While they may not be wet all seasons of the year, wetlands are a vibrant and vital part of our landscape year round. And now that the calendar has turned to May, we’ll be celebrating wetlands all month long as part of American Wetlands Month, recognizing the importance of wetlands across our great nation!
Wetlands go by a variety of different names and identities depending on where you’re located! Tidal wetlands, where sea water and fresh water mix, are common along our nation’s coastlines. In Iowa, our wetlands are obviously non-tidal. Here, wetlands can be found on floodplains along rivers and streams (riparian or riverine wetlands), along the margins of lakes and ponds (lacustrine wetlands) or inland — individual depressions surrounded by dry land (like the prairie potholes — the most common on our landscape).
Whether we call it a swamp, a bog, a marsh, a pothole, or a slough, wetlands evoke a sense of mystery and beauty. Think about how frequently we use wetlands terms in the English language. Consider the concept of being “swamped” at work or “getting bogged down” with a home improvement project. These literary analogies create an imagery of wet, mucky soil, or getting stuck – vivid imagery of what some wetland environments can be like!
What exactly makes it a wetland?
Wetlands are transition zones where the land meets the water – diverse ecosystems where the water table is at or near the surface, or the land is covered by shallow water. While standing water may not be visible above the land surface, the area may still be classified as a wetland due to the unique hydrology, soil, and vegetation found there.
The Clean Water Act defines wetlands as “those areas that are inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar areas.”
What makes wetlands unique?
Regardless of name and geographic location, all wetlands are characterized by three distinct attributes…
The area is periodically inundated or saturated to the surface at some time during the growing season. Put simply, water is present (whether visible to the bare eye or not).
Wetlands are characterized by having hydric soils. Hydric soils are permanently or seasonally saturated by water. Because the soil pore spaces are saturated/filled with water, oxygen is not present; thus, these soils are anaerobic. Hydric soils are identified primarily by their color.
The plants that live in and around wetlands are highly water-tolerant. They are often referred to as “hydrophytes” or “hydrophytic vegetation.” Put simply, these plants don’t just survive, they thrive in wet environments!
Some wetland plants are submergent, with most of their structure below the surface of the water. Others are emergent, with part of their shoots or leaves above the water’s surface, like the common arrowhead (Sagittaria latifolia) shown above.
When determining whether an area of land may possess wetland characteristics, the larger plant community is evaluated, including trees, shrubs and herbaceous plants. Even if the area was drained or altered in the past, the endemic wetland seed bank is often still present.
Stay tuned throughout the month of May for weekly blog posts celebrating all things wetlands – how these vital ecosystems function, their many roles on the landscape, and the unique resources available to help teach young people (and the young at heart!) all about wetlands!