Management of reef-building corals, macroalgae and seagrasses in Japanese national parks: issues and suggestions

Abstract

Biodiversity plays a key role for humanity and, therefore, effective biodiversity management is essential. The biodiversity of Japanese national parks varies greatly, reflecting differences in environmental conditions such as air and water temperatures, and management is species- and community-specific. In this study, we focus on the management of reef-building corals, macroalgae and seagrasses, which shape the underwater landscape. The purpose of this study was to summarise the perception of these communities as resources in national parks, to clarify what conservation and monitoring measures are implemented for these communities, to discuss their vulnerability to climate change, and to suggest management adaptations that should be taken. Our results show that the Ministry of the Environment implemented many conservation measures for reef-building corals, such as population control of predators of reef-building corals. The number of restricted reef-building coral species was much higher than that of macroalgae and seagrass in each national park, and this pattern was more pronounced in national parks located at lower latitudes. Although macroalgae and seagrasses were listed as restricted species in some national parks, far fewer monitoring and conservation measures were implemented for these species in comparison to reef-building corals. Based on these results, we summarised the characteristics and issues of each national park. Reef-building corals are vulnerable to rising water temperatures and are expanding their distribution area northwards. Therefore, we expect that many parks will need to revise their regulated species lists and increase conservation measures in the future. In some parks, there is a gap between the present distribution of reef-building corals and their conservation management, and it is important to implement projects to fill this gap. Regarding macroalgae and seagrasses, the challenge to define their value and to implement continuous monitoring and conservation measures for these species needs to be addressed.