(DRAFT) - Taxonomy
Species BAT, FRUIT, MARIANA
Species Id ESIS051005
Date 14 MAR 96
TAXONOMY
NAME - BAT, FRUIT, MARIANA
OTHER COMMON NAMES - BAT, FRUIT, MARIANA;BAT, FRUIT, MARIANAS; BAT, FRUIT, MARIANNE; FOX, FLYING, MARIANA; FOX, FLYING and MARIANAS; FANIHI
ELEMENT CODE -
CATEGORY - Mammals
PHYLUM AND SUBPHYLUM - CHORDATA,
CLASS AND SUBCLASS - MAMMALIA,
ORDER AND SUBORDER - CHIROPTERA,
FAMILY AND SUBFAMILY - PTEROPODIDAE,
GENUS AND SUBGENUS - PTEROPUS,
SPECIES AND SSP - MARIANNUS, MARIANNUS
SCIENTIFIC NAME - PTEROPUS MARIANNUS MARIANNUS
AUTHORITY -
TAXONOMY REFERENCES -
COMMENTS ON TAXONOMY -
Mariana Fruit Bat
Pteropus mariannus mariannus Desmarest, 1822
KINGDOM: Animal GROUP: Mammal
PHYLUM: Chordata CLASS: Mammalia
ORDER: Chiroptera FAMILY: Pteropodidae
The Mariana fruit bat is a medium-sized member of the genus
Pteropus. Ranges for body measurements of adults and subadults are:
head-rump length, 195 to 240 mm; forearm length, 134 to 154 mm;
wingspread, 860 to 1065 mm; and body weight, 330 to 577 grams (01,02).
Males are slightly larger then females. The abdomen and wings are
dark brown to black with individual gray hairs intermixed throughout
the fur (03). The mantle and sides of the neck are bright gold or
light brown. The color of the head varies from brown to to dark
brown. The teeth of P. m. mariannus are slightly heavier then those
of other subspecies (03). Anderson (03) provides other measurements
and morphological characteristics that distinguish this fruit bat.
Listed below are the taxonomic names and synonyms that have been used
to describe P. m. mariannus (03).
Pteropus mariannus, Desmarest, 1822, Mamm. 2., Suppl. p. 547
Taxonomy - 1 (DRAFT) - Taxonomy
Species BAT, FRUIT, MARIANA
Species Id ESIS051005
Date 14 MAR 96
Pteropus keraudren, Quoy and Gaimard, 1824, Voy. 'Uranie' Zool. pt.2,
p. 51, pl. 3. fig. 1 (animal), Fig. 2 (skull)
Pteropus keraudrenius, Temminck, 1825, Mon. Mamm. 1. p. 186, pl. 15.
Fig. 7 (skull, copy from Quoy and Gaimard)
Rousette keraudren, Quoy and Gaimard, 1825, Ann. Sci. Nat. 6:146
Pteropus keraudreni, Gray, 1838, Mag. Zool. and Bot. 2:503
Pteropus keraudrensis, Oken, 1838, Allg. Naturgesch. 7 Abth. 2:990
Pteropus marianus, Geibel, 1855, Saug. p. 998
Pteropus (Spectrum) mariannus, Matschie, 1899, Mergachir. p. 27,
pl. 5, Figs. 15,16 (skull)
Pteropus mariannus mariannus, Kuroda, 1938, L. M. Zool. Soc. Japan
p. 109.
Cotype specimens are present in the Paris and Leyden Museums
(03). In addition, at least 13 other specimens are reported from the
Paris Museum, seven specimens deposited in the American Museum of
Natural History, one specimen is reported at the Berlin Museum,
specimens are housed at the Division of Aquatic and Wildlife
Resources, Guam (03,04,02), and 1 whole mount, 2 skulls, and 2 skins
are in the collection at the Bishop Museum in Honalulu (31). An
unkown number of other specimens are probably held in other
collections.
The exact taxonomic status of Micronesian fruit bats, including
P. mariannus, is uncertain. Anderson (03) believed that a number of
species in the region were closely related, and referred to these as
members of the P. mariannus group. His system of maintaining these
taxa as separate species has been recently followed by Corbet and Hill
(05), and Nowak and Paradiso (06). However, other authorities believe
that the Micronesian members of this group are subspecies of
P. mariannus (07,04). They recognize the following subspecies:
P. m. mariannus, from the southern Mariana Islands; P. m. paganensis,
from the northern Mariana Islands; P. m. loochoensis, from the Ryukyu
Islands; P. m. pelewensis, from Palau; P. m. yapensis from yap; P. m.
ulthiensis from Ulithi Atoll near Yap; and P. m. ualanus from Kosrae.
