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Fragmentation of forest habitat has negative effects on arboreal mammals, compromising their natural dispersal and foraging movements. This paper describes an evolving series of mitigation measures aimed at creating cost-effective continuity pathways for arboreal mammals in Japan. The projects have focused on the endemic Japanese dormouse (Glirulus japonicus) a scarce, but popular and iconic species which provides an effective vehicle for environmental education and public engagement.

Nucleotide sequences of the mitochondrial D-loop region were examined in three wild rodents (Apodemus argenteus, Apodemus speciosus, and Myodes smithii) on the northern slope of Mt. Fuji, the highest mountain in Japan, to elucidate the past evolutionary and present anthropogenic processes shaping their genetic diversity. Nucleotide diversity, median-joining network, and mismatch distribution analyses suggested that A. argenteus has multiple divergent lineages, possibly due to multiple previous expansion events, whereas A. speciosus and M. smithii are younger lineages that could be derived from single expansion events. These findings indicate that Mt. Fuji plays an important role as a reservoir maintaining lineages through multiple past expansion events. Artificial infrastructure also affected the genetic diversity of the two Apodemus species, as populations of these species on the two sides of the Fuji Subaru Line roadway were genetically distinct. To construct a proper conservation strategy based on genetic diversity, we suggest that the past and present contributors to genetic diversity must be clarified. Such clarification is especially important for the Mt. Fuji environment, which harbors rich biodiversity but also incurs much human impact as a national park.

This study investigated the little known winter ecology of Japanese dormice by monitoring body temperature patterns and winter activity in captive and free-living animals. Before onset of hibernation, animals exhibited a transitional phase characterized by frequent bouts of daily torpor. During hibernation itself, dormice aroused periodically from torpor but never foraged during arousals. Torpor bout duration tended to be shorter around the beginning and end of the hibernation period than during the intervening mid-hibernation period. In a further radio-tracking study of two free-living dormice, both were observed to construct a shallow underground hibernaculum at a depth of 1–5 cm and to enter hibernation alone. One individual left the nest after it was disturbed, while the other dormouse stayed in its nest and continued hibernating normally, exhibiting periodic arousal but never feeding or moving from the hibernaculum. These first detailed observations of hibernation in Japanese dormice are in good accordance with previous studies of European dormouse species.

We previously revealed the presence of six genetically distinct matrilineal populations of the Japanese dormouse Glirulus japonicus in the distribution range of Honshu, Shikoku, and Kyushu islands. In this study, we extended this analysis using mitochondrial cytochrome b gene sequences (n = 96) and Y-chromosome-specific SRY gene sequences (n = 22) from individuals collected from Honshu, Shikoku, Kyushu, and Oki Dogo I. The cytochrome b sequence data allowed us to define precise geographic ranges of the six previously known and three newly found distinct matrilineal lineages: northeastern Honshu (I), east-central Honshu (II), west-central Honshu and the Kii Peninsula (III), the western part of Honshu (IV), Shikoku (V), westernmost Honshu and Kyushu (VI), the northern part of central Honshu (VII), the southern part of central Honshu (VIII), and Oki Dogo I. (IX). Our inference of geographic borders suggests that regions of lower and higher altitudes in the mountain systems played important roles in driving the hosting and separation of lineages, respectively. Six matrilineal lineages (I, II, V, VI, VIII, and XI) were shown to possess their own SRY haplotypes, while lineages III and IV shared one haplotype. These data together with our previous observation of nuclear ribosomal RNA gene variation indicate advanced populational subdivision in this species. It is thus evident that each of the populations, including those living at high latitudes and in limited geographic spaces, have survived for several million years. A specific ability to tolerate cold may have permitted G. japonicus to preserve anciently diverged lineages in each locality.

