Ibaraki Nature Museum


Ibaraki Nature Museum

Time filter
Source Type

Saitoh K.,Japan National Research Institute of Fisheries And Environment of Inland Sea | Suzuki N.,Natural History Museum and Institute | Ozaki M.,Chiba Prefectural Fisheries Research Center | Ishii K.,Ibaraki Prefectural Government | And 4 more authors.
Nature Conservation | Year: 2017

Overuse of natural resources by humans is a major threat to biodiversity. Overuse often involves species of economic or esthetic value, and fish are a typical example for a group that is exploited both for economic reasons (for human consumption) and for esthetic reasons (e.g. by aquarists). Pseudorhodeus tanago (Tanaka, 1909) (formerly known as Tanakia tanago) is a small colorful but legally protected (fishing, keeping and transfer are banned) bitterling fish distributed around Tokyo, Japan. Whereas it is critically endangered and more and more habitat loss has occurred, at least four stocks have been newly found during the last decade. To explore whether emergence of these newly found habitats is a consequence of incomplete survey, we genotyped mitochondrial cytochrome b sequence of P. tanago from 17 localities and an illegal home aquarium. Populations known by the past extensive survey (13 localities) showed geographically structured population genetic characteristics. Population-specific haplotypes were common indicating past divergence and bottleneck events. Four (north, {center + west}, south-1, south-2) or five (north, center, west, south-1, south-2) geographic groups were detectable as for these known localities. On the other hand, newly found stocks were polymorphic and showed identical haplotypes from distant known localities. If we assume historical basis of distribution and genetic characteristics of these newly found stocks, it must be a series of unlikely geological events and haplotype sorting. We discuss potential issues posed by these questionable stocks.

Furusaka S.,Tokyo University of Agriculture and Technology | Kozakai C.,Kanagawa Prefectural Museum of Natural History | Kozakai C.,Japan National Agriculture and Food Research Organization | Nemoto Y.,Tokyo University of Agriculture and Technology | And 5 more authors.
ZooKeys | Year: 2017

The present study aimed to investigate the nutritional aspects of the bear diet quantitatively, in order to understand plant food selection in spring. Bears were observed directly from April to July in 2013 and 2014, to visually recognize plant species consumed by bears, and to describe the foraging period in the Ashio-Nikko Mountains, central Japan. Leaves were collected from eight dominant tree species, regardless of whether bears fed on them in spring, and their key nutritional components analyzed: crude protein (CP), neutral detergent fiber (NDF), and total energy. Bears tended to consume fresh leaves of specific species in May, and nutritional analysis revealed that these leaves had higher CP and lower NDF than other non-food leaves. However, CP in consumed leaves gradually decreased, and NDF increased from May to July, when the bears’ food item preference changed from plant materials to ants. Bears may consume tree leaves with high CP and low NDF after hibernation to rebuild muscle mass. © Shino Furusaka et al.

Inoue T.,Hokkaido University | Kaneko Y.,Tokyo University of Agriculture and Technology | Yamazaki K.,Ibaraki Nature Museum | Anezaki T.,Gunma Museum of Natural History | And 7 more authors.
Conservation Genetics | Year: 2012

The masked palm civet Paguma larvata (Carnivora: Viverridae) in Japan has been phylogeographically considered an introduced species from Taiwan. To reveal the population structures and relationships among the P. larvata populations in Japan, seven compound microsatellite loci were isolated from the genome and genotyped for 287 individuals collected from the field. STRUCTURE analysis and factorial correspondence analysis of genotyping data revealed that animals from Japan were divided into four genetic clusters. Geographic distribution of the genetic clusters partly referred to sampling areas, indicating multiple introductions into distinct areas of Japan or independent founding events leading to the generation of different genetic clusters within introduced populations in Japan. The large genetic differentiation of populations in the Shikoku District from those in other areas within Japan suggests that there were at least two introduction routes into Japan, and a possibility that some founders from areas other than Taiwan were also involved in the introduction into Japan. The genetic variation within Japanese populations were not markedly reduced compared with that of Taiwan. The results indicated that the Japanese populations of P. larvata could have retained moderate genetic diversity during founding events, because of multiple introductions, or a large number or high genetic diversity of founders. Although some individuals in Japan showed a sign of admixture between different clusters, there is no evidence that such an admixture markedly increased the genetic diversity within Japanese populations. © 2012 Springer Science+Business Media B.V.

