Thursday, October 25, 2012

An Ecosystem Destroyed

For the past few months, in my spare time, I've been assisting a colleague with the monumental task of mapping all of the glades in Missouri. The methodology is a little tedious, but the project is incredibly fun and rewarding. Among the best part of mapping glades is the field verification, randomly selecting a glade that may actually be an old field and not a glade at all. Of course, in trickier situations like in the Springfield Plain, little glades can be situated smack in the middle of an old field. Those, too, can be mapped after they've been verified.

There are thousands of privately owned glades in Missouri, so verification entails meeting private landowners to ask for permission to check out their property. Most folks are really excited that someone with an interest in botany wants to see their land. In fact, everyone I've met has been stellar, very friendly and helpful, and usually thrilled to tell me about the yellow coneflowers in spring, and the tall flowers of prairie dock that appear each summer on their glade. A lot of landowners have never heard of glades, but they know that they own some sort of ecosystem that looks different from the surrounding landscape

One recent field verification trip took me to a geologic anomaly around Decaturville. On the wall behind me is a massive 1979 Geologic Map of Missouri, and at Decaturville is a handdrawn circle with a few lines emanating from the sides. It was once thought that a meteor landed there, which accounts for the strange geology and landforms; for example, LaMotte sandstone shows up here pocked in the landscape, surrounded by a sea of dolomite. I have a vague recollection that this was not the site of a meteor crater, but an erosional feature of downcutting (the LaMotte sandstone that appears on geology maps? It's exposed in a pit created when the area was mined for uranium). Nevertheless, the area is characterized by interesting geology, so I was particularly interested to see the huge band of glades that exist on the different geology outside of Decaturville. No LaMotte sandstone barrens here in the Central Ozarks of Niangua country, just an abandoned pit with some sandstone exposed.

After climbing over and under barbed wire fences, we hiked through the post oak woods that day and encountered a massive glade belt, dotted with askew dolomite boulders sitting in a circle:



This was a massive glade belt with some curious geology, but that barbed wire fencing was still being maintained to keep a massive herd of cows grazing there. The glades were totally trashed from grazing, with absolutely no soil left and only a hint of the warm season grass structure. It's a little grim to conduct field verification to find that what was once most likely a significant landscape feature has been so intensely damaged by grazing or some other destructive process. I took a lot of glade photos that day but couldn't find a single stem of Rudbeckia missouriensis or, well, any other forb.  

In a recent comparison analysis of FQI on glades in the White River Hills, it has been determined that the floristic integrity--damaged by many years of grazing--is slightly improving (ever slowly) since the cows and grazing allotments were removed from the glades. Having conducted floristic surveys in damaged systems in the Ozarks, I have learned that damage such as at this glade belt is not easily reversed. Ecosystems are not "dynamic and ever changing," and nor are they "resilient" when they've been damaged so severely. It won't be in my lifetime that this glade will recover a thick thatch layer and sod which supports a biodiverse glade flora, even if the cows were taken off this week.  But we verified it was a glade, destroyed, but still a glade.

3 comments:

Justin R. Thomas said...

Another great story, Allison; though a sad one. I especially like the point you illustrate about the restoration potential and perceived "resilience" of natural systems. There is a major misconception in the conservation/ecology fields that systems can be restored simply by removing disturbance and/or reintroducing fire. While structure and diversity (in the academic sense) can be increased by such measures, rarely does species richness or net floristic quality show improvement. Once local extinctions are initiated, there is little hope for recolonization of conservative species since many are there as the result of past climates or floristic shifts measured in geologic terms. This is a fundamental tenant of the FQA process and too often forgotten or ignored by the hopeful, as opposed to skillful, practitioners of ecological management. This is why saving the remnants, NO MATTER HOW SMALL, is so crucial to sustaining natural integrity and why the fairly recent shift to an ecoregional focus, at the expense of a local focus, in conservation is likely a bad idea.

James C. Trager said...

When I read this sort of essay, I am reminded of leopold's statemtn that we live in a "world of wounds".
I have a question about this, for both you and Justin: "Of course, in trickier situations like in the Springfield Plain, little glades can be situated smack in the middle of an old field." Are these glades in fields (maybe, former prairies?) what Paul Nelson calls dry-mesic limestone/dolomite prairie? From their descriptions, I find it hard to distinguish the latter from calcareous glades, other than by context.

Allison Vaughn said...

Well, looking at the historic GLO notes from Springfield Plain country (Greene Co., Willard, that part of the state), the landscape had native prairie historically, but it also had open woodland and savanna--mostly chinquapin oak and post oak dominated. The glades that are there are clearly bedrock communities. While glades tend to have prairie vegetation, prairies have a soil layer significantly deeper than glades. Our mapping project allows us to see bedrock through infrared which makes it possible to tell a glade from the rest of the field. This neck of the Ozarks houses the motherlode of Missouri bladderpod, which tends to be found on glades in the middle of fields.