Mammal Study
Volume 37, Issue 4, 2012
Volumes & issues:
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Original papers
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Seasonal Habitat Partitioning Between Sympatric Terrestrial and Semi-Arboreal Japanese Wood Mice, Apodemus speciosus and A. argenteus in Spatially Heterogeneous Environment
View Description Hide DescriptionAbstract.Habitat partitioning can maintain the coexistence of species with very similar ecological traits. We studied habitat partitioning between terrestrial and semi-arboreal congeneric rodents (Apodemus speciosus and A. argenteus) that often coexist despite asymmetry in their competitive abilities. To understand seasonal and habitat variation in their partitioning, we evaluated seasonal variation in food resources, habitat use, and habitat similarity between the species in a site comprising a mixture of grassland, pine forest, and mixed forest. Food resources were available on the ground in all vegetation types in spring and autumn, but were severe in summer. Apodemus speciosus was observed in all types of vegetation on the ground. In contrast, A. argenteus was observed on the ground and on trees in pine forest, especially areas where the understory is covered by dwarf bamboo. Habitat similarity tests revealed that habitat partitioning between two Apodemus species may vary seasonally, and the relationship depends on habitat structure. This study suggests that the mechanism of habitat partitioning between terrestrial and semi-arboreal rodents in temperate forest is more complex than previously recognized.
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Reproductive Physiology of Hipposideros terasensis in Taiwan
View Description Hide Description[Abstract.Changes in habitat and resource availability have induced bats to develop strategies for reproductive delay, including the processes of insemination, embryo implantation, and fetal development. Hipposideros terasensis used the strategy of delayed embryonic development. Bats mated in autumn. Fertilized eggs implanted during the blastula stage, but remained dormant for as long as five months before developing. In male bats, concentrations of testosterone increased from baseline to peak (54.3 ± 4.7 ng/ml) in August, corresponding with spermatogenesis. For female bats, concentrations of progesterone increased to peak levels (27.2 ± 6.8 ng/ml) between February and April, before declining back to baseline after birth in June. Increase and decline coincided, respectively, with resumption of embryo development (March to May) and birth (May to June). Compared to other hibernating species or species with similar reproductive patterns, H. terasensis had similar reproductive quiescence and changes and regulation of reproductive hormones.
, Abstract.Changes in habitat and resource availability have induced bats to develop strategies for reproductive delay, including the processes of insemination, embryo implantation, and fetal development. Hipposideros terasensis used the strategy of delayed embryonic development. Bats mated in autumn. Fertilized eggs implanted during the blastula stage, but remained dormant for as long as five months before developing. In male bats, concentrations of testosterone increased from baseline to peak (54.3 ± 4.7 ng/ml) in August, corresponding with spermatogenesis. For female bats, concentrations of progesterone increased to peak levels (27.2 ± 6.8 ng/ml) between February and April, before declining back to baseline after birth in June. Increase and decline coincided, respectively, with resumption of embryo development (March to May) and birth (May to June). Compared to other hibernating species or species with similar reproductive patterns, H. terasensis had similar reproductive quiescence and changes and regulation of reproductive hormones.
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Intraspecif Phylogeny and Nucleotide Diversity of the Least Shrews, the Sorex minutissimus-S. yukonicus Complex, Based on Nucleotide Sequences of the Mitochondrial Cytochrome b Gene and the Control Region
View Description Hide DescriptionAbstract.Phylogenetic analysis was conducted for various populations of the Sorex minutissimus-S. yukonicus complex based on mitochondrial gene (cytochrome b and/or the control region) sequences. Sorex minutissimus was divided into some monophyletic groups in Eurasia; it was divided into 2 main groups, eastern and western Eurasian clades, based on combined data of the cytochrome b and the control region. Monophyly of shrews from Hokkaido-Sakhalin, Primorye, Mongolia-Transbaikalia, southeastern Finland was strongly supported respectively in most analyses. Sorex yukonicus was phylogenetically close to S. minutissimus in eastern Siberia. Some shrews from western and central Siberia were included in the clade of southeastern Finland. Also, most shrews from central-northern Finland and Norway made a clade close to but different from the southeastern Finland clade. This finding suggests that Fennoscandian shrews might consist of individuals which were recolonised from various refugia after the Last Glacial Maximum. Nucleotide diversity of shrews from Hokkaido and Alaska was low. Three regional groups in Kamchatka-Sakha, Sakhalin, and Mongolia-Transbaikalia tended to have medium nucleotide diversity. In contrast, shrews from Cisbaikalia-western Siberia and Fennoscandia had high nucleotide diversity. The S. minutissimus-S. hosonoi group appears to have experienceed a quit different biogeographic history from two shrews with similar ranges, the S. caecutiens-S. hosonoi group and S. tundrensis.
