Potential Disconnect Between Observations of Hydrophytic
Vegetation, Wetland Hydrology Indicators, and Hydric Soils in
Unique Pitcher Plant Bog Habitats of the Southern Gulf Coast
Jacob F. Berkowitz, Sanderson Page, and Chris V. Noble
Southeastern Naturalist, Volume 13, Issue 4 (2014): 721–734
Full-text pdf (Accessible only to subscribers.To subscribe click here.)
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22001144 SOUTHEASTERN NATURALIST 1V3o(4l.) :1732,1 N–7o3. 44
Potential Disconnect Between Observations of Hydrophytic
Vegetation, Wetland Hydrology Indicators, and Hydric Soils in
Unique Pitcher Plant Bog Habitats of the Southern Gulf Coast
Jacob F. Berkowitz1,*, Sanderson Page2, and Chris V. Noble1
Abstract - The Sarracenia spp. (pitcher plant) bogs located along the southern Gulf of Mexico
represent a unique natural resource characterized by endangered and endemic wetland
floral communities that include a number of carnivorous plants (e.g., pitcher plants and Drosera
spp. [sundews]). Despite the prevalence of obligate wetland plant species and indicators
of wetland hydrology, the soils underlying this niche ecosystem often lack clear indicators of
hydric soil morphology, posing challenges to wetland delineation and resource management.
The National Technical Committee for Hydric Soils and an interagency team of soil scientists
investigated saturated conditions and anaerobic soil conditions in pitcher plant bogs. Our
results demonstrate that many of the pitcher plant-bog soils examined failed to meet an approved
hydric soil indicator. Herein, we discuss potential factors preventing the formation of
typical hydric soil morphologies including: low organic-matter content, high iron-concentrations,
extensive bioturbation, presence of high-chroma minerals (e.g., chert), and short
saturation-intervals. Our examination of soil morphology and condition in these unique and
ecologically valuable habitats indicates that additional studies are required to address the apparent
disconnect between observations of soils, hydrophytic vegetation, and indicators of
wetland hydrology to ensure the appropriate management of these endemic natural resources.
Introduction
The lower Gulf Coastal Plain of Alabama, Florida, Louisiana, and Mississippi
contains Sarracenia spp. (pitcher plant) bogs, including communities referred to as
wet Pinus spp. (pine) savannahs, Fallicambarus spp. (crawfish) flats, pine flatwood,
pitcher plant prairie, and grass–sedge bog (FNAI 1990, Wharton 1978). Multiple
carnivorous plant species, including pitcher plants and Drosera spp. (sundews) consistently
occur in these ecosystems (Fig. 1a; Smith 1988). Under natural conditions,
sparse overstory canopies of Pinus palustris Mill. (Longleaf Pine) and/or Pinus elliotti
Engelm. (Slash Pine) underlain by a diverse community of forbs and grasses
characterize these areas. Many species of orchids, lilies, and grasses (some rare,
endangered, and endemic) are only found in this ecological niche (Folkerts 1977).
The natural ecology of bog communities remains extremely sensitive to disturbance
brought about by soil manipulation, fire suppression, and alteration of the hydrology
(Harper et al. 1998). In the absence of fire, pines and large shrubs encroach on
these areas, resulting in changes to species diversity and a build-up of biomass and
1US Army Corps of Engineer Research and Development Center, Vicksburg, MS 39180.
2US Department of Agriculture Natural Resources Conservation Service, Loxey, AL 36551.
*Corresponding author - Jacob.F.Berkowitz@usace.army.mil.
Manuscript Editor: Julia Cherry
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Figure 1. a) Sarracenia leucophylla (White-topped Pitcher Plants) flourish after a recent
prescribed burn, b) typical landscape setting within the study area, c) deep and d) shallow
soil profiles. Note that surface layers exhibit high chroma (≥3) but contain many redoximorphic
features common to hydric soils. Subsurface layers are characterized by prominent
iron concentrations and the accumulation of clay capable of supporting a high water table
and hydrophytic vegetation.
