In Japan, dune vegetation and its endemic species are now in danger of extinction. Not more than a hundred years ago, it was not difficult to find extensive sandy beaches with huge dunes along the seashore. Like many other natural ecosystems, however, the area and number of extensive sandy beaches covered by typical dune vegetation had considerably decreased with the advance of modernization. In this review the process and the reason for the decrement of dune vegetation was described and discussed. Actually, average width of the sandy beach, which is the distance from the shoreline to the landward boundary of the sandy beach, decreased to 1/4 in recent 40 years. Most of the sandy beaches remained are now narrow beaches with no dunes. Disappearance of extensive sandy beach was mostly due to the organized plantation of pine along the beach and development of beach area from landward side. Since pine plantation protected the landward side from the strong wind bearing salt spray and sand from the shore, the environment of the land behind the pine plantation became mild as inland. Following the establishment of the plantation, landward side, which was once a sandy dune, was converted into agricultural field or urban area. Erosion, which was mostly caused by artificial alteration of the water system of seashore and river, is a one more factor which made the beach narrower from the seaward side. With the object to stop the erosion, long and huge breakwater made of concrete was frequently constructed on the beach in Japan. This massive concrete structure also destroyed the ecosystem of sandy beach. As a result, sandy beach and dunes became in this few decades one of the most threatened ecosystems in Japan.

View full abstract

Tottori sand dunes is protected as the natural monument and the national park, and has accepted many tourists at present. Once it had a plan to establish coastal forest all around the sand dunes at just after World War II and today's state has been implemented after many twists and turns. In this research, I studied vegetation change of Tottori sand dunes after WWII based on the report of research conducted in the past, an old edition topographical map, past air photographs, and field investigation. The area of Tottori sand dunes which remains at present constituted about 12% of the area which existed 100 years ago. The basic vegetation structure in Tottori sand dunes has maintained during the last 40 years which dominated by Carex kobomugi and Ischaemum anthephoroides. Vegetation arrangement of the dunes is A. coastal vegetation zone, B. non-vegetation zone, C. hollow vegetation zone, and D. inland vegetation zone. However, the non-coastal plants increased in the sand dunes, and it has been necessary to suppress the growth of these plants. The vegetation of Tottori sand dunes has been significantly affected by the changes in the local social structure through afforestation and vegetation management. It is necessary to consider the state of future Tottori sand dunes.

View full abstract

Only 15% of beach and dune plants were listed in the 4th version of the Japanese Red List, whereas 46% of salt marsh plants and 36% of sea cliff plants were listed. In contrast, the extinction cases at prefectural levels were higher in beach and dune plants than in sea cliff plants. The extinction rate of beach and dune plants was high in Osaka, Kanagawa, Wakayama and Ibaraki prefecture. As species, Honckenya peploides var. major, Thermopsis lupinoides, Mertensia maritime ssp. asiatica, Fimbristylis sericea, Linaria japonica, Lippia nodiflora and Scutellaria strigillosa were ranked in high risk categories in many prefectural RDBs and the need for conservation was high, although they did not ranked in the Japanese Red List. Local extinction of beach and dune plants might cause decrease of genetic diversity. Additionally, local extinction also may induce collapse of meta-population structure and extinction vortex. Genetic spatial structure and meta-population structure of beach and sand dune plants in Japan are not completely understood. Revealing them is an important theme in future.

View full abstract

Ishikari coast located in the middle of Hokkaido is a natural sandy coast in Ishikari city and Otaru city. Although Ishikari Bay new port were constructed in 1982 on the center of Ishikari coast, these coastal landscapes were consisted with the diverse ecosystem especially with natural vegetation which shows definite zonation by coastal dune plants and natural forest. Results showed that Ishikari coast was natural in comparison with the other famous natural sandy coast. In addition, there were no such natural sandy coast in metropolitan area in Japan. However, the disturbance of coastal dune vegetation and change of the topography itself has become remarkably by the non-managed recreational use such as indiscriminate harvesting of edible plants or ORV (Off-Road Vehicle) driving on beach and dune area since 1970's. Ishikari city designated protection area on about 40ha coastal dune area, and established the research and educational center for coastal plants and environmental education to conserve the coastal vegetation. Because ORV drive was continued in most beach and dune areas, appropriate management were needed for sustainable use throughout the Ishikari coast. At the administrations side, enlargement of prohibited area of ORV drive and Liaison Conference consisted of the administration officers in Ishikari coast area was installed. At the citizens side, voluntary based activities, e.g. beach clean up, adoption of country code, proposal of foot path route, etc., were conducted. Now various subjects who related to Ishikari coast, start to discuss the sustainable recreational use management and conservation of coastal area to establish the autonomous coastal area management by various subject forming the new public.

