Monday, November 25, 2013

A Famous Invader

It sounds like a dark riddle: what famous invader disrupts developing frog embryos, prevents meadow rues from germinating, and is allied with invasive earthworms?  If you think something so destructive is found only in sci-fi movies, then you’d be surprised to learn it’s an enemy that volunteers have been battling at Coldwater: buckthorn.

Common buckthorn leaves
All of the green shrubs  shown above are buckthorn.
Buckthorn is fierce competition for many plants at Coldwater because it is so good at many of the very normal things plants do. Its dense foliage soaks up so much sun that plants underneath it don’t get enough sunlight to survive. Its berries are irresistible to birds, and like kids eating candy, they gobble them up and distribute evidence of their foraging widely, thus spreading the seeds. Buckthorn bushes also display a zombie-like determination to live after being cut down. If you remove the trunk and fail to apply herbicide before leaving the plant to die, the stump will send up many new shoots and continue to thrive.

Western Chorus Frog
Western Chorus Frog eggs are affected by buckthorn.
Buckthorn has many effects on nearby living organisms that are unusual for plants. For instance, buckthorn excretes high levels of a chemical called emodin during leaf out, coinciding with activity from early-breeding amphibians. The timing of this is particularly devastating to frogs because this chemical, which is released from all parts of the plant, has shown toxic effects on amphibian embryos, including disrupting their development and preventing them from hatching.

Meadow Rue in bloom
Buckthorn leaf litter also has a dramatic effect on the growth of beautiful forest plants called meadow rues because it poisons the soil. When seeds from a species of meadow rue were placed in soils under buckthorn’s leaf litter, the percentage of seeds that germinated was reduced by more than 10%. The meadow rue seeds that could grow in these conditions germinated nearly a week later than seeds growing under maple leaves. This makes it harder for the meadow rue to survive because other plants get about a week’s head start, giving them the advantage as they compete for water, nutrients, and sun, making it harder for meadow rues to survive.

Meadow Rue leaves are delicate and beautiful
In addition to inhibiting the development of native frogs and flowering plants, buckthorn hurts the forest by facilitating the growth of invasive earth worm populations. No earthworms are native to Minnesota, but they are in our soils from when people transplanted European plants in European soils, complete with European earthworms, and from fisherman releasing unused worms intended as bait into the soils. Minnesota’s plants evolved to conditions in which leaf litter decomposes slowly. Slowly decaying litter is the growing medium of choice for many understory plants and flowers, and the ideal home for many microbes, insects and invertebrates that make up the base of the woodland food chain. Buckthorn leaves are preferred by earthworm populations and they provide such a good source of food for them that their populations are much higher in the soils surrounding buckthorn plants. Where there are more earthworms, there is less leaf litter that is needed by many plants and animals to grow, so their populations decline.

At Coldwater Spring, the National Park Service and Mississippi River Fund, together with help from thousands of volunteers, have cleared old growth buckthorn from 29 acres over the past 3 years. Though we will continue to deal with sprouting seedlings for years to come, we hope that these efforts will improve the oak savanna and woodland habitats at this important historical and cultural place. Though we will probably never completely rid the world of buckthorn, restoring natural spaces for native plants to survive will help create places for birds, frogs, and people to thrive.

Volunteers have removed buckthorn from many areas in our National Park

Written as a joint effort between Maria DeLaundreau and Anna Waugh.

Tuesday, November 19, 2013

Coldwater Spring's cool wetland

It looks like just a shallow pond, but there’s a story behind and beneath Coldwater Spring’s north wetland.

Often overlooked, overshadowed by the iconic springhouse and burbling creek, the north wetland sits modestly by the park’s northern edge, tucked between the oak grove and prairie, guarded by a towering cottonwood.

