Gosh marshes and wetlands are useful and valuable for biodiversity, but they’re really really hard to make. Whatever can we do?
The Outside Story: Freshwater marshes are biodiversity hotspots
In addition to providing outstanding wildlife habitat, freshwater marshes perform several vital ecological functions. Marsh plants capture sediments running off the land from roads, development, and farm fields and filter out excess nutrients that would otherwise degrade water quality. These wetlands store floodwaters, control erosion, and recharge groundwater supplies. Marshes also offer recreational value and are popular places for paddling, birdwatching, hunting, and fishing.
Unfortunately, only in recent decades have people recognized the value of marshes and other wetlands and, to some extent, given them legal protection. Since European settlement, many marshes have been filled for agriculture or development, polluted by industrial run-off, or converted to ponds or lakes by dams. In some locales, there have been restoration efforts, but it is challenging to replicate a natural marsh, although beaver activity can create new marshes or change them to create other forms of wetlands.
Hey I remember spending hours next to beaver created wetlands. Watching herons and egrets and merganser and wood duck and mink and otter and frog. I remember counting how many species I saw in a single morning. And that was in the middle of a town.
Tell me more about how hard wetlands are to create?
Marsh plants have special adaptations that enable them to survive the wet conditions. For example, cattails and arrowhead can exchange gases between their emergent leaves and submerged roots. The type of vegetation that grows in a particular marsh depends on hydrology and soil. In shallow marshes, the water level varies from just a few inches to a foot deep. The soil may be always saturated, or it may be flooded periodically. Deeper marshes are permanently flooded, with large areas of open water. Marsh soils range from decomposed muck to high- organic mineral soil.
Along the edges of lakes, ponds, and rivers, marsh vegetation often grows in distinct bands, influenced by water depth and exposure. Sedges, for example, will grow in moist to saturated soil. Cattails and pickerelweed, with its distinctive stems of purple flowers, prefer standing water through most of the growing season. Aquatic bulrush and wild rice are found in deeper water.
These and several other plants, such as floating duckweed and arrow arum, form the foundation of the marsh food web. Waterfowl and other birds feed on the plants’ seeds, fruit, and vegetation, and the plants’ decomposed remains nourish a host of invertebrates such as snails, worms, crayfish, and insects. The invertebrates in turn provide food for frogs, fish, turtles, and songbirds, which feed water snakes, raccoons, herons, osprey, and bald eagles, among others. Muskrats are common marsh residents, eating the rhizomes (roots) of cattails and water lilies and building their dome-shaped winter lodges with cattail leaves. Mink slide through the lodges’ underwater entrances to prey on muskrats. Many birds, including hard-to-see bitterns, nest in marshes, and red-winged blackbirds often attach their nests to old cattail stalks.
Gosh that sounds beautiful! And familiar. I want to introduce you to a friend of mine…I’m guessing he can help.
