Comparison of Natural and Human-made Wetlands

Quick review

Common wetland features:

Wet at least part of the year

Water level is at or near the surface

Soils are often saturated with water

Home to specialized organisms that are

adapted to wet conditions

What are wetlands?

Wetlands are like transitional zones. They’re not

as wet as lakes, but they’re not “dry ground”

either. They’re somewhere in-between.

Image source: http://www.dem.ri.gov/programs/benviron/water/wetlands/whatis.htm

Wetlands are valuable

Wetlands support life!

High biodiversity

Critical habitat for many endangered species

Wetlands are valuable

Humans benefit of wetlands:

Water purification

Groundwater recharge

Protection from storms and floods

Prevention of erosion

Aesthetic values (scenery, wildlife viewing)

Wetland losses

About ½ of the wetlands originally in the

U.S. have been drained or filled

Agriculture

Roads and railways

Urbanization

Wetland losses

Since wetlands are flat, they were

historically thought to be better-suited for

farmlands

Wetlands were considered “wastelands”

Wetlands impeded transportation routes

Many people were afraid of wetlands!

Current opinions of wetlands

Now they are valued for the many benefits

they provide

Draining or filling is now illegal without

proper permits

Even with permits, new wetlands must

often be constructed to compensate

“Wetland mitigation”

Wetland mitigation

Process of creating new wetland

ecosystems

Two common options:

Construct new wetlands where wetlands

never existed before

Restore wetlands in an area where they used

to exist in the past

Wetland mitigation

Process is overseen by State and Federal

agencies, to ensure that permit

requirements are met U.S. Environmental Protection Agency (EPA)

Michigan Department of Environmental Quality

(MDEQ)

Wetland mitigation

Our research question: How do human-

made wetlands compare to natural ones?

Hydrology

Soils

Vegetation

What the research says

It’s hard to build wetlands!

Mother Nature appears to do a better job

than us

Challenges of creating/restoring wetlands: Re-creating natural hydrology (water characteristics)

of wetlands

Keeping exotic plant species away

Developing rich, organic soils

Problem: Improper hydrology

Too wet! This is basically a pond, not a wetland.

Problem: Improper hydrology

Too dry! This is basically a grassland, not a wetland.

Problem: Exotic plant species

Phragmites australis

Melilotus alba

Problem: Organic-poor soils

Wetland mitigation

Despite challenges, many “good” wetlands

have been created or restored

Even marginal-quality wetlands can offer

benefits to wildlife and people

Over time, human-made wetlands can

begin to look more like natural wetlands

Our field exercise

Examine human-made wetlands in our

area and compare to the natural ones

we’ve studied already

How are they similar? How are they different?

Hydrology, vegetation, soils

Our research question: How do human-made

wetlands compare to natural ones?

Any questions?