosberg and Sachet, 1969). Fosberg and Sachet (Fosberg, 1959; Fosberg and Sachet, 1969) recorded 112 species, 18 of which were native and 94 introduced (table B1). Herbst also surveyed this area in 1994 and 1998 and reported 169 species, 18 native and 151 introduced. In both surveys, most of the introduced species were detected only in cultivation.

During the 2019 survey, 153 plant species were recorded. Of this species total, 19 were native and 134 introduced (tables B1–B3). These plant species numbers are similar to those detected by Herbst in 1994 and 1998, although he recorded many more cultivated species than were detected in the 2019 survey (table B1).

Most of the plants recorded during the 2019 survey were detected on Wake Islet (151 species), with lesser amounts detected on Peale (56) and Wilkes (34) Islets (table B3; fig. B2). One of the native species, Heliotropium anomalum (fig. B3), is quite rare and detected in only two locations on Wake Islet. The only endemic species to this atoll, Gossypium stephensii (fig. B4), was detected abundantly on Wake and Peale Islets and on the south part of Wilkes Islet, northwest of the harbor. This species seems to be a successful colonizer of open, previously disturbed habitats (Gallagher and others, 2017). There were 15 species detected during the 2019 survey that had not been previously documented by Fosberg and Sachet (Fosberg, 1959; Fosberg and Sachet, 1969) or D.R. Herbst (Bernice Pauahi Bishop Museum, unpub. data, 1994, 1998); however, many of these species were included in an unpublished species list compiled by M. Waite while he was working on Wake (J. Gilardi, Island Conservation, written commun. May 29, 2019).

Areas sampled in 2019 included most of the Habitat Management Units described in the 2017 Wake Integrated Natural Resources Management Plan (U.S. Air Force, unpub. data, 2017). Voucher specimens were collected for 44 of the species detected during the survey in 2019 to aid with their identification or to document new records (appendix B3). These specimens are deposited in the herbarium at the B.P. Bishop Museum in Honolulu, Hawai‘i.

B. Discussion

Current (2019) Status of Plants and Plant Communities

The low topographic range, meager precipitation, and biogeographic isolation of Wake have all contributed to a flora that is relatively simple, capable of natural recovery from disturbance but also susceptible to change. The dynamic nature of the flora on Wake is a result of both natural perturbations, such as hurricanes or tsunamis, and other factors that include landscape alteration, human disturbance, and effects from introduced species. Primary documented invasive species effects are from introduced rats (Rattus exulans and R. tanezumi; Griffiths and others, 2014; U.S. Air Force, unpub. data, 2017) and from a select number of ecosystem-altering plant species (U.S. Air Force, unpub. data, 2017). It is currently (2019) unclear how introduced invertebrates have affected the native flora and plant communities.

The 2019 survey reported that the dominant native plant communities generally appeared to be maintaining their structure and composition in the lesser disturbed areas throughout the atoll. These communities are relatively simple and include (1) a widespread Heliotropium foertherianum woodland with a native grass and shrub understory (fig. B5); (2) a Pemphis acidula (fig. B6) shrubland that primarily grows along the shoreline, particularly on the lagoon sides of the islets; (3) a mixed Heliotropium woodland with Cordia subcordata (fig. B7) and Pisonia grandis trees (fig. B8); (4) a shrubland dominated by Scaevola sericea (fig. B9), currently (2019) limited in distribution primarily on the southeast tip of Wake Islet; (5) a small community dominated by Sesuvium portulacastrum (fig. B10) that grows around the edges of the few small wetland areas on Wake and Peale Islets; and (6) a very narrow fringe of native grass, primarily Lepturus repens (fig. B11), and scattered native shrubs that form a strand community just above the water’s edge around all the islets. Additionally, there is a unique low-stature native shrubland in the area referred to as the “Bird Sanctuary” on the northwestern part of Wilkes Islet. The area is dominated by the native shrubs Tribulus cistoides and Lepidium bidentatum, but also includes Sida fallax, two Boerhavia species, and the herb Portulaca lutea (fig. B12). This area has been mechanically mowed repeatedly to provide habitat for several species of ground-nesting seabirds (U.S. Air Force, unpub. data, 2017), and native plant species there appear to be able to tolerate this level of disturbance and continue to dominate the vegetation.

The rest of the landscape on the three islets is comprised of a variety of communities that are in various stages of disturbance or recovery from disturbance but primarily dominated by introduced plant species. These communities include grass-dominated areas that are frequently mowed or cleared, such as along roadsides and the sides of the airstrip or in the industrial area on Wake Islet and the harbor area at the southwest tip of Wake. Also included in these communities, are large areas on all the islets that are dominated primarily by ironwood (Casuarina equisetifolia; fig. B13), with little growing under its dense canopy and thick layer of litter on the ground. Additionally, many of the roadsides beyond the regular mowing zone have been invaded by numerous introduced shrubs, including Pluchea carolinensis, Stachytarpheta jamaicensis, Bidens alba, and several introduced grasses.

Most of the introduced plant species detected during the previous and current (2019) surveys on Wake were cultivated plants that were grown either as ornamentals around the residence areas or in vegetable gardens (table B2; figs. B14–B23). The variation in numbers of cultivated species recorded during the three surveys reflects what the residents grew at that time. From 1969 to 2019, there was a slow increase in the number of naturalized and invasive species recorded on Wake (table B1). When all the survey results are combined, 67 introduced species were reported to be naturalized, and 33 of these species are considered invasive in other areas of the Pacific (U.S. Forest Service, 2018; Florida Invasive Species Council, 2019; Hawaiʻi-Pacific Weed Risk Assessment, 2019; U.S. Department of Agriculture, 2019).

Table B1.    

Summary of plant species recorded on Wake Atoll in the 2019 survey or during previous surveys by Fosberg and Sachet (1969) and D.R. Herbst (B.P. Bishop Museum, unpub. data, 1998).

[—, not applicable; I+E, indigenous plus endemic]

Table B1.    Summary of plant species recorded on Wake Atoll in the 2019 survey or during previous surveys by Fosberg and Sachet (1969) and D.R. Herbst (B.P. Bishop Museum, unpub. data, 1998).

Description	Combined lists	Percentage of total	Fosberg and Sachet, 1969	Herbst, 1998	2019 Survey
Total species	229	—	112	169	153
Indigenous	19	8.3	17	17	18
Endemic	1	0.4	1	1	1
Native (I+E)	20	8.7	18	18	19
Alien	209	91.3	94	151	134
Cultivated	140	61.1	51	107	82
Naturalized	36	15.7	22	20	27
Invasive	33	14.4	21	24	25

Table B2.    

List and status of plant species recorded in 2019 or during previous botanical surveys on Wake Atoll.

[Taxonomy follows Roskov and others (2019). Status: Cul, cultivated; A-N, alien naturalized; A-I, alien invasive; E, endemic; Nat, native; A, alien. Impact Description: B, biodiversity; n/a, native species so no impact. Wake risk assessment: H, high; M, medium; L, low; n/a, native species. Management feasibility: H, high, M, medium. Published risk-assessment status: High risk, High risk invasive species; No Assessment, No risk assessment conducted. Published risk-assessment reference: HPWRA, Hawaiʻi-Pacific Weed Risk Assessment, 2019 (www.hpwra.org); FISC database, Florida Invasive Species Council, 2019 (https://www​.fleppc.org/); PIER, Pacific Island Ecosystems at Risk, U.S. Forest Service, 2018 (http://www.hear.org/pier/); USDA-APHIS, U.S. Department of Agriculture Animal and Plant Health Inspection Service; Wake 2019, Wake 2019 Survey. Published risk: N, no assessment; L, low risk; H, high risk; E, evaluate; n/a, not applicable. Abbreviation: —, not determined]

Table B2.    List and status of plant species recorded in 2019 or during previous botanical surveys on Wake Atoll.