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fuel (Brewer 1999). Increased fuel loads often result in less frequent but extremely
hot, ecologically damaging fires (Frost et al. 1998, Huffman and Blanchard 1990).
Additionally, increased rates of bioturbation are reported in the study area, with
densely occurring crawfish burrows observed at many pitcher plant bogs (Folkerts
1990). Pitcher plant bogs are often underlain by clay materials at depths less than 50
cm (20 in), a feature that impedes drainage and promotes perched high water tables
and the development of wetland hydrology (Folkerts 1991, Schafale and Weakley
1990). Many soils in pitcher plant bogs remain highly weathered and very acidic
(Plummer 1963, Wells 1971), and fire regimes impact nutrient abundance and availability
(Mckee 1982).
Pitcher plant-bog ecosystems are widely distributed across certain parts of the
landscape (Fig. 2a). Soil scientists and federal agency personnel reported that many
soil pedons in pitcher plant bogs lack a hydric soil field-indicator when the hydrology
and hydrophytic plant community indicate wetland conditions. For example,
two soil series (Tibbie and Pinebarren) established in Washington County, AL, appear
to meet wetland hydrology and hydrophytic vegetation criteria, but often fail
to display characteristic hydric soil morphology (USDA-NRCS 2013) exhibiting
high chroma (i.e., ≥3) within near-surface layers (Fig. 1). In this study, we present
the results of investigations of the lack of hydric soil field-indicators, through
Figure 2. a) Potential pitcher plant-bog communities of southwest Washington County,
AL, projected on a hillshade reflief map. Soil-map units are: AtA–Atmore fine sandy loam,
0–2 percent slopes; AtC–Atmore fine sandy loam, 2–8 percent slopes; and TPB–Tibbie and
Pinebarren soils, 1–5 percent slopes. b) Site locations relative to geologic surface-units on a
composite map. The Sandhill Crane Refuge study area occurs on a young Holocene/Quaternary
terrace (Qc) near the contact with the Pliocene Citronelle formation. The Washington
County study area occurs on the Tertiary Miocene (Tm), and Splinter Hill Bog occurs near a
contact of the Citronelle Formation and the underlying Miocene, undifferentiated unit (Tm).
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application of the hydric soil technical standard (NTCHS 2007), in pitcher plant
bogs and discuss potential causes of the observed soil morphology and barriers to
hydric soil indicator expression.
Study Sites and Methods
The National Technical Committee for Hydric Soils (NTCHS) retains the responsibility
for establishing field indicators of hydric soils in the US (Vasilas et al.
2010). During 2011, local US Army Corps of Engineers (USACE) personnel and
Natural Resources Conservation Service (NRCS) soil scientists identified the issue
of high chroma soils in pitcher plant bogs and requested that NTCHS conduct a
study and field visit to the affected area. As a result, local soil scientists identified
3 areas for investigation (Fig. 2b).
The Mississippi Sandhill Crane National Wildlife Refuge study area in Jackson
County, MS, is located in land resource region (LRR) P, near the contact of
the major land resource areas (MLRA) 133A and 152A—Southern Coastal Plain
and Eastern Gulf Coast Flatwoods, respectively (USDA-NRCS 2006). This site is
6 m (20 feet) above sea level on a relatively young (Holocene/Quaternary) marine
terrace. The area occupies a low-lying, nearly level terrace drained by Taxodium
(cypress)/Liquidambar (gum) swamps. Hydrology of the terrace (recharge area)
and the swamps (discharge area) is governed by the nearby Pascagoula River
(USDA-NRCS 2013). Rainfall, the nearly level topography, and low relief govern
local site hydrology.
The Washington County study area is located near the town of Tibbie, AL, and
The Nature Conservancy’s Splinter Hill Bog study area is in Baldwin County, AL;
both occur at elevations above 60 m (200 feet) and exhibit open drainage systems.
