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Prairie. Merely thinking the word conjured images of covered wagons and bison and homesteads, and… well, and not much else. When I racked my mind for further knowledge of prairies, all that surfaced was the book title Little House on the Prairie, and so little houses also occupied the prairies of my imagination. Otherwise, all I knew of prairies were the glimpses I’d seen from afar, which mostly looked to me like large patches of yellowing grass.

Despite these antiquated associations and the gross inaccuracy of describing an entire ecosystem as a “large patch of yellowing grass,” I had heard at least one true thing about prairies: they are changing. Like glaciers, sea levels, growing seasons for crops, and so many other things, prairies are being affected by global climate change. With warming temperatures, the ranges of many prairie plant and animal species are shifting northward with the colder temperatures they are adapted to live in. Thus, as average temperatures continue to rise, what prairies- and their residents- look like may become quite different, and soon.

I decided that I needed to learn more about this mysterious and changing ecosystem. This quest took me to Tucker Prairie.

Tucker Prairie, which lies about 20 miles east of Columbia, is one of the last remnants of what was once an enormous prairie that covered much of Missouri. This patch of land is different from the grassland and farmland currently surrounding it because it is has never been tilled by farmers or their machinery. As a result, it contains a tough layer of clay in its soil that prevents water from draining away as quickly as on other, tilled land. This extra water nourishes a unique ecosystem that supports hundreds of plant and animal species.

Columbia

I-70

Tucker Prairie

After pulling off the interstate and rumbling down a few gravelly back roads, a barbed wire fence and a weatherworn sign reading “Tucker Prairie and Clair L. Kucera Research Station,” greets visitors to the prairie. Beyond it stands a green aluminum shed, dusty glass in its splintered window frames.

Once one takes the first few steps beyond the shed, it becomes abundantly clear why the prairie is unlike any other field of grass in Mid-Missouri: it positively hums with life, both literally and figuratively. Though you will not see any covered wagons, bison, or homesteads at Tucker (and no, there is a not a little house on the prairie—not this prairie, anyway), what you will see is an amazing variety of organisms. A dense thicket of grasses, flowers, and woody plants soars up high in all directions, with trails leading into its tangled midst. Thousands—no, millions— of insects roar from the tangled groundcover and buzz above and around it with noisy energy. This insect symphony is not without its ballet; above it, birds twirl about in what seems an elaborately choreographed dance, moving so quickly that you feel you might sustain a minor case of whiplash just trying to keep track of them all.

One of the species that sometimes joins the bird ballet at Tucker is Ammodramus henslowii, or Henslow’s sparrow. Named after John Stevens Henslow, a nineteenth-century botanist, minister, and teacher (of Charles Darwin, no less), Henslow’s sparrow is a grassland bird known for its reclusive, secretive nature. Some important facts about the sparrow are as follows:

©Chelsea Myers

Adult description: small songbird; mostly brownish, with sparsely-streaked breast; large head; short tail

Size: 4.3-5.1 inches in length, 7.9-inch wingspan

Habitat: grassland

Food: insects

Nesting: ground

Behavior: ground forager

Call: a very simple, thin, two-syllable "tsi-lick"

(listen to Henslow's Sparrow's call here)

Conservation status: near threatened

Information from: AllAboutBirds.com

To summarize, a normal day for a Henslow’s sparrow might consist of hunting for insects and feeding any chicks in its nest amongst the ground cover; males might occasionally pop up onto the tall grasses to sing and defend the territory they have established within the prairie, and, curiously, many Henslow's sparrows choose to run away through the grasses when a threat presents itself, rather than fly.

Henslow's sparrow makes its nest amongst tall grasses

Tucker Prairie is not Henslow’s permanent home, but rather a temporary one that Henslow’s might occupy during its breeding season in the summer. Other potential nesting sites extend east to the Great Lakes and all the way to Upstate New York. During the winter, Henslow’s migrates south towards the Gulf Coast and Southeast (see map below). As global temperatures rise, Henslow’s range is gradually shifting north; eventually, it may shift out of Tucker Prairie altogether.