Taxonomy				Status and risk
Family	Scientific name	Common name	Function/life form	Status code	Impact type	Wake risk	Management feasibility	Published risk	Risk reference
Monocots
Amaryllidaceae	Allium cepa	Bulb onion, globe onion	Herb	Cul	B	L	—	N	Wake 2019
Amaryllidaceae	Allium fistulosum	Green onion, scallion	Herb	Cul	B	L	—	N	Wake 2019
Amaryllidaceae	Allium tuberosum	Garlic chives	Herb	Cul	B	L	—	N	Wake 2019
Amaryllidaceae	Crinum amabile	Spider lily, Queen Emma crinum	Herb	Cul	B	L	—	N	Wake 2019
Amaryllidaceae	Crinum asiaticum	Spider lily, giant crinum lily	Herb	Cul	B	L	—	L	HPWRA
Amaryllidaceae	Hippeastrum sp.	Amaryllis	Herb	Cul	B	L	—	L	HPWRA
Amaryllidaceae	Hymenocallis littoralis	Beach spider lily	Herb	Cul	B	L	—	N	Wake 2019
Araceae	Caladium bicolor	Caladium, heart of Jesus	Herb	Cul	B	L	—	N	Wake 2019
Araceae	Colocasia esculenta	Taro	Herb	Cul	B	L	—	N	Wake 2019
Araceae	Dieffenbachia seguine	Dumb cane	Herb	Cul	B	M	—	H	HPWRA
Araceae	Epipremnum aureum	Devil's ivy, taro vine	Vine	Cul	B	M	—	H	HPWRA
Araceae	Epipremnum pinnatum	Pothos, taro vine	Vine	Cul	B	M	—	H	FISC
Araceae	Philodendron hederaceum var. oxycardium	Heartleaf philodendron, vilevine	Vine	Cul	B	L	—	N	Wake 2019
Araceae	Philodendron undulatum	Philodendron	Vine	Cul	B	L	—	N	Wake 2019
Araceae	Syngonium auritum	Syngoniurn, arrowhead vine	Vine	Cul	B	L	—	L	HPWRA
Arecaceae	Adonidia merrillii	Manila palm; Christmas palm	Tree	Cul	B	L	—	N	Wake 2019
Arecaceae	Cocos nucifera	Coconut	Tree	A-N	B	M	H	L	HPWRA
Arecaceae	Phoenix sp.	Date palm	Tree	Cul	B	M	—	H	HPWRA
Asparagaceae	Agave americana	Century plant	Shrub	A-I	B	M	—	H	HPWRA
Asparagaceae	Agave angustifolia	Century plant	Shrub	A-N	B	L	—	N	Wake 2019
Asparagaceae	Agave sisalana	Sisal	Shrub	A-I	B	H	H	H	HPWRA
Asparagaceae	Asparagus densiflorus	Asparagus fern	Shrub	Cul	B	M	—	H	HPWRA
Asparagaceae	Chlorophytum comosum	Spider plant	Herb	Cul	B	L	—	H	HPWRA
Asparagaceae	Cordyline fruticosa	ti	Shrub	Cul	B	L	—	E	HPWRA
Asparagaceae	Dracaena reflexa var. angustifolia	Song of India, pleomele	Shrub	Cul	B	L	—	L	HPWRA
Asparagaceae	Sansevieria hyacinthoides	Iguana tail, African bowstring hemp	Herb	A-I	B	M	—	H	FISC
Asparagaceae	Sansevieria trifasciata	Snake plant, mother-in-law's tongue	Herb	Cul	B	M	—	H	HPWRA
Asphodelaceae	Aloe vera	Aloe	Herb	Cul	B	L	—	N	Wake 2019
Bromeliaceae	Ananas comosus	Pineapple	Herb	Cul	B	L	—	L	HPWRA
Bromeliaceae	Nidularium sp.	Nidularium, nest bromeliad	Shrub	Cul	B	L	—	N	Wake 2019
Commelinaceae	Tradescantia pallida	Purple tradescantia, wandering jew	Herb	Cul	B	L	—	N	Wake 2019
Commelinaceae	Tradescantia spathacea	Oyster plant	Herb	Cul	B	M	—	H	HPWRA
Cyperaceae	Cyperus alternifolius	Umbrella sedge	Sedge	Cul	B	L	—	N	Wake 2019
Cyperaceae	Cyperus pumilus	Low flatsedge	Sedge	A-N	B	L	—	N	Wake 2019
Cyperaceae	Cyperus rotundus	Nutgrass, umbrella sedge	Sedge	A-N	B	L	—	N	Wake 2019
Cyperaceae	Fimbristylis cymosa	Tropical fimbry	Sedge	Nat	n/a	n/a	—	n/a	—
Cyperaceae	Fimbristylis dichotoma	Forked fimbry	Sedge	A-N	B	L	—	N	Wake 2019
Hydrocharitaceae	Egeria densa	Brazilian waterweed	Herb	Cul	B	L	—	H	PIER
Musaceae	Musa acuminata	Cavendish banana	Herb	Cul	B	L	—	L	HPWRA
Orchidaceae	Orchid sp.	Orchid species	Herb	Cul	B	L	—	N	Wake 2019
Pandanaceae	Pandanus tectorius	Hala, screwpine	Tree	Cul	B	L	—	N	Wake 2019
Poaceae	Bothriochloa pertusa	Pitted beardgrass	Grass	A-N	B	L	—	N	Wake 2019
Poaceae	Cenchrus brownii	Slim-bristle sandbur	Grass	A-N	B	L	—	N	Wake 2019
Poaceae	Cenchrus echinatus	Sandbur	Grass	A-I	B	H	H	H	PIER
Poaceae	Chloris barbata	Swollen fingergrass	Grass	A-I	B	M	—	H	HPWRA
Poaceae	Cymbopogon citratus	Lemon grass	Grass	Cul	B	L	—	L	HPWRA
Poaceae	Cynodon dactylon	Bermuda grass	Grass	A-I	B	M	—	H	HPWRA
Poaceae	Dactyloctenium aegyptium	Beach wiregrass, crowfoot grass	Grass	A-N	B	L	—	N	Wake 2019
Poaceae	Digitaria ciliaris	Henry's crabgrass, southern crabgrass	Grass	A-N	B	L	—	N	Wake 2019
Poaceae	Digitaria gaudichaudii	Crabgrass	Grass	A-N	B	L	—	N	Wake 2019
Poaceae	Digitaria insularis	Sourgrass	Grass	A-I	B	M	—	H	HPWRA
Poaceae	Eleusine indica	Indian goosegrass, wiregrass	Grass	A-N	B	L	—	N	Wake 2019
Poaceae	Eragrostis amabilis	Japanese lovegrass (syn: E. tenella)	Grass	A-N	B	L	—	N	Wake 2019
Poaceae	Eragrostis minor	Lesser love grass, small stink grass	Grass	A-N	B	L	—	N	Wake 2019
Poaceae	Eragrostis scabriflora	No common name found	Grass	A-N	B	L	—	N	Wake 2019
Poaceae	Eustachys petraea	Pinewoods fingergrass	Grass	A-N	B	L	—	N	Wake 2019
Poaceae	Lepturus repens	Pacific Island thintail	Grass	Nat	n/a	n/a	—	n/a	—
Poaceae	Paspalum scrobiculatum	Ricegrass, Kodo millet (Syn: P. orbiculare)	Grass	A-I	B	M	—	Noxious	USDA-APHIS
Poaceae	Paspalum setaceum	Thin paspalum, fringeleaf paspalum	Grass	A-N	B	L	—	N	Wake 2019
Poaceae	Paspalum vaginatum	Seashore paspalum, biscuit grass	Grass	A-I	B	H	M	H	HPWRA
Poaceae	Setaria verticillata	Bristly foxtail	Grass	A-N	B	L	—	N	Wake 2019
Poaceae	Sorghum bicolor	Sweet sorghum	Grass	Cul	B	L	—	L	HPWRA
Poaceae	Zea mays	Corn	Grass	Cul	B	L	—	N	Wake 2019
Poaceae	Zoysia matrella	Manila grass	Grass	Cul	B	L	—	H	HPWRA
Pontederiaceae	Eichhornia crassipes	Water hyacinth	Aquatic herb	Cul	B	L	—	H	HPWRA
Strelitziaceae	Strelitzia reginae	Bird of paradise	Large herb	Cul	B	L	—	L	HPWRA
Zingiberaceae	Alpinia galanga	Galanga, Thai ginger, blue ginger	Large herb	Cul	B	L	—	L	HPWRA
Zingiberaceae	Alpinia purpurata	Red ginger	Large herb	Cul	B	L	—	E	HPWRA
Zingiberaceae	Hedychium coronarium	White ginger	Large herb	Cul	B	L	—	H	HPWRA
Gymnosperms
Araucariaceae	Araucaria heterophylla	Norfolk Island pine	Tree	Cul	B	L	—	L	HPWRA
Ferns
Polypodiaceae	Phymatosorus scolopendria	Laua'e fern, wart fern	Fern	Cul	B	L	—	E	HPWRA
Psilotaceae	Psilotum nudum	Moa; wisk fern	Fern	A-N	B	L	—	N	Wake 2019
Dicots
Acanthaceae	Pseuderanthemum carruthersii	Carruthers' falseface; yellow-veined eranthemum	Shrub	Cul	B	L	—	L	HPWRA
Acanthaceae	Pseuderanthemum carruthersii var. atropurpureum	Purple false eranthemum	Shrub	Cul	B	L	—	L	HPWRA
Aizoaceae	Sesuvium portulacastrum	Shoreline seapurslane; `akulikuli	Herb	Nat	n/a	n/a	—	n/a	—
