North Beach, Point Reyes National Seashore

The coastal beach and dune , also referred to as coastal strand or backshores (Kozloff and Beidleman 1994), is found along beaches and some bays. It is characterized by stretches of loose, wind swept, sandy dunes that vary in width from a few to several hundred feet. The backshores include "three subhabitats: foredune, (nearest the shore), central dune, and hinddune" (Bakker 1984; Evens 1993, p. 53).

As one might conclude, the foredunes proximity to the ocean and exposure to the wind, make it a harsh micro-climate for plant and animal life. Dominated by the introduced species of beach grass (Ammophila arenaria), yellow iceplant (Mesembryanthemum edule) and sea rocket (Cakile maritima). Compared to other habitats further from the shore, plant diversity here is very low (Bakker 1984; Barbour & Major 1984; Evens 1993; Kozloff & Beidleman 1994).

The central dune is not as harsh a subhabitat as the foredune, and includes the above mentioned species as well as beach morning glory (Calystegia soldanella), coast buckwheat (Eriogonum latifolium), coast gilia (Gilia capitata), coyote bush (Baccharis pilularis), curly-leaved monardella (Monardella undulata var. undulata), and beach sand-verbena (Abronia umbellata) (Evens 1993; Kozloff & Beidleman 1994.

The hinddune has the most protection from the elements and, therefore, the most species diversity. In addition to the species from both of the other subhabitats, it also includes: "beach pea, bush lupine, dune lupine, salt bush, beach strawberry, douglas blue grass (it occurs only on the California coast from Mendocino to Monterey Counties), mock heather, and evening primrose" (Bakker 1984; Evens p. 53, 1993; Kozloff & Beidleman 1994).

The Great Beach, also know as North and South Beach, has the most extensive dune system on the Point Reyes Peninsula (Evens 1993), and is one of the most accessible places to explore and discover the three main subhabitats of the coastal strand.

Fauna

The beach/foredune habitat is a delicate ecotone between aquatic and terrestrial life as reflected in the combination of clams, snails, anthropods, worms, birds and rodents found here. While strolling along the beach, you may have the opportunity to observe the Pacific razor clam (Siliqua patula), purple olive snail (Olivella biplicata), sand (or mole) crab (Emerita analoga), spiny mole crab (Blepharipoda occidentalis) or a red bloodworm (Euzonus mucronatus) (Kozloff 1983; McConnaughey & McConnaughey 1985).

Compared to the foredune, the species diversity of the central and hind dune becomes more readily apparent due to the variety of larger animal species. While worms and rodents like the white-footed vole (Arborimus albipes) are still present, the chances of seeing a black-tailed deer (Odocoileus columbianus), tundra swan (Cygnus columbianus), osprey (Pandion haliaetus), great blue heron (Ardea herodias) or great egret (Casmerodius albus) are increased (Ingles 1992; Kozloff 1983; McConnaughey & McConnaughey 1985).

In the evening, you may be suprised to see a black-tailed deer (Odocoileus columbianus) cautiously venture out of the forest and on to the backshores to forage. Early morning or late afternoon a great blue heron (Ardea herodias) or great egret (Casmerodius albus) may appear knee deep in a wet swale stealthfully waiting for prey. An osprey (Pandion haliaetus) casually glides overhead, seemingly unhurried, then suddenly dives like a B-52 bomber into the iceplants (Mesembryanthemum sp.), beach sand-verbena (Abronia umbellata) and beach pea (Lathyrus littoralis), back up again just as fast with a white-footed vole (Arborimus albipes) or some other dune rodent. The species diversity of the beach and dune habitats are rich and varied, and it is easy to see what is the hunter and what is the hunted (Kozloff 1983; McConnaughey & McConnaughey 1985; National Geographic Society 1983).

The coastal strand is an exposed habitat with little refuge for potential prey. How do the species that live here survive in this inhospitable environment? How are they adapted to live here?