The sites feature older, more dissected landscapes, situated within MLRA 133A.
Hydrologic periodicity remains complex because of the number of tributaries that
contribute to subsurface and surface-water movement (USDAS-NRCS 2013).
Onsite hydrology is governed by stream-order complexity, the impermeable substratum,
landscape position, and topography. The sites occur on nearly level to
gently sloping flow-through and discharge areas on foot slopes and toe slopes.
As seen in Figure 2a, the pitcher plant bogs examined occur in close proximity to
the established Atmore series: coarse-loamy, siliceous, semiactive, thermic Plinthic
Paleaquults; the newly documented Tibbie series: fine-loamy, mixed, semiactive,
thermic Plinthaquic Paleudults; and the newly documented Pinebarren series:
coarse-loamy, siliceous, semiactive, thermic Plinthaquic Paleudults.
We identified two sample points at each location and completed soil descriptions
according to the regional supplement to the USACE wetland delineation manual
(Wakeley et al. 2010). We excavated all soil profiles using a spade until we reached
a restrictive clay aquitard. In addition, at all sites, we installed instrumentation
necessary for applying the hydric soil technical standard (HSTS; NTCHS 2007).
The HSTS requires data to 1) establish that soils display anaerobic conditions, and
2) demonstrate adequate saturated conditions during the growing season. We tested
for the presence of anaerobic conditions using indicator of reduction in soils (IRIS)
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tubes based on the methods of Rabenhorst and Burch (2006) and Berkowitz (2009).
We installed triplicate IRIS tubes at each sample location and if 2 out of 3 IRIS
tubes displayed 30% iron removal within a 15-cm (6-inch) zone, we considered
that the criteria for anaerobic conditions criteria set by the HSTS had been met. We
evaluated removal of Fe from IRIS tubes by using scanned digital image analysis
via binarization with Digimizer version 3.7.1 (Berkowitz and Sallee 2011). Other
studies have required that 3 out of 5 IRIS tubes must display iron removal in order
to be considered to have met criteria set by the HSTS (NTCHS 2007; Berkowitz
and Sallee 2011). We also tested soils with αα-dipyridyl dye to provide additional
data regarding anaerobic conditions (NTCHS 2009).
To measure saturated conditions, we used groundwater-monitoring wells installed
50 cm (20 inches) below the soil surface (Noble 2006, Sprecher 2008,
USACE 2005). We installed In-Situ Troll 500 (In-Situ, Inc., Fort Collins, CO)
automated data-logging equipment to monitor and record groundwater levels
twice daily. All equipment installation occurred in October 2012, and monitoring
continued until April 2013, thereby capturing the typical annual wet period within
the study area. We followed the recommendations of the NTCHS (2007) to analyze
HSTS results. Analysis of growing season and rainfall normality was based
on the findings of Sprecher and Warne (2000). We obtained precipitation data for
the 3-month period preceding and during the study period (USDA-NRCS 1997)
and used the direct antecedent rainfall evaluation method (DAREM) analysis to
determine rainfall normality (Sumner et al. 2009). Several local plant experts
documented vegetation data onsite to verify that a prevalence of hydrophytic
plants occurred within each study area (Schotz 2010; see Acknowledgments). Additionally,
we recorded indicators of wetland hydrology as outlined in the regional
supplement to the USACE wetland delineation manual (Wakley et al. 2010).
