Designing marine protected areas in the fight against climate change

An international team has developed the first comprehensive framework for designing networks of marine protected areas that will help vulnerable species survive as climate change drives habitat loss.

on a piece of paper Published Inside an earthResearchers have outlined guidelines for governments to provide long-distance larval drifters such as sea urchins and lobsters, as well as migratory species such as turtles and sharks, with protected stops in coastal corridors.

Led by Stanford marine conservation scientist Nur Arafeh-Dalmau, the team included 50 scientists and practitioners from academia, conservation organizations and management agencies from the United States, Mexico and Australia.

The guidelines come at an important time as every country in the world has committed to protecting 30% of the world’s land and seas by 2030. Marine protected areas and similar conservation measures on land connect habitats that have been degraded by generations of human development or destroyed by wildfires. and heat waves.

„Until now, marine protected areas have been designed for biodiversity conservation, but not necessarily for climate resilience,” said Arafe-Dalmau, a postdoctoral scholar in the marine department at Stanford’s Doyer School of Sustainability and an honorary fellow at the University of Queensland. . „They are vulnerable to climate impacts but are not designed to withstand them.”

Enter the Southern California Bight

As a case study, the authors used the 21 biological and physical guidelines presented in their framework to map giant kelp ecosystems and protections for species across the Southern California Bight. This wide area contrasts with the gradual curving of the southern course of the California coast, which curves southeastward on the peninsula of Baja California, Mexico.

Here, giant kelp forests provide nursery areas, shelter from predators and storms, and food for hundreds of commercially and culturally valuable species. In recent years, ocean heat waves and prolonged periods of low dissolved oxygen have led to the decline of commercially valuable fisheries such as jumbo squid and abalone, affecting the livelihoods of local communities.

Although Baja California is home to large marine protected areas, and in the design process, less than 1% of coastal waters are fully protected and prohibit extractive activities such as fishing or drilling. In California, marine protected areas account for 16% of state waters, half of which are fully protected. According to the California Department of Fish and Wildlife, these protected waters form the largest ecologically connected marine protected area network in the world.

However, the network does not account for how the species moves between the United States and Mexico, meaning that even if a country protects the species’ nurseries, those benefits are lost if it makes a short move into a neighboring country where larvae can settle and grow. Adults.

„We’ve designed a systematic approach that helps resource managers stay ahead of the curve and anticipate rather than react to climate change,” said co-lead author Adrien Munguia Vega, a genetics researcher at the University of Arizona and the Applied Genomics Laboratory in Mexico.

„It shows how entire marine ecosystems and the species that live in them are connected by ocean currents that don’t stop at international borders. Therefore, we need concerted efforts and protections across political borders.”

Integrating climate

Government agencies responsible for establishing new marine protected areas typically refer to biological and physical criteria developed by scientists over the past two decades. The study authors expanded these guidelines from acknowledging the need to address climate adaptations to openly planning how different future climate scenarios might play out.

For example, conservation planners today try to give threatened species enough time to recover from overfishing or habitat loss. The new framework requires marine resource managers to assess whether the proposed timelines will help vulnerable species recover over the next decade or even century.

Management officials are currently considering whether protected areas include the full range of habitats that regional species need to thrive. In the Southern California Bight, they may prioritize protecting a variety of sandy beaches, waves, rocky cliffs, and kelp forests. In addition to habitat diversity, researchers prioritized habitat stability, or the presence of habitat over time.

Considered „climate refugia,” these habitats often experience natural temperature changes from local currents and can provide stable respite for species facing extreme heat shocks.

„Climate extremes do not stop at the boundaries of a marine protected area,” said Fiorenza Micheli, chair of the Department of Oceanography and co-director of the Center for Ocean Solutions. „If California’s network of marine protected areas were designed with climate in mind, it would be different.”

Putting the framework into practice

Researchers analyzed decades of satellite imagery to map the persistence of giant kelp along 1,678 miles (2,700 kilometers) of continuous coastline in the Southern California Bight and calculate how many safe havens they provide for sea cucumbers, sea urchins, abalone and abalone spawning larvae. .

They found that under current conservation plans, ocean heat waves expected over the next 50 years would fragment suitable habitat for these larvae. Ecological connectivity, a measure of an animal’s ability to move freely from place to place, would drop by about half, while population density could drop by as much as 90%, the authors estimate. This could mean smaller gene pools and a greater risk of population decline.

Conventional assessment methods prioritize the protection of areas with high numbers of kelp species. The new framework, in contrast, identified sites where kelp had a higher chance of survival and were more likely to provide stable habitat for other marine species to reproduce. They suggested a series of protected areas Connecting isolated people Like the beads of a Southern California bead necklace.

„This stair-stepping strategy is very cost-effective and affordable for everyone,” said Arafe-Dalamu, who documented it. Mexico’s Worst Ocean Heat Wave From 2014 to 2016. „If you’re protecting important areas, some areas may need to be protected.” Also, cooperation between countries will strengthen research capacity and diplomacy.

„We have the information and tools to design and implement marine defenses that account for climate change transparently and proactively,” Micheli said. „Now is the time to understand where we are investing strategically to expand and strengthen conservation so these ecosystems have a future.”