The common name, Marianas fruit bat, is frequently used to
describe this bat. Most recent scientific articles use this name
(08,09,10,11). Marianne fruit bat is another variation of this name
(07). The ASC listing gives Mariana flying fox as another common
name. The IUCN Red List of Threatened Animals gives Marianas flying
fox as another common name variation. Fanihi is the local name for
fruit bats used by Chammorro residents throughout the Marianas.
Taxonomy - 2 (DRAFT) - Status
Species BAT, FRUIT, MARIANA
Species Id ESIS051005
Date 14 MAR 96
STATUS
Coded Status
E: Federal Endangered
Commercial
Commercial/consumption
Game (Consumptive Recreational)
Ceremonial/Cultural
COMMENTS ON STATUS -
U.S. STATUSES AND LAWS:
The Mariana fruit bat (Pteropus mariannus mariannus) been
designated an Endangered species pursuant to the Endangered Species
Act of 1973 (50 CFR 17.11; P.L. 93-205, 87 Stat. 884; 16 U.S.C.
1531-1540), as amended. Although the subspecies is found in Guam and
the southern islands of the Commonwealth of the Northern Marianas
Islands it is Federally listed only on Guam.
This subspecies is protected by the Lacey Act (P.L. 97-79, as
amended; 16 U.S.C. 3371 et seq.) which makes it unlawful to import,
export, transport, sell, receive, acquire, or purchase any wild
animal (alive or dead including parts, products, eggs, or offspring):
(1) in interstate or foreign commerce if taken, possessed,
transported or sold in violation of any State law or
regulation; or
(2) if taken or possessed in violation of any U.S. law,
treaty, or regulation or in violation of Indian tribal law.
It is also unlawful to possess any wild animal (alive or dead
including parts, products, eggs, and offspring) within the U.S.
territorial or special maritime jurisdiction (as defined in
18 U.S.C. 7) that is taken, possessed, transported, or sold in
violation of any State law or regulation, foreign law, or Indian
tribal law.
RESPONSIBLE FEDERAL AGENCIES:
USFWS -Responsible for the management/recovery, listing, and
law enforcement/protection of this species.
DOD -Responsible for the law enforcement/protection of this
species with applicable State and Federal laws on
public land under their control. Also responsible for
management/recovery on Department of Defense lands.
NPS -Responsible for the law enforcement/protection of this
species with applicable State and Federal laws on
public lands under their control. Also responsible
for conservation (Nat. Park System Organic Act - 16
U.S.C. 1, 2-3)/management/recovery on National Park
Service lands. Taking, possessing, or disturbing of
Status - 1 (DRAFT) - Status
Species BAT, FRUIT, MARIANA
Species Id ESIS051005
Date 14 MAR 96
Federally listed species is prohibited on NPS lands
(36 CFR 2.1, 2.2, and 2.3).
All Federal agencies have responsibility to ensure that any
action authorized, funded, or carried out by that agency is not likely
to jeopardize the continued existence of the species or result in the
destruction or adverse modification of Critical Habitat (50 CFR 402),
and to utilize their authorities to carry out programs for the
conservation of the species.
STATE STATUSES AND LAWS:
TERRITORY: Guam
DESIGNATED STATUS: Endangered
ADMINISTRATIVE AGENCY: (GU) Department of Agriculture,
Division of Aquatic and Wildlife
Resources
TERRITORIAL STATUTE: (GU) Endangered Species Act of Guam, 1981;
Guam Public Law 15-36, June 18, 1979.
COMMONWEALTH: Commonwealth of the Northern Mariana Islands
DESIGNATED STATUS: None
INTERNATIONAL STATUSES, TREATIES, AND AGREEMENTS:
In 1980, the species was proposed for listing by CITES, but
ultimately was never listed. However, the species is listed as
"vulnerable" by the IUNC Red List of Threatened Animals (1986).
ECONOMIC STATUSES:
If the enthusiasm of the Chamorro people for cooked fruit bat
is any indication of the animal's culinary value, then the Mariana
fruit bat should be ranked among the great gourmet delicacies of the
world. A major reduction in the population of these bats may have
occurred between 1920 and 1945 when extensive hunting took place
(12,13,10). Hunters report that fifty or more fruit bats can be
easily killed in a single successful raid on a roost. Fruit bats
are an important cultural food and served on special occasions such
as fiestas, weddings, christenings and holidays. People are willing
to pay high prices for the bats depending on special culinary
qualities such as unique taste and size. The bats are cooked and
eaten whole, including the fur. Bats are purchased on the black
market may bring 25 dollars per animal in Guam and Saipan (32).
The fruit bat was once an important seed dispersal vector of
large-seed trees.
