Fifty-seven female sika deer ( Cervus nippon yesoensis ), captured at the wintering area in the Shiranuka Hills in eastern Hokkaido, Japan, were radio-tracked during 1997-2001 to examine the factors affecting seasonal migration at the individual-landscape level. Ten of the 57 deers migrated between low-altitude summer home ranges and intermediate-altitude winter home ranges (the upward migrants). Twenty-nine migrated between high-altitude summer home ranges and intermediate-altitude winter home ranges (the downward migrants). Twelve used the intermediate-altitude home ranges all year round (the nonmigrants). The remaining six were unknown. The summer home ranges of deer were widely scattered over an area of 5734 km 2 . Migration distances ranged between 7.2 and 101.7 km. Deer showed high site fidelities to their seasonal home ranges. The upward migrants wintered in areas of less snow, higher quality of bamboo grass, and more coniferous cover than their summer home ranges. The downward migrants wintered in areas of less snow, higher quality of bamboo grass, higher winter temperature, and more southern slopes, but less coniferous cover than their summer home ranges. The non-migrants used yearround ranges with little snow, high quality of bamboo grass, and sufficient coniferous cover. We suggest that snow cover and bamboo grass are the factors affecting seasonal migration of the population and that coniferous cover is another factor for the upward migration.

The role of cell membrane dynamics in cell migration is unclear. To examine whether total cell surface area changes are required for cell migration, Dictyostelium cells were flattened by agar-overlay. Scanning electron microscopy demonstrated that flattened migrating cells have no membrane reservoirs such as projections and membrane folds. Similarly, optical sectioning fluorescence microscopy showed that the cell surface area does not change during migration. Interestingly, staining of the cell membrane with a fluorescent lipid analogue demonstrated that the turnover rate of cell membrane is closely related to the cell migration velocity. Next, to clarify the mechanism of cell membrane circulation, local photobleaching was separately performed on the dorsal and ventral cell membranes of rapidly moving cells. The bleached zones on both sides moved rearward relative to the cell. Thus, the cell membrane moves in a fountain-like fashion, accompanied by a high membrane turnover rate and actively contributing to cell migration.

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.

We have estimated the number of sika deer, Cervus nippon, in Hokkaido, Japan, with the aim of developing a management program that will reduce the level of agricultural damage caused by these deer. A population index that is defined by the population divided by the population of 1993 is first estimated from the data obtained during a spotlight survey. A generalized linear mixed model (GLMM) with corner point constraints is used in this estimation. We then estimate the population from the index by evaluating the response of index to the known amount of harvest, including hunting. A stage‐structured model is used in this harvest‐based estimation. It is well‐known that estimates of indices suffer from large observation errors when the probability of the observation fluctuates widely; therefore, we apply state‐space modeling to the harvest‐based estimation to remove the observation errors. We propose the use of Bayesian estimation with uniform prior‐distributions as an approximation of the maximum likelihood estimation, without permitting an arbitrary assumption that the parameters fluctuate following prior‐distributions. We are able to demonstrate that the harvest‐based Bayesian estimation is effective in reducing the observation errors in sika deer populations, but the stage‐structured model requires many demographic parameters to be known prior to running the analyses. These parameters cannot be estimated from the observed time‐series of the index if there is insufficient data. We then construct a univariate model by simplifying the stage‐structured model and show that the simplified model yields estimates that are nearly identical to those obtained from the stage‐structured model. This simplification of the model simultaneously clarifies which parameter is important in estimating the population.

Sika deer Cervus nippon in Hokkaido, Japan, have recovered from a popula tion bottleneck about 120 years ago and their distribution has expanded rapid ly in the last three decades. We tracked 53 radio-collared female sika deer, and obtained 4,430 locations during the 25-month study period from April 1997 to April 1999. We examined the seasonal distribution of female sika deer in rela tion to spatial landscape features (snow depth, vegetation, bamboo grass and roads) with a logistic regression model using a geographic information system database. We presented a population-landscape scale evaluation of sika deer habitat for summer and winter within the telemetry study area (TSA) using resource selection functions. We then extrapolated the model to the rest of east ern Hokkaido to discuss the seasonal migration for an expanding population. Most radio-collared sika deer (71%) moved between high-elevation summer and low-elevation winter ranges, whereas some (29%) moved between low-e l e v a t i o n summer and similar or high-elevation winter ranges. During winter, sika deer selected middle elevation habitats (200-400 m a.s.l.) with both a rela tively low snow depth and the presence of coniferous and mixed forests. On the other hand, sika deer were widely distributed regardless of elevation during sum mer, although they were further from roads and less often in agricultural lands. Within the TSA, the suitable habitat was very limited during winter compared with during summer. Although migration from summer to winter ranges may depend on the abundance and distribution of suitable winter habitat at a land scape scale, migration from winter to summer ranges could not be explained from this study. Our approach is useful for understanding the relationships among seasonal habitat selection, seasonal migration and the expansion of the popu lation.