Endangered and Threatened Wildlife and Plants; Mariana Fruit Bat (Pteropus mariannus mariannus, 1190-1210 [05-240]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 70, Number 4 (Thursday, January 6, 2005)]
[Rules and Regulations]
[Pages 1190-1210]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 05-240]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

RIN 1018-AH55


Endangered and Threatened Wildlife and Plants; Mariana Fruit Bat 
(Pteropus mariannus mariannus): Reclassification From Endangered to 
Threatened in the Territory of Guam and Listing as Threatened in the 
Commonwealth of the Northern Mariana Islands

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Final rule.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), reclassify 
from endangered to threatened status the Mariana fruit bat (Pteropus 
mariannus mariannus) from Guam,

[[Page 1191]]

under the authority of the Endangered Species Act of 1973, as amended 
(Act), and determine the Mariana fruit bat from the Commonwealth of the 
Northern Mariana Islands (CNMI) to be a threatened species under the 
authority of the Act. This rule lists the Mariana fruit bat as 
threatened throughout its range.
    The Mariana fruit bat was listed previously as endangered on Guam. 
The bat populations on the southern islands of the CNMI (Aguiguan, 
Tinian, and Saipan) were candidates for listing. The best available 
scientific information indicates that Mariana fruit bats on Guam and 
throughout the CNMI comprise one subspecies. The protections of the 
Act, therefore, apply to this subspecies throughout its known range in 
the Mariana archipelago.

DATES: This final rule is effective February 7, 2005.

ADDRESSES: Comments and materials received, as well as supporting 
documentation used in the preparation of this final rule, will be 
available for public inspection, by appointment, during normal business 
hours at the Pacific Islands Fish and Wildlife Office, U.S. Fish and 
Wildlife Service, 300 Ala Moana Boulevard, Room 3-122, Box 50088, 
Honolulu, HI 96850.

FOR FURTHER INFORMATION CONTACT: Gina Shultz, Assistant Field 
Supervisor, Pacific Islands Fish and Wildlife Office (see ADDRESSES 
section) (telephone 808/792-9400; facsimile 808/792-9581).

SUPPLEMENTARY INFORMATION:

Background

    The Mariana archipelago consists of the 15-island Commonwealth of 
the Northern Mariana Islands (CNMI) and the Territory of Guam, both 
within the jurisdiction of the United States. This archipelago extends 
470 miles (mi) (750 kilometers (km)) from 13[deg]14' N, 144[deg]45' W 
to 20[deg]3' N, 144[deg]54' W and is approximately 900 mi (1,500 km) 
east of the Philippine Islands (Figure 1). Nine of the 10 northern 
islands (Anatahan, Sarigan, Guguan, Alamagan, Pagan, Agrihan, Asuncion, 
Maug, and Uracas) are volcanic in origin, and Farallon de Medinilla and 
the five southern islands (Guam, Rota, Aguiguan, Tinian, and Saipan) 
are uplifted limestone plateaus with volcanic outcrops. Mariana fruit 
bats have historically inhabited all of these islands except Uracas, 
the northernmost island (Wiles and Glass 1990). Of the largest southern 
islands (Guam, Rota, Tinian, and Saipan), Guam supports the majority of 
the human population. The northern islands (north of Saipan) are either 
unoccupied or support only a few families. The climate is tropical, 
with daily mean temperatures of 75 to 90[deg] Fahrenheit (24 to 32[deg] 
Celsius), high humidity, and average annual rainfall of 80 to 100 
inches (in) (200 to 260 centimeters (cm)). Typhoons may strike the 
Mariana Islands during any month of the year, but are most frequent 
between July and October.
BILLING CODE 4310-55-P

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[GRAPHIC] [TIFF OMITTED] TR06JA05.002

BILLING CODE 4310-55-C

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Species Description and Biology

    The Mariana fruit bat is a medium-sized fruit bat in the family 
Pteropididae that weighs 0.66 to 1.15 pounds (330 to 577 grams) and has 
a forearm length ranging from 5.3 to 6.1 in (13.4 to 15.6 cm); males 
are slightly larger than females. The underside (abdomen) is colored 
black to brown, with gray hair interspersed, creating a grizzled 
appearance. The shoulders (mantle) and sides of the neck are usually 
bright golden brown, but may be paler in some individuals. The head 
varies from brown to dark brown. The well-formed and rounded ears and 
large eyes give the face a canine appearance; members of the family 
Pteropodidae often are referred to as flying foxes.
    The Mariana fruit bat is highly colonial, forming colonies of a few 
to over 800 animals (Wiles 1987a; Pierson and Rainey 1992; Worthington 
and Taisacan 1995). Bats group themselves into harems (1 male and 2 to 
15 females) or bachelor groups (predominantly males), or reside as 
single males on the edge of the colony (Wiles 1987a). On Guam, the 
average estimated sex ratio in a single colony varied from 37.5 to 72.7 
males per 100 females (Wiles 1982).
    Reproduction is believed to occur throughout the year in Pteropus 
mariannus yapensis on Yap (Falanruw 1988). Mating and the presence of 
nursing Pteropus mariannus mariannus young have been observed year-
round on Guam (Perez 1972; Wiles 1983) with no apparent peak in births 
(Wiles 1987a). Glass and Taisacan (1988) suggested a similar pattern on 
Rota, but also indicated that a peak birthing season may occur during 
May and June, as has been observed in other fruit bats (Pierson and 
Rainey 1992). Female bats of the family Pteropodidae have one offspring 
per year (Pierson and Rainey 1992), pups may be born in any month of 
the year. Observations on Guam between July 1982 and May 1985 found 262 
female bats, each with a single young (Service 1990). This reproductive 
rate, very low for a mammal of this size, results in a low maximum 
population growth rate, and thus a slow rate of recovery when a 
population is diminished (Pierson and Rainey 1992). Length of gestation 
and age of sexual maturity are unknown for the Mariana fruit bat; other 
related bats have a gestation period of approximately 4.6 to 6.3 months 
(Pierson and Rainey 1992). Age of sexual maturity is not known for the 
Mariana fruit bat, but Pteropus species typically do not breed before 
18 months of age (Pierson and Rainey 1992).

