Saturday, September 21, 2013

Glade Verification

The glade mapping project I’ve been engaged in for more than four years is coming to a close, with over 85,000 glade polygons mapped. While it’s unrealistic to step foot on each mapped glade, field verification has shown that the methodology we’ve employed has worked well. Most recently I learned that there are hundreds of glades around Tuscumbia and St. Anthony, though driving through the area I never would have suspected this rolling country would harbor so many—of questionable quality like most glades in Missouri, but glades by definition. The same situation occurs around Truman Lake in the Western Ozarks where hundreds of glades rest quietly, waiting for restoration.

But in the intergrade region of the Cole Camp quadrangle, where the former prairies meet the Ozarks, the line of demarcation between former prairie and rocky, dry woods that support shallow bedrock communities depends more on the topography than on any signature one can glean from infrared and leaf-off images. The quadrangle is literally split in two: wooded hillsides with a few scattered glades in the southern part of the quad, and overgrazed pasture with little elevation change and barely a shred of native vegetation in the north half. Regardless, row by row, I look for glades, scanning for the signatures.

Using only the infrared imagery, cedar-choked woods on broad, flat pastured plains can carry the glade signature. However, the methodology includes close examination of other layers on ArcView. In the Cole Camp quadrangle, the topography helps tremendously to tell the story to delineate glades covered in cedars and flat ground old pasture covered in cedars. But then I thought about the Springfield Plain and all of those little limestone glades in the middle of gently undulating fescue pastures. Or the sandstone glade that provides a scenic overlook in the middle of a tallgrass prairie with a high quality stream below. The vegetation is more aligned with a glade than a prairie (for example, it’s the only place in 3,000 acres that I encountered Coreopsis palmata; it’s C. grandiflora country throughout the landscape). In the Cole Camp quad, I’m going to trust my judgment that the glades are in the southern portion with the wooded Ozark country, and the north is dominated by pastures with wall-to-wall cedars. Perhaps on my way to Eichenberg Winery I’ll do some field verification just to make sure.

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