Without them, the beach would be a very different place. The sand dunes and shallow bays would probably disappear, and the wildlife we associate with the seashore would also vanish. Yet few people ever think about the plants that keep our beaches in place.
One such plant is beach grass, though the folks on Cape Cod and Cape Hatteras also call it marram grass and dune grass. It's a tough, wiry plant that sits atop and along ocean dunes and prevents the sand from blowing away in coastal breezes. American Beachgrass is the dominant Atlantic Coast and Great Lakes species, while imported European Beachgrass prevails on the West Coast.
Unlike most plants, beach grasses love sandy environments— the more sand, the better. Never mind the nutrient-poor substrate, the salt spray, the blowing sand, and the intense light; these plants can hold their own. And hold the dunes in place, too. While their roots anchor them, their horizontal rhizomes spread out beneath the sand and form a spiderweb framework.
As for wildlife, a few small rodents, toads, grasshoppers, and spiders find shelter in the beach grasses, and Horned Larks and Snow Buntings scratch out a living at times during the year, but for the most part beach grasses are alone in their sandy homes.
Meanwhile, out on the sand and sand-mud bottoms, just at the low-tide line and below, extensive beds of another invaluable grass can be found. Eelgrass is not a seaweed but a true flowering grass, with roots and cross-pollination (even if it's underwater). Extensive beds of Eelgrass do their part in preserving the environment in shallow-water bays by actually slowing down and damping water and wave movement with their fronds.
Of course, besides helping to protect the shoreline from erosion, Eelgrass beds are among the most biologically productive areas on the planet. Though Eelgrass itself is consumed by relatively few animals, mostly waterfowl like the Brant, vast numbers of marine organisms depend on it. Diatoms, sponges, bryozoans, and algae all need Eelgrass as a substrate on which to live. And feeding upon these minute creatures and plants are worms, shrimps, snails, and fishes, which also find shelter in the Eelgrass beds.
The plant is even important when it's dead. As detritus, Eelgrass feeds a variety of creatures both in the water and upon the sandy shore. Turn over a mass of stranded Eelgrass at the edge of the beach, and herds of insects and amphipods will scurry out.
Two very different grasses, beach grass and Eelgrass, but both important parts of a healthy coastal environment.