Tanabe K.,University of Tokyo | Misaki A.,Kitakyushu Museum of Natural History and Human History | Landman N.H.,American Museum of Natural History | Kato T.,Ibaraki Nature Museum
Lethaia | Year: 2013

The jaw apparatuses of two species of Late Cretaceous Phylloceratina (Ammonoidea), Hypophylloceras subramosum and Phyllopachyceras ezoensis, are described on the basis of well-preserved in situ material from Hokkaido, Japan. Gross morphological and X-ray CT observations reveal that the upper and lower jaws of the two species are essentially similar in their overall structure. Their upper jaws consist of a shorter outer lamella and a pair of larger, wing-like inner lamellae that become narrower and join together in the anterior portion, as in those of other ammonoids. The upper jaws of the two phylloceratid species are, however, distinguishable from those of other known ammonoids by the presence of a thick, arrowhead-shaped calcified rostral tip. The lower jaws of the two species consist of a short, reduced inner lamella and a large, gently convex outer lamella covered with a thin calcareous layer, the features of which are common with the rhynchaptychus-type lower jaws of the Cretaceous Lytoceratina. In the presence of a sharply pointed, thick calcareous tip on upper and lower jaws, the jaw apparatuses of the Phylloceratina resemble those of modern and fossil nautilids, suggesting that they were developed to serve a scavenging predatory feeding habit in deeper marine environments. This and other studies demonstrate that at least some Mesozoic rhyncholites and conchorhynchs are attributable to the Phylloceratina and Lytoceratina. © 2013 The Lethaia Foundation.

Koike S.,Tokyo University of Agriculture and Technology | Morimoto H.,Tokyo University of Agriculture and Technology | Kozakai C.,Tokyo University of Agriculture and Technology | Arimoto I.,Tokyo University of Agriculture and Technology | And 3 more authors.
Acta Oecologica | Year: 2012

We studied the effects of dung beetles on the fates of endozoochorous seeds of five species (Prunus jamasakura, Prunus verecunda, Prunus grayana, Swida controversa, and Vitis coignetiae) in a temperate deciduous forest in Japan during 2004-2006. In field experiments using dung of the Asiatic black bear (Ursus thibetanus), we investigated the depths that dung beetles (Onthophagus atripennis, Onthophagus lenzii, and Phelotrupes auratus) buried seeds (4.8-6.8 mm diameter) and plastic markers (2 or 5 mm diameter), the levels of predation on buried and unburied seeds, and germination rates of seeds buried to different depths. All three species buried the 2-mm markers, but only P. auratus buried the seeds and 5-mm markers. There were seasonal differences in mean seed burial rates (range, 27-51%) and depths (range, 1-27 mm). Significantly more seeds were buried in June, July, and September than in August or October, and the mean burial depth was significantly deeper in June and July. Most seeds and markers were buried to a 3-6 cm depth. Germination of seeds that were positioned at depths of 1-4 cm was significantly greater than that of seeds left on the surface or buried at greater depths. Buried seeds were less likely to disappear than seeds at the surface, which may reflect differential predation. These results suggested that dung beetles, especially P. auratus, acted as a secondary seed disperser that affected the survival and distribution of seeds dispersed by a frugivore. © 2012 Elsevier Masson SAS.