Besides being in danger of having to leave its seasonal home at Tucker Prairie, Henslow's is in danger as an entire species. Its conservation status of "Near threatened" is due to habitat loss. Like many other kinds of ecosystems, prairies are being converted to farmland and housing developments, but they are also shrinking due to “woody encroachment.” Woody encroachment refers to increased growth of woody shrubs and trees, and can be caused by different land management practices and rising atmospheric concentrations of carbon dioxide, among other things. On the conservation status scale created by the International Union for the Conservation of Nature and Natural Resources, this designation falls squarely between the designations of "Least concern," and "Vulnerable.” In other words, Henslow's sparrow is not doing great, but it is two whole rankings removed from "Endangered," yet another from "Critically endangered," sufficiently far from "Extinct in the wild," and not even close to the bleak finality of the very end of the spectrum: "Extinct."

But, what will happen if Henslow’s actually leaves Tucker Prairie? Why does it matter if one species of bird (amongst over 30 at Tucker) and one so elusive that even experienced birdwatchers have trouble spotting it, is no longer there? What if it does go extinct, which it currently seems far from doing?

credit: National Audubon Society

credit: International Union for the Conservation of Nature and Natural Resources

This map from the National Audubon Society (left) illustrates the Henslow's sparrow's winter range (blue) and breeding range (red). Both ranges may shift due to changing average temperatures.

The International Union for the Conservation of Nature and Natural Resources' conservation status classifications (above) range from "Extinct" to "Least concern." Henslow's sparrow is ranked as "Near threatened."

Nobody knows exactly what will happen if Henslow’s sparrow is removed from the ecosystem at Tucker Prairie, and just like we don’t know what will happen at Tucker, we don’t know what will happen to Henslow’s as a species, or what will happen to prairie ecosystems across North America. But, we do know that everything is connected in these ecosystems. The presence—or lack thereof—of Henslow’s sparrow affects other birds, plants, insects, small mammals and even the soil. The culmination of these effects could be minimal, or it could be very large. Let’s take a moment to explore both possibilities.

If Henslow's Sparrow leaves Tucker Prairie, one possible result is that other bird species sharing a similar ecological niche to Henslow's may increase in number. The Grasshopper sparrow is one such species. The Grasshopper sparrow, like Henslow's, lives in prairie grasses, but it is more resistant to changes in this habitat such as woody encroachment. As woody encroachment converts more and more of the prairie to shrubland, different species such as Bell's vireo and the Eastern Kingbird will in turn dominate as the Grasshopper is pushed out.

In another possible future, the changes resulting from Henslow’s Sparrow leaving Tucker Prairie would be much more drastic; in other ecosystems, the removal of one species has changed not only affected other similar species, but the entire landscape.

Take, for example, the reintroduction of wolves in Yellowstone National Park: when wolves were reintroduced to the park in 1995 after a 70-year absence, their presence affected not only other species of animals, but also the vegetation and physical geography of the park. Watch this video from Sustainable Man to find out how:

Tucker Prairie is home to many plants and animals, such as (from top) Ashy Sunflower, various species of butterfly, and vervain.

As the case of the Yellowstone wolves illustrates, the presence of a single species can affect every part of an ecosystem. Though Henslow's sparrow may not be a keystone species, as the wolves are, no one can be certain how small- or large-scale an effect their removal from the prairie ecosystem would have. The question, then, is not only what will happen to the Henslow's sparrow's as human development and climate change continue to affect Tucker Prairie, but also what will happen to Tucker Prairie if Henslow's sparrow is gone.

Tucker Prairie, August 2015

What do you think?

TUCKER PRAIRIE

AND HENSLOW'S SPARROW

Columbia

I-70

Tucker Prairie