79/05/18:44 FR 29128/29130 - Notice of review status
79/06/13:44 FR 33915/ - Extension of comment period
80/07/21:45 FR 48830/48845 - Notice of potential proposals to CITES
80/11/06:45 FR 73876/73881 - Notice of proposals to CITES
80/11/29:48 FR 53729/53733 - Proposed listing
84/08/27:49 FR 33881/33885 - Listing, final rule
85/09/18:50 FR 37958/37967 - Review of Vertebrate Wildlife
Status - 2 (DRAFT) - Status
Species BAT, FRUIT, MARIANA
Species Id ESIS051005
Date 14 MAR 96
87/01/21:52 FR 02239/02242 - Petition: List Endangered in N. Mariana
87/09/23:52 FR 35743/35748 - Proposed changes in CITES appendicies
87/12/28:52 FR 48820/48823 - Final rule; added to CITES-II
Status - 3 HABITAT ASSOCIATIONS
HABITAT - TERRESTRIAL
TERRESTRIAL
LAND USE -
Evergreen Forest Land
Forested Wetland
NATIONAL WETLAND INVENTORY CODES
NWI NWICLS NWIMOD NWISPEC
Palustrine FO3
COMMENTS ON HABITAT ASSOCIATIONS -
Nine vegetative types have been described for Guam (19,20) with
four of these used regularly by Mariana fruit bats (10). In
northern Guam, where these animals are most common, bats forage and
roost mainly in native limestone forest (08,10). Mature limestone
forest is characterized by sparse undergrowth, a canopy 8 to 15 m
high and scattered taller emergent trees. Common species include
Ficus prolixa, Aglaia mariannensis, Guamia mariannae, Cycas
circinalis, Neisosperma oppositifolia, Mammea odorata, Macaranga
thompsonii, Pisonia grandis, Artocarpus mariannensis, Eleaocarpus
joga, and Triphasia trifolia. Secondary growth limestone
forest is shorter and has dense undergrowth. Many of the same
species are present in lower abundance as well as Pandanus
tectorius, P. dubius, Hibiscus tiliaceus, Morinda citrifolia, Carica
papaya and Cestrum diurnum. Large stands of this forest type occur
in northern Guam, especially along clifflines. Soils in these areas
tend to be thin and rocky. Limestone rock outcrops are a common
feature.
Wiles (27,28,29) described the characteristics of six roosts
used by colonies of Mariana fruit bats. These sites occurred in
limestone forest and were found along or within 100 m of the large 80
to 180-m-tall cliffline that fringes northern Guam. Bats preferred
to roost in mature fig trees (Ficus prolixa) at five colonies and in
chopak (Mammea odorata) at a six location. Other roosting trees
included gagu (Casuarina equisetfolia), pengua (Macaranga
thompsonii), panao (Guettarda speciosa), and fagot (Neisosperma
oppositifolia). Gagu and Ficus are commonly used for roosting by
solitary animals and small groups of two to 15 bats (08).
Coconut groves and strand vegetation are other plant communities
used occasionally by bats for feeding and roosting (10). Coconut
(Cocos nucifera) groves exist throughout the island with large stands
present from Tarague Point to Uruno Point and on the Naval Magazine.
This tree species commonly ranges from 10 to 20 m in height. A
thick understory composed commonly of Triphasia trifollia, Guamia
mariannae, Aglaia mariannensis and Neisosperma oppositifolia is often
present. Strand vegetation exists along rocky and sandy shorelines
where halophytic conditions exist. Heights of vegetation range from
short ground cover to trees up to 20 m tall. Cocos nucifera,
Casuarina equisetifolia, Pemphis acidula, Scaevola sericea,
Tournefortia argentea and Hernandia sonora characterize this habitat.
In southern Guam, a few fruit bats still inhabit ravine forests
(10). This type of forest grows on volcanic soils. It is lower in
height and more brushy than limestone forest and frequently contains
Hibiscus tiliaceus, Pandanus tectorius, Areca cathecu, Ficus prolixa,
Cycas circinmalis, Cocos nucifera and Freycinetia torresiana. Low-
Habitat Associations - 1 lying portions of this forest may flood seasonally. These areas are
designated in the National Wetlands Inventory as palustrine,
forested, broad-leaved evergreen (P0F03).
Farms, savannas and mangroves (NWI designation: E2SS3) are
other habitats that receive little or no use at present but may have
been used commonly in the past when bats were more abundant and
widespread on the island. Residents often tell of fruit bats
formerly entering farms to feed in cultivated fruit trees. Because
known fruit bat foods occur throughout the island in a variety of
habitats, it is likely that in the past, fruit bats also occurred
islandwide.