Taxonomy and Interisland Movements

    The fruit bats of the Mariana Islands consistently have been 
treated as one or more endemic subspecies or species; that is, they 
occur nowhere outside the archipelago (Andersen 1912; Kuroda 1938; 
Corbet and Hill 1980, 1986, 1991; Koopman 1982, 1993; Flannery 1995). 
Following the taxonomic treatments of Kuroda (1938) and Koopman (1993), 
which are known to be based on examination of numerous specimens, and 
the most recent treatment by Flannery (1995), Pteropus mariannus is a 
widely dispersed species occurring north of the equator in portions of 
Micronesia north to the Japanese Ryukyu Islands. Various authors have 
attributed different numbers of subspecies to P. mariannus. Kuroda 
(1938) and Koopman (1982, 1993) recognize seven subspecies; Flannery 
recognizes three.
    Pteropus fruit bats are well known to be strong fliers and traverse 
long distances (Eby 1991; Palmer and Woinarski 1999; Nelson 2003). 
Evidence that Mariana fruit bats fly between islands in the archipelago 
supports consideration of these bats as a single subspecies made up of 
numerous island populations in the Marianas (Lemke 1986; Service 1990; 
Wiles and Glass 1990; Worthington and Taisacan 1996). The geography of 
the archipelago, as well as the flight capability of fruit bats, 
facilitates interisland exchange. Distances between islands in the 
Mariana archipelago range from 3 to 62 mi (5 to 100 km). Each island in 
the chain is visible from neighboring islands (Wiles and Glass 1990).
    The August 27, 1984, Federal listing (49 FR 33881) of fruit bats 
resident on Guam was based on an assumption that these bats were a 
distinct subspecies isolated from other bat populations in the CNMI. 
However, current evidence exists that large numbers of bats from Rota 
have visited Guam for periods of months. Temporary spikes in the Guam 
fruit bat population were observed in 1992-1993 (from about 350 to 550 
bats) and in 1998 (from about 150 to 760 bats) (Anne Brooke, Service, 
in litt. 2003). These temporary increases lasted for several months. 
More modest but equally sudden increases in the Guam population were 
noted 2 and 4 days following Typhoons Chataan and Pongsona, 
respectively, in 2002 (Dustin Janecke, University of Guam, in litt. 
2003). The most likely explanation is a temporary relocation of bats 
from Rota, which lies 48 mi (77 km) from Guam, is visible from Guam's 
north shore, and harbors one of the largest fruit bat populations in 
the archipelago. For example, the 2002 spike on Guam after Typhoon 
Pongsona was concurrent with an observed dip in fruit bat numbers on 
Rota (Jake Esselstyn, University of Kansas (formerly CNMI Department of 
Fish and Wildlife (DFW)), pers. comm. 2004b). Several other instances 
of apparent immigrations from Rota to Guam documented in the late 1970s 
and 1980s are described in detail by Wiles and Glass (1990). Although 
we cannot be certain that ``visiting'' bats interbreed with resident 
Guam bats during their months on the island, the fact that Mariana 
fruit bats breed throughout the year (Wiles 1983, 1987a) leaves this 
possibility open. The presence of fruit bats on the islands of Tinian 
and Aguiguan, which are close to one another and to Saipan, is 
ephemeral (Worthington and Taisacan 1996), indicating that interisland 
travel likely occurs among these three islands as well.
    An example of likely interisland movement in the northern islands 
of the CNMI comes from Sarigan. Fruit bat surveys on Sarigan documented 
a roughly stable level of approximately 125-235 bats between 1983 and 
2000 (Wiles et al. 1989; Fancy et al. 1999; Wiles and Johnson 2004). In 
2001, surveys estimated 300-400 bats (Wiles and Johnson 2004). 
Recruitment of juvenile bats alone cannot account for this increase, 
and Wiles and Johnson (2004) posit Anatahan, 23 mi (37 km) to the 
south, as the likely source for immigrants. Wiles et al. (1989) twice 
observed individual fruit bats 0.8 mi (2 km) from Guguan, flying south 
in the direction of Sarigan, which lies 39 mi (63 km) away. Anecdotal 
observations of likely transits among other northern islands are 
described in Wiles and Glass (1990) and by other species experts 
(Worthington and Taisacan 1996; Wiles and Johnson 2004).
    Like fruit bats, many other highly mobile vertebrates of Pacific 
Islands, especially birds, are treated as a single species or 
subspecies inhabiting multiple islands in an archipelago (Mayr 1945; 
Pratt et al. 1987; Watling 2001). Immigration rates of perhaps one 
individual per generation could be necessary for an island population 
to maintain genetic homogeneity with the populations on other islands 
(Mills and Allendorf 1996; Wang 2004; Gary McCracken, University of 
Tennessee, pers. comm. 2004). The chances of witnessing such a low rate 
of immigration are slight. The evidence described above for interisland 
movement suggests even greater rates of movement and probable gene flow 
among the fruit bat populations on various islands in the Mariana

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archipelago than the minimum needed to maintain genetic homogeneity.
    Preliminary results of a recent study of genetic variation in a 
similarly gregarious (Pierson and Rainey 1992) and mobile species of 
fruit bat elsewhere in the Pacific provide further, if circumstantial, 
support for the existence of a single subspecies of fruit bats in the 
Marianas. Genetic material collected from the white-collared fruit bat 
(Pteropus tonganus) in Samoa and Fiji shows a lack of genetic isolation 
within island groups (Utzurrum et al. 2000; G. McCracken, pers. comm. 
2004). Little anecdotal observation of interisland movements exists for 
P. tonganus, yet apparently it experiences immigration at sufficient 
intervals to prevent genetic isolation.
    Currently, there are two recognized subspecies restricted to the 
Mariana Islands: the Mariana fruit bat (Pteropus mariannus mariannus) 
and the Pagan fruit bat (Pteropus mariannus paganensis). Other 
subspecies are endemic to other archipelagos and do not occur in the 
Marianas. The taxonomic status of the Pagan fruit bat is questionable. 
Yamashina (1932) collected three male fruit bats and one female from 
the islands of Pagan and Alamagan in 1931, and stated: ``[t]his 
species, as compared to the Pteropus mariannus mariannus that inhabit 
Guam, is distinctly darker in coloration, having brownish wings.'' He 
made no further comparisons, and thus the distinction of this taxon is 
based on a single, equivocal interpretation of the coloration of four 
specimens. Although future studies may confirm the existence of a 
distinct taxon of fruit bats in the northern islands, at this time, 
based on the best available science including peer reviewer comments, 
we do not consider Pteropus mariannus paganensis as distinct from 
Pteropus mariannus mariannus to represent a single taxon.

Habitat

    Mariana fruit bats forage and roost primarily in native forest and 
forage occasionally in coconut (Cocos nucifera) groves and strand 
vegetation (Wiles 1987b; Worthington and Taisacan 1996). Wiles (1987b) 
described six bat roost sites on Guam, all within native limestone 
forest. Major roost trees included Ficus spp. and Neisosperma 
oppositifolia. On Rota, fruit bats used primary and secondary limestone 
forest for roosting and foraging (Glass and Taisacan 1988). At least 
nine tree species were used for roosting, including Elaeocarpus 
sphaericus, Macaranga thompsonii, Guamia mariannae, Hernandia spp., 
Artocarpus mariannensis, Ficus prolixia, Barringtonia asiatica, Randia 
cochinchinensis, and the introduced Theobroma cacao (Glass and Taisacan 
1988). A small bat colony also was observed roosting in Casuarina 
equisetifolia on Aguiguan (Worthington and Taisacan 1996). At least 22 
plant species are used as food sources by the Mariana fruit bat. Food 
items include the fruits of 17 species of plants, especially the native 
Artocarpus mariannensis, Cycas circinalis, Ficus spp., Pandanus 
tectorius, Terminalia catappa, and the introduced Artocarpus altilis 
and Carica papaya; the flowers of seven plants, including the native 
Ceiba pentandra and Erythrina variegata, and the introduced Cocos 
nucifera; and leaf stems and twig tips of Artocarpus spp. (Wiles 1987a; 
Service 1990). Although Mariana fruit bats have been observed to feed 
on and roost in cultivated, introduced food plants, nonnative species 
make up only a small fraction of the plants they use (Wiles 1987b; 
Worthington and Taisacan 1996). Fruit bats are important components of 
tropical forest ecosystems because they disperse plant seeds and 
thereby help maintain forest diversity and contribute to plant 
regeneration following typhoons and other catastrophic events (Cox et 
al. 1992).

