Climate-induced species range shift and local adaptation strategies in a temperate marine protected area, Ashizuri-Uwakai National Park, Shikoku Island, western Japan

In temperate seas, expansion of reef-building coral distribution, decline of macroalgal beds, and changes in constituent species for coral communities and/or macroalgal beds mainly due to increase in sea surface temperature have been reported. Not only mitigation but also adaptive responses are important for the measures against climate change. Consideration of adaptive measures depends on local conditions such as the degree of environmental change and industrial structure is necessary when measures are implemented. This study focused on the marine protected area (Ashizuri-Uwakai National Park in Japan) and its surrounding area. This area is characterized by a very large north-south gradient in water temperature and the distribution of corals and macroalgae along it. The purpose of this study is to consider what adaptive measures are suitable for each region and industry in response to changes in coastal ecosystems (coral community and macroalgal bed). Future (assuming the end of this century under RCP2.6 and RCP8.5 scenarios) changes in the potential distribution area of coral, macroalgae, and their consumers were projected using simulated sea surface temperature with a high-spatial resolution. After projecting the coastal ecosystem changes and assessing the contemporary use of coastal ecosystem, we give examples of what specific adaptive measures should be taken in each area for three fields, i.e., biodiversity conservation, fisheries, and tourism. Assuming the 2090s, though drastic changes in coastal ecosystem are not projected compared to the present state under RCP2.6 scenario, as coral distribution shifts north, feeding damage by crown-of-thorn starfish is projected to become a problem. Therefore, expansion of protected areas and promotion of conservation activities are major challenges for coral ecosystem conservation. On the other hand, under RCP8.5 scenario, it is important to take appropriate conservation measures for macroalgae since coral growth becomes difficult to achieve and grazing pressure on macroalgae increases due to extreme elevated water temperature. Moreover, creation of alternate or new tourism resources will be needed. This research represents projected scenarios of coastal ecosystem changes with a high spatial resolution and adaptation measures based on the changes for each municipality.