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crb diversity

The Monterey Bay shore is more than a place to hang out on the beach or enjoy the waves. Inland from the high tide line lie ancient sand dunes, many exhibiting unique beauty and unparalled species diversity. Dunes buffer the effects of ocean waves on inland areas while they help protect the Monterey Bay National Marine Sanctuary from activity in the coastal watershed (all of the land that drains water into the ocean).

	But many of our Monterey Bay Dunes are fragile—unprotected by plant life or overrun by non-native plants, overused by people, and overbuilt. Your understanding, support, and stewardship can help protect and reclaim these fragile areas.
The Monterey Dunes follow a cycle of sand accretion (buildup) in the summer followed by erosion (tearing down by wind and water) in the winter. Sand for building dunes can come from:
slow (generations-long) weathering of granite rocks, sand and silt flowing down streams and rivers and out to sea, and sand carried on the wind from the shore and neighboring dunes.
But sand for dune building is not a never ending resource:
Irrigation diverts water that once carried sand and silt to the sea. Relocating the Salinas river mouth further interrupted this source of sand to the Monterey Dunes. Dune sand that slumps or drifts on onto roadways and paths is removed and lost to dune building. Sand mining decreases the natural flow of sand to the dunes.
	Sand verbena (at left) help stablilize dunes with their 10–20 foot long roots.
	Healthy, stable dunes rely on diversity—a wide variety of locally adapted plants—to hold irreplaceable sand in place. Native dune plants have evolved to be hardy to exposed conditions, surviving high and low temperatures, salt spray, high winds, low moisture, and low nutrient levels found in sand, which lacks humus. A native plant may:
exude sticky substances to which sand adheres, creating a coat of armor against sand and wind blast, be low-growing or very bendable to survive high winds, be adapted to sand burial, be a succulent, storing water in its leaves to conserve moisture, or grow very deep roots—up to 15-20 feet!—to tap the water table far below.

Non-native plants such as iceplant* can actually harm dunes. Though iceplant can quickly cover an area with a mat of foliage, its shallow roots mean that it will eventually be undercut by wind and tide.

iceplant fails to keep dune from walking inland

If not eradicated, iceplant's fast growing habit allows it to crowd out many young native plants that could do a better job of stabilizing the dune.

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Other threats to dunes come from people who love them!

Though dunes are attractive places to build a home or hotel, shore and dune buildings ultimately arrest the natural growth of the dunes. The sea continues to creep inland. Wind and wave scour (undercut) hardscape. Expensive measures taken to preserve a site (seawalls, other barriers) imperil other sites. Eventually, such buildings erode into the ocean.

Siting inland from the dunes while preserving and restoring the buffering dune areas can mean generations of residents and visitors can share the dune experience.

When people visiting the shore cut through and picnic in dune areas and allow their pets offleash, they damage plants, break down dune structure, and threaten the health and stability of our dune areas.

Visitors can preserve the dunes for future enjoyment by keeping to marked paths or boardwalks, picking up and packing out trash, and getting involved (like those at left) in restoration efforts.

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