Results
Hydrophytic vegetation
Hydrophytic vegetation was dominant at all three study areas where frequent
prescribed burns are a recurring management tool. In relation to the number of plant
species present, the Sandhill Crane Refuge displayed the least diversity and lacked
an overstory canopy (Fig. 1b). Grasses—mostly Andropogon spp. (bluestem), Aristida
stricta Michx. (Pineland Threeawn Wiregrass)—and forbs were dominant. A
few low-growing shrubs including Ilex glabra (L.) A. Gray (Inkberry) and Gaylussacia
mosieri Small (Woolly Huckleberry) were also present. Obligate vegetation
included Sarracenia alata Alph. Wood (Yellow Trumpets), Lycopodiella appressa
(Chapm.) Cranfill (Southern Bog Clubmoss), Pogonia ophioglossoides (L.) Ker
Gawl. (Snakemouth Orchid), Helianthus heterophyllus Nutt. (Variable-leaf Sunflower),
and Pinguicula lutea Walt. (Yellow Butterwort).
The overstory canopy was sparse at the two study areas located in Alabama,
though Splinter Hill Bog contained a greater diversity of species. Longleaf Pine,
Slash Pine, and Magnolia virginiana L. (Sweetbay Magnolia) occurred on both
sites, as did Morella cerifera (L.) Small (Wax Myrtle), Inkberry, and Ilex coriacea
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(Pursh) Chapm. (Large Gallberry). Obligate wetland species present at both sites
included Sarracenia leucophylla Raf. (White-topped Pitcher Plant), Drosera capillaris
Poir. (Pink Sundew), Rhynchospora gracilenta A. Gray (Slender Beaksedge),
Utricularia subulata L. (Zigzag Bladderwort), Southern Bog Clubmoss, Variableleaf
Sunflower, Lachnanthes caroliniana (Lam.) Dandy (Carolina Redroot), and
Lophiola aurea Ker Gawl. (Goldencrest). In the Washington County study area,
additional obligate species included Sarracenia rubra subsp. wherryi F.W. Case &
R.B. Case) Schnell (Wherry’s Redflower Pitcher Plant), Eriocaulon compressum
Lam. (Flattened Pipewort), Drosera intermedia Hayne (Spoonleaf Sundew), and
Yellow Butterwort. Additional obligates in the Splinter Hill study area included
Nyassa biflora Walter (Swamp Tupelo), Sarracenia rosea F.W. Case & R.B. Case
(Purple Pitcher Plant), Ludwigia virgata Michx. (Savannah Primrose-willow),
Rhynchospora ciliaris (Michx.) C. Mohr (Fringed Beaksedge), Xyris ambigua Bey
ex. Kunth (Coastal Plain Yelloweyed-grass), Drosera tracyi Macfarlane (Tracy’s
Sundew), Helenium brevifolium (Nutt.) Alph. Wood (Shortleaf Sneezeweed), Xyris
difformis Chapm. (Bog Yelloweyed-grass), and Sarracenia leucophylla x S. purpurea
(a pitcher plant hybrid).
Saturated conditions and indicators of wetland hydrology
The saturated-conditions criteria of the HSTS require that the water table
remain within 25 cm (10 inches) for >14 consecutive days during the growing season.
The two Sandhill Crane Refuge sites failed to meet these criteria, with high
water-table events limited to between 5 and 6 days duration. Four study areas met
the hydrology portion of the HSTS (Table 1; Fig. 3), with hydrologic durations
ranging from 15 to 89 consecutive days. DAREM analysis results demonstrate that
the saturated-condition criteria of the HSTS were satisfied during normal or drier
than normal periods (Table 2; also see Supplemental Tables 1–18, available online
at https://www.eaglehill.us/SENAonline/suppl-files/s13-4-S2091-Berkowitz-s1,
and, for BioOne subscribers, at http://dx.doi.org/10.1656/S2016.s1).
Although HSTS criteria for saturated conditions were not met at 2 study sites, all
study areas displayed indicators of wetland hydrology (Wakeley et al. 2010). Each
location exhibited at least one primary and/or two secondary indicators of wetland
Table 1. Summary HSTS data indicating anaerobic conditions and saturated conditions. Days = consecutive
days of saturation
Parameter Summary
IRIS tubes
with >30% αα-dipyridyl Anaerobic Saturated
Study area removal reaction? Days conditions? conditions? HSTS met?
