In the inky blackness before dawn, I could only make out the faint outline of a wooden railing, slats beneath my feet. Here and there, reflected starlight on the water created a shimmering iridescence amidst the shadows. The quiet metronome of my feet against the ground was suddenly drowned out by a cacophony of tuneless honking. In front of me, my dog stopped, ears perked. How many of them were there – only dozens, or were there hundreds? How many geese floated on the water, cloaked by darkness, and what other animals hid in the wetland, still silent and undetected? What ecological wonders would I see if someone turned on the light?
Minnesota is the land of ten thousand lakes, but it is also the land of ten million wetlands. These oft misunderstood features are sometimes wet and sometimes dry, vitally important to people and wildlife, and yet virtually impossible to explore by foot or by boat.
Officially, there are eight types of wetlands in Minnesota, though people use many names to describe each type: bogs, shallow and deep marshes, shallow open water, shrub and wooded swamps, seasonal basins, wet meadows and calcareous fens. Minnesota has lost almost half of its wetland acreage since European settlement, but there are still roughly 10.62 million acres of wetlands remaining. If you aggregate together all of the wetlands across the state, their overall health is good. Approximately 75% of the wetlands are in northern and northeastern Minnesota and 84% of these have clean water and high-quality, natural vegetation. If you look specifically at wetlands in southern and western Minnesota and the Twin Cities metro, however, the picture is rather different.
In the metro area, the vast majority of our wetlands – 82% – have been taken over by invasive species like purple loosestrife and reed canary grass. In southern and western Minnesota, wetlands have vanished all together and only 5% of the original wetlands still exist. Most of the ones that remain are highly degraded, taken over by invasive plants, sediment and excess nutrients.
Beleaguered though they may be, wetlands provide critical services to humans and wildlife. To begin, wetlands are highly interconnected with lakes, streams, and groundwater resources. Wetlands along the edges of rivers, streams and lakes provide flood protection and reduce shoreline erosion. Some wetlands collect surface water from rain and melting snow and allow it to soak into the ground, replenishing groundwater supplies. Others bring cool, clean groundwater to the surface of the land, creating unique habitats for plants and animals. Wetlands often act as filters, pulling sediment, nutrients, and pollutants out of runoff water before it flows into lakes and streams. However, like human kidneys, they can become overwhelmed in the process. When wetlands stop functioning properly, they no longer provide protection for lakes and streams and sometimes even become a source of pollution to these other water bodies.
Wetlands are incredibly rich habitats. Approximately 43% of threatened and endangered plant and animal species in the U.S. live in or depend on wetlands. Many species of fish spawn in wetlands adjacent to lakes and ducks, geese and other waterfowl descend upon Minnesota wetlands in tens of thousands during their spring and fall migrations. Other animals like frogs and toads lay their eggs in seasonal wetlands during the spring.
The federal “No Net Loss” policy aims to maintain the current total acreage of wetlands in the United States. Minnesota’s Wetland Conservation Act requires anyone proposing to drain, fill, or excavate wetlands to first, try to avoid disturbing the wetlands; second, try to minimize any impacts to the wetlands; or third, replace any lost wetlands by creating new wetlands in another location. The act is administered by the MN Board of Water and Soil Resources, enforced by the MN Department of Natural Resources, and implemented by local government entities across the state. Local and state conservationists also work with landowners to convert minimally productive farmland back to wetlands when practical.
The MN Pollution Control Agency notes that there was a slight gain in wetland acreage in Minnesota between 2006 and 2011, but most of the gains came from projects that converted natural wetlands to cultivated ones or built pond-like wetlands to replace those lost to development. Nature is a difficult artists to mimic, and these types of human-built wetlands typically lack the right vegetation to provide good wildlife habitat.
Locally, a number of unique and high-quality wetlands still exist, even in the midst of burgeoning development:
- Woodbury: The Tamarack Nature Preserve contains many rare plant species and can be enjoyed from a number of boardwalks crisscrossing the wetland.
- Stillwater: The wetlands flanking Lake McKusick contain many rare plant species and can be enjoyed from the walking trails or boardwalk surrounding them.
- Maplewood: Maplewood Nature Center also has a floating boardwalk to help visitors explore the marsh on site.
- May Twp: The south end of Big Marine Lake can be partially accessed by canoe, while trails lead past other wetlands in Big Marine Park Reserve. At Warner Nature Center, the quaking bog contains a miniature fantasy world, complete with meat-eating plants.
- Marine on St. Croix: The low-lying seeps and springs at William O’Brien State Park nourish some of the earliest spring wildflowers, while pothole wetlands on the ridge provide a welcome rest for traveling birds.
- Oakdale: Explore trails through woods and wetlands at the Oakdale Discovery Center.
- Lake Elmo: Trails at Lake Elmo Park Reserve and Sunfish Lake Park also wind past countless wetlands and ponds.
- North St. Paul: Southwood Nature Preserve is a little-known gem with a surprisingly high-quality array of aquatic plants and animals.
The Washington Conservation District is the clearinghouse in Washington County, MN for information about wetlands. Visit www.mnwcd.org for more information about permits for projects impacting wetlands, assistance identifying wetland boundaries, and projects to improve local wetlands.