Salt Marsh

The tidal salt marsh found in and around the Peninsula is limited to the periphery of estuaries consisting of approximately 1,000 acres. "They are distributed as follows: Bolinas Lagoon (240 acres); Limantour Estero (90 acres); Drake's Estero (160 acres); Tomales Bay (510 acres)" (Evens pg. 64, 1993). Although the salt marsh of the Peninsula is almost indistiguishable from that surrounding the San Francisco Bay, there are two species in particular that are absent from the Bay: Pacific Gumplant (Grindelia stricta) and Alaska Alkali Grass (Puccinelia nutkaensis) (Evens 1993).

Even though the Peninsula's salt marshes are very similar, there are variations among them that are worth noting. For example, Limantour and Drake's marshes receive less runoff than their inland counter parts, and, therefore, are more saline. They tend to be inundated by pickleweed (Salicornia sp.) and saltgrass (Distichlis spicata) . "The upper, less saline regions of these marshes are bordered by two members of the thrift family: sea pink (Armeria maritima) and sea lavender (Limonium californicum) (Evens pg. 65, 1993). In addition, north coast bird's-beak (Cordylanthus maritimus palustris) is a rare salt marsh species that can be found in association with sea lavender (Limonium californicum) along the protected edges of these westerly marshes (Evens 1993; Kozloff 1983).

The inland and more protected marshes of Tomales Bay and Bolinas Lagoon are influenced by a wide variety of salt marsh species. At Tomales Bay, you can observe the forementioned species as well as alkali heath (Frankenia salina), common orache (Atriplex patula), saltmarsh dodder (Cuscuta salina), sea plantain (Plantago maritima), virginia pickleweed (Salicornia virginica), seaside arrowgrass (Triglochin maritima), and fleshy jaumea (Jaumea carnosa). Plant associations at Bolinas Lagoon near Pine Gulch Creek include brackish and even fresh water species gradually grading into the salt marsh. Some of these varieties include sedges (Cyperaceae sp.), rushes (Juncaceae sp.), cattails (Typhaceae sp.), alder (Alnus sp.) and willow (Salicaceae sp.) (Evens 1993; Kozloff 1983; McConnaughey & McConnaughey 1985; Shuford & Timossi 1989).

Freshwater Marsh

There are only a few scattered pockets of freshwater marshes on the Peninsula, the largest of which is Olema Marsh. Formed by the confluence of Lagunitas, Olema and Bear Valley Creeks, Olema Marsh is characterized by alder (Alnus sp.), willow (Salicaceae sp.), cattail (Typhaceae sp.) and sedge (Cyperaceae sp.). Other common species encountered in Olema Marsh include bog lupine (Lupinus polyphyllus, hedge nettle, (Stachys sp.) and marsh monkeyflower (Mimulus guttattus) (Evens 1993).

Freshwater marsh species are not always found in strict freshwater marsh habitats and may appear near the outer edges of stream fed lagoons, along creeks or in small depressed pools that appear through-out the Peninsula's landscape especially during the rainy season. The best examples of these are found at Ledum Swamp, the upper ponds of Abbott's Laggoon, Kehoe Marsh and surrounding swales, Pine Gulch Creek that feeds Bolinas Lagoon, and the northern end of Drake's and Limantour Esteros. These marshy habitats are characterized by bulrushes (Scirpus sp.), cattails (Typhaceae sp.) and sedges (Cyperaceae sp.). The rare false lily-of the-valley (Maianthemum dilatatum) can also be found at Ledum Swamp, in the wetter bog-like areas surrounding Abbott's Lagoon and at the outer Peninsula Point (Evens, 1993).

Fauna

The unique marshland habitat is one of many feeding grounds for both terrestrial and aquatic animal species. Many of the same mammal species can be found in both salt and freshwater marshes. You may even be suprised to find a raccoon (Procyon lotor psora) foraging along the edges of the marsh or a vagrant shrew (Sorex vagrans) dashing through some pickleweed. Several large birds, including the great blue heron (Ardea herodias) and great egret (Casmerodius albus), spend a considerable amount of time carefully observing and waiting for their prey.

A mother mallard (Anas platyrhynchos) and her young may paddle by, while the kill deer (Charadrius vociferus), snowy plover (Charadrius alexandrinus), pied-billed grebe (Podilymbus podiceps) and black rail (Cypseloides niger) wade and forage along the shore. You may also observe a muskrat (Ondatra zibethica) or black-tailed deer (Odocoileus columbianus) grazing around the edges (Evens 1993; McConnaughey & McConnaughey 1985).