Where the wetland sits now, once a building stood. Bureau of Mines Building 9 was the agency’s library, a resource of papers and information. Former BOM staffers say it was a library with soggy basement. So why did the Bureau build there? Well, they didn’t. The agency didn’t have money to build, so instead, they hauled an building from the Iron Range and set it downclose to the sprawling headquarters building where most Bureau staffers worked.

When the National Park Service began restoring the park, step one was demolishing of all twelve Bureau of Mines buildings, including the soggy library. Construction crews began tearing down the library in late December 2011, but the basement was still sodden. Crews began pumping out the water, but within days, water had seeped back.

The Park Service realized the library was sitting atop a natural wetland. When they tested the water, the wetland’s northwest corner seemed to be a rare kind of wetland -- a calcareous fen. Minnesota is one of just ten states with calcareous fens, which require very particular conditions — the right mix of non-acidic soil, lots of cold groundwater with calcium and magnesium but not much oxygen. Neither Hennepin nor Ramsey County had any such fens. These finicky fens sometimes feature uncommon plants like brook lobelia, shrubby cinquefoil and fringed gentian.

The Park Service wants to nurture the potential fen. To avoid altering the wetland’s acidic balance, they didn’t remove the library’s foundation. They set limestone steps in the northwest corner by the fen and across the wetland by the massive cottonwood.  The steps make it easy for visitors to see and touch the wetland’s waters. School kids can do simple experiments to test the water.

There’s no guarantee that the north wetland will support a calcareous fen, but it’s possible. What’s certain is that where an old building once stood is now home to a wetland, fringed with grasses and native plants. A wetland where whitetail deer browse and drink, where woodchucks scurry into a nearby hole, where an eagle sometimes perches on the cottonwood’s tall branches. It’s one of eight wetlands at Coldwater, all made by natural groundwater seeps.

It looks like just a shallow pond, but there’s a story behind and beneath Coldwater Spring’s north wetland. 

Wednesday, November 13, 2013

Giving Kids a Ticket to Ride

“It was amazing to be on the Mississippi River in a boat and see real animals close by. 
I want to come back!”
“It was awesome! It was the first time I saw a real waterfall!”
“I learned that taking care of nature is like taking care of us.”

- Big River Journey Students 2013

As one of the country’s few national parks in an urban area, the Mississippi National River and Recreation Area has a rare opportunity: it is poised to provide outdoor experiences for thousands of city kids who might otherwise never get to visit a “traditional” national park.

Our park’s unique river programs give urban youth a chance to create a personal connection with the outdoors and the Mississippi River through educational experiences on the river itself, right in the city, often just steps from home.

But, for the majority of young people in our community, access to these programs requires overcoming significant barriers. The outdoors may seem too far away, too unfamiliar, or too expensive to access. Most of these kids have never been on the river—or even in a boat. The reasons for non-participation are complex, but we realized there is one thing we can provide to at least get them there: a Ticket to Ride.

By providing funds for kids’ program registration, boat tickets, or simply bus fare to get to the river, the Mississippi River Fund’s Ticket to Ride scholarship fund is enabling thousands of young people to take part in park programs that help them begin a lifelong relationship with the river and the outdoors. Programs like Big River Journey, Urban Wilderness Canoe Adventures, and Take Me to the River teach kids about the incredible history, value, and importance of the Mississippi River; they teach outdoor skills like paddling, bird watching, plant and animal identification, fishing, and the critical role they play in caring for nature.

We have a national park in our back yard. As the charitable partner of the National Park Service, it is part of our mission to strengthen the connection between people and the Mississippi River. Let’s begin that connection with the young people in our community today—the same people who will care for our national park tomorrow.

Our goal is to provide 3,000 kids with the means to take part in national park programs on the river in 2014. Will you join us?

