On two beaches (Ubu and Sazare) of southern Iriomote Island, Ryukyu Archipelago, southern Japan, wild boars have dug up sea turtle nests and preyed on their eggs. In 2010, camera trapping, field surveys, and direct observations were conducted to investigate wild boar behavior and predation. In total, there were 34 and 60 sea turtle nests on Ubu and Sazare Beaches, respectively. All 34 nests on Ubu Beach and 26 (43%) of the 60 nests on Sazare Beach were predated upon. Of the 30 observations of wild boars, 17 (57%) dug up sea turtle body pits. Wild boar tracks and sea turtle nests were found near vegetation, and seasonal variation in the number of wild boars on Ubu Beach was similar to the number of sea turtle nests. Our observations suggest that wild boars are attracted to beaches during the sea turtle nesting season to prey on turtle eggs.
Understanding the relationship between habitat selection by Asiatic black bear (Ursus thibetanus) and annual fluctuations in hard mast productivity is important in conservation and management. However, a detailed investigation regarding this relationship is still lacking. Previous studies have indicated that the vegetation map prepared by the Ministry of Environment has not always been useful to evaluate habitat selection by bears. In this study, we assessed the vegetation of the core area used by bear using a field survey and a high-resolution vegetation map. Then, we compared habitat selection in autumn between a poor and a moderate mast year. Results demonstrated the bears selected Quercus crispula forest in the moderate mast year. The field survey revealed Q. crispula was dominant in the core area. However, selective use of the vegetation was not detected in the poor mast year. In addition, there were other hard mast producing species in the core area in the poor mast year, while Q. crispula was only found in the moderate mast year. Thus, bears depended on Q. crispula, which was dominant in the study area, as their main resource in autumn. They also used alternative hard mast species, indicating flexibility in response to hard mast productivity fluctuation.
The roosting ecology of Murina ussuriensis were examined using dead-leaf Mallotus japonicus traps and radio transmitters in warm-temperate forests in the Kyushu district, Japan. Recapture rate at natal sites after the first year averaged 13% for yearling males, and 16% for yearling females. Adults roosted individually in the active season, expect for females during the breeding season from June to August. Adult males roosted in the lower and middle layers of forests from May to October, and frequently switched their day-roosts. Adult females formed maternity colonies in the middle layer of the forest, and frequently changed their maternity roosts. After nursing, adult females roosted individually in the lower layers. In the adult stage, 44% and 42% of recaptured male and female bats, respectively, remained at the capture location. In the case of movement, the average shifting distances were 116 m in males, and 209 m in females. Some of the young bats weaned in summer reached sexual maturity in autumn of the same year. The oldest age determined for M. ussuriensis was four years in males and 4.5 years in females.
We investigated the nest use of Japanese squirrels (Sciurus lis) via radio-tracking in a suburban forest of Morioka City, Iwate Prefecture, northeastern Japan, from April to December 2010, July to October 2012 and May 2013 to July 2014. Squirrels frequently used dreys on evergreen trees all year round. Dreys were widely used in green-leaved seasons, and cavities were comparably used in both seasons. In addition, home range and nest site movement distance (straight line distance between nest locations prior to and after nest changes) were larger for males than for females. Nest site movement distance (mean ± SD) for females was 68 ± 42 m in the green-leaved season, and 82 ± 42 m in the defoliated season. That of males was 115 ± 59 m in the green-leaved season, and 135 ± 71 m in the defoliated season. The average distance of the closest approach from a nest to a walnut tree was 37.4 ± 33.3 m for males, and 30.5 ± 22.2 m for females. Squirrel movement appeared to reduce predator risk while efficiently using food resources, suggesting seasonal food use adaptation.
Two populations of the long-legged whiskered bat, Myotis frater, roosting in artificial structures, were studied during 21 years capture-mark-recapture at Fukase, Hakusan City, Ishikawa Prefecture and Suzuran, Matsumoto City, Nagano Prefecture, respectively. The majority of the individuals found were adult and sub-adult males. Yearly survival rates estimated by recapture duration decay plotting were 0.871 and 0.863, and longevities averaged 7.3 and 6.8 years for Fukase and Suzuran populations, respectively. The maximum longevity records were 14 and 17 years for Fukase and Suzuran, respectively. Total numbers of males were estimated as 26.4 and 70.2, and the mean population sizes of males were 9.1 and 22.7 for Fukase and Suzuran, respectively.
To clarify suitable bait to attract wild sika deer (Cervus nippon), we surveyed deer preferences for selected baits among 4 type baits (alfalfa hay, timothy hay, alfalfa hay cube, and formula feed) in an experimental forest in Yamanashi Forest Research Institute (N35°33′32.62″, E138°26′27.58″) over 4 seasons with motion-triggered camera. Alfalfa hay was most preferred regardless of season, and the preference order was formula feed, alfalfa hay cube, and timothy hay. Timothy hay was rarely eaten by sika deer. Formula feed was eaten by other animals. In conclusion, we suggest that alfalfa hay is particularly suitable bait to attract sika deer.
