Habitat-forming species such as hard corals, seagrass beds, and kelp are central to the health of marine ecosystems as they generate habitat structure, complexity, and seascapes for marine life. They are also highly vulnerable to climate change, the impacts of which can cause such vast ecosystem shifts they can no longer support the diverse array of species they once did. For adjacent coastal communities, this can mean lost tourist revenue, collapsed fisheries, and a general reduction in societal well-being.
To better prepare for these changes and understand management tools that can reduce future climate impacts, researchers in Japan and Bonaire – two places with seemingly little in common – are working towards similar goals: assessing how climate change affects tropical coral reefs in Bonaire and temperate kelp reefs in Japan.
In Bonaire, marine heatwaves brought on by climate change are causing coral bleaching and amplifying coral mortality from other causes such as disease. But in some places, protection from other pressures like water pollution, tourism, and fishing could help lessen these impacts. “Tackling climate change is a long-term and global issue. But at a local level, it can be helpful to not only evaluate how climate will impact the ecosystem, but also how the cumulative effects from local stressors could amplify climate impacts,” explains project lead, Sarah Lester with Florida State University.
The managing body for Bonaire National Marine Park (BNMP), Stichting Nationale Parken Bonaire (STINAPA), has taken many steps to protect reefs from such pressures. Now they are focused on how to improve monitoring and tools and for management responses to future bleaching events. “If there is something we can do to address climate change now- rather than just letting it happen or waiting to see what the impacts will be- we need to do it,” says Caren Eckrich, with STINAPA. “We can use the science to tell us at a local level if there are things we can do.”
The research team’s first step is to create a climate vulnerability map for the BNMP. By overlaying human activities and environmental stressors they can identify which reef areas may be most vulnerable, or resilient, to climate impacts. Understanding which reef sites are more vulnerable will help STINAPA prioritize certain management interventions now and strengthen monitoring programs at sites that are potentially more prone to bleaching or disease events.
No matter what interventions take place however, there will likely be a huge shift in the way Bonaire’s reefs look in the future. “The upside is, we’ll have the measures in place for the reefs to come back- maybe not the same or as much, but we do at least have the water quality and sustainable use in place to keep our corals going, reproducing, and thriving,” says Eckrich.
Japan’s reefs support both tropical and temperate reef communities. Temperate sites at higher latitudes generally have lower water temperatures and are dominated by kelp and large macro-algae that provide habitat for economically important fish and invertebrate species. As water temperatures increase however, kelp cover is decreasing and giving way to coral- a process called “tropicalization.” In this case, increased coral cover is a double-edge sword. “The changes are drastic, there have been whole community shifts at some of the sites in just eight years,” claims Ciara Baines, a postdoc with the University of Leeds.
To get a better understanding of how this change may impact surrounding marine life and local communities, the research team is undertaking MPAShift- a project that brings together scientific data and perspectives of the local community to understand dynamics between habitats and species shifts in marine protected areas.
“Right now, Japan’s management system is very localized. One reason for this is the diversity and complexity of Japan's marine ecosystems. As a result, it has been difficult to develop rules and systems for national level, and there’s not a coordinated national conversation about how things are changing across the country,” says Megumi Nakano, a member of The Nature Conservation Society of Japan. In many areas, laws and regulations around natural resource use are complicated and sometimes overlap in the same area. Stakeholder relationships can also be complex in that many of the resources are linked to long-standing traditions, customs, and religion. At the same time, an increasing number of people believe that change is needed to help local communities adopt the sea changes caused by climate change. Deciding how to broach these conversations poses a challenge.
“MPAShift is an attempt to get not only the scientific data about what’s changing, but a way to bring in the people who want to do something,” says Nakano. Greater knowledge of reef change can help deepen engagement between managers and local stakeholders like fishing unions, dive shops, and local municipalities. So far, researchers from the University of Leeds and University of Ryukyus have conducted visual census surveys at 51 MPA sites along Japan’s coastline. Once analyzed, these surveys will better describe changes between kelp and coral cover in the last decade and how associated fish, mollusk, and echinoderm populations may have been altered. Using environmental DNA, they can also begin to assess impacts on a microscopic scale for species of bacteria, microalgae, and microbes. The results of the analysis will be fed back to the MPAs’ management and used to initiate meetings with stakeholders.
No matter how it’s sliced, systems are changing, and in the coming decades, ecosystems look different than they do today. To better equip communities and managers with the tools they need to adapt to these changes, a mixture of science, knowledge, listening, and collaboration will be essential.