Innocent
mongoose

Guilty persons who introduce alien species

The Small Indian Mongooses are considered harmful animals which give damages the ecosystem
on Amami Oshima, however, the mongooses are important species in the original habitat in India.
We have to recognize the ecosystem damages caused by the introduction of invasive alien species,and not repeat again same mistakes in future.

Three principles in prevention of damages caused by alien species
No Introduction

No Release

No Spreading

No Introduction of alien
species which havea possibility to cause
damages to ecosystems

No Release of alien
species into the field

No Spreading of alien
species which alreadyexist in specific areas toother areas

Revised

2 019

Existing alien species on Amami-Oshima Island

Many alien species are recognized on the Island, such as feral cats, goats, the Black Rat, and theLanceleaf Tickseed, in addition to the mongooses. Effective measures are necessary for control ofthese alien species which give directly and indirectly damages on ecosystems on the Island.

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ecosystem in Amagoose on Amami-Oshima IslandCll Indian Mon
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Feral catFeral goat

Black Rat

Lanceleaf Tickseed

Small Indian Mongoose, an invasive alien species

The mongooses are listed in invasive alien species by the Invasive Alien Species Act, and it is prohibited to keep and transport of live animals. AMB catch the mongooses with special permission.
Alien species acts

Conservation of the nature on Amami-Oshima Island
Don't abandon
pets

Once the predatory pets are abandoned in wild, they act like the mongooses and attack the precious
animals on Amami Oshima. The stray pets have risks of road kill and infection animal disease. It is
important for your pet’s well-being to keep the pets inside following animal welfare rules.

Pet Cat Ordinance of 5 local governments on Amami-Oshima Island
To insert microtips, and attach neck rigs and register domestic cat kept
To keep cats inside door
● To castrate cats except cats complete keeping inside● To keep maximum 4 cats, you need special permission to keep more than 5 cats
● Not to give unnecessarily foods to cats of other people/ stray cats●●

the regulation of
pet cat and its
management

January 2020
Published by:
Okinawa Amami Nature Conservation Office, the Ministry of Environment
Amami Wildlife Conservation Center☆ We ask for your cooperation inactivity ofAmami Mongoose Busters

FOR ALL THE LIFE ON EARTH
Biodiversity

Edited by : Japan Wildlife Research Center
Design :artpost inc.
Photos :Mamoru Tsuneda, Teruho Abe, Yoshihito Goto, Kazuki Yamamuro,
Ryuta Yoshihara, Japan Wildlife Research Center

Blog：
https://amb.amamin.jp

facebook：
https://www.facebook.com/
amamimongoosebusters/

A m a m i Oshima

Habu Viper
Protobothrops flavoviridis

Animals and plants
in Amami-Oshima Island

The Habu Viper is a large size poisonous snake more than 2 m length. The snakes inhabit on Amami Oshima, Tokunoshima, Okinawa Islands, and other several neighboringsmall Islands. The Island’s people have always a mortal fear of the snake. The snake isthe top predator in the food chain of forest ecosystem on the Island, and prey on various
animals such as rats, birds, lizards, and frogs.

Owston's White-backed Woodpecker

Amami Oshima is located in subtropical zone, and the island supports
one of the largest laurel forests in Japan. Rich and diverse natural environments remain on the island which is surrounded by a beautiful oceanwith coral reefs. The unique biodiversity of the Amami Oshima has developed because the island has been isolated from outside the areas formillions of years. As a reflection of its distinctive natural environmental
history, many globally precious and endemic species such as the Amami

Ryukyu Ayu-fish

Rabbit evolved in the island. Many of ancestors of the native species mi-

Plecoglossus altivelis ryukyuensis

grated to Amami Oshima long years ago, when the island was connected

An endemic freshwater fish to Amami Oshima andOkinawa Island. The fish became extinct on Okinawa Island, and was reintroduced into the islandfrom Amami Oshima.

to the Eurasian Continent. We must preserve the rich and diverse naturalenvironment of Amami Oshima for future generations.

Amami Rabbit
Pentalagus furnessi

Amami Calanthe

This primitive rabbit is found only on Amami Oshima
and Tokunoshima. The Amami Rabbit stays in burrows
in daytime, and leaves there at night to eat seedlings
and acorns.