Amaranthaceae	Amaranthus blitum	Purple amaranth, sender amaranth	Herb	A-N	B	L	—	N	Wake 2019
Amaranthaceae	Amaranthus dubius	Spleen amaranth, red spinach	Herb	A-N	B	L	—	N	Wake 2019
Amaranthaceae	Amaranthus graecizans	Mediterranean amaranth, short-tepalled pigweed	Herb	A-N	B	L	—	N	Wake 2019
Amaranthaceae	Gomphrena globosa	Bachelor`s button; globe amaranth	Herb	Cul	B	L	—	H	HPWRA
Anacardiaceae	Mangifera indica	Mango	Tree	Cul	B	L	—	L	HPWRA
Anacardiaceae	Spondias pinnata	Wild mango, hog plum	Tree	Cul	B	L	—	N	Wake 2019
Annonaceae	Annona muricata	Soursop	Tree	Cul	B	L	—	L	HPWRA
Annonaceae	Annona squamosa	Sugar apple, custard apple, sweetsop	Tree	Cul	B	L	—	L	HPWRA
Apiaceae	Anethum graveolens	Dill	Herb	Cul	B	L	—	N	Wake 2019
Apiaceae	Coriandrum sativum	Cilantro, coriander, Chinese parsley	Herb	Cul	B	L	—	N	Wake 2019
Apiaceae	Eryngium foetidum	False coriander, serrated coriander	Herb	Cul	B	L	—	N	Wake 2019
Apiaceae	Petroselinum crispum	Parsley	Herb	Cul	B	L	—	L	HPWRA
Apocynaceae	Adenium obesum	Desert rose	Shrub	Cul	B	L	—	L	HPWRA
Apocynaceae	Calotropis gigantea	Crown flower	Shrub	Cul	B	M	—	H	HPWRA
Apocynaceae	Catharanthus roseus	Periwinkle, Madagascar perwinkle	Herb	Cul	B	L	—	H	HPWRA
Apocynaceae	Nerium oleander	Oleander	Shrub	Cul	B	L	—	L	HPWRA
Apocynaceae	Plumeria obtusa	Plumeria, frangipani	Tree	Cul	B	L	—	L	HPWRA
Apocynaceae	Plumeria rubra	Common frangipani, red frangipani	Tree	Cul	B	L	—	L	HPWRA
Araliaceae	Polyscias fruticosa	Ming aralia	Shrub	Cul	B	L	—	L	HPWRA
Araliaceae	Polyscias guilfoylei	Panax, geranium aralia	Shrub	Cul	B	L	—	L	HPWRA
Araliaceae	Polyscias scutellaria	Shield aralia, plum aralia	Shrub	Cul	B	L	—	N	Wake 2019
Araliaceae	Schefflera actinophylla	Octopus tree, umbrella tree	Tree	Cul	B	M	—	H	HPWRA
Asteraceae	Bidens alba	Beggarticks, Spanish needles	Herb	A-I	B	M	—	H	HPWRA
Asteraceae	Erigeron bonariensis	Hairy horseweed, hairy fleabane	Herb	A-I	B	M	—	H	HPWRA
Asteraceae	Erigeron canadensis	Canada fleabane, horseweed	Herb	A-N	B	H	M	N	Wake 2019
Asteraceae	Helianthus annuus	Common sunflower	Herb	Cul	B	M	—	H	HPWRA
Asteraceae	Lactuca sativa	Lettuce	Herb	Cul	B	L	—	N	Wake 2019
Asteraceae	Pluchea carolinensis	Sourbush, fleabane	Shrub	A-I	B	H	M	H	HPWRA
Asteraceae	Pluchea odorata	Camphor-weed, saltmarsh fleabane	Shrub	A-N	B	L	—	N	Wake 2019
Asteraceae	Sonchus oleraceus	Common sowthistle	Herb	A-I	B	L	—	H	HPWRA
Asteraceae	Tagetes erecta	Marigold	Herb	Cul	B	L	—	N	Wake 2019
Asteraceae	Tridax procumbens	Coatbuttons, tridax daisy	Herb	A-I	B	L	—	H	HPWRA
Asteraceae	Zinnia elegans	Garden zinnia	Herb	Cul	B	L	—	N	Wake 2019
Bignoniaceae	Tabebuia aurea	Silver trumpet-tree	Tree	Cul	B	L	—	L	HPWRA
Brassicaceae	Brassica nigra	Black mustard	Herb	Cul	B	L	—	N	Wake 2019
Brassicaceae	Brassica oleracea	Cabbage, kale, kohlrabi, cauliflower, broccoli, etc.	Herb	Cul	B	L	—	N	Wake 2019
Brassicaceae	Lepidium bidentatum	Pepperwort	Herb	Nat	n/a	n/a	—	n/a	—
Brassicaceae	Lobularia maritima	Sweet alyssum or sweet alison	Herb	Cul	B	L	—	H	HPWRA
Brassicaceae	Raphanus sativus	Raddish	Herb	Cul	B	L	—	H	HPWRA
Cactaceae	Nopalea cochenillifera	Cochinilla cactus	Shrub	A-I	B	H	H	H	HPWRA
Cactaceae	Opuntia littoralis	Coastal prickley pear cactus	Shrub	A-N	B	L	—	N	Wake 2019
Caricaceae	Carica papaya	Papaya	Tree	Cul	B	L	—	L	HPWRA
Casuarinaceae	Casuarina equisetifolia	Ironwood; Australian pine tree	Tree	A-I	B	H	H	H	HPWRA
Cleomaceae	Gynandropsis gynandra	African spider-flower	Herb	A-N	B	L	—	N	Wake 2019
Commelinaceae	Terminalia catappa	Indian almond, false kamani	Tree	Cul	B	L	—	L	HPWRA
Convolvulaceae	Cuscuta pentagona	Fiveangled dodder	Vine	A-N	B	M	—	N	—
Convolvulaceae	Ipomoea aquatica	Swamp morning-glory, Chinese watercress	Vine	Cul	B	L	—	N	Wake 2019
Convolvulaceae	Ipomoea batatas	Sweet potato	Vine	Cul	B	L	—	L	HPWRA
Convolvulaceae	Ipomoea pes-caprae subsp. brasiliensis	Beach morning-glory, pohuehue; puhuehue	Vine	Nat	n/a	n/a	—	n/a	—
Convolvulaceae	Ipomoea violacea	Beach moon-flower, heavenlyblue morning-glory	Vine	Nat	n/a	n/a	—	n/a	—
Crassulaceae	Crassula ovata	Jade plant	Herb	Cul	B	L	—	L	HPWRA
Crassulaceae	Kalanchoe daigremontiana	Devil's backbone, alligator plant	Herb	A-I	B	M	—	H	HPWRA
Crassulaceae	Kalanchoe delagoensis	Chandelier plant	Herb	A-I	B	M	—	H	HPWRA
Crassulaceae	Kalanchoe pinnata	Air plant, cathedral bells	Herb	A-I	B	H	H	H	HPWRA
Crassulaceae	Sedum sp.	Stonecrop	Herb	Cul	B	L	—	N	Wake 2019
Crassulaceae	Sempervivum tectorum	Common houseleek	Herb	Cul	B	L	—	N	Wake 2019
Cucurbitaceae	Coccinia grandis	Ivy gourd	Vine	Cul	B	H	H	H	HPWRA
Cucurbitaceae	Cucumis melo	Cantaloupe, muskmelon	Vine	Cul	B	L	—	N	Wake 2019
Cucurbitaceae	Cucurbita pepo	Pumpkin, squash	Vine	Cul	B	L	—	N	Wake 2019
Cucurbitaceae	Momordica charantia	Bitter melon	Vine	Cul	B	M	—	H	HPWRA
Ehretiaceae	Cordia subcordata	Kou	Tree	Nat	n/a	n/a	—	n/a	—
Euphorbiaceae	Codiaeum variegatum	Garden croton or variegated croton	Shrub	Cul	B	L	—	L	HPWRA
Euphorbiaceae	Euphorbia heterophylla var. cyathophora	Dwarf poinsettia, wild poinsettia	Herb	A-I	B	M	—	N	Wake 2019
Euphorbiaceae	Euphorbia hirta	Hairy spurge, garden spurge	Herb	A-N	B	L	—	N	Wake 2019
Euphorbiaceae	Euphorbia hypericifolia	Graceful spurge	Shrub	A-I	B	M	—	H	HPWRA
Euphorbiaceae	Euphorbia lactea	Mottled spurge, frilled fan, candlestick tree	Shrub	Cul	B	M	—	H	HPWRA
Euphorbiaceae	Euphorbia milii	Crown of thorns, Christ plant, or Christ thorn	Shrub	Cul	B	L	—	L	HPWRA
Euphorbiaceae	Euphorbia prostrata	Prostrate purge or prostrate sandmat	Herb	A-I	B	L	—	H	HPWRA
Euphorbiaceae	Euphorbia pulcherrima	Poinsettia; Christmas star	Shrub	Cul	B	L	—	L	HPWRA
Euphorbiaceae	Euphorbia thymifolia	Chickenweed	Herb	A-N	B	L	—	N	Wake 2019
Euphorbiaceae	Euphorbia tirucalli	Firestick, pencil tree, pencil cactus	Shrub	Cul	B	L	—	H	HPWRA
Euphorbiaceae	Euphorbia tithymaloides	Redbird cactus, buck-thorn, Christmas candle	Shrub	Cul	B	L	—	N	Wake 2019
Euphorbiaceae	Jatropha integerrima	Rose-flowered jatropha	Shrub	Cul	B	L	—	L	HPWRA
Euphorbiaceae	Ricinus communis	Castor bean or castor oil plant	Shrub	Cul	B	H	H	H	HPWRA
Fabaceae	Bauhinia sp.	Orchid tree	Tree	Cul	B	M	—	L to H	HPWRA