Habitat use of Mariana fruit bats on the islands from Rota to
Saipan is probably similiar to that on Guam. However, there are no
ravine forests on these islands (10).
There does not appear to be any seasonal changes in habitat use
by Mariana fruit bats (10).
Habitat Associations - 2 (DRAFT) - Food Habits
Species BAT, FRUIT, MARIANA
Species Id ESIS051005
Date 14 MAR 96
FOOD HABITS
TROPHIC LEVEL -
HERBIVORE
LIFESTAGE FOOD FOOD PART
General Evergreen Shrubs-Flowers/Fruit/Seed
General Coniferae
General Evergreen Trees-Flowers/Fruit/Seed
Food Habits - 1 (DRAFT) - Environment Associations
Species BAT, FRUIT, MARIANA
Species Id ESIS051005
Date 14 MAR 96
ENVIRONMENTAL ASSOCIATIONS
G = General A = Adult
LIM = Limiting RA = Resting Adult
J = Juvenile FA = Feeding Adult
RJ = Resting Juvenile BA = Breeding Adult
FJ = Feeding Juvenile P = Pupae
L = Larvae E = Egg
RL = Resting Larvae
FL = Feeding Larvae
LIFESTAGE ENVIRONMENTAL ASSOCIATIONS
G Coastal Features: Vegetated offshore islands
G Terrestrial Features: Cliffs/ledges
Environment Associations - 1 (DRAFT) - Life History
Species BAT, FRUIT, MARIANA
Species Id ESIS051005
Date 14 MAR 96
LIFE HISTORY
FOOD HABITS:
Twenty-two species of plants are known to be used by fruit bats
in the Marianas. This includes fruit of 17 species, flowers of 7
species and the leaf of one species. It appears that favored foods
include the fruits of breadfruit (Artocarpus mariannensis and A.
altilis), and papaya (Carica papaya), fadang (Cycas circinalis), figs
(Ficus spp.), kafu (Pandanus tectorius), and talisai (Terminalia
catappa) and the flowers of kapok (Ceiba pentandra), coconut (Cocos
nucifera) and gaogao (Erythrina variegata). The stems of leaves and
tips of small twigs on A. mariannensis are also often eaten. Other
foods include the fruit of Annona reticulata, Cynometra ramiflora,
Elaeocarpus joga, Hernandia sonora, Mangifera indica, Musa spp.,
Neisosperma oppositifolia, Ochrosia mariannensis, Psidium
guajava, and Tristiropsis acutangula and the flowers of Dendrocnide
latifolia, Elaeocarpus joga and Terminalia catappa.
Most favored foods are available throughout the year and there
appears to be little seasonality in their use (10). Exceptions are
the fruits of Artocarpus which are ripe from April to December and
the flowers of Ceiba pentandra and Erythrina variegata which are
present from January to March.
HOME RANGE/TERRITORY:
Little is known about the nightly movements and behavior of
Marianas fruit bats. Occasional sightings of bats at night indicate
that animals in northern Guam may disperse throughout the forested
areas of Anderson Air Force Base and Naval Communications Area Master
Station to feed (02). When colonies are located on Pati Point, bats
may travel as far as 10 to 12 km to reach feeding sites on the
island's northwest coast.
During the day, most Mariana fruit bats are highly colonial and
may roost in aggregations of up to 850 animals (02). A small portion
of Guam's population, about 5 to 10%, roost solitarily or in small
groups of 2 to 12 animals (02). Within larger colonies, some males
form harems in which they defend females for breeding purposes (26).
Harems usually encompass a single set of branches in the crown of a
roost tree and may range in size up to 4 m long and several meters
wide and tall.
PERIODICITY:
Animals in colonies sleep during much of the day but engage in
other activities as well (02). These include: grooming; breeding;
scent rubbing and marking; flying; climbing to other roost spots;
and defending roosting territories (harem males only) (02). Bats
gradually depart colonies for several hours after sunset to forage
(02). Perez (01) observed that bats returned to a colony on Orote
Point until 8:00 a.m., however, at roosts at Jinapsan Point and Pati
Point from 1981 to 1985, Wiles (02) found that almost all animals
arrived before dawn. Wheeler and Aguon (08) reported that solitary
bats tended to be more mobile during the day. They observed flying
bats most frequently from 5:00 to 9:00 a.m..
Life History - 1 (DRAFT) - Life History
Species BAT, FRUIT, MARIANA
Species Id ESIS051005
Date 14 MAR 96
MIGRATION PATTERNS:
Mariana fruit bats are not known to be migratory; however,
occasional colony-sized movements between islands are believed to
occur (10). In the past, when fruit bats were abundant, these
movements may have been more frequent and related to food scarcity.
