Georgia’s Mountain Bogs: Rare Gems of the Southern Blue Ridge Mountain Bog. A “beaver-influenced” sedge meadow/stream/shrub swamp complex. Alan Cressler Although the pace of degradation has slowed J. Mincy Moffett, Jr., and Carrie Radcliffe in the last half century, forces continue to re- ountain bogs are among the rarest of all duce, fragment and threaten this most precious Mhabitat types in North America and are of natural communities. In 1995, a glimmer also one of the most threatened. Recognized of hope for mountain bogs would arrive in the as biodiversity hotspots supporting numerous form of a new and passionate group dedicated rare biological elements, they were likely never to plant conservation: the Georgia Plant Con- common across the landscape. They are even servation Alliance (GPCA). The GPCA co- rarer today as a result of the tremendous habi- alesced around the early conservation efforts of tat degradation throughout the southern Ap- the “Bog Fathers” at two mountain bogs. This palachians beginning in the mid-19th century. is their story. Tipularia • 2016 27 compressed, partially decomposed vegetable matter supplied by bog plants, potentially ac- cumulating over centuries or even millennia. The sphagnum mosses, of which Georgia boasts twenty species, are the greatest contributor. The cool, wet, acidic nature of bogs promotes anaerobic and antiseptic conditions, severely limiting the decomposition of plant matter. Peat’s thick deposits are mined throughout the northern hemisphere for use as both fuel and as a soil amendment, the latter known com- monly as “peat moss” and capable of holding 20+ times its weight in water. Sphagnum moss can form living mats six inches deep, as well as Rebecca Byrd/DNR mounding tussocks of a foot or more, capable Dense sphagnum mat. Monitoring a Swamp Pink of covering logs, micro-topography, and even safeguarding microsite. small plants. Invariably, the question arises as to whether Mountain Bog Primer our bogs are actually bogs or fens. The classical Mountain bogs, the Georgia variety, are wet- distinction was based exclusively on hydrology, lands situated in relatively flat topography and and was developed using northern ecosystem poorly drained soils of the Southern Appala- models. Traditionally, bogs are defined as peat- chians. The majority of the intact mountain lands having only precipitation as a hydrologic bogs are found between 2,500 and 3,500 feet. source and are referred to as ombrotrophic a.s.l. Soils are both mineral and organic in na- (cloud-fed). Bogs collect acidic rainwater and ture, although deep organic soils, characterized generate humic acids from their peat. Since by some depth of peat accumulation, are most they are unable to purge their acids (i.e., no common. Mountain bogs vary considerably in flow-through) they become and remain very their appearance, especially vegetative structure acidic (pH 3-4.5). Fens, on the other hand, and composition, owing principally to differ- have at least one hydrologic input in addition ences in bog origin, hydrology, disturbance re- to precipitation (i.e., groundwater, seep, etc.), gime, and historic land use. and are termed minerotrophic (mineral con- Bog hydrology is complex and varies among taining). Thus, they reflect the chemistry of the sites, being affected by both surface flows (seeps, geologic substrate through which they flow. springs, creeks, overland flow from floods), Fens can be either acidic “poor fens” (pH 4.6- subsurface flows (groundwater exchange), as 6.0) or neutral/alkaline “rich fens” (pH 6.1- well as direct precipitation. Mountain bogs de- 8.0), depending on the substrate. Erosion of velop in association with seepage slopes, spring- the acidic mountain bedrock of Georgia gener- heads, small order stream alluvial floodplains/ ally results in the creation of poor fens. There old channel beds, and beaver swamps/ponds. is also the floristic consideration. Vegetatively, Most mountain bogs in Georgia have multiple many mountain bogs (or sections of mountain hydrologic inputs and support multiple habitat bogs) more closely resemble ombrotrophic types, thus the term “mountain bog complex” bogs than minerotrophic fens, despite fen-like is frequently applied to them. hydrology and pH. Consequently, mountain Nearly all mountain bogs in Georgia possess bogs in Georgia can be viewed from varying some coverage by sphagnum moss and some perspectives: hydrologically as fens (almost all), degree of peat development. Peat is the layered, chemically as poor fens (most), and floristically 28 Tipularia • 2016 as bogs (many to most). The authors prefer the ests, to shrub bogs, to herbaceous/graminoid colloquial use of the term bog to describe all meadows, to sphagnum flats; all perhaps in- of Georgia’s mountain