Fabaceae	Caesalpinia bonduc	Grey nicker, nicker bean, kakalaoa	Vine	Cul	B	M	—	N	—
Fabaceae	Dalea emarginata	Wedgeleaf prairie clover	Herb	A-N	B	L	—	N	Wake 2019
Fabaceae	Delonix regia	Poinciana, flame tree	Tree	Cul	B	L	—	L	HPWRA
Fabaceae	Desmanthus pernambucanus	Wild tantan, prostrate bundleflower, dwarf koa	Shrub	A-I	B	M	—	N	Wake 2019
Fabaceae	Desmanthus virgatus	Wild tantan, prostrate bundleflower, dwarf koa	Shrub	A-I	B	L	—	H	HPWRA
Fabaceae	Gliricidia sepium	Gliricidia	Tree	Cul	B	L	—	L	HPWRA
Fabaceae	Leucaena leucocephala	Koa haole, tangantangan, lead tree	Tree	A-I	B	H	M	H	HPWRA
Fabaceae	Phaseolus coccineus	Snap bean, scarlet runner bean	Vine	Cul	B	L	—	N	Wake 2019
Fabaceae	Phaseolus vulgaris	Common bean, snap bean	Vine	Cul	B	L	—	N	Wake 2019
Fabaceae	Pithecellobium dulce	Opiuma, Manila tamarind	Tree	Cul	B	L	—	H	HPWRA
Fabaceae	Psophocarpus tetragonolobus	Wing bean	Vine	Cul	B	L	—	N	Wake 2019
Fabaceae	Samanea saman	Monkeypod	Tree	Cul	B	L	—	L	HPWRA
Fabaceae	Sesbania grandiflora	Hummingbird tree, scarlet wisteria	Tree	Cul	B	L	—	L	HPWRA
Fabaceae	Tamarindus indica	Tamarind	Tree	Cul	B	L	—	L	HPWRA
Fabaceae	Vigna unguiculata subsp. sesquipedalis	Asparagus bean, yard-long bean	Vine	Cul	B	L	—	N	Wake 2019
Goodeniaceae	Scaevola sericea	Beach naupaka, naupaka kahakai	Shrub	Nat	n/a	n/a	—	n/a	—
Heliotropiaceae	Euploca procumbens var. depressum	Fourspike heliotrope (Heliotropium procumbens)	Herb	A-N	B	L	—	N	Wake 2019
Heliotropiaceae	Heliotropium anomalum	Hinahina, Polynesian heliotrope	Herb	Nat	n/a	n/a	—	n/a	—
Heliotropiaceae	Heliotropium foertherianum	Tree heliotrope, octopus bush	Tree	Nat	n/a	n/a	—	n/a	—
Lamiaceae	Coleus scutellarioides	Coleus	Herb	Cul	B	L	—	N	Wake 2019
Lamiaceae	Mentha spicata	Mint, spearmint	Herb	Cul	B	L	—	H	HPWRA
Lamiaceae	Ocimum basilicum	Sweet basil	Herb	Cul	B	L	—	N	Wake 2019
Lamiaceae	Ocimum tenuiflorum	Holy basil, tulasi	Herb	Cul	B	L	—	N	Wake 2019
Lamiaceae	Vitex trifolia	Blue vitex	Shrub	Cul	B	M	—	H	HPWRA
Lecythidaceae	Barringtonia asiatica	Fish poison tree	Tree	Cul	B	L	—	L	HPWRA
Lythraceae	Pemphis acidula	Pemphis	Shrub	Nat	n/a	n/a	—	n/a	—
Malvaceae	Abutilon indicum subsp. albescens	Indian mallow	Shrub	A-N	B	H	H	N	Wake 2019
Malvaceae	Gossypium stephensii	Wake Island cotton	Shrub	End	n/a	n/a	—	n/a	—
Malvaceae	Hibiscus hybrid	Hibiscus	Shrub	Cul	B	L	—	N	Wake 2019
Malvaceae	Sida ciliaris	Fringed sida	Herb	A-N	B	L	—	—	Wake 2019
Malvaceae	Sida fallax	Ilima	Shrub	Nat	n/a	n/a	—	n/a	—
Malvaceae	Talipariti tiliaceum	Hau, sea hibiscus	Tree	Cul	B	M	—	N	Wake 2019
Malvaceae	Thespesia populnea	Milo	Tree	Cul	B	H	H	H	HPWRA
Malvaceae	Waltheria indica	Uhaloa	Herb	Nat	n/a	n/a	—	n/a	—
Moraceae	Ficus benghalensis	Banyan	Tree	Cul	B	L	—	L	HPWRA
Moraceae	Ficus carica	Edible fig	Tree	Cul	B	L	—	L	HPWRA
Moraceae	Ficus microcarpa	Chinese banyan, Indian laurel fig	Tree	Cul	B	M	—	H	HPWRA
Moraceae	Ficus rubiginosa	Port Jackson fig, rusty fig	Tree	Cul	B	M	—	H	HPWRA
Moraceae	Moringa oleifera	Horseradish tree, drumstick tree	Tree	Cul	B	L	—	L	HPWRA
Myrtaceae	Corymbia citriodora	Lemon-scented gum	Tree	Cul	B	L	—	H	HPWRA
Myrtaceae	Psidium guajava	Common guava, lemon guava	Tree	Cul	B	M	—	H	HPWRA
Nyctaginaceae	Boerhavia albiflora	Spiderling	Herb	Nat	n/a	n/a	—	n/a	—
Nyctaginaceae	Boerhavia coccinea	Scarlet spiderling	Herb	A-N	B	L	—	N	—
Nyctaginaceae	Boerhavia repens	Red spiderling, hogweed	Herb	Nat	n/a	n/a	—	n/a	—
Nyctaginaceae	Bougainvillea spectabilis	Bougainvillea	Shrub	Cul	B	L	—	N	Wake 2019
Nyctaginaceae	Pisonia grandis	Papala kepau	Tree	Nat	n/a	n/a	—	n/a	—
Nymphaeaceae	Nymphaea sp.	Lotus, waterlily	Aquatic herb	Cul	B	L	—	H	HPWRA
Oleaceae	Jasminum sambac	Arabian jasmine, Sambac jasmine	Shrub	Cul	B	L	—	N	Wake 2019
Oleaceae	Noronhia emarginata	Madagascar olive	Shrub	Cul	B	M	—	E	HPWRA
Passifloraceae	Passiflora foetida var. hispida	Passion fruit, scarletfruit passionflower	Vine	A-I	B	H	H	H	HPWRA
Phyllanthaceae	Phyllanthus acidus	Otaheite gooseberry	Shrub	Cul	B	L	—	L	HPWRA
Phyllanthaceae	Phyllanthus amarus	Hurricane weed, carry me seed	Shrub	A-I	B	L	—	H	HPWRA
Polygonaceae	Coccoloba uvifera	Sea grape	Tree	A-I	B	H	H	H	HPWRA
Portulacaceae	Portulaca lutea	Yellow purslane	Herb	Nat	n/a	n/a	—	n/a	—
Portulacaceae	Portulaca oleracea	Purslane, hogweed, pigweed	Herb	A-N	B	L	—	N	Wake 2019
Portulacaceae	Portulaca pilosa subsp. pilosa	Seashore purslane, rose-flowered purslane	Herb	Nat	n/a	n/a	—	n/a	—
Rhamnaceae	Ziziphus mauritiana	Indian jujube, Chinese date	Tree	Cul	B	M	—	H	HPWRA
Rosaceae	Rosa sp.	Rose	Shrub	Cul	B	L	—	N	Wake 2019
Rubiaceae	Gardenia taitensis	Tiare	Shrub	Cul	B	L	—	L	HPWRA
Rubiaceae	Ixora sp.	Ixora	Shrub	Cul	B	L	—	L or E	HPWRA
Rubiaceae	Morinda citrifolia	Noni, Indian-mulberry	Tree	A-I	B	M	—	H	HPWRA
Rubiaceae	Oldenlandia corymbosa	Flat-top mille graines, diamond flower	Herb	A-N	B	L	—	N	Wake 2019
Rutaceae	Citrus hystrix	Kaffir lime, Thai lime	Tree	Cul	B	L	—	E	HPWRA
Rutaceae	Citrus sp.	Citrus	Tree	Cul	B	L	—	L	HPWRA
Sapotaceae	Chrysophyllum cainito	Star apple, cainito	Tree	Cul	B	L	—	L	HPWRA
Sapotaceae	Manilkara zapota	Sapodilla	Tree	Cul	B	L	—	H	HPWRA
Solanaceae	Capsicum annuum	Chili pepper, bell pepper, etc.	Shrub	Cul	B	L	—	L	HPWRA
Solanaceae	Capsicum frutescens	Chili pepper	Shrub	Cul	B	L	—	L	HPWRA
Solanaceae	Nicotiana tabacum	Tobacco	Shrub	Cul	B	M	—	H	HPWRA
Solanaceae	Solanum lycopersicum	Tomato	Shrub	Cul	B	L	—	N	Wake 2019
Solanaceae	Solanum melongena	Egg plant	Shrub	Cul	B	L	—	N	Wake 2019
Solanaceae	Solanum torvum	Turkeyberry, pea eggplant	Shrub	Cul	B	M	—	H	HPWRA
Tetrachondraceae	Polypremnum procumbens	Juniper leaf	Herb	A-N	B	L	—	N	Wake 2019
Urticaceae	Pilea microphylla	Artillery plant	Herb	A-I	B	L	—	H	HPWRA
Urticaceae	Piper sarmentosum	Lolot, wild betel	Shrub	Cul	B	L	—	N	Wake 2019
Verbenaceae	Stachytarpheta jamaicensis	Jamaica vervain, light-blue snakeweed	Shrub	A-I	B	M	—	N	Wake 2019
Verbenaceae	Stachytarpheta urticifolia	Blue rat’s tail, nettleleaf velvetberry	Shrub	A-I	B	M	—	N	Wake 2019
Zygophyllaceae	Tribulus cistoides	Nohu	Shrub	Nat	n/a	n/a	—	n/a	—
Zygophyllaceae	Tribulus terrestris	Puncture vine	Shrub	A-I	B	L	—	H	HPWRA

