If you have been keeping up with my blog posts this month, then you should already have a basic understanding of the import habitat and diverse ecosystem that wetlands provide. Ecosystem services or goods contribute to human’s well-being. The unique and dynamic community within wetlands provides various services and goods directly and indirectly to us. This week I will be discussing the top five ecosystem services that wetlands provide, methods that help us to monetize these services and goods, and why conservation should be important to us when making development decisions.

List of Wetland Ecosystem Services:

• Habitat and Biodiversity: This is important to commercial and recreational fisheries
• Tourism and Recreational Activities: both for nature and hunting/fishing
• Nutrient, soil, and sediment regulation: Helps reduce the cost of water purification and prevent erosion
• Food Source
• Water Supply
• Air Supply
• Storm Surge and Runoff Mitigation
• Carbon Sequestration
• Migration Stopovers (transitional sites)
• Nursery/Nesting Location
• Aesthetics and Culture

Top 5

These ecosystem services can be condensed into a list of 5 major services that wetlands provide

1. Pollutant filtration

Wetlands act as a natural water filtration system. Studies have found that wetlands in South Carolina remove the same quantity of pollutants from the surrounding watershed as a water treatment plant. Tree roots remove nutrients from ground water and store them in wood and leaves. Other vegetation can trap and remove particles from storms. Bacteria convert the harmful nitrate in watershed into nitrogen gas in a process called de-nitrification. Soils in wetlands can also retain nitrate and other harmful toxins. The economic value estimated for nitrogen removal was $188/kilogram for the Houston-Galveston region.

2. Air Quality

Trees are important in providing quality air. Trees can absorb gases like sulfur dioxide and nitrogen oxide, which are components of acid rain, and carbon monoxide. All these gases can be toxic to humans. It was estimated that the trees in the Houston-Galveston wetlands provided $312/acre/year of human health benefits by just improving the air quality.

3. Fresh Water Supply

Wetlands act as a local freshwater reservoir. Freshwater of course is vital to our lives and is important during drought years. Wetlands retain much more rainfall than any paved surfaces. Wetland reservoirs are worth more than an estimated $9,000/acre/year.

4. Storm Surge and Erosion Mitigation

Vegetation in wetlands can act to stabilize sediment and slow water’s movement, reducing erosion potential. Wetlands efficiently capture water and sediments reducing flood damages by an estimated $8,000/acre/year. Wetlands also act as a buffer to the uplands from winds and ocean waves including those from hurricane storms. Wetlands provide a levee obviously more cost effective than any constructed levee. It has been estimated that nationwide wetlands can reduce hurricane damage by well over $3,800/acre/year. I suspect this number is low and has most likely grown.

5. Climate Regulation

As I hope you are already aware, climate change is taking a massive economic toll on us and is expecting to only increase as climate change progresses. If the current trend to progress climate change continues, then the impact of climate change could cost the US over $3.6 trillion each year by 2100.  Wetlands help to remove and store carbon dioxide and other greenhouse gases from the atmosphere in carbon-based plant matter. Wetlands can store 81-216 metric tons of carbon per acre. Annually, $2 of damage can be prevented with each metric ton of carbon that is removed from the atmosphere. This is $162-432 of damage prevented per acre.

Note: This number is for wetlands only! Forests and other ecosystems also help to regulate carbon in our atmosphere and could help prevent climate change damages.

Methods to Monetize Services

There are two main methods for understanding and calculating the monetary value an ecosystem has. The first method is called Replacement Cost. This method looks first at what the ecosystem provides naturally. Then an estimated cost of what will have to be used to replace this natural service if it no longer occurs is calculated. In Summary, the value is determined by how much money it would take to replace the ecosystem services naturally occurring; however, these estimates can be an overstatement.

The second method that can be used to calculate the value of an ecosystem service is called the Expected Damage Function. This method estimates how a change in the ecosystem could increase the potential for damage created by a natural disaster such as a storm or flooding. In other words, how much could restoration or protection of these ecosystems decrease or offset the cost of damages caused by natural disasters.

Action

Although the number has dropped 31,000 acres, we are still losing 50,000 acres of wetlands each year. Unfortunately, I was unable to find the current number of wetland acres in the United States. President George H. W. Bush supported a “no net loss” federal policy goal for wetland habitats. The goal refers to wetland losses and gains with an overall net gain over time. Though presidents have continued to support this, and we have moved closer to this goal, we are yet to achieve it. Wetland restoration is key to maintaining a critical wildlife habitat, to meet watershed goals and contribute to economic well-being. Many states have invested in programs with the goal of long-term wetland regulation, preservation and restoration efforts. There are severe consequences of wetland habitat destruction like flooding, species extinction and a decrease in water quality. However, if we can advocate for protecting the valuable wetlands we still have and work towards resorting wetlands where possible, we can avoid further consequences.

References

Clarkson, Beverley & Ausseil, Anne-Gaelle & Gerbeaux, Philippe. (2014). Wetland ecosystem services.

Conservation Fund, Houston-Galveston, Green Infrastructure and Ecosystem Services Assessment, 2013, last visited August 23, 2020 here: http://www.conservationfund.org/images/projects/files/Houston_Galveston_Report.pdf

Woodward, Richard T. and Yong-Suhk Wui. 2000. “The Economic Value of Wetland Services: a Meta-analysis”.Ecological Economics 37: 257-270.