At present, flights of this type are rare. Any flights of this nature
may be caused by human disturbance of roosts. Two colony-sized
movements from Rota to Guam apparently occurred in 1980, a distance
of 60 km (10).
COVER/SHELTER REQUIREMENTS:
Wiles (27,28,29) described the characteristics of six roosts
used by colonies of Mariana fruit bats. These sites occurred in
limestone forest and were found along or within 100 m of the large 80
to 180-m-tall cliffline that fringes northern Guam. Bats preferred
to roost in mature fig trees (Ficus prolixa) at five colonies and in
chopak (Mammea odorata) at a six location. Other roosting trees
included gagu (Casuarina equisetfolias), pengua (Macaranga
thompsonii), panao (Guettarda speciosa), and fagot (Neisosperma
oppositifolia). Gagu and Ficus are commonly used for roosting by
solitary animals and small groups of two to 15 bats (08).
Mature Ficus posssess large open crowns which probably allow
bats to take-off and land more easily (28). This tree's large crown
may also facilitate harem formation (28).
REPRODUCTIVE SITE REQUIREMENTS:
Reproductive activities (courting, breeding, parturition,
raising of young) of fruit bats usually take place in harems at
colonies but may also occur at night while bats forage (02). Colony
sites are described under Cover/Shelter Requirements. Young fruit
bats are taken on nightly feeding expeditions by their mothers until
the young become too large to be carried.
REPRODUCTIVE CHARACTERISTICS:
Many reproductive characteristics are poorly uderstood for
Mariana fruit bats. These bats maintain a consistent social
organization throughout the year (02). During the day, within larger
colonies, about 69% to 80% of all individuals roost in harems which
contain a single male and two to 15 females (26,02). Harem males are
highly territorial and maintain exclusive breeding rights with these
females (26). Harem males only rarely tolerate the presence of
another male. Females appear to be loosely bound to a particular
harem (26). Colonies may also contain one or two groups of bachelor
males that roost in nearby trees (26,02). These groups may number
from 10 to 120 animals (26,02) A few soliatry males, comprising
3% to 8% of the entire colony, roost on the periphery of colonies
(26). Bachelor fruit bats have been observed occasionally to form
separate smaller colonies with 10 to 125 animals (30).
Mating and presence of nursing young among Mariana fruit bats
has been observed throughout the year on Guam (01,02). There does
not appear to be a seasonal peak in birth of young. Females give
birth to a single young (02). The length of pregnancy and age of
sexual maturity is not known. Other species of Pteropus have a
Life History - 2 (DRAFT) - Life History
Species BAT, FRUIT, MARIANA
Species Id ESIS051005
Date 14 MAR 96
gestaion period of 4 1/2 to 6 months (03,31,32). Sexual maturity
is probably reached by females at 6 to 18 months of age (02), rather
than at 3 years as previously stated by Wheeler and Aguon (08).
PARENTAL CARE:
The ages at which young Mariana fruit bats reach certain stages
of development are poorly known. Baby fruit bats are altricial when
born. Mothers carry their young throughout the day while roosting
and at night while foraging (02). Young bats attach themselves to
their mother's chest and to one of her enlarged nipples located on
side of her abdomen. At a certain size, juvenile fruit bats become
to large to be carried by their mothers and are left at the colony
roost at night while the mothers feed. Parents return during the day
to nurse the young animals. The ages at which bats are able to first
fly and are weaned are not known.
POPULATION BIOLOGY:
Illegal hunting and possibly predation by brown tree snakes
(Boiga irregularis), an introduced animal, are the current limiting
factors of Mariana fruit bats (10). Food resources and potential
roosting sites seem to be adequately available and not limiting the
population on Guam (02).
At a colony on Guam, the overall sex ratio of adult bats was
37.5 males to 100 females in 1982 (m=700) and 72.7 males to 100
females in 1984 (m=475) (02,26). The longevity of these fruit bats
is not known. Other species of Pteropus are considered to be long
lived (06).
The recovery potential of this bat appears to be high. A sex
ratio skewed strongly toward females and the probable ability of
females to produce young annually indicate that the Guam population
of P. m. mariannus is capable of doubling in size over two to three
years.
SPECIES INTERRELATIONSHIPS:
The potential effect of predation by brown tree snakes (Boiga
irregularis) on Mariana fruit bats has been discussed the field
"N-REASON". The exact nature of the present relationship between
these two species has not been determined.
Ficus prolixa is highly preferred as a roosting tree by colonies
of P. m. mariannus (27,28,29). Loss of this tree species to disease
or insect damage could alter the roosting patterns or social
organization of these bats.
OTHER LIFE HISTORY DESCRIPTIORS:
None.