CNMI Southern Islands

    The relatively large size and moderate topography of the southern 
islands led to their being, along with Guam, the most heavily populated 
and intensively cultivated islands in the archipelago. All of the 
southern Marianas are hypothesized to have been densely forested when 
first settled by humans some 3,500 years ago (Mueller-Dombois and 
Fosberg 1998). The loss and alteration of native habitats on these 
islands began with prehistoric cultivation, accelerated with the 17th 
century introduction of livestock and mechanized agriculture by 
Europeans, and likely peaked during the mid-20th century with 
landscape-scale habitat conversion by commercial agriculture, military 
infrastructure, and bombardment (Bowers 1950; Fosberg 1960; Stone 
1970). This long continuous and intense human disturbance is reflected 
by the near absence of Mariana fruit bats from Saipan, Tinian, and 
Guam.
    On Saipan and Tinian, agriculture and free-roaming livestock had 
converted much of the islands' forest to fields and pastures as early 
as the 18th century (Barrat 1988 in Stinson et al. 1992). Human 
populations on these islands increased steadily, and virtually all 
arable land was used to grow cash crops or food (Bowers 1950). Sugar 
plantations dominated the landscapes of Saipan, Tinian, and Aguiguan 
prior to World War II (Fosberg 1960). Saipan and Tinian were invaded 
during World War II, and during and after the war, bombing and 
extensive military development resulted in the loss of additional fruit 
bat habitat (Bowers 1950; Fosberg 1960). After the war, Saipan and 
Tinian were estimated to retain 5 and 2 percent native forest cover, 
respectively (Bowers 1950), and these proportions apparently were not 
significantly different in 1982 (Engbring et al. 1986). The 
introduction of nonnative species such as tangantangan for erosion 
control has left these islands dominated by alien vegetation that 
inhibits the growth of native forest (Fosberg 1960; Craig 1993). Feral 
ungulates are present on both islands, resulting in further degradation 
and fragmentation. Finally, Saipan is the most heavily populated and 
industrialized island in the CNMI (CNMI Statistical Yearbook 2001). 
Aguiguan was not invaded during the war, and has retained a greater 
proportion of its native forest (20 percent; Bowers 1950).
    Similar to Saipan and Tinian, large areas of Rota were converted to 
sugar plantations in the early part of the 20th century (Fosberg 1960). 
Rota has more rugged topography, however, and was not invaded during 
World War II. These two factors are thought to explain the greater 
amount of native forest cover (25 percent) remaining on Rota following 
the war (Baker 1946; Bowers 1950). Engbring et al. (1986) estimated 
that roughly 60 percent of Rota's land area supported native vegetation 
in 1982. It is not clear whether Engbring's estimate represents some 
level of native forest recovery since Bowers' (1950) post-war estimate, 
or is a different interpretation and measurement of forest cover.
    Most of Guam's native vegetation has been replaced by land 
development and invasive species. Guam is the population and commercial 
center of the archipelago, and commercial and residential development 
are ongoing. Like the other southern islands, parts of Guam were seeded 
with tangantangan following World War II to control erosion (Fosberg 
1960). Large areas of southern Guam are dominated by savannas; these 
landscapes are thought to have originated as a result of aboriginal 
burning (Fosberg 1960). In 1981, northern Guam, which supports the last 
extensive native forest remaining on the island, was thought to retain 
no more than 37 percent native forest cover (Engbring and Ramsey 1984). 
Feral ungulates are abundant and

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widespread throughout the island and cause significant damage to all 
remaining native forest (Fosberg 1960; Stone 1970; A. Brooke, pers. 
comm. 2004). Lands owned by the U.S. Air Force (Air Force) at Andersen 
Air Force Base in northern Guam include the largest contiguous forested 
areas left in northern Guam; the Air Force permits hunting of feral 
ungulates on parts of the base (U.S. Air Force 2001).

CNMI Northern Islands

    Compared with the history of habitat loss in the southern islands, 
degradation or loss of native forest in the northern islands of the 
CNMI is a recent phenomenon; therefore, these islands have retained 
more habitat to support Mariana fruit bats. Some of the northern 
islands have supported small human settlements, and most of these have 
been occupied only sporadically. Feral ungulates have been present in 
the northern islands only since the mid-20th century. For example, 
Anatahan has had feral goats and pigs for roughly 40 years (Kessler 
1997), and forest degradation and erosion were observed to escalate 
sharply during the 1990s (Marshall et al. 1995; Kessler 2000a; 
Worthington et al. 2001), possibly because feral ungulate damage was 
exacerbated by El Nino-related drought in the late 1990s (Kessler 
2000a).
    Although changes in forest cover were not quantified, evidence from 
point photo monitoring and other land-based photography conducted on 
Anatahan in 1983, 1996, and 2000 documented widespread loss of forest, 
reduced canopy cover in remaining forest, and increased erosion 
resulting from feral ungulate damage (Marshall et al. 1995; Kessler 
1997, 2000a; Worthington et al. 2001). An ungulate eradication project 
was begun in 2002, but was not completed when Anatahan volcano erupted 
in 2003. This eruption further compromised the island's forest habitat, 
and continuing volcanic activity has hindered completion of the 
ungulate eradication project. A large population of feral pigs still 
occurs on the island and some goats remain; aerial hunting for goats is 
ongoing (Curt Kessler, Service, pers. comm. 2004b). Some vegetation 
recovery has been observed as a result of goat control, but an invasive 
alien vine, Mikania micrantha, has spread rapidly and may inhibit the 
growth of native vegetation (C. Kessler, pers. comm. 2004b). This plant 
is known to smother and displace native vegetation on other Pacific 
islands (U.S. Department of Agriculture (USDA) 2004).
    On Pagan, livestock was maintained in captivity by island residents 
until the volcanic eruption in 1981, when the human population was 
evacuated. In the subsequent 23 years, large populations of feral 
goats, pigs, and cattle have become established on the island and have 
caused significant damage (Rice and Stinson 1992; Kessler 1997). The 
degradation and loss of native forest on Pagan is thought to be 
occurring more rapidly on there than on Anatahan because of the added 
impact of cattle, which are absent from Anatahan (Kessler 1997). The 
reductions in fruit bat numbers on Pagan are attributed to feral 
ungulates causing major damage to the native forest and preventing its 
regeneration following the 1981 eruption, large areas especially in the 
northern part of the island being converted to grassland or devegetated 
and eroded (Kessler 1997), and the spread of the invasive tree 
Casuarina equisetifolia in monotypic stands (Rice and Stinson 1992; 
Cruz et al. 2000e). In 1992, Casuarina coverage in the upland areas of 
the island was estimated at roughly 60 percent (Rice and Stinson 1992). 
Although this tree is used for roosting by Mariana fruit bats (C. 
Kessler, pers. comm. 2004b), it does not provide food resources, and it 
likely displaces native forest, as it has done elsewhere in the Pacific 
(Cruz et al. 2000e; USDA 2004).
    Vegetation surveys in 2000 on Agrihan, the third-largest of the 
northern islands, documented damage from feral ungulates in the 30 to 
40 percent of the island that supports forest habitat (Cruz et al. 
2000f). The extremely steep and dissected topography of Agrihan is 
thought to restrict the distribution of feral ungulates as well as 
access by humans, and keep goats and pigs geographically separated 
(Rice et al. 1990; Rice and Stinson 1992), thereby protecting roost 
sites and sufficient forest habitat to support foraging fruit bats.
    Feral goats, pigs, and cattle are present on Alamagan and the 
extent of native forest remaining on the island is limited to ravines 
on the south and west slopes and a small plateau in the center of the 
island (Wiles et al. 1989). Rice (1992) described Alamagan as having 
``one of the worst feral ungulate problems in the CNMI,'' and during 
vegetation surveys in 2000, Cruz et al. (2000b) found the remaining 
forests to be in decline.
    Maug, Asuncion, Guguan, and (since 1998) Sarigan are free of feral 
ungulates, but the small size of these islands and the limited extent 
of their forest habitat ultimately limits the number of fruit bats they 
can support. Maug is only 10 to 14 percent forested (Wiles et al. 
1989), and thus supports little habitat for fruit bats. Forest on 
Asuncion and Guguan is limited to the lower western and southern areas; 
the northern and steep upper parts of these islands are bare volcanic 
ash or grassland (Wiles et al. 1989). Roughly 32 percent or 400 acres 
(ac) (162 hectares (ha)) of Sarigan is forested, but most of this is 
monotypic coconut forest that provides only minimal forage for fruit 
bats; only about 72 ac (29 ha) supports relatively diverse native 
forest that provides both roosting and foraging resources for fruit 
bats (Wiles and Johnson 2004). Although the eradication of ungulates 
from Sarigan and initial vegetation recovery may play a role in 
increased numbers of fruit bats on the island, invasive, alien plants 
such as tangantangan (Leucaena leucocephala) and Operculina ventricosa 
also are present on the island and may impede the recovery of native 
forest over the long term (Kessler 2000b). These plants are known to 
degrade native vegetation in the Mariana Islands and elsewhere in the 
Pacific (USDA 2004).