Calanthe amamiana
An orchid group plant, endemic to Amami Oshima. The plants bloom
with beautiful pink and white flowers on March and April. The orchid iscommon on the Island, but population size of the plant has decreased
due to overexploitation and deforestation

Ryukyu Long-haired Rat
Diplothrix legata
The largest rat in Japan, and endemic to Amami
Oshima, Tokunoshima, and the northern part of
Okinawa Island. It is arboreal, and mainly eats
nuts and others on the trees.
Kakeromajima
Tokunoshima

Amami Oshima

Ukejima

The northern part of Okinawa Island

AmamiOshimaIslandNominated to the world heritage site:
Amami-Oshima Island, TokunoshimaIsland, the northern part of Okinawa
Island, and Iriomote Island

Area：712㎢
Highest elevation：
Amami Ishikawa’s Frog
694m（Mt. Yuwan-dake）
Odorrana splendida
Population：
About 61,200 people
A frog species of beautiful green color
with gold spots. This frog is found only
on Amami Oshima. Its call echoes
throughout the mountain streams atnight in breeding season.

Amami Spiny Rat

A species ofLongicorn Beetle

Tokudaia osimensis
Endemic species to Amami Oshima. The Amami Spiny
Rats lack the Y chromosome (viz. XO-type sex chromosome) as same as the Tokunoshima Spiny Rats, a closely-related species of the rat. The rats are covered byspine-like hairs, and dodge attacks of the Habu Vipers.

Rosalia ferriei

Amami Jay
Garrulus lidthi
A beautiful bird with bright blue and brown in color. It is
endemic to Amami Oshima, Kakeromajima, and Ukejima. It forages nuts and buries them.

2

A long-horned beetle, endemic to
Amami Oshima. Adults appear
short period in summer. The beetle
prefers old trees of such as chinquapins (Castanopsis sieboldii ), anddecrease of population size is concerned due to deforestation.

HELLO
I am AMAKUROThe Government of Japan has submitted thenomination documents of Amami-Oshima Island,
Tokunoshima Island, the northern part of Okinawa
Island, and Iriomote Island for the World Heritage
Site to the UNESCO World Heritage Center in2017 and in February 2019.
Amami Oshima contains rich nature environment
in evergreen broadleaf forests under semi tropicalclimate, and many endemic species which wereformed through the geography feature of the island, separation and joint from/ with the EurasianContinental. The Japanese Government aims toprotect the only one biodiversity on the Amami
Oshima through listing the Islands to the World
Heritage.
The eradication of the Small Indian Mongoose on
Amami Oshima is an essential effort for the conservation of the biodiversity on the Island, and an
important project for listing the area to the World
Heritage.

3

Why and when did the mongooses introduced to Japan?

Biology of the Small Indian
Mongoose
The Small Indian Mongooses were introduced and released into
Amami Oshima in 1979 for control of Habu Vipers and rats. Mongooses have become invasive animal species and give damage
to ecosystems throughout the world. In Japan, all mongoose
species of Herpestidae family were designated as invasive alien
species under the Invasive Alien Species Act in 2005.

Definition of invasive alien species
in Alien Species Act
Individuals and their organs, stipulated under theInvasive Alien Species Act, have been brought toJapan from overseas and cause harm to ecosystems,
people's lives, and the farming industry. Breeding,transporting, importing, and releasing of the invasive
alien species are prohibited by the Act.

Ecology of the Small Indian Mongoose

Herpestes auropunctatus ※A Habu Viper attacks a Black Rat. Despite
the introduction of mongooses, no significant decrease of the Habu Viper population
has been observed in Amami Oshima.

Body size

Food

Body length Males : 60 cm
Females : 50 cm
WeightMales : 600 to 1,000 g
Females : 400 to 600 g

Distribution

The people of Amami Oshima and Okinawa Island have sufferedfrom bitten damage by the poisonous Habu Viper. In 1910, Dr. Shozaburo Watase, a zoologist of Tokyo University, released mongooses in
Okinawa Island in the hope that they would decrease the populationof Habu Vipers and Black Rats (on which Habu Vipers prey). This effort, however, brought very little effect on decrease of the Habu Viper and rat populations. Nevertheless, mongooses were released on
Amami Oshima in 1979.

Insects, lizards, and rats are most important prey of mongooses.
In addition, birds and small mammals are also predated by the
animals.

The Small Indian Mongoose (Herpestes auropunctatus ) originally ranges
from the Middle East to China. They were also released on the Hawaiian
and Caribbean islands and have established populations in these islands.
In Japan, it has been confirmed that the mongooses inhabit on Amami
Oshima, Okinawa Island, and in parts of Kagoshima City.

