We saw the problem on the first east facing glade belt we walked on: feral hog damage and constant pressure from deer browse. You see, unlike the rest of the White River country, somehow these glades were slightly spared the utter devastation caused by 80-100 years of grazing by domestic livestock. Three years ago, these glades, unlike other glades in the area, had a thick grass structure and a deep layer of sod formed by years of thatch buildup. All the traditional dolomite glade plants were there in the matrix. So, I guess we were utterly despondent, grouchy, crochety and cranky, totally and resolutely bummed when we hit the next belt of glades and they looked like this:
Of course, if this image came from a garden, someone's yard planting, I would congratulate them for creating pretty planting of four species. However, this is a glade, and it is out of context with its historic character from only a few years ago. High quality glades are diverse ecosystems with a dominant grass structure (little and big bluestem, Indian grass, Sporobolus heterolepis) with perennial forbs in the mix. The Relative Importance Value of grasses on glades is extremely high, and grasses influence the soil structure (which in turn influences everything that grows). Look down at the ground past the four pretty flowers on these White River Hills glades and you'll see this:
Chert rubble. Thanks to a resident population of feral hogs, there is no soil left on these glades. They have managed to destroy the grass layer on these glades, and without the warm season grasses that are the lifeblood of a dolomite glade, the soils eroded away leaving behind rubble and four, maybe five, species of perennial forbs. Those of you familiar with Missouri flora will recognize the tall blue delphinium in the photo above: Trelease's larkspur, historically conservative in Missouri because of the sad shape of White River glades. But you see, Trelease's larkspur traditionally grows on depauperate rock outcrops on glades, not in the place of warm season grasses in the middle of the glade. Trelease's larkspur doesn't like competition, so historically it was restricted to dry rock outcrops where grasses and other forbs can't grow. Here, with no competition from grasses or the rich matrix of dolomite glade plants (because the hogs rooted them up and successive rain events have sent the glade soil into the valley), Trelease's is taking off in the absence of everything else. It's an artificial setting reminiscent of a garden.
Some who care about rare plants may think this is just fine--feral hogs have inadvertently "created habitat" for an uncommon wildflower (uncommon in the state but locally abundant in its southwest Missouri range thanks to overgrazed glades with no soil). Trelease's larkspur is doing just fine in the hog and deer-infested White River Hills damaged landscape. Conversely, purple coneflower grows really well in my mom's garden, another artificial setting. But this explosion of plants is at the expense of the glade ecosystem. The wildflowers on these glades are actually a crop of 5 species: wild onion, pale purple coneflower, Trelease's larkspur, calamint, and maybe a rare-to-these-glades-now Heliotropium tenellum. Even today, years after the publication of the Terrestrial Natural Communities of Missouri (which cements the ecological concept that all facets of an ecosystem work together to create a whole community), there are some who still sprinkle wildflower seeds on existing glades to create a glade setting despite what the natural landscape harbors naturally. Often this is done without any research indicating that these plants were ever there, and whose genetics do the seeds come from? Glades in Missouri are distinctive, and they all have their own histories of abuse from grazing, quarrying, being used as roadbeds, and so forth. The sandstone glade outside of Springfield that for the past thirty years has not had Missouri bladderpod growing on it now does because seeds were scattered there. On what authority? How does anyone know if that was a bladderpod flurry site? And why tinker with a native ecosystem? With a long restoration regime some of those conservative elements can come back on their own, once that sod layer is built up again. Frankly, I don't agree with the Johnny Appleseed approach to ecosystem management. I think it's artificial and it messes with the genetics of these ancient systems. (And then, three years from now, someone will fill out an Element of Occurrence Record to the Natural Heritage Database for some fake population, thereby compromising the integrity of the Heritage Program.)
Visit the thousands of acres of overgrazed glades in the Ozarks and you'll likely see the same thing--a bed of chert rubble on top of exposed bedrock with scattered plants and, in the sampling frame, a lot of "bare soil/rock" filling up most of the sampling pages. Oh, there may be 4 species per frame, all with low cover values. Today the hogs, more livestock in native ecosystems, are picking up where the cows left off at the end of open range grazing. In terms of causing massive erosion and utter destruction to these fragile landscapes, the hogs are the nail in the coffin of an indefensible relict that once represented a heterogeneous landscape before the constant pressure of cows, hogs, goats, and sheep destroyed thousands of the surrounding acres.