Habitat Snapshots

Salt Marshes: Salt marshes are types of wetlands that look like grassy meadows and form along coastal shorelines or in the shallow parts of estuaries. Most common along the Atlantic coast, they benefit from nutrients delivered by the tides, waves and nearby watersheds. The most common plants found here are the salt or cord grasses. This tough plant forms dense root systems and can survive being submerged under salty water. It even secretes excess salt through special glands. These plants are the main producers of the marsh, fuelling complex food webs. Fungi and bacteria break down dead plant material and are, in turn, eaten by filter feeders such as worms and mollusks. Fish eat the filter feeders, and birds and mammals eat the fish.

Besides being important biologically productive habitats, these wetlands have many other values:

Coastal wetlands are storm buffers, absorbing the energy of high waves and storms that might destroy shorelines, roads and properties.
Wetlands are nature’s filters. They filter out toxins and remove chemical waste from coastal waters. Wetland plants such as marsh grasses (Spartina alterniflora and Spartina patens) use up, tie up and filter out some of the detergents, paints, pesticides, herbicides and sewage that we have put into the environment all the way along the watershed.
Coastal wetlands are crucial pit stops for many species of migratory birds that need to feed and rest during their transcontinental travels.

Tidal Flats: Tidal flats of mud or sand are found along all coasts and often extend a kilometre or more in width at low tide. While this habitat often appears abandoned and lifeless, a close look shows thousands of organisms per square metre of mud — and that’s without a microscope! The abundance of mollusks, worms and tube-building amphipods supports millions of shorebirds every year. The mudflats of the Bay of Fundy alone host an estimated 50 to 95 per cent of the world’s semipalmated sandpipers when hunger strikes.

Tidal flats provide food for a number of other species, too — including humans. Mudflats are important habitat to many kinds of fish that move in during high tide to feed. Many species of migratory shorebirds rely on coastal mudflats for feeding and resting during their transcontinental travels, such as semipalmated sandpipers. Mudflats provide food and jobs for people who harvest clams, shad, bait worms and striped bass.

Rocky Shores: Rocky shores are formed by geologic processes, such as glacial activity and earthquakes, and continue to be sculpted over time by wind and wave action. Wind, waves, ice, salt and temperature all play a role in breaking down the rock into its mineral components.

The plants and animals that make this habitat home must contend with the triple challenge of pounding waves, changing water levels from tides, and staying put in a rock-hard environment. There is no mud or soil for rooting or burrowing, so plants and animals alike have adapted unique ways of anchoring themselves.Seaweed attaches to rock with root-like structures called holdfasts. Some animals produce glue-like substances that keep them in place while others use specially modified “feet.”

One of the harshest areas of a rocky shore is the intertidal zone, where creatures must survive alternately being covered in churning water for several hours, then being left high and dry. These are excellent places to explore at low tide when you might find sea anemones, crabs, mussels, oysters, whelks, sea stars, sea urchins and a host of other creatures.

Healthy rocky shores are important for many reasons:

Wave action breaks down the rock and adds minerals to the water, which act as nutrients for plant growth.
Rocky shores provide food for humans. For example, rockweed, mussels and sea urchins are harvested directly from the rock.
Many species of plants and animals make the rocky shore their home. Some, like the periwinkle, live here year-round. Others, like the harlequin duck, only spend part of the year, while still others, such as herring, live somewhere else but visit regularly to feed.

Beaches and Dunes: Coastal beaches provide humans with access to the ocean. Besides being great places for us, these fragile ecosystems are habitat for hardy species of plants and animals.
Most of today’s beaches are the work of glaciers that ground rocks into fine sand particles thousands of years ago. As the glaciers melted, the flowing water delivered the sand particles to the coast, forming beaches. Today, wind, waves, ice and rain all push and sculpt the sand so that the beach is constantly on the move. Dunes form inland from the beach as the sand dries out and blows with the wind. Once the dry sand is deposited beyond the reach of waves, it accumulates and forms ridges. Wind continues to move the sand around, sometimes causing the dunes to “roam” over time.

It is not easy for plants to get a foothold on this dry and shifting environment. Once plants are established, they have the added challenge of retaining moisture in a dry environment. Plants have adapted a number of strategies to deal with their dry environment. Some produce small, waxy, hairy or even leathery leaves to reduce moisture loss through the surface of the leaf. Others send down long taproots, while still others have developed the ability to absorb extra moisture from the ocean spray.

Healthy beach habitats are important feeding and resting areas for shorebirds, especially during migration. They also provide nesting habitat for many bird species including the piping plover, spotted sandpiper, common tern, red-breasted merganser and several species of gulls.

Peatlands: Peatlands are types of wetlands populated by low shrubby vegetation on a base of peat. These habitats are usually acidic and low in nutrients — not the best environment for plants to grow. Some plants like the pitcher plant have adapted by evolving the ability to trap and digest insects.

Bogs and fens are types of peatlands. Bogs tend to be more acidic than fens and plant species differ. Sphagnum moss is the most common plant in bogs, while sedges dominate fens. Large areas of bogs and fens are called muskegs. Coastal peatlands are mainly found in the north. For example, James Bay and Hudson Bay have huge coastal peatlands.

Like all wetlands, peatlands are important coastal areas. Migrating birds, mink, otters and moose are among the animals that use peatlands. Like marshes, peatlands filter out toxins and remove chemical waste from coastal waters.

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