Biodiversity Conservation

Session 2

Conservation of Threatened Species in Ryukyu Islands toward listing as a World Natural Heritage Site

Noriaki SAKAGUCHINaha Nature Conservation Office, Ministry of the Environment

November 22, 2011

Fauna in Ryukyu Islands and Its Characteristic

Crested Serpent Eagle

Iriomote cat

Ryukyu lomg haired rat

Amami rabbit

Spiny rat

Ishikawa’s frog

Okinawa RailOkinawa woodpecker

About 60 endemic species or subspecies of mammals, birds, reptiles and amphibians in Ryukyu Islands. 

Geohistorical Factor Caused Endemic Species

ix) Representing significant ecological and biological processes in the evolution and development of terrestrial ecosystems and communities of plants and animals

x) Containing the most important habitats for in-situ conservation of biological diversity, including threatened species of universal value on science or conservation

Ryukyu Islands Meet Criteria for World Heritage

Most of those endemic species are listed on the Red List, MoE-J

Red List of MoE‐JNo. of endemic species* CR EN VU Total (%)

Mammals 24 6 12 018

(75.0)

Birds 19 4 1 49

(47.4)

Reptiles 43 3 7 1323

(53.5)

Amphibians 20 0 5 49

(45.0)

* including sub‐species

Number of Threatened Species among Endemic Species in Ryukyu Islands

Factors Threatening Endangered Species and Measures for Addressing the Challenges

Factors

Deforestation and Habitat DegradationRoad Kills (Traffic accidents)

Invasive Alien Species

Poaching and illegal tradesChallenges for the designation of the World Heritage

Big Challenges toward World Heritage

1. Eradication of the Mongoose threatening endangered species

Eradication Project of Mongoose

2. Establishment of a protected area to secure endangered species’survival

Identification of important areas, using monitoring research data

In Okinawa Island

Small Indian Mongoose (Herpestes javanicus)One of the 100 of the World's Worst Invasive Species

released in 1910

（1978年）

（2004年）

Okinawa Is.

BW: 0.3 – 1 kg BL: 30 – 40cm TL: 25 – 30cmOriginal Distribution: Malay Peninsula to Middle EastDaily activity: Diurnal Food habits: Omnivorous (mammal, bird, reptiles, frogs

insects, fruits)Law: IAS by Invasive Alien Species Act (2005)Introduction: Ryukyu: Okinawa (1910), Amami (1979)

Other areas: Cuba, West Indies, Fiji, Hawaii

Released in 1910

Okinawa Is.

1978

2004

2000 2003 2006

Expansion of Mongoose Distribution

Impacts on Endangered Species in Yambaru, Okinawa

Distribution of the Okinawa Rail and Mongoose in 2005

Okinawa Rails Mongooses

No. of captured      mongooses in each meshConfirmed

UnconfirmedUnsurveyed

South edge of distribution In 1986

2005

Mitigation Plan of the Small Asian Mongoose in the Northern Part of Okinawa Island

drawn up in 2005 in accordance with the IAS Act

Area: Northern part of Okinawa Island (Yambaru), Okinawa PrefectureDuration: April, 2006 – March, 2015Goal: In collaboration with Okinawa prefectural gov.,

MOE-J, in 10 years, completely eradicates the mongooses in the Yambaru., which are causing serious damages on endemic and endangered animals and a subtropical forest ecosystem in the area, and halts the species from re-entry.

Activities: - Intentional Capturing by more than 30 experts and 1 million capturing efforts per year

- Introduction of dogs for searching and capturing - Preventing mongooses from entering the Yambaru by constructing fences

- Monitoring research for evaluation of the project: mongoose and endangered species

The Number of Captured Mongooses by TrappingCa

ptured

 Mon

gooses

CPUE (N/100

TD)

Captured Mongooses CPUE

78,576

131,631

105,895

119,734

189,037

279,710298,791

362,553914,842

1,198,282

1,303,149

488,338

20112009 2010200820072005 200620042003200220012000

The number of captured mongooses and its CPUE with trapping efforts (trap days)

Distribution of Captured Mongooses

CPUE (N/100TD) of captured mongooses in each mesh

2008 2009 2010 July, 2011

1‐ 23‐ 56‐1011‐1516‐27

1‐ 23‐ 56‐1011‐1516‐21

1‐ 23‐ 56‐1011‐1516‐22

1‐ 23‐ 5

The number of captured mongooses in each mesh

Challenges to complete eradication of mongoose

The number of Ryukyu longhaired rats bi-catched by trappings has being increasing.

0.000

0.003

0.006

0.009

0.012

0.015

0

40

80

120

160

200

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

CPUE(No pe

r 10

0 Traps)

No of captured rats 

Death by kill traps Captured and released by live traps

CPUE (number / 100TD)

As mongooses has been decreased, the distribution and number of Ryukyu longhaired rats are expanding and increasing in Yambaru.

Kill trap Live trap

2008 2010

2009

（

3

1

2007

2

Expansion of the Distribution of Ryukyu Longhaired Rat

Adaptive Capturing to Reduce the Bi-catch Risk of the Ryukyu Longhair Rat

FY2008

FY2009

FY2010

The Ryukyu longhaired rat mainly bicatched from December to March.

Using kill traps except in this periodin its higher density areas.

0

50

100

150

200

FY2007 FY2008 FY2009 FY2010

Longhaired rats number

0

20

40

60

80

100

FY2007 FY2008 FY2009 FY2010

1

Mongoose number

0.000

0.100

0.200

0.300

0.400

FY2007 FY2008 FY2009 FY2010

Mongoose CPUE

0.000

0.020

0.040

0.060

0.080

0.100

FY2007 FY2008 FY2009 FY2010

Longhaired rat CPUE

Mongooses are higher density in Area 1. Longhaired rats are higher in Area 2 and lower in Area 1.  Mongoose are the lowest and longhaired rats are comparatively high in Area 3.

Kill traps be used in Area 1 through the year and in Area 2 except December – March.  Kill traps not be used in Area3.

231‐3

1231‐3

1231‐3

1231‐3

Captured number and CPUE of mongooses and Ryukyu longhaired rats

Number of longhaired rats bicatched

2008

0

2

4

6

8

10

2009

0

5

10

15

20

2010

0

10

20

30

40

50

E     LApr

E     LJul

E     LAug

E     LOct

E     LNov

E     LDec

E     LJan

E     LFeb

E     LMar

E     LApr

E     LJul

E     LAug

E     LOct

E     LNov

E     LDec

E     LJan

E     LFeb

E     LMar

E     LApr

E     LJul

E     LAug

E     LOct

E     LNov

E     LDec

E     LJan

E     LFeb

E     LMar

Identification of Important Areas for Endangered Species

1 2 3 4 5

Ryukyu Longhaired Rat  Diplothrix legata ● ●

Ryukyu Spiny Rat  Tokudaia muenninki  ▲ ●

Okinawa Rail  Gallirallus okinawae ● ● ● ●

Okinawa Woodpecker  Sapheopipo noguchii ● ●

Ryukyu Robin  Erithacus komadori  namiyei  ● ● ●

Kuroiwa's Ground Gecko  Goniurosaurus kuroiwae kuroiwae ● ●

Ryukyu Leaf Turtle  Geoemyda japonica ● ●

Ishikawa’s Frog  Rana ishikawae ● ●

Okinawa Tip‐nosed Frog  Rana narina  ● ●

Holst's Frog   Rana) holsti  ● ●

Surveys conducted for monitoring endangered species

Surveys Data format1. Call back survey on Okinawa Rail by MoE call back number in each 1 km2 mesh2. Call back survey by mongoose project call back number in each 1 km2 mesh

3. Bicatch by Mongoose capturing CPUE (captured number / 100TD)

4. Night rout census by mongoose project Observed number / km in each 1 km mesh

5. Witness information collected by YWCC used for distribution data

Frequency  distribution  of  relative abundance and its grading

0

5

10

15

20

25

30

0.05

 0.10

 0.15

 0.20

 0.25

 0.30

 0.35

 0.40

 0.45

 0.50

 0.55

 0.60

 0.65

 0.70

 

0.75

 0.80

 0.85

 0.90

 0.95

 1.00

 

5 for top 10% meshes

1 23

4 Grade

Okinawa Rail

Distribution and Relative Abundance of Four Endangered Species

Ryukyu longhaired Rat Okinawa Rail Okinawa Woodpecker Ryukyu Robin

Identified Important Area in Yambaru

Total score of all 11 endangered speciesIn each mesh 

Total species number In each mesh 

Toward listing on the World Heritage Sites

We have to concentrate our efforts on

Eradication of invasive alien species

Establishment of protected areas,

Other necessary activities to secure endangered specie’ survival,

in cooperation with researchers and local communities

ご静聴ありがとうございました。

Thank you for your attention!