Ecology
Reproduction：
Mongooses give birth once or twice a year in warm season, from
April to September in Amami Oshima. Litter size is 1 to 5 (an average of 2.26). The young reach adult size in about 8 months after
birth.

Life span：
On Amami Oshima, the average life span of mongooses is 1 to 2
years and the maximum life span is about 3 to 4 years.

Males 60cm, Females 50cm

Home range size：
The home range size of mongooses is 20 ha for adult males and
24 ha for females. They sometimes travel more than 2 km over ashort period of time.

※ Although the mongooses introduced to Amami Oshima were considered Javan mongooses (Herpestes javanicus), recent studies haveshown that they are actually Small Indian Mongooses(H. auropunctatus)(Urva auropunctatus, as an alternative taxonomy).

Introduction of the Small
Indian Mongooses to Japan.
Okinawa to
Amami
From theGanges river

1910

1979

Introduction of the mongooses degraded the forest
ecosystem of Amami-Oshima Island
I visited Amami Oshima for the first time in 1987, during my last summer vacation in college. I stayed for about a

The mongooses occur now in Japan were caught in theweek, and I visited various places of the mountain and ocean areas in Amami Oshima and Kakeromajima. I was

estuarine area of the Ganges River and introduced tofascinated by Amami Rabbits and Amami Woodcocks that appeared one after another along the forest trails of

Okinawa Island in 1910, and then brought to Amami

Kinsakubaru at night trekking. I started living on Amami Oshima in the following spring after I graduated from

Oshima from Okinawa Island in 1979.

college. I regularly visited the forest trails in Setouchi Town and Sumiyo Town, Amami City,

A number of the Small Indian Mongoose still inhabit

where I encountered many Amami Spiny Rats as well as Amami Rabbits running along theon the Okinawa Island. Ministry of the Environment,

trails. When I went to Kinsakubaru on a winter day with Mr. Takeichiro Minami, a Habu Viper

Japan(MOEJ) and local governments conducts eradica-catch specialist, a marvelous sound like birds chirping echoed through the forest trails attion project of the mongoose in Yambaru area, north-night. Mr. Minami told me that the animal sound is chorus of Amami Ishikawa’s Frogs. It was
like a large choir, and it sounded like there were hundreds of frogs calling. I never expected

ern part of the Island and habitats of Okinawa rail andother important species, for conservation of the ecosystems on the Island.

4

Yukari Handa（Mammalogical Society ofAmami）and I investigating mongooses in 1990

that the animals in Kinsakubaru would disappear in a matter of a few years. The establishment and increase in the number of mongooses drastically have affected status of otheranimals in the forest.

Shintaro Abe (Ministry of the Environment, Japan)
5What is caused by the Small

Indian Mongoose ?

Amami Woodcock

Problem

1

Green Grass Lizard

Introduction of the mongooses
Mongooses were brought into Amami Oshima to decrease Habu Vipers and Black Rats. However, because mongooses are diurnal and both Habu Vipers and Black Rats are nocturnal, theintroduction of mongooses did not lead to a large number of predation on the snakes andthe rats, and decreasing their populations. On the other hand, young Amami Rabbits, which
spend the daytime in their burrows, and the Amami Woodcocks, which make their nest on the
ground, became preferred prey animals of mongooses, and consequently their population sizes
have decreased. The release of mongooses into the island with the hope that they would decrease the populations of Habu Vipers and Black Rats led to an unforeseen result: the decreaseof the native species on Amami Oshima.

Problem

3

Amami Spiny Rat

Vanishing of indigenous specieson the Island

From analyses of the stomach contents and fecal samples of mongooses, the remains ofanimals such as Amami Rabbits and Amami Spiny Rats were presented. It was also confirmed that mongooses ate amphibians such as Amami Ishikawa’s Frogs as well as reptiles
such as Okinawa Tree Lizards. The populations of such native species on Amami Oshima
decreased as the mongoose population increased.

Animals predated by mongooses
A mongoose invading in a Amami Rabbit burrow(photo by Fumio Yamada)

食性分析

A mongoose eating Ryukyu Green Snake
Mother checking her baby in its
burrow

Problem2

A mongoose come into the burrow

spread whole the Island
Release point(1979)

The mongooses released in central part of theisland in 1979 gradually dispersed across a wide
area on the island. By 2010, mongooses could
be found in Uken village, which is located in
the southwestern part of Amami Oshima. Thirty mongooses are said to have been releasedon Amami Oshima in 1979. It is estimated thatthe population of mongooses on the island increased to about 10,000 by the year 2000.

