野生生物と社会
Online ISSN : 2424-2365
Print ISSN : 2424-0877
ISSN-L : 2424-0877
3 巻 , 2 号
選択された号の論文の4件中1~4を表示しています
原著
  • Kazumi Shionosaki, Shigeki Sasaki, Fumio Yamada, Shozo Shibata
    2016 年 3 巻 2 号 p. 1-13
    発行日: 2016年
    公開日: 2017/06/17
    ジャーナル フリー

     To protect endangered endemic species from predation by domestic cats (Felis silvestris catus) in Amami-Ohshima Island, Japan, the five local governments on the island issued a regulation in October 2011 on the proper raising and management of domestic cats. We studied the changes in owned and unowned free-roaming cats' activities in a mountain forest (2 km2 in size), near residential areas in Amami City, following the enforcement of the regulation, specifically the prohibition on cat feeding. A camera-trapping method was used to monitor cat activities for six months, prior to the regulation being in force, (2010-2011), and for seven months following the regulations' enforcement (2011-2012).

     In response to food availability following the regulation enforcement, the number of unowned cats decreased by almost half, and their activities shifted to nocturnal. Moreover, both owned cats and unowned free-roaming cats tended to utilize the forest interior more than other areas (forest roadside and forest edge adjacent to the residential areas).

     Although the goal of the regulation is the protection of endemic species against domestic cat predation, the results of the present study indicate that the regulation will increase rather than decrease predation risk to endemic species. Therefore, even though the prohibition on feeding can be effective in reducing free-roaming cat reproduction in the long-term, more direct approaches, such as the removal of free-roaming cats from the endemic species' habitats, might be more effective in the short-term, as well as educating cat owners on the risks owned free-roaming cats pose to endemic species.

  • 立脇 隆文, 小池 文人
    2016 年 3 巻 2 号 p. 15-28
    発行日: 2016年
    公開日: 2017/06/17
    ジャーナル フリー

     Collecting and accumulating records of wildlife-vehicle collisions are useful for two purposes: to improve road safety, and to monitor the density of wildlife. Such records in Japan are obtained largely from roadkill collected by road managers or cleaners from local or national governments; however, little is known about the records within municipalities. The objective of this study was to provide an overview of roadkill records within municipalities in Japan. Particularly, this study aimed to reveal: the proportion of municipalities that have records of roadkill; the bureau that is mainly responsible for these records within municipalities; how the records are used by municipalities; and what information is usually available in these records. A questionnaire was sent to 650 municipalities across Japan, and was returned by 503 (77.4%) of the municipalities. Of the municipalities that answered the questionnaire, 68.6% recorded roadkill incidents in some way. The answers showed that in the majority of municipalities, cleaners within the municipality recorded roadkill, and road managers did not. About 90% of the records were discarded after 5 years had passed since they were recorded. The municipalities sometimes used the records for accounts of removing roadkill, or to reply to inquiries from citizens or prefectural offices, but rarely used them for preventing wildlife-vehicle collisions. Of the municipalities that answered the questionnaire, 50.1% collected roadkill not only from the municipal roads, but also from the prefectural or national roads, which municipalities have no responsibility to manage. The person removing the roadkill was usually the one to identify what species it belonged to. Each municipality recorded roadkill differently, as either a hand written note or as an electronic file in Microsoft Excel. The information available about roadkill in the majority of municipalities were month, location, and the species or taxa of animal removed. However, only 39.4% of the municipalities recorded all three characteristics. Based on these results, we suggest there should be a standardized system to collect roadkill records in Japanese municipalities, which could be used to improve road safety and monitor the density of local wildlife.

  • 角田 裕志, 浦野 隆弘, 大平 充
    2016 年 3 巻 2 号 p. 29-39
    発行日: 2016年
    公開日: 2017/06/17
    ジャーナル フリー

     Understanding the growth, fecundity and survival, as well as population density, is the basic knowledge for conserving threatened species. By counting the annuli on the scales, we estimated the age of the threatened piscivorous cyprinid fish, Amur three-lips (Opsariichthys uncirostris uncirostris), in Lake Biwa located in central Japan. A total of 169 individuals were caught, including 111 males, 56 females, and two for which the sex was undetermined. To estimate the growth of the three-lips, we used data from 56 males and 28 females caught during a single reproductive season (late May to early August 2013). The estimated maximum standard lengths and growth coefficients were 274.20 mm and 0.25 for males and 269.23 mm and 0.22 for females, respectively. The growth curves of the standard lengths were expressed using von Bertalanffy's growth equation by using the estimated variables. We compared our growth equations to those in a previous study conducted in the 1970's. The results indicated that the relative growth rates of the three-lips decreased in 1- and 2-year-old fishes. In addition, we found that fishes that were 3-years and older were shorter in average length than those in the previous study. We suggest that the current decline in growth rate of the three-lips is associated with the decline of fish prey resources because of changes in the habitat driven by human activities as well as the invasion of competitive exotic fishes, such as the largemouth bass (Micropterus salmoides), over the recent past decades.

報告
  • 寺尾 愛也, 日野 貴文, 鈴木 正嗣, 近藤 誠司, 吉田 剛司
    2016 年 3 巻 2 号 p. 41-50
    発行日: 2016年
    公開日: 2017/06/17
    ジャーナル フリー

     In Japan, the use of firearms to culling in areas surrounding the main road would be an effective option to control overabundant deer. This culling practice is linked to the laws and regulations regarding road and traffic; however, wildlife managers lack knowledge of these laws and regulations. We have identified Japanese regulations and conditions, and have focused on problems and prospects of the existing laws on sharpshooting, which was practiced at the National Route 453 in Shikotsu, Hokkaido, as a model case. Under these laws and regulations, strict safety control by blocking traffic and attending to public interests for culling is required in order to engage in culling around the road. However, the Road Law and Road Traffic Law do not specifically support road usage for culling intended for wildlife population control. Consequently, those laws require a viewpoint of wildlife management to solve conflicts that occur in and around the road.

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