Landownership of Fruit Bat Habitat in the Mariana Islands

    Most of the known fruit bat roost sites in the Mariana Islands are 
located on public lands. On Guam, the single remaining roost and most 
fruit bat foraging habitat is found on U.S. military lands; some 
foraging habitat occurs on private lands and lands belonging to the 
Government of Guam (Wiles 1998). The Air Force controls access to 
Andersen Air Force Base in northern Guam, and the high security and 
frequent patrols practiced on base effectively create a refugium for 
fruit bats (Morton 1996). The remote and relatively pristine area where 
the roost is located was set aside by the military in 1973 as a 
research natural area; access to and activities in this area are 
tightly restricted, but no brown treesnake control currently takes 
place specifically at the roost site (Air Force 2001). Service and 
Government of Guam wildlife biologists and authorized researchers are 
permitted access to the area and to the colony to monitor and conduct 
research on fruit bats. Similarly, the U.S. Navy (Navy) and the Service 
restrict access to their lands, which include native forest that 
provides foraging habitat for the fruit bat.
    The remaining roost site is managed as part of the Guam National 
Wildlife Refuge (Refuge) overlay under a cooperative agreement with the 
Air Force. The Refuge was created on October 1, 1993, with additional 
lands (overlay portion) incorporated in 1994 by cooperative agreements 
between the

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Service, the Air Force and the Navy. The establishment and management 
of the overlay portion of the Refuge on Navy and Air Force lands 
provides a commitment by the three agencies to develop coordinated 
programs centered on the protection of endangered and threatened 
species and other native flora and fauna. Active implementation of such 
programs by these agencies contributes to the continued survival of the 
Mariana fruit bat on Guam, as important foraging and roosting habitat 
is located within the Refuge boundaries. However, the lack of brown 
treesnake control in the immediate area where the fruit bats roost is a 
serious deficiency in existing programs to protect endangered species 
on the overlay refuge.
    There is no U.S. Government-owned land in the CNMI, but the Navy 
leases Farallon de Medinilla and part of Tinian. All other public lands 
are administered by the CNMI government. Saipan has little public land 
that is not leased and developed, but a few areas still support native 
forest that is occasionally used by fruit bats. Tinian has large tracts 
of public land that contain small stands of native forest suitable for 
bats, and a large portion of public land on the northern end of the 
island is under lease to the Navy for military activities (Lusk et al. 
1997). All of Aguiguan is owned by the CNMI government. Approximately 
60 percent of the land on Rota is publicly owned, although much of this 
has been leased to private individuals. The primary roosting areas on 
Rota are on Commonwealth lands, but some private lands still retain 
native limestone forest that may support fruit bats. The northern 
islands are mostly public lands, with some land developed as small 
homestead lots.

Population Surveys and Status

    Obtaining accurate estimates of fruit bat populations in Pacific 
archipelagos depends on regular monitoring, standardized survey 
methods, and consideration of the unique ecology and physiographic 
environment of bat populations in various island groups (Utzurrum et 
al. 2004). The difficult terrain of the Mariana Islands, remote 
location of the northern islands of the CNMI, and the high costs 
associated with transits of the island group by sea and aerial surveys 
of individual islands have hindered the establishment of a standard 
monitoring program for the archipelago.
    No known historical records exist to document the status of the 
Mariana fruit bat prior to the 20th century. The history of fruit bat 
surveys and changes in numbers summarized below represent a variety of 
methods and analyses. Archipelago-wide surveys were conducted in 1983 
(Wiles et al. 1989) and 2001 (Johnson 2001).
    The relatively isolated northern islands support the majority of 
the fruit bats in the archipelago, but because of their remote 
location, these islands have not been surveyed as frequently as the 
southern islands. Individual surveys have been conducted on several of 
the southern islands at relatively frequent intervals, and 
comprehensive surveys of the northern islands were conducted in 1983, 
2000, and 2001 (Wiles et al. 1989; Cruz et al. 2000a-f; Johnson 2001). 
Opportunistic surveys have also occurred sporadically throughout the 
archipelago. The methods used in the northern islands in 2001 were 
significantly different from those used in 1983 and 2000; we therefore 
consider only Wiles et al. (1989) and Cruz et al. (2000a-f) for 
purposes of comparison (Table 1). A conservative interpretation of this 
comparison indicates a decline between 1983 and 2000, especially on the 
two islands that supported the largest numbers of fruit bats in the 
archipelago 20 years ago (Table 1).
    Two of the northern islands are not included in this table: Uracas, 
the most northerly, where fruit bats are not known to occur; and 
Farallon de Medinilla, where fruit bats have been observed on only one 
occasion. See text and Table 2 for information about additional and 
more recent surveys and observations of fruit bats on the southern 
islands of the CNMI and Guam, and on Farallon de Medinilla, Anatahan, 
Sarigan, and Pagan.

                    Table 1.--Summary of Mariana Fruit Bat Survey Results: Minimum Estimates
----------------------------------------------------------------------------------------------------------------
                Island                      Area  Sq. mi (Sq. km)              1983 \1\              2000 \2\
----------------------------------------------------------------------------------------------------------------
Maug..................................  0.8 (2.0)                     <25                                  (\3\)
Asuncion..............................  2.9 (7.4)                     400                                  (\3\)
Agrihan...............................  18.3 (47.4)                   1,000                                1,000
Pagan.................................  18.4 (47.7)                   2,500                                1,500
Alamagan..............................  4.3 (11.0)                    0                                      200
Guguan................................  1.5 (4.0)                     400                                    350
Sarigan...............................  1.9 (5.0)                     125                                    200
Anatahan..............................  12.5 (32.3)                   3,000                                1,000
                                       -------------------------------
    Total (Northern Islands)..........  ............................  7,450                       ..............
    [Total six islands]...............  ............................  [7,025]                              4,250
                                       -------------------------------
Saipan................................  47.5 (122.9)                  <50                                  (\3\)
Tinian................................  39.3 (101.8)                  <25                                  (\3\)
Aguiguan..............................  2.7 (7.0)                     <10                                150-200
Rota..................................  37.0 (95.7)                   800-1,000                            (\3\)
Guam..................................  212.0 (549.0)                 425-500                              (\3\)
                                       -------------------------------
    Total (All Islands)...............  ............................  8,760-9,035                           N/A
----------------------------------------------------------------------------------------------------------------
\1\ Wiles et al. 1989. Dates: August 17-September 10, 1983; 1-4 days/island. Count methods: Evening dispersal
  counts at colonies; evening station counts of solitary fruit bats.
\2\ Cruz et al. 2000a-f. Dates: June 4-August 16, 2000; 7-9 days/island. Count methods: Evening dispersal counts
  at colonies, evening and morning station counts of solitary fruit bats.
\3\ Not surveyed.