Sandhill Crane A 0/3 No 6 No No No
Sandhill Crane B 0/3 No 5 No No No
Washington County A 2/3 Yes 89 Yes Yes Yes
Washington County B 1/3 Yes 15 No Yes No
Splinter Hill A 3/3 Yes 37 Yes Yes Yes
Splinter Hill B 0/3 No 28 No Yes No
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Figure 3. Wetland hydrologic-monitoring results collected at a) Sandhill Crane Refuge A,
b) Sandhill Crane Refuge B, c) Washington County A, d) Washington County B, e) Splinter
Hill A, and f) Splinter Hill B. The horizontal lines represent periods when the HSTS
saturated-conditions criteria were met. All saturated conditions occurred during normal or
dryer than normal rainfall periods as indicated in Table 2 (also see Supplemental Tables
1–18, available online at https://www.eaglehill.us/SENAonline/suppl-files/s13-4-S2091-
Berkowitz-s1, and, for BioOne subscribers, at http://dx.doi.or g/10.1656/S2016.s1).
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hydrology. Observed wetland hydrology indicators included: B4, iron deposits;
B13, aquatic fauna, C3, oxidized rhizospheres along living roots; C4, presence of
reduced iron; B10, drainage patterns; C8, crawfish burrows; D2, geomorphic position;
and D5, FAC neutral test.
Anaerobic conditions and indicators of hydric soil
Four of the 6 areas examined exhibited some iron removal from IRIS tubes and/
or positive reactions with αα-dipyridyl dye (Table 1). Washington County B showed
iron removal from only 1 of 3 IRIS tubes, and a positive reaction to αα-dipyridyl
dye, indicating some level of anaerobic conditions. However, Washington County
B failed to meet the HSTS anaerobic conditions criteria because the duration of
reducing conditions was unknown and there was insufficient iron removal from the
majority of IRIS tubes. Two study sites—Washington County A and Splinter Hill
A—displayed >30% iron removal from 2 out of 3 IRIS tubes and met the HSTS
anaerobic conditions criteria. These sites also displayed a positive reaction with
αα-dipyridyl dye.
In general, soils within the study area displayed high-chroma colors beginning
either at the surface or below a dark layer (e.g., 10YR 3/1) ranging between
5 cm and 20 cm (2–8 in) thick (Fig. 4). We described loamy/clayey soil textures
during the site visit following Vasilas et al. (2010). All of the soil profiles we
examined exhibited 2–37% distinct or prominent redoximorphic concentrations
as pore linings and/or masses in near-surface layers. Additionally, several of the
profiles examined contained redoximorphic depletions. The presence of redoximorphic
features suggest that high water-tables and reducing conditions occur in
each study area.
Despite the presence of redoximorphic features in all soils, only one of the
soils (Splinter Hill Bog A) meets an approved hydric-soil indicator (F3–depleted
matrix). The lack of hydric soil indicators in all remaining sites results from the
presence of matrix chroma-colors ≥3 or inadequate depths to meet the requirements
of other hydric-soil indicators (e.g., F6–redox dark surface). Additionally, none of
the sample locations occurred in closed depressions subject to ponding, thus preventing
the application of hydric soil indicator F8–redox depre ssions.
Table 2. Rainfall normality-analysis results based on the DAREM approach. For each month during
the study period, the previous three months rainfall was evaluated and utilized to determine normality
as described in Sumner et al. (2009).
Month Sandhill Crane Refuge Washington County Splinter Hill
November Normal Wet Normal
December Dry Dry† Dry†
January Normal Normal† Normal†
February Dry Normal† Dry†
March Normal Wet Normal
April Normal Dry Normal
†indicates the months during which a minimum of 14 consecutive days of saturated conditions occurred
(NTCHS 2007).