Koike S.,Tokyo University of Agriculture and Technology | Morimoto H.,Tokyo University of Agriculture and Technology | Kozakai C.,Tokyo University of Agriculture and Technology | Arimoto I.,Tokyo University of Agriculture and Technology | And 4 more authors.
Wildlife Biology | Year: 2012

We investigated the fate of seeds of five tree species hill cherry Prunus jamasakura, Korean hill cherry P. verecunda, Japanese bird cherry P. grayana, giant dogwood Swida controversa and crimson glory vine Vitis coignetiae in the faeces of the Asiatic black bear Ursus thibetanus in a temperate forest in central Japan. Clarifying the fate of seeds dispersed by endozoochorous seed dispersers will enhance assessments of their roles as primary seed dispersers. We established several experimental treatments in the field. Each faeces sample was covered by cages with different mesh sizes which limited accessibility by animals (NM: no mesh, SM: 1 mm mesh and MM: 10 mm mesh). We examined whether seed removal varied among tree species and between mesh-size treatments from 2004 to 2007 (N = 625 samples). We set up an automatic camera trap 1.5 m above the ground at all NM treatments. In the NM treatments, the number of seeds of all tree species decreased immediately after the faeces were set. In June of the following year, < 1% of the seeds from any species remained in the vicinity of the faeces. However, we found 3.0-13.2% intact seeds of all species in the soil below the faeces, as well as within a 10-m radius around the faeces. In the NM treatments, most seed removals were observed within four days after the faeces were set. For all tree species in the MM treatment, most of the seeds were present on the surface of the soil, and 1-2% of the seeds germinated at the location where faeces were set. In the SM treatment, none of the seeds from any of the tree species disappeared and germinated. We took a total of 415 photographs at the NM sites, 97.8% of which were of rodents either holding or eating seeds. Many of the seeds contained in the bear faeces were removed and eaten by rodents. However, 2.1-5.1% of the seeds survived and germinated, which implies that rodents may also act as secondary seed dispersers. © 2012 Wildlife Biology, NKV.

Koike S.,Tokyo University of Agriculture and Technology | Nakashita R.,Japan Forestry and Forest Products Research Institute | Kozakai C.,Kanagawa Prefectural Museum of Natural History | Nakajima A.,Tokyo University of Agriculture and Technology | And 3 more authors.
European Journal of Wildlife Research | Year: 2016

Measures of δ13C and δ15N in tissues of Asiatic black bears (Ursus thibetanus) can be useful in helping researchers identify nuisance bears and in determining whether a specific bear might be consuming anthropogenic food such as garbage and corn. However, the δ13C and δ15N values of native foods vary across the bear’s range. The purposes of this study were to characterize the stable isotope ratios of bear tissues and potential non-anthropogenic food items and compare that characterization to other studies and an independent analysis of bear food habits. We collected hair from bears in the Ashio–Nikko Mountains (ANM) that, based on capture location and radiotelemetry data, were consuming non-anthropogenic food. We found that the δ13C ratios of bear hair from the ANM were significantly higher than those of bears sampled in another area in central Japan where bears were also eating native food. Bears in the ANM consumed large amounts of ants in summer. Ants in this part of the ANM have relatively higher δ13C value than ants from other areas. Miscanthus sinensis, a C4 plant with a high δ13C value close to that of corn , is abundant in parts of the ANM. We also found that the δ13C of herbivorous insects that may not be consumed by bears also had high δ13C content. From these analyses, the δ13C in bear hair in the ANM was high because bears consume ants in summer and because ants in turn may consume herbivorous insects that feed on C4 plants. Past studies indicate that high δ13C values in bear hair may be used to identify nuisance individuals that damage corn on farms. However, our results showed that bears consuming natural foods may also have high δ13C levels in some regions. Thus, identification of nuisance bears based on isotope data should account for variation in the isotopic signatures of non-anthropogenic food items and should identify and use locally appropriate isotopic end members. © 2015, Springer-Verlag Berlin Heidelberg.