[[Page 1197]]

Status of CNMI Southern Islands

    Fruit bats on the southern islands of the CNMI, Tinian, Saipan, 
Aguiguan, and Rota were not surveyed prior to the 1970s, but historical 
accounts indicate that fruit bats once were much more common on these 
islands than they are now. Schnee (1911) reported that bats were 
commonly seen and heard on Saipan, where they were heavily hunted by 
local residents. The Navy restricted civilian access to the northern 
part of Saipan until the early 1970s, effectively providing fruit bats 
with protected roost sites. The fruit bat population on Saipan was 
observed to decline rapidly after the Navy turned over the control to 
the CNMI government and access to the whole island became unrestricted 
(Wiles et al. 1989). Observations during the 1980s and 1990s suggested 
that the Saipan population was small; typically fewer than 50 bats were 
observed (Lemke 1984; Wiles et al. 1989; Wiles 1996; Worthington and 
Taisacan 1996). Surveys on Saipan in 2001 estimated that roughly 50 
bats were present (Johnson 2001).
    Fritz (1901) reported a large number of bats on Tinian in 1900 and 
Fritz (1904) reported that bats were common on all the southern 
islands. Fruit bats are only occasionally seen on Tinian today 
(Marshall et al. 1995; Krueger and O'Daniel 1999; Johnson 2001). 
Observations during the 1990s suggested that the presence of bats on 
Tinian was intermittent and their numbers were low (Lemke 1984; Wiles 
1996; Worthington and Taisacan 1996). Surveys on Tinian conducted in 
2001 found no fruit bats (Johnson 2001). In 1995, between 100 and 125 
bats were believed present on Aguiguan (Wiles 1996). During a 10-day 
visit in 2003, however, no fruit bat colonies were observed on Aguiguan 
despite extensive coverage, and only a few individual fruit bats were 
seen (J. Esselstyn, pers. comm. 2004a).
    The fruit bats on Rota have been surveyed on a regular basis by a 
large number of workers since 1986, using methods described by Stinson 
et al. (1992): primarily evening dispersal counts (EDCs), with some 
station counts of solitary or extracolonial bats and direct counts of 
colonial roosts (Glass and Taisacan 1988; Stinson et al. 1992; 
Worthington and Taisacan 1995, 1996; Johnson 2001; J. Esselstyn in 
litt. 2003, pers. comm. 2004a). This monitoring effort has yielded 
numbers that vary widely both intra- and interannually (e.g., Glass and 
Taisacan 1988; Worthington and Taisacan 1995, 1996). Analysis of the 
census data on Rota is underway (Laura Williams, CNMI DFW, pers. comm. 
2004).
    Fruit bat numbers declined following Typhoon Roy in 1988 from an 
estimated 2,400 animals to just under 1,000 (Worthington and Taisacan 
1996). Prior to Typhoon Pongsona in 2002, however, the Rota bat 
population had risen back to approximately 2,500 (J. Esselstyn, in 
litt. 2003). In the months following the storm, repeated surveys 
indicated that numbers had again declined sharply to about 600 (J. 
Esselstyn, pers. comm. 2004b). Continued surveys of Rota's fruit bats 
indicate that the population was once again rising in 2004; in April it 
was estimated at roughly 1,500 animals (J. Esselstyn, pers. comm. 
2004a, 2004b). The Rota population fluctuates and may be resilient, but 
severe storms at short intervals could erode this resilience. The most 
recent available estimate of fruit bat numbers on Rota is 1,100 (C. 
Kessler, pers. comm. 2004b). This estimate was made in May 2004, prior 
to Typhoon Chaba. The bats from Rota are believed to move among the 
southern islands, and this population thus is considered to be 
important to the long-term stability of fruit bats in the southern 
islands of the Mariana archipelago (Wiles and Glass 1990), and to the 
existence of the colony on Guam (Catherine Leberer, Guam Division of 
Aquatic and Wildlife Resources (DAWR), in litt. 2004).

Status of CNMI Northern Islands

    The 1983 survey of the northern islands resulted in an estimate of 
7,450 bats for Anatahan, Sarigan, Guguan, Alamagan, Pagan, Agrihan, 
Asuncion, and Maug (Wiles et al. 1989, Tables 1 and 2). Because field 
observation of Mariana fruit bats indicate that this species is 
gregarious and typically roosts in large colonies during the day, this 
and subsequent surveys focused on locating colonies. Wiles et al. 
(1989) located colonies by circumnavigating islands by boat, traversing 
portions of each island on foot, and interviewing residents on islands 
with human inhabitants. EDCs were conducted at each colony beginning at 
1 to 3 hours before nightfall and continuing until complete darkness. 
These surveys were carried out by observers placed so that fruit bats 
departing the colony were silhouetted against the sky or the ocean. 
Rates of fruit bat departure from colonies were observed to be greatest 
between 10 and 40 minutes after sunset, but because departures 
continued after darkness when they are difficult to see, EDCs represent 
minimum counts (Wiles et al. 1989). In addition, evening counts of 
solitary or extra-colonial bats were made from vantage points 
determined to overlap least with the apparent dispersal trajectory of 
colony bats. Islandwide estimates were based on the number of fruit 
bats recorded, island size, extent of forest cover and abundance and 
diversity of food-plant species (Wiles et al. 1989).
    Surveys of the northern islands undertaken in 2000 (Cruz et al. 
2000a-f) employed a combination of the same methods used by Wiles et 
al. (1989) in 1983 and, on Anatahan, by Worthington et al. (2001) in 
1995: land- and sea-based colony searches, EDCs, station-counts of 
extra-colonial bats, and direct day-time counts at roosts. On each 
island they visited, Cruz et al. (2000a-f) spent periods conducting 
fruit bat surveys equal to or greater than periods spent by Wiles et 
al. (1989) on the same six islands. The individual island-wide 
estimates of Cruz et al. (2000a-f) thus are comparable to those of 
Wiles et al. (1989), but owing to logistical and fiscal constraints, 
Cruz et al. (2000a-f) did not visit Asuncion and Maug. The 2000 surveys 
yielded an estimate of 4,450 fruit bats for the 6 northern islands they 
visited (Cruz et al. 2000a-f). The 1983 surveys yielded an estimate of 
7,025 fruit bats for the same six islands (Wiles et al. 1989). A 
conservative interpretation of these data indicates a 37 percent 
decline in fruit bat numbers between 1983 and 2000 among these six 
northern islands.
    The majority of this decline was recorded on two of the three 
largest northern islands, Anatahan (12.5 square mi (32.3 square km)) 
and Pagan (18.4 square mi (47.7 square km)), which together harbored 
roughly 70 percent of the archipelago's fruit bats in the 1980s (Wiles 
et al. 1989). These two islands, which were estimated to support a 
total of 5,500 fruit bats in 1983, were estimated to have only 2,500 
fruit bats in 2000; approximately a 45 percent decline since 1983 (Cruz 
et al. 2000d, 2000e). These declines may be related to severe habitat 
damage caused by feral ungulates (Cruz et al. 2000d, 2000e; Kessler 
2000a; see discussion in Background, Habitat section).
    On Anatahan, surveys identified about 3,000 fruit bats in 1983 
(Wiles et al. 1989), 1,902-2,136 individuals in 1995 (Marshall et al. 
1995; Worthington et al. 2001), and roughly 1,000 in 2000 (Cruz et al. 
2000d; Kessler 2000a). In conjunction with the ungulate eradication 
project, fruit bats on Anatahan have been surveyed frequently since 
2002. Aerial (helicopter) surveys were conducted in May 2002; February, 
March, April, August, October, and December 2003; and January, 
February, March, July, and September 2004. These surveys are