Table B3.    

Distribution of plant species recorded in 2019 or during previous botanical surveys on Wake Atoll.

[Taxonomy follows Roskov and others (2019). Status: Cul, cultivated; A-N, alien naturalized; A-I, alien invasive; A, alien; E, endemic; Nat, native. Distribution level: W: high, widespread distribution with high abundance; W: mod, widespread distribution with moderate abundance; W: low, widespread distribution with low abundance; L: mod to high, local distribution with moderate to high abundance; L: mod, local distribution with moderate abundance; L: low, local distribution with low abundance; Unknown: not recorded in 2019 survey. Historical distribution references: Fosberg and Sachet, 1969. Wake Island vegetation and flora, 1961–63: Atoll Research Bulletin 1231–15; D.R. Herbst, Bernice Pauahi Bishop Museum, unpub. data, 1998. Abbreviations: X, species was detected; —, not applicable; Y, yes; C, collected]

Table B3.    Distribution of plant species recorded in 2019 or during previous botanical surveys on Wake Atoll.

Taxonomy			2019 distribution								Historical distribution
Family	Scientific name	Status code	Distribution level	Recorded in 2019	Collected in 2019	New in 2019	Wilkes North 2019	Wilkes South 2019	Wake 2019	Peale 2019	Fosberg and Sachet, 1969	Herbst, unpub. data, 1998
Monocots
Amaryllidaceae	Allium cepa	Cul	L: low	X	—	—	—	—	X	—	—	—
Amaryllidaceae	Allium fistulosum	Cul	L: low	X	—	—	—	—	X	—	—	X
Amaryllidaceae	Allium tuberosum	Cul	Unknown	—	—	—	—	—	—	—	—	X
Amaryllidaceae	Crinum amabile	Cul	L: low	X	—	—	—	—	X	—	—	X
Amaryllidaceae	Crinum asiaticum	Cul	L: low	X	—	—	—	—	X	—	—	X
Amaryllidaceae	Hippeastrum sp.	Cul	L: low	X	—	Y	—	—	X	—	—	—
Amaryllidaceae	Hymenocallis littoralis	Cul	Unknown	—	—	—	—	—	—	—	X	X
Araceae	Caladium bicolor	Cul	L: low	X	—	—	—	—	X	—	—	X
Araceae	Colocasia esculenta	Cul	Unknown	—	—	—	—	—	—	—	—	X
Araceae	Dieffenbachia seguine	Cul	L: low	X	—	—	—	—	X	—	—	X
Araceae	Epipremnum aureum	Cul	Unknown	—	—	—	—	—	—	—	X	—
Araceae	Epipremnum pinnatum	Cul	Unknown	—	—	—	—	—	—	—	—	X
Araceae	Philodendron hederaceum var. oxycardium	Cul	Unknown	—	—	—	—	—	—	—	X	—
Araceae	Philodendron undulatum	Cul	Unknown	—	—	—	—	—	—	—	X	X
Araceae	Syngonium auritum	Cul	L: low	X	—	—	—	—	X	—	—	X
Arecaceae	Adonidia merrillii	Cul	L: low	X	—	Y	—	—	X	—	—	X
Arecaceae	Cocos nucifera	A-N	W: mod	X	—	—	—	—	X	X	X	X
Arecaceae	Phoenix sp.	Cul	L: low	X	—	—	—	—	X	—	—	X
Asparagaceae	Agave americana	A-I	L: low	—	—	—	—	—	—	—	—	X
Asparagaceae	Agave angustifolia	A-N	L: low	—	—	—	—	—	—	—	—	X
Asparagaceae	Agave sisalana	A-I	L: low	X	—	—	—	—	X	X	—	X
Asparagaceae	Asparagus densiflorus	Cul	L: low	X	—	—	—	—	X	—	—	X
Asparagaceae	Chlorophytum comosum	Cul	L: low	X	—	—	—	—	X	—	—	X
Asparagaceae	Cordyline fruticosa	Cul	L: low	X	—	—	—	—	X	—	X	X
Asparagaceae	Dracaena reflexa var. angustifolia	Cul	Unknown	—	—	—	—	—	—	—	—	X
Asparagaceae	Sansevieria hyacinthoides	A-I	Unknown	—	—	—	—	—	—	—	X	—
Asparagaceae	Sansevieria trifasciata	Cul	L: low	X	—	—	—	—	X	—	—	—
Asphodelaceae	Aloe vera	Cul	L: low	X	—	—	—	—	X	X	—	X
Bromeliaceae	Ananas comosus	Cul	L: low	X	—	—	—	—	X	—	X	X
Bromeliaceae	Nidularium sp.	Cul	Unknown	—	—	—	—	—	—	—	—	X
Commelinaceae	Tradescantia pallida	Cul	Unknown	—	—	—	—	—	—	—	X	X
Commelinaceae	Tradescantia spathacea	Cul	L: low	X	—	—	—	—	X	—	X	X
Cyperaceae	Cyperus alternifolius	Cul	L: low	X	—	—	—	—	X	—	—	X
Cyperaceae	Cyperus pumilus	A-N	Unknown	—	—	—	—	—	—	—	X	—
Cyperaceae	Cyperus rotundus	A-N	L: low	X	—	—	—	—	X	—	X	X
Cyperaceae	Fimbristylis cymosa	Nat	W: mod	X	C	—	X	X	X	X	X	X
Cyperaceae	Fimbristylis dichotoma	A-N	L: low	X	C	—	—	X	X	—	X	—
Hydrocharitaceae	Egeria densa	Cul	L: low	X	—	Y	—	—	X	—	—	—
Musaceae	Musa acuminata	Cul	L: low	X	—	—	—	—	X	—	—	X
Orchidaceae	Orchid sp.	Cul	L: low	X	—	—	—	—	X	X	—	X
Pandanaceae	Pandanus tectorius	Cul	L: low	X	—	—	—	—	X	—	X	X
Poaceae	Bothriochloa pertusa	A-N	W: mod	X	C	—	—	—	X	X	—	X
Poaceae	Cenchrus brownii	A-N	Unknown	—	—	—	—	—	—	—	X	—
Poaceae	Cenchrus echinatus	A-I	W: mod	X	—	—	—	X	X	X	X	X
Poaceae	Chloris barbata	A-I	L: low	X	C	—	—	—	X	X	X	X
Poaceae	Cymbopogon citratus	Cul	L: low	X	—	—	—	—	X	—	—	X
Poaceae	Cynodon dactylon	A-I	L: low	X	—	—	—	—	X	X	X	X
Poaceae	Dactyloctenium aegyptium	A-N	W: low	X	C	—	X	—	X	X	X	X
Poaceae	Digitaria ciliaris	A-N	Unknown	—	—	—	—	—	—	—	X	—
Poaceae	Digitaria gaudichaudii	A-N	Unknown	—	—	—	—	—	—	—	X	—
Poaceae	Digitaria insularis	A-I	Unknown	—	—	—	—	—	—	—	X	—
Poaceae	Eleusine indica	A-N	L: low	X	C	—	X	—	X	—	X	X
Poaceae	Eragrostis amabilis	A-N	L: low	X	C	—	—	X	X	—	X	X
Poaceae	Eragrostis minor	A-N	Unknown	—	—	—	—	—	—	—	X	—
Poaceae	Eragrostis scabriflora	A-N	W: low	X	C	—	—	X	X	X	—	X
Poaceae	Eustachys petraea	A-N	W: low	X	C	—	X	X	X	X	—	X
Poaceae	Lepturus repens	Nat	W: mod	X	C	—	X	X	X	X	X	X
Poaceae	Paspalum scrobiculatum	A-I	L: low	X	C	—	—	—	X	X	X	—
Poaceae	Paspalum setaceum	A-N	L: low	X	C	—	—	—	X	X	—	X
Poaceae	Paspalum vaginatum	A-I	Unknown	—	—	—	—	—	—	—	X	—
Poaceae	Setaria verticillata	A-N	Unknown	—	—	—	—	—	—	—	X	—
Poaceae	Sorghum bicolor	Cul	Unknown	—	—	—	—	—	—	—	X	X
Poaceae	Zea mays	Cul	Unknown	—	—	—	—	—	—	—	X	—
Poaceae	Zoysia matrella	Cul	L: low	X	—	—	—	—	X	—	—	X
Pontederiaceae	Eichhornia crassipes	Cul	Unknown	—	—	—	—	—	—	—	X	—
Strelitziaceae	Strelitzia reginae	Cul	L: low	X	—	—	—	—	X	—	—	X
Zingiberaceae	Alpinia galanga	Cul	L: low	X	—	—	—	—	X	—	—	X
Zingiberaceae	Alpinia purpurata	Cul	Unknown	—	—	—	—	—	—	—	—	X
Zingiberaceae	Hedychium coronarium	Cul	Unknown	—	—	—	—	—	—	—	—	X
Gymnosperms
Araucariaceae	Araucaria heterophylla	Cul	L: low	X	—	—	—	—	X	—	—	X
Ferns
Polypodiaceae	Phymatosorus scolopendria	Cul	L: low	X	—	—	—	—	X	—	—	X
Psilotaceae	Psilotum nudum	A-N	L: low	X	—	Y	—	—	—	—	—	—
Dicots
Acanthaceae	Pseuderanthemum carruthersii	Cul	L: low	X	—	—	—	—	X	—	X	X
Acanthaceae	Pseuderanthemum carruthersii var. atropurpureum	Cul	L: low	X	—	—	—	—	X	—	X	X
Aizoaceae	Sesuvium portulacastrum	Nat	L: mod to high	X	—	—	—	—	X	X	X	X
Amaranthaceae	Amaranthus blitum	A-N	L: low	X	C	—	—	X	X	—	X	—
Amaranthaceae	Amaranthus dubius	A-N	L: low	X	C	—	—	—	X	—	X	X
Amaranthaceae	Amaranthus graecizans	A-N	L: low	X	—	—	—	—	X	—	X	—
Amaranthaceae	Gomphrena globosa	Cul	Unknown	—	—	—	—	—	—	—	—	X
Anacardiaceae	Mangifera indica	Cul	Unknown	—	—	—	—	—	—	—	—	X
Anacardiaceae	Spondias pinnata	Cul	Unknown	—	—	—	—	—	—	—	—	X
Annonaceae	Annona muricata	Cul	Unknown	—	—	—	—	—	—	—	—	X
Annonaceae	Annona squamosa	Cul	Unknown	—	—	—	—	—	—	—	—	X
Apiaceae	Anethum graveolens	Cul	L: low	X	—	—	—	—	X	—	X	X
Apiaceae	Coriandrum sativum	Cul	L: low	X	—	—	—	—	X	—	—	X
Apiaceae	Eryngium foetidum	Cul	Unknown	—	—	—	—	—	—	—	—	X
Apiaceae	Petroselinum crispum	Cul	Unknown	—	—	—	—	—	—	—	X	—
Apocynaceae	Adenium obesum	Cul	L: low	X	—	Y	—	—	X	X	—	—
Apocynaceae	Calotropis gigantea	Cul	L: low	—	—	—	—	—	—	—	—	X
Apocynaceae	Catharanthus roseus	Cul	L: low	X	—	—	—	—	X	—	X	X
Apocynaceae	Nerium oleander	Cul	L: low	X	—	—	—	—	X	—	X	X
Apocynaceae	Plumeria obtusa	Cul	L: low	X	—	—	—	—	X	—	X	X
Apocynaceae	Plumeria rubra	Cul	L: low	X	—	—	—	—	X	—	—	X
Araliaceae	Polyscias fruticosa	Cul	L: low	X	—	—	—	—	X	—	—	X
Araliaceae	Polyscias guilfoylei	Cul	L: low	X	—	—	—	—	X	—	X	X
Araliaceae	Polyscias scutellaria	Cul	L: low	X	—	—	—	—	X	—	—	X
Araliaceae	Schefflera actinophylla	Cul	L: low	X	—	—	—	—	X	—	X	X
Asteraceae	Bidens alba	A-I	W: mod	X	—	—	—	X	X	—	—	X
Asteraceae	Erigeron bonariensis	A-I	Unknown	—	—	—	—	—	—	—	X	—
Asteraceae	Erigeron canadensis	A-N	W: mod	X	C	—	X	X	X	X	X	X
Asteraceae	Helianthus annuus	Cul	Unknown	—	—	—	—	—	—	—	—	X
Asteraceae	Lactuca sativa	Cul	Unknown	—	—	—	—	—	—	—	X	—
Asteraceae	Pluchea carolinensis	A-I	W: mod	X	C	—	—	X	X	X	—	X
Asteraceae	Pluchea odorata	A-N	Unknown	—	—	—	—	—	—	—	X	—
Asteraceae	Sonchus oleraceus	A-I	Unknown	—	—	—	—	—	—	—	X	—
Asteraceae	Tagetes erecta	Cul	Unknown	—	—	—	—	—	—	—	—	X
Asteraceae	Tridax procumbens	A-I	W: low	X	—	—	—	—	X	X	—	X
Asteraceae	Zinnia elegans	Cul	Unknown	—	—	—	—	—	—	—	—	X
Bignoniaceae	Tabebuia aurea	Cul	L: low	X	C	Y	—	—	X	—	—	—
Brassicaceae	Brassica nigra	Cul	L: low	X	C	—	—	—	X	—	—	X
Brassicaceae	Brassica oleracea	Cul	L: low	X	—	—	—	—	X	—	X	—
Brassicaceae	Lepidium bidentatum	Nat	L: mod to high	X	C	—	X	—	—	X	X	X
Brassicaceae	Lobularia maritima	Cul	Unknown	—	—	—	—	—	—	—	—	X
Brassicaceae	Raphanus sativus	Cul	Unknown	—	—	—	—	—	—	—	X	X
Cactaceae	Nopalea cochenillifera	A-I	L: low	X	—	—	—	—	X	X	—	X
Cactaceae	Opuntia littoralis	A-N	L: low	X	—	—	—	—	—	X	—	X
Caricaceae	Carica papaya	Cul	L: low	X	—	—	—	—	X	—	X	X
Casuarinaceae	Casuarina equisetifolia	A-I	W: high	X	—	—	X	X	X	X	X	X
Cleomaceae	Gynandropsis gynandra	A-N	L: low	X	C	—	—	—	X	X	—	X
Commelinaceae	Terminalia catappa	Cul	L: low	X	—	—	—	—	X	—	X	X
Convolvulaceae	Cuscuta pentagona	A-N	Unknown	—	—	—	—	—	—	—	—	X
Convolvulaceae	Ipomoea aquatica	Cul	L: low	X	—	—	—	—	X	—	—	X
Convolvulaceae	Ipomoea batatas	Cul	Unknown	—	—	—	—	—	—	—	X	—
Convolvulaceae	Ipomoea pes-caprae subsp. brasiliensis	Nat	L: mod to high	X	—	—	—	X	X	X	X	X
Convolvulaceae	Ipomoea violacea	Nat	L: mod	X	—	—	X	X	X	X	X	X
Crassulaceae	Crassula ovata	Cul	Unknown	—	—	—	—	—	—	—	—	X
Crassulaceae	Kalanchoe daigremontiana	A-I	Unknown	—	—	—	—	—	—	—	—	X
Crassulaceae	Kalanchoe delagoensis	A-I	L: low	X	—	—	—	—	X	—	—	X
Crassulaceae	Kalanchoe pinnata	A-I	L: low	X	—	—	—	—	X	—	X	X
Crassulaceae	Sedum sp.	Cul	Unknown	—	—	—	—	—	—	—	—	X
Crassulaceae	Sempervivum tectorum	Cul	Unknown	—	—	—	—	—	—	—	X	—
Cucurbitaceae	Coccinia grandis	Cul	L: low	X	—	—	—	—	X	—	—	X
Cucurbitaceae	Cucumis melo	Cul	L: low	X	—	—	—	—	X	—	X	X
Cucurbitaceae	Cucurbita pepo	Cul	Unknown	—	—	—	—	—	—	—	X	—
Cucurbitaceae	Momordica charantia	Cul	Unknown	—	—	—	—	—	—	—	—	X
Ehretiaceae	Cordia subcordata	Nat	W: mod	X	—	—	X	—	X	X	X	X
Euphorbiaceae	Codiaeum variegatum	Cul	L: low	X	—	—	—	—	X	—	X	X
Euphorbiaceae	Euphorbia heterophylla var. cyathophora	A-I	L: low	X	—	—	—	—	X	X	X	X
Euphorbiaceae	Euphorbia hirta	A-N	W: mod	X	C	—	X	X	X	X	X	X
Euphorbiaceae	Euphorbia hypericifolia	A-I	W: low	X	C	—	—	X	X	X	X	X
Euphorbiaceae	Euphorbia lactea	Cul	Unknown	—	—	—	—	—	—	—	—	X
Euphorbiaceae	Euphorbia milii	Cul	Unknown	—	—	—	—	—	—	—	—	X
Euphorbiaceae	Euphorbia prostrata	A-I	L: low	X	—	—	—	—	X	—	X	X
Euphorbiaceae	Euphorbia pulcherrima	Cul	Unknown	—	—	—	—	—	—	—	X	—
Euphorbiaceae	Euphorbia thymifolia	A-N	L: low	X	C	—	—	—	X	—	X	X
Euphorbiaceae	Euphorbia tirucalli	Cul	Unknown	—	—	—	—	—	—	—	X	X
Euphorbiaceae	Euphorbia tithymaloides	Cul	Unknown	—	—	—	—	—	—	—	X	X
Euphorbiaceae	Jatropha integerrima	Cul	L: low	X	—	—	—	—	X	—	—	X
Euphorbiaceae	Ricinus communis	Cul	Unknown	—	—	—	—	—	—	—	X	—
Fabaceae	Bauhinia sp.	Cul	L: low	X	—	—	—	—	X	—	X	—
Fabaceae	Caesalpinia bonduc	Cul	Unknown	—	—	—	—	—	—	—	—	X
Fabaceae	Dalea emarginata	A-N	L: low	X	C	Y	—	—	X	—	—	—
Fabaceae	Delonix regia	Cul	L: low	X	—	—	—	—	X	—	—	X
Fabaceae	Desmanthus pernambucanus	A-I	L: low	X	C	—	—	—	X	X	—	X
Fabaceae	Desmanthus virgatus	A-I	L: low	X	C	—	—	—	X	—	X	—
Fabaceae	Gliricidia sepium	Cul	L: low	X	C	Y	—	—	X	—	—	—
Fabaceae	Leucaena leucocephala	A-I	L: mod to high	X	—	—	—	X	X	X	X	X
Fabaceae	Phaseolus coccineus	Cul	Unknown	—	—	—	—	—	—	—	X	—
Fabaceae	Phaseolus vulgaris	Cul	L: low	X	—	—	—	—	X	—	X	—
Fabaceae	Pithecellobium dulce	Cul	L: low	X	—	—	—	—	X	X	—	X
Fabaceae	Psophocarpus tetragonolobus	Cul	Unknown	—	—	—	—	—	—	—	—	X
Fabaceae	Samanea saman	Cul	L: low	X	—	Y	—	—	X	—	—	—
Fabaceae	Sesbania grandiflora	Cul	L: low	X	—	—	—	—	X	X	—	X
Fabaceae	Tamarindus indica	Cul	L: low	X	—	—	—	—	X	X	—	X
Fabaceae	Vigna unguiculata subsp. sesquipedalis	Cul	Unknown	—	—	—	—	—	—	—	—	X
Goodeniaceae	Scaevola sericea	Nat	L: mod to high	X	—	—	—	X	X	—	X	X
Heliotropiaceae	Euploca procumbens var. depressum	A-N	W: mod	X	C	—	—	X	X	X	X	X
Heliotropiaceae	Heliotropium anomalum	Nat	L: low	X	—	—	—	—	X	—	X	X
Heliotropiaceae	Heliotropium foertherianum	Nat	W: high	X	—	—	X	X	X	X	X	X
Lamiaceae	Coleus scutellarioides	Cul	Unknown	—	—	—	—	—	—	—	X	—
Lamiaceae	Mentha spicata	Cul	L: low	X	—	Y	—	—	X	—	—	—
Lamiaceae	Ocimum basilicum	Cul	Unknown	—	—	—	—	—	—	—	—	X
Lamiaceae	Ocimum tenuiflorum	Cul	L: low	X	—	—	—	—	X	—	—	X
Lamiaceae	Vitex trifolia	Cul	L: low	X	C	—	—	—	X	X	X	—
Lecythidaceae	Barringtonia asiatica	Cul	L: low	X	—	—	—	—	X	—	—	X
Lythraceae	Pemphis acidula	Nat	W: high	X	—	—	X	X	X	X	X	X
Malvaceae	Abutilon indicum subsp. albescens	A-N	W: mod	X	C	—	—	—	X	X	X	X
Malvaceae	Gossypium stephensii	End	W: mod	X	—	—	—	X	X	X	X	X
Malvaceae	Hibiscus hybrid	Cul	L: low	X	—	—	—	—	X	X	X	X
Malvaceae	Sida ciliaris	A-N	L: low	X	C	Y	—	—	X	—	—	—
Malvaceae	Sida fallax	Nat	W: mod	X	—	—	X	X	X	X	X	X
Malvaceae	Talipariti tiliaceum	Cul	L: low	X	C	—	—	—	X	—	—	X
Malvaceae	Thespesia populnea	Cul	L: low	X	—	—	—	—	X	X	X	X
Malvaceae	Waltheria indica	Nat	W: mod	X	—	—	—	X	X	X	—	X
Moraceae	Ficus benghalensis	Cul	L: low	X	—	Y	—	—	X	—	—	—
Moraceae	Ficus carica	Cul	L: low	X	—	—	—	—	X	—	X	X
Moraceae	Ficus microcarpa	Cul	L: low	X	—	—	—	—	X	X	—	X
Moraceae	spondias pinnata	Cul	Unknown	—	—	—	—	—	—	—	X	—
Moraceae	Moringa oleifera	Cul	Unknown	—	—	—	—	—	—	—	—	X
Myrtaceae	Corymbia citriodora	Cul	Unknown	—	—	—	—	—	—	—	X	—
Myrtaceae	Psidium guajava	Cul	L: low	X	—	—	—	—	X	—	—	X
Nyctaginaceae	Boerhavia albiflora	Nat	L: low	X	C	—	—	—	—	X	—	—
Nyctaginaceae	Boerhavia coccinea	A-N	W: mod	X	C	Y	—	—	X	—	—	—
Nyctaginaceae	Boerhavia repens	Nat	W: mod	X	C	—	X	—	X	—	X	X
Nyctaginaceae	Bougainvillea spectabilis	Cul	L: low	X	—	—	—	—	X	X	X	X
Nyctaginaceae	Pisonia grandis	Nat	L: mod to high	X	—	—	X	—	X	X	X	X
Nymphaeaceae	Nymphaea sp.	Cul	L: low	X	—	—	—	—	X	—	—	X
Oleaceae	Jasminum sambac	Cul	L: low	X	—	—	—	—	X	—	—	X
Oleaceae	Noronhia emarginata	Cul	Unknown	—	—	—	—	—	—	—	—	X
Passifloraceae	Passiflora foetida var. hispida	A-I	L: mod	X	C	—	—	X	X	—	X	X
Phyllanthaceae	Phyllanthus acidus	Cul	L: low	X	—	—	—	—	X	—	—	X
Phyllanthaceae	Phyllanthus amarus	A-I	W: mod	X	—	—	—	X	X	X	X	—
Polygonaceae	Coccoloba uvifera	A-I	L: mod to high	X	—	—	—	—	X	X	X	X
Portulacaceae	Portulaca lutea	Nat	L: mod	X	C	—	X	X	X	X	X	X
Portulacaceae	Portulaca oleracea	A-N	W: mod	X	C	—	X	X	X	X	X	X
Portulacaceae	Portulaca pilosa subsp. pilosa	Nat	Unknown	—	—	—	—	—	—	—	X	—
Rhamnaceae	Ziziphus mauritiana	Cul	Unknown	—	—	—	—	—	—	—	—	X
Rosaceae	Rosa sp.	Cul	Unknown	—	—	—	—	—	—	—	—	X
Rubiaceae	Gardenia taitensis	Cul	L: low	X	—	—	—	—	X	—	—	X
Rubiaceae	Ixora sp.	Cul	L: low	X	—	—	—	—	X	—	—	X
Rubiaceae	Morinda citrifolia	A-I	L: low	X	—	—	—	—	X	—	—	X
Rubiaceae	Oldenlandia corymbosa	A-N	L: low	X	C	Y	—	—	X	X	—	—
Rutaceae	Citrus hystrix	Cul	Unknown	—	—	—	—	—	—	—	—	X
Rutaceae	Citrus sp.	Cul	L: low	X	—	—	—	—	X	—	—	X
Sapotaceae	Chrysophyllum cainito	Cul	Unknown	—	—	—	—	—	—	—	X	—
Sapotaceae	Manilkara zapota	Cul	L: low	X	—	—	—	—	X	—	—	X
Solanaceae	Capsicum annuum	Cul	L: low	X	—	—	—	—	X	—	X	X
Solanaceae	Capsicum frutescens	Cul	Unknown	—	—	—	—	—	—	—	X	—
Solanaceae	Nicotiana tabacum	Cul	Unknown	—	—	—	—	—	—	—	X	—
Solanaceae	Solanum lycopersicum	Cul	L: low	X	—	—	—	—	X	—	X	—
Solanaceae	Solanum melongena	Cul	L: low	X	—	—	—	—	X	—	—	X
Solanaceae	Solanum torvum	Cul	L: low	X	C	—	—	—	X	—	—	X
Tetrachondraceae	Polypremnum procumbens	A-N	L: low	X	C	Y	—	—	X	—	—	—
Urticaceae	Pilea microphylla	A-I	L: low	X	—	—	—	—	X	—	—	X
Urticaceae	Piper sarmentosum	Cul	Unknown	—	—	—	—	—	—	—	—	X
Verbenaceae	Stachytarpheta jamaicensis	A-I	W: mod	X	C	—	—	X	X	X	X	X
Verbenaceae	Stachytarpheta urticifolia	A-I	Unknown	—	—	—	—	—	—	—	X	—
Zygophyllaceae	Tribulus cistoides	Nat	L: mod to high	X	C	—	X	—	X	—	X	X
Zygophyllaceae	Tribulus terrestris	A-I	L: low	X	C	—	—	—	X	—	—	X

Table B4.    

List of invasive plant species that could become established on Wake Atoll if introduced.

[—, not applicable]

Table B4.    List of invasive plant species that could become established on Wake Atoll if introduced.

Family	Scientific name	Common name	Function/ life form	Synonyms
Monocots
Poaceae	Cenchrus setaceus (Forssk.) Morrone	Fountaingrass	Grass	Pennisetum setaceum
Poaceae	Cenchrus ciliaris L.	Buffelgrass	Grass	—
Poaceae	Melinis minutiflora P. Beauv.	Molasses grass	Grass	—
Poaceae	Panicum maximum Jacq.	Guinea grass	Grass	Megathyrsus maximus
Dicots
Asteraceae	Chromolaena odorata (L.) R.King and H.Rob.	Devil weed	Herb	—
Asteraceae	Pluchea indica (L.) Less.	Indian fleabane	Shrub	—
Asteraceae	Verbesina encelioides (Cav.) Benth. and Hook.	golden crown-beard	Shrub	—
Clusiaceae	Clusia rosea Jacq.	Autograph tree	Tree	—
Euphorbiaceae	Ricinus communis L.	Castor bean	Herb	—
Fabaceae	Neonotonia wightii (Wight & Arn.) Lackey	Glycine	Vine	—
Fabaceae	Prosopis pallida (Willd.) Kunth	Kiawe, mesquite	Tree	—
Fabaceae	Prosopis juliflora (Sw.) DC.	Mesquite	Tree	—
Verbenaceae	Lantana camara L.	Lantana	Shrub	—

B. References Cited

Appendix B1. Plant Species Recorded from Wake Atoll in 2019

Available at https://doi.org/10.3133/ofr20231066.

Appendix B2. Plant Field Guide to Wake Atoll

Available at https://doi.org/10.3133/ofr20231066.

Appendix B3. Plant Specimens Collected on Wake Atoll in 2019

Available at https://doi.org/10.3133/ofr20231066.

Chapter C. Wake Atoll 2019 Arthropod Species Survey Report and Field Guide

By Robert Peck

C. Introduction

The first systematic survey for terrestrial arthropods on Wake Atoll (hereafter Wake) was led by E.H. Bryan during the 1923 Tanager Expedition. From July 27 to August 5, 1923, Bryan and his colleagues collected and identified 44 species or morpho-species from within 11 arthropod orders (Bryan and others, 1926). After Bryan and others’ publication (1926), at least 23 notes and papers identifying additional specimens collected during the expedition, or possibly at other times, were published between 1928 and 1951 (publications listed in Bryan, 1959).

After the Tanager collection, relatively few additional arthropod species were recorded on Wake—notable among these was Bryan’s (1959) report that three species of mosquitoes were present during 1951: Culex quinquefasciatus, Aedes aegypti, and Aedes sp. (possibly A. scutellaris or A. albopictus). Because of their ability to vector pathogens harmful to humans, these mosquitoes became targets of an eradication attempt (Bryan, 1959). The effort primarily involved eliminating small reservoirs of water (for example, tires, cans, and other potential breeding habitats) and introducing western mosquitofish (Gambusia affinis) into larger bodies of fresh water, including ponds, bomb craters, and cisterns. Bryan (1959) reported that mosquitoes were not detected during his 2.5-day visit on the atoll in 1952, which indicates the eradication effort, or at least considerable control, seemed to have been successful.

Additional findings of arthropods on Wake Atoll include the identification of ectoparasitic mites (Laelaps nuttalli and Radfordia ensifera) and lice (Hoplopleura pacifica) on rats (Reeves and others, 2012) and the presence of the mango flower beetle (Protaetia fusca; Krell and Breidenbaugh, 2016). During 2009, a survey of terrestrial arthropods was done on Wake as part of an ecological monitoring program prior to an attempt to eradicate invasive rats from the atoll (Hebshi and others, 2011). In that study, at least 86 taxa were collected, 14 of which were identified to the species or near-species level. Subsequently, several arthropod taxa were identified during a survey for potential pollinators of plants being considered for propagation and habitat restoration (Center for Environmental Management—Military Lands, unpub. data, 2017). During the pollinator study, 7 species were detected visiting flowers, and 11 were identified from substrates other than flowers.

