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An adaptive management for sika deer based on sex-specific hunting
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Transcript of An adaptive management for sika deer based on sex-specific hunting
10/8/05 1
An adaptive management for sika deer based on sex-specific hunting
H. Uno, T Fujimoto, T. Saitoh, K. Kaji, T. Kurumada,H. Uno, T Fujimoto, T. Saitoh, K. Kaji, T. Kurumada,
H. Hirakawa, H. Matsuda, K. Tamada,H. Hirakawa, H. Matsuda, K. Tamada,
http://risk.kan.ynu.ac.jp/matsuda/2005/050801IMC.html
10/8/05 2
History of over-harvesting and hunting-ban
Year (source: Hokkaido Prefecture)
10
100
1,000
10,000
100,000
1,000,000
1875 1895 1915 1935 1955 1975 1994
Catch
Heavy winter
Extinction of wolves
10/8/05 3
Purposes of deer management in eastern Hokkaido (1997)
To use deer as natural resources, To avoid extinction and overabundance
of deer, To conserve ecosystems, To decrease damage on agriculture and
forestry
10/8/05 4
Deer Management Program in eastern Hokkaido (1997)
Feedback control for non-equilibrial population
Risk management incorporating heavy snow years (process errors) and measurement uncertainties into account.
Public involvement by disclosure and discussion in mailing list.
10/8/05 5
Stage-Structured Model
)(
)(
)(
)(0)(
0)()(
0)()(0
)1(
)1(
)1(
tN
tN
tN
tLtL
tLtL
tLtr
tN
tN
tN
m
f
c
mmmc
fffc
ff
m
f
c
Lfc(t)= Lmc(t)= exp[-Q(t)Hc(t)]exp[-Mc(t)]exp[-Rc(t+1)],
Lff(t) = exp[-Q(t)Hf(t)]exp[-Mf(t)]exp[-Rf(t+1)] ,
Lmm(t) = exp[-Q(t)Hm(t)]exp[-Mm(t)]exp[-Rm(t+1)] ,
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Assuming uncertainties
Survival rate of juveniles Lfc: 46% ~ 54%
Survival rate of female adults Lff: 90% ~ 99%
rLff = λ(λ- Lff)/ Lfc
Temporal fluctuation <10% Measurement error of population index <20%
I use parameter sets only when the rate of natural population increase λ : during 15-20% per year (“filtering method” instead of sensitivity analysis)
10/8/05 7
Population IndicesCatch & site per unit effort (per hunter
per day)Spotlight censusAerial (helicopter) censusTraffic accident of JR trains (and cars)Damage on agriculture and forestry
I don’t know the absolute population.
10/8/05 8
Sex-specific hunting
Width of catch fluctuation
> Width of population fluctuation
Catch females to decrease, and catch males to increase.
Sex-specific hunting stabilizes annual catch
We must monitor sex-ratio (1:2 - 1:10)
10/8/05 9
Risk management based on a population dynamic model
0%
2%
4%
6%
8%
10%
12%
2007 2022 2037 2052 2067 2082 2097
Year
Rep
rodu
ctiv
e P
oten
tial
0
1000
2000
3000
4000
5000
6000
7000
Yie
ld
(c) error in life history parameters
0%
1%
2%
3%
4%
5%
6%
7%
8%
9%
2007 2022 2037 2052 2067 2082 2097
Year
Rep
rodu
ctiv
e Po
tent
ial
02004006008001000
12001400160018002000
Yie
ld
(a) No process nor measurement errors (b) Process errors (heavy snows)
0%
10%
20%
30%
40%
50%
60%
2007 2022 2037 2052 2067 2082 2097
Year
Rep
rodu
ctiv
e Po
tent
ial
0
2000
4000
6000
8000
10000
12000
14000
Yie
ld
(d) Accept 10-fold fluctuation
10/8/05 10
Density-dependent hunting pressure http://www.hokkaido-ies.go.jp/HIESintro/Natural/ShizenHP2/SIKA/DTdeerHP.htm
%P>50%P1993 Emergency culling
25% < %PGradual population
reductions (catch females)
5% < %PGradual population increases (catch males)
%P <5% or after the severe winter
Hunting bans
10/8/05 11
Trends in Population indicesP
opul
atio
n in
dice
s in
100
3=10
0%
year1990 1995 2000 2003
10/8/05 12
Summary We consider a management policy for a sika deer (Cer
vus nippon) population in the eastern Hokkaido. To make a robust program based on uncertain informat
ion about the deer population, we consider 4 levels of hunting pressures.
The hunting pressure for females is set to increase with the population size.
The simulation results suggest that management based on sex-specific hunting is effective to diminish annual variation in hunting yield.
10/8/05 13
10/8/05 14
Possible factors of deer over-abundance
Success in deer hunting-ban Forest cutting and spread grassland Winter warming Extinction of wolves ( ca.1890)
10/8/05 15
Spatial distribution of sika deer during 1925-1997
Source: Hokkaido Prefecture
AkanTaisetsu
Hidaka