[[Page 1198]]

performed over 2 days, with 4 hours spent over the island each day. 
Coverage of the island during each survey is complete. Fruit bat 
colonies are rapidly reconnoitered to verify known roost sites and 
identify new ones, colonies are counted and mapped, and individual bats 
in flight also are counted. After the volcanic eruption in May 2003, 
the island's state of devegetation facilitated accurate location of all 
colonies (C. Kessler, in litt. 2003, pers. comm. 2004c). In 2002 and 
early 2003, estimates of the island's bat population ranged from 950 to 
1,250 (C. Kessler, in litt. 2003). Following Anatahan's volcanic 
eruption in May 2003, aerial surveys conducted in August, October, and 
December of 2003 yielded estimates of 350-700 bats, and in January and 
February of 2004, bat numbers were estimated at 500-600 and 550-650, 
respectively (C. Kessler, in litt. 2003, pers. comm. 2004c). Surveys in 
March, July, and September of 2004 yielded increased estimates of about 
1,000-1,200 bats (C. Kessler, pers. comm. 2004c). This localized 
increase in fruit bat numbers over a short period of time (1 to 1.5 
years) was concomitant with some vegetation recovery, and indicates 
that Anatahan's population may have reached its pre-eruption level, 
whether the source of the additional bats is immigration, recruitment 
of newly volant (flying) young, or both (see Summary of Factors 
Affecting the Species section).
    On Pagan, fruit bat numbers were estimated at 2,500 in 1983 (Wiles 
et al. 1983), and at roughly 1,500 in 1999 and 2000 (Cruz et al. 
2000e). On the third-largest northern island, Agrihan (18.3 square mi 
(mi\2\) (47.4 square km (km\2\)), results of surveys in 1983 and 2000 
indicate that fruit bat numbers have been stable at about 1,000 
individuals (Wiles et al. 1989; Cruz et al. 2000f).
    The remaining northern islands with fruit bat populations, Maug, 
Asuncion, Alamagan, Guguan, and Sarigan, all are less than 5 square mi 
(13 square km) (Table 1), and harbor from 100 to 500 bats (Cruz et al. 
2000a, b, c). Sarigan, the next island north of Anatahan, has been 
surveyed more frequently in recent years in conjunction with the 
ungulate eradication there. A 1997 survey of Sarigan estimated the 
population at 170 fruit bats, and a 1999 survey resulted in an estimate 
of 150-200 individuals (Wiles 1999). Surveys between 1983 and 2000 on 
Sarigan estimated populations of approximately 125-235 bats (Wiles et 
al. 1989; Fancy et al. 1999; Wiles and Johnson 2004). In 2001, surveys 
estimated 300-400 bats (Wiles and Johnson 2004). The observed increase 
on Sarigan may reflect a response to the recovery of forest vegetation 
after the eradication of feral goats and pigs from the island in 1998 
(Zoology Unlimited 1998). As described above in the discussion of 
interislands movements, the increase in 2001 may also reflect 
immigration to Sarigan from Anatahan, 23 mi (37 km) to the south, as 
well as recruitment of newly volant young (Wiles and Johnson 2004). The 
potential for increase in fruit bat numbers on Sarigan is thought to be 
limited, however, by the island's small size (1.9 mi\2\ (4.9 km\2\)), 
the small extent of forest habitat (as described above, in the Habitat 
section), and the prevalence of monotypic stands of coconut, which 
provide only minimal forage habitat for fruit bats (Wiles and Johnson 
2004; G. Wiles, Washington Department of Fish and Wildlife (formerly 
CNMI DFW), pers. comm. 2004).

Guam

    On Guam, the sighting of fruit bats was considered to be ``not * * 
* uncommon'' in the 1920s (Crampton 1921). However, by 1931, bats were 
uncommon on Guam, possibly because of the introduction of firearms 
(Coultas 1931). Woodside (1958) reported that in 1958, the Guam 
population was estimated to number no more than 3,000, although the 
method used to make this estimate is not known (Utzurrum et al. 2004). 
This estimate had dropped by an order of magnitude, to between 200 and 
750 animals by 1995, in part because of predation by the introduced 
brown treesnake (Wiles et al. 1995; Wiles 1996). During 1998, bat 
populations on Guam varied from an estimated low of 210-245 to a high 
of 910-980 bats (Wiles 1998), and in 1999, bat numbers ranged from an 
estimated low of 199-235 to a high of 327-371 (Wiles 1999). The most 
recent surveys on Guam put the bat population at fewer than 100 
individuals (D. Janecke, in litt. 2003; A. Brooke, in litt. 2003). 
Predation by brown treesnakes on non-volant young probably prevents 
recruitment of juvenile bats on Guam (Wiles et al. 1995; Wiles 1996; G. 
Wiles, in litt. 2003).

Previous Federal Action

    The Mariana fruit bat (Pteropus mariannus mariannus) was listed as 
endangered in 1984 on Guam (49 FR 33881). It was listed as a subspecies 
found only on Guam. More recent research over the years since this 
subspecies was listed indicates that Pteropus mariannus mariannus is 
not a subspecies endemic only to Guam but the Guam population is part 
of a subspecies including populations of bats on other islands that 
interact with each other (movement between islands). We believe that it 
is appropriate to list these bat populations in Guam and CNMI as one 
subspecies (63 FR 14641).
    All the bat populations on Guam and in the CNMI are facing a number 
of threats, with most populations declining. We published a proposed 
rule on March 26, 1998 to reclassify the Mariana fruit bat on Guam from 
endangered to threatened and list all the bat populations on Guam and 
other CNMI islands as one subspecies throughout its range as threatened 
(63 FR 14641, 69 FR 30277).
    We proposed to list the subspecies as threatened because we wanted 
to: (1) Simplify actions and expenditures. We could affect a 
downlisting for the population on Guam with little or no additional 
time and expense in conjunction with proposing to list the subspecies 
throughout its range, instead of taking a separate action to downlist 
the population on Guam; and (2) acknowledge a change in taxonomy. When 
we originally listed the population on Guam, we believed it to be a 
separate subspecies endemic only to Guam with a declining population 
and significant threats to it which merited endangered status. However, 
by including the other populations in the listing, we are evaluating a 
larger number of bats with a wider distribution, although threats to 
each population remain. Hence, we proposed threatened status for the 
entire population, instead of having one population as endangered and 
the others as threatened.
    In that proposed rule, we included a detailed history of Federal 
actions completed prior to the publication of the proposal. The public 
comment period closed on May 11, 1998 (63 FR 14641) and was reopened 
from May 29, 1998, through July 10, 1998 (63 FR 29367) to accommodate 
requests for public hearings. We designated critical habitat for the 
Mariana fruit bat on Guam in a final rule published in the Federal 
Register on October 28, 2004 (68 FR 62944). Pursuant to a settlement 
agreement approved by the U.S. District Court for the District of 
Hawaii on August 21, 2002, we must make a final listing decision on the 
Mariana fruit bat and submit the final rule to the Federal Register by 
December 31, 2004. See Center for Biological Diversity v. Norton, Civil 
No. 99-00603 (D. Haw.).

