A wetland is a transition zone between dry land and open water. Because of this mix of two environments, wetlands serve as a rich source of animal and plant life. Contrary to the popular assumption, wetlands do not have to be wet 12 months a year – just a few weeks of continuous wetness is enough to label an area as a wetland. Scientists study how much water flows into a wetland and how long the water remains, a field called hydrology. They look closely at how much oxygen is dissolved in the water. A lack of oxygen in the soil is called anaerobiosis, and it can kill plant life.
Waterlogged, or hydric, soils are typically gray with reddish stains. Different plant species have adapted to hydric soils in different ways. Reeds and rushes have evolved to use oxygen efficiently, pushing down oxygen from the atmosphere into the root zone. When you order flowers from a shop or online, you typically are not getting specimens that live in wetlands, as these areas are usually protected. That’s because they provide a number of important ecological functions:
- Water Filtration – plants and soils in wetlands clean the water before it joins rivers or groundwater.
- Good Eating – coastal wetlands are important for the reproduction of many species of fish, crab and other shellfish. In Texas alone, over $400 million in wholesale commercial fishing activity is supported by wetlands, keeping over 30,000 residents employed.
- Wildlife: It’s not just the fish that depend on wetlands – small mammals and birds live there as well. Birds use wetlands as part of their migration patterns.
- Floods: Wetlands serve as flood buffers by retaining excess water. If you destroy a wetland, you may worsen downstream flooding.
- Erosion: Reduced erosion and more stable river banks occur due to wetlands.
- Fun: A lot of recreation is supported by wetlands, including bird-watching, hunting and fishing.
You must receive a permit from the Army Corps of Engineers before you are allowed to drain or fill a wetland. Normally, if a wetland has to be compromised for some reason, an offsetting amount of new wetland is constructed. Nonetheless, humans are the biggest threats to wetlands, through such activities as agriculture, industrial development, and real-estate development. Urban sprawl is the single biggest encroacher upon wetlands. Also, seawater wetlands are sometimes threatened by drilling for oil and gas. Estuary wetlands are complex because they rely on a mix of fresh and salt water. If the freshwater component is threatened, the whole estuary can suffer.