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Comparison of Mammalian Communities in a Human-Disturbed Tropical Landscape in East Kalimantan, Indonesia
View Description Hide DescriptionAbstract.To examine the impact of human disturbance on mammalian community in a human-disturbed tropical landscape in Borneo, we conducted a baited camera trapping study in East Kalimantan, Indonesia, from 2005 to 2010. Along a gradient of habitat degradation, we established four camera trapping sites within a 20-km radius, one in Sungai Wain Protection Forest and three in Bukit Soeharto Grand Forest Park. From the camera trapping carried out for 1,017 camera-days, we obtained 3,753 images of 29 mammal species, including an alien species, the domestic dog (Canis lupus familiaris). The trapping efficiency and species composition of mammals recorded differed between the two kinds of bait (banana and shrimp). The number of species decreased, and the species composition changed along the gradient of habitat degradation, suggesting that human-mediated habitat degradation has a significant effect on the mammalian communities. Our results suggest that forest cover is essential for at least 14 out of 29 recorded mammal species to survive, and that the forest fires and habitat isolation strongly affect particular species, i.e. Lariscus insignis and Trichys fasciculata (Rodentia) and Arctogalidia trivirgata (Carnivora).
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Dietary Partitioning in Sympatric Large Carnivores in a Tropical Forest of Western Ghats, India
View Description Hide Description[Abstract.We investigated dietary partitioning among tiger Panthera tigris, leopard Panthera pardus and dhole Cuon alpinus in Mudumalai Tiger Reserve, India between January 2008 and April 2010 based on scat analyses and prey surveys. Scat analysis revealed that though the diet of the three predators consisted of 15 to 21 prey species, wild ungulates formed a major portion of their diet (88.4 to 96.7%). The three predators exhibited high diet overlap (> 61%). Prey availability, estimated from an effort of 473 km of line transects (n = 33) revealed high density of chital Axis axis (43.8 ± 10.7 (mean ± SE) individuals/km2), followed by langur Semnopithecus entellus (31.0 ± 3.8), gaur Bos gaurus (6.7 ± 1.5), giant squirrel Ratufa indica (6.4 ± 1.3), sambar Rusa unicolor (4.9 ± 0.96) and elephant Elephas maximus (4.9 ± 0.75). Mean biomass (kg/km2) of chital, gaur and sambar was 2058.6, 3015 and 656.6 respectively. In terms of biomass, tiger consumed mostly large sized prey (> 50 kg). Although leopard and dhole selected mostly medium-sized (11–50 kg) prey (chital), the second most important prey was sambar for dhole and langur for leopard. The results suggest that high density of different-sized prey in Mudumalai Tiger Reserve helped facilitate coexistence of tiger, leopard and dhole, despite the high dietary overlap, although some dietary partitioning was apparent when considering prey size and prey selection.
, Abstract.We investigated dietary partitioning among tiger Panthera tigris, leopard Panthera pardus and dhole Cuon alpinus in Mudumalai Tiger Reserve, India between January 2008 and April 2010 based on scat analyses and prey surveys. Scat analysis revealed that though the diet of the three predators consisted of 15 to 21 prey species, wild ungulates formed a major portion of their diet (88.4 to 96.7%). The three predators exhibited high diet overlap (> 61%). Prey availability, estimated from an effort of 473 km of line transects (n = 33) revealed high density of chital Axis axis (43.8 ± 10.7 (mean ± SE) individuals/km2), followed by langur Semnopithecus entellus (31.0 ± 3.8), gaur Bos gaurus (6.7 ± 1.5), giant squirrel Ratufa indica (6.4 ± 1.3), sambar Rusa unicolor (4.9 ± 0.96) and elephant Elephas maximus (4.9 ± 0.75). Mean biomass (kg/km2) of chital, gaur and sambar was 2058.6, 3015 and 656.6 respectively. In terms of biomass, tiger consumed mostly large sized prey (> 50 kg). Although leopard and dhole selected mostly medium-sized (11–50 kg) prey (chital), the second most important prey was sambar for dhole and langur for leopard. The results suggest that high density of different-sized prey in Mudumalai Tiger Reserve helped facilitate coexistence of tiger, leopard and dhole, despite the high dietary overlap, although some dietary partitioning was apparent when considering prey size and prey selection.
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Genetic Variation and Population Structure of the Sable Martes zibellina on Eastern Hokkaido, Japan, Revealed by Microsatellite Analysis
View Description Hide Description[Abstract.To assess the genetic variation and population structure of the sable Martes zibellina on eastern Hokkaido, Japan, we analyzed genotypes of 12 microsatellite loci on 48 individuals. Genotypes for all individuals examined were found to be different from each other. Mean observed and expected heterozygosites and allelic richness were calculated to be 0.52 (0.02–0.80), 0.58 (0.02– 0.79) and 5.49, respectively. The genetic diversity of the eastern Hokkaido population was similar to those of farm-bred sables in Russia and other mustelids. STRUCTURE analysis showed that the sables of eastern Hokkaido were grouped into two genetic clusters. Eighty-nine percent (24/27) of individuals assigned to cluster 1 were distributed around Shiretoko Peninsula, whereas 81% (17/21) assigned to cluster 2 were distributed in the inner side of Hokkaido (Tokachi District). The two subpopulations could have been genetically differentiated due to geographic barriers such as higher mountains, lakes, rivers and solfatara areas, although the geographic isolation did not seem to be complete.