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Discussion
Hydric soils typically exhibit morphological characteristics used, in conjunction
with the presence of hydrophytic vegetation and indicators of wetland hydrology,
to identify wetland boundaries. Hydric-soil characteristics form the basis of the
Figure 4. Near-surface soil descriptions collected within the study area. *Note that only one
soil profile (Splinter Hill Bog A; F3–Depleted Matrix) meets the criteria of an approved
hydric soil field indicator. All other profiles failed to meet the criteria for a hydric soil indicator
due to the presence of high chroma (≥3) colors. All soil profiles contain evidence of
redoximorphic processes including: concentrations (C) and depletions (D) occurring in pore
linings (PL) and within the soil matrix (M).
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hydric soil field-indicators and include the: 1) accumulation of organic materials
near the soil surface, 2) reduction, translocation, and re-precipitation of iron and
manganese oxides, and 3) formation of low-chroma (i.e., grey) colors within the
soil matrix (Mausbach and Richardson 1994). However, some hydric soils lack
these characteristics and require additional investigation (Megonigal et al. 1993,
Rabenhorst and Parikh 2000, Tiner 1999, Vepraskas and Sprecher 1997).
The vegetation and hydrology results presented above suggest that wetland
processes occurred within each of the study areas. Notably, all study sites displayed
indicators of wetland hydrology (e.g., crawfish burrows) and hydrophytic
vegetation (e.g., predominance of many obligate plant species): characteristics
that support a wetland determination (Tiner 1999). However, many of the soils we
examined lacked the characteristic morphologies associated with hydric soils. Several
scenarios provide potential explanations for the apparent disconnect between
observed site conditions (e.g., obligate hydrophytic plants, wetland hydrology
indicators) and the absence of hydric soil indicators. Factors preventing the formation
of hydric soil morphologies at these sites include: low organic matter content,
high iron concentrations, extensive bioturbation, presence of high-chroma minerals
(e.g., chert), and short saturation intervals (Vepraskas and Sprecher 1997). These
factors potentially work independently or in concert to limit the formation of hydric
soil field-indicators within the study area.
Many of the study areas examined display low surficial and near-surface organic
matter contents as indicated by the lack of dark soil horizons (i.e., values
≤2). Under normal wet-soil conditions, organic matter accumulates as moisture
increases (Daniels et al. 1971). In wet soils, organic matter accumulates due to
water logging, soil acidity, low oxidation-reduction potential, and other factors
(Fanning and Fanning 1989), and the amount of organic matter can be inversely
related to the number of wetting and drying cycles. Groundwater-monitoring results
displayed a high frequency of wetting and drying events, and the study areas
lacking hydric soil indicators were characterized by short-duration, rapidly rising
and falling water tables (Fig. 3a, b). Additionally, the surface vegetative cover
consists of sparse assemblages of shrubs, grasses, and forbs which provide little
organic matter residue, especially under a periodic regime of natural and prescribed
fires. Further, extensive bioturbation from crawfish continually churned
the surface and promoted bacterial respiration of organic matter through increased
exposure to warm temperatures, sunlight, and oxygen. The frequency of wetting
and drying cycles, lack of organic matter inputs from above- and belowground
biomass, and increased bioturbation by crawfish potentially limited organic matter
accumulation and the formation of hydric soil morphology.
In addition to low amounts of organic matter, study areas exhibited high amounts
of iron as observed in plinthite masses, iron nodules and concretions, and iron films
seeping from discharge zones. It is possible that that the electro-redoximorphic
system governing soil reduction and morphology was overwhelmed with dissolved
iron. The very slowly permeable clay layers beneath pitcher plant-bog soils also
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2014 Vol. 13, No. 4
occurred below the neighboring upland soils, albeit at greater depth (USDS-NRCS
2013). In an area with >150 cm (60 inches) of mean annual precipitation, reduction
reactions can continue at depths well below the surface, providing a lateral
source of dissolved iron to low-lying wetlands (Blume 1988). Although additional
research is required, positive reactions to αα-dipyridyl dye coupled with the lack of
iron removal from IRIS tubes located in areas exhibiting high water tables provides
some supporting evidence for such an influx of dissolved iron at these sites.