View full abstract

The Japanese coastal dune plants and vegetation had been declining all over the country since 1980s. For the conservation of them, three important points must be taken into account as follows. First, coastal vegetation in the world have been studied over hundred years because of their scientific importance. The Japanese Ministry of the Environment categorized the coastal dune vegetation as “natural meadow”, of which degree of naturalness is 10, the highest degree. Thus, coastal sand dune vegetation are quite important in nature conservation in Japan. Second, in spite of their importance, most of the Japanese coastal sand dune vegetation have already been lost or critically damaged. Furthermore, future sea-level rising by 1 m, which is estimated to be caused by the global warming, will eliminate over 90% of the present coastal sand dune area. However, plant species native in coastal sand dune area in Japan are rarely listed in the red list made by the Japanese Ministry of the Environment, so that their scientific and social recognition is quite low. The Great East Japan Earthquake in 2011 caused huge tsunami and serious land subsidence. Their effects on coastal area must be monitored to reevaluate the ranks of coastal dune plants in the red list. Third, illustrated books of Japanese coastal plants were not published for the last several decades and almost all of the old ones are out of print and hard to be seen. It is required to publish a new one and some more guidebooks to promote social and scientific recognition. The Japanese Coast Act was amended in 1999 and a new aim was added; “maintenance and conservation of coastal environment”. The actual plans to achieve this new aim must be made by each local government. Thus, collaborative studies and projects with researchers in the field of Ecology, Environmental Technology and other practical sciences, and staffs of Ministry of Land, Infrastructure, Transport and Tourism, local governments and other corresponding organizations, are prerequisite to conserve the Japanese coastal dune plants and vegetation.

View full abstract

Red Claw Crab (Chiromancers haematocheir) requires a different habitat in each stage of their life cycle; estuary area at larval stage before metamorphosis, then forest during maturing and matured stages. Using this crab as an ecological indicator, suitability of landscape element types in urban park as wildlife habitat was evaluated. Results showed; 1) spaces in and along an artificial stream were favored by the crab, which were located along a forest edge, while bare ground was disfavored, 2) in the forest, holes of stonewall were selectively used, 3) in the artificial stream, areas shaded by planted grasses and stones were preferred, and 4) at a time for larva spawning, a place with an old type stonewall, which has many large holes and vegetation, was selectively used. Water supply by the artificial stream and climate mitigation by the forest were essential functions for supporting the life of these crabs. Even in manmade structures for amenity, such as stream, stonewall, planted grasses and rocks, they successfully make use of such habitats. Therefore, it is evident that manmade structures can be designed multi-functionally for satisfying demands as habitat for wildlife and for the amenity of urban dwellers.

View full abstract

Green spaces at business sites potentially have important roles for biodiversity in urban ecosystems, where habitats of living organisms are greatly reduced and fragmented. Japan Business Initiative for Biodiversity (JBIB) has developed three tools consisting of the guideline that explains importance and methodology of land use for biodiversity, the land use score card that quantitatively evaluates land use, and the monitoring sheet, with which non-experts can conduct a biodiversity survey. Although these tools were developed based on ecological knowledge, it was necessary to separately evaluate whether a site with high land use score actually have high biodiversity, and how reliable the data obtained by a survey by non-experts with the monitoring sheet is. Here, we conducted biodiversity surveys by non-experts with the monitoring sheet and by experts at the same time and date at eight business sites and compared the data obtained by the two survey methods. As a result, there were positive correlations between the land use scores and α-diversity, and between the α-diversities and also the β-diversities of the non-expert and the expert surveys. These results, as far as for evaluating overall biotas by α-diversity and β-diversity, validate the tools to promote land use for biodiversity enhancement at business sites.

View full abstract