Summary of Comments and Recommendations

    In the proposed rule published on March 26, 1998 (63 FR 14641), we 
requested that all interested parties submit written comments on the

[[Page 1199]]

proposal. We also contacted appropriate Federal, Territorial, and 
Commonwealth agencies, scientific experts and organizations, and other 
interested parties and invited them to comment on the proposal. 
Newspaper notices were published in the Marianas Variety (Saipan, CNMI) 
and Pacific Daily News (Guam), inviting general public comment and 
attendance at public hearings. We held public hearings on June 24, 
1998, on Saipan and June 25, 1998, on Rota.
    We reopened the public comment period on May 27, 2004 (69 FR 
30277), to permit additional public review. In order to address any 
additional comments received during the reopened comment period, and 
meet the court order to submit to the Federal Register a final listing 
decision for the Mariana fruit bat no later than December 31, 2004, we 
reopened the comment period for 30 days, until June 28, 2004. The 
reopened comment period (and associated notifications in local media 
and via direct mailing) gave interested parties additional time to 
consider the information in the proposed rule and provide comments and 
new information.
    During the first comment period in 1998, we received 13 written 
comments, including those submitted at the public hearings. During the 
reopened comment period in 2004, we received four additional written 
comments, including one from a Government of Guam agency, and one from 
a CNMI government agency. Several individuals or groups submitted 
comments in both the original and the reopened comment periods, or 
during hearings and later in writing. Of those comments received in 
1998, eight opposed listing in the CNMI, one opposed listing in the 
CNMI and opposed downlisting on Guam, one opposed downlisting on Guam, 
one opposed downlisting on Guam but was in favor of listing in the 
CNMI, and one supported listing in the CNMI. In addition to several 
private citizens, the CNMI Governor, Director of the DFW, Rota DLNR 
Resident Director, Rota Mayor, and CNMI Senator Thomas P. Villagomez 
all opposed the proposal. The Air Force supported listing the fruit bat 
as threatened throughout the archipelago, but also stated that 
reclassification from endangered to threatened on Guam would be 
``misleading and confusing to the public,'' and cited an article in the 
local press that misrepresented a temporary influx of fruit bats from 
Rota as an increase in the Guam population (Thomas Churan, Air Force, 
in litt. 1998; also see Issue 15, below). The Air Force also expressed 
its belief that the Mariana fruit bat is more susceptible to 
extirpation on Guam than in the CNMI because of the presence of the 
brown treesnake there, and recommended that the fruit bat retain its 
status as endangered on Guam (T. Churan, in litt. 1998). The Mariana 
Audubon Society supported listing all bats in the Mariana archipelago 
as endangered rather than threatened. Three of the four parties that 
submitted comments during the reopened comment period in 2004 supported 
the listing, including the DAWR. The CNMI DFW opposed the listing.
    This final rule has been revised and updated to reflect the 
pertinent comments and information received during the comment periods. 
Comments of similar nature are grouped under a single issue. In 
addition, we considered and incorporated into the final rule all 
appropriate information obtained through the public comment period.

Peer Review

    In 1998, in accordance with our peer review policy published on 
July 1, 1994 (59 FR 34270), we solicited opinions from four individuals 
who have expertise with the species and the geographic region where the 
species occurs, and are familiar with conservation biology principles. 
We received written comments from two experts and incorporated their 
information into the final rule. One peer reviewer described the 
threats posed to the bats on Guam by brown treesnake predation and 
habitat destruction by feral ungulates. This reviewer did not include 
any professional judgment about movement of bats between islands, but 
has published peer-reviewed literature containing information that 
supports interisland exchange. The other expert expressed agreement and 
knowledge that there is interisland exchange.
    In 2004, we solicited additional scientific peer review of the 
proposed rule from eight specialists, including one of the two who 
provided peer review in 1998. Of these, five responded and provided 
additional factual information, including recent survey results, the 
impact of typhoons and illegal hunting on fruit bats in the southern 
islands, and recent genetic studies of other Pteropus species elsewhere 
in the Pacific. Reviewers also provided citations for literature, 
corrections on minor factual issues, and input on interpretation of the 
existing information.
    One reviewer provided a synopsis of changes in fruit bat numbers 
over the past 10-20 years on individual islands in the archipelago and 
noted declines on Guam, Anatahan, and Pagan. This synopsis was based 
partly on the reviewer's own research and partly on the work of others. 
Based on 19 years of fruit bat research, surveys, and personal 
observations in the Mariana Islands while employed as a Senior 
Biologist with the Guam Division of Aquatic and Wildlife Resources, 
this reviewer (who also authored the original recovery plan for the 
Mariana fruit bat on Guam, agency reports, and numerous peer-reviewed 
research papers on the Mariana fruit bat (e.g., Wiles and Payne 1986; 
Wiles 1987a, b; Wiles et al. 1989; Wiles and Glass 1990; Wiles 1992; 
Wiles et al. 1995; Wiles and Johnson 2004) emphasized three major 
threats to Mariana fruit bats: illegal hunting (described as 
``chronic'' on Rota), habitat destruction by feral ungulates, and brown 
treesnake predation. Another reviewer, a biologist who spent two years 
monitoring fruit bats on Rota and elsewhere in the CNMI for the CNMI 
DFW, provided specific information about firsthand observations and 
evidence of illegal hunting of fruit bats on Rota after Typhoon 
Pongsona, described reports received of numerous other illegal hunting, 
and provided survey information documenting post-typhoon decline in 
fruit bats on Rota and subsequent increase in numbers. Three reviewers, 
two of whom hold doctorates based on research on the biology and 
ecology of island fruit bats, and one of whom is currently conducting a 
graduate research project on fruit bats on Guam, expressed their 
professional opinions that anthropogenic disturbances such as illegal 
hunting and habitat loss are likely to be significant threats to the 
Mariana fruit bat, and that these disturbances are periodically 
exacerbated by severe storms.
    Two reviewers cited their own observations and those of other 
workers that indicated likely interisland movements between Sarigan and 
Anatahan and between Rota and Guam, and another reviewer cited 
information collected by others indicating likely interisland movement 
in the archipelago. Three of the five reviewers provided information 
and professional opinion that supported our treating all fruit bats 
occurring in the Mariana archipelago as a single subspecies, Pteropus 
mariannus mariannus, as described in the proposed rule; the other two 
expressed concern about the possible occurrence of genetically isolated 
populations within the range of fruit bats in the Mariana Islands. Two 
reviewers expressed reservations about treating all fruit bats in the 
archipelago

