Tom's Blog

Friday, August 6, 2010

North American Prairie Conference Iowa

This week I attended the 22nd North American Prairie Conference at the University of Northern Iowa, Cedar Falls. These prairie conferences have been held every two years since 1968, and this one was hosted by the Tallgrass Prairie Center at UNI. Over 500 people attended, mostly from the Midwest. In addition to three days of papers and posters, one day was reserved for field trips.

The field trips are always a highlight of these conferences, because the host organization is always interested in showing off their best prairie and savanna sites. (When the NAPC met in Madison in 2004, Kathie and I conducted one of the trips: to Pleasant Valley Conservancy, Black Earth Rettenmund Prairie, and Swamplovers, Inc.)

Over a dozen field trips were run. On the one I attended we visited several small high-quality prairie remnants. Plentiful rainfall had also occurred in Iowa, so the prairies were lush and colorful.

The first prairie we visited was a 1.5 acre prairie in a small, very old, cemetery. This cemetery had not been used for burials since the 19th century, and there were very few gravestones. A nearby resident with a passion for prairies maintains this site, cutting brush, pulling weeds, and organizing prescribed burns. The plant diversity was fairly high. Among the species there was lots of prairie dropseed (Sporobolus heterolepis) and compass plant (Silphium laciniatum). The site reminded me quite a bit of Aldo Leopold's Faville Grove Sanctuary in Jefferson County, WI, although prairie dock was absent here. (It turns out that prairie dock's western extent is near the Mississippi River.)

The second prairie we visited was a "railroad" prairie, existing along the right-of-way of the Burlington Northern Railroad. Railroad prairies were very common in the prairie areas in the 19th century, because the land adjacent to the railroad was not plowed. Also, the steam engines, mostly wood burners, spewed out sparks and burning ashes which set the prairies on fire. In the 19th century, virtually every railroad right-of-way burned almost every year.

The prairie we visited has an interesting history, since a resident of the nearby town who cherishes this site leases the prairie strip from the railroad for $100 a year, and the Tallgrass Prairie Center conducts frequent burns. Because of the topography, there is a gradient at this site from fairly wet at one end (lots of Liatris pychnostachya) to dry at the other end (lots of Eryngium yuccifolium and Liatris aspera).

Fortunately, the railroad only sprays a narrow zone near the tracks, so that none of this prairie is herbicided.

One of the pleasures of these prairie tours is that the participants have a wide variety of expertizes. On our trip there were quite a few Iowa residents who knew the local flora well, and there were those from more distant areas who could add their own perspectives. The brief discussions in the field often provided great insights into prairie ecology.

The third remnant we visited was a strip of prairie that was sandwiched between a railroad on one side and a highway on the other. The road had once been a major U.S. highway, but was replaced by a throughway nearby, making this road relatively peaceful. The highway commission has granted permission for the Tallgrass Prairie Center to conduct prescribed burns, and this site was relatively pristine. The interest here was that bedrock was very close to the surface, so that they site was very dry. Again, lots of L. aspera. Because this part of Iowa was extensively glaciated, sites with exposed bedrock are not common. (Iowa has only a small part of the Driftless Area, in the northeastern part of the state, near the Mississippi River.)

The conference itself was extremely well organized by the staff of the Tallgrass Prairie Center. I had a chance to visit the Center's facilities and will report on them on another post.


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