To elucidate the past distribution of an extinct local population of the Eurasian otter (Lutra lutra), we conducted a literature review and interview survey on the Goto Islands, Nagasaki Prefecture, western Japan. We found nine records in public libraries, and eight witnesses among local elderly persons. The evidence strongly suggest that otters once lived in this area. The latest literal record of the otter was in the 1950s, whereas the latest eyewitness was in 1981. The result implies that the extinction of the otter population from Goto Islands was largely due to overhunting and poaching after the ban in 1928, while habitat loss seemed to act as an additional factor. We expect that further studies can reveal physical evidence of the otter (e.g. photos and furs) as well as accumulating its records in this area.
Raccoon dogs (Nyctereutes procyonoides) may use the same setts originally dug by Japanese badgers (Meles anakuma). When ecological niches of two sympatric species overlap, competitive exclusion is possible. Thus, we expected that these species have altered their appearance timing (period in a year and/or time zone in a day). In this study, three infrared sensor cameras were set up near setts in Ohanna-yama, Ohno, Uenohara, Yamanashi Prefecture that had previously been inhabited by both badgers and raccoon dogs, and their activities were monitored from late June to mid December 2014. Japanese badgers and raccoon dogs showed altered periods and time of appearance near the setts. This finding suggests that the two species used the same setts but at different times. Compared to Japanese badgers, raccoon dogs were spotted more frequently near the setts and the duration and ratio of their exploratory behavior were longer, suggesting that Japanese badgers possibly spent more time inside the setts than did raccoon dogs. These results suggest that raccoon dogs shared the same setts as Japanese badgers, but avoided accidental encounters with them using their exploratory behavior, based on their sense of smell.
The use of roosts by Ussurian tube-nosed bats (Murina ussuriensis) was studied using artificial dead leaves made of hemp. From late April 2015 to late November 2015, the leaves were placed on branches over the forest floor and on those near tree crowns. A group of females were continuously observed from late April until late June, corresponding to the period from pregnancy to nursing, and maternity and nursery colonies including infants in the artificial roosts on the branches were confirmed during June. The number of adults and infants in the roosts changed with each observation. In addition, maternity and nursery colonies frequently changed roosts. The present study is the first to demonstrate the formation of maternity and nursery colonies of M. ussuriensis in artificial roosts. Further, a few instances of the use of artificial roosts by a single male or female were observed from July to late November. The survey method used in this study can be a useful technique to study the reproductive ecology of this species, which cannot be easily observed.
In this study, we analyzed annual and seasonal changes in the numbers of spotted seals (Phoca largha) hauled out in the area around Bakkai and Yagishiri in the Japan Sea from 2003 to 2009, for the first time. The number of animals observed tended to increase over the years at both sites, but the increment was bigger in Bakkai than Yagishiri. This is thought to be due to spatial differences among the haul-out sites, with the former location having a larger area. In addition, seasonal changes in the numbers of seals were different; there was a single peak in Bakkai observed in winter, while Yagishiri had two peaks, one during winter and the other in spring. These seasonal changes are thought to be related to changes in the distribution of sea-ice in the Okhotsk Sea. Because adult seals are known to migrate to sea-ice areas to breed after winter, the seals counted in Yagishiri during spring reflect the number of sub-adults staying in this region.
The original spread of coypu, Myocastor coypus, in Japan has usually been discussed in the context of military fur use during World War II. The escape and spread of the species is popularly thought to have originated from the destruction of militarism in the country.
In this paper, we attempted to reveal the details and circumstances of the second coypu breeding boom after WWII based on the primary resources collected by Dr. Kyoji Kondo and other documents and literature. In the latter half of the 1940’s shortly after the war, a food production stabilization five-year plan resulting in the promotion of livestock raising, was formulated in answer to the national voice for the increase of food protein production. The second coypu breeding boom resulted as a part of this plan.
The starting point of the second coypu breeding boom was the proposal by Drs. Hidemichi Oka and Haruo Takashima, who advocated the effective use of coypu raised for meat. Coypu farming was adopted as the first choice of relief against severe famine because of how easily the animals can be raised.
In short, the second culture boom of coypu in Japan, which is the greatest cause of its naturalization in Japan, originated from the farming of this species as a national policy, part of the economic revival action plan after WWII.
In this study, we surveyed the range expansion of invasive tree squirrels (Callosciurus erythraeus and C. finlaysonii) in Hamamatsu, Shizuoka Prefecture, Japan. Although previously conceived that the northern limit of the range was south of a highway thought to act as a barrier that slowed range expansion, we here suggest that invasive squirrels have already expanded their range across the highway and into a green park located approximately 2 km north and away from the highway. The distance from the range–forefront that we suggested to the mountainous area is only 7 km, and some small woodlots appear between the areas. We fear that invasive tree squirrels could easily expand their range to those woodlots and, in the near future, further into the mountainous area. Developing a contingency plan to discourage squirrel range expansion is essential before the range expands further, because eradicating the squirrels would likely be difficult in such a mountainous area.
