Mammal Study
Volume 36, Issue 2, 2011
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Original papers
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Mass-Intrusion-Induced Temporary Shift in the Genetic Structure of an Asian Black Bear Population
View Description Hide DescriptionAbstract.Some Asian black bears inhabiting Japan are known to invade residential areas, a phenomenon known as mass intrusion. Although mass intrusion occurs in autumn, it can result in genetic mingling. We examined the influence of intrusion on the genetic structure of black bears. Tissue samples were collected from invasive bears in central Japan in the autumn of two mass-intrusion years, 2004 and 2006. We also set hair traps overlapping an area where tissue samples were collected in the summers of 2005, 2006, and 2008. The genotypes of eight microsatellite loci were determined by PCR. Pairwise relatedness (rxy ) was negatively correlated with distance among resident bears, whereas no such relationship was observed among invasive bears. Spatial autocorrelation analysis of the normal bears in 2006 revealed a significantly positive rc value within the 0––65-km-distance class, whereas that of invasive bears in 2006 revealed significantly positive rc values between the 0––15- and 0––65-km-distance classes. We therefore concluded that mass intrusion enabled genetic mingling in autumn leading to alteration of the genetic structure; however, the normal structure subsequently recovered with seasonal movement.
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Rumen Contents of the Sika deer in Wakayama Prefecture, Southern Honshu: A New Demonstration of Latitudinal Variations of the Food Habits
View Description Hide DescriptionAbstract.We analyzed 78 rumen content samples obtained in middle and southern parts of Wakayama Prefecture, the southern-most part of Honshu, the main island of Japan from 1995 to 1998. The rumen contents were dominated by browse (leaves of woody plants). Evergreen broad-leaves such as Quercus spp., Eurya japonica, Ligustrum japonicum, and Aucuba japonica were dominant, occupying 30––45%. Deciduous broad-leaves including Rubus spp., Hydrangea luteo-venosa, and Callicarpa mollis accounted for 20––35%. Forbs accounted for 10––20%. Non-synthetic organs like twigs and bark accounted for only 2––5%, and graminoids and ferns appeared little. These results suggest that foods of the Wakayama deer are good in quality, particularly in winter. The comparison has shown that the Wakayama deer are categorized into the typical southern browser type. Geographical variations of the food contents of sika deer are demonstrated by greater contributions of graminoids as well as by summer-winter differences in the northern grazer type than the southern browser type. Percentage similarity (PS, Whittaker 1952) well demonstrated seasonal variations of dietary compositions.
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Methods for Constructing a Wild Boar Relative-Density Map to Resolve Human-Wild Boar Conflicts
View Description Hide DescriptionAbstract.Lethal controls have been used to control human-wild boar conflicts. However, these methods do not work satisfactorily, as their effectiveness is variable. Previous study has revealed that a reason for this variation is inter-individual differences in damage-causing behavior (i.e., damagecausing vs. non-damage-causing wild boars). To reduce crop damage effectively, selective culling should be conducted, but information on the density distribution of damage-causing wild boars is lacking. To build a practical density-distribution map of damage-causing wild boars, we examined the relationship between crop-damage data and 2 + 1 quasi-density maps (B-cpue, B-dm, and PC maps constructed using CPUE (catch-per-unit-effort) data, wild boar-distribution binary data, and principal components of B-cpue and B-dm, respectively). Regression analyses indicated that binary wild boar-distribution data (B-dm) had the best potential for development into a relative-density map. Binary data can be easily collected with little time, cost, or effort; thus, wildlife managers can use this method for effective management. Damage-causing factors include not only wild boar density, but also environmental factors (e.g., topography). Therefore, wildlife managers should recognize which factors induce damage in each region. If high density is the main damage-inducing factor, wildlife managers can use a lethal control method, but if damage-inducing factors are environmental, nonlethal methods such as fencing might be employed. Our density map enables wildlife managers to select areas in which intensive culls of damage-causing wild boars should be conducted.
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A Morphological Analysis of Malaysian Kerivoula (Chiroptera, Vespertilionidae)
View Description Hide DescriptionAbstract.Recent identification of new species within the genus Kerivoula from the Southeast Asian region has indicated that this genus was understudied and currently underestimated in terms of its species diversity. Thus, this morphological study was carried out to record and analyse the morphological characters of available specimens of Malaysian Kerivoula from the Museum of Zoology, Universiti Malaysia Sarawak. Thirty-one external, skull and dental characters were taken and analysed using the multivariate analysis, dicriminant function analysis. As the result, six groupings of Kerivoula was identified, namely K. intermedia, K. hardwickii, K. pellucida, K. lenis and K. papulosa which were divided into two distinctive groupings of K. papulosa type large (K. papillosa type L, hereafter) and K. papillosa type small (K. papillosa type S, hereafter). Variable dentary length was identified as the best predictor to characterize each group of Kerivoula. The separation of the K. papulosa specimens into two separate morphotypes were characterised by their different sizes whereby the former group was larger in size compared to the latter. It is suggested that each represents an independent species even though both morphotypes occur sympatrically. The homogenising effect of the previous environmental events might have been the primary factor of the sympatric occurrence of both morphotypes. Nevertheless, further study regarding ecology, morphology and genetics should be carried out to provide a better insight regarding the cryptic population of K. papillosa in Borneo and Malaysia.
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Short communications
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A Note on the Genetic Status of the Dark Red-Backed Vole, Myodes rex, in Hokkaido, Japan
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Detecting Nesting Trees of Siberian Flying Squirrels (Pteromys volans) Using Their Feces
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Preliminary Survey of Habitat Use by Sciurus vulgaris orientis in a Natural Forest of Hokkaido Island, Japan
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A Low-Cost, Low-Labor-Intensity Electric Fence Effective Against Wild Boar, Sika Deer, Japanese Macaque and Medium-Sized Mammals
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