Distribution ofmongooses

Amami Rabbit fur in amongoose feces

A mongoose left the burrow after
two minutes later

Population growth andOkinawa Tree Lizard(photo by Fumio Yamada)Conservation of endemic species
Task

on Amami-Oshima Island

The only way to protect the native species on Amami Oshima was to reduce the population size of mongooses by capturing them. In order to do this, community organizations
and local governments began investigating the impact of mongooses to native animals,
and also started capturing efforts.

Recovering of several species through the eradication programme

Ryukyu Long-haired Rat

Amami Tip-nosed Frog

Monitoring of wild animals indicate gradual recovery of distribution of several native species, such as the Ryukyu Long-haired Rat and the Amami Tip-nosed Frog, in the areas where
the mongoose gave the degradation of status of the indigenous species on the Island.

6

Checking a trap

7

Mongoose

マングース
eradication
防除事業
project

Restoration of original
ecosystem withoutmongoose

1979･ Release of the mongooses introduced from Okinawa
Island into Amami Oshima

1989

estimated
population
size･ Commencement of study on ecosystem damage by the▼mongooses (Mammalogical Society of Amami)

1,000
If things don’t change, the animals on Amami Oshima
will be gone. With the support of the people of the

6,000

island who had such concerns, a full-scale mongoose
eradication project was started in the year 2000. The
Alien Species Act was commenced on Amam Oshima inmongooses from Amami Oshima.

･ Launch mongoose control programme to prevent agricultural products (Local governments)

1996･ Launch study on status and a model control programme(MOEJ and Kagoshima Prefectural Gov.), and subsidy as a
nuisance animal control (Kagoshima Prefectural Gov.)

mongoose eradication project based on the Invasive2005. The goal of the project is to completely eradicate

1993

A m a mi T

hrush

10,000 2000

･ Start full control program of the mongooses as nuisanceanimal control (MOEJ)

1979 〜

Prehistory of mongoose
eradication project

Kinsakubaru, a protection forest on the Island, was a habitatof many endemic species such as Amami Rabbit, Amami
Ishikawa’s frog, and Amami Woodcock before the release of
the Small Indian Mongooses. After the release of the predatory animals in 1979, the population of the endemic species
have decreased in the Kinsakubaru which locates near themongooses release area.
People on the Island expected decrease of the Habu Viper
through the mongoose predation, however, several people
noticed biodiversity degradation on the Island by the mongoose release. The Mammalogical Society of Amami was
one of the groups which gave warnings to the mongoose
release issue. The member of the Mammalogical Society ofAmami started study on ecological damage by the mongooses from 1989, when several agricultural damages occurredby the mongooses. The study on food habits of the mongooses showed predation on precious endemic species by the
animals, and gave caution against the issues to the people on
the Island.

2003

Establishment and activities ofAmami Mongoose Busters
The mongoose control programme started since
2000. At the beginning stage of the project, voluntary member of hunter association supported thecontrol of animals using traps, and the local governments payed subsidies. Quite a lot of the mongooses were captured by the programme, and regular monitoring showed decrease of density index
of the animals. But, eradication of the animals wasdifficult because trapping in mountain areas was
hard task for the voluntary members. Therefore,
the Amami Mongoose Busters (AMB) was organized for eradication of the mongoose from wholeareas on the Island in 2005. People on the Island
expected AMB to contribute recovery of the indigenous species such as Amami thrush and endemic
flogs through the mongoose control project. AMB
started the activities based on these backgrounds.