The sequences of the mitochondrial cytochrome b gene and restriction site variation in the spacer region of the nuclear ribosomal RNA gene [rDNA-restriction fragment length polymorphism (RFLP)] were analysed to determine the phylogeographic structure of the Japanese dormouse (Glirulus japonicus), which is threatened by deforestation and has been designated an endangered species in Japan. The phylogenetic tree of cytochrome b grouped G. japonicus into six geographical populations: north-eastern Honshu (I), central Honshu (II), west-central Honshu/Kii Peninsula (III), western Honshu (IV), Shikoku (V), and westernmost Honshu/Kyushu (VI); the genetic distances among these groups suggest divergence in the Late Tertiary. The lineage of group VI was located at the basal position in the phylogenetic tree, followed by the radiation of the other lineages. An rDNA-RFLP analysis of 15 restriction sites roughly supported such genetic isolation; groups I, II, III, IV, V and VI have five, two, one, one, one and four unique restriction sites, respectively, revealing four geographic groups as cryptic species: I, II, III + IV + V and VI. Our results reveal the ancient divergences of the local population, which has a complicated evolutionary history, and should be useful in developing a framework for the conservation of this species. Resumen Secuencias del gen mitocondrial citocromo b y variaciones en sitios de restriccion en la region espaciadora del gen nuclear de ARN ribosomal [rARN-fragmentos de restriccion de polimorfismos de longitud (RFLP)] fueron analizados para determinar la estructura filogeografica del liron japones (Glirulus japonicus), el cual es amenazado por deforestacion y ha sido designado como especie en peligro de extincion en Japon. El arbol filogenetico usando el gen mitocondrial citocromo b revelo que individuos de las especie G. japonicus estan divididos en seis regiones geograficas: (I) el Noreste de la isla de Honshu, (II) el centro de la isla de Honshu, (III) el oeste central de la isla de Honshu/la peninsula de Kii, (IV) el oeste de la isla de Honshu, (V) la isla de Shikoku y (VI) la region mas al oeste de las islas de Honshu y Kyushu. Las distancias geneticas entre estos grupos sugieren que la divergencia entre ellos ocurrio durante el Terciario tardio. El grupo VI ocupo el punto mas basal del arbol filogenetico, seguida de la radiacion de los otros grupos. Nuestro analisis de rADN-RFLP de 15 sitios de restriccion corroboraron los resultados del gen mitocondrial respecto al aislamiento genetico: los grupos I, II, III, IV, V y VI poseen cinco, dos, uno, uno, uno y cuatro sitios de restriccion unicos, respectivamente. Estos resultados permitieron reconocer cuatro grupos geograficos, I, II, III + IV + V y VI como una especie criptica. Los datos presentados aca revelan la divergencia ancestral de las poblaciones de Japon, las cuales presentan una complicada historia evolutiva. Estos datos seran de gran valor al momento de desarrollar estrategias de conservacion de esta especie.

Eight microsatellite markers were developed for the Japanese dormouse (Glirulus japonicus), a natural monument and near-threatened species in Japan. The markers amplify in individuals from all of the mitochondrial lineages detected in a previous study. Numerous polymorphisms were detected in specimens from a local population in central Honshu (11-21 alleles per locus; n = 31) and from the entire distribution range of the species (19-41 alleles per locus; n = 152). These microsatellites will be useful in conservation genetic studies of G. japonicus.

The structural materials of twenty one nests of the Japanese dormouse Glirulus japonicus (Schinz, 1845) collected at Mt Fuji and Mt Akadake in 1988, were analyzed. Fifty seven species of bryophytes were found: 42 species of Musci and 15 of Hepaticae which constituted the major portion of the materials sampled. Most of these species were epiphytes on tree trunks, and this confirms the supposition that the Japanese dormouse uses aboreal space.

The Japanese dormouse, Glirulus Japonicus, is the only extant lineage that represents this genus and it has been classified as a single species distributed on the three main islands of Japan, namely Honshu, Shikoku and Kyushu. However, individuals collected from Fukui, Wakayama and Kochi Prefectures (southwestern part of Japan) yielded distinctly different profiles of restriction fragments of the nuclear ribosomal DNA (rDNA) spacer from those collected from Yamanashi and Nagano Prefectures (central Japan). The estimated sequence divergence between the two groups was 2.8% on average, which corresponds to a putative divergence some two million years ago. Representing mitochondrial DNA (mtDNA) sequences, 402 bases of cytochrome b gene were determined by direct sequencing and the estimated extent of the sequence divergence between the two groups was 6.5-7%. Differences between the two geographic groups were also substantial in the sequences of about 300 base-fragments from the Y-linked, sex-determining locus, Sry. To assess the phylogenetic relationships between the Japanese dormouse and members of the family Myoxidae, we compared sequences of mitochondrial 12S rRNA gene of Japanese dormice with those of the forest dormouse (Dryomys nitedula) and the common dormouse (Muscardinus avellanarins), two continental genera thought to be closely related to the genus Glirulus. The results showed that the sequences from Japanese dormice were distinct from any sequences of the two continental species and the extent of the differences were somewhat similar to that between the rat (Rattus norvegicus) and the hamster (mesocricetus auratus).

Different places of hibernation of Glirulus japonicus were monitored. The home range of a male was larger than that of a female, and they overlapped. The adult female remains in her home range for several years and has litters, while the young female moves from the mother's home range. The Japanese dormouse eats bark, pollen and insects. It sometimes saved food as food-cache in autumn.