Marine protected areas (MPAs) have gained attention as a conservation tool for enhancing ecosystem resilience to climate change. However, empirical evidence explicitly linking MPAs to enhanced ecological resilience is limited and mixed. To better understand whether MPAs can buffer climate impacts, we tested the resistance and recovery of marine communities to the 2014–2016 Northeast Pacific heatwave in the largest scientifically designed MPA network in the world off the coast of California, United States.

California’s iconic underwater forests are under threat from climate change. From 2014-2019, more than 95% of the bull kelp off our state’s northern coastline disappeared following a record-breaking marine heat wave and an explosion in kelp-eating purple sea urchin populations. Portions of California’s central and south coasts, such as the Monterey Peninsula, have also experienced severe declines in kelp. These die-offs have had serious impacts on coastal communities – closing fisheries, shuttering dive shops, and affecting tribal members, divers, and fishermen across the state.