peatlands (or wetlands terspersed to some degree by open/flowing wa- with sphagnum), while acknowledging the ter. Dominant tree species include Red Maple definitional challenges and nuances of the bog (Acer rubrum), Tulip Tree (Liriodendron tulip- vs. fen debate. ifera), Black Gum (Nyssa sylvatica), and White Beaver are thought to play an important Pine (Pinus strobus). Pitch Pine (Pinus rigida), role in many mountain bog systems, even if a highly desirable species promoting a fire not currently present. Historically, beaver were regime, is relatively uncommon within bog- more abundant than today. They dammed propers. Less common species that add showi- mountain streams, creating ponds and killing ness or interest to the bogs include serviceberry woody vegetation. Periodically, they aban- (Amelanchier arborea), Sweet Birch (Betula doned their ponds, and their untended dams lenta var. lenta), American Holly (Ilex opaca), broke, exposing muddy flats. These were quick- Cucumber Magnolia (Magnolia acuminata), ly colonized by the sphagnum moss, wetland and Fraser Magnolia (Magnolia fraseri). Domi- herbs, and graminoids already present in the nant shrub species are Tag Alder (Alnus serrula- beaver swamp ecotone. These “sphagnum flats” ta), Mountain Laurel (Kalmia latifolia), Great constituted an embryonic bog that developed Laurel (Rhododendron maximum), and Possum over time as peat increased and floral diversity Haw (Viburnum nudum). Where present, the matured. Open sphagnum bogs gradually suc- following shrubs can become robust thick- ceeded to a shrub bog or even a swamp for- ets: Black Chokecherry (Aronia melanocarpa), est if succession was not interrupted or reset. Winterberry (Ilex verticillata), Mountain Dog- A return of beaver could completely reset the hobble (Leucothoe fontanesiana), Maleberry system, while other ongoing disturbances (Lyonia ligustrina), and Northern Wild Raisin could retard succession (e.g., large mammal (V. cassinoides), the latter at higher elevations. herbivory, periodic wildfire, or Native Ameri- Frequent showy shrubs include Mountain can activity). It is possible that some bogs have Sweet-pepper Bush (Clethra acuminata), Sweet lived, died, and been reborn hundreds of times. Azalea (Rhododendron arborescens), Swamp Regardless, the lifespan of any single bog (as Rose (Rosa palustris), and Common Elder- measured by a continuous stretch of time unin- berry (Sambucus canadensis). Common herbs terrupted by intervals of conversion to another are White Turtlehead (Chelone glabra), Orange habitat type), is relatively short, possibly mea- Jewelweed (Impatiens capensis), Cardinal Flow- sured in decades. er (Lobelia cardinalis), Tear Thumb (Polygonum Vegetation is remarkably varied among sagittatum), Swamp Aster (Symphyotrichum pu- mountain bogs along both bog-fen and woody- niceum), Roughleaf Goldenrod (Solidago patu- herbaceous gradients. Soil and hydrologic con- la), and Primrose-leaved Violet (Viola primuli- ditions (e.g., sodden soils, low pH, low nutrient folia). Graminoids dominate the understory of levels) in the “bog proper” restrict the types of sedge meadows with Prickly Bog Sedge (Carex plants able to establish in such habitats. Never- atlantica), Fringed Sedge (C. crinita), northern theless, bog flora is well suited to these realities Long Sedge (C. folliculata), Greater Bladder with adaptations for low nutrient conditions, Sedge (C. intumescens), Bristlystalked Sedge (C. including nitrogen fixation (e.g., alders), my- leptalea), Shallow Sedge (C. lurida), Three-way corrhizal associations (e.g., laurels and rhodo- Sedge (Dulichium arundinaceum), Fowl Man- dendrons), and carnivory (e.g., pitcher plants nagrass (Glyceria striata), Common Rush (Jun- and sundews). cus effususssp. solutus), Rice Cutgrass (Leersia Habitat types associated with mountain oryzoides) Brownish Beaksedge (Rhynchospora bogs range from full canopied swamp for- capitellata), Woolgrass (Scirpus cyperinus), and Tipularia • 2016 29 Leafy Bulrush (S. polyphyllus). Less common Over two million acres, across 15+ counties in grasses, yet good mountain bog indicators, are extreme northeastern Georgia, were remotely Slender Mannagrass (Glyceria melicaria) and surveyed and analyzed. Only 1,160 acres (from Seep Rush (J. gymnocarpus). Common ferns 330 sites) qualified as potential mountain bog/ include Sensitive Fern (Onoclea sensibilis), Cin- wetland sites (<0.06%) (Figure 1). namon Fern (Osmunda cinnamomea), Royal Extensive ground-truthing of these sites, led Fern (Osmunda spectabilis), and New York Fern by DNR biologist Thomas Floyd, determined (Thelypteris noveboracensis). And, of course, that only eighty-five of these were currently, ,sphagnum mosses (Sphagnum spp.). or likely had been recently, mountain bogs. Mountain bogs