Koike S.,Tokyo University of Agriculture and Technology | Kozakai C.,Tokyo University of Agriculture and Technology | Nemoto Y.,Tokyo University of Agriculture and Technology | Masaki T.,Japan Forestry and Forest Products Research Institute | And 5 more authors.
Mammal Study | Year: 2012

We studied the relationships between movement and foraging habits of the Asiatic black bear (Ursus thibetanus) and hard mast production of five tree species in cool temperate forest during 2006-2008. The purpose of this study was to test the hypothesis that low mast production affects sexual differences in bear behavior. We summarized the movement pattern of 13 bears in terms of minimum movement distance and cumulative movement distance of the movement path followed during 24 hour. Masting of Quercus crispula acorns was low in 2006, high in 2007 and moderate in 2008. The dominant food items found in bear scats were hard mast, especially Quercus acorns. The percentage of Quercus acorns in the food items in scats was higher in 2007 than in 2006 and 2008. Movement distance of males and females increased in the low mast year. However, the increase of movement distance of females was larger than that of males. Thus, masting influenced the behavior of females more strongly than males. Our results indicated that low mast production changed the food habits and the size of the home range of bears, especially of females. © 2012 The Mammal Society of Japan.

Mise Y.,Tokyo University of Agriculture and Technology | Yamazaki K.,Ibaraki Nature Museum | Yamazaki K.,Tokyo University of Agriculture | Soga M.,Hokkaido University | And 2 more authors.
Ecological Research | Year: 2016

Research on endozoochorous seed dispersal is needed to further understand plant ecology and evolution. There are several methods for calculating the distribution of seed dispersal distances, although many studies use the “combination of gut retention time and movement data” (CGM) method to determine the potential seed dispersal distance distribution (PSD). However, there have been no evaluations of between PSD values acquired by CGM and seed dispersal distance distributions calculated using other methods. The main purpose of this study was to compare methods of determining seed dispersal distance distributions using raccoon dogs (Nyctereutes procyonoides). We calculated estimated seed dispersal distance distribution (ESD) using the bait-marker method and PSD using the CGM method. There were no differences between the ESD and PSD results with regard to basic dispersal distance distributions. The results indicate that if the region from which animal movement data was acquired and the region from which markers for the bait-marker method have been collected are the same, the distance distributions using the two methods may match. Additionally, though there were differences in seed mimic gut retention times (GRTs) between the two baits used (median GRT, fruits: 8 h 50 min, animal materials: 12 h 55 min), there were no differences in PSD between the two baits. This indicates that disperser movement has a stronger effect on dispersal distance distribution than GRT when using the CGM method. © 2016 The Ecological Society of Japan

Koike S.,Tokyo University of Agriculture and Technology | Morimoto H.,Tokyo University of Agriculture and Technology | Goto Y.,Tokyo University of Agriculture and Technology | Kozakai C.,Tokyo University of Agriculture and Technology | Yamazaki K.,Ibaraki Nature Museum
Mammal Study | Year: 2012

We studied insectivory by five carnivores - the Asiatic black bear (Ursus thibetanus), Japanese marten (Martes melampus), Japanese badger (Meles meles), red fox (Vulpes vulpes), and raccoon dog (Nyctereutes procyonoides) - in a cool-temperate deciduous forest in Japan. From May 2003 to April 2005, we assayed 373 fecal samples (91 from bear, 158 from marten, 43 from badger, 36 from fox, and 45 from raccoon dog) for insects. Each carnivore species consumed a variety of insect species, some preferentially. Bears preferred colonial insects like ants and wasps; martens ate a variety of forest insects, such as ground beetles and arboreal insects; badgers preferred forest ground beetles; foxes ate ground beetles and grassland insects; and raccoon dogs ate a variety of species. Dietary preferences may reflect the feeding strategy, behavior, or habitat preference of each carnivore species. Based on the habitat preferences of the insects, we could assign carnivores to particular microhabitats: bears and martens used forest in three dimensions, badgers inhabited forest in two dimensions, foxes used grassland and forest in two dimensions, and raccoon dogs inhabited grassland and forest in three dimensions. Identification of insects in feces may provide information on the dietary and habitat preferences of these carnivores. © The Mammal Society of Japan.

Loading Ibaraki Nature Museum collaborators
Loading Ibaraki Nature Museum collaborators