We report a new sighting record of Sus scrofa on Nozaki Island, Goto Islands, Nagasaki Prefecture, and the following rapid expansion on the Island. The first individual was visually recorded in the deer survey of 2010. On following deer survey of 2011, 2012 and 2014, the number of sighting points and food remains gradually increased and expanded to cover the whole island. In the latest survey, a total of 19 encounters of wild boars were recorded during three days in December 2014. The rapid increase of the wild boar population on Nozaki Island may have been caused by repeated reproduction on the island because subadults were confirmed over several years. In the near future, the number of wild boars on the Goto Islands will increase by reproduction and movement among islands over the sea.
In most Northern Hemisphere temperate countries, overabundant deer populations are recognized to have profound effects on forest vegetation and soil. Forests in these countries have been damaged by browsing and bark peeling, and shifts in species composition and regeneration failures in damaged forests have been reported from many sites. Agricultural and forest damage caused by sika deer (Cervus nippon) has recently become more urgent in Japan. For the sake of healthy forests both today and in the future, deer populations should be managed to a moderate density level. However, it seems to be extremely difficult to control overabundant sika deer populations using traditional approaches. In this symposium, we focused on comprehensive forest management in deer habitat and localized management as a relatively new, scientific management strategy to control deer populations. We had four speakers who have been studying deer and forest management in the USA, UK, and Japan. We discussed possible new approaches based on the scientific management of deer, and forest management approaches currently in use in Japan.
A round table session was held in the Vth International Wildlife Management Congress to make a proposal for the sustainable management of deer and forests in Japan. Three cases were reported; the Akaya Project aims to conserve biodiversity through the maintenance of low deer density; Shimukappu is a game area aiming to establish sustainable resource management through the municipal government; Mitsui’s forests are company-owned and deer management is considered important to control damage to forests and neighboring farm fields. In Japan, the roles and responsibilities of land owners, municipalities and prefectural and national governments are not clear for wildlife management. Key issues include (1) role-sharing and cooperation among stakeholders, (2) securing sufficient personnel who perform to cull deer, and (3) ensuring financial resources. Municipalities should play a leading role to cope with a broad range of problems caused by deer moving around a large area, and cooperating with forest owners and prefectural and national governments with distinct responsibilities. Municipalities need leaders with specialized skills, and prefectural and national governments are expected to foster human resources and promote cooperation among municipalities. Forest owners can provide favorable hunting fields. Stable public funds should be invested to evaluate the multiple values of forests maintained by deer management.
In this symposium, we discussed the current status of ungulate management in East Asian countries where ungulates are overabundant. We also discussed future strategies to control ungulate populations by learning precedents from Europe. Hunting is considered to be one important factor for wildlife management systems in European countries. However, problems have become apparent when ungulate population control depends on recreational hunters, because recreational hunters tend to be more interested in their harvest than issues relating to overabundant populations. East Asian countries should recognize this fact as precedence for failure.
Human-macaques conflicts have become major concerns in many countries. Japanese macaques (Macaca fuscata) are considered to be major agricultural pests in most rural areas in Japan, where studies and management practices to alleviate crop damage have been carried out. Human population has been declining and aging in Japan, and so the development of an effective management methodology and restructuring of the current management system will be needed in the future. In this symposium, we introduced the present situation and discussed future prospects of Japanese macaque management in an aging and depopulating society. Although it appears to be difficult to reduce conflicts because of their excellent agility and learning capacity, two different approaches have been proven to be effective in Japan. One is community-based damage management. This approach has been demonstrated to enhance its effectiveness by including cooperation with and among local people. The other is planned population control in managed troops. This approach requires adopting the appropriate capture method based on the scientific data about the population and characteristics of the troop. Recently some local governments have initiated planned population control and gathered data on its effectiveness. Their results provide new insights into macaque management. Additionally, we need to discuss integrated methodologies combining these two approaches. It is also necessary to consider long-term conservation of macaque populations as a part of management.
We held an invasive species management symposium and a roundtable supported by the Ministry of the Environment of the Government of Japan in the International Wildlife Management Conference (IWMC2015) on July 28th, 2015 at the mid-term towards the targeted year 2020 of Aichi Biodiversity Target 9. In the symposium, we had two talks presenting international perspectives on patterns and trends of biological invasions in prioritizing pathways and species to improve prevention and enhance effective mitigation of impacts, and on international regulatory frameworks on invasive alien species, pests and diseases. From the Japan side, a talk on addressing invasive alien species in Japan, including progress and challenges, and another talk on towards achievement of Aichi Biodiversity Target 9: Measures to address invasive alien species in Japan, were presented. We discussed that a collaborative approach of the wider stakeholders, including governments and scientists, should be further enhanced under the different circumstances of countries to address the growing issue of invasive alien species and on the importance of public awareness for the Aichi Biodiversity Target 9.
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