In order to clarify geomorphologically the developmental processes of the mangrove habitats of Iriomote Island, topographic and surface geological surveys were performed along four lines in and around the mangrove habitat at the mouth of the Urauchi River in northwestern Iriomote Island.
As a result, it was learned that the mangrove habitat of Iriomote Island has migrated in response to relative sea-level changes. It is especially worth noting that the mangrove habitat abruptly moved seaward by a relative sea-level fall that occurred about 1, 000yrs BP. During the rising sea-level phase between 2, 000yrs BP and 1, 000yrs BP, the mangrove forests of the island retreated, landward, which indicates that they are possibly more sensitive to sea-level changes than mangrove forests of tropical areas such as Micronesia and the Philippines, where landward movement of mangroves during this period has not recognized. On the other hand, at the Rhizophora stylosa habitat situated in the inner mangrove forest, it was found that the mangroves have maintained their habitat and position by accumulating mangrove peat against relative sea-level rise after 260yrs BP.

View full abstract

1. Purpose
Since the latter half of 1970's, Japan's population and industrial profile has been remarkably changing, that is, such changes are recognised as rapid increase of aged population, steep reduction of fertility rate, rapid de-industrialization and expansion of the “soft” sectors. But, there is not enough study on how these changes reflect on the urban residential structure. In this paper, the author intends to clarify the recent changes of the characteristics of residents and residential structure in Sapporo City.
Sapporo City, as the capital in Hokkaido, had developed so rapidly that its population increased from 800 thousands in 1970 to 1, 290 thousands in 1985. Thus, it is a suitable city for a case study.
2. Method
Using the population census of 1970 and 1985, setting the “Densely Inhabitated District” for the study area, and using “divided mesh” (about 462m×546m quadrate) for the unit tract, five concentric zones and five radial sectors are defined in the first. In the second, thirty four attributes of residents, which are concerned with age, occupation, family type and tenure of dwelling, are chosen, and the factorial ecological analysis is performed. The major factors extracted by the analysis will suggest the major changes of residential characteristics. Thirdly, as to the attributes which had remarkable loading on each factor, changes of the distribution patterns by zone and sector are surveyed.
3. Findings and discussion
Three major factors were extracted from the factorial ecological analyses in both years. Factor I concerned with the attributes which have zonal pattern, Factor II do with the ones with sectorial pattern, and Factor III do with the ones with living standards. The attributes which have remarkable loadings on each factor are examined on the distribution pattern by zone and sector, and it is clarified that each factor contains the following important changes.
1) Changes of the “zonal” type attributes
These attributes can be classified into two groups. The one is the group of attributes concerning with population and family structure, where aged population ratio's steep increase, infant population ratio's rapid reduction, and steep increase of ratio of single person family and ratio of household with rented house were observed. These chages are much remarkable in the inner area and the old built-up zone. The author thinks these have resulted from the expansion of CBD function of Sapporo and the fundamental change of Japan's population structure.
In the other group, which concerning with occupational structure, ratio of commercial industry's workers were increased more steeply in the outer zone than the central part of the city. This change suggests the dispersion of the commercial function to the outer zone. On the contrary, manufacturing workers' ratio steeply decreased in all zones, which suggests rapid deindustrialization in Sapporo City.
2) Changes of the “sectorial” type attributes
Ratio of blue-collar workers steeply reduced in all sectors, and ratio of professional worker rapidly increased especially in the inner city area. Although both attributes had typically sectorial differentiation formerly, such sectorial differentiation became weaken in 1985. The author thinks that this is the significant change of traditional sectorial pattern of such “socioeconomic” contrast as “blue-collar versus white-collar”.
3) Changes of living standards' attributes
The attributes concerning living standard show two peaks, that is, in the hilly residential sector and in inner city area. In 1970, ratio of owned house households and floor (tatami) space per capita were major attributes concerning with living standard. In 1985, professional workers' ratio newly became important one in addition to floor space per capita, which have brought by both attributes' steep increase especially

View full abstract

This paper seeks to review the Japanese literature in industrial geography concerned with the viewpoint of intra-firm, interregional divisions of labour, and then presents a framework for empirical studies which is able to approach some geographical issues.
In the field of industrial geography, there has been an important methodological theme. This is how to establish links between the national economic and regional perspectives. The viewpoint of intra-firm, interregional divisions of labour has developed in relation to the issues of subcontracting system and the decentralization of manufacturing industry since the middle 1960s in Japan, and was been influenced by the structural approach in the English-speaking countries. This viewpoint focuses on activities of large multi-plant firms and their geographical effects on the national spatial structure, individual regions and so on. The perspective is significant for the methodological issue in industrial geography, and it will contribute to the argument about the wider regional economy, by linking it to the local labour markets and life sphere.
The framework for empirical studies examined and proposed in this paper consists of three aspects as follows. Firstly, concerning the interregional hierarchy, it is important to understand activities of firms, especially their locational strategies, in relation to macro-economic conditions and their effects on individual regions. Secondly, concerning the hierarchy within the individual region, it is necessary to analyze the hierarchical production system and its process of formation, occurred as a result of the strategies of large firms and responses of indigenous subcontractors. Thirdly, the regional characteristics of reproduction system of labour force, considered as the basis of the multi-layered structure, are to be discussed.

View full abstract