Harvest‐based Bayesian estimation of sika deer populations using state‐space models

Yamamura, Kohji; Matsuda, Hiroyuki; Yokomizo, Hiroyuki; Kaji, Koichi; Uno, Hiroyuki; Tamada, Katsumi; Kurumada, Toshio; Saitoh, Takashi; Hirakawa, Hirofumi

doi:10.1007/s10144-007-0069-x

Cited by 46 publications

(45 citation statements)

References 50 publications

(38 reference statements)

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“…Nevertheless, the reconstructed population showed a trend consistent with a population index that was independently observed in eastern Hokkaido. A population index based on a spotlight survey showed increases from 1992 to 1998 followed by stability after some reductions , Yamamura et al 2008. Thus, our estimates of the population through cohort analysis are reliable.…”

Section: Cohort Analysismentioning

confidence: 58%

Culling Versus Density Effects in Management of a Deer Population

Ueno¹,

Kaji²,

Saitoh³

2010

J Wildl Manag

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: Wildlife managers often manipulate hunting regulations to control deer populations. However, few empirical studies have examined the level of hunting effort (hunter‐days) required to limit population growth and demographic effects through harvesting of females. Moreover, the relative importance of density effects on population growth has not been quantified. We reconstructed a sika deer [Cervus nippon] population over a period of 12 years (1990–2001) using age‐ and sex‐specific harvest data. Using cohort analysis, we analyzed population dynamics, focusing on 1) the relationship between hunting effort and hunting‐induced mortality rate, 2) relative contributions of hunting mortality and recruitment of yearlings to annual changes in population growth rate, and 3) annual variation in recruitment rate. Population size increased until 1998 and declined thereafter. The population growth rate changed more in response to annual changes in recruitment rate than hunting mortality rate. Temporal variation in recruitment rate was not controlled by birth rate alone; direct density dependence, intensities of hunting mortality for fawns, and for females (≥2 yr of age), which accounted for the fawn survival rate, were required as factors to explain temporal variation. Density effects on the recruitment rate were not strong enough to regulate the population within the study period; high hunting mortality, with intensive female harvesting, was necessary to prevent population growth. Hunting effort was a good predictor of the hunting mortality rate, and female harvest had a negative effect on the recruitment rate through fawn survival. We suggest that >3,500 hunter‐days and prioritization of female harvesting are required to prevent increases in this deer population.

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Section: Cohort Analysismentioning

confidence: 58%

Culling Versus Density Effects in Management of a Deer Population

Ueno¹,

Kaji²,

Saitoh³

2010

J Wildl Manag

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“…It is well known that estimates using indices suffer from large observation errors when the probability of observation fluctuates widely; therefore, we applied statespace modeling to the harvest-based estimation combining a generalized linear mixed model (GLMM) with a Bayesian statistical model based on the population dynamic model. We first obtained GLMM estimates of population index by assuming two errors: (1) a lognormal error that was yielded by the 'local' random fluctuation of the expected number of observation, and (2) a Poisson error under the given expected number of observations (Yamamura et al 2008). The GLMM estimates obtained of population index still contain large errors that are caused by the 'global' random fluctuation of the probability of observation, that is, the fluctuation of the probability of observation which is synchronous over the whole area.…”

Section: Harvest-based Bayesian Estimationmentioning

confidence: 99%

“…Bayesian estimates of population indices that were obtained from the state-space model based on the stage-structured model(Yamamura et al 2008) and number of deer harvested from 1993 to 2008. Bold line the estimates of population indices, dotted lines SE.…”

