A o Nuevo Island was still part of the mainland, an integral part of the marine terrace that to this day extends out into the sea from the foot of the Santa Cruz Mountains to the east. The westerly portion of the marine terrace is covered by sand dunes that are migrating from north to south, driven by the prevailing northwesterly winds. This 300 to 350 acre dune field is one of the few remaining active dune fields on the California coast, most of the others having been disrupted or destroyed by human activity. Here at Ano Nuevo the dunes are not being overrun by dune buggies or threatened by development, but they are changing character as a result of decreased sand availability and adjacent agricultural activity. Irrigation of nearby fields has raised the water table within the reserve and enabled the establishment of various kinds of plants.
Grasses trap the drifting grains of sand.
Wild strawberries form mats of runners across the surface, and deep-rooted willow thickets develop. As dune stabilization continues, bushy perennials like mock heather, lupine, lizardtail and coyote bush appear. Sand verbena, the succulent sea fig and colorful annuals such as evening primrose and sea rocket hug the surface of the sand and provide both cover and food for mice, rabbits and other small animals. Gray Davis, Governor.