Sandy beaches and their surf zones make up a large proportion of the open coast of California and are significant components of many MPAs (Marine Protected Areas) in statewide network. Beaches and surf zones are also vital resources for society that provide recreational, cultural and economic value to local coastal communities. The rich and productive food webs of beaches, including invertebrates, fishes and birds, are closely linked to subsidies from rocky reefs and coastal waters. In MPA baseline studies, these subsidies were shown to strongly affect the diversity and abundance of invertebrate prey resources available for surf zone fish and birds in recipient beach ecosystems. The species richness and abundance of shorebirds increased with increasing wrack inputs and invertebrate prey resources suggesting they can serve as indicators of prey resources and beach ecosystem conditions. Thus, MPA protection can affect beaches and their surf zones in two ways: directly through harvest of fish, and indirectly through the influence of trophic cascades and other factors influencing the key donor ecosystems of kelp forests and rocky reefs. The strong connections of beaches to rocky habitats, especially kelp forests, represent key ecological pathways through which direct and indirect effects of MPA can cascade. Importantly, the key species, food webs, and habitats of beaches and surf zones are seriously threatened by human induced climate change via sea level rise and coastal development. The combination of high connectivity, high vulnerability and intensive human use, make sandy beaches and surf zones an important element of long-term monitoring and analyses to assess the performance of MPAs and inform the adaptive management of the State’s MPA network. Our project goals for using beach and surf zone ecosystems to address MPA performance and the evaluation questions and goals of the MLPA (Marine Life Protection Act) are twofold. We will assess direct effects of MPAs by surveying the abundance, biomass, size and diversity of surf zone fish, including harvested species and we will assess indirect effects of MPAs by exploiting the bottom up effects of the ecological connectivity of sandy beaches with kelp forests and rocky reefs thru monitoring kelp subsidies and birds on beaches. Specifically, we will monitor: 1) population size structure, abundance and diversity of ecologically and culturally important surf zone fishes that could directly respond to MPA protection: including surfperch, atherinids, flatfish, sharks, and rays, 2) abundance and diversity of birds that forage on sandy beaches and in adjacent surf zones, including shorebirds, seabirds and terrestrial birds 3) abundance and composition of kelp wrack subsidies cast onto beaches from adjacent intertidal and subtidal ecosystems, 4) human use to assess the role of MPAs as valuable resources for recreation, cultural connections, and well-being and 5) physical characteristics of sandy beaches and adjacent surf zones over time inside and outside MPAs. We will use new and existing datasets to conduct analyses across sites, regions and time to evaluate MPA performance and inform adaptive management through the lens of sandy beach and surf zone ecosystems