Evaluation of the Nansei Shoto Ecoregion

Geographical location:

Asia/Pacific > East Asia > Japan

An Amami rabbit (Pentalagus funessi), endemic species of Nansei Shoto. Japan.
© WWF Japan / Haruko Ozaki

Summary

Nansei Shoto, a chain of sub-tropical islands located in the Southern end of Japan, is rich in endemic and sub-endemic fauna and flora. From a biodiversity conservation perspective, it is extremely important to conserve this archipelago.

WWF has been active in conducting various projects about coral reefs, endemic species, local awareness and education, tidal flats and forest in the region since the mid 1980s.

To improve its activities and further promote conservation, WWF is preparing a particpatory approach, which involves the drawing up of a biodiversity vision, conservation plans for priority areas, and implementation of a geographical information system (GIS).

Background

Nansei Shoto is a chain of islands situated in the Southern end of the Japanese archipelago. It includes all the Japanese islands lying to the South and is divided into 7 sub-island groups - Satsunan, Tokara, Amami, Okinawa, Senkaku, Daito, Sakishima from North to South.

Over the course of 10 million years, Nansei Shoto's shape was changed as it connected and disconnected from the Eurasian continent, Taiwan and Japan, due to sea level changes and vigorous diastrophism.

The boundary of 2 zoogeographical regions separating the Northern area and Tropical area is fixed on Nansei Shoto, (i.e. Palearctic in the North and Oriental in the South). Each part not only has its own characteristics but also has strong influences on the other.

Most fauna of Nansei Shoto are either endemic or sub-endemic species and of old origin, e.g. Iriomote cat (Prionailurus iriomotensis), Amami rabbit (Pentalagus funessi), Ryukyu longhaired rat (Diplothrix legata).These characteristics are a result of the long geographical history of Nansei Shoto, especially its long history as isolated islands after the Quarternary era. The sea level changes and diastrophism provided species of other regions with access to Nansei Shoto and allowed them time to evolve.

However, this unique nature was gradually eroded over the last century. World War II devastated the forest on Okinawa Island, and, after the war, military drills have taken place in the areas which are home to endangered species. Massive developments for social infrastructure and agriculture have been taking place in many parts of the archipelago since 1972 when Okinawa was returned to Japan. Forests are being cut for logging, highways, farms, and dams. Coral reefs and tidal flats are reclaimed and red soil run-off from farms and construction sites upstream are choking the rivers and coral reefs downstream.

A further problem is caused by the spread of invasive species which threaten endemic species in many parts of the archipelago.

To address these problems, WWF, since its foundation in 1971, has supported individuals and groups dealing with conservation activities and research in the region, and conducted many conservation activities for the Shiraho coral lagoon. These include opposition to an airport construction, local awareness in the Amami Island and conservation of dugongs in Okinawa Island.

To further improve and refine its activities, WWF aims to establish a biodiversity vision to review the activities and make conservation plans for each of the priority areas with indicators of present species.

Taking into consideration the rich biodiversity and conservation value of Nansei Shoto, the Japanese government has selected the archipelago as a candidate site for World Heritage listing. Before it can be registered, numerous problems must be addressed, including insufficient protected area and measures against invasive species. This project is expected to improve local conservation status.

Objectives

- Select priority conservation areas from a biodiversity perspective.

- Prepare a 50-year biodiversity vision for the Nansei Shoto ecoregion.

- Draw up conservation and management plans for priority areas based on this biodiversity vision.

Solution

- Formation of a working group (of specialists and WWF).

- Study of criteria of important species.

- Selection of important indicator species.

- Addition of detailed information to selected species (e.g. distribution, ecology).

- Preparation of a geographic information system (GIS).

- Selection of important indicator species based on GIS information (by September 2007).

- Addition of supplementary information and field study.

- Literature survey on environment and threats to wildlife.

- Selection of priority areas based on GIS information, on habitats of important indicator species (by June 2008).

- Discussion and decision on the biodiversity vision by the working group and local stakeholders based on GIS information (by June 2008).

- Discussion on conservation and management plan based on GIS information (in 2009).

Achievement

By March 2007

- Key researchers and important species were identified and listed.

- Literature survey commenced.

- List of candidates (researchers, government officials, NGO staff, GIS specialists) for the working group was made and members selected.

- Action plan was made (target, candidates of important indicator species, criteria of biodiversity evaluation, data format).

- Relevant information was gathered from the group members.

By March 2008

- GIS mapping of critical habitats for indicator species colonies commenced.

- System and procedure to evaluate priority coral community areas established.

- Development of methodologies to assess possibilities of coral distribution ordered.

- Hearing survey in each critical area implemented (about 1000 locations).

- Discussion to select high priority conservation regions ordered.

- Site surveys commenced.

- In March 2008 the project surveyors captured five Ryukyu spiny rat (Johnson, 1946) for the first time in 30 years.

By March 2009

- A map showing coral prioirty areas (healthy and important coral communities, CPAs) was produced and made public. It was covered by the media like the National Geographic (Japanese edition), Asahi (2 articles).

- Presented the map at the 11th International Coral Reef Symposium, held in Fort Lauderdale, Florida USA between July 7 and 11, 2008 and at the International Coral Reef Marine Protected Area Network Meeting (4th ICRI East Asia Regional Workshop) held in Tokyo between November 17 and 19, 2008.

- WWF Japan’s research found a new species of crustacea (Thermosbaenacea,Halosbaena) in Nansei Shoto. It was covered by 23 local newspapers including Nikkei.

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