･ Finish the nuisance animal control program by the local
governments

5,000

2005

･ Enforcement of the Invasive Alien Species Act (MOEJ)･ Start the mongoose eradication project on Amami
Oshima (MOEJ) ･ Establishment of the Amami Mongoose
Busters (AMB) ･ Formulating mongoose control plan on
Amami Oshima (MOEJ)

1,300
150

2007

･ Introduction of mongoose detection dogs for the control project (AMB)

2013･ Formulation second period of mongoose control
plan (MOEJ)

2017･ Revision the second period of mongoose control
plan (MOEJ)･ Establishment the Amamigunto National Park (MOEJ)

10

2018
･ Capture only one mongoose from April 2018 to March
2019 due to decrease of the mongoose population (AMB)

Future 2022
Expecting eradication of the mongooseon Amami-Oshima Island
8

2005 〜

A photo of AMB member at a day

平成 19 年2013 〜
Second period ofmongoose control planin Amami-Oshima Island

平成The
25年
Invasive Alien Species Act was enforced since2005 and the Invasive Alien Species (IAS) can becontrolled by the mitigation plan. The Small Indian
Mongoose is also stipulated as the IAS by the Cabinet Ordinance of the Act, and the mongoose control plan on Amami Oshima was authorized by the
MOEJ. The control plan was conducted according
to the plan, and eradication is shown up throughthe systematic data on status of the animals gathered by the project and exclusion in spot areas.
“The second period of mongoose control plan” wasestablished in 2013 based on the achievement of
the first period. The second period plan indicates
eradication of the mongoose from Amami Oshimaby 2022, and the AMB and other relevant organizations conduct the mongoose eradication project.

9

Professionals
to conserve theecosystem on
Amami Oshima

Amami Mongoose
Busters!

Restoration of the native
species to AmamiOshima Island
Monitoring of the native species
In order to monitor the restoration of native species as a result of the decline of the mongoose population, monitoring for the native animals arebeing carried out. The sensor cameras which set in various places on the
Island show steady recovery of distribution area of Amami Rabbit, Amami
Spiny Rat, and Amami Woodcock. AMB note the locations in where theyobserve the animals or hear voices of the native species during the routine
works of trap sites checking. For the Amami Mongoose Busters, observing
the restoration of the populations of the native animals on Amami Oshima
through daily activities enables the members to confirm the achievementsof their eradication project for mongooses. They are proud of what they
have achieved.

The Amami Mongoose Busters was formed in 2005 withthe aim of eradication of mongooses and restoring thenative animals on Amami Oshima. It is an organizationof professionals that strives to protect the wildlife of
Amami Oshima. These professionals have the skills to
capture mongooses, the power to climb mountains, theknowledge about wildlife, and are passionate about
eradication of mongooses.

The most effective
method of reducing themongoose population

An effective tool forthe mongooses

Catching by the traps

catch them by traps. The Amami Mongoose Busters captures mongooses
with live traps and weasel traps.
A new long pipe trap was developed for more effective control of themongooses and they are used mainly
in areas where by-catches of Amami
Spiny Rat occur frequently. More than
30,000 traps are set systematically tocover whole areas in where the mongoose detected on the Island.
Live Trap

captured has decreased conspicuously

In order to catch mongooses more effectively, AMB introduce detection dogs,
which track down mongooses and findtheir burrows. The mongoose detection dogs have a good sense of smell
and special abilities of motion, and aretrained to follow the direction of personsof the programme. Handlers of AMB
give training the dogs, and they use thedogs passed the examination in field.
The mongoose detection dogs go to theforests to detect smell and feces of theand the eradication of the animals is

Chemical control
mongooses with the handlers, and ifthey find hiding holes of the animals, thehandlers try to catch them. The numberof captured mongooses using the dogs is
as many as the number of captured it bytraps in 2014. According to the decreaseof population size of the mongoose, thenumber of captured animals is also decreasing, however, the dogs are expected
to confirm eradication of the mongooseon the Island. The role of the dogs is still
important for eradication.

sor camera (take photo using infrared

検索犬の発見による捕獲頭数
No. of capture

sensor), hair traps (take hairs of mon-35

gooses) and mongoose detection dogs

30

32

25

Weasel Trap

捕獲数

animals in order to confirm the eradi-

Although population decline of the mongoose, AMB has encountered anissue in 2016. They found a high-density area of the mongooses in roadsideslope. The area was covered by rock fall prevention nets, which hampered
trapping and work of the mongoose detection dogs. AMB and MOEJ
considered use of chemical control for the eradication in the area. They
introduced a chemical material which contains “Diphanocinone” as principal element and usually use for mouse and rat control. They made poisonbates contained the Diphanocinone, and put them in the area in April 2017
and March 2018. After spreading the poison bates, the sensor cameras
never took photo of the mongoose, and no trapping of the animals in andaround the area. The chemical control of the mongoose is the first case inJapan, and it is an important step to the successful eradication.

