Home / Environment / Restoring wetlands needs science, art, patience

Restoring wetlands needs science, art, patience

By Dave Orrick
St. Paul Pioneer Press

Hydrologist Eric Mohring and soil specialist Megan Lennon of the Minnesota Board of Water and Soil Resources examine dirt from an auger June 18 in a restored wetland in the Janet Johnson Memorial Wildlife Management Area in North Branch, Minn. (AP photos by Dave Orrick/St. Paul Pioneer Press)

NORTH BRANCH, Minn. (AP) — Megan Lennon and Eric Mohring are debating which shade of “muck” they’re staring at.

“I’m getting 3.1: ‘mucky modified,'” Lennon said.

“Or is it 2.1: ‘mucky loam?’” Mohring asked.

Were they not rapidly becoming covered in dirt and swiping ticks off their pant legs by the half-dozen, you might think Lennon and Mohring were picking out wallpaper patterns for some hipster decor.

Each grabs and crumbles a handful of dirt, then moves it across a palette of colors, trying to agree on which is the best match.

This, in part, is how wetlands are restored. It’s both art and science, and takes years.

The typical narrative of a wetland restoration project goes like this: A government agency announces acquisition of land; years later, a ribbon-cutting ceremony is held, and hunters and birdwatchers enter with high hopes.

But between those two moments there is the restoration itself: Heavy machinery eviscerates the land, herbicides poison plants and trees, and cement might be poured into waterways — otherwise offensive practices on a natural landscape were it not for the ends justifying the means.

Holes are dug, ditches are rerouted and seeds are planted, many of which fail to sprout.

A land transforms from bean farm to construction site to something that, hopefully, looks as if humans never had touched it.

Wildlife returns and flourishes. And people such as Lennon and Mohring try to agree on the color of muck.

On this day, Lennon, a soil specialist, and Mohring, a hydrologist, are part of a team of scientists and staff from the Minnesota Board of Water and Soil Resources verifying and quantifying the success of a years-long wetland restoration project in the Janet Johnson Memorial Wildlife Management Area, in Chisago County north of the Twin Cities.

This “delineation of wetland restoration,” as it’s called, is the grimy underbelly of the sexier side of wetland restoration: a landscape teeming with wildlife, especially waterfowl.

But wetland delineation also is the bedrock of the project — because you can’t necessarily just dig a hole in the ground, fill it with water and expect to have built a maternity ward and nursery for ducks, meadowlarks, pheasants, terns and the like, although that once was seen as sufficient.

Megan Lennon breaks apart a clump of dirt to reveal colors in a restored wetland in the Janet Johnson Memorial Wildlife Management Area in North Branch, Minn. Red hues in soil reveal clues about how bacteria oxidizes iron, which can help scientists determine what types of plants an area might be hospitable to.

“This was once a tamarack wetland, but for years it was a sod farm, and beans were planted,” said Dan Shaw, a vegetation specialist and landscape ecologist with the BWSR. “A lot of that original seed bank was lost.”

The waterfowl might not know it, but the key to a quality wetland is not merely the prevalence of water. The tripod on which a wetland sits consists of hydrology (or behavior of water movement), vegetation and soil chemistry. Seed one type of grass in a soil that isn’t compatible, and you’ll get a mud pit instead of a wildlife-harboring meadow’s edge.

The goal of this wetland restoration, which began in earnest in 2006, was to create a “wet meadow,” in the parlance of wetland definitions. It’s not a sea of water with lily pads and cattails.

“A wet meadow creates a whole different set of habitat,” Shaw explained. “But when we started this, there wasn’t a whole lot known about seeding a wet meadow. We’ve learned a lot from this site.”

Greg Larson, a gray-bearded BWSR soil scientist who has witnessed the evolution of habitat restoration since the 1970s, said the science still is evolving.

“You don’t always know what the hydrology will allow,” he said. “You don’t know if all the pieces will come back as you hoped, but today we know a lot more than we used to.”

To that end, the BWSR, a state agency that funnels federal and state grant wildlife money through an array of wildlife projects statewide, is preparing a wetland restoration guide.

It’s a technical manual dealing with iron oxidization, pH levels, seed success and other bits of knowledge that can make the difference between a place where a half-dozen mallards might land for lunch and a place where they’ll stay for the season and raise a brood.

Copyright 2021 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.

Leave a Reply

Your email address will not be published. Required fields are marked *