Adaptive Recovery with a Coastal Ecotone
- Shinhama, Japan

Tsunami and power of nature

The coastal ecotone is defined as a transition zone that integrates shallow water, shoreline, dunes, reefs, coastal forests, waterways and canals, seawalls and roads, and agricultural land. The coastal ecotone that stretches across the Sendai Plain is a complex and unique landscape created through the process of destruction and revival by repeated floods and tsunamis over the past several centuries. For about 400 years, people living by the sea have been planting pine trees, digging waterways, and gradually adding to the natural environment to build a foundation for their lives. As a result, the coastal ecotone is a beautiful harmonious landscape where man-made structures have become part of nature.

The tsunami that followed the 2011 Great East Japan Earthquake destroyed many coastal ecosystems in the Northeast region of Japan. Minami-Gamou Monitoring Network, the researcher group started a vegetation survey at the ecotone in Shinhama 3 months after the tsunami. Interestingly, the ecosystems seemed to be recovering there. The pine grove in Shinhama’s coastal ecotone managed to survive. The once-devastated ecotone of Shinhama was rapidly regaining its original beauty, with wildlife and habitats recovering autonomously, faster, and more expansively than predicted. However, they were concerned that the new seawall development plan would eliminate ecotones. Local people were not initially aware of the importance of ecosystem restoration and rather desired the seawall would be constructed soon. The researchers faced the dilemma: saving lives versus ecosystem conservation.

A collective endeavor for ecotone restoration

After a painstaking discussion with the government, they successfully achieved the pilot monitoring site of ecotone in Shinhama. For example, prior to the construction of the base embankment, they had an experimental area, where they were able to continue vegetation surveys. This required the construction of a partial bend in the seawall to preserve the ecotone site. Consideration was also given to the construction of coastal embankments to restore the coastal forest, which is full of diverse local species and ecosystem services.

In addition, researchers informed local people of the importance of the coastal ecosystem. Thanks to their engagement, local people came to realize the ecological, cultural, and historical values of their local ecosystems and began to support the coastal ecotone. Then, they started the locally-led activities to learn more by themselves and disseminate the value of nature to the general public. Their collective voice prompted the government to realize the ecotone project in Shinhama. Likewise, the local government officers greatly supported the activities led by local people, and their attitude gave a good impression to local people.

Harmony of green and gray infrastructures

Today, the ecotone in Shinahama exists in harmony with gray infrastructures. The various ecosystems in the ecotone perform a variety of benefits for the local communities such as tide and sand control, tsunami and flood mitigation, water purification, supply of fuel and fertilizer such as firewood and fallen leaves, and creation of a beautiful landscape. The ecotone forms sand dunes, forests, and wetlands that absorb the impact of coastal hazards such as tsunami and storm surges and break stormy wind. It plays an important role in protecting farmland and residential areas from disasters. The seawall in front was set back so that the ecotone could be left as is, and the man-made embankments supplemented the ecotone’s DRR effect. This mixture of green and grey in Shinhama poses a new recovery model that incorporates nature wisely rather than uniformly build man-made structures so that people can continue to receive the ecosystem services.

Adaptive recovery

One of the main characteristics of the coastal ecotone is its flexibility to accept external disturbances such as natural disasters to some extent. Since ancient times, this region has been frequently hit by tsunamis, but each time it has recovered through the healing power of nature. Given that the impact of coastal disasters will increase as climate change becomes more serious, ecotones are a good way to adapt, as they can accept and flexibly respond to external forces. Although they are somewhat inferior to grey infrastructures in terms of disaster risk reduction, they are cost-effective when considering the benefits to biodiversity conservation and to the people living in coastal areas. As the threat of disasters increases, seawalls will have to be raised, which is costly and labor-intensive, while ecotones can continue to exist while accepting the impacts.

In conclusion, the coastal ecotone in Shinhama is a good practice because of the fact that the restoration and reconstruction project was carried out without interfering with the recovery process of these organisms and their habitats. This case proposes a smart model for ecotone-based recovery design. Since the tsunami, there have been discussions about harmonious and synergistic development enabling reconstruction of residents' daily lives and using ecosystems to create public interest functions