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Cervid populations introduced to favorable habitats in confinement often increase excessively without predators and hunting. Overabundant deer populations impact the ecosystems and may cause damages to agriculture and forestry. Long‐term count data on the changes in a deer population is essential to understand the relationship between the population dynamics and the natural vegetation. The introduced sika deer (Cervus nippon Temminck, 1836) population without predators on Nakanoshima Island, Hokkaido, Japan, showed repeated irruptions and declines with mass mortality and irregular culling between 1980s and 2000s. The overabundant deer significantly altered the natural vegetation, and density‐dependent changes in population parameters such as body size and reproduction were observed. Here, we present the drive count and culling data to examine the population dynamics during 1980–2023. Deer were counted by 20–30 walking drivers and 2–3 observers on boats once per year in February or March. The number of counted deer rapidly increased from the original three introduced around 1960 to >270 deer (the first peak) in two decades and decreased by half due to starvation and the first culling. Thereafter, the number of counted deer continued to increase with a lower growth rate, reached a higher peak (>400, the second peak) than the first irruption in two decades, and decreased again by half due to starvation and the second culling. Although the number of counted deer increased again up to >300 in several years, it decreased and was maintained at around 100 deer with the annual culling program since 2012. The complete data set for this abstract published in the Data Article section of the journal is available in electronic format in MetaCat in JaLTER at http://db.cger.nies.go.jp/JaLTER/metacat/metacat/ERDP-2024-06.1/jalter-en. [ABSTRACT FROM AUTHOR]

Investigates the effect of the population structure of ninespine stickleback on gene flow and genetic diversity in Hokkaido, Japan. Importance of genetic diversity in evolutionary biology; Factors that may influence genetic diversity; Frequencies of mitochondrial DNA control region sequence haplotypes of stickleback.

Adaptive hunting management is commonly used for controlling the populations of overabundant large herbivores; however, induced behavioural changes can make the effective control of target populations difficult. However, few studies have compared the impact of different levels of hunting intensities on the activity patterns of ungulates before, during, and after a culling program. We investigated how different culling intensities affect the activity patterns of sika deer on Nakanoshima Island in Lake Toya, Hokkaido, Japan using camera-trap surveys comparing the period of treatment before, during, and after a culling program. We used the number of deer photographed per hour per camera as an index of activity. Sika deer showed consistent crepuscular activity patterns (i.e., dawn and dusk) during spring–summer and trimodal activity patterns (i.e., dawn, dusk, and midnight) in autumn throughout the study period. In response to increased culling intensity, the activity peaks shifted slightly towards the night. The shift towards nocturnal activity persisted during post-culling period. Understanding the changes in activity patterns in response to culling intensity could be used to facilitate population control and assist in establishing a night shooting program. Thus, wildlife managers should consider night shooting once hunting during day time has shifted the normal diurnal activity of deer to nocturnal activity. [ABSTRACT FROM AUTHOR]