Salt Marsh Plant #2: Pacific Cordgrass - Spartina foliosa

Spartina foliosa

At the very lowest part of the California coastal salt marsh is a grass species that is unique in more ways than one. Spartina foliosa, also known as Pacific or California Cordgrass, will grow in fields where it is allowed (if it is not out-competed by plants in the middle marsh or limited by nitrogen or deep elevation in the mudflat). With no other plant able to thrive where it has rooted, the swath of subtle green borders the marsh, seemingly protecting it from the water at a low tide. As the tide rises the spear tips of the Cordgrass gradually disappear but for a while all you will see is a water bed of green spikes protruding as the creeping ocean threatens to dominate.

It is typical to break up a coastal salt marsh into three areas: the low, middle and high marsh; each with its own level of tidal influence that dictates the flora and subsequent fauna that live there. Generally speaking, this demarcation allows hardy plants with high alkaline (salt) invulnerability to grow in the upper marsh, succulents and creeping rhizomatic (a rhizome is an underground stem that puts out roots and shoots, helping the plant grow in large colonies) plants in the middle and only Spartina foliosa in the low marsh. There is some interchange and mixing but that just fortunately adds to the beautiful pastiche of habitat for an interested ecologist – and I’m sure an insect or two.

The flowering season is now, like most marsh plants, and the grass is neither as tall nor as robust as it will be in the next couple months. The State and Federally Endangered Light-Footed Clapper Rail (Rallus longirostris levipes) profits surprisingly well from the health and virility of this plant as it creates its nest within the Cordgrass; it offers both a dense cover from raptors and a mooring opportunity with the fluctuating tides (you wouldn’t want your babies floating away from you, would you?). The Rails will lay about a half dozen eggs within their Cordgrass nests and nurture them throughout the summer.

Pacific Cordgrass is a flowering plant and does distribute seed (sexual reproduction) but most of its propagation occurs clonally or rhizomatically (asexual reproduction). This spread of grass captures sediment and builds mudflats (a process called accretion) and as one website puts it, helps put the ‘land’ in ‘wetland.’

Wetlands are an impacted habitat with many factors affecting their health and stability. Pacific Cordgrass is not immune from these impacts and unfortunately is susceptible to its own unique problems: it has difficulty setting its seed due to low germination rates, it is dependent upon nitrogen levels in the soil and it has a nasty East Coast competitor/cousin fighting for turf. This highly invasive non-native invader, Spartina alterniflora, is stronger and taller and built for dominating large areas of coastal wetland – similar to those found in its native environment of the East Coast. When faced with the geographically smaller wetlands of the Pacific, alterniflora bullies our foliosa. This can have detrimental results that destroy necessary mudflat (prime invertebrate habitat and subsequent foraging grounds for wetland water fowl) and can molest the natural water flow into a wetland.

Some of my most dramatic memories studying wetlands have occurred in healthy Spartina fields. I have seen Clapper Rails and their nests, a Harrier hawk bully a Great Egret and a horde of Purple Shore Crabs emerge from the grass as if exiting an aqueous forest. However, the most memorable instance occurred about two years ago. Right after the break of dawn one August morning, my colleague and I took a boat out during a mid tide. We were in the middle of the Los Cerritos Wetlands and attached to the tips of Cordgrass sticking out of the water were spider-webs covered in dew from the lazy marine layer. It created a crystalline field of sparkling webbing bordered by green lance-like leaves. The sun burned through the fog gently and the marsh subtly radiated a hazy aura through the gossamer. It was breathtaking. As the tide rose, our attention was drawn downward and we witnessed a mass emigration of spiders walking on the delicate film of the water, leaving their soon-to-be-submerged homes, searching for any relatively dry substrate. Needless to say, we found a few refugees in our boat. I have yet to identify these special nomadic creatures and as much as I would like to know them, it just adds to the mystery of this place for me.

~Taylor