, Abstract.To assess the genetic variation and population structure of the sable Martes zibellina on eastern Hokkaido, Japan, we analyzed genotypes of 12 microsatellite loci on 48 individuals. Genotypes for all individuals examined were found to be different from each other. Mean observed and expected heterozygosites and allelic richness were calculated to be 0.52 (0.02–0.80), 0.58 (0.02– 0.79) and 5.49, respectively. The genetic diversity of the eastern Hokkaido population was similar to those of farm-bred sables in Russia and other mustelids. STRUCTURE analysis showed that the sables of eastern Hokkaido were grouped into two genetic clusters. Eighty-nine percent (24/27) of individuals assigned to cluster 1 were distributed around Shiretoko Peninsula, whereas 81% (17/21) assigned to cluster 2 were distributed in the inner side of Hokkaido (Tokachi District). The two subpopulations could have been genetically differentiated due to geographic barriers such as higher mountains, lakes, rivers and solfatara areas, although the geographic isolation did not seem to be complete.
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Partial Migration and Effects of Climate on Migratory Movements of Sika Deer in Kirigamine Highland, Central Japan
View Description Hide Description[Abstract.Studies on migration pattern of sika deer in Japan are limited. We captured 27 sika deer and identified movement for 24 deer (17 females and 7 males) from 2008 to 2011 in Kirigamine Highland, Nagano, central Japan. Four juvenile males dispersed from their original home range, and we documented migration pattern for 23 deer (17 females and 6 males), including 3 dispersed males. Deer exhibited partial migration, regardless of sex: 65% (n = 15) of the deer were migratory, whereas 35% (n = 8) were non-migratory. All but 1 of the migratory deer migrated between high-elevation summer range and low-elevation winter range. Mean migration distance was 9.9 km (range = 3.2– 22.9 km). Fidelity to summer home range was stronger than fidelity to winter home range. In order to determine the effect of climate on the onset of migration at Kigiramine Highland, we examined 39 seasonal movements during 4 migratory periods. Most of autumn migrations occurred before the snow depth reached 20 cm. Spring migrations occurred after the daily temperatures > 0°C persisted for more than 3 days, and during periods when either snow had completely disappeared or snow melted rapidly.
, Abstract.Studies on migration pattern of sika deer in Japan are limited. We captured 27 sika deer and identified movement for 24 deer (17 females and 7 males) from 2008 to 2011 in Kirigamine Highland, Nagano, central Japan. Four juvenile males dispersed from their original home range, and we documented migration pattern for 23 deer (17 females and 6 males), including 3 dispersed males. Deer exhibited partial migration, regardless of sex: 65% (n = 15) of the deer were migratory, whereas 35% (n = 8) were non-migratory. All but 1 of the migratory deer migrated between high-elevation summer range and low-elevation winter range. Mean migration distance was 9.9 km (range = 3.2– 22.9 km). Fidelity to summer home range was stronger than fidelity to winter home range. In order to determine the effect of climate on the onset of migration at Kigiramine Highland, we examined 39 seasonal movements during 4 migratory periods. Most of autumn migrations occurred before the snow depth reached 20 cm. Spring migrations occurred after the daily temperatures > 0°C persisted for more than 3 days, and during periods when either snow had completely disappeared or snow melted rapidly.
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Karyotype of the Gansu Mole (Scapanulus oweni): Further Evidence for Karyotypic Stability in Talpid
View Description Hide DescriptionAbstract.Little is known about the ecology and evolution of the Gansu mole (Scapanulus oweni). The morphology of this monotypic genus (Talpidae, Eulipotyphla, Mammalia) indicates that it should fall into the tribe Scalopini. Although all the other scalopines are distributed in North America, S. oweni is endemic to Central and Southwest China. Previous studies have indicated that the chromosomes of talpid moles exhibit remarkable stability. However, the karyotype of S. oweni has not been determined. In this study, we report the karyotypes including G-banding and C-banding patterns of S. oweni. The diploid and fundamental autosomal numbers are 34 and 64, respectively, identical with six other talpid species and thus providing another line of evidence for chromosomal uniformity in this family. The models of karyotype stability are discussed, none of which adequately explains the chromosomal conservatism. We suggest that comprehensive approaches are needed to test in which degree that the chromosomal rearrangement, phylogeny, phylogeography and ecological adaptation have shaped the chromosomal evolution in this family.
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Short communications
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Reproductive Activity of the Small Japanese field mouse (Apodemus argenteus) in Yamaguchi Prefecture, Japan
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Preliminary Study on Microsatellite and Mitochondrial DNA Variation of the Stone Marten Martes foina in Bulgaria
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