Life History - 3 (DRAFT) - Management Practices
Species BAT, FRUIT, MARIANA
Species Id ESIS051005
Date 14 MAR 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Adverse
Adverse
Adverse Commercial Exploitation
Adverse Exotic/Feral/Introducted Species
Adverse Forest Alteration
Adverse Harvesting
Adverse Poaching
Adverse Predation
Adverse Vegetation Composition Changes
Beneficial Stocking captive-reared wild-strain animals
Beneficial Controlling/Removing Exotic Vertebrates
Beneficial Maintaining undisturbed/undeveloped areas
Beneficial Controlling/Restricting Noncommercial Harvest
Beneficial Reforestation
Beneficial Transplanting wild animals
Beneficial Controlling/Removing Domestic Animals
Beneficial Regulating commercial harvest levels
Beneficial Land Acquisition
Beneficial Maintaining Later Stages of Succession
Beneficial Restricting Poaching
Existing
Existing
Existing Commercial Exploitation
Existing Exotic/Feral/Introducted Species
Existing Forest Alteration
Existing Harvesting
Existing Poaching
Existing Predation
Existing Vegetation Composition Changes
COMMENTS ON MANAGEMENT PRACTICES -
Overhunting and poaching have been the most important causes
in the decline of the Mariana fruit bat (P. m. mariannus) (10). A
major reduction in the population of these bats may have occurred
between 1920 and 1945 when extensive hunting took place (12,13,10).
Although difficult to quantify, illegal hunting of fruit bats has
continued since 1966, when bats where first granted partial legal
protection. From 1981 to 1984, eight cases of hunting at colonies
and seven cases of night hunting along flyways or at feeding sites
are known (10). More unrecorded incidents undoubtedly occurred.
Colony hunting is the most destructive form of fruit bat hunting
because animals in colonies typically roost close together in large
numbers, and thus are highly vulnerable to shotgun fire. Hunters
report that fifty or more fruit bats can be easily killed in a single
successful raid on a roost.
Forest destruction has probably been a minor factor in the
decline of Pteropus on Guam (10). Large stands of native forest
have been cleared for agriculture and housing in the central and
Management Practices - 1 (DRAFT) - Management Practices
Species BAT, FRUIT, MARIANA
Species Id ESIS051005
Date 14 MAR 96
north-central portions of the island. Sizeable tracts of forest were
also destroyed during the invasion and bombardment of Guam in World
War II and by subsequent construction activities on newly established
American military bases. However, fruit bats were already considered
uncommon by 1945 (13,14). Sizable tracts of forest remained after the
war and are still present today, yet few bats inhabit these forest
lands. Food resources and potential roosting sites seem to be
adequately available and not limiting the population of P. m.
mariannus (15).
The impact of predation by brown tree snakes (Boiga
irregularis) on fruit bats is unknown but potentially serious (10).
These snakes were first introduced to Guam after World War II. They
seem capable of at least preying upon young bats. Stomach contents
of large snakes routinely contain adult roof rats (Rattus rattus)
(16) which are similar in size to juvenile P. m. mariannus. One case
of snake predation on bats has been reported by a local resident
(10). Other evidence, although circumstantial, suggests that snakes
may be preying on young Marianas fruit bats at roosts. Large-sized
juveniles may be vulnerable to predation because they are not yet
able to fly and are too large to be carried by their mothers during
night time foraging. Thus, they are left overnight at the roosting
site where they may be susceptible to nocturnal predators.
Typhoons are a rare but potentially serious threat to Guam's
small number of remaining P. m. mariannus (10). Strong typhoons
with sustained winds of more then 250 kph strike the island about
every 10 to 15 years. Although there is no evidence that storms have
ever greatly reduced fruit bat numbers on Guam in the past (probably
due to the lack of serious observations), severe typhoons have been
implicated in precipitous declines of Pteropus on several islands in
the western Indian Ocean (17). Gale-force winds on Guam are capable
of denuding large forested areas of foliage and fruit (18) and
residents have reported finding dead bats under roosting trees after
strong storms. Animals not killed directly by winds could face a
period of up to several months of low food supplies.
UNAPPROVED PLAN:
U.S. Fish and Wildlife Service. 1987. Recovery Plan for the
Marianas Fruit Bat and Little Marianas Fruit Bat on Guam.
Technical Draft. U.S.Fish and Wildlife Service, Portland, OR.
107 pp.
