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Ecological outcomes and evaluation of success in passively restored southeastern depressional wetlands.

Description: Abstract: Depressional wetlands may be restored passively by disrupting prior drainage to recover original hydrology and relying on natural revegetation. Restored hydrology selects for wetland vegetation; however, depression geomorphology constrains the achievable hydroperiod, and plant communities are influenced by hydroperiod and available species pools. Such constraints can complicate assessments of restoration success. Sixteen drained depressions in South Carolina, USA, were restored experimentally by forest clearing and ditch plugging for potential crediting to a mitigation bank. Depressions were assigned to alternate revegetation methods representing desired targets of herbaceous and wet-forest communities. After five years, restoration progress and revegetation methods were evaluated. Restored hydroperiods differed among wetlands, but all sites developed diverse vegetation of native wetland species. Vegetation traits were influenced by hydroperiod and the effects of early drought, rather than by revegetation method. For mitigation banking, individual wetlands were assessed for improvement from pre-restoration condition and similarity to assigned reference type. Most wetlands met goals to increase hydroperiod, herb-species dominance, and wetland-plant composition. Fewer wetlands achieved equivalence to reference types because some vegetation targets were incompatible with depression hydroperiods and improbable without intensive management. The results illustrated a paradox in judging success when vegetation goals may be unsuited to system constraints.
Date: November 1, 2010
Creator: De Steven, Diane; Sharitz, Rebecca R. & Barton, Christopher, D.
Partner: UNT Libraries Government Documents Department

Vegetation establishment success in restored carolina bay depressions on the Savannah River Site, South Carolina - phase one.

Description: Successful wetlands restoration must re-establish or enhance three parameters: wetland hydrology, hydric soils, and hydrophytic vegetation (Mitsch and Gosselink 2000). On the Savannah River Site, South Carolina, restoration of small Carolina bay depression-wetlands was initiated in FY 2001 to provide wetland acreage for mitigation banking (US DOE 1997). Sixteen small depressions that had historically been drained for agricultural purposes were selected for restoration, and an additional four were initially chosen to serve as non-restored controls. Restoration treatments included plugging the existing ditches to increase water volume retention and wetland hydroperiod and clear-cutting removal of woody vegetation in the interiors. Planned endpoints of the restoration were herbaceous meadow and forested savanna bay interiors, and pine savanna and pine/hardwood forested bay margins (Barton and Singer 2001). To promote forested savanna interiors, saplings of bald cypress and swamp tupelo were planted following removal of the woody species.
Date: May 1, 2004
Creator: Sharitz, Rebecca, A. & Mulhouse, John, M.
Partner: UNT Libraries Government Documents Department

Evaluating hydroperiod response in carolina bay wetlands using soil physicochemical properties.

Description: Abstract Carolina bays are shallow depression wetlands found in the southeastern United States that have been severely altered by human activity. The need to restore these complex and diverse systems is well established, but our limited understanding of wetland hydrologic processes in these systems hinders our ability to assess the effectiveness of bay restoration efforts. Carolina bays exhibit a wide range of moisture regimes from seasonally saturated to semipermanently inundated. Differing physicochemical properties of soils within bay interiors may control bay hydrology. However, previous efforts to establish relationships between soil characteristics and bay hydrology have been inconclusive. An assessment of soil and hydroperiod was initiated in 16 bays designated to be restored and 6 bays that were not restored (reference). Soil morphology was described, and permanent monitoring wells were installed at each site. Multiple regression analysis was used to determine relationships between the soil physicochemical characteristics and the bay hydroperiod for restored and reference bays in both pre- and postrestoration periods. A significant relationship (r2 = 0.75, p = 0.02) between prerestoration hydroperiod and clay content in the argillic horizon (Bt) of the reference bays was observed. This relationship was then used to evaluate hydroperiod change in the restored bays from the postrestoration period. The relationship accurately identified sites that exhibited high prerestoration hydroperiods and did not need hydrologic restoration (n = 4) and effectively showed sites that exhibited substantial increases in hydroperiod due to the restoration activities (n = 7).
Date: December 1, 2008
Creator: Barton, Christopher, D.; Andrews, Danielle, M. & Kolka, Randall, K.
Partner: UNT Libraries Government Documents Department

A comparison of levels of bat flight and foraging activity at 10 meters and 30 meters above drained Carolina bays and reference bays, prior to bay restoration.

Description: A technical report of a monitoring study of bat flight and foraging activity above drained and undrained Carolina bays at the Savannah River Site (SRS), located near Aiken, South Carolina. In order to determine if the vegetational community type or structure of the forest community surrounding the bays affected bat activity levels, bat activity was monitored over 3 drained and 3 undrained reference bays surrounded by pine/mixed hardwood communities and 3 drained and 3 undrained reference bays surrounded by pine monocultures. Bat activity was monitored using time expansion bat detectors. Calls were recorded to Sony Professional tape recorders (Sony WMD3). Detectors positioned at 10 m heights were linked directly to the tape recorders. Time expansion radiomicrophones were used to monitor activity at 30 m heights. The radiomicrophones were attached to 2-m diameter helium balloons and suspended approximately 30 m above the forest floor. Calls detected by the radiomicrophones were transmitted via a FM narrowband frequency to a scanner on the ground.
Date: August 1, 2001
Creator: Menzel, Michael, A.; Ford, W., Mark; Edwards, John, W. & Kilgo, John, C.
Partner: UNT Libraries Government Documents Department

Vegetation of Upper Coastal Plain depression wetlands: Environmental templates and wetland dynamics within a landscape framework.

Description: Reference wetlands play an important role in efforts to protect wetlands and assess wetland condition. Because wetland vegetation integrates the influence of many ecological factors, a useful reference system would identify natural vegetation types and include models relating vegetation to important regional geomorphic, hydrologic, and geochemical properties. Across the U.S. Atlantic Coastal Plain, depression wetlands are a major hydrogeomorphic class with diverse characteristics. For 57 functional depression wetlands in the Upper Coastal Plain of South Carolina, we characterized the principal vegetation types and used a landscape framework to assess how local (wetland-level) factors and regional landscape settings potentially influence vegetation composition and dynamics. Wetland sites were stratified across three Upper Coastal Plain landscape settings that differ in soils, surface geology, topography, and land use. We sampled plant composition, measured relevant local variables, and analyzed historical transitions in vegetative cover types. Cluster analysis identified six vegetation types, ranging from open-water ponds and emergent marshes to closed forests. Significant vegetation-environment relationships suggested environmental ''templates'' for plant community development. Of all local factors examined, wetland hydrologic regime was most strongly correlated with vegetation type, but depression size, soil textural type, and disturbance history were also significant. Because hydrogeologic settings influence wetland features, local factors important to vegetation were partly predictable from landscape setting, and thus wetland types were distributed non-randomly across landscape settings. Analysis of long-term vegetation change indicated relative stability in some wetlands and succession in others. We developed a landscape-contingent model for vegetation dynamics, with hydroperiod and fire as major driving variables. The wetland classification, environmental templates, and dynamics model provide a reference framework to guide conservation priorities and suggest possible outcomes of restoration or management.
Date: March 1, 2004
Creator: De Steven, Diane & Toner, Maureen, M.
Partner: UNT Libraries Government Documents Department

Presence and absence of bats across habitat scales in the Upper Coastal Plain of South Carolina.

Description: Abstract During 2001, we used active acoