Endangered and Threatened Wildlife and Plants; Proposed Endangered Status for Five Species From American Samoa
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DEPARTMENT OF THE INTERIOR Fish and Wildlife Service 50 CFR Part 17 [Docket No. FWS-R1-ES-2015-0128; 4500030113] RIN 1018-AZ97 Endangered and Threatened Wildlife and Plants; Proposed Endangered Status for Five Species From American Samoa AGENCY:
Fish and Wildlife Service, Interior.
ACTION:
Proposed rule.
SUMMARY:
We, the U.S. Fish and Wildlife Service (Service), propose to list as endangered species two endemic American Samoan land snails, the American Samoa distinct population segment of the friendly ground-dove, the Pacific sheath-tailed bat, (South Pacific subspecies), and the mao, under the Endangered Species Act (Act). If we finalize this rule as proposed, it would extend the Act's protections to these species. The effect of this regulation will be to add these species to the List of Endangered and Threatened Wildlife.
DATES:
We will accept comments received or postmarked on or before December 14, 2015. Comments submitted electronically using the Federal eRulemaking Portal (see ADDRESSES below) must be received by 11:59 p.m. Eastern Time on the closing date. We must receive requests for public hearings, in writing, at the address shown in FOR FURTHER INFORMATION CONTACT by November 27, 2015.
ADDRESSES:
You may submit comments by one of the following methods:
(1) Electronically: Go to the Federal eRulemaking Portal: http://www.regulations.gov . In the Search box, enter FWS-R1-ES-2015-0128, which is the docket number for this rulemaking. Then, in the Search panel on the left side of the screen, under the Document Type heading, click on the Proposed Rules link to locate this document. You may submit a comment by clicking on “Comment Now!”
ing methods:
(1) Electronically: Go to the Federal eRulemaking Portal: http://www.regulations.gov . In the Search box, enter FWS-R1-ES-2015-0128, which is the docket number for this rulemaking. Then, in the Search panel on the left side of the screen, under the Document Type heading, click on the Proposed Rules link to locate this document. You may submit a comment by clicking on “Comment Now!”
(2) By hard copy: Submit by U.S. mail or hand-delivery to: Public Comments Processing, Attn: FWS-R1-ES-2015-0128; Division of Policy, Performance, and Management Programs; U.S. Fish and Wildlife Service; 5275 Leesburg Pike, MS: BPHC; Falls Church, VA 22041.
We request that you send comments only by the methods described above. We will post all comments on http://www.regulations.gov . This generally means that we will post any personal information you provide us (see Public Comments below for more information).
FOR FURTHER INFORMATION CONTACT:
Mary Abrams, Field Supervisor, Pacific Islands Fish and Wildlife Office, 300 Ala Moana Boulevard, Honolulu, HI 96850, by telephone 808-792-9400 or by facsimile 808-792-9581. Persons who use a telecommunications device for the deaf (TDD) may call the Federal Information Relay Service (FIRS) at 800-877-8339.
SUPPLEMENTARY INFORMATION:
Executive Summary
Why we need to publish a rule. Under the Act, if a species is determined to be an endangered or threatened species throughout all or a significant portion of its range, we are required to promptly publish a proposal in the Federal Register and make a determination on our proposal within 1 year. Critical habitat shall be designated, to the maximum extent prudent and determinable, for any species determined to be an endangered or threatened species under the Act. Listing a species as an endangered or threatened species and designations and revisions of critical habitat can only be completed by issuing a rule
al in the Federal Register and make a determination on our proposal within 1 year. Critical habitat shall be designated, to the maximum extent prudent and determinable, for any species determined to be an endangered or threatened species under the Act. Listing a species as an endangered or threatened species and designations and revisions of critical habitat can only be completed by issuing a rule. We intend to publish a separate rule addressing designation of critical habitat for the five species in American Samoa.
This rule proposes the listing of the two American Samoa land snails, Eua zebrina (no common name) and Ostodes strigatus (no common name), the American Samoa distinct population segment (DPS) of the friendly ground-dove ( Gallicolumba stairi ), and two species from American Samoa (extirpated), Western Polynesia, and Melanesia, the Pacific sheath-tailed bat (South Pacific subspecies) ( Emballonura semicaudata semicaudata ) and the mao ( Gymnomyza samoensis ) as endangered species. These five species are candidate species for which we have on file sufficient information on biological vulnerability and threats to support preparation of a listing proposal, but for which development of a listing regulation has been precluded by other higher priority listing activities. This rule reassesses all available information regarding status of and threats to these five species.
The basis for our action. Under the Act, we can determine that a species is an endangered or threatened species based on any of five factors: (A) The present or threatened destruction, modification, or curtailment of its habitat or range; (B) Overutilization for commercial, recreational, scientific, or educational purposes; (C) Disease or predation; (D) The inadequacy of existing regulatory mechanisms; or (E) Other natural or manmade factors affecting its continued existence
endangered or threatened species based on any of five factors: (A) The present or threatened destruction, modification, or curtailment of its habitat or range; (B) Overutilization for commercial, recreational, scientific, or educational purposes; (C) Disease or predation; (D) The inadequacy of existing regulatory mechanisms; or (E) Other natural or manmade factors affecting its continued existence. One or more of the five candidate species face one or more of the following threats:
• Habitat loss and fragmentation or degradation due to agriculture and urban development, nonnative ungulates, and nonnative plants.
• Collection for commercial purposes (snails only).
• Predation by feral cats, rats, nonnative snails, and nonnative flatworms.
• Inadequate existing regulatory mechanisms.
• Small numbers of individuals and populations.
Environmental effects from climate change are likely to exacerbate these threats, and may become a threat to all five species in the future. We will seek peer review. We will seek comments from independent specialists to ensure that our designation is based on scientifically sound data, assumptions, and analyses in accordance with our joint policy on peer review published in the Federal Register on July 1, 1994 (59 FR 34270). We will invite these peer reviewers to comment on our listing proposal. Because we will consider all comments and information received during the comment period, our final determinations may differ from this proposal.
Information Requested
Public Comments
We intend that any final action resulting from this proposed rule will be based on the best scientific and commercial data available and be as accurate and as effective as possible. Therefore, we request comments or information from the public, other concerned governmental agencies, the American Samoa Government (ASG), the scientific community, industry, or any other interested parties concerning this proposed rule
final action resulting from this proposed rule will be based on the best scientific and commercial data available and be as accurate and as effective as possible. Therefore, we request comments or information from the public, other concerned governmental agencies, the American Samoa Government (ASG), the scientific community, industry, or any other interested parties concerning this proposed rule. For the Pacific sheath-tailed bat and the mao, we also request comments or information from the CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) management and scientific authorities or authority competent to issue comparable documentation in the countries of Samoa, Fiji, Tonga, and Vanuatu. We particularly seek comments concerning:
(1) The species' biology, range, and population trends, including:
(a) Biological or ecological requirements of the species, including habitat requirements for feeding, breeding, and sheltering;
(b) Genetics and taxonomy;
(c) Historical and current range including distribution patterns;
(d) Historical and current population levels, and current and projected trends; and
(e) Past and ongoing conservation measures for these species, their habitats, or both.
(2) Factors that that may affect the continued existence of these species, which may include habitat modification or destruction, overutilization, disease, predation, the inadequacy of existing regulatory mechanisms, or other natural or manmade factors.
(3) Biological, commercial trade, or other relevant data concerning any threats (or lack thereof) to these species and existing regulations that may be addressing those threats.
he continued existence of these species, which may include habitat modification or destruction, overutilization, disease, predation, the inadequacy of existing regulatory mechanisms, or other natural or manmade factors.
(3) Biological, commercial trade, or other relevant data concerning any threats (or lack thereof) to these species and existing regulations that may be addressing those threats.
(4) Empirical data or other scientific information describing the specific impacts of climate change on the habitat, life history, and/or ecology of these species, for example, the species' biological response, or likely response, to changes in habitat resulting from climate-change related changes in ambient temperature, precipitation, drought, or storm severity.
(5) Additional information concerning the historical and current status, ranges, distributions, and population sizes of these species, including the locations of any additional populations of these species.
(6) Although we are not proposing to designate critical habitat at this time, we request information about the quality and extent of areas within U.S. jurisdiction ( i.e., in American Samoa) that may qualify as critical habitat for the proposed species. Specifically, we are soliciting the identification of particular areas within the geographical area occupied by these species in American Samoa that include physical or biological features that are essential to the conservation of these species and that may require special management considerations or protection (16 U.S.C. 1532(5)(A)(i))
at may qualify as critical habitat for the proposed species. Specifically, we are soliciting the identification of particular areas within the geographical area occupied by these species in American Samoa that include physical or biological features that are essential to the conservation of these species and that may require special management considerations or protection (16 U.S.C. 1532(5)(A)(i)). Essential features may include, but are not limited to, features specific to individual species' ranges, habitats, and life history characteristics within the following general categories of habitat features: (1) Space for individual growth and for normal behavior; (2) food, water, air, light, minerals, or other nutritional or physiological requirements; (3) cover or shelter; (4) sites for breeding, reproduction and development of offspring; and (5) habitats that are protected from disturbance or are representative of the historical, geographical, and ecological distributions of the species (50 CFR 424.12(b)). Areas outside the geographical area occupied by the species at the time of listing should also be identified, if such areas are essential for the conservation of the species (16 U.S.C. 1532(5)(A)(ii)). Unlike for occupied habitat, such areas are not required to contain physical or biological features essential to the conservation of the species. ESA implementing regulations at 50 CFR 424.12(h) specify that critical habitat shall not be designated within foreign countries or in other areas outside of U.S. jurisdiction. Therefore, we request information only on potential areas of critical habitat within locations under U.S. jurisdiction.
Please include sufficient information with your submission (such as scientific journal articles or other publications) to allow us to verify any scientific or commercial information you include
designated within foreign countries or in other areas outside of U.S. jurisdiction. Therefore, we request information only on potential areas of critical habitat within locations under U.S. jurisdiction.
Please include sufficient information with your submission (such as scientific journal articles or other publications) to allow us to verify any scientific or commercial information you include.
Please note that submissions merely stating support for or opposition to the action under consideration without providing supporting information, although noted, will not be considered in making a determination, as section 4(b)(1)(A) of the Act directs that determinations as to whether any species is a threatened or endangered species must be made “solely on the basis of the best scientific and commercial data available.”
You may submit your comments and materials concerning this proposed rule by one of the methods listed in the ADDRESSES section. We request that you send comments only by the methods described in the ADDRESSES section.
If you submit information via http://www.regulations.gov, your entire submission—including any personal identifying information—will be posted on the Web site. If your submission is made via a hardcopy that includes personal identifying information, you may request at the top of your document that we withhold this information from public review. However, we cannot guarantee that we will be able to do so. We will post all hardcopy submissions on http://www.regulations.gov . Please include sufficient information with your comments to allow us to verify any scientific or commercial information you include.
Comments and materials we receive, as well as supporting documentation we used in preparing this proposed rule, will be available for public inspection on http://www.regulations.gov, or by appointment, during normal business hours, at the U.S. Fish and Wildlife Service, Pacific Islands Fish and Wildlife Office (see FOR FURTHER INFORMATION CONTACT )
ientific or commercial information you include.
Comments and materials we receive, as well as supporting documentation we used in preparing this proposed rule, will be available for public inspection on http://www.regulations.gov, or by appointment, during normal business hours, at the U.S. Fish and Wildlife Service, Pacific Islands Fish and Wildlife Office (see FOR FURTHER INFORMATION CONTACT ).
Public Hearing
Section 4(b)(5) of the Act provides for one or more public hearings on this proposal, if requested. Requests must be received within 45 days after the date of publication of this proposed rule in the Federal Register . Such requests must be sent to the address shown in FOR FURTHER INFORMATION CONTACT . We will schedule public hearings on this proposal, if any are requested, and announce the dates, times, and places of those hearings, as well as how to obtain reasonable accommodations, in the Federal Register and local newspapers at least 15 days before the hearing.
Previous Federal Action
All five species proposed for listing are candidate species. Candidate species are those taxa for which the Service has sufficient information on their biological status and threats to propose them for listing under the Act, but for which the development of a listing regulation has been precluded to date by other higher priority listing activities. The species addressed in this proposed rule are the Pacific sheath-tailed bat, the mao, the American Samoa DPS of the friendly ground-dove, and two American Samoa land snails, Eua zebrina and Ostodes strigatus . The candidate status of all of these species was most recently assessed and reaffirmed in the December 4, 2014, Review of Native Species That Are Candidates for Listing as Endangered or Threatened (CNOR) (79 FR 72450)
proposed rule are the Pacific sheath-tailed bat, the mao, the American Samoa DPS of the friendly ground-dove, and two American Samoa land snails, Eua zebrina and Ostodes strigatus . The candidate status of all of these species was most recently assessed and reaffirmed in the December 4, 2014, Review of Native Species That Are Candidates for Listing as Endangered or Threatened (CNOR) (79 FR 72450).
On May 4, 2004, the Center for Biological Diversity petitioned the Secretary of the Interior to list 225 species of plants and animals, including four of the five candidate species listed above, as endangered or threatened under the provisions of the Act. Since then, we have published our annual findings on the May 4, 2004, petition (including our findings on the candidate species listed above) in the CNORs dated May 11, 2005 (70 FR 24870), September 12, 2006 (71 FR 53756), December 6, 2007 (72 FR 69034), December 10, 2008 (73 FR 75176), November 9, 2009 (74 FR 57804), November 10, 2010 (75 FR 69222), October 26, 2011 (76 FR 66370), November 21, 2012 (77 FR 69994), November 22, 2013 (78 FR 70104), and December 4, 2014 (79 FR 72450). This proposed rule constitutes a further response to the 2004 petition.
In 2014, the Service evaluated the status and threats for the fifth candidate species, the mao. We determined that
Background
Species Addressed in This Proposed Rule
The table below (Table 1) provides the common name, scientific name, listing priority, and range for the species that are the subjects of this proposed rule.
Table 1—Species Addressed in This Proposed Rule Common name Samoan name or other local name Scientific name Listing priority number Range evaluated for listing MAMMALS Pacific sheath-tailed bat (South Pacific subspecies), Beka beka, Peapea vai, Tagiti Emballonura, semicaudata, semicaudata 3 American Samoa, Fiji, Samoa, Tonga, Vanuatu. BIRDS Mao Gymnomyza samoensis 2 American Samoa, Samoa. Friendly (shy) ground-dove, Tuaimeo Gallicolumba stairi 9 American Samoa DPS
ame or other local name Scientific name Listing priority number Range evaluated for listing MAMMALS Pacific sheath-tailed bat (South Pacific subspecies), Beka beka, Peapea vai, Tagiti Emballonura, semicaudata, semicaudata 3 American Samoa, Fiji, Samoa, Tonga, Vanuatu. BIRDS Mao Gymnomyza samoensis 2 American Samoa, Samoa. Friendly (shy) ground-dove, Tuaimeo Gallicolumba stairi 9 American Samoa DPS. SNAILS No common name Eua zebrina 2 American Samoa. No common name Ostodes strigatus 2 American Samoa. The Samoan Archipelago
The Samoan Archipelago consists of a remote chain of 13 islands and 2 atolls in the Pacific Ocean south of the equator. These islands extend more than 298 miles (mi) (480 kilometers (km)) in an east-west orientation between 13 and 15 degrees south latitude, and 168 to 172 degrees west longitude (Goldin 2002, p. 4). The islands date to the early Pleistocene and were formed as hot-spot shield volcanoes, with the older islands located on the western end of the chain (Thornberry-Ehrlich 2008, pp. 16, 28). The archipelago is divided into two political entities, American Samoa, an unincorporated territory of the United States, and the independent nation of Samoa (Craig 2009, p. 5). American Samoa consists of five high islands and two atolls: Tutuila (the largest island; 54 square (sq) mi (140 sq km)); Aunuu (1 sq mi (2 sq km)) off the southeast end of Tutuila; Ofu and Olosega (3.5 sq mi (9 sq km)) separated by a narrow channel now spanned by a bridge; Tau (15 sq mi (39 sq km)); Rose Atoll (1.5 sq mi (4 sq km)), a National Wildlife Refuge) with two uninhabited islands, Rose and Sand; and Swains Island (0.6 sq mi (1.5 sq km)), which is politically part of American Samoa, but geologically and biologically part of the Tokelau archipelago (Goldin 2002, pp. 5-6). These islands and atolls range in elevation from the high peak of Mt. Lata on Tau at 3,170 ft (966 meters (m)) to 4 to 6 ft (1 to 2 m) above sea level (asl) at Rose Atoll
efuge) with two uninhabited islands, Rose and Sand; and Swains Island (0.6 sq mi (1.5 sq km)), which is politically part of American Samoa, but geologically and biologically part of the Tokelau archipelago (Goldin 2002, pp. 5-6). These islands and atolls range in elevation from the high peak of Mt. Lata on Tau at 3,170 ft (966 meters (m)) to 4 to 6 ft (1 to 2 m) above sea level (asl) at Rose Atoll.
American Samoa lies within the tropics, where it is hot, humid, and rainy year-round. The wet season is from October to May, with a slightly cooler and drier season from June through September. Temperatures average about 81.5 degrees Fahrenheit (F) (27 degrees Celsius (C)). Rainfall averages 125 inches (in) (318 centimeters (cm)) annually at lower elevations, but can vary greatly depending upon topography, reaching 300 in (750 cm) or greater annually in the mountain areas. Hurricanes are a common natural disturbance in the Samoan Archipelago, and occur at intervals of 1 to 13 years (Goldin 2002, p. 7).
In 2010, the population of American Samoa totaled 55,519 individuals (U.S. Census 2011, in litt.). Because of the steep topography, most areas of the northern coastline of Tutuila are uninhabited, and most people live on the narrow coastal plain on the southern shore, within several hundred yards of the shoreline. The islanders practice extensive small-scale agriculture on plots inland of villages and in lowland rainforest on slopes that sometimes exceed 45 degrees (Atkinson and Medeiros 2006, p. 4). Before the arrival of Polynesians approximately 3,000 years ago, the whole archipelago, except for recent lava flows or poorly drained areas, was likely covered by rain forest or cloud forest (Mueller-Dombois and Fosberg 1998, p. 360)
xtensive small-scale agriculture on plots inland of villages and in lowland rainforest on slopes that sometimes exceed 45 degrees (Atkinson and Medeiros 2006, p. 4). Before the arrival of Polynesians approximately 3,000 years ago, the whole archipelago, except for recent lava flows or poorly drained areas, was likely covered by rain forest or cloud forest (Mueller-Dombois and Fosberg 1998, p. 360).
Samoa
The independent nation of Samoa (Samoa) is located less than 100 mi (160 km) west of Tutuila Island, American Samoa, and consists of two large inhabited islands, Upolu (424 sq mi (1,100 sq km)) and Savaii (703 sq mi (1,820 sq km)), and 8 small offshore islets, several of which are inhabited. Samoa lies between 13 to 14 degrees south latitude and 170 to 173 degrees west longitude and has a total land area of approximately 1,133 sq mi (2,934 sq km)) (Watling 2001, p. 26). The highest point in Samoa is Mt. Silisili on Savaii at 6,093 ft (1,857 m) asl. As discussed above, the Samoan archipelago is volcanic in origin with the islands sequentially formed in a generally eastern direction by a series of “hot spot” eruptions, starting with Savaii approximately at 2 million years of age (Keating 1992, p. 131).
Kingdom of Tonga
The Kingdom of Tonga (Tonga) is located in the western South Pacific Ocean, approximately 560 mi (900 km) southwest of the Tutuila Island, American Samoa. The archipelago is spread over 500 mi (800 km) in a north-south direction between 15 to 23.5 degrees south latitude and 173 to 177 west degrees longitude (Australian Bureau of Meteorology (BOM) and Commonwealth Scientific and Industrial Research Organization (CSIRO) Australian BOM and CSIRO 2011, Vol. 2, p. 217). Tonga consists of four groups of islands: Tongatapu and Eua in the south, Haapai in the middle, Vavau in the north, and Niaufoou and Niua Toputapu in the far north. The 172 named islands have an area of 289 sq mi (748 sq km)
rees longitude (Australian Bureau of Meteorology (BOM) and Commonwealth Scientific and Industrial Research Organization (CSIRO) Australian BOM and CSIRO 2011, Vol. 2, p. 217). Tonga consists of four groups of islands: Tongatapu and Eua in the south, Haapai in the middle, Vavau in the north, and Niaufoou and Niua Toputapu in the far north. The 172 named islands have an area of 289 sq mi (748 sq km). The islands include high volcanic islands (maximum elevation 3,389 ft (1,033 m) asl), elevated limestone islands and low-lying
Republic of Fiji
The Republic of Fiji (Fiji) is located in the western South Pacific Ocean approximately 777 mi (1250 km) west of Tutuila Island, American Samoa, between 16 to 20 degrees south latitude and 177 degrees east to 178 degrees west longitude. Fiji consists of 322 islands (105 inhabited) and a total land area of 7,078 sq mi (18,333 sq km) (Watling 2001, p. 22). The two largest islands, Viti Levu (4,026 sq mi (10,429 sq km)) and Vanua Levu (2,145 sq mi (5,556 sq km)), account for 87 percent of the total land area and are mountainous and of volcanic origin with peaks up to 4,265 ft (1,300 m) asl (Australian BOM and CSIRO 2011, Vol. 2, p. 77). The other islands consist of small volcanic islands, low-lying atolls, and elevated reefs in the Northern and Southern Lau groups in the east, the centrally located Lomaiviti group, and the Yasawa group in the northwest (Watling 2001, p. 23).
Republic of Vanuatu
The Republic of Vanuatu (Vanuatu) is an archipelago located in the western South Pacific Ocean, approximately 1,500 mi (2,400 km) west of Tutuila Island, American Samoa. Vanuatu lies between 13 to 21 south degrees latitude and 166 to 171 degrees east longitude and includes over 80 islands (about 65 of which are inhabited) with a total land area of 4,707 sq mi (12,190 sq km) (Central Intelligence Agency (CIA) 2013). Larger islands in general are characterized by rugged volcanic peaks and tropical rainforests
500 mi (2,400 km) west of Tutuila Island, American Samoa. Vanuatu lies between 13 to 21 south degrees latitude and 166 to 171 degrees east longitude and includes over 80 islands (about 65 of which are inhabited) with a total land area of 4,707 sq mi (12,190 sq km) (Central Intelligence Agency (CIA) 2013). Larger islands in general are characterized by rugged volcanic peaks and tropical rainforests. The largest island is Espiritu Santo (1,527 sq mi (3,955 sq km)), which also contains the highest peak, Mount Tabwemasana (6,158 ft (1,877 m) asl) (Australia BOM and CSIRO 2011, Vol. 2, p. 245).
Territory of the Wallis and Futuna Islands
The Territory of the Wallis and Futuna Islands (Wallis and Futuna) is an overseas territory of France located approximately 496 mi (799 km) west of Tutuila Island, American Samoa. Wallis and Futuna consists of three main islands (Wallis or Uvea, Futuna, and Alofi) and more than 20 smaller islands, which lie between 13 to 14 south degrees latitude and 176 to 178 west degrees longitude (Watling 2001, pp. 36-37). The land area totals approximately 98 sq mi (255 sq km). Uvea is a low volcanic island with gentle relief, while Futuna and Alofi (uninhabited) are rugged mountainous islands with uplifted coral tiers (Dupon and Beaudou 1986, p. 1; Watling 2001, p. 36). The islands have experienced extensive deforestation due to the continued use of wood as the main fuel source (CIA 2009).
Pacific Sheath-Tailed Bat (South Pacific Subspecies), Emballonura semicaudata ssp. semicaudata, Peapea Vai (American Samoa), Tagiti (Samoa), Beka Beka (Fiji)
The Pacific sheath-tailed bat is a member of the Emballonuridae, an Old World bat family that has an extensive distribution primarily in the tropics (Nowak 1994, pp. 90-91). A Samoan specimen was first described by Peale in 1848 as Vespertilio semicaudatus (Lyon and Osgood 1909, p. 259)
cies), Emballonura semicaudata ssp. semicaudata, Peapea Vai (American Samoa), Tagiti (Samoa), Beka Beka (Fiji)
The Pacific sheath-tailed bat is a member of the Emballonuridae, an Old World bat family that has an extensive distribution primarily in the tropics (Nowak 1994, pp. 90-91). A Samoan specimen was first described by Peale in 1848 as Vespertilio semicaudatus (Lyon and Osgood 1909, p. 259). The species was later included in the genus Emballonura (Temminck 1838; cited in the Integrated Taxonomic Information System (ITIS) 2014) and is now known as Emballonura semicaudata (Smithsonian Institution 1909; Tate and Archbold 1939, p. 8). This species is a small bat. Males have a forearm length of about 1.8 in (45 millimeters (mm)), and weigh approximately 0.2 ounces (oz) (5.5 grams (g)), and females are slightly larger in size and weight (Lemke 1986, p. 744; Nowak 1994, p. 91; Flannery 1995, p. 326; Uyehara and Wiles 2009, p. 5). The Pacific sheath-tailed bat was once common and widespread in Polynesia, eastern Melanesia, and Micronesia and is the only insectivorous bat recorded from a large part of this area (Hutson et al. 2001, p. 138). Sheath-tailed bats are rich brown to dark brown above and paler below (Walker and Paradiso 1983, p. 211). The common name “sheath-tailed bat” refers to the nature of the tail attachment: The tail pierces the tail membrane, and its tip appears completely free on the upper surface of the membrane (Walker and Paradiso 1983, p. 209). The Pacific sheath-tailed bat (all subspecies) is listed as Endangered in the 2015 IUCN (International Union for Conservation of Nature) Red List (Bonaccorso and Allison 2008). Endangered is IUCN's second most severe category of extinction assessment, which equates to a very high risk of extinction in the wild. IUCN criteria include the rate of decline, population size, area of geographic distribution, and degree of population and distribution fragmentation; however, IUCN rankings do not confer any actual protection or management
) Red List (Bonaccorso and Allison 2008). Endangered is IUCN's second most severe category of extinction assessment, which equates to a very high risk of extinction in the wild. IUCN criteria include the rate of decline, population size, area of geographic distribution, and degree of population and distribution fragmentation; however, IUCN rankings do not confer any actual protection or management.
Four subspecies of Pacific sheath-tailed bats are currently recognized: E. s. rotensis, endemic to the Mariana Islands (Guam and the Commonwealth of the Northern Mariana Islands; proposed for listing as endangered in 2014 (79 FR 59363, October 1, 2014)), and referred to here as the Mariana subspecies); E. s. sulcata in Chuuk and Pohnpei; E. s. palauensis in Palau; and E. s. semicaudata in American Samoa, Samoa, Tonga, Fiji, and Vanuatu (Koopman 1997, pp. 358-360; Oyler-McCance et al. 2013, pp. 1,030-1,036), referred to here as the South Pacific subspecies. Recent analysis found notable genetic differences between E. s. rotensis, E. s. palauensis, and E. s. semicaudata, indeed greater differences than typically reported between mammalian subspecies (Oyler-McCance et al. 2013, p. 1,030). Hereafter, “bat” or “Pacific sheath-tailed bat” refers to the South Pacific subspecies unless otherwise noted.
All subspecies of the Pacific sheath-tailed bat appear to be cave-dependent, roosting during the day in a wide range of cave types, including overhanging cliffs, crevices, lava tubes, and limestone caves (Grant 1993, p. 51; Grant et al. 1994, pp. 134-135; Hutson et al. 2001, p. 139; Palmeirim et al. 2005, p. 28). Large roosting colonies appear fairly common in the Palau subspecies, but smaller aggregations may be more typical of at least the Mariana subspecies and perhaps other species of Emballonura (Wiles et al. 1997, pp. 221-222; Wiles and Worthington 2002, pp. 15, 17)
ubes, and limestone caves (Grant 1993, p. 51; Grant et al. 1994, pp. 134-135; Hutson et al. 2001, p. 139; Palmeirim et al. 2005, p. 28). Large roosting colonies appear fairly common in the Palau subspecies, but smaller aggregations may be more typical of at least the Mariana subspecies and perhaps other species of Emballonura (Wiles et al. 1997, pp. 221-222; Wiles and Worthington 2002, pp. 15, 17). The Mariana subspecies, which persists only on the island of Aguiguan (Commonwealth of the Northern Mariana Islands (CNMI)), appears to prefer relatively large caves (Wiles et al. 2009, p. 15 in O'Shea and Valdez 2009). The limestone cave ecosystem of the Mariana subspecies on Aguiguan is characterized by constant temperature, high relative humidity, and no major air movement (O'Shea and Valdez 2009, pp. 77-78). Such basic habitat data are lacking for the South Pacific subspecies of Pacific sheath-tailed bat, but may be important because the alteration of climate conditions has been implicated in the abandonment of roost caves by other bat species (Hutson et al. 2001, p. 101). All subspecies of the Pacific sheath-tailed bat are nocturnal and typically emerge around dusk to forage on flying insects (Hutson et al. 2001, p. 138; Craig et al. 1993, p. 51). The Mariana Islands subspecies forages almost entirely in forests (native and nonnative) near their roosting caves (Esselstyn et al. 2004, p. 307). Other subspecies in Micronesia have been observed foraging beneath the canopy of dense native forest (on Pohnpei) and over town streets (Palau and Chuuk) (Bruner and Pratt 1979, p. 3). Bats and swiftlets ( Aerodramus spp.) are et al. 2001, p. 139; Tarburton 2002, p. 106; Wiles and Worthington 2002, p. 7, Palmeirim et al. 2005, p. 28).
In American Samoa, Amerson et al. (1982, p. 74) estimated a total population of approximately 11,000 Pacific sheath-tailed bats in 1975 and 1976. A precipitous decline of the bat on the island of Tutuila has been documented since 1990 (Grant et al. 1994, p. 134; Koopman and Steadman 1995, pp
l. 2001, p. 139; Tarburton 2002, p. 106; Wiles and Worthington 2002, p. 7, Palmeirim et al. 2005, p. 28).
In American Samoa, Amerson et al. (1982, p. 74) estimated a total population of approximately 11,000 Pacific sheath-tailed bats in 1975 and 1976. A precipitous decline of the bat on the island of Tutuila has been documented since 1990 (Grant et al. 1994, p. 134; Koopman and Steadman 1995, pp. 9-10; Helgen and Flannery 2002, pp. 4-5). Knowles (1988, p. 65) recorded about 200 in 1988, and in 1993, observers caught one bat and saw only three more (Grant et al. 1994, p. 134). A single bat was also observed on two occasions in a small cave north of Alao (Grant et al. 1994, pp. 134-135). Additional small caves and lava tubes have been checked for bats and swiftlets, however, Tutuila is entirely volcanic and does not have the extensive limestone cave systems that provide bat roosting habitat in the Mariana Islands and other Pacific island groups (Grant et al. 1994, p. 135). Two individuals were last observed in the cave at Anapeapea Cove on the north shore of Tutuila in 1998 (Hutson et al. 2001, p. 138). Surveys conducted by the DMWR in 2006 failed to detect the presence of this species (DMWR 2006, p. 53). In an attempt to ascertain whether the species is still extant, DMWR conducted surveys consisting of acoustic sweeps and cave checks on all main islands in 2008 and 2012, and no bats were detected (Fraser et al. 2009, p. 9; U.R. Tulafono 2011, in litt.; DMWR 2013, in litt.). Based on its decline and the lack of detections since it was last seen in 1998, this species is thought to be nearly extirpated (if not already extirpated) in American Samoa (DMWR 2006, p. 54; Uyehara and Wiles 2009, p. 5). DMWR continues to conduct acoustic surveys in search of the Pacific sheath-tailed bat in American Samoa (Miles 2015a, in litt.)
. Tulafono 2011, in litt.; DMWR 2013, in litt.). Based on its decline and the lack of detections since it was last seen in 1998, this species is thought to be nearly extirpated (if not already extirpated) in American Samoa (DMWR 2006, p. 54; Uyehara and Wiles 2009, p. 5). DMWR continues to conduct acoustic surveys in search of the Pacific sheath-tailed bat in American Samoa (Miles 2015a, in litt.).
In Samoa, the Pacific sheath-tailed bat is known from the two main islands of Upolu and Savaii, but the species has experienced a severe decline over the last several decades, and has been observed only rarely since Cyclones Ofa (1990) and Val (1991) (Lovegrove et al. 1992, p. 30; Park et al. 1992, p. 47; Tarburton 2002, pp. 105-108). This species was previously abundant on Upolu with an individual cave estimated to support several thousand individuals (Ollier et al. 1979, pp. 22, 39). A survey of 41 lava tube caves and other locations on Upolu and Savaii conducted from 1994 to 1997 detected a total of 5 individuals at two sites, which had declined to 2 individuals total by the end of the survey (Hutson 2001, p. 139; Tarburton 2002, pp. 105-108, Tarburton 2011, p. 38). In Samoa, the Pacific sheath-tailed bat occupies sea caves and lava tubes located from the coast up to elevations of 2,500 ft (762 m) that range from 49 ft (15 m) to over 2,130 ft (650 m) in length; vary in height and width, number of openings, and degree of branching; and may be subject to rockfalls and flooding during high rain events (Tarburton 2011, pp. 40-49).
In Tonga, the distribution of the Pacific sheath-tailed bat is not well known. It has been recorded on the island of Eua and Niaufoou (Rinke 1991, p. 134; Koopman and Steadman 1995, p. 7), and is probably absent from Ata and Late (Rinke 1991, pp. 132-133). In 2007, ten nights of acoustic surveys on Tongatapu and Eua failed to record any detections of this species (M. Pennay pers. comm. in Scanlon et al. 2013, p. 456)
bution of the Pacific sheath-tailed bat is not well known. It has been recorded on the island of Eua and Niaufoou (Rinke 1991, p. 134; Koopman and Steadman 1995, p. 7), and is probably absent from Ata and Late (Rinke 1991, pp. 132-133). In 2007, ten nights of acoustic surveys on Tongatapu and Eua failed to record any detections of this species (M. Pennay pers. comm. in Scanlon et al. 2013, p. 456). Pennay describes Eua as the place most likely to support the Pacific sheath-tailed bat because of the island's large tracts of primary forest and many rocky outcrops and caves, but he considers the bat to be extremely rare or extirpated from both islands (M. Pennay pers. comm. in Scanlon et al. 2013, p. 456).
In Fiji, the Pacific sheath-tailed bat is distributed throughout the archipelago, on large islands such as Vanua Levu and Taveuni, medium-sized islands in the Lau group (Lakeba, Nayau, Cicia, Vanua Balavu), and small islets such as Yaqeta in the Yasawa group and Vatu Vara and Aiwa in the Lau group (Palmeirim et al. 2005, pp. 31-32). Pacific sheath-tailed bats in Fiji roost in lava tubes and limestone caves of varying length and width, beneath rock outcrops, and in cave-like areas formed by irregularly-shaped boulders located in areas along the coast and up to 6.2 mi (10 km) inland (Palmierim et al. 2007, pp. 1-13). Running water or pools of water are a common occurrence in inland caves with streams running through or coastal caves that are tidally influenced (Palmierim et al. 2007, pp. 1-13). Habitat surrounding roost sites includes undisturbed forest, secondary forest, cultivated areas, and forested cliffs (Palmierim et al. 2007, pp. 1-13). The species was reported as common some decades ago on the small, volcanic island of Rotuma, a Fijian dependency, approximately 372 mi (600 km) from the Fiji archipelago (Clunie 1985, pp. 154-155)
dally influenced (Palmierim et al. 2007, pp. 1-13). Habitat surrounding roost sites includes undisturbed forest, secondary forest, cultivated areas, and forested cliffs (Palmierim et al. 2007, pp. 1-13). The species was reported as common some decades ago on the small, volcanic island of Rotuma, a Fijian dependency, approximately 372 mi (600 km) from the Fiji archipelago (Clunie 1985, pp. 154-155). Although widely distributed, the species clearly has suffered a serious decline since the 1950s as evidenced by a contraction of its range and a decline in density and abundance on the islands where it still occurs (Flannery 1995, p. 327; Palmeirim et al. 2005, p. 31). In 2000 to 2001 bats were absent or present in diminished numbers in many of the caves known previously to be occupied on 30 Fijian islands, and villagers reported that small bats, presumably Pacific sheath-tailed bats, were no longer commonly seen (Palmeirim et al. 2005, p. 31).
The species is predicted to be extirpated or nearly so on Kadavu, Vanua Levu, and Fiji's largest island, Viti Levu, where it was known to be widespread until the 1970s (Palmeirim et al. 2005, p. 31; Scanlon et al. 2013, p. 453). Field observations during the 2000 to 2001 surveys documented a single large colony of several hundred individuals on Yaqeta Island in the Yasawa group and a large colony on Vatu Vara Island in the Lau group, but otherwise only a few to dozens of individuals scattered among caves on small and remote islands in the Lau group (Palmeirim et al. 2005, pp. 55-62). Scanlon et al. 2013 (p. 453) revisited the large cave colony on Yaqeta between 2007 and 2011 and described it as without any evidence of any recent use by bats ( e.g., odor, fresh guano) and probably abandoned. The loss of the Yaqeta colony and the species' overall declining trend across the archipelago led Scanlon et al. 2013 (p. 456) to infer a reduction in population size of greater than 80 percent over the last 10 years
) revisited the large cave colony on Yaqeta between 2007 and 2011 and described it as without any evidence of any recent use by bats ( e.g., odor, fresh guano) and probably abandoned. The loss of the Yaqeta colony and the species' overall declining trend across the archipelago led Scanlon et al. 2013 (p. 456) to infer a reduction in population size of greater than 80 percent over the last 10 years. The most important remaining sites for the protection of this species are likely those on small and mid-sized islands in Lau where bats still occur (Palmeirim et al. 2007, p. 512).
In Vanuatu, the Pacific sheath-tailed bat is known from two museum specimens, one collected in 1929 and one collected before 1878, both on the main island of Espiritu Santo (Helgen and Flannery 2002, pp. 210-211). No subsequent expeditions have recorded sheath-tailed bats, suggesting that this species was either extirpated or perhaps never actually occurred in Vanuatu (Medway and Marshall 1975, pp. 32-33; Hill 1983, pp. 140-142; Flannery 1995, p. 326; Helgen and Flannery 2002, pp. 210-211; Palmeirim et al. 2007, p. 517). For example, Medway and Marshall (1975, p. 453) detected seven other small, insectivorous bats (family Microchiroptera) in Vanuatu, but failed to observe the Pacific sheath-tailed bat, possibly as a result of survey sites and methods. However, the Vanuatu provenance of the two specimens is not in question (Helgen and Flannery 2002, p. 211). The current disjunct distribution of the Pacific sheath-tailed bat (all subspecies) is suggestive of
In summary, the Pacific sheath-tailed bat, once widely distributed across the southwest Pacific islands of American Samoa, Samoa, Tonga, and Fiji, has undergone a significant decline in numbers and contraction of its range. Reports of possible extirpation or extremely low numbers in American Samoa and Samoa, steep population declines in Fiji, and the lack of detections in Tonga and Vanuatu, suggest that the Pacific sheath-tailed bat is vulnerable to extinction throughout its range
st Pacific islands of American Samoa, Samoa, Tonga, and Fiji, has undergone a significant decline in numbers and contraction of its range. Reports of possible extirpation or extremely low numbers in American Samoa and Samoa, steep population declines in Fiji, and the lack of detections in Tonga and Vanuatu, suggest that the Pacific sheath-tailed bat is vulnerable to extinction throughout its range. The remaining populations of the Pacific sheath-tailed bat continue to experience habitat loss from deforestation and development, predation by introduced mammals, and human disturbance of roosting caves, all of which are likely to be exacerbated in the future by the effects of climate change (see Summary of Factors Affecting the Species discussion below). In addition, low population numbers and the breakdown of the metapopulation equilibrium across its range render the remaining populations of Pacific sheath-tailed bat more vulnerable to chance occurrences such as hurricanes.
Summary of Factors Affecting the Pacific Sheath-Tailed Bat
A. The Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range
Habitat Destruction and Modification by Deforestation
Deforestation can cause the destruction and modification of foraging habitat of the Pacific sheath-tailed bat as a result of the loss of cover and reduction of available insect prey. The loss of native plant diversity associated with the conversion of native forests to agriculture and other uses can result in a corresponding reduction in the diversity and number of flying insects (Hespenheide 1975, pp. 84, 96; Waugh and Hails 1983, p. 212; Tarburton 2002, p. 107). Deforestation results from logging, agriculture, and development (Government of Samoa 2001, p. 59; Wiles and Worthington 2002, p. 18) and from hurricanes. Based on the preference of the Mariana subspecies for foraging in forested habitats near their roost caves, Wiles et al. (2011, p
and number of flying insects (Hespenheide 1975, pp. 84, 96; Waugh and Hails 1983, p. 212; Tarburton 2002, p. 107). Deforestation results from logging, agriculture, and development (Government of Samoa 2001, p. 59; Wiles and Worthington 2002, p. 18) and from hurricanes. Based on the preference of the Mariana subspecies for foraging in forested habitats near their roost caves, Wiles et al. (2011, p. 307) predict that past deforestation in the Mariana archipelago may be a principal factor in limiting their current population to the island of Aguiguan, which has healthy native forest. Similarly, in Fiji, most sheath-tailed bat colonies are found roosting in caves in or near good forest ( e.g., closed canopy, native forest) (Palmeirim et al. 2005, pp. 36, 44); however, much of it has been lost on the large Fijian islands (Palmeirim et al. 2007, p. 515).
Deforestation has been extensive and is ongoing across the range of the Pacific sheath-tailed bat. On the island of Tutuila, American Samoa, agriculture and development cover approximately 24 percent of the island and are concentrated in the coastal plain and low-elevation areas where loss of forest is likely to have modified foraging habitat for sheath-tailed bats (American Samoa Community College (ASCC) 2010, p. 13). In Samoa, the amount of forested area declined from 74 to 46 percent of total land area between 1954 and 1990 (Food and Agricultural Organization (FAO) 2005 in litt.). Between 1978 and 1990, 20 percent of all forest losses in Samoa were attributable to logging, with 97 percent of the logging having occurred on Savaii (Government of Samoa 1998 in Whistler 2002, p. 132). Forested land area in Samoa continued to decline at a rate of roughly 2.1 percent or 7,400 ac (3,000 ha) annually from 1990 to 2000 (FAO 2005 in litt.). As a result, there is very little undisturbed, mature forest left in Samoa (Watling 2001, p. 175; FAO 2005 in litt.)
ibutable to logging, with 97 percent of the logging having occurred on Savaii (Government of Samoa 1998 in Whistler 2002, p. 132). Forested land area in Samoa continued to decline at a rate of roughly 2.1 percent or 7,400 ac (3,000 ha) annually from 1990 to 2000 (FAO 2005 in litt.). As a result, there is very little undisturbed, mature forest left in Samoa (Watling 2001, p. 175; FAO 2005 in litt.). Today, only 360 ac (146 ha) of native lowland rainforests (below 2,000 ft or 600 m) remain on Savaii and Upolu as a result of logging, agricultural clearing, residential clearing (including relocation due to tsunami), and natural causes such as rising sea level and hurricanes (Ministry of Natural Resources and Environment (MNRE) 2013, p. 47). On Upolu, direct or indirect human influence has caused extensive damage to native forest habitat (above 2,000 ft or 600 m) (MNRE 2013, p. 13). Although forested, almost all upland forests on Upolu are largely dominated by introduced species today. Savaii still has extensive upland forests, which are for the most part undisturbed and composed of native species (MNRE 2013, p. 40). Although the large Fijian islands still have some areas of native forest, much of it has been lost ( e.g., 17 percent between 1990 and 2000; FAO 2005 in litt.), and commercial logging continues (Palmeirim et al. 2007, p. 515). The best available information does not provide the current status of native forests and rates of forest loss in Tonga or Vanuatu. Native forests are preferred foraging habitat of the Pacific sheath-tailed bat, and deforestation is occurring in Fiji (where the last relatively large population occurs), and in Samoa, and has occurred in American Samoa. Therefore we conclude that habitat destruction and modification by deforestation is a current threat to the species in at least Fiji and Samoa, which comprise roughly 62 percent of the land area, and occupy the center, of the bat's range
c sheath-tailed bat, and deforestation is occurring in Fiji (where the last relatively large population occurs), and in Samoa, and has occurred in American Samoa. Therefore we conclude that habitat destruction and modification by deforestation is a current threat to the species in at least Fiji and Samoa, which comprise roughly 62 percent of the land area, and occupy the center, of the bat's range.
Habitat Destruction and Modification by the Effects of Climate Change
Climate change may have impacts to the habitat of the Pacific sheath-tailed bat. Discussion of these impacts is included in our complete discussion of climate change in the section “E. Other Natural or Manmade Factors Affecting Their Continued Existence,” below.
Conservation Efforts To Reduce Habitat Destruction, Modification, or Curtailment of Its Range
American Samoa
The National Park of American Samoa (NPSA) was established to preserve and protect the tropical forest and archaeological and cultural resources, to maintain the habitat of flying foxes, to preserve the ecological balance of the Samoan tropical forest, and, consistent with the preservation of these resources, to provide for the enjoyment of the unique resources of the Samoan tropical forest by visitors from around the world (Pub. L. 100-571, Pub. L. 100-336). Under a 50-year lease agreement between local villages, the American Samoa Government, and the Federal Government, approximately 8,000 ac (3,240 ha) of forested habitat on the islands of Tutuila, Tau, and Ofu are protected and managed, including suitable foraging habitat for the Pacific sheath-tailed bat (NPSA Lease Agreement 1993).
Samoa
As of 2014, a total of approximately 58,176 ac (23,543 ha), roughly 8 percent of the total land area of Samoa (285,000 ha) was enlisted in terrestrial protected areas, with the majority located in five national parks covering a total of 50,629 ac (20,489 ha), overlapping several sites known to be previously occupied by the bat (Tarburton 2002, pp. 105-107; Tarburton 2011, pp
ement 1993).
Samoa
As of 2014, a total of approximately 58,176 ac (23,543 ha), roughly 8 percent of the total land area of Samoa (285,000 ha) was enlisted in terrestrial protected areas, with the majority located in five national parks covering a total of 50,629 ac (20,489 ha), overlapping several sites known to be previously occupied by the bat (Tarburton 2002, pp. 105-107; Tarburton 2011, pp. 43-46).
Fiji
Fiji currently has 23 terrestrial protected areas covering 188 sq mi (488 sq km) or 2.7 percent of the nation's land area (Fiji Department of Environment 2014, pp. 20-21). Most notably, on Taveuni Island, the Bouma
Summary of Factor A
Based on our review of the best available scientific and commercial information, habitat destruction and degradation by deforestation, as a result of logging and land-clearing for agriculture and other land-uses, is occurring throughout the range of the Pacific sheath-tailed bat. Habitat destruction and modification and range curtailment are current threats to the Pacific sheath-tailed bat that are likely to persist in the future.
B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes
The best available information does not indicate that the Pacific sheath-tailed bat is used for any commercial, recreational, scientific, or educational purpose. As a result, we do not find overutilization for commercial, recreational, scientific, or educational purposes to be a threat to the Pacific sheath-tailed bat.
C. Disease or Predation
Predation by Nonnative Mammals
Predation by nonnative mammals (mammals that occur as a result of introduction by humans) is a factor in the decline of the Pacific sheath-tailed bat throughout its range. Terrestrial predators may be able to take the bat directly from its roosts, which are often in exposed sites such as shallow caves, rock overhangs or cave entrances
t.
C. Disease or Predation
Predation by Nonnative Mammals
Predation by nonnative mammals (mammals that occur as a result of introduction by humans) is a factor in the decline of the Pacific sheath-tailed bat throughout its range. Terrestrial predators may be able to take the bat directly from its roosts, which are often in exposed sites such as shallow caves, rock overhangs or cave entrances. Domestic and feral cats ( Felis catus ) can capture low-flying bats; cats have been documented to wait for bats as they emerge from caves and capture them in flight (Tuttle 1977 in Palmeirim et al. 2005, p. 33; Ransome 1990 in Palmeirim et al. 2005, p. 33; Woods et al. 2003, pp. 178, 188). Consequently, even a few cats can have a major impact on a population of cave-dwelling bats (Palmeirim et al. 2005, p. 34).
Of the predators introduced to Fiji, cats are the most likely to prey on bats (Palmeirim et al. 2005, pp. 33-34). On Cicia Island in the Lau group in Fiji, Palmeirim et al. (2005, p. 34) observed a cat next to the entrance of a cave where Pacific sheath-tailed bats roosted, far from any human settlement. On Lakeba (Lau), a cave that once harbored a large colony of Pacific sheath-tailed bats is now empty and called Qara ni Pusi (cave of the cat; (Palmeirim et al. 2005, p. 34)). Feral cats are also present on Tutuila and on the Manua Islands in American Samoa, (Freifeld 2007, pers. comm.; Arcilla 2015, in litt.). Feral cats have also been documented in Samoa, Tonga, and are likely present in Vanuatu (Atkinson and Atkinson 2000, p. 32; Freifeld 2007, pers. comm.; Arcilla 2015, in litt.).
Rats may also prey on the Pacific sheath-tailed bat. Rats are omnivores and opportunistic feeders and have a widely varied diet consisting of nuts, seeds, grains, vegetables, fruits, insects, worms, snails, eggs, frogs, fish, reptiles, birds, and mammals (Fellers 2000, p. 525; Global Invasive Species Database (GISD) 2011)
Atkinson 2000, p. 32; Freifeld 2007, pers. comm.; Arcilla 2015, in litt.).
Rats may also prey on the Pacific sheath-tailed bat. Rats are omnivores and opportunistic feeders and have a widely varied diet consisting of nuts, seeds, grains, vegetables, fruits, insects, worms, snails, eggs, frogs, fish, reptiles, birds, and mammals (Fellers 2000, p. 525; Global Invasive Species Database (GISD) 2011). Rats are known to prey on non-volant (young that have not developed the ability to fly) bats at roosting sites and can be a major threat to bat colonies (Wiles et al. 2011, p. 306). Of several nonnative rats ( Rattus spp.) found on islands in the Pacific, black rats ( R. rattus ) likely pose the greatest threat to Pacific sheath-tailed bats because of their excellent climbing abilities (Palmeirim 2015, in litt.). Although we lack direct evidence of black rats preying on Pacific sheath-tailed bats, this rat species has had documented, adverse impacts to other colonial species of small bats, such as Townsend's big-eared bat ( Corynorhinus townsendii ) in California (Fellers 2000, pp. 524-525), and several species ( Mystacina spp.) in New Zealand (Daniel and Williams 1984, p. 20). Based on observations of swiftlets, cave-nesting birds that often share bats' roosting caves, smooth rock overhangs in tall caverns can provide nesting surfaces safe from rats, cats, and other predators (Tarburton 2011, p. 38). However, bats roosting in caves with low ledges or those that are filled with debris as a result of rockfalls or severe weather events are likely to either abandon such caves or become more accessible to predators such as rats. Rats have been postulated as a problem for the Mariana subspecies of the Pacific sheath-tailed bat (Wiles et al. 2011, p. 306); their remaining roost sites on Aguiguan appear to be those that are inaccessible to rodents (Wiles and Worthington 2002, p. 18; Berger et al. 2005, p. 144). Nonnative rats are present throughout the range of Pacific sheath-tailed bats (Atkinson and Atkinson 2000, p
rats. Rats have been postulated as a problem for the Mariana subspecies of the Pacific sheath-tailed bat (Wiles et al. 2011, p. 306); their remaining roost sites on Aguiguan appear to be those that are inaccessible to rodents (Wiles and Worthington 2002, p. 18; Berger et al. 2005, p. 144). Nonnative rats are present throughout the range of Pacific sheath-tailed bats (Atkinson and Atkinson 2000, p. 32), and although we lack information about the impact of rats on this species, based on information from other bat species, we consider rats to be predators of this species.
In summary, nonnative mammalian predators such as rats and feral cats are present throughout the range of the Pacific sheath-tailed bat. Predation of related subspecies and other cave-roosting bats by rats and feral cats strongly suggests a high probability of predation of the Pacific sheath-tailed bat. Based on the above information, we conclude that predation by rats and feral cats is a current and future threat to the Pacific sheath-tailed bat throughout its range.
Disease
Disease may contribute to the decline of the Pacific sheath-tailed bat, especially because of the bat's communal roosting habit (Wiles and Worthington 2002, p. 13). Microchiropterans have been severely affected by certain diseases, such as white nose syndrome in North America; therefore, the possibility exists that an undetected disease has led or contributed to the extirpation of this species on several islands (Malotaux 2012a in litt.). However, disease has not been observed either in the Mariana or South Pacific subspecies of Pacific sheath-tailed bat (Palmeirim et al. 2007, p. 517; Wiles et al. 2011, p. 306). The best available information does not indicate that disease is a threat to this species; therefore, we conclude that disease is not a current threat the Pacific sheath-tailed bat or likely to become a threat in the future
owever, disease has not been observed either in the Mariana or South Pacific subspecies of Pacific sheath-tailed bat (Palmeirim et al. 2007, p. 517; Wiles et al. 2011, p. 306). The best available information does not indicate that disease is a threat to this species; therefore, we conclude that disease is not a current threat the Pacific sheath-tailed bat or likely to become a threat in the future.
Conservation Efforts To Reduce Disease or Predation
We are unaware of any conservation actions planned or implemented at this time to abate the threats of predation by feral cats or rats to the Pacific sheath-tailed bat.
Summary of Factor C
In summary, based on the best available scientific and commercial information, we consider predation by nonnative mammals to be an ongoing threat to the Pacific sheath-tailed bat that will continue into the future. We do not find that disease is a threat to the Pacific sheath-tailed bat, or that it is likely to become one in the future.
D. The Inadequacy of Existing Regulatory Mechanisms
The Act requires that the Secretary assess available regulatory mechanisms in order to determine whether existing regulatory mechanisms may be inadequate as designed to address
American Samoa
In American Samoa no existing Federal laws, treaties, or regulations specify protection of the Pacific sheath-tailed bat's foraging habitat from the threats of agriculture and development, protect its known roosting caves from disturbance, or address the threat of predation by nonnative mammals such as rats and feral cats. However, some existing Territorial laws and regulations have the potential to afford the species some protection but their implementation does not achieve that result. The DMWR is given statutory authority to “manage, protect, preserve, and perpetuate marine and wildlife resources” and to promulgate rules and regulations to this end (American Samoa Code Annotated (ASCA), title 24, chapter 3)
cats. However, some existing Territorial laws and regulations have the potential to afford the species some protection but their implementation does not achieve that result. The DMWR is given statutory authority to “manage, protect, preserve, and perpetuate marine and wildlife resources” and to promulgate rules and regulations to this end (American Samoa Code Annotated (ASCA), title 24, chapter 3). This agency conducts monitoring surveys, conservation activities, and community outreach and education about conservation concerns. However, to our knowledge, DMWR has not used this authority to undertake conservation efforts for the Pacific sheath-tailed bat such as habitat protection and control of nonnative predators (DMWR 2006, pp. 79-80).
The Territorial Endangered Species Act provides for appointment of a Commission with the authority to nominate species as either endangered or threatened (ASCA, title 24, chapter 7). Regulations adopted under the Coastal Management Act (ASCA § 24.0501 et seq. ) also prohibit the taking of threatened or endangered species listed as threatened or endangered by the American Samoa Government (ASG) (American Samoa Administrative Code (ASAC) § 26.0220.I.c). However, the ASG has not listed the bat as threatened or endangered so these regulatory mechanisms do not provide protection for this species.
Commercial hunting and exportation of the Pacific sheath-tailed bat is prohibited under ASCA, title 24, chapter 23, “Conservation of Flying Foxes),” which also authorizes and directs the ASG DMWR to monitor flying fox populations, protect roosting areas from disturbance, and conduct other activities to manage and protect the species. This law identifies the Pacific sheath-tailed bat as a “flying fox species” (ASCA § 24.2302), but it has not led to measures implemented to protect the Pacific sheath-tailed bat or its habitat from known threats
” which also authorizes and directs the ASG DMWR to monitor flying fox populations, protect roosting areas from disturbance, and conduct other activities to manage and protect the species. This law identifies the Pacific sheath-tailed bat as a “flying fox species” (ASCA § 24.2302), but it has not led to measures implemented to protect the Pacific sheath-tailed bat or its habitat from known threats. The sale and purchase of all native bats is prohibited, and the take, attempt to take, and hunting of all native bats are prohibited unless explicitly allowed during an officially proclaimed hunting season (ASAC § 24.1106); take is defined as harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, or collect or to attempt to engage in such conduct (ASAC § 24.1101 (f)). However, we do not consider hunting or other forms of utilization to be a threat to the Pacific sheath-tailed bat.
Under a 50-year lease agreement between local villages, the American Samoa Government, and the Federal Government, approximately 8,000 ac (3,240 ha) of forested habitat on the islands of Tutuila, Tau, and Ofu are protected and managed in the National Park of American Samoa (NPSA Lease Agreement 1993). There is the potential for development surrounding park in-holdings, but such forest clearing would be isolated and small in scale compared to the large tracts of forested areas protected.
Under ASCA, title 24, chapter 08 (Noxious Weeds), the Territorial DOA has the authority to ban, confiscate, and destroy species of plants harmful to the agricultural economy. This authority was expanded by executive regulation so that the governor can ban the use or importation of any plant (ASCA § 24.0801). A permit from the director of the DOA is likewise required before plants may be imported to American Samoa (ASAC § 24.0328). These regulations are promulgated without consultation with the DMWR (DMWR 2006, p. 80)
ecies of plants harmful to the agricultural economy. This authority was expanded by executive regulation so that the governor can ban the use or importation of any plant (ASCA § 24.0801). A permit from the director of the DOA is likewise required before plants may be imported to American Samoa (ASAC § 24.0328). These regulations are promulgated without consultation with the DMWR (DMWR 2006, p. 80). Although these regulations provide some protection against the introduction of nonnative plant species, some imports permitted by the DOA, or that escape detection, could prove harmful to native species and their habitats in American Samoa. These regulations do not require any measures to control invasive nonnative plants that already are established and proving harmful to native species and their habitats.
Similarly, under ASCA, title 24, chapter 06 (Quarantine), the director of DOA has the authority to promulgate agriculture quarantine restrictions concerning animals. Using this authority, the DOA has restricted the importation of insects, farm animals, and “domestic pets,” including exotic animals, to entry by permit only (See ASAC § 24.0305 et. seq. ). Yet these restrictions do not expressly extend to all non-domesticated animals, nor does the DMWR have any consultative role in restricting entry of animals (or plants) harmful to wildlife or native flora. Accordingly, existing statutes and regulations leave a great deal of discretion to the DOA, which may not block the entry of animals harmful to native species or their habitats (DMWR 2006, p. 80). These regulations do not require any measures to control nonnative animals, such as mammalian predators, that already are established and proving harmful to native species and their habitats.
The Territorial Coastal Management Act establishes a land use permit (LUP) system for development projects and a Project Notification Review System (PNRS) for multi-agency review and approval of LUP applications (ASAC § 26.0206)
ot require any measures to control nonnative animals, such as mammalian predators, that already are established and proving harmful to native species and their habitats.
The Territorial Coastal Management Act establishes a land use permit (LUP) system for development projects and a Project Notification Review System (PNRS) for multi-agency review and approval of LUP applications (ASAC § 26.0206). The standards and criteria for review of LUP applications includes requirements to protect Special Management Areas (SMA), Unique Areas, and “critical habitats” where “sustaining the natural characteristics is important or essential to the productivity of plant and animal species, especially those that are threatened or endangered” on all lands and in coastal waters in the territory not under federal management authority (ASCA § 24.0501 et. seq. ). To date, three SMAs have been designated (Pago Pago Harbor, Leone Pala, and Nuuuli Pala; ASAC § 26.0221), and all are in coastal and mangrove habitats on the south shore of Tutuila that likely provide little foraging habitat and no roosting habitat for the Pacific sheath-tailed bat. The only Unique Area designated to date is the Ottoville Rainforest (American Samoa Coastal Management Program 2011, p. 52), also on Tutuila's south shore, which hypothetically may provide some foraging habitat for Pacific sheath-tailed bats, but it is a relatively small island of native forest in the middle of the heavily developed Tafuna Plain (Trail 1993, p. 4), far from the last known roost sites of this species. To the best of our knowledge, no critical habitats, as defined in the ASCA, have been designated. Nonetheless, these laws and regulations are designed to ensure that “environmental concerns et seq. )
ic sheath-tailed bats, but it is a relatively small island of native forest in the middle of the heavily developed Tafuna Plain (Trail 1993, p. 4), far from the last known roost sites of this species. To the best of our knowledge, no critical habitats, as defined in the ASCA, have been designated. Nonetheless, these laws and regulations are designed to ensure that “environmental concerns et seq. ). Because the implementation of these regulations has been minimal, and because review of permits is not rigorous and does not reliably include the members of the PNRS Board responsible for management of wildlife and natural resources (ASCA § 26.026.C), issuance of permits may not provide the habitat protection necessary for the conservation of the species and instead may result in loss of native habitat important to the Pacific sheath-tailed bat and other species as a result of land clearing for agriculture and development (DMWR 2006, p. 71). We conclude that the implementation of the Coastal Management Act and its PNRS is inadequate to address the threat of habitat destruction and degradation to the Pacific sheath-tailed bat.
In summary, some existing Territorial laws and regulatory mechanisms have the potential to offer some level of protection for the Pacific sheath-tailed bat and its habitat but are not currently implemented in a manner that would do so. The DMWR has not has not exercised its statutory authority to address threats to the bat such has nonnative species. The bat is not listed pursuant to the Territorial Endangered Species Act. The Coastal Management Act and its implementing regulations have the potential to address this threat more substantively, but are inadequately implemented. Therefore, we conclude that regulatory mechanisms in American Samoa do not address threats to the Pacific sheath-tailed bat
threats to the bat such has nonnative species. The bat is not listed pursuant to the Territorial Endangered Species Act. The Coastal Management Act and its implementing regulations have the potential to address this threat more substantively, but are inadequately implemented. Therefore, we conclude that regulatory mechanisms in American Samoa do not address threats to the Pacific sheath-tailed bat.
Samoa
In Samoa, the Animals Ordinance 1960 and the Protection of Wildlife Regulations 2004 regulate the protection, conservation, and utilization of terrestrial or land-dwelling species (MNRE and the Secretariat of the Pacific Regional Environment Programme (SPREP) 2012, p. 5). These laws and regulations prohibit, and establish penalties for committing, the following activities: (1) The take, keep, or kill of protected and partially protected animal species; (2) harm of flying species endemic to Samoa; and (3) the export of any bird from Samoa (MNRE and SPREP 2012, pp. 5-6). As described above, the Pacific sheath-tailed bat is neither endemic to the Samoan archipelago, nor is it listed as a “flying species endemic to Samoa” under the Protection of Wildlife Regulations 2004. Therefore, it is not protected by the current regulations.
The Planning and Urban Management Act 2004 (PUMA) and PUMA Environmental Impact Assessment (EIA) Regulation (2007) were enacted to ensure all development initiatives are properly evaluated for adverse environmental impacts (MNRE 2013, p. 93). The information required under PUMA for Sustainable Management Plans (Para. 18, Consultation) and Environmental Impact Assessments (Para. 46, Matters the Agency shall consider) does not include specific consideration for species or their habitat (PUMA 2004, as amended). Other similar approval frameworks mandated under other legislation address specific stressors and activities
(MNRE 2013, p. 93). The information required under PUMA for Sustainable Management Plans (Para. 18, Consultation) and Environmental Impact Assessments (Para. 46, Matters the Agency shall consider) does not include specific consideration for species or their habitat (PUMA 2004, as amended). Other similar approval frameworks mandated under other legislation address specific stressors and activities. These include the permit system under the Lands Surveys and Environment Act 1989 for sand mining and coastal reclamation, and ground water exploration and abstraction permits under the Water Resources Act 2008 (MNRE 2013, p. 93). The PUMA process has been gaining in acceptance and use; however, information is lacking on its effectiveness in preventing adverse impacts to species or their habitats (MNRE 2013, p. 93).
The Forestry Management Act 2011 aims to provide for the effective and sustainable management and utilization of forest resources. This law creates the requirement for a permit or license for commercial logging or harvesting of native, agro-forestry, or plantation forest resources (MNRE and SPREP 2012, p. 18). Permitted and licensed activities must follow approved Codes of Practice, forestry harvesting plans, and other requirements set by the Ministry of Natural Resources and Environment. Certain restrictions apply to actions on protected lands such as national parks and reserves. Permits or licenses may designate certain areas for the protection of the biodiversity, endangered species, implementation of international conventions, water resources, or area determined to be of significance on which no forestry activities may be undertaken (Forestry Management Act 2011, Para. 57). Although this law includes these general considerations for managing forest resources, it does not specifically provide protection to habitat for the Pacific sheath-tailed bat
iversity, endangered species, implementation of international conventions, water resources, or area determined to be of significance on which no forestry activities may be undertaken (Forestry Management Act 2011, Para. 57). Although this law includes these general considerations for managing forest resources, it does not specifically provide protection to habitat for the Pacific sheath-tailed bat.
Fiji
In Fiji, the Endangered and Protected Species Act (2002) regulates the international trade, domestic trade, possession, and transportation of species protected under CITES and other species identified as threatened or endangered under this act. Under the law, the Pacific sheath-tailed bat is recognized as an “indigenous species not listed under CITES.” Its recognition under the law can garner public recognition of the importance of conserving the bat and its habitat (Tuiwawa 2015, in litt.); however, because the focus of the legislation is the regulation of foreign and domestic trade, and the bat is not a species in trade, this law is not intended to provide protection for the bat or its habitat within Fiji. The best available information does not identify any laws or regulations protecting the habitat of the Pacific sheath-tailed bat in Fiji.
Tonga
In Tonga, the Birds and Fish Preservation (Amendment) Act 1989, is a law to “make provision for the preservation of wild birds and fish.” The law protects birds and fish, and provides for the establishment of protected areas, but it does not specifically protect the Pacific sheath-tailed bat or its habitat (Kingdom of Tonga 1988, 1989).
Vanuatu
In Vanuatu, the Environment Management and Conservation Act (2002) provides for conservation, sustainable development, and management of the environment of Vanuatu
f wild birds and fish.” The law protects birds and fish, and provides for the establishment of protected areas, but it does not specifically protect the Pacific sheath-tailed bat or its habitat (Kingdom of Tonga 1988, 1989).
Vanuatu
In Vanuatu, the Environment Management and Conservation Act (2002) provides for conservation, sustainable development, and management of the environment of Vanuatu. Areas of the law that may apply to species protection are the Environmental Impact Assessment process, which includes an assessment of protected, rare, threatened, or endangered species or their habitats in project areas, laws on bioprospecting, and the creation of Community Conservation Areas for the management of unique genetic, cultural, geological, or biological resources (Environmental Management and Conservation Act, Part 3, Environmental Impact Assessment). The Wild Bird Protection law (Republic of Vanuatu 2006) is limited to birds and does not offer protection to the Pacific sheath-tailed bat or its habitat.
Summary of Factor D
Based on the best available information, some existing regulatory mechanisms have the potential to offer protection, but their implementation does not reduce or remove threats to the Pacific sheath-tailed bat. In American Samoa the DMWR has not exercised its statutory authority to address threats to the bat such as predation by nonnative species, the bat is not listed pursuant to the Territorial Endangered Species Act, and the Coastal Management Act's land use permitting process is implemented inadequately to reduce or remove the threat of habitat destruction or
E. Other Natural or Manmade Factors Affecting Its Continued Existence
Roost Disturbance
Disturbance of roosting caves has contributed to the decline of the Pacific sheath-tailed bat throughout its range. Disturbance of roost caves by humans is likely to have occurred as a result of recreation, harvesting of co-occurring bat species, and, more commonly, guano mining (Grant et al. 1994, p. 135; Tarburton 2002, p
or Manmade Factors Affecting Its Continued Existence
Roost Disturbance
Disturbance of roosting caves has contributed to the decline of the Pacific sheath-tailed bat throughout its range. Disturbance of roost caves by humans is likely to have occurred as a result of recreation, harvesting of co-occurring bat species, and, more commonly, guano mining (Grant et al. 1994, p. 135; Tarburton 2002, p. 106; Wiles and Worthington 2002, p. 17; Palmeirim et al. 2005, pp. 63, 66; Malotaux 2012a in litt.; Malotaux 2012b in litt.). Roost disturbance is a well-known problem for many cave-dwelling species (Palmeirim et al. 2005, p. 3). Roosts are important sites for bats for mating, rearing young, and hibernating (in mid- and high-latitude species). Roosts often facilitate complex social interactions, offer protection from inclement weather, help bats conserve energy, and minimize some predation risk (Kunz and Lumsden 2003, p. 3); therefore, disturbance at caves and being repeatedly flushed from their roosts may cause bats to incur elevated energetic costs and other physiological stress and potentially increased risk of predation while in flight. Roost disturbance thus would negatively affect the survival and reproduction of the Pacific sheath-tailed bat.
In American Samoa, human disturbance at the two caves known to be historical roost sites for the bat is likely to be minimal. Guano mining occurred in the Anapeapea caves in the 1960s (Amerson et al. 1982, p. 74), but ceased due to the high salt content as a result of flooding with seawater during cyclones (Grant et al. 1994, p. 135). On Taveuni, Fiji, a cave known to be used as a roosting cave for the Pacific sheath-tailed bat is under more immediate threat by humans, as the cave is situated close to farmland, and is often used by locals (Malotaux 2012a, p. 3). On Upolu, Samoa, caves previously known to support bats are well-known and often visited by tourists; one within O le Pupu Pue National Park and others on village land (Tarburton 2011, pp. 40, 44)
wn to be used as a roosting cave for the Pacific sheath-tailed bat is under more immediate threat by humans, as the cave is situated close to farmland, and is often used by locals (Malotaux 2012a, p. 3). On Upolu, Samoa, caves previously known to support bats are well-known and often visited by tourists; one within O le Pupu Pue National Park and others on village land (Tarburton 2011, pp. 40, 44). Swiftlets ( Aerodramus spp.) are still observed in significant numbers in these caves (Tarburton 2011, p. 40), but these birds may be more tolerant than bats of human disturbance. We do not have information on human disturbance of roosts in Tonga or Vanuatu.
Goats are certain to enter caves for shelter from the sun and consequently can disturb roosting bats, although the extent of this disturbance is unknown (Scanlon 2015b, in litt.). Feral goats have been observed entering caves on Aguiguan Island for shelter, which disrupts colonies of the endangered swiftlet and is believed to disturb the Mariana subspecies of the Pacific sheath-tailed bat (Wiles and Worthington 2002, p. 17; Cruz et al. 2008, p. 243; Scanlon 2015b, in litt.). Researchers found that if caves that were otherwise suitable for bats were occupied by goats, there were no bats present in the caves (Guam Division of Aquatic and Wildlife Resources 1995, p. 95). On Yaqeta Island, Fiji, a cave once known to support several hundred Pacific sheath-tailed bats but now abandoned, is located within a small forest fragment frequented by goats (Scanlon et al. 2013, p. 453).
Populations of the Pacific sheath-tailed bat are concentrated in the caves where they roost, and chronic disturbance of these sites can result in the loss of populations, as described above. Because so few populations of this bat remain, loss of additional populations to roost disturbance further erodes its diminished abundance and distribution
frequented by goats (Scanlon et al. 2013, p. 453).
Populations of the Pacific sheath-tailed bat are concentrated in the caves where they roost, and chronic disturbance of these sites can result in the loss of populations, as described above. Because so few populations of this bat remain, loss of additional populations to roost disturbance further erodes its diminished abundance and distribution. Based on the above information, roost disturbance at caves accessible to humans and animals such as feral goats is a current threat and will likely continue to be a threat into the future.
Pesticides
The use of pesticides may negatively affect the Pacific sheath-tailed bat as a result of direct toxicity and a reduction in the availability of insect prey. Pesticides are known to adversely affect bat populations, either by secondary poisoning when bats consume contaminated insects or by reducing the availability of insect prey (Hutson et al., 2001, p. 138; Mickleburgh et al. 2002, p. 19). Pesticides may have contributed to declines and loss of the Mariana subspecies of Pacific sheath-tailed bat on islands where pesticides were once applied in great quantities (Guam, Saipan, and Tinian) (Wiles and Worthington 2002, p. 17).
In American Samoa and Samoa, current levels of pesticide use are likely lower than several decades ago when their use, particularly during the years in which taro was grown on large scales for export (1975-1985), coincided with the decline of bats in both places and has been implicated as the cause (Tarburton 2002, p. 107). However, Grant et al. (1994, pp. 135-136) dismissed the role of insecticides in the decline of the bat in American Samoa based on the absence of a similar population crash in the insectivorous white-rumped swiftlet ( Aerodramus spodiopygius ) and the limited use of agricultural and mosquito-control pesticides. On the island of Taveuni in Fiji, where bat populations have persisted at low levels over the last 10 years (Palmeirim et al. 2005, p
missed the role of insecticides in the decline of the bat in American Samoa based on the absence of a similar population crash in the insectivorous white-rumped swiftlet ( Aerodramus spodiopygius ) and the limited use of agricultural and mosquito-control pesticides. On the island of Taveuni in Fiji, where bat populations have persisted at low levels over the last 10 years (Palmeirim et al. 2005, p. 62, Malotaux 2012, in litt.), several locals reported that pesticide use was quite widespread, and their use may be similar on other Fijian islands (Malotaux 2012, in litt.). We do not have information about pesticide use in Tonga or Vanuatu. The best available information does not lead us to conclude that the use of pesticides is a current threat to the Pacific sheath-tailed bat or that it is likely to become one in the future.
Hurricanes
Although severe storms are a natural disturbance with which the Pacific sheath-tailed bat has coexisted for millennia, such storms exacerbate other threats to the species by adversely affecting habitat and food resources and pose a particular threat to its small and isolated remaining populations. American Samoa, Samoa, Fiji, Tonga, and Vanuatu are irregularly affected by hurricanes (Australian BOM and CSIRO 2011 Vol. 1, p. 41). Located in the Southern Hemisphere, these countries experience most hurricanes during the November to April wet season, with the maximum occurrence between January and March (Australian BOM and CSIRO 2011 Vol. 1, p. 47). In the 41-year period ending in 2010, more than 280 hurricanes passed within 250 mi (400 km) of Samoa (52 storms), Tonga (71), Fiji (70), and Vanuatu (94) (Australian BOM and CSIRO 2011, pp. 76, 186, 216, 244). In recent decades, several major (named) storms have hit American Samoa and Samoa (Tusi in 1987, Ofa in 1990, Val in 1991, Heta in 2004, and Olaf in 2005 (MNRE 2013, pp
2011 Vol. 1, p. 47). In the 41-year period ending in 2010, more than 280 hurricanes passed within 250 mi (400 km) of Samoa (52 storms), Tonga (71), Fiji (70), and Vanuatu (94) (Australian BOM and CSIRO 2011, pp. 76, 186, 216, 244). In recent decades, several major (named) storms have hit American Samoa and Samoa (Tusi in 1987, Ofa in 1990, Val in 1991, Heta in 2004, and Olaf in 2005 (MNRE 2013, pp. 31-32; Federal Emergency Management Agency 2015, in litt.)); Tonga (Waka in 2001 and Ian in 2014 (Tonga Meteorological Service 2006, in litt.; World Bank 2014, in litt.)); Fiji (Tomas in 2010 (Digital Journal 2010, in litt.)); and, most recently, Vanuatu (Pam in 2015 (BBC 2015, in litt.)).
The high winds, waves, strong storm surges, high rainfall, and flooding associated with hurricanes, particularly severe hurricanes (with sustained winds of at least 150 mi per hour or 65 m per second) cause direct mortality of the Pacific sheath-tailed bat. Cyclones Ofa (1990) and Val (1991) removed the dense vegetation that had obscured the et al. 1993, p. 52; Grant et al. 1994, p. 135). The majority of sheath-tailed bats in the cave likely were killed when the hurricane hit (Grant et al. 1994, p. 135).
Hurricanes also cause direct mortality of the Pacific sheath-tailed bat as a result of the bats' inability to forage during extended periods of high wind or rain, during which they may starve. Cyclone Val (December 1991) remained stationary over the Samoan archipelago for four days, and Pacific sheath-tailed bats likely were unable to feed during this time (Grant et al. 1994, p. 135). Despite the ability of Pacific sheath-tailed bats to enter torpor to survive episodes of inclement weather, the high ambient temperatures in Samoa may preclude the energy savings necessary to sustain a small (4-7-g) torpid bat for an extended period (Grant et al. 1994, p. 135)
ago for four days, and Pacific sheath-tailed bats likely were unable to feed during this time (Grant et al. 1994, p. 135). Despite the ability of Pacific sheath-tailed bats to enter torpor to survive episodes of inclement weather, the high ambient temperatures in Samoa may preclude the energy savings necessary to sustain a small (4-7-g) torpid bat for an extended period (Grant et al. 1994, p. 135).
Hurricanes may also cause modification of the roosting habitat of the Pacific sheath-tailed bat by modifying vegetation in and around cave entrances and altering climate conditions within roosting caves as a result. Microchiropterans, such as the Pacific sheath-tailed bat, can spend over half their lives in their roosts; consequently, the microclimate of these habitats can exert a strong influence over their heat-energy balance (Campbell et al. 2011, p. 174). The presence of nearby forest cover and a well-developed tree canopy at cave entrances is likely to be important in maintaining temperature and relative humidity, and minimizing air movement in bat roosts, while allowing for passage. O'Shea and Valdez (2009, pp. 77-78) characterized the limestone cave ecosystem of the Mariana subspecies on Aguiguan as having constant temperature, high relative humidity, and no major air movement. Although such data are lacking for the Pacific sheath-tailed bat, alteration of climate conditions has been implicated in the abandonment of roost caves by other bat species (Hutson et al. 2001, p. 101).
Loss of forest cover and associated insect prey for bats as a result of hurricanes can reduce foraging opportunities. Following Cyclones Ofa (1990) and Val (1991), about 90 percent of the forests on Upolu and Savaii were blown over or defoliated (Park et al. 1992, p. 4; Elmqvist et al. 2002, pp. 385, 388). Tarburton (2002, p. 107) noted that the abundance of flying insects remained low for weeks after cyclones had defoliated trees
d insect prey for bats as a result of hurricanes can reduce foraging opportunities. Following Cyclones Ofa (1990) and Val (1991), about 90 percent of the forests on Upolu and Savaii were blown over or defoliated (Park et al. 1992, p. 4; Elmqvist et al. 2002, pp. 385, 388). Tarburton (2002, p. 107) noted that the abundance of flying insects remained low for weeks after cyclones had defoliated trees. Although the Pacific sheath-tailed bat has the capacity to forage in a variety of habitats, a study of habitat use by the Mariana subspecies showed a clear preference for forested habitats (Esselstyn et al. 2004, p. 307). Finally, the Pacific sheath-tailed bat's severely diminished abundance and distribution increase the likelihood that mortality events will cause population-level impacts and increase the vulnerability of populations and of the species to environmental catastrophes. Based on the information described above, we consider hurricanes to be a factor that exacerbates other threats to the Pacific sheath-tailed bat.
Low Numbers of Individuals and Populations
The low numbers of individuals and populations of this subspecies place the Pacific sheath-tailed bat at great risk of extinction from inbreeding and stochastic events such as storms. The threat is significant for cave-dwelling species whose populations are often highly localized with few numbers of animals that can easily be lost in a severe storm, disease outbreak, or disturbance to the roost caves (Wiles and Worthington 2002, p. 20).
Species that undergo significant habitat loss and degradation and face other threats resulting in decline in numbers and range reduction are inherently highly vulnerable to extinction resulting from localized catastrophes such as severe storms or disease outbreaks, climate change effects, and demographic stochasticity (Shaffer 1981, p. 131; Gilpin and Soulé 1986, pp. 24-34; Pimm et al. 1988, p. 757; Mangel and Tier 1994, p. 607)
habitat loss and degradation and face other threats resulting in decline in numbers and range reduction are inherently highly vulnerable to extinction resulting from localized catastrophes such as severe storms or disease outbreaks, climate change effects, and demographic stochasticity (Shaffer 1981, p. 131; Gilpin and Soulé 1986, pp. 24-34; Pimm et al. 1988, p. 757; Mangel and Tier 1994, p. 607). Conditions leading to this level of vulnerability are easily reached by island species that face numerous threats such as those described above. Small populations persisting in fragmented habitat face increased risk from environmental catastrophes, such as hurricanes, which could immediately extinguish some or all of the remaining populations; demographic stochasticity that could leave the species without sufficient males or females to be viable; or inbreeding depression or loss of adaptive potential that can be associated with loss of genetic diversity and result in eventual extinction (Shaffer 1981, p. 131; Lacy 2000, pp. 40, 44-46). The problems associated with small population size and vulnerability to natural catastrophes or random demographic or genetic fluctuations are further magnified by synergistic interactions with ongoing threats such as those discussed above under Factors A and C (Lacy 2000, pp. 45-47).
Breakdown of the Metapopulation Equilibrium
The Pacific sheath-tailed bat is thought to have a metapopulation structure (Palmeirim et al. 2005, p. 29), and will only persist in an archipelago if the island colonization rate is sufficiently high to compensate for the rate of extirpation caused by stochastic factors on individual islands (Palmeirim et al. 2005, p. 36). However, the colonization rate is obviously proportional to the availability of source populations; immigration of bats to recolonize sites or islands where the species was extirpated is dependent on sufficient numbers of animals existing in multiple other sites or islands within dispersal distance (Hanski and Gilpin 1991, pp. 4-14)
tic factors on individual islands (Palmeirim et al. 2005, p. 36). However, the colonization rate is obviously proportional to the availability of source populations; immigration of bats to recolonize sites or islands where the species was extirpated is dependent on sufficient numbers of animals existing in multiple other sites or islands within dispersal distance (Hanski and Gilpin 1991, pp. 4-14). Consequently, the extirpation of the Pacific sheath-tailed bat from some islands, particularly from the largest islands, may in the long term result in the permanent regional extinction of the species, even if suitable environmental conditions persist on some islands (Palmeirim et al. 2005, p. 36). For example, the continued decline of the only significant source population of Pacific sheath-tailed bat in the Fijian archipelago greatly diminishes the probability of recolonization and persistence throughout the remainder of its range in Fiji, where it is currently considered to be extirpated or nearly extirpated. The loss of a functioning metapopulation is a current threat and will continue to be a threat in the future.
Climate Change
Our analyses under the Act include consideration of ongoing and projected changes in climate. The terms “climate” and “climate change” are defined by the Intergovernmental Panel on Climate Change (IPCC). “Climate” refers to the mean and variability of different types of weather conditions over time, with 30 years being a typical period for such measurements, although shorter or longer periods also may be used (IPCC 2013, p. 1,450). The term “climate change” thus refers to a change in the mean or variability of one or more measures of climate ( e.g., temperature or precipitation) that persists for an extended period, typically decades or longer, whether the change is due to natural variability, human activity, or both (IPCC 2013, p. 1,450). Various types of changes in climate can have direct or indirect effects on species
0). The term “climate change” thus refers to a change in the mean or variability of one or more measures of climate ( e.g., temperature or precipitation) that persists for an extended period, typically decades or longer, whether the change is due to natural variability, human activity, or both (IPCC 2013, p. 1,450). Various types of changes in climate can have direct or indirect effects on species. These effects may be positive, neutral, or negative and they may change over time, depending on the species and other relevant considerations, such as the effects of interactions of climate e.g., habitat fragmentation) (IPCC 2007, pp. 8-14, 18). Climate change will be a particular challenge for the conservation of biodiversity because the introduction and interaction of additional stressors may push species beyond their ability to survive (Lovejoy 2005, pp. 325-326). The synergistic effects of climate change and habitat fragmentation are the most menacing facet of climate change for biodiversity (Hannah et al. 2005, p. 4). Currently, there are no climate change studies that address impacts to the specific habitat of the Pacific sheath-tailed bat. There are, however, climate change studies that address potential changes in the tropical Pacific on a broader scale.
In our analyses, we reference the scientific assessment and climate change predictions for the western Pacific region prepared by the Pacific Climate Change Science Program (PCCSP), a collaborative research partnership between the Australian Government and 14 Pacific Island countries, including Samoa, Tonga, Fiji, and Vanuatu (Australian BOM and CSIRO 2011 Vol. 1, p. 15). The assessment builds on the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), and presents regional predictions for the area roughly between 25° S. to 20° N. and 120° E. to 150° W. (excluding the Australian region south of 10° S. and west of 155° E.) (Australian BOM and CSIRO 2011 Vol. 1, pp. 14, 20). The findings for Samoa (13° S
BOM and CSIRO 2011 Vol. 1, p. 15). The assessment builds on the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), and presents regional predictions for the area roughly between 25° S. to 20° N. and 120° E. to 150° W. (excluding the Australian region south of 10° S. and west of 155° E.) (Australian BOM and CSIRO 2011 Vol. 1, pp. 14, 20). The findings for Samoa (13° S. and 171° E.) may be used as a proxy for American Samoa (14° S. and 170° W.).
The annual average air temperatures and sea surface temperatures are projected to increase in American Samoa, Samoa, Fiji, Tonga, and Vanuatu, as well as throughout the western Pacific region (Australian BOM and CSIRO 2011 Vol. 2, pp. 91, 198, 228, 258). The projected regional warming is around 0.5-1.0 °C by 2030, regardless of the emissions scenario. By 2055, the warming is generally 1.0-1.5 °C with regional differences depending on the emissions scenario. Projected changes associated with increases in temperature include, but are not limited to, changes in mean precipitation with unpredictable effects on local environments (including ecosystem processes such as nutrient cycling), increased occurrence of drought cycles, increases in the intensity and number of severe storms, sea-level rise, a shift in vegetation zones upslope, and shifts in in the ranges and lifecycles of individual species (Loope and Giambelluca 1998, pp. 514-515; Pounds et al. 1999, pp. 611-612; IPCC AR4 2007, p. 48; Emanuel et al. 2008, p. 365; U.S. Global Change Research Program (US-GCRP) 2009, pp. 145-149, 153; Keener et al. 2010, pp. 25-28; Sturrock et al. 2011, p. 144; Townsend et al. 2011, pp. 14-15; Warren 2011, pp. 221-226; Finucane et al. 2012, pp. 23-26; Keener et al. 2012, pp. 47-51).
In the western Pacific region, increased ambient temperatures is projected to lead to increases in annual mean rainfall, the number of heavy rain days (20-50 mm), and extreme rainfall events in American Samoa, Samoa Fiji, Tonga, and Vanuatu (Australian BOM and CSIRO 2011 Vol
ownsend et al. 2011, pp. 14-15; Warren 2011, pp. 221-226; Finucane et al. 2012, pp. 23-26; Keener et al. 2012, pp. 47-51).
In the western Pacific region, increased ambient temperatures is projected to lead to increases in annual mean rainfall, the number of heavy rain days (20-50 mm), and extreme rainfall events in American Samoa, Samoa Fiji, Tonga, and Vanuatu (Australian BOM and CSIRO 2011 Vol. 1, p. 178; Australian BOM and CSIRO 2011 Vol. 2, pp. 87-88, 194-195, 224-225, 254-255). Impacts of increased precipitation on the Pacific sheath-tailed bat are unknown.
Hurricanes are projected to decrease in frequency in this part of the Pacific but increase in severity as a result of global warming (Australian BOM and CSIRO 2011 Vol. 2, pp. 88, 195, 225, 255). The high winds, waves, strong storm surges, high rainfall, and flooding associated with hurricanes, particularly severe hurricanes (with sustained winds of 150 mi (240 km) per hour), have periodically caused great damage to roosting habitat of Pacific sheath-tailed bats and to native forests that provide their foraging habitat (Craig et al. 1993, p. 52; Grant et al. 1994, p. 135; Tarburton 2002, pp. 105-108; Palmeirim et al. 2005, p. 35), as described in the “Hurricanes” section, above.
In the western Pacific region, sea level is projected to rise 1.18 to 6.3 in (30 to 160 mm) by 2030, 2.6 to 12.2 in (70 to 310 mm) by 2055, and 8.3 in to 2 ft (210 to 620 mm) by 2090 under the high-emissions scenario (Australian BOM and CSIRO 2011 Vol. 2, pp. 91, 198, 228, 258). The Pacific sheath-tailed bat is known to roost in areas close to the coast and forage in the adjacent forested areas at or near sea-level, as well as inland and at elevations up to 2,500 ft (762 m). The impacts of projected sea-level rise on low-elevation and coastal roosting and foraging habitat are likely to reduce and fragment the bat's habitat on individual high islands
p. 91, 198, 228, 258). The Pacific sheath-tailed bat is known to roost in areas close to the coast and forage in the adjacent forested areas at or near sea-level, as well as inland and at elevations up to 2,500 ft (762 m). The impacts of projected sea-level rise on low-elevation and coastal roosting and foraging habitat are likely to reduce and fragment the bat's habitat on individual high islands.
In summary, although we lack information about the specific effects of projected climate change on the Pacific sheath-tailed bat, we anticipate that increased ambient temperature, precipitation, hurricane intensity, and sea-level rise and inundation would create additional stresses on the bat and on its roosting and foraging habitat because it is vulnerable to these disturbances. The risk of extinction as a result of the effects of climate change increases when a species' range and habitat requirements are restricted, its habitat decreases, and its numbers and number of populations decline (IPCC 2007, pp. 8-11). In addition, the fragmented range, diminished number of populations, and low total number of individuals have caused the Pacific sheath-tailed bat to lose redundancy and resilience rangewide. Therefore, we would expect the Pacific sheath-tailed bat to be particularly vulnerable to the habitat impacts of projected environmental effects of climate change (Loope and Giambelluca 1998, pp. 504-505; Pounds et al. 1999, pp. 611-612; Still et al. 1999, p. 610; Benning et al. 2002, pp. 14,246-14,248; Giambelluca and Luke 2007, pp. 13-15). Based on the above information, we conclude that habitat impacts resulting from the effects of climate change are not a current threat but are likely to become a threat to the Pacific sheath-tailed bat in the future
nge (Loope and Giambelluca 1998, pp. 504-505; Pounds et al. 1999, pp. 611-612; Still et al. 1999, p. 610; Benning et al. 2002, pp. 14,246-14,248; Giambelluca and Luke 2007, pp. 13-15). Based on the above information, we conclude that habitat impacts resulting from the effects of climate change are not a current threat but are likely to become a threat to the Pacific sheath-tailed bat in the future.
Conservation Efforts To Reduce Other Natural or Manmade Factors Affecting Its Continued Existence
We are unaware of any conservation actions planned or implemented at this time to abate the threats of roost disturbance, low numbers, hurricanes, or breakdown of the metapopulation equilibrium that negatively impact the Pacific sheath-tailed bat.
Summary of Factor E
In summary, based on the best scientific and commercial information available, we consider other natural and manmade factors to be current and ongoing threats to the Pacific sheath-tailed bat. Roost disturbance, small population size, and breakdown of the metapopulation dynamic are threats to the Pacific sheath-tailed bat and are likely to continue in the future. The bat's small and isolated remaining populations are vulnerable to natural environmental catastrophes such as hurricanes, and the threats of small population size and hurricanes are likely to continue into the future. Due to reduced levels of pesticide use and the uncertainty regarding impacts to this species, we do not consider the use of pesticides to be a threat to the Pacific sheath-tailed bat. Although we do not consider climate change to be a current threat to the Pacific sheath-tailed bat, we anticipate that climate change is likely to exacerbate other threats to the species and to become a threat in the future
reduced levels of pesticide use and the uncertainty regarding impacts to this species, we do not consider the use of pesticides to be a threat to the Pacific sheath-tailed bat. Although we do not consider climate change to be a current threat to the Pacific sheath-tailed bat, we anticipate that climate change is likely to exacerbate other threats to the species and to become a threat in the future.
Synergistic Effects
In our analysis of the five factors, we found that the Pacific sheath-tailed bat is likely to be affected by loss of forest e.g., disease, pesticides, climate change) that we do not currently consider to be significantly affecting the Pacific sheath-tailed bat because of their low occurrence today or apparently minimal overall impact on the species. Multiple stressors acting in combination have greater potential to affect the Pacific sheath-tailed bat than each factor alone. The combined effects of environmental, demographic, and catastrophic-event stressors, especially on a small population can lead to a decline that is unrecoverable and results in extinction (Brook et al. 2008, pp. 457-458). The impacts of the stressors described above, which might be sustained by a larger, more resilient population, have the potential in combination to rapidly affect the size, growth rate, and genetic integrity of a species that persists as small, disjunct populations. Thus, factors that, by themselves, may not have a significant effect on the Pacific sheath-tailed bat, may affect the subspecies when considered in combination.
Proposed Determination for the Pacific Sheath-Tailed Bat
Section 4 of the Act (16 U.S.C. 1533), and its implementing regulations at 50 CFR part 424, set forth the procedures for adding species to the Federal Lists of Endangered and Threatened Wildlife and Plants
selves, may not have a significant effect on the Pacific sheath-tailed bat, may affect the subspecies when considered in combination.
Proposed Determination for the Pacific Sheath-Tailed Bat
Section 4 of the Act (16 U.S.C. 1533), and its implementing regulations at 50 CFR part 424, set forth the procedures for adding species to the Federal Lists of Endangered and Threatened Wildlife and Plants. Under section 4(a)(1) of the Act, we may list a species based on (A) The present or threatened destruction, modification, or curtailment of its habitat or range; (B) Overutilization for commercial, recreational, scientific, or educational purposes; (C) Disease or predation; (D) The inadequacy of existing regulatory mechanisms; or (E) Other natural or manmade factors affecting its continued existence. Listing actions may be warranted based on any of the above threat factors, singly or in combination.
We have carefully assessed the best scientific and commercial information available regarding the past, present, and future threats to the Pacific sheath-tailed bat. We find that the Pacific sheath-tailed bat is presently in danger of extinction throughout its entire range based on the severity and immediacy of the ongoing and projected threats described above. Habitat loss and degradation due to deforestation, predation by nonnative mammals, human disturbance of roost caves, and stochastic events such as hurricanes, floods, or disease outbreaks, which all pose a particular threat to the small and isolated remaining populations and probable low total abundance throughout its range, render the Pacific sheath-tailed bat in its entirety highly susceptible to extinction as a consequence of these imminent threats. The vulnerability of the species and its cave habitat to the impacts of predation and human disturbance is exacerbated by hurricanes and likely to be further exacerbated in the future by the effects of climate change, such as sea level rise, extreme rain events, and increased storm severity
eath-tailed bat in its entirety highly susceptible to extinction as a consequence of these imminent threats. The vulnerability of the species and its cave habitat to the impacts of predation and human disturbance is exacerbated by hurricanes and likely to be further exacerbated in the future by the effects of climate change, such as sea level rise, extreme rain events, and increased storm severity. The breakdown of the Pacific sheath-tailed bat's metapopulation structure is expected to reduce opportunities for repopulation following local extirpations of dwindling populations due to stochastic events. In addition, the continued decline of the last relatively large population of this species in Fiji further diminishes the probability of persistence throughout the remainder of its range where it is currently considered to be extirpated or nearly extirpated. In addition, the continued decline of the last relatively large population of this species in Fiji further diminishes the probability of persistence throughout the remainder of its range where it is currently considered to be extirpated or nearly extirpated.
In summary, habitat destruction and modification from deforestation is a threat to the Pacific sheath-tailed bat that is occurring throughout its range (Factor A). The threat of predation by nonnative predators such as rats and feral cats is ongoing (Factor C). Existing regulatory mechanisms do not address the threats to the Pacific sheath-tailed bat (Factor D). Human disturbance of roost caves, low numbers of individuals and populations and their concomitant vulnerability to catastrophic events such as hurricanes, and the breakdown of the metapopulation structure all are current threats to the bat as well (Factor E). All of these factors pose threats to the Pacific sheath-tailed bat, whether we consider their effects individually or cumulatively, and all of these threats will continue in the future
of individuals and populations and their concomitant vulnerability to catastrophic events such as hurricanes, and the breakdown of the metapopulation structure all are current threats to the bat as well (Factor E). All of these factors pose threats to the Pacific sheath-tailed bat, whether we consider their effects individually or cumulatively, and all of these threats will continue in the future.
The Act defines an endangered species as any species that is “in danger of extinction throughout all or a significant portion of its range” and a threatened species as any species “that is likely to become endangered throughout all or a significant portion of its range within the foreseeable future.” We find that the Pacific sheath-tailed bat is presently in danger of extinction throughout its entire range based on the severity and immediacy of threats currently impacting the species. Therefore, On the basis of the best available scientific and commercial information, we propose listing Pacific sheath-tailed bat as endangered in accordance with sections 3(6) and 4(a)(1) of the Act.
Under the Act and our implementing regulations, a species may warrant listing if it is in danger of extinction or likely to become so throughout all or a significant portion of its range. Because we have determined that the Pacific sheath-tailed bat is endangered throughout all of its range, no portion of its range can be “significant” for purposes of the definitions of “endangered species” and “threatened species.” See the Final Policy on Interpretation of the Phrase “Significant Portion of Its Range” in the Endangered Species Act's Definitions of “Endangered Species” and “Threatened Species” (79 FR 37577, July 1, 2014).
Mao, Gymnomyza samoensis
The genus Gymnomyza refers to birds in the honeyeater family Meliphagidae, which are restricted to a few islands in the southwestern Pacific Ocean. The mao ( Gymnomyza samoensis ), also called maomao, is one of three honeyeater species in the genus (Mayr 1945, p. 100)
pecies Act's Definitions of “Endangered Species” and “Threatened Species” (79 FR 37577, July 1, 2014).
Mao, Gymnomyza samoensis
The genus Gymnomyza refers to birds in the honeyeater family Meliphagidae, which are restricted to a few islands in the southwestern Pacific Ocean. The mao ( Gymnomyza samoensis ), also called maomao, is one of three honeyeater species in the genus (Mayr 1945, p. 100). We have carefully reviewed the available taxonomic information (Watling 2001, p. 174; BirdLife International 2013; Gill and Donsker 2015; ITIS 2015a) and have concluded the species is a valid taxon.
The mao is a large (approximately 11 in (28 cm)), “very dark-looking honeyeater . . . uniformly olive-black with a brown suffusion, except for an olive stripe beneath the eye. The “slender, down-curved bill and feet are black” (Watling 2001, p. 174). Butler and Stirnemann (2013, p. 25) report that male mao have blue eyes and are larger, while females are smaller with brown eyes. Juveniles have a shorter bill than adults, and eye color changes 2 months post-fledging (Butler and Stirnemann 2013, p. 25). The mao is a very vocal species and makes a variety of loud distinctive calls with bouts of calling lasting up to a minute (Watling 2001, p. 174). Calls differ between sexes (Butler and Stirnemann 2013, p. 25).
The mao is endemic to the Samoan archipelago. The species was thought to be primarily restricted to mature, well-developed, moist, mossy forests at upper elevations (Watling 2001, p. 175; Engbring and Ramsey 1989, p. 68), but has recently been observed at elevations ranging from 932 to 5,075 ft (284 to 1,547 m) and in ecosystems including lowland rainforest, disturbed secondary forest, and montane rainforest (MNRE 2006, pp. 9-10). The birds use the mid- to upper-canopy levels of the forest and
Butler and Stirnemann (2013, p. 30) provide the following information about the mao's habitat use
nd Ramsey 1989, p. 68), but has recently been observed at elevations ranging from 932 to 5,075 ft (284 to 1,547 m) and in ecosystems including lowland rainforest, disturbed secondary forest, and montane rainforest (MNRE 2006, pp. 9-10). The birds use the mid- to upper-canopy levels of the forest and
Butler and Stirnemann (2013, p. 30) provide the following information about the mao's habitat use. The birds only occur in forested areas with a canopy layer, including modified habitat such as plantations where large trees also are present. They do not occur in logged areas with no large trees or canopy. Mao are primarily found in the high canopy layer, but also spend considerable time foraging on the trunks of trees and feeding on nectar sources near the ground (such as ginger (family Zingiberaceae)) and in low bushes (such as Heliconia spp.). The mao selects territories with high tree species diversity and with appropriate nectar sources and a large tree from which the male sings. Trees near a commonly used singing tree are selected for nesting. No particular tree species is used for nesting, but all nests are built more than 5 meters above the ground.
Butler and Stirnemann (2013, pp. 19-32) provide the following information about mao life history and breeding behavior. Based on a study of 15 nests, the mao nests once a year, between June and October, and produces one egg per clutch (Butler and Stirnemann 2013, pp. 19-32). The nest consists of young branches of various trees and contains little lining (Butler and Stirnemann 2013, p. 25). Incubation lasts 19 days, and chicks fledge 21-22 days after hatching. Juveniles are dependent on adults for approximately 8 to 10 weeks post-fledging. The female is almost exclusively responsible for incubation and feeding the chick, and both adults defend the nest. The mao will re-nest if the first nest fails, but not if the first nesting attempt produces a chick. Pairs are highly territorial with high site fidelity
ays, and chicks fledge 21-22 days after hatching. Juveniles are dependent on adults for approximately 8 to 10 weeks post-fledging. The female is almost exclusively responsible for incubation and feeding the chick, and both adults defend the nest. The mao will re-nest if the first nest fails, but not if the first nesting attempt produces a chick. Pairs are highly territorial with high site fidelity.
The mao's diet consists primarily of nectar, and also includes some invertebrates and fruit (MNRE 2006, p. 11). Nectar is an especially important food source during the breeding season, and the mao will defend nectar patches (Butler and Stirnemann 2013, p. 30). The mao eats invertebrates by probing dead material and moss, and by gleaning from emerging leaves (Butler and Stirnemann 2013, p. 30). Females forage for invertebrates under dead leaves on the forest floor to feed their fledglings (Butler and Stirnemann 2013, p. 30). Fledglings solicit food from the female by begging continually from the forest floor (Butler and Stirnemann 2013, p. 28).
The mao was once found throughout Savaii and Upolu (Samoa) likely in forests ranging from the coast to mountain tops (MNRE 2006, p. 2). It is endemic to the islands of Savaii and Upolu, Samoa, and Tutuila Island, American Samoa (Engbring and Ramsey 1989, p. 68; Watling 2001, p. 174). The mao was observed during an 1839 expedition on Tutuila (Amerson et al. 1982, p. 72), two male specimens were collected there in 1924, and an unconfirmed observation of the mao on Tutuila was reported in 1977 (Engbring and Ramsey 1989, p. 68; Watling 2001, p. 174).
The mao is currently found only on the islands of Savaii and Upolu in Samoa (Amerson et al. 1982, p. 72; Engbring and Ramsey 1989, p. 68; Watling 2001, p. 74; MNRE 2006, p. 2). In 1984, the mao was reported as common in undisturbed upland forests (foothill, montane, and cloud forests above 1,970 ft (600 m)) of Upolu and Savaii (Bellingham and Davis 1988, p. 124)
89, p. 68; Watling 2001, p. 174).
The mao is currently found only on the islands of Savaii and Upolu in Samoa (Amerson et al. 1982, p. 72; Engbring and Ramsey 1989, p. 68; Watling 2001, p. 74; MNRE 2006, p. 2). In 1984, the mao was reported as common in undisturbed upland forests (foothill, montane, and cloud forests above 1,970 ft (600 m)) of Upolu and Savaii (Bellingham and Davis 1988, p. 124). A decline in distribution was observed in the 1990s following a period in which several powerful hurricanes hit Samoa: Tusi (1987), Ofa (1990), and Val (1991) (Lovegrove 1992, p. 26; MNRE 2006, pp. 2, 4). Otherwise, no detailed surveys of the mao were conducted before 2005, and little information exists regarding changes in abundance and distribution (MNRE 2006, p. 2). Surveys conducted in 2005-2006 found mao at seven sites on Upolu and Savaii in upland forested habitat, yielded a rough estimate of 500 individuals and indicated that numbers are declining (MNRE 2006, p. 4; Tipamaa 2007, in litt., cited in Birdlife International 2012). The Rapid Biodiversity Assessment of Upland Savaii, Samoa conducted in 2012 detected small numbers of the mao at two sites on the island (Atherton and Jefferies 2012, p. 14), and it is possible that the species has particular habitat requirements that have become limited in Samoa (MNRE 2013, p. 12). Neither the 2012 surveys nor a study of the species' biology and movements (Butler and Stirnemann 2013) yielded an updated population estimate. However, researchers observed that the species is rarer than previously thought and recommended that comprehensive surveys be conducted to generate a new population estimate (Stirnemann 2015, in litt).
The mao is likely extirpated from Tutuila Island in American Samoa (Freifeld 1999, p. 1,208). Surveys conducted on Tutuila Island in 1982 and 1986 and from 1992 to 1996 did not detect the mao (Amerson et al. 1982, p. 72; Engbring and Ramsey 1989; p. 68; Freifeld 2015 in litt.)
nd recommended that comprehensive surveys be conducted to generate a new population estimate (Stirnemann 2015, in litt).
The mao is likely extirpated from Tutuila Island in American Samoa (Freifeld 1999, p. 1,208). Surveys conducted on Tutuila Island in 1982 and 1986 and from 1992 to 1996 did not detect the mao (Amerson et al. 1982, p. 72; Engbring and Ramsey 1989; p. 68; Freifeld 2015 in litt.). Given that the species is noisy and conspicuous, it is unlikely that a population on Tutuila was missed during the surveys (Engbring and Ramsey 1989; p. 68). More recent surveys conducted by DMWR in forested habitats likely to support mao failed to detect their presence, further indicating the likelihood that the species no longer occurs on Tutuila (MacDonald 2015 in litt.).
The mao is listed as Endangered in the 2014 IUCN Red List (Birdlife International 2012). Endangered is IUCN's second most severe category of extinction assessment, which equates to a very high risk of extinction in the wild. IUCN criteria include the rate of decline, population size, area of geographic distribution, and degree of population and distribution fragmentation; however, IUCN rankings do not confer any actual protection or management.
Summary of Factors Affecting the Mao
A. The Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range
Habitat Destruction and Modification by Deforestation
Several thousand years of subsistence agriculture and more recent commercial agriculture has resulted in the alteration and great reduction in area of forests at lower elevations in the Samoan archipelago (Whistler 1994, p. 40; Mueller-Dombois and Fosberg 1998, p. 361; Whistler 2002, pp. 130-131)
tion, or Curtailment of Its Habitat or Range
Habitat Destruction and Modification by Deforestation
Several thousand years of subsistence agriculture and more recent commercial agriculture has resulted in the alteration and great reduction in area of forests at lower elevations in the Samoan archipelago (Whistler 1994, p. 40; Mueller-Dombois and Fosberg 1998, p. 361; Whistler 2002, pp. 130-131). In American Samoa, forest clearing for agriculture has contributed to habitat loss and degradation of forests in the lowland areas on Tutuila, and has the potential to spread into higher elevations and previously undisturbed forest; however, owing to limits on the feasibility of land-clearing imposed by the island's extreme topography, large areas of mature native rainforest have persisted. Deforestation, therefore, is unlikely to have been a cause of the mao's extirpation on this island in American Samoa.
The loss of forested habitat in Samoa is a primary threat to the mao (MNRE 2006, p. 5). Between 1954 and 1990, the amount of forested area declined from 74 to 46 percent of total land area in Samoa (Food and Agricultural Organization (FAO) 2005 in litt.). Between 1978 and 1990, 20 percent of all forest losses in Samoa were attributable to logging, with 97 percent of the logging having occurred on Savaii (Government of Samoa 1998 in Whistler 2002, p. 132). Forested land area in Samoa continued to decline at a rate of
The clearing of land for commercial agriculture has been the leading cause of deforestation in Samoa—more so than plantations or logging (Whistler 2002, p. 131). The transition from subsistence agriculture to developing cash crops for export ( e.g., taro, bananas, cacao) coupled with rapid population growth and new technologies, led to increased forest clearing in Samoa (Paulson 1994, pp. 326-332; Whistler 2002, pp. 130-131)
mercial agriculture has been the leading cause of deforestation in Samoa—more so than plantations or logging (Whistler 2002, p. 131). The transition from subsistence agriculture to developing cash crops for export ( e.g., taro, bananas, cacao) coupled with rapid population growth and new technologies, led to increased forest clearing in Samoa (Paulson 1994, pp. 326-332; Whistler 2002, pp. 130-131). Today, only 360 ac (146 ha) of native lowland rainforests (below 2,000 ft or 600 m) remain on Savaii and Upolu as a result of logging, agricultural clearing, residential clearing (including relocation due to tsunami), and natural causes such as rising sea level and hurricanes (MNRE 2013, p. 47). On Upolu, direct or indirect human influence has caused extensive damage to native forest habitat above 2,000 ft (600 m) (MNRE 2013, p. 13). Although forested, almost all upland forests on Upolu are largely dominated by introduced species today (MNRE 2013, p. 12). Savaii still has extensive upland forests which are for the most part undisturbed and composed of native species (MNRE 2013, p. 40). However, forest clearance remains an ongoing threat to the mao (MNRE 2006, p. 5). Logging is slowing down because the most accessible forest has largely been removed, but is an ongoing problem on Savaii despite years of effort to phase it out (MNRE 2006, p. 5; Atherton and Jeffries 2012, p. 17). Shifting or slash-and-burn cultivation is an increasing concern in upland forest that provides important refuges for the mao because farmers use forestry roads from heavily logged lowland forests to gain access to formerly inaccessible land (MNRE 2006, p. 5). For example, there is much concern about potential forest loss because of road that has been bulldozed into the cloud forest (above 3,280 ft (1,000 m)) on Savaii, apparently illegally (Atherton and Jeffries 2012, p. 16)
t that provides important refuges for the mao because farmers use forestry roads from heavily logged lowland forests to gain access to formerly inaccessible land (MNRE 2006, p. 5). For example, there is much concern about potential forest loss because of road that has been bulldozed into the cloud forest (above 3,280 ft (1,000 m)) on Savaii, apparently illegally (Atherton and Jeffries 2012, p. 16). Such roads provide vectors for invasive nonnative plant and animal species as well, thus exacerbating those threats to the mao and its habitat (Atherton and Jeffries 2012, p. 108).
Habitat quality has also degraded with the loss of closed forest space (MNRE 2006, p. 5; Butler and Stirnemann 2013, p. 22). An analysis in 1999 identified 32 percent of the total forest cover as “open” forest (less than 40 percent tree cover) and less than 0.05 percent as “closed” forest, largely as a result of damage from Cyclones Ofa and Val (Butler and Stirnemann 2013, p. 22). An additional 24 percent of the forest cover is classified as secondary re-growth forest. As a result, the montane forest in Samoa is now extremely open and patchy with fewer food resources for birds, including the mao (Butler and Stirnemann 2013, p. 22). The montane forests are also increasingly vulnerable to invasion by nonnative trees and other plants (Butler and Stirnemann 2013, p. 22), which adversely affect native forests through competition for light, nutrients, and water; chemical inhibition; and prevention of reproduction. Loss of forest is likely to affect the mao by reducing breeding, nesting, and foraging habitat, increasing forest fragmentation, and increasing the abundance and diversity of invasive species (Butler and Stirnemann 2013, p. 22).
On the island of Tutuila, American Samoa, agriculture and urban development covers approximately 24 percent of the island, and up to 60 percent of the island contains slopes of less than 30 percent where additional land clearing is feasible (ASCC 2010, p. 13; DWMR 2006, p. 25)
orest fragmentation, and increasing the abundance and diversity of invasive species (Butler and Stirnemann 2013, p. 22).
On the island of Tutuila, American Samoa, agriculture and urban development covers approximately 24 percent of the island, and up to 60 percent of the island contains slopes of less than 30 percent where additional land clearing is feasible (ASCC 2010, p. 13; DWMR 2006, p. 25). Farmers are increasingly encroaching into some of the steep forested areas as a result of suitable flat lands already being occupied with urban development and agriculture (ASCC 2010, p. 13). Consequently, agricultural plots have spread from low elevations up to middle and some high elevations on Tutuila.
In summary, deforestation by land-clearing for agriculture has been the major contributing factor in the loss and degradation of forested habitat for the mao throughout its range in Samoa and American Samoa, and logging has been an additional major factor in loss and degradation of forest habitat in Samoa. The majority of the lowland forests have either been lost or fragmented by land-clearing for agriculture. Upland areas in Samoa have suffered extensive deforestation from logging and are increasingly at risk as agriculture and development expand into these areas. Based on the above information, we conclude that the threat of habitat destruction and modification by agriculture and development is a current threat to the mao and will continue into the future.
Habitat Destruction and Modification by Nonnative Plants
Nonnative plant species can degrade the habitat of native species and their impacts to native forest often are facilitated or exacerbated by the impacts of other threats such as hurricanes, agriculture and development, and feral ungulates.
The native flora of the Samoan archipelago (plant species that were present before humans arrived) consisted of approximately 550 taxa, 30 percent of which were endemic (species that occur only in the American Samoa and Samoa) (Whistler 2002, p. 8)
ive forest often are facilitated or exacerbated by the impacts of other threats such as hurricanes, agriculture and development, and feral ungulates.
The native flora of the Samoan archipelago (plant species that were present before humans arrived) consisted of approximately 550 taxa, 30 percent of which were endemic (species that occur only in the American Samoa and Samoa) (Whistler 2002, p. 8). An additional 250 plant species have been intentionally or accidentally introduced and have become naturalized with 20 or more of these considered invasive or potentially invasive in American Samoa (Whistler 2002, p. 8; Space and Flynn 2000, pp. 23-24). Of these approximately 20 or more nonnative pest plant species, at least 10 have altered or have the potential to alter the habitat of the mao and the other four species proposed for listing (Atkinson and Medeiros 2006, p. 18; Craig 2009, pp. 94, 97-98; ASCC 2010, p. 15).
Nonnative plants can degrade native habitat in Pacific island environments by: (1) Modifying the availability of light through alterations of the canopy structure; (2) altering soil-water regimes; (3) modifying nutrient cycling; (4) ultimately converting native-dominated plant communities to nonnative plant communities; and (5) increasing the frequency of landslides and erosion (Smith 1985, pp. 217-218; Cuddihy and Stone, 1990, p. 74; Matson 1990, p. 245; D'Antonio and Vitousek 1992, p. 73; Vitousek et al. 1997, pp. 6-9; Atkinson and Medeiros 2006, p. 16). Nonnative plant species often exploit the disturbance caused by other factors such as hurricanes, agriculture and development, and feral ungulates, and thus, in combination reinforce or exacerbate their negative impacts to native habitats
-218; Cuddihy and Stone, 1990, p. 74; Matson 1990, p. 245; D'Antonio and Vitousek 1992, p. 73; Vitousek et al. 1997, pp. 6-9; Atkinson and Medeiros 2006, p. 16). Nonnative plant species often exploit the disturbance caused by other factors such as hurricanes, agriculture and development, and feral ungulates, and thus, in combination reinforce or exacerbate their negative impacts to native habitats. Although the areas within the National Park of American Samoa (NPSA, on the islands of Tutuila, Ofu, and Tau) contain many areas that are relatively free of human disturbance and alien invasion and largely represent pre-contact vegetation, the threat of invasion and further spread by nonnative plant species poses immense cause for concern (Atkinson and Medeiros 2006, p. 17; ASCC 2010, p. 22).
The invasive vines Merremia peltata and Mikania micrantha have serious impacts in forested areas and prevent reforestation of former agriculture areas in Samoa and American Samoa; they are prolific invaders of forest gaps and disturbed sites, and can have a smothering effect on growing trees, blocking sunlight to sub-canopy and undergrowth vegetation (MNRE 2013, p. 29). Similarly, several invasive trees also negatively affect native forests in Samoa by outcompeting native species Falcataria moluccana (albizia, tamaligi), Castilla elastica (Mexican rubber tree, pulu mamoe), Spathodea campanulata (African tulip, faapasi), and Funtumia elastica (African rubber tree, pulu vao) (MNRE 2013, p. 29). In addition, the invasive shrub Clidemia hirta is found in remote areas of upland forests in Savaii (Atherton and Jeffries 2012, p. 103). Although the mao forage and occasionally nest in modified habitat such as plantation areas where nonnative trees that provide nectar and nesting habitat ( e.g., Falcataria moluccana ) may occur, these habitats lack the high tree-species diversity preferred by the mao and also place the species at a greater risk of predation by nonnative predators (see Factor C below) (Butler and Stirnemann 2013, p. 30)
ugh the mao forage and occasionally nest in modified habitat such as plantation areas where nonnative trees that provide nectar and nesting habitat ( e.g., Falcataria moluccana ) may occur, these habitats lack the high tree-species diversity preferred by the mao and also place the species at a greater risk of predation by nonnative predators (see Factor C below) (Butler and Stirnemann 2013, p. 30). In summary, while the best available information does not provide the exact distribution of nonnative plant species, the habitat-modifying impacts of nonnative species are expected to continue and are not likely to be reduced in the future. Based on the above information, we conclude that the threat of habitat destruction and modification by nonnative plant species is a current threat to the mao and will continue into the future.
The following list provides a brief description of the nonnative plants that have the greatest negative impacts to the native forest habitat for the mao in American Samoa (Space and Flynn 2000, pp. 23-24; Craig 2009, pp. 94, 96-98; ASCC 2010, p. 15):
Adenanthera pavonina (red bean tree, coral bean tree, lopa), native to India and Malaysia, is a medium-sized tree up to 50 ft (15 m) high that invades intact forests as well as disturbed sites, and can quickly form large stands (GISD 2006). In American Samoa, it is invasive in secondary forests, but also has the ability to become more widely established on Tutuila and the Manua Islands (Space and Flynn 2000, p. 4). It is considered to have negative impacts on the native forests in American Samoa because the trees produce large quantities of seed, grow on a variety of soils, and can overtop many native trees and eventually form monotypic stands (Space and Flynn 2002, p. 5).
Castilla elastica (Mexican rubber tree, pulu mamoe), native to tropical America, is a medium-sized tree 15 to 30 ft (5 to 10 m) high that can invade intact forest where it reproduces prolifically and can crowd out native species (NPSA 2012, in litt.)
uantities of seed, grow on a variety of soils, and can overtop many native trees and eventually form monotypic stands (Space and Flynn 2002, p. 5).
Castilla elastica (Mexican rubber tree, pulu mamoe), native to tropical America, is a medium-sized tree 15 to 30 ft (5 to 10 m) high that can invade intact forest where it reproduces prolifically and can crowd out native species (NPSA 2012, in litt.). It has displaced significant areas of lowland forest in Samoa, and is now considered to be an important threat to native forests in American Samoa (Atkinson and Medeiros 2006, p. 18).
Cinnamomum verum (cinnamon, tinamoni), native to south Asia, is a fast-growing, medium-sized tree up to 30 ft (9 m) high with aromatic bark and leaves. It forms dense root mats that inhibit establishment of other plants, and can shade out other tree species and thus create monotypic stands. On Tutuila, it is actively spreading in the ridge forests of Mt. Matafao, Matuu, and Maloata (Space and Flynn 2000, p. 4; NPSA 2012, in litt.).
The shrub Clidemia hirta (Koster's curse), native to the New World from Mexico to Argentina, grows to be 6.6 ft (2 m) in height, forms a dense understory, shades out native plants, and prevents their regeneration (Wagner et al. 1985, p. 41; Smith 1989, p. 64). On Tau, it has become a serious problem in the unique summit scrub community (Whistler 1992, p. 22).
Falcataria moluccana (albizia, tamaligi), native to Moluccas, New Guinea, New Britain, and the Solomon Islands, is a tree that can reach 131 ft (40 m) in height and has a wide-spreading canopy. It grows rapidly and outcompetes slow-growing native trees by reducing light availability, and its abundant, high-nutrient litter alters soil chemistry (GISD 2008). Its shallow root system may lead to soil instability and landslides (Atkinson and Medeiros 2006, p. 17).
Funtumia elastica (African rubber tree, pulu vao), is a medium-sized tree up to 100 ft (30 m) tall native to tropical Africa (U.S
t grows rapidly and outcompetes slow-growing native trees by reducing light availability, and its abundant, high-nutrient litter alters soil chemistry (GISD 2008). Its shallow root system may lead to soil instability and landslides (Atkinson and Medeiros 2006, p. 17).
Funtumia elastica (African rubber tree, pulu vao), is a medium-sized tree up to 100 ft (30 m) tall native to tropical Africa (U.S. Department of Agriculture—Agricultural Research Service (USDA) 2006). This tree is invasive because of its “parachute seeds” that can disperse long distances and germinate in sunny or shady conditions (Whistler 2002, p. 122). Funtumia has become a dominant subcanopy and understory tree in the western half of Upolu where it can form monotypic forests (Pearsall and Whistler 1991, p. 30). It is also established and becoming dominant on eastern Savaii (Whistler 2002, p. 122). This species has the potential to become a major problem in American Samoa due to its proximity and the volume of traffic with Samoa (Space and Flynn 2000, p. 12).
Leucaena leucocephala (wild tamarind, lusina, fua pepe), a shrub native to the neotropics, is a nitrogen-fixer and an aggressive competitor that often forms the dominant element of the vegetation (Geesink et al. 1999, pp. 679-680). It crowds out native species and resprouts vigorously after cutting, and seeds can remain viable for 10 to 20 years (Craig 2009, p. 98).
Merremia peltata (Merremia, fue lautetele), is an indigenous, sprawling, or high-climbing vine that can invade areas following disturbances such as land-clearing and hurricanes. This fast-growing vine can smother plantation and forest trees (Craig 2009, p. 98).
Mikania micrantha (mile-a-minute vine, fue saina), native to tropical America, is a scrambling or climbing herbaceous vine, that retards forest regeneration with its smothering growth (Whistler 1994, p. 42). This sun-loving, shade-intolerant vine is a major pest of plantations and forests on all major American Samoa islands (Space and Flynn 2000, p
lantation and forest trees (Craig 2009, p. 98).
Mikania micrantha (mile-a-minute vine, fue saina), native to tropical America, is a scrambling or climbing herbaceous vine, that retards forest regeneration with its smothering growth (Whistler 1994, p. 42). This sun-loving, shade-intolerant vine is a major pest of plantations and forests on all major American Samoa islands (Space and Flynn 2000, p. 5; Craig 2009, p. 94).
Psidium cattleianum (strawberry guava, kuava) is a tall shrub or small tree that forms dense stands in which few other plants can grow, displacing native vegetation through competition. The fruit is eaten by feral pigs and birds that disperse the seeds throughout the forest (Smith 1985, p. 200; Wagner et al. 1985, p. 24). It is thought to have been cultivated in American Samoa for more than 40 years and has become naturalized in lowland rainforest on western Tutuila.
Spathodea campanulata (African tulip, faapasi), native to tropical Africa, is a large tree up to 80 ft (24 m) or more in height with showy red-orange tulip-like flowers and pods containing hundreds of wind-dispersed seeds (Pacific Islands Ecosystems at Risk (PIER) 2013). It is particularly invasive in low- to mid-elevation forests, and can spread in open agricultural land, waste areas, and intact native forest, forming dense stands that shade out other vegetation (GISD 2010).
Habitat Destruction and Modification by Nonnative Ungulates
Feral pigs ( Sus scrofa ) cause multiple negative impacts to island ecosystems including the destruction of vegetation, spread of invasive nonnative plant species, and increased soil erosion. In addition, feral cattle ( Bos taurus ) consume tree seedlings and browse saplings, and combined with undergrowth disturbance, prevent forest regeneration, subsequently opening the forest to invasion by nonnative species (Cuddihy 1984, p. 16).
Feral pigs are known to cause deleterious impacts to ecosystem processes and functions throughout their worldwide distribution (Aplet et al. 1991, p
ion. In addition, feral cattle ( Bos taurus ) consume tree seedlings and browse saplings, and combined with undergrowth disturbance, prevent forest regeneration, subsequently opening the forest to invasion by nonnative species (Cuddihy 1984, p. 16).
Feral pigs are known to cause deleterious impacts to ecosystem processes and functions throughout their worldwide distribution (Aplet et al. 1991, p. 56; Anderson and Stone 1993, p. 201; Campbell and Long 2009, p. 2,319). Feral pigs are extremely destructive and have both direct and et al. 2009, p. 547). In addition, pig rooting and wallowing contributes to erosion by clearing vegetation and creating large areas of disturbed soil, especially on slopes (Smith 1985, pp. 190, 192, 196, 200, 204, 230-231; Stone 1985, pp. 254-255, 262-264; Tomich 1986, pp. 120-126; Cuddihy and Stone 1990, pp. 64-65; Aplet et al. 1991, p. 56; Loope et al. 1991, pp. 18-19; Gagne and Cuddihy 1999, p. 52; Nogueira-Filho et al. 2009, p. 3,681; CNMI-Statewide Assessment and Resource Strategy (SWARS) 2010, p. 15; Dunkell et al. 2011, pp. 175-177; Kessler 2011, pp. 320, 323). Erosion resulting from rooting and trampling by pigs impacts native plant communities by contributing to watershed degradation and alteration of plant nutrient status, and increasing the likelihood of landslides (Vitousek et al. 2009, pp. 3,074-3,086; Chan-Halbrendt et al. 2010, p. 251; Kessler 2011, pp. 320−324). In the Hawaiian Islands, pigs have been described as the most pervasive and disruptive nonnative influence on the unique native forests, and are widely recognized as one of the greatest current threats to Hawaii's forest ecosystems (Aplet et al. 1991, p. 56; Anderson and Stone 1993, p. 195).
In American Samoa, feral pigs continue to negatively affect forested habitats. Feral pigs have been present in American Samoa since antiquity (American Samoa Historic Preservation Office 2015, in litt.)
influence on the unique native forests, and are widely recognized as one of the greatest current threats to Hawaii's forest ecosystems (Aplet et al. 1991, p. 56; Anderson and Stone 1993, p. 195).
In American Samoa, feral pigs continue to negatively affect forested habitats. Feral pigs have been present in American Samoa since antiquity (American Samoa Historic Preservation Office 2015, in litt.). In the past, hunting pressure kept their numbers down, however, increasing urbanization and increasing availability of material goods has resulted in the decline in the practice of pig hunting to almost nothing (Whistler 1992, p. 21; 1994, p. 41). Feral pigs are moderately common to abundant in many forested areas, where they spread invasive plants, damage understory vegetation, and destroy riparian areas by their feeding and wallowing behavior (DMWR 2006, p. 23; ASCC 2010, p. 15). Feral pigs are a serious problem in the NPSA because of the damage they cause to native vegetation through their rooting and wallowing (Whistler 1992, p. 21; 1994, p. 41; Hoshide 1996, p. 2; Cowie and Cook 1999, p. 48; Togia pers. comm. in Loope et al. 2013, p. 321). Such damage to understory vegetation is likely to reduce foraging opportunities for the mao. Pig densities have been reduced in some areas by snaring and hunting, but remain high in other areas (ASCC 2010, p. 15).
In Samoa, feral pigs are present throughout lowland and upland areas on Savaii, and are considered to have a negative impact on the ecological integrity of upland forests of Savaii, an important conservation area for the mao and other rare species (Atherton and Jeffries 2012, p. 17). During recent surveys, feral pig activity was common at most sites in upland forests on Savaii, and was even detected at the upper range of the mao at an elevation of 4,921 ft (1,500 m) (Atherton and Jefferies 2012, pp. 103, 146)
ive impact on the ecological integrity of upland forests of Savaii, an important conservation area for the mao and other rare species (Atherton and Jeffries 2012, p. 17). During recent surveys, feral pig activity was common at most sites in upland forests on Savaii, and was even detected at the upper range of the mao at an elevation of 4,921 ft (1,500 m) (Atherton and Jefferies 2012, pp. 103, 146). Significant numbers of feral cattle were present in an upland site where their trampling had kept open grassy areas within forested flats, and where mao had previously been observed (Atherton and Jeffries 2012, pp. 103-105). Trampling in forested areas damages understory vegetation and is likely to reduce foraging opportunities for mao as well as provide vectors for invasion by nonnative plants. In summary, the widespread disturbance caused by feral ungulates is likely to continue to negatively impact the habitat of the mao. Based on the above information, we conclude that habitat destruction and modification by feral ungulates is a threat to the mao.
Conservation Efforts To Reduce Habitat Destruction, Modification, or Curtailment of Its Range
American Samoa
The National Park of American Samoa (NPSA) was established to preserve and protect the tropical forest and archaeological and cultural resources, to maintain the habitat of flying foxes, to preserve the ecological balance of the Samoan tropical forest, and, consistent with the preservation of these resources, to provide for the enjoyment of the unique resources of the Samoan tropical forest by visitors from around the world (Public Law 100-571, Public Law 100-336). Under a 50-year lease agreement between local villages, the American Samoa Government, and the Federal Government, approximately 8,000 ac (3,240 ha) of forested habitat on the islands of Tutuila, Tau, and Ofu are protected and managed (NPSA Lease Agreement 1993)
joyment of the unique resources of the Samoan tropical forest by visitors from around the world (Public Law 100-571, Public Law 100-336). Under a 50-year lease agreement between local villages, the American Samoa Government, and the Federal Government, approximately 8,000 ac (3,240 ha) of forested habitat on the islands of Tutuila, Tau, and Ofu are protected and managed (NPSA Lease Agreement 1993).
Several programs and partnerships to address the threat of nonnative plant species have been established and are ongoing in American Samoa. Since 2000, the NPSA has implemented an invasive plant management program that has focused on monitoring and removal of nonnative plant threats. The nonnative plant species prioritized for removal include the following: Adenanthera pavonina or lopa, Castilla elastica or pulu mamoe, Falcataria moluccana or tamaligi, Leucaena leucocephala or lusina, and Psidium cattleianum or strawberry guava (Togia 2015, in litt.). In particular, efforts have been focused on the removal of the tamiligi from within the boundaries of the NPSA as well as in adjacent areas (Hughes et al. 2012).
The thrip Liothrips urichi is an insect that was introduced to American Samoa in the 1970s as a biocontrol for the weed Clidemia hirta (Tauiliili and Vargo 1993, p. 59). This thrip has been successful at controlling Clidemia on Tutuila. Though Clidemia is still common and widespread throughout Tutuila, thrips inhibit its growth and vigor, preventing it from achieving ecological dominance (Cook 2001, p. 143).
In 2004, the American Samoa Invasive Species Team (ASIST) was established as an inter-agency team of nine local government and Federal agencies. The mission of ASIST is to reduce the rate of invasion and impact of invasive species in American Samoa with the goals of promoting education and awareness on invasive species and preventing, controlling, and eradicating invasive species. In 2010, the U.S
In 2004, the American Samoa Invasive Species Team (ASIST) was established as an inter-agency team of nine local government and Federal agencies. The mission of ASIST is to reduce the rate of invasion and impact of invasive species in American Samoa with the goals of promoting education and awareness on invasive species and preventing, controlling, and eradicating invasive species. In 2010, the U.S. Forest Service conducted an invasive plant management workshop for Territorial and Federal agencies, and local partners (Nagle 2010 in litt.). More recently, the NPSA produced a field guide of 15 invasive plants that the park and its partners target for early detection and response (NPSA 2012, in litt.).
In 1996, the NPSA initiated a feral pig control program that includes fencing and removal of pigs using snares in the Tutuila Island and Tau Island Units. Two fences have been constructed and several hundred pigs have been removed since 2007 (Togia 2015, in litt.). The program is ongoing and includes monitoring feral pig activity twice per year and additional removal actions as needed (Togia 2015, in litt.).
Samoa
In 2006, the Government of Samoa developed a recovery plan for the mao. The recovery plan identifies goals of securing the mao, maintaining its existing populations on Upolu and Savaii, and reestablishing populations at former sites (MNRE 2006). The plan has eight objectives: (1) Manage key forest areas on Upolu and Savaii where significant populations of the mao remain; (2) carry out detailed surveys to identify the numbers of pairs and establish monitoring; (3) increase understanding of the breeding and
The Mt. Vaea Ecological Restoration Project surveyed and mapped the presence of native bird and plant species and invasive plant species within lowland forest habitat of the 454-ac (183-ha) Mt. Vaea Scenic Reserve on Upolu, Samoa (Bonin 2008, pp. 2-5). The project was envisioned as the first demonstration project of invasive species management and forest restoration in Samoa
of the breeding and
The Mt. Vaea Ecological Restoration Project surveyed and mapped the presence of native bird and plant species and invasive plant species within lowland forest habitat of the 454-ac (183-ha) Mt. Vaea Scenic Reserve on Upolu, Samoa (Bonin 2008, pp. 2-5). The project was envisioned as the first demonstration project of invasive species management and forest restoration in Samoa. Phase I of the project resulted in the development of a restoration plan recommending removal of five priority invasive plant species and planting of native tree species (Bonin 2008, pp. viii, 24). Phase 2 of the project resulted in identifying techniques for treatment of two problematic rubber species ( Castilla elastica or pulu mamoe and Funtumia elastica or pulu vao) and replanting areas with native tree species (Bonin 2010, pp. 20-21).
The Two Samoas Environmental Collaboration Initiative brings together government agencies, nongovernmental organizations and institutions from American Samoa and Samoa and provides a platform for a single concerted effort to manage threats to environmental resources such as the management of fisheries, land-based sources of pollution, climate change, invasive species, and key or endangered species (MNRE 2014, p. 67). In 2010, a Memorandum of Understanding establishing the collaborative effort between the two countries was signed by the two agencies responsible for conservation of species and their habitats, MNRE (Samoa) and DMWR (American Samoa). This initiative establishes a framework for efforts to recover the mao in American Samoa and Samoa.
Summary of Factor A
In summary, based on the best available scientific and commercial information, we conclude that the destruction, modification, and curtailment of the mao's habitat and range are ongoing threats and these threats will continue into the future
(Samoa) and DMWR (American Samoa). This initiative establishes a framework for efforts to recover the mao in American Samoa and Samoa.
Summary of Factor A
In summary, based on the best available scientific and commercial information, we conclude that the destruction, modification, and curtailment of the mao's habitat and range are ongoing threats and these threats will continue into the future. The destruction and modification of habitat for the mao is caused by agriculture, logging, feral ungulates, and nonnative plant species, the impacts of all of which are exacerbated by hurricanes (see Factor E). The most serious threat identified has been the loss of forested habitat caused by forest clearing for agriculture, and logging. All of the above threats are ongoing and interact to exacerbate the negative impacts and increase the vulnerability of extinction of the mao.
B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes
In Samoa, there is anecdotal information suggesting that the mao has been shot by people who were afraid of their calls (MNRE 2006, p. 8). In addition, one individual reported that mao are eaten, or were eaten in the past, but it seems more likely these birds were shot accidentally by hunters who were targeting pigeons (MNRE 2006, p. 8). The mao has been protected under regulations enacted by the Government of Samoa in 1993 and revised in 2004 (MNRE 2006, p. 8). The best available information does not indicate overutilization for commercial, recreation, scientific, or educational purposes in American Samoa. Based on the above information, we conclude that hunting of the mao is unintentional or accidental; therefore, we do not consider the overutilization for commercial, recreational, scientific, or educational purposes to be a threat to the mao.
C. Disease or Predation
Predation
Nest predation by rats has negative impacts on many island birds, including the mao (Atkinson 1977, p. 129; 1985, pp. 55-70; Butler and Stirnemann 2013, p. 29; O'Donnell et al
f the mao is unintentional or accidental; therefore, we do not consider the overutilization for commercial, recreational, scientific, or educational purposes to be a threat to the mao.
C. Disease or Predation
Predation
Nest predation by rats has negative impacts on many island birds, including the mao (Atkinson 1977, p. 129; 1985, pp. 55-70; Butler and Stirnemann 2013, p. 29; O'Donnell et al. 2015, pp. 24-26). Rats have been identified as the main cause of decline in the closely related Gymnomyza aubryana in New Caledonia (MNRE 2006, p. 8). Juveniles spending time on the forest floor are also at risk from predation by feral cats (Butler and Stirnemann 2013, p. 31). Other potential predators include the native barn owl ( Tyto alba ) and wattled honeyeater ( Foulehaio carunculatus ); however, adults can potentially drive these species away from the nest (Butler and Stirnemann 2013, p. 31).
Butler and Stirnemann (2013, p. 29) captured footage of one nest depredation event by a black rat, which took a mao egg. The rat gained access to the egg by jumping on the incubating female's back from the branch above, driving the female off the nest. Combined with the disappearance of two females during the breeding season, this footage suggests that adult females are potentially vulnerable to predation on the nest at night, while they are incubating (Butler and Stirnemann 2013, p. 31), a phenomenon documented or suspected in other island bird species, which lack innate behavioral defenses against nonnative mammalian predators (see for example Robertson et al. 1994, p. 1,084; Armstrong et al. 2006, p. 1,034; VanderWerf 2009, p. 741). This potential bias toward predation of females has the potential to create a skewed sex ratio in mao populations (Robertson et al. pp. 1,083-1,084)
a phenomenon documented or suspected in other island bird species, which lack innate behavioral defenses against nonnative mammalian predators (see for example Robertson et al. 1994, p. 1,084; Armstrong et al. 2006, p. 1,034; VanderWerf 2009, p. 741). This potential bias toward predation of females has the potential to create a skewed sex ratio in mao populations (Robertson et al. pp. 1,083-1,084).
The location of mao nests affects their vulnerability to predation by rats; nests in close proximity to plantation habitats, where rats are most abundant, are particularly susceptible and experience low reproductive success (Butler and Stirnemann 2013, p. 31). Nests within 50 meters of a plantation are 40 percent more likely to be depredated than nests in forested areas farther from plantations (Butler and Stirnemann 2013, p. 31). Because good-quality, closed-canopy forest habitat remains in American Samoa, factors in addition to deforestation are likely responsible for the extirpation of the mao from American Samoa (MNRE 2006, p. 8), including predation by rats (Stirnemann 2015, in litt.). Habitat loss from clearing of native forest combined with an expansion of plantations in Samoa may lead to an increase in rat populations (which find ample food in plantation habitats) and a potential for an increase in the mao nest predation rate. In addition, the mao's low reproductive rate (one juvenile per year) and extended breeding season increase the likelihood of population-level effects of predation (Butler and Stirnemann 2013, p. 22).
Predation by feral cats has been directly responsible for the extinction of numerous birds on oceanic islands (Medina et al. 2011, p. 6). Native mammalian carnivores are absent from oceanic islands because of their low dispersal ability, but once introduced by humans, they become significant predators on native animals such as seabirds and landbirds that are not adapted to predation by terrestrial carnivores (Nogales et al. 2013, p. 804; Scott et al. 1986, p. 363; Ainley et al. 1997, p
on oceanic islands (Medina et al. 2011, p. 6). Native mammalian carnivores are a
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