The Yamasaki Fault System is the longest active fault system in the Chugoku Mountains, western
Japan, and is composed of seven active faults named the Ohara, Hijima, Yasutomi, Kuresakatouge, Biwakou, Miki, and Kusadani Faults from northwest to southeast. Among these active faults, the latest activity and recurrence interval of the Kuresakatouge Fault have not been clarified in spite of the intense researches after the 1995 Hyogo-ken Nanbu (Kobe) Earthquake. Reexamination of the fault outcrop and a trenching survey were conducted to reveal the recent activity of this fault, at Goji and Okugoji sites, Himeji City, Hyogo Prefecture, respectively. At the Goji site, the sediments deposited after the fall of the Kikai-Akahoya tephra (K-Ah) erupted at 7,300 cal BP were displaced by active faulting, which is considered to be the latest event of the Kuresakatouge Fault. On the other hand, at the trench site of Okugoji, fault displacement was recognized only within the lower part of the gravel beds deposited after the fall of the Sanbe-Ukinuno tephra (SUk) erupted at 20,000 cal BP, and the upper part of the beds and the younger sediments deposited after the fall of K-Ah show non-fault-related deformation. Judging from the small amount of vertical displacement less than 30 cm at the Okugoji trench site, the deformation of the sediments indicates a result by the only one event between 20,000 and 7,300 cal BP. The Kuresakatouge Fault has been activated at least two times during the last 20,000 years, suggesting its longer recurrence interval than those of the other six faults comprising the Yamasaki Fault System.
Aculeate wasps and bees were surveyed at eleven sandy beeches in northern part of Hyogo prefecture. Nesting aggregations of the sand wasp Bembix niponica were found on four beeches, Kehnohama and eastern edge of Takenohama, Toyooka City, and Mitahama and Hamayasuki, Kami Town. These are first reliable records at the coastal area of Japan Sea in Hyogo prefecture. The sites where Bembix niponica populations were found currently seem to be under considerably strong artificial disturbance, and need some conservation efforts such as enlightening to the local people and tourists to promote the understanding of their ecological values. Other six and four species of aculeate wasps and bees were recorded as coastal inhabitants in Kehnohama and Hamayasuki, respectively. Out of a total of 25 species obtained in both beeches, three were endangered species appeared in national and prefectural red data books. This fact may indicate that sandy beeches in this area are important habitats for sand
wasps and bees.
We investigated changes in community structure and influence of management on the vegetation
over a 27-year period in the shrine forest at Hino Shrine, southeastern Hyogo Prefecture. Diversity and abundance of woody species decreased from 1978 to 2005. Populations of Ardisia creanata, Cleyera japonica, and seedlings of Ilex rotunda, all of which are lucidophyllous forest species, declined in the understory. Trachycarpus fortunei, an invasive ornamental species, increased in the managed plots. In addition, relative growth rates of small- and medium-diameter trees increased in the managed plots. Our results suggested that management, such as cutting vines and removing leaf and branch litter, promotes tree growth, but may also cause invasion of the understory by non-native species. Because the forested area of Hino Shrine is small and isolated in an urban landscape, the community structure is affected significantly by the surrounding environment. Therefore, active management, such as planting understory trees, improving soil water conditions, removing invasive species, and creating safe-sites for seedling establishment, may be required to maintain native forest conditions.
A lucidophyllous forest on Mt. Kurino-dake, Kagoshima Prefecture, was studied in order to clarify
species composition of epiphytes and the relationship between tree sizes (height and DBH) and species richness of epiphytes on each tree. In this area, a total of 128 trees (21species), including 24 Distylium racemosum, 21 Persea thunbergii, 14 Camellia japonica, 12 Quercus salicina, 12 Cleyera japonica and 45 others, were chosen as the sample trees. The epiphytes on the sample trees comprised 25 species, including Lemmaphyllum microphyllum, Lepisorus onoei, Dendrobium moniliforme and Bulbophyllum drymoglossum. The species richness (the number of species) of the epiphytes on each sample tree had a high positive correlation with tree DBH (cm). This relationship was expressed by the regression formula: y=0.13x-1.0 (where y is the number of species, and x is DBH (cm) of the sample tree).
Of the 1,602 specimens collected at the Rokko Mountains, Hyogo Prefecture, in 2006, 176 species
of 112 genera in 41 families of Musci, 90 species of 44 genera in 28 families of Hepaticae, and one
species in one genera in one families of Anthocerotae enumerated. Among them, four RDB species of Japan and ten RDB species of Hyogo Prefecture were recognized.