[[Page 1200]]

as one taxon without empirical data from genetic or radio-telemetry 
studies. However, one of these reviewers also described unpublished 
genetic research on fruit bats in Polynesia that indicates a lack of 
within-archipelago genetic structure in a widespread species that 
shares social and behavioral traits with the Mariana fruit bat.
    Issue 1: The Service lacks adequate data to assess the population 
status of Mariana fruit bats. Comprehensive surveys are required to 
determine the status of Mariana fruit bats in the northern islands.
    Our Response: In this case, we believe existing data are adequate 
to assess the overall status of the Mariana fruit bat. Subsequent to 
listing, two additional multi-island surveys of bats in the Mariana 
Islands have been conducted. One of these included six of the 10 
northern islands (Cruz et al. 2000a-f) and yielded data comparable to 
those collected in 1983 by Wiles et al. (1989). The other conducted in 
2001 (Johnson 2001) included all of the islands in the archipelago but 
employed methods that precluded direct comparison with other surveys. A 
conservative interpretation of these data indicate that bat numbers 
have declined on the two islands, which historically had large numbers 
of fruit bats in the archipelago.
    Issue 2: The Service's evidence of bats moving between islands was 
inadequate or only anecdotal, and without empirical evidence of 
interisland movement, a determination that all fruit bats in the 
Mariana Islands belong to the same subspecies is premature. 
Fluctuations in bat numbers, particularly on Guam, may be caused by 
births.
    Our Response: Evidence for the movement of bats between islands in 
the Mariana archipelago is discussed in the Background subsection 
above. The large fluctuations in the Guam bat population over a short 
period of time (Wiles 1998; A. Brooke, in litt. 2003) coupled with a 
low reproductive rate make it unlikely that changes in the Guam 
population reflect recruitment from births. Predation by brown 
treesnakes largely precludes the recruitment of young bats into the 
Guam population (Pierson and Rainey 1992; Wiles 1987a; G. Wiles in 
litt. 2003).
    Issue 3: Long term survey data from Rota indicate natural 
fluctuations in fruit bat numbers on various timescales. Archipelago-
wide surveys and the apparent decline they document may not account for 
these natural fluctuations.
    Our Response: To date, we are aware of no analysis of survey data 
from Rota that: (1) Demonstrates a correlation between variation in 
fruit bat numbers and some other natural cycle, or (2) controls for the 
hunting and other human disturbance.
    Issue 4: CNMI government agencies feel the Service overstated the 
illegal hunting problem, and stated that the CNMI DFW is instituting 
law enforcement reforms, and the CNMI government is committed to the 
enforcement of wildlife regulations. In contrast, most peer reviewers 
identified illegal hunting and lack of enforcement as a significant 
threat to the Mariana fruit bat, especially in the CNMI, and an 
official from Guam DAWR expressed concern that recruitment of immigrant 
bats to Guam is threatened by illegal hunting on Rota.
    Our Response: We appreciate the CNMI DFW's commitment to law 
enforcement. We acknowledge that data on illegal hunting is difficult 
to obtain and assess, and that most of the information regarding 
illegal hunting is anecdotal. We have numerous documented observations 
and reports of illegal hunting incidents in the CNMI (e.g., Arnold 
Palacios, CNMI DWF, in litt. 1990; T. Eckhardt, Service, in litt. 1998; 
J. Esselstyn, pers. comm. 2004a; C. Kessler, pers. comm. 2004a). We 
address the threat to the Mariana fruit bats from illegal hunting in 
Factor B in the Summary of Factors Affecting the Species section.
    Issue 5: The Service was selective in its presentation of the 
impacts of feral animals on Mariana fruit bats, presenting it in a poor 
light to justify listing. The Service did not consider the feral animal 
eradication project on Sarigan, and failed to note that the CNMI DFW 
has an existing federally funded program addressing feral animal damage 
(Feral Animal Monitoring and Management (Project No. W-1-R-1-11; Job 
number 2)).
    Our Response: We have incorporated the results of the Sarigan Feral 
Animal Control Project (Zoology Unlimited 1998) into this final rule 
and discuss the threats posed to fruit bats by feral animals (see 
discussion in the Background section, and Factor A in the Summary of 
Factors Affecting the Species section). Although DFW's Feral Animal 
Monitoring and Management Program has included survey of feral animals 
on many of the northern islands and involvement in several other 
projects, current DFW projections indicate that sufficient funding will 
not be available to complete the eradication of feral ungulates from 
Anatahan, and lack of material support will prevent the implementation 
of plans for feral animal control in the CNMI (L. Williams, pers. comm. 
2004).
    Issue 6: Present CNMI Coastal Resources Management (CRM) and DLNR 
land use regulations adequately protect Mariana fruit bat habitat 
(limestone forest) from development, as exemplified by the 
modifications required for construction of the Rota Resort and Country 
Club. Habitat is also being protected through island-wide master 
planning and through implementation of habitat conservation plans 
(HCPs) on Saipan and Rota.
    Our Response: We support the use of local land use regulations to 
promote the conservation of the Mariana fruit bat and its habitat. 
However, the best measure of their past effectiveness in protecting the 
Mariana fruit bat is the success of these regulations in maintaining 
the integrity of native limestone forest systems in the CNMI, 
particularly in the southern islands where development pressures are 
greatest. Direct and secondary effects of human activity continue to 
cause alteration of native forest areas despite these protections.
    Through the Act's section 10 and HCP planning process, listed 
species may be lawfully taken and measures implemented to reduce 
activity impacts on the species and its habitat. Two HCPs are currently 
under development on CNMI and, if completed and implemented, should 
contribute to fruit bat conservation. The successful completion of 
these HCP projects in the CNMI is not sufficiently certain to consider 
them in making this listing decision. See our Policy for Evaluation of 
Conservation Efforts When Making Listing Decisions (PECE policy) (68 FR 
15100, March 28, 2003).
    Issue 7: The Service did not account for actions by the CNMI 
government to control the brown treesnake, thereby decreasing the 
threat of this factor to the Mariana fruit bat.
    Our Response: We recognize that ongoing actions on Guam, Saipan, 
Tinian, and Rota are important and reduce the threat of accidental 
introduction of the brown treesnake. The U.S. Department of the 
Interior (DOI) Office of Insular Affairs (OIA), U.S. Department of 
Defense (DOD), USDA Wildlife Services, Service, Government of Guam, 
CNMI, and State of Hawaii are working together regionally to control 
brown treesnakes, particularly around transport centers (OIA 1999). The 
OIA and DOD actively fund research into methods of controlling snakes 
on Guam, in part to reduce the threat of introduction to other Pacific 
islands (OIA 1999). Both the CNMI DFW and Guam DAWR conduct brown 
treesnake public awareness educational campaigns

[[Page 1201]]

consisting of school presentations, news releases, workshops, and 
poster/pamphlet distribution (Perry et al. 1996), and the CNMI 
maintains a snake reporting hotline (Nate Hawley, CNMI DFW, pers. comm. 
2004a). In 1996, the CNMI became a signatory of the Memorandum of 
Agreement (MOA) between the governments of Hawaii, Guam, and the CNMI, 
and individual Federal government agencies concerned with brown 
treesnake eradication and control (DOI et al. 1993; DOI et al. 1996). 
This MOA commits the CNMI to a proactive brown treesnake program and 
allows the CNMI to apply for funding from the allotment of money 
appropriated by the U.S. Congress each year for brown treesnake control 
and eradication (OIA 1999).
    Despite ongoing efforts, evidence exists that treesnakes are 
present on Saipan. A concrete barrier completed in 2004 at the 
commercial port on Saipan aids in the prevention of new introductions 
from Guam, but this barrier does not address the problem of the 
treesnakes already present on the island. The presence of brown 
treesnakes on Saipan poses a threat to the recovery of the fruit bat 
population there until the treesnakes are controlled throughout the 
island or are eradicated.
    On Tinian, brow