Excessive hunting and other disturbance by humans has led to
the precipitious decline of the fruit bats throughout the populous
islands of the Marianas. The recovery plan for the Mariana fruit bat
states as its primary objective to "increase the population of the
Mariana fruit bats on Guam through natural recruitment to a minimum
of 2,500 animals, and to establish a minimum of two permanent bat
colonies in northern Guam and a single permanent colony in southern
Guam." This population could be considered for reclassification
to threatened status once these goals are met. Planned recovery
actions include: (1) control of illegal hunting of fruit bats (both
for commercial and subsistence purposes) through law enforcement;
Management Practices - 2 (DRAFT) - Management Practices
Species BAT, FRUIT, MARIANA
Species Id ESIS051005
Date 14 MAR 96
(2) preventing predation by the exotic Brown Tree Snake (if, indeed,
this is a problem) first through research, then through application
of control measures; (3) determining the effects of trade in fruit
bats on Guam's fruit bat population; (4) continuing research on
autecology of fruit bats; (5) legally securing and protecting
essential forest ecosystems; (6) managing essential forest
ecosystems for the benefit of the fruit bat by limiting human
disturbance (development) and limiting forest clearing (maintaining
later succesional stages) and by determining the impact of alien
plants and animals (livestock and exotic) on fruit bat habitat;
(7) monitoring the status of fruit bats on Guam; (8) promoting
conservation of fruit bats in the northern Marianas and developing
a regional program for managing fruit bats; (9) developing a public
awareness program; (10) if necessary augmenting existing populations
of fruit bats on Guam through captive breeding and/or transplanting
wild individuals.
Recovery actions completed or ongoing include: (1) ongoing
autecological studies and censuses; (2) ongoing law enforcement;
(3) designated conservation reserves on 1700 ha of territorial land
and on ca. 500 ha of Air Force and Navy lands; (4) ongoing research
on the Brown Tree Snake; and (5) a public information program, now
discontinued.
Management Practices - 3 (DRAFT) - References
Species BAT, FRUIT, MARIANA
Species Id ESIS051005
Date 14 MAR 96
References
***** REFERENCES FOR ALL NARRATIVES EXCEPT N-OCCURENCE *****
01 Perez, G.S.A. 1972. Observations of Guam bats. Micronesica
8:141-149.
02 Wiles, G.J. Unpubl. data. Division of Aquatic and Wildlife
Res., Dept. of Agric., P.O. Box 2950, Agana, Guam 96910.
03 Anderson, K. 1912. Catalogue of Chiroptera in the collection of
the British Museum. Volume 1: Megachiroptera. British Museum
(Nat. Hist.), London. 854 pp.
04 Koopman, K.F. 1984. Pers. comm. Am. Mus. of Nat. Hist., New
York, NY 10024. October 24, 1984.
05 Corbet, G.B. and J.E. Hill. 1980. A world list of mammalian
species. British Museum (Natural History), London. 226 pp.
06 Nowak, R.M. and J.L. Paridiso. 1983 Walker's mammals of the
world. 4th ed., 2 vol. John Hopkins Univ. Press, Baltimore.
1362 pp.
07 Kuroda, N. 1938. A list of Japanese mammals. L.M. Zool. Soc.
Japan, Tokyo.
08 Wheeler, M.E. and C.F. Aguon. 1978. The current status and
distribution of the Mariannus fruit bat of Guam. Aquatic and
Wild. Resources Div. Tech. Rep. No. 1. 29 pp.
09 Wheeler, M.E. 1980. The status of the Marianas fruit bat on
Saipan, Tinian and Rota. 'Elepaio 40:109-113.
10 Wiles, G.J. In prep. The status of fruit bats in Guam.
Division of Aquatic and Wildlife Resources, Agana, Guam.
11 Payne, N.H., T.O. Lemke and G.J. Wiles. In prep. Fruit bat
populations in the northern Marianna Islands, western Pacific.
Division of Aquatic and Wildlife Resources, Agana, Guam.
12 Crampton, H.E. 1921. A journey to the Mariana Islands - Guam
and Saipan. L. Amer. Mus. Nat. Hist. 21:127-145.
13 Baker, R.H. 1948. Comments on conservation problems in
Micronesia. Pages 53-55 in Coolidge, H.J. (ed.). Conservation in
Micronesia. Research Council, Washington, D.C. 70 pp.
14 Baker, R.H. Personal communication. 302 N. Strickland St., Eagle
Lake, TX 77434. May 12,1981.
15 Savidge, J.A. Personal communication. Division of Aquatic and
Wildl. Resources, Dept. Agriculture, P.O. Box 2950, Agana, Guam
96910. December 10, 1985.
16 Cheke, A.S. and J.F. Dahl. 1981. The status of bats on western
Indian Ocean islands, with special reference to Pteropus.
Mammalia 45:205-238.
17 Kami, H.T., N. Drahos, R.D. Strong, and R.J. Lujan. 1976. Study
of the fruit bat. Pages 72-75 In: Guam Aquatic and Wildlife
Resources Division Annual Report, FY 1976. Dept. of Agriculture,
Guam.
