The Gravel Pit
About 50 years ago there was some gravel mined from a small pit in the corner of my prairie restoration field. I don’t think there was a seeding made afterwards, but it soon grew up to bromegrass, with a few willows and cottonwoods in the lowest area of the pit where there is a perched water table. I often use the pit to store my trailer and ATV and finally took a closer look at it last week when I was up gathering seed from the existing prairies. What I saw was a bit surprising.
While the majority of the vegetation that has reclaimed the disturbed area is bromegrass, there are about 20 native species which have found their way to the site from nearby pastures. Some of these are the typically weedy species which blow around and colonize bare spots everywhere, such as Missouri goldenrod (Solidago missouriensis) and heath aster (Symphyotrichum ericoides), but many aren’t. There is a sizeable colony of leadplant in a protected area under the edge of the excavated hill. There are many dotted gayfeathers (Liatris punctata) which have blown in and colonized some of the poorest soils. There are bits of big bluestem (Andropogon gerardii) and plains muhly (Muhlenbergia cuspidata) fighting the good fight against the brome on appropriate sites. I found a couple prairie onions (Allium stellatum) which have somehow made their way over from my pasture. I even gathered seed for an hour or two from the gravel pit that I am spreading on the prairie restoration.
What will the gravel pit look like in 50 or 100 years? Will we have continued progress of the natives spreading from the prairies nearby, and from the restoration which now surrounds the site? Or will the brome push everything back out, perhaps advantaged by our increasingly wet climate. Even without the gravel excavation this is a xeric site, so it would be reasonable to hope that the more drought hardy native plants should have an advantage. Does this provide any lessons for the restoration field?
I think that one lesson is patience. Life will find a way to reach a new home. All the richness of our prairies developed over about 10,000 years since the glaciers melted and the climate stabilized at something approaching recent conditions. I am sure some researchers have determined about when our plant diversity reached maximum levels through pollen analysis, but my uninformed speculation would be that most of the plant community development occurred in no more than 2000 years. My restoration will be evolving to some sort of stability over the rest of my life, but will continue for long afterwards. I will obviously not know the final outcome of my restoration seeding, because there is no such thing. Which leads to the next lesson.
I need to be humble about my abilities to “create” a prairie. It has been suggested by multiple authors that those of us seeding restorations shouldn’t focus on the unattainable goal of a perfect, or an authentic restoration, but rather on the ecosystem services we wish to provide. What the hell would an “authentic” prairie restoration look like, anyway? Nobody truly knows. My stated purpose at the beginning of this process was to enlarge and buffer existing Dakota skipper butterfly habitat. That can fit under the broader umbrella of pollinator support. Then there are all the other insects, birds and mammals which will use the area (I have already been kicking up sharptail grouse and various sparrows, probably eating the weed seeds which I have grown. Carbon storage, water quality improvement and providing good habitat for bird hunters all add to the benefits. One benefit I personally care about is to increase the local genotypes of the xeric prairie species I have been gathering the seed of and spreading over the 100 acres. It pleases me to have an opportunity to give them a new home on the restoration prairie. I don’t think it helpful to have an image in my head that the restoration should match, because I doubt that I have enough imagination to see any image other than a pale approximation of the nearby prairie in my pastures. Rather, I will hope to see what develops over the next couple years and manage for my enjoyment, and to achieve some of these goals.
And this leads to the third lesson, which is that I already should be planning for management on the restoration. The gravel pit has developed some species diversity and distribution without any management. Could we have done better with active management? I will probably find out in a few years, because the gravel pit will probably get burned with the restoration field in a few years. In eight years, when the CRP contract has ended it will likely become part of a grazing system with the adjoining restoration. In the meantime I will be doing some weed control, both mechanical and chemical, and perhaps some remedial seeding. But I need to remember the second lesson, humility, as well. Perhaps the changing climate means that brome and Kentucky bluegrass are integral parts of the restoration 100 years from now, or perhaps some invasive grass that has not even yet reached South Dakota. I am 64 years old with health issues. I may not even see the end of the CRP contract and management will then move to other family members or to someone who buys the land, something over which I will likely have no control. In the meantime I will humbly do my best to guide the management to accomplish some of the goals I mentioned and perhaps some other goals I haven’t yet discovered. Its going to be a lot of fun!