Kay Stefanik | Assistant Director, Iowa Nutrient Research Center
Iowa was once a mosaic of prairies, wetlands, rivers, and forests. Today, Iowa looks drastically different as agriculture now dominates the landscape. Fertile prairie and wetland soils, which are ideal for row crop agriculture, have paved the way to a booming agricultural industry and led to Iowa being one of the top corn and soybean producing states in the country.
While agriculture is vital to the regional economy, all things in life come with trade-offs. The rise of agriculture came at the expense of nature. Of Iowa’s natural ecosystems, wetlands have been particularly hard hit. Prior to European settlement, wetlands made up almost 4 million acres of Iowa’s landscape. Today, there are only about 422,000 acres of wetlands remaining; this is an 89% loss in wetland habitat.
At this point, you may be wondering “why does wetland loss matter”? When a wetland is lost, we do not just lose a physical space. We also lose the wetland’s ecosystem services – the essential direct and indirect benefits that nature provides to humans. Even though wetlands are much harder to find today, the wetlands that do exist are still providing a variety of ecosystem services. These ecosystems services include:
- Flood prevention
- Water quality improvements through nutrient and sediment removal
- Wildlife habitat
- Recreational opportunities
- Food and fiber
I am in no way implying that sides need to be taken, that it is agriculture or nature. What I am suggesting is that not only can agriculture and nature coexist, but that nature can be used to improve agriculture. By protecting wetlands already on the landscape, as well as strategically creating and restoring wetland habitat, we can increase the impacts of wetland ecosystem services. Of interest in Iowa are the ability of wetlands to help with flood prevention and to improve water quality.
Flooding has become a major issue throughout Iowa over the last decade. Wetlands placed along streams and rivers have the potential to capture surface runoff before stormwater reaches the stream and can also act to hold water from a river that spills over its banks. This holding capacity prevents some of that floodwater from being immediately transported downstream. By holding floodwater in place, downstream fields and developed areas may be spared from extreme flooding events and severe economic loss.
In addition to flood prevention, wetlands also help to improve water quality. Wetlands receiving surface runoff can reduce phosphorus concentrations through the settling out of soil particles in the water column. The settled-out phosphorus becomes trapped in the wetland sediment and thus held on the landscape. Wetlands that receive water with high dissolved nitrogen concentrations, usually ground water or tile line water, can reduce nitrogen through microbial conversion to nitrogen gas. This nitrogen gas is then lost to the atmosphere, which is already about 78% nitrogen. The ability of wetlands to reduce nitrogen and phosphorus can help us meet the 45% nutrient reduction goal laid out in the Iowa Nutrient Reduction Strategy.
These wetland ecosystem services – flood prevention, water quality improvement, wildlife habitat, recreational opportunities, food, and fiber – give wetlands both instrumental and intrinsic value. Wetlands have great potential to benefit the lives of all Iowans, but only if wetlands are allowed to exist in Iowa’s landscape.