Number of captured mongooses bydetection dogs

coming realistic target. AMB use sen-for the monitoring and catching the

Trump for successful
eradication

Detection dogs

The most effective method of reducing the mongoose population is to

Because the number of mongooses

searching

Photos of a Ryukyu Long-haired Rat (upper) anda mongoose (lower) taken by sensor cameras.

cation.

20
15
10
5

1

0

All members of dog handler anddetection dogs in 2019
Hair Trap

10

20
08
20
09
20
10
20
11
20
12
20
13
20
14
20
15
20
16
20
17
20
18

0

sausage baits using chemical control

Mongoose eating a sausage bait

11

Eradication of mongooses in the near future

4000

3000000

3500

2500000

3000

2000000

2500

1500000

2000

successful in eradication of the mongooses, and there areno large Islands such as Amami Oshima (712 km2) that havebeen successful in complete removing mongooses in theworld. If Amami Oshima is successful in eradication of mongooses, it will give a great deal of hope to people aroundthe world who suffer from damage caused by mongooses.
Although many challenges still remain, it appears that weare close to making our ambition come true.

Decreasing in mongoose population
1500

More than 32,000 mongooses have been captured on Amami Oshima by 2012. The number of traps
0

contrast, the number of mongooses caught by the traps in a year has continued
01 02 03 to
05 06 07 0 8 CPUE
09 10 11 12 13 14 15 16 17 18
04 decrease.
indicates decrease of densities and almost vanishing population of the mongooses in recent years.

Annual changes in the number of
capture and effort

Annual changes in CPUE
3000000
2500000

3000● Points of capture

FY2006

Tatsugo Town
Uken Village

The maps of trapping sites of the mongooses indicate population decline and dividing of range in the central area of theIsland from 2006 to 2012. In 2018, AMB caught the mongoose
only 1 sites. The trapping efforts has steady increased from2006 to 2018. The high-density trapping and introduction of
the mongoose detection dogs have contributed the decline of
the mongoose population and catching sites.

Amami City
Yamato Village

Setouchi Town

FY2012020 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20

4000

Scattering and disappear ofrange of mongoose

500000500

has increased significantly since 2005, when the Amami Mongoose Busters started its activities. In

3500

Changes in capture points

1000000

1000

2000000

2500

1500000

2000

0.6
0.5
0.4
0.3

1500

1000000

1000

500000500
001 02 03 04 05 06 07 0 8 09 10 11 12 13 14 15 16 17 18
20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20

0

Since the Amami Mongoose Busters started its activities, there has
been a drastic increase in the total number of traps (see the line
graph). The total number of trap days has kept around 2 million every
year since 2009. The number of mongooses caught (see the bar graph)has shown
0.6 a declining trend since 2007, and been a significant drop in
the number in recent years.

0.2
0.1
0.0
20
07
20
08
20
09
20
10
20
11
20
12
20
13
20
14
20
15
20
16
20
17
20
18

The original habitat of the Small Indian Mongooses introduced to Amami Oshima is South Asia. The mongooses wereintroduced to many places for controling rats and other animals, and have become established as an invasive species
on many other islands (e.g., islands in the Caribbean and
Hawaii). They have caused problems such as predation onnative species, damage to farm production in many places
introduced.
Only small islands with an area of less than 4 km2 have been

CPUE(Catch per Unit Effort) , an indicator of mongoose
population size, has continued to decrease.
35

30
25
20

0.5

15

0.4

10
5

Mongooses have steadily decreased ！!
0.3

0

20
08
20
09
20
10
20
11
20
12
20
13
20
14
20
15
20
16
20
17

0.2

0.1
0.0

20
07
20
08
20
09
20
10
20
11
20
12
20
13
20
14
20
15
20
16
20
17
20
18

Can we eradicate mongooses perfectlyin Amami-Oshima Island ?
Estimated population
35

FY2018We estimatethat the population of the mongooses is maxi30
mum 1025individuals in 2018. Based on the results of a computer
simulation,
it is expected that if mongooses continue to be
20
15 at the current efficiency, the total population will be
capturedclose to10zero by around the year 2020. The smaller the mon5
goose population,
the more difficult it will be to catch them.

20
08
20
09
20
10
20
11
20
12
20
13
20
14
20
15
20
16
20
17

0
Therefore,
things may not go as expected. However,eradica-

Estimated population
500
450
400
350
300
250
200

tion of mongooses from the Island in the near future, we have150

to continue trapping efforts and monitoring by the sensor

100

cameras to confirm the eradication of mongoose for long time.

