An adaptive management for sika deer based on sex-specific hunting

1. http://risk.kan.ynu.ac.jp/matsuda/2005/050801IMC.html An adaptive management for sika deer based on sex-specific hunting H. Uno, T Fujimoto, T. Saitoh, K. Kaji, T. Kurumada, H. Hirakawa, H. Matsuda, K. Tamada,

2. Year (source: Hokkaido Prefecture) History of over-harvesting and hunting-ban Heavy winter Extinction of wolves

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

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.

5. Stage-Structured Model 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)] ,

6. 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)

7. Population Indices Catch & site per unit effort (per hunter per day) Spotlight census Aerial (helicopter) census Traffic accident of JR trains (and cars) Damage on agriculture and forestry I don’t know the absolute population.

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)

9. (d) Accept 10-fold fluctuation (c) error in life history parameters (b) Process errors (heavy snows) (a) No process nor measurement errors Risk management based on a population dynamic model

10. Density-dependent hunting pressurehttp://www.hokkaido-ies.go.jp/HIESintro/Natural/ShizenHP2/SIKA/DTdeerHP.htm %P>50%P1993 Emergency culling 25% < %P Gradual population reductions (catch females) 5% < %P Gradual population increases (catch males) %P <5% or after the severe winter Hunting bans

11. Population indices in 1003=100% 1990 1995 2000 2003 year Trends in Population indices

12. Summary • We consider a management policy for a sika deer (Cervus nippon) population in the eastern Hokkaido. • To make a robust program based on uncertain information 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.

14. Possible factors of deer over-abundance • Success in deer hunting-ban • Forest cutting and spread grassland • Winter warming • Extinction of wolves （ca.1890）

15. Spatial distribution of sika deer during 1925-1997 Source: Hokkaido Prefecture Akan Taisetsu Hidaka