Coastal sand dunes are scattered along the California coastline from the Oregon border south to San Diego. They are dynamic habitats that are affected by wave action, tides, wind and trampling. Dunes develop where there is a substantial amount of blown, dry sand. Their formation is often aided by pioneer dune species such as beach saltbush (Atriplex leucophylla). Plants found on coastal sand dunes are mostly prostrate herbs with creeping stems and long fleshy taproots. The leaves are usually small, somewhat succulent, and often hairy and grayish in color. These features aid the plants in tolerating drought, salt stress and intense sunlight. The southern California coastal sand dunes support the rare Globose Dune Beetle and the California Legless Lizard. All dunes in California have been greatly reduced by development, off road vehicle use and exotic species invasion.