50
0
2010

Distribution of mongooses have decreased !
12

2011

2012

2013

2014

2015

2016

2017

2018

Eradication will be accomplished soon!
13

No more mongooses andhealthy forest ecosystem
Native species recovery as a result of
decreasing of the mongooses

Native species have been recovered

The native species of Amami Oshima have recovered inparallel with the decline of the mongooses. Monitoring

Native species have been recovered, which are shown by sensor camera monitoring and observation data from theMongoose control project. The number of photos of Amami Thrush and Amami Woodcock taken each day gradually increase by decreasing of mongoose population.

by AMB and other studies indicates the successful recoveries of the many species.

Recovery of native species
The decrease of mongooses has brought the recoveries of historic range of the native species. The
presences of the Amami Rabbit and the Ryukyu Long-haired Rat show the maximum 8-km expansion of their ranges from 2011 to 2017. The range of Amami Ishikawa’s Frog has also recovered andspreaded in late years. The frogs especially expand their ranges in Naze and Tatsugo, high-density
areas of the mongooses before, and is confirmed in Kinsakubaru no presence area in late 2000s.

2011

2017

2011

2020
1515

0.20.2

1010

5050

2016
2008
20082010
20102012
20122014
20142016

Results of nightroad census

1.0

N

Ryukyu Long-haired Rat
2011→

2011

2017

8
6

late 2000'S →0
2002

These graphs show the number of animals
observed while slowly driving along a 41.1
km long forest road at night. The verticalaxis indicates the number of animals detected per one survey, and the horizontal axis
indicates the year of studies.

late2010'S

2006 2009 2011

2017

0.6
0.4
0.2
0
2002

2006 2009 2011

Otton Frog

4

0.2

0.8

Amami Ishikawa’s Frog

Amami Rabbit

0.4
1.2

0 0
2002
2002 200
20

2017
2017年

2016
2008
20082010
20102012
20122014
20142016

1.2

0.6

10km

2 2

0 0

0 0

0.8

0

4 4

0 0
2002
2002 2006
20062009
2009
2011
2011

5 5

Naze

6 6

0.60.6
100
100
0.4
0.4

1.0

Kinsakubaru

Santaro-toge

No.
No.
of of
photosphotos
at at
1,000
1,000
trap
trap
days
days
1.0
1.0

2525

Honcha path

8 8

150
150
0.8
0.8

2020

2017

2017

Amami Woodcock

1.21.2

No.No.
of ofphotosphotos
at at
1,000
1,000
trap
trap
days
days
3535

The figure shows historical changes of photos taken rate of Amami thrush and Amami
Woodcock by sensor cameras (number ofphotos taken per 1,000 trap days). The
photo taken rates has increase notably ineastern part of Naze area in where the mongooses have declined remarkably.

Amami Rabbit
2011 →

Amami Thrush

Results ofmonitoring using
sensor cameras

2017

8

20.4
0.4

6

00.3
0.3
2002

4

0.20.22

0.10.10.30.32006 2009 20112017

0.20.20.10.1

0 0
0
0 0
2002
20062011
2009
2009
2011
2011 2017 20172017年 2002
2002 200
20
2002 2002
2006 2006
2009

2017

Amami Tip-nosed Frog

Honcha path

2017

2011

Naze
late
2010'S

1.2
Kinsakubaru

late2010'S

1.0

Kinsakubaru

Santaro-toge

0

0.8

late
2000'S

N

10km

late
2000'Slate
2010'S

0.6

N

0.4
0

4km

This figures show results of native species monitoring. Lines indicate the edges of observation points. Changes from 2011 to 2017 areshown in Amami Rabbit and Ryukyu Long-haired Rat, late 2000’s to late 2010’s is shown in Amami Ishikawa’s Frog.

14

Amami Ishikawa’s Frog

late
2000'S

Naze

0.2
0
2002

Photo of study site

2006 2009 2011

2017

8

0.4

6

0.3

4

0.2

2
0.4

0.1

0
0
0.3
2009 2011
2002 2002
2006 2006
2009 2011

0.3

0.2

0.1

1.51.50.3

2017 2017
0.2

0
2002

1.01.02006 2009 2011

Watari et al. (2013) modified

0.2
0.1
0

2017

0.1

0.50.50 0

015