Tracing Native Prairie

Big bluestem, aka turkey foot, is a warm season grass that’s pretty easy to identify in a native prairie. That’s because it ripens to a distinctive purple-red color this time of year. And, the top has a shape like a bird’s foot that’s easily recognized. So, it’s an indicator plant that helps to track and trace native prairie. Big bluestem is also a common component of commercial prairie seed mixes, probably for similar reasons.

We’re grateful to have at least four separate patches of big bluestem on the Farm: 1) roadside, 2) house yard, 3) prairie parcel, and 4) grazing paddocks. The four areas are different sizes, have had different histories, have different levels of biodiversity, and probably have completely different types of disturbances influencing their growth. This post has a long shot of the general setting and a close up photo of big bluestem from each of the four areas.

The first area is along the edge of the gravel road that is the state line between Minnesota and Iowa. It’s small and sparse, but it’s a unique natural planting of native grass. Ten or fifteen years ago Kanaranzi Creek routinely flooded over its channel banks in the spring. After one of these annual spring floods the water covering the road at this location apparently carried grass seed because then we started seeing big bluestem along the roadside. The associated plants in the ditch are mainly “weeds” but do include milkweed. So this is a relatively small, thin patch that was seeded by a natural process and has a relatively low diversity of associated plants. It is, however, subjected to a fairly regular disturbance when a grader maintains the gravel road.

The second area is in our house yard and was planted with a commercial seed mix ten years ago. It was a fairly simple mix that had little bluestem and Indian grass in addition to big bluestem, but it is mainly the distinctive big bluestem that has survived. Although the patch is reasonably robust and dense, it seems to be contracting every year under pressure from the surrounding smooth brome. The area is somewhat larger than the roadside patch and the initial low grass diversity has decreased even more. Fortunately there are a number of other associated plant species as you can see in the photos. We’ve burned it two or three times, so there has been some disturbance to cut back on the thatch and reinvigorate growth, but it’s not a particularly healthy native prairie.

The third area is a patch of native prairie that has probably been located on this unplowed, west-facing hill slope for centuries. The post from July 15, 2020 (https://lonetreefarm.blog/2020/07/15/weeds-and-feed-learning-from-a-prairie-hill/) describes this part of the pasture in more detail. It’s a one-acre parcel that has been excluded from grazing for about ten years, but this year it was integrated back into the paddock system. There’s a high (40 species) diversity of mostly native plants that have apparently grown from the soil seed bank, which has been “storing” native seeds for generations. The big bluestem seems somewhat sparse because grazing has resumed, but the overall diversity is very high compared with the other three areas. We probably should have done periodic burning, but now the grazing will provide some annual disturbance.

The fourth area is about fifteen acres currently subdivided into three paddocks. In 2015, the parcel was converted from row crop cultivation and planted with a commercial seed mix of five warm season grasses (big bluestem, wheat grass, side oats grama, switch grass and Indian grass). For the first several years there was no grazing, but establishing this as a warm season paddock complex has not been simple. Initially, Chinese elm seedlings had to be sprayed; then two record-setting wet years brought out seeps and springs that changed the vegetation; and finally the competition from smooth brome has been incessant. Now, one of the three warm season paddocks is in pretty good shape with vigorous big bluestem, but the other two will need some work and possible re-seeding. 

There are at least half a dozen other patches of prairie marked with diagnostic big bluestem in our two hundred acres of pasture. Like the four areas described in this post, the other parcels contract and expand from year to year with varying weather conditions and disturbances by grazing. However, what’s unique about all of these additional prairie remnants is that they, like the hillside exclusion, probably have all developed from the soil seed bank where native species have been dormant and preserved for many years. This may represent an important resource that’s an alternative to expensive commercial seed mixes and provide a gene pool of local species. But, how do we go about “waking up” these native prairie seeds and get them going again? That’s not a rhetorical question. We would really appreciate some practical suggestions!

About Lone Tree Farm on Kanaranzi Creek

Recovering academic, earth scientist in phased retirement, farm manager by default, son, husband, father, grandfather.
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2 Responses to Tracing Native Prairie

  1. margshurr says:

    It’s interesting how long they can remain dormant.

    Like

  2. Pingback: Battling Brome | Lone Tree Farm on Kanaranzi Creek

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