The objective of our work was to complete a broad survey of arthropods on Wake, which includes the three islets of Peale, Wake, and Wilkes, to provide a more complete understanding of the fauna, identify species that may pose a significant biosecurity risk, and create a photographic guide that can be used by resource managers and researchers as a tool to more easily identify arthropods that are encountered. This work also will provide a benchmark for comparison in future studies. To attain the goals of this project, our time and effort focused on sampling the atoll as extensively as possible rather than attempting to quantify the fauna within and among habitats or mapping distributions of individual species.

C. Methods

Arthropods were sampled from May 25 to June 8, 2019, using a suite of standard sampling methods, including pitfall traps, yellow pan traps, malaise traps, baiting for ants, light traps, litter sampling, yellow sticky card traps, mosquito traps, and collecting by hand (fig. C1). Each method targeted a slightly different sector of the fauna, but there was overlap in many instances. We attempted to survey as much of the atoll as possible, although the focus was on areas most affected by human activity (for example, dorms, operations facilities, storage areas, the airport, the boat harbor, the solid waste accumulation area, and ecologically complex habitats; fig. C2). We primarily surveyed outside habitats, but we also targeted the insides of several closed shipping containers. A brief description of each sampling method used during this study is listed here:

Most of the arthropods were identified by R. Peck by using existing keys, reference material in the entomology collection at the B.P. Bishop Museum, and online searches from reputable websites (for example, https://www.antweb.org). Neal Evenhuis (B.P. Bishop Museum) identified many of the Diptera, and Karl Magnacca (O'ahu Army Natural Resources Program) identified most of the Hymenoptera, except the ants. In several cases, it was not possible to confidently identify a specimen, or series of similar specimens, to the species level. In those cases, the species most closely thought to represent the specimen in question was preceded by an “nr.,” which indicates that it is near, or similar to, that species. In some other instances, specimens could only be identified to the genus, family, or in a few cases, order level.

For each taxon collected, we estimated the relative risk posed to base operations (for example, human health and operational effectiveness) or the ecology of the atoll and the feasibility of successfully managing the risk. Risk assessments were based on the expected effects for each species, whereas management feasibility was based on the likelihood of controlling the effect. These assessments were broadly categorized as low, medium, or high. A wide variety of published sources were used to estimate risks; the Invasive Species Specialist Group (ISSG) Global Invasive Species Database (GISD; International Union for Conservation of Nature, 2019) and Nishida and Evenhuis (2000) represent two of the more comprehensive sources. For many taxa, little or no information was available to guide the assessments. For these species, information from related species was used if available.

C. Results

Overall, 173 species or morpho-species from within at least 29 orders were identified during the survey (table C1; appendix C1). Hymenoptera (ants, bees, and wasps) were most diverse (33 species), followed by Coleoptera (beetles; 30 species), Diptera (flies; 25 species), and Araneae (spiders; 16 species). It was beyond the scope of this report to identify species and their abundances obtained using each collection method, but arthropods were generally collected as expected (see the “Methods” section). For example, flies and wasps were most commonly collected in malaise traps; spiders and true bugs were primarily obtained by collecting directly from vegetation; moths, termites, and some beetles and flies were collected using an ultraviolet light; many ants were attracted to baits; and mites, millipedes, and terrestrial spiders were extracted from litter using Berlese funnels.

To our knowledge, 81 arthropod species or morpho-species from 20 orders were previously documented on Wake (table C2). Most of those taxa appear to have been first collected during the Tanager Expedition (Bryan and others, 1926; Bryan, 1959), although 21 species were reported for the first time during the past 10 years. Overall, at least 17 of the previously documented species were collected during our survey, although it is possible that we detected an additional 16 taxa collected earlier; incomplete levels of identification (by us or by previous researchers) sometimes precluded species-level comparisons among surveys. Therefore, we report 140–156 arthropod species on Wake for the first time. In contrast, 48–64 species eluded us or are no longer present on the atoll.

Hebshi and others (2011) identified about 86 discrete arthropod taxa (in several additional cases it was unclear if taxa listed were different from those already listed), 15 of which were identified to species or near (listed as “nr.”) species level. Of those taxa, we collected as many as nine species. Unfortunately, we were not able to locate the collection described in Hebshi and others (2011; Bishop Museum Accession Number 2010.010), so we were unable to identify their undetermined taxa or compare our specimens to those in their collection.

Shipping containers are a significant biosecurity concern because arthropods that can survive conditions within containers are easily transported between locations. In two accessible containers that housed pallets, cardboard, or other material (fig. C3), we detected one or more of the following arthropods: orange-flanged millipede (Polydesmida: Paradoxosomatidae), juvenile cockroach (Blattodea), silverfish (Zygentoma: Lepismatidae), pholcid spider (Araneae: Pholcidae), isopod (Isopoda), springtail (Collembola: Entomobryidae), pygmy stinkbug (Hemiptera: Cydnidae), and several ant species, including the Singapore ant, the robust crazy ant, and the ghost ant. Each species collected tolerates dark, enclosed locations (for example, pholcids), particularly where moisture may persist, like under cardboard or wooden boards. Holes in the containers may allow some taxa to move freely to the outside, although pholcids, isopods and cockroaches may reside fully within the containers. A robust crazy ant nest (including a queen and her brood) was detected under a cardboard box in one container. Three small flies (not identified) were caught on a yellow sticky card placed in one container. Insects were not collected on a yellow sticky card placed in a second container.

C. Discussion

In natural conditions, the arthropod community detected on a remote, low-lying atoll like Wake would be expected to be relatively depauperate due to the low diversity of habitats and plant species richness. However, arthropod species diversity may increase with human colonization as additional plant species are introduced and the habitat is modified in ways that benefit species that thrive in proximity to humans. During our survey of Wake, we collected about 170 species across much of the three islets that comprise the 655-hectare (ha) atoll, revealing a relatively rich arthropod fauna. For comparison, 115 arthropods were identified on Palmyra Atoll (less than 500 ha; Handler and others, 2007), and about 73 species were identified on Rose Atoll (6.6 ha; Peck and others 2014). In contrast, we detected considerably fewer species than observed on Midway Atoll, which is similar in size to Wake Atoll (627 ha; Nishida and Beardsley, 2002). On Midway, 546 species were reported from 1891 to 1999. The number of arthropods identified on Midway increased dramatically during the past century because only 38 species were collected during the Tanager Expedition (Bryan and others, 1926). By 1960, the number of species identified had increased to 221 (Suehiro, 1960), and 331 species were collected during 1997–99 (Nishida and Beardsley, 2002). The tremendous increase in arthropod species richness over time on Midway was largely attributed to a parallel increase in the diversity of plants that led to an increase in available niches.

It is not surprising that we failed to collect numerous arthropod species that had been reported previously from Wake. Many species can be expected to be uncommon, temporally variable in abundance, or very patchily distributed, making them difficult to collect during a brief survey. For several species, we collected only one individual, indicating that more species could have been identified with additional effort. Similarly, we detected additional species on the day we departed the atoll (at the airport terminal), indicating that more work could have resulted in more species being detected. It also is possible that some species detected by earlier researchers no longer exist on Wake. It is likely that some species became extirpated over time through depredation, competitive displacement, changes in habitat quality, or by other mechanisms. Small islands and islets, such as those that make up Wake Atoll, are particularly susceptible to stochastic events (for example, storms and drought) that sometimes have significant effects on small populations.

Many of the arthropods collected during our survey pose a low level of risk to the biosecurity of Wake Atoll, but several species pose medium to high levels of risk. One important group is ants, which is a suite of species that have increased greatly in diversity since the Tanager Expedition. Most of the ant species we collected are considered tramp species (strongly associated with humans) and are widespread across the Pacific Basin. Overall, we collected 14 ant species that were not reported by Bryan and others (1926). The yellow crazy ant (Anoplolepis gracilipes), big-headed ants (three species of Pheidole), longhorn crazy ant (Paratrechina longicornis), and tropical fire ant (Solenopsis geminata) are significant because they pose considerable risk to the biodiversity of Wake (O’Dowd and others, 2003; Wetterer, 2007; Wetterer, 2008; Wetterer, 2011). The habitation of the yellow crazy ant on the atoll is of particular concern because it has been indicated to have detrimental effects on ground-nesting seabirds (Plentovich and others, 2009; Plentovich and others, 2018). We detected three of the four ant species collected by Bryan and others (1926) during our survey.

A species that is considered to pose a medium-high level of risk to the biodiversity of Wake is the urbicola scale (Pulvinaria urbicola). This herbivorous insect was detected on Pisonia grandis trees and may affect the health of this tree species on the atoll. The urbicola soft scale feeds on leaves and is capable of stressing trees until they eventually die. Many Pisonia stands across the Pacific and Indian Oceans have been negatively affected by the urbicola soft scale insect (Handler and others, 2007; Neumann and others, 2014).

It is difficult to determine the provenance of many terrestrial arthropods on oceanic islands. Although Wake surely supported a native community of insects and other arthropods, generally poor knowledge of native home ranges for most species hinders our ability to know which species are native to the atoll. In many cases, it is easier to determine which species are not native than which species are native. Bryan and others (1926) reported that many of the arthropods that they encountered were detected elsewhere in the South Pacific. Even at that early time, it is likely that many species had been transported to Wake by humans. For example, the three species of ants that Bryan and others identified on Wake are known to be tramp species strongly associated with human movement across the Pacific Basin. Although it was beyond the scope of this survey to identify the arthropods associated with each of the many plant species, it is notable that we collected several Acalles wilkesii on the endemic cotton (Gossypium stephensii). This species also was collected by Bryan and others (1926), and Wake seems to represent the northernmost extent of this Pacific-wide genus of weevils (Zimmerman, 1938). A thorough search of the literature may lead to confident determination of provenance for some species, but that is beyond the scope of our study.