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The island laboratory concept has long been an important construct in island archaeology, with an emphasis on human biogeography and issues of isolation, connectivity, interaction, evolution, and extinction. The Pacific Coast of Alta and Baja California contains several offshore islands that offer a framework for evaluating a variety of cultural and ecological issues. The California Islands include large islands (>100 km2) with abundant resources that were attractive to ancient people for 13,000 years and numerous small islands (5 km2 in area or less), many of which contain evidence of human occupation for centuries to millennia. Most of these small islands have seen limited archaeological research and often are presumed to have been marginal locations for past human settlement. Today, small islands from San Francisco Bay to Baja California provide key habitat for endemic species, breeding seabirds and marine mammals, and rare plants. Here, we review the archaeology of small islands on California's outer coast, focusing on paleogeography, human settlement dynamics, and ecology and biodiversity. Synthesis of archaeological and environmental data demonstrate the utility of small islands as model systems for evaluating changes in island ecology. [ABSTRACT FROM AUTHOR]

Sea-level rise during the late Pleistocene and early Holocene inundated nearshore areas in many parts of the world, producing drastic changes in local ecosystems and obscuring significant portions of the archeological record. Although global forces are at play, the effects of sea-level rise are highly localized due to variability in glacial isostatic adjustment (GIA) effects. Interpretations of coastal paleoecology and archeology require reliable estimates of ancient shorelines that account for GIA effects. Here we build on previous models for California's Northern Channel Islands, producing more accurate late Pleistocene and Holocene paleogeographic reconstructions adjusted for regional GIA variability. This region has contributed significantly to our understanding of early New World coastal foragers. Sea level that was about 80–85 m lower than present at the time of the first known human occupation brought about a landscape and ecology substantially different than today. During the late Pleistocene, large tracts of coastal lowlands were exposed, while a colder, wetter climate and fluctuating marine conditions interacted with rapidly evolving littoral environments. At the close of the Pleistocene and start of the Holocene, people in coastal California faced shrinking land, intertidal, and subtidal zones, with important implications for resource availability and distribution. [ABSTRACT FROM AUTHOR]

The northern Pacific Coast is an important area for understanding human colonization of the Americas, but Late Pleistocene coastal sites are rare and interglacial sea level rise has inundated the continental shelf and the primary areas where Paleocoastal archaeological sites are likely to occur. Here we outline a terrestrial archaeological survey project designed to identify Paleocoastal sites on Santa Rosa Island, California. Using reconstructions of ancient shorelines and paleogeography, we predicted that sites might be found where lithic resources, freshwater springs, caves or rockshelters, and strategic vistas drew Paleocoastal peoples into the island interior. We identified nine new Paleocoastal sites, including four radiocarbon dated to >11,000 CAL B.P. that are among the oldest sites on North America's Pacific coast. Our targeted survey demonstrates an important technique for investigating island and coastal settings where sea level rise remains a significant challenge for locating early sites. [ABSTRACT FROM AUTHOR]