One potential approach to address problematic hydric soils in the study
area includes the application of an existing hydric soil field-indicator in a
neighboring region, A16–coast prairie redox (currently approved for use in
MLRA 150A of LRR T; USDA-NRCS 2006, Vasilas et al. 2010). Application of
A16 requires “a layer starting within 15 cm (6 inches) of the soil surface that is
at least 10 cm (4 inches) thick and has a matrix chroma of 3 or less with 2 percent
or more distinct or prominent redox concentrations occurring as soft masses
and/or pore linings”. The associated user notes mention that these hydric soils
occur on depressional landforms and associated intermound landforms of the
Lissie Formation—a deltaic plain of sand, silt, and clay of Pleistocene age. The
user notes further explain that “Chroma-3 matrices are allowed because they
may be the color of stripped sand grains or because few or common sand-sized
reddish chert particles occur and may prevent obtaining chroma of 2 or less.”
It should be noted that we observed chert particles in several of the study areas
examined, potentially diluting the observed color and leading to the designation
of high chroma for the pitcher plant-bog soils examined. As mentioned above,
extensive bioturbation by crawfish provides another potential mechanism for the
introduction of high-chroma subsurface materials into surface layers. Further examination
indicates that several of the study areas lacking a hydric soil indicator
would meet the requirements of A16–coast prairie redox. These findings suggest
that A16 may provide a useful resource within pitcher plant bogs. However, additional
data including the quantification of chert abundance will be required to
determine the extent and reliability of A16 throughout the region, and further
investigations are required to understand the mechanisms governing hydric soil
morphology in the pitcher plant bogs studied.
Whether addressed through the application of hydric soil indicator A16 or
another approach, the data presented above indicate that additional research is
required to fully reconcile the observed inconsistency between soils, hydrophytic
plants, and indicators of wetland hydrology in pitcher plant bogs. The current
study provides data indicating that high water-tables and some degree of anaerobic
activity (e.g., redoximorphic features in soil profiles) occurred within the study
sites. Additionally, we suggest a number of potential mechanisms preventing the
formation of hydric soil morphologies. Future studies should focus on long-term
monitoring of hydrology, plant distribution, and oxidation-reduction potentials.
These data, in addition to examinations of soil chemistry and mineralogy, will improve
management of unique pitcher plant-bog ecosystems.
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2014 Vol. 13, No. 4
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Summary
The ecological factors that support pitcher plant-bog habitats are unique and
not fully understood. Many of the soils associated with these ecosystems lack field
indicators of hydric soils despite the presence of hydrophytic vegetation and indicators
of wetland hydrology. Collected data demonstrates that some study areas meet
the HSTS, yet retain high-chroma matrixes characteristic of non-wetland soils.
We suggested several potential mechanisms preventing the formation of hydric
soil morphologies including low organic-matter inputs, high rates of bioturbation,
and the delivery of high iron-concentrations in soil waters. The application of an
existing hydric soil indicator, A16–coast prairie redox, appears to have some applicability
to the soils we studied. However, further testing and investigation are
required to ensure appropriate management of these endemic natural areas.
Acknowledgments
Thanks to Jerome Langlinais, Charles Love, and Lawrence McGhee (NRCS-Alabama);
Delaney Johnson, Mike Lilly, and Ralph Thornton (NRCS-Mississippi); the National Technical
Committee for Hydric Soils; Al Schotz, Jim Teaford, Gina Todia, and Jim and Louise
Duffy for plant community data; and Mississippi Sandhill Crane Refuge, the Natural Conservancy,
and private landowners for study site access. All photos are credited to Loxley
Soil Survey office staff and Ron Wooten of USACE-Galveston District.
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