Tuesday, July 16, 2013

Accrual through Fire

In January, 2012, following a 1,082 acre prescribed fire in November 2011, we set out across the blackened landscape to find rebar, stakes in the ground indicating research plots. Much research was conducted in this area long before GPS units, and, because the area has been treated with prescribed fire for 30 years (and regular wildfires upon settlement), researchers have descended on the site and marked their point count survey circles, their vegetation plots, their small mammal tracking locations, and so forth, but never coughed up the locations so we could relocate them in the future. So, we went out that week in January and flagged rebar. Tons and tons of rebar, some of the stakes were spraypainted blue, some white, some chest high, most of them pounded into the ground to leave only a few inches above ground. Together, with our combined knowledge of research taking place, my colleague and I were able to determine the owner of many of the plots, but after our combined 20 year knowledge of research plots, and after the 200th stake of rebar was discovered, we just flagged them because they were there.

I'm sort of a data hoarder. I love combing over historical vegetation data, relocating the plots, and then sampling in the mid-2000s to see how these areas have changed vegetatively. In 1995, when my supervisor was in my position, he initiated a vegetation sampling exercise in the 1,082 ac. burn unit, at that time following three rx fire events, to determine if successive fires and soil buildup through the development of thatch would allow for species richness to increase. He spent many days and nights at his plots in these dry chert woods, working through the legumes and Panicum keys. He collected great data in 1995 and again in 1998, but he hasn't been back to his plots. So we set out to find them with his hand drawn topo map, his triangulations ("320 degrees, 41 steps from plot 16..." etc. His long legged one step is two of my steps, I figured out quickly.) Thankfully for us and our flagging exercise, his rebar, unlike the other thousands of pieces of rebar in the ground there, possess a little curl at the top so we could find all four corners of each plot.

In preparation for this fun resampling exercise, I combed through his data sheets, made certain I was familiar with all of the plants he recorded. I spent a lot of time in the herbarium, made crude little drawings of the multiple lespedezas and desmodiums, notes on sterile sedges (knowing I probably wouldn't reach these plots until after my glade plots so the perigynia are blasted out), really studied the woodland Panicums, and so forth. Botany is hard work, which is why I admire the great botanist we have in Missouri today.

We set out today for the first of my woodland sampling to visit his 16 large plots and discovered that another researcher decided to use the area for their own research and in so doing, they removed our flagging tape because it was the same color as theirs. After relocating the plots for the second time (a two hour exercise), and this time through rich, thick woodland vegetation and not blackened earth, I finally threw down my quadrat. In one small quadrat, I had six species of legumes (three desmodiums and three lespedezas, and only half of them the commonly encountered ones here), four species of Panicums, and a suite of plants I could easily identify. I flipped through my homemade guide with all my notes, I referred to my boss' data, went to Steyermark, and spent 7 hours on 36 woodland quadrats. I have about 84 more to go.

It was a hot day rich with seed ticks. I thought that it would be prudent to finish my (open sun) glade plots in June to repair to the woods in July. The woods here are so open that after thirty years of rx fire, closed canopy shade and cool conditions don't really exist in the white oak-black oak-post oak woods on this ridgetop. What did exist, however, was several new plants in my boss' plots.

In 2003, I joined my colleagues in an effort to characterize the natural communities here by conducting general surveys of the flora throughout the area. We carved up the dominant dry chert woods into little units based on slope, topography, aspect, walked through the area to make plant lists and then assigned general cover values to each plant--this was not true science, of course, and not exhaustive. But from the exercise, we generated plant lists for small areas including the one my boss' plots are in. My colleague brought those plant lists along, too, for reference. In the 36 quadrats we completed today, we found a number of species that were not listed on either list, including the very commonly encountered Scleria pauciflora. Maybe the wet year is favoring Scleria? Or maybe it's just taken its time to come back, that it required that formation of thatch buildup that supports soil damaged by grazing. Maybe the drought-wet cycle triggered it to come up? Also in the woodland plots today and absent from the 1995, 1998 and 2003 lists was Viola pedata, normally encountered on glades in the Western Ozarks. I recognize that in the Eastern Ozarks, this is a woodland plant. Perhaps it is in my neck of the woods, too, but in my years of botanizing high quality Western Ozark landscapes, I've never seen it in the woods. The openness of the dry, rocky chert woodlands, formed through the years from a long fire history, may now be allowing some of these deep rooted perennial glade plants to express in the woods. We also found three new desmodiums, Festuca paradoxa, and several new grasses. I still have many more plots to finish.

Cover values are also markedly different from the 1995 plots and today. Warm season grasses in the 1990s accounted for very low cover percentages, with bare soil garnering 30-40% of some of the quadrats. Today, thick stands of grasses provided the matrix for legumes and other forbs that dominated the site. I have a long way to go to finish these plots, many more seed ticks to encounter and several more meetings with keys. I look forward to analyzing the successive years of data to see the changes through time, and to thank my boss for being such a great ecologist who valued data collection as much as I do.

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