18 Fosberg, F.R. 1960. The vegetation of Micronesia. Bull. Amer.
Mus. Nat. Hist. 119:1-75.
19 Stone, B.C. 1970. The flora of Guam. Micronesica 6:1-659.
20 Wiles, G.J. 1983. The current status, distribution and natural
history of Marianas fruit bats. In: Guam Aquatic and Wildlife
Resources Division Annual Reports, FY 1981. Department of
References - 1 (DRAFT) - References
Species BAT, FRUIT, MARIANA
Species Id ESIS051005
Date 14 MAR 96
Agriculture, Guam.
21 Stafford, W.E. 1905. The useful plants of Guam. Contrib. U.S.
Natl. Herb. 9:1-416.
22 Stafford, W.E. 1910. A year on the island of Guam, extracts from
the notebook of a naturalist on the island of Guam. I-XXV.
Micronesian Area Research Center, Univ. Guam, Mangilao. Unpubl.
254. pp.
23 Linsley, L.N. 1934. Curious things about Guam. The faniji.
Guam Recorder 11:194-195.
24 Wheeler, M.E. 1979. Study of the fruit bat. Pages 230-260 In:
Guam Aquatic and Wildlife Resources Division Annual Report,
FY 1979. Department of Agriculture, Guam.
25 Wiles, G.J. 1982. The current status, distribution and natural
history of Marianas fruit bats. In: Guam Aquatic and Wildl.
Resources Div. Annual Reports, FY 1982, Dept. of Agriculture,
Guam.
26 Wiles, G.J. 1981. Movement patterns and habitat utilization of
Mariana fruit bats. in Guam Aquatic and Wildlife Resources
Division Annual Reports, FY 1981. Dept. of Agriculture, Guam.
27 Wiles, G.J. 1982. Movement patterns and habitat utilization of
Mariana fruit bats. In: Guam Aquatic and Wildlife Resources
Division Annual Reports, FY 1982. Dept. of Agriculture, Guam.
28 Wiles, G.J. 1983. Movement patterns and habitat utilization of
Mariana fruit bats. In: Guam Aquatic and Wildlife Resources
Division Annual Reports, FY 1983. Dept. of Agriculture, Guam.
29 Baker, J.R. and Z. Baker. 1936. The seasons of a tropical rain
forest (New hebrides). Part 3. Fruit bats (Pteropidae). J.
Linn. Soc., London 40:123-141.
30 Gopalakrishna, A. 1969. Gestation period in some Indian bats.
J. Bombay Nat. Hist. Soc. 66:317-322.
31 Allison, Allan. 1987. Pers. comm. Bishop Mus., Honolulu, HI.
32 U.S. Fish and Wildlife Service. 1987. Memo to CITES Secretariant
on: Proposals to ammend Appendices I and II. U.S. Fish and Wildl.
Serv. (FWS/OSA) Feb. 11, 1987. Memo + attachment.
***** REFERENCES FOR N-OCCURRENCE NARRATIVE ONLY *****
01 Kuroda, N. 1938. A list of Japanese mammals. L.M. Zool. Soc.
Japan, Tokyo.
02 Wheeler, M.E. 1980. The status of the Marianas fruit bat on
Saipan, Tinian and Rota. 'Elepaio 40:109-113.
03 Payne, N.H., T.O. Lemke and G.J. Wiles. In prep. Fruit bat
populations in the northern Mariana Islands, western Pacific.
04 Yamashina, Y. 1932. New subspecies of bats from the mandated
south Pacific islands. Trans. Nat. Hist. Soc. Formosa 22(121):
240-241 (In Japanese).
05 U.S. Fish and Wildlife Service. 1984. Endangered and threatened
wildlife and plants: determination of endangered status for seven
birds and two bats of Guam and the Northern Mariana Islands.
Fed. Register 49:33881-33885. August 27, 1984.
06 Wiles, G.J. In prep. The status of fruit bats in Guam.
07 Wiles, G.J. Unpublished data. Division of Aquatic and Wildlife
References - 2 (DRAFT) - References
Species BAT, FRUIT, MARIANA
Species Id ESIS051005
Date 14 MAR 96
Resources, Dept. of Agriculture, P.O. Box 2950, Agana, Guam
96910.
08 Lemke, T.O. 1984. Marianas fruit bat surveys and inventories.
Pages 3-16 in Annual Rept. Pittman-Robertson Federial Aid in
Wildlife Restoration Program, FY 1984. CNMI Division Fish and
Wildl., Saipan. 137 pp.
09 Wiles, G.J., R.E. Beck, Jr. and A.B. Amerson, Jr. in prep.
Mammals of Tinian.
References - 3