Monday, January 28, 2008

Deep muck fen


Psychiatrists regard a patient's indifference to flowers as a symptom of clinical depression. It seems that by the time the singular beauty of a flower in bloom can no longer pierce the veil of black or obsessive thoughts in a person's mind, that mind's connection to the sensual world has grown dangerously frayed.
-Michael Pollan, The Botany of Desire


I realized today, zooming past limestone bluffs covered in icicles, that I haven't posted pretty pictures of flowers in several months. During the day, I'm learning my Ozark plants, trying to learn which plants grow in which community before they actually appear in the field. I'm doing this for several reasons, and not the least of which is that I hate having to ask my esteemed colleagues for plant identifications. So, I'm systematically going through all of the various habitats and learning all of the plants associated with them. Today I came across a great community, the deep muck fen, which is rich with rare, lovely flowers, several pictured, and all of which should remind us of the true splendor of spring.

More importantly, however, is that I'm formally declaring that the Ozark deep muck fen is possibly my favorite community right now (even though it sounds like a Vietnamese noodle dish). As of 10 a.m., deep muck fens knocked out the esteemed dry-mesic chert woodlands, my focus community for the past two weeks. I was gently reminded around 2 p.m. that the great Paul Nelson, my mentor and friend, the true Yoda to Chief's Obi-Wan (I aspire to be Luke), reclassified all of the Ozark fens. Now, officially, all fens are classified as (the unimaginative) Ozark fens with 2 subsections: deep muck and marly seep. Paul did this for a reason. Apparently, the plants in deep muck and seep overlap, with only a handful of true deep muck endemics (species found only in deep muck and not in seeps). Paul is a very deliberate man, and I'm sure he didn't take renaming the fens lightly. I imagine he had long, philosophical discussions about it, probably over campfires, late at night. These are decisions likely not made in a gray walled office.


Nevertheless, Ozark fens, on the whole are fascinating. Most fens in North America appear in the glaciated region of Canada and Minnesota. In the Ozarks, fens occur when mineralized groundwater is pulsed through dolomite rock layers downwards until the water comes out at a resistant bedrock layer. When the minerlized water reaches the surface, it creates a mucky, wet, cool environment. When the glaciers retreated from Missouri during the Pleistocene, several cool climate plants were left behind, many of them thriving in the constant, 56 degree waters of fens.

Because the water has moved through dolomite, it has high levels of soluble calcium and magnesium. Fen soil levels range from shallow to very deep, and plant fertility is, generally, very high. Deep muck fens, in particular, bog-like areas characterized by 15-40 inches (or more!) of deep mucky soils (officially called mucky sedge peat, formed by decomposing vegetative matter) and pools of standing water. They are characterized by sedges and wildflowers, with some areas harboring a diversity of shrubs. Several state listed rare and endangered plants and invertebrates appear only on these fens. When early travelers fell into them, they thought it was quicksand. In a landscape built on top of dolomite, limestone and sandstone, any community that boasts a rich soil layer is worth lauding.


For a deep muck fen to occur, the area must have a sufficient recharge and storage capacity that insures an uninterrupted groundwater supply. Too, just under the surface, there must be an impermeable layer of limestone, sandstone, or dolomite that impedes water movement. Deep muck fens generally occur at toeslopes (the concave or abrupt change in elevation at a hillslope base, usually composed of colluvium washed down from higher slopes) and in rich valleys, offering a constant source of water to breeding amphibians and birds like American bitterns and rails. In the Ozarks, with the right topography, with the right subsurface layers, fens appear! And based on their wildflower and sedge diversity, they're a sight to behold.


Like most freshwater wetlands in Missouri's Ozarks, deep muck fens are a rare occurrence. In fact, there are only eight in the whole state worth their salt in biodiversity. Most wetlands have been drained or otherwise damaged; one deep muck fen was used as a mudpit by mountain bikers until it was restored in the 1980s. The site will never be restored to its pre-destruction splendor, but some obligate sedges and wildflowers have moved in again.

Especially notable in the world of deep muck fens is Blair Creek Raised Fen, located in eastern Shannon Co, one of the prettiest counties in the state (top three: Shannon, Carter, Taney, all in the Lower Ozarks). This fen is found at the base of a wooded slope and it represents the only known raised deep muck fen in the state. The thick soil and organic material deposits have swollen above the surrounding flatland. Within this curious development grow the state listed rare marsh blue violet and orange coneflower. It has been estimated that Blair Creek Raised Fen is 4,000 years old, slowly building its soil layer, protected by its presence within the Mark Twain National Forest.

The hydrology of fens is largely unknown. Fen groundwater doesn't necessarily correlate with the surface water recharge area. Nevertheless, precautions should be made to protect the watersheds around these rare communities. The delicate nature of water quality in fens directly impacts the amphibians and diverse invertebrate lives that call these communities home. Many fens are threatened by alterations in hydrology, what with landowners trenching and draining fens to allow more grazing of cattle on the rich soils. I'm reminded that all natural resource management really comes down to the soil layers. Areas with great soils are the first to be plowed and grazed, poor soil areas are the last. Deep muck fens, unfortunately, and as their name suggests, have great soils. Oh, but the diversity they produce! Those brightly colored ArcView soil maps are coming in handy already...

So, borrowed from Ozark fen fans, pictures of marsh violet, grass pink orchid (which shows up in droves after a spring burn in Louisiana's pitcher bogs), shining ladies tresses orchid, and Riddell's goldenrod, a state listed species. A little spring and autumn beauty on this 20 degree night.

3 comments:

Stephen said...

Hi-- I found your site when I typed in something like "Missouri sedge diversity." I have recently/temporarily moved to Ellington, MO (in the Current River Conservation Area) as a field tech--I'll be doing herp surveys in the spring and fall, and probably some veg work in the summer for the Missouri Ozark Forest Ecology Project. Anyway, it sounds like you would be a good person to ask about interesting natural features of Missouri. I am particularly interested in learning more about sedges, grasses, wildflowers, well anything of the natural world, really. Perhaps you would have some suggestions of how to find natural areas in Missouri, be able to suggest some places to visit, or perhaps you know of naturalist groups who take field trips every now and then? Please, do let me know!

Enjoy life,
Steve Caird

stephen.caird@gmail.com

Ted M. said...

Yes, I agree with your top 3 (Shannon, Carter, and Taney). Up there also must be Ste. Genevieve Co., despite the presence of its moderately large (albeit beautiful) namesake town, and Iron Co., with its igneous exposures is hard to ignore. Aw heck, what about Ripley Co. (Bald Hill Glade) - just a beautiful state!

Allison Vaughn said...

Okay, Ste. Genevieve is awesome. A few good wineries there, too. Ripley Co.'s Cupola Pond is a must. If bird voiced treefrogs are anywhere in Missouri, they are in Butler Co. I'm also really digging the chert woodlands of LaClede Co, despite that most of the county is in ag. production. Easier, the crummy counties...I can list them on two hands. You're smart, so I bet you can imagine what they are.