Guadalupe-Nipomo Dunes - Geography and Environment

Geography and Environment

The Guadalupe-Nipomo Dunes were formed by a combination of factors including beach sand which was blown inland by the wind and the Santa Maria River which brought sediment to the coast. Dune-building began 18,000 years ago with the Nipomo and Orcutt Mesas. This Dune System has the highest dunes on the entire western coastline of the United States. Among these, Mussel Rock Dune is the highest, measuring approximately 500 feet (150 m). Another rare geographic treasure is Oso Flaco Lake, a freshwater lake located amid the Dunes.

Even though the Guadalupe-Nipomo Dunes consist of moving sand with extremely low moisture that is seemingly deprived of nutrients, it is home to a variety of flora and fauna. There are at least 18 endangered species of plants living in the Dunes.

The dunes are separated into uplands and wetlands habitats. Uplands include the fore dunes, back dunes, and sandy beaches. The fore dunes begin at the high tide line, where only low growing plants with deep root systems (such as sand verbena) can live. The strong winds, salt spray, and massive amounts of sand make this area uninhabitable for other types of plants. The back dunes, just behind the fore dunes, are stabilized and covered with plants. The back dunes are dominated by shrub species like mock heather, dune lupine, coastal buckwheat, and blochman's senecio. The sandy beaches are a harsh environment with no plants able to survive there. The wetlands include the areas that contain water: salt marshes, fresh and brackish-water marshes, swamps, and mudflats. Plants that live there are adapted to dynamic environmental conditions including high salinity concentration and extreme temperatures.

Weeds have been introduced into the Dunes environment both purposefully and accidentally and threaten the native plant life. Various native plants are being choked out by invasive species like European beach grass.

Many species of animals can be found among the dunes. Over 200 species of birds live there, such as the western snowy plover, American peregrine falcon, California brown pelican, and California least tern. Other animals also depend on the dunes such as the california red-legged frog, coast garter snake, deer, black bear, bobcats, and mountain lions. Beetles, butterflies, lizards, saltwater and freshwater fish inhabit the dunes as well.