To learn more about the Ticket to Ride scholarship fund, visit

Monday, November 4, 2013

Thoreau’s first and last trip to Minnesota

What two Minnesota marvels wowed Henry David Thoreau?
Henry David Thoreau put Walden Pond on the map, and made a name for himself by writing about life and nature in Concord, Massachusetts where he spend most of his life.
But in 1861, a year before he died, Thoreau ventured west to Minnesota, traveling roughly thirty-five hundred miles. It was the longest, and last, trip of his life. So what drew him here? Oddly enough, Thoreau came for our climate. He wrote a friend that, "it will be most expedient for me to try the air of Minnesota, say somewhere about St. Paul's." At age 43, Thoreau was already suffering from the lung problems that would cause his death, so he heeded his doctor's call for travel.

On May 11, 1861, Thoreau and a companion, Horace Mann, Jr., a botanist and son of the famed educator, took a train headed for Chicago. After a leisurely trip west with scenic stops, the men boarded a steamboat at Dunleith, known now as East Dubuque, Illinois, and began their expedition up the Mississippi River.
To Thoreau, the Mississippi was "the grand feature hereabouts." So what else about Minnesota moved the great writer? Well, not St. Paul. Thoreau judged Prairie du Chien as "the smartest town on the river," while St. Paul's buildings were constructed of "poor stuff." He stayed in St. Paul just long enough to have breakfast and then moved on to Minneapolis and St. Anthony where he spent two weeks happily roaming, often with the state geologist, Dr. Charles L. Anderson.
It was in Minneapolis where Thoreau saw up close what had long eluded him. Henry David Thoreau wrote about wild crab apples the way birders speak of ivory billed woodpeckers. He had contemplated traveling to Pennsylvania just to find the "half-fabulous" tree which he had only seen in books. In Wild Fruits, his posthumously published final book, Thoreau writes that he first spied his elusive treasure as the train chugged through Michigan, spotting "a tree with handsome rose-colored flowers. At first I thought it was some variety of thorn, but it was not long before the truth flashed on me -- that this was my long-sought crab apple. It was the prevailing flowering shrub or tree to be seen from the cars at that season of the year -- about the middle of May. But the cars never stopped before one, and so I was launched on the bosom of the Mississippi without having touched one, experiencing the fate of Tantalus."
When Thoreau reached St. Anthony Falls, he was told he was too far north to see his tantalizing crab apple. But just a few miles west of the falls, Thoreau finds, touches, and smells the tree of his dreams. He writes that he "secured a lingering corymb of flowers for my herbarium." (Note: corymb is my word of the day, which the dictionary describes as a botanical term for a flat-topped cluster of flowers in which the outermost flowers are first to open.)
I imagine Thoreau stalking the wild crab apple, dressed in his 'best pants,' flannel shirt, and 'half-thick coat,' armed with spy glass, notebook, botanical manual and tape measure, not to mention the hat he jury-rigged with a slight shelf inside the crown to tuck plant specimens. He gently touches the faded corymb, his prizedcrab apple blossom, smiling as he envisions the delight he'll have back home in Concord every time he examines his herbarium, which now holds his flowering crab apple, found in Minnesota.
Thoreau had planned to stay three months in the Midwest, but cut his trip short, and was back home in Concord by July. Maybe he grew weary of travel. But maybe he'd seen enough. He found his wild crab apple.

In Thoreau’s rediscovered final manuscript, Wild Fruits, published in 2000, the naturalist devotes nineteen pages to wild apples, noting, "I know of no trees which have more difficulties to contend with and which more sturdily resist their foes. These are the ones who story we have to tell."
And this is the time to tell the story of apples. Thoreau notes that late October and early November are the season for wild apples. As I bite into a small, tart apple, picked at a Minnesota orchard, I savor Thoreau's ode to apples and their "wild flavors of the Muse, vivacious and inspiring."
As Thoreau wrote, "Every wild-apple shrub excites our expectation thus, somewhat as every wild child."
Wild Fruits, by Henry David Thoreau, edited and introduced by Bradley P. Dean, W.W. Norton & Co., 2000.
Thoreau in Minnesota,” by John T. Flanagan, a paper read at the
Minnesota Historical Society, on Jan. 21, 1935; online at