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confidence: 99%

Adaptive management of sika deer populations in Hokkaido, Japan: theory and practice

et al. 2010

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We investigated the utility of adaptive management (AM) in wildlife management, reviewing our experiences in applying AM to overabundant sika deer (Cervus nippon) populations in Hokkaido, Japan. The management goals of our program were: (1) to maintain the population at moderate density levels preventing population irruption, (2) to reduce damage to crops and forests, and (3) to sustain a moderate yield of hunting without endangering the population. Because of significant uncertainty in biological and environmental parameters, we designed a ''feedback'' management program based on controlling hunting pressure. Three threshold levels of relative population size and four levels of hunting pressure were configured, with a choice of four corresponding management actions. Under this program, the Hokkaido Government has been promoting aggressive female culling to reduce the sika deer population since 1998. We devised a harvest-based estimation for population size using relative population size and the number of deer harvested, and found that the 1993 population size (originally estimated by extrapolation of aerial surveys) had been underestimated. To reduce observation errors, a harvest-based Bayesian estimation was developed and the 1993 population estimate was again revised. Analyses of population trends and harvest data demonstrate that hunting is an important large-scale experiment to obtain reliable estimation of population size. A serious side effect of hunting on sika deer was inadvertent lead poisoning of large birds of prey. The prohibition of the use of lead bullets by the Hokkaido Government was successful in reducing the lead poisoning, but the problem still remains. Two case studies on sika population irruption show that the densities set by maximum sustainable yield may be too high to prevent damage to agriculture, forestry, and/or ecosystems. Threshold management based on feedback control is better for ecosystem management. Since volunteer hunters favor higher hunting efficiency in resource management (e.g., venison), it is necessary to support the development of professional hunters for culling operations for ecosystem management, where lower densities of deer should be set for target areas. Hunting as resource management and culling for ecosystem management should be synergistically combined under AM.

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“…The estimated number of deer in 1993 was 17.1 ± 3.2 (910 4 ) in eastern Hokkaido (Units 9-12) and ca. 19 9 10 4 in 2005 (Yamamura et al 2008). In western Hokkaido (Units 1-8) in 1993, a population size of 11.1 ± 6.3 (910 4 ) was estimated; thereafter, the population increased, but with large margins of error in the estimates (Yamamura et al 2008).…”

Section: Deer Abundancementioning

confidence: 99%

Effects of deer abundance on broad-leaf tree seedling establishment in the understory of Abies sachalinensis plantations

Akashi

Unno

Terazawa

2011

Journal of Forest Research

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Browsing by sika deer (Cervus nippon) has significant negative effects on regeneration in many forests in Japan; however, the effects of browsing on regeneration processes have not been determined quantitatively. Our study was conducted in Abies sachalinensis plantations in seven tracts with differences in deer abundance on Hokkaido, northern Japan, to identify indicators for the effects of deer on the regeneration of broad-leaf species from observing seedlings. Five 5 9 20-m plots were located within each tract, and the densities of seedlings 30-200 cm tall and percentages of browsed seedlings were determined. We used sightings per unit effort (SPUE) by hunters and spotlight survey counts (SLCs) as indices of deer abundance for each tract. Seedling density was negatively correlated with deer abundance and coverage of dwarf bamboo, and basal areas of overstory trees also affected number of seedlings. Percentage of browsed seedlings was positively correlated with deer abundance, and it was affected by deer preferences among seedling species. However, the percentage of browsed seedlings was more clearly related to deer abundance than seedling density. There were few seedlings of tree species C100 cm tall in tracts with the highest deer abundance. Based on these results, deer abundances of SPUE [6 sightings per hunter-day or SLC [15 animals per 10 km are likely to prevent regeneration of broad-leaf species. The percentage of browsed seedlings and density and browsing damage on tree seedlings C100 cm tall are useful indicators of the effects of deer.

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Harvest‐based Bayesian estimation of sika deer populations using state‐space models

Cited by 46 publications

References 50 publications

Culling Versus Density Effects in Management of a Deer Population

Culling Versus Density Effects in Management of a Deer Population

Adaptive management of sika deer populations in Hokkaido, Japan: theory and practice

Effects of deer abundance on broad-leaf tree seedling establishment in the understory of Abies sachalinensis plantations

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