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1
A risk management model for deer population in the
Yakushima World Natural Heritage
H Matsuda*, A Ohta, S Tatsuzawa, H Takahashi, K Tokida,
http://risk.kan.ynu.ac.jp/matsuda/
NewsI am looking for 11 postdocs of a JSPS grant: Global Eco-Risk Management from Asian Viewpoints (http://risk.kan.ynu.ac.jp/gcoe/)
2
Aims of this researchSika deer Cervus nippon yakushimae (endemic subspecies) damages on natural vegetation and endemic plants
A population dynamic model to propose a management plan
3
What areas should we protect?
• Areas that include many rare plantshigh vegetation damage by deer– Logging roads may enhance deer dispersal and
outbreak throughout the island
• Areas that include many rare plants without heavily vegetation damage– Few chance of dispersal and high hunting
pressure
From Tet Yahara’s idea
2007/8/7
4
< 1000 deer?
GPS points of deer by spotlight count (2005)
一湊
永田
大川林道
小楊子林道
栗生 モッチョム農道
安房林道
荒川林道
白谷線
宮之浦
安房線安房
長峰
小瀬田
Western
zone
林道
永田岬
中間林道
小瀬田林道
船行農道
湯泊林道 中瀬川林道
尾の間
4000-8000 deer?
3000-6000 deer?
Northeastern zone
Southern zone
Western zone
Data obtained & compiled by Tatsuzawa & Takahashi2007/8/7
5
Increase of spotlight counts of deer (Tatsuzawa & Takahashi, unpubl. data)
•0.33 → 0.92 deer/km, from 1995 to 2005•Deer is overabundant in Western zone and Northeastern zone•Deer is relatively fewer in Southern zone
1995 2005
2007/8/7
6
The number of removaljust 300 removal in Yakushima Island.
0
200
400
600
1 9 7 0 1 9 8 0 1 9 9 0 2 0 0 01 9 7 2 1 9 7 4 1 9 7 6 1 9 7 8 1 9 8 2 1 9 8 4 1 9 8 6 1 9 8 8 1 9 9 2 1 9 9 4 1 9 9 6 1 9 9 8 2 0 0 2
熊毛四島
上屋久町
屋久町
(含馬毛島)Kamiyaku Town
Yaku Town
2000199219801970
Kagoshima Pref. & Serow Tatsuzawa
4 Islands in Kagoshim Pref.
2007/8/7
Kamiyaku Town
Yaku Town
7
Agricultural damage by wildlifein Yakushima Island.
0
2000
4000
6000
8000
10000
12000
14000
16000
サル
シカ
ヒヨドリ
カラス
19
87
19
92
20
02
19
97
(千円)
Yakushima cho
Monkey
Deer
}Birds
Dam
age
(tho
usan
d ye
n)
2007/8/7
8< 1000 deer?
Northeastern zone
Southern zone
Western zone
Zone-dependent deer management plan
2007/8/7
1) 3000-6000 deer?2) >300 s3) Depends on hunting effort
1) 4000-8000 deer?2) We need to
hunt >400-800 s
3) We give up to control!
1) 4000-8000 deer?2) We need to
hunt >400-800 s
3) We give up to control!
1) <1000 deer?2) 100-150 s3) We try to decrease deer
9
Zoning planNortheastern zone
Southern zone
Western zone
■National forest■ Deforested area■ Orchard
Serow Tatsuzawa
一湊
永田
大川林道
小楊子林道
栗生 モッチョム農道
安房林道
荒川林道
白谷線
安房線安房
長峰
小瀬田
Western
zone
林道
永田岬
中間林道
小瀬田林道
船行農道
湯泊林道 中瀬川林道
尾の間
Aiko-dakeProtected
zone
http://www.rinya.maff.go.jp/sekaiisan/introduction/yakushima/001.html
World heritagearea (107km2)
1) 3000-6000 deer?2) >300 s3) Depends on hunting effort
1) <1000 deer?2) 100-150 s3) We try to decrease deer
2007/8/7
1) 4000-8000 deer?2) We need to
hunt >400-800 s
3) We give up to control!
1) 4000-8000 deer?2) We need to
hunt >400-800 s
3) We give up to control!
10
A population dynamic model
3 habitat model with environmental stochasticity
# 0 year old
# adult femals
# adult males
Repro. Success. R(t)
Recruit from 0 yr old Adult survival Catch
Survival rate S
11
Adaptive catch quotas
Hunting effort depends on the monitored population index
Pop. level
1 2 3 4 5
North-east zone
0-10001000-2000
2000-4000
4000-5000
5000-
Southern zone
0-200 200-500 500-700700-1000
1000-
Hunting %α 0 0.13 0.2 0.3 0.45
Catch limit 0 - - 1000 1000
12
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
0 2 4 6 8 10
Results when catch limit = 1000
0
100
200
300
400
500
600
700
800
900
1000
0 2 4 6 8 10
Year after present Year after present
NorthEast & South 95%CI>30% decline is expected 100
0
500
300
We might catch ca. 1000 deer for >10 yrs.
1
0.5
Pop
ulat
ion
inde
x N
(t)/
N(0
)
Cat
ch in
num
ber
13
3 monitoring site plan Northeastern zone
Southern zone
Western zone
Aiko-dakeMountain
& catchment
Onoaidapathway
Seibu-rindo logging road
2007/8/7
14
http://www3.ocn.ne.jp/~yakusima/eco2.tizu2/tizu2.htm
Aiko-dake Mountain Protection Area plan
• Villages including Onna-gawa riv. Catchment
• River boundary!
• Monitor Catch statistics of female deer
• Estimate deer population size
2007/8/7
Why do we use river boundaries?
• Deer dispersal is often limit by rivers.
• Villages are usually divided by rivers.
• Catch statistics by hunters are easily compiled by areas between rivers
• Therefore, a region between rivers is used as a relatively isolated deer habitat.
152007/8/7
16
Intensive Monitoring of Ono-aida path plan
• Villages between Taino-kawa Riv and Suzu-kawa Riv.
• Monitor Vegetation and Plant Species
• Monitor Catch Statistics of 9Female Deer
• Estimate Deer Population Size
2007/8/7
17
Seibu-rindo logging road monitoring site
• Business as usual
• Monitor natural increase of deer by spotlight count and density estimation.
• Monitor damage on natural vegetation
• Monitor endemic threatened plant species.
2007/8/7
18
Monitoring deer population
• Sex, stage, zone-dependent Catch statistics• Catch per unit effort (hunter sampling)
– Catch position (GPS), time, sex (CPUE in national forest)
• Spotlight count along routes 77-78 and logging roads
• Altitude-dependence in deer density– Automatic monitoring by night vision; – Line transect survey along Anbo-rindo logging road,
Onoaida path, Aiko-dake Mountain Prot. Area
2007/8/7
19
Management plan
• Test effect of deer on natural vegetation– Vegetation recovery survey inside of fence
• Reducing agroforest damage– Hearing of farmers and citizens– Improving population dynamic model
• Promoting sustainable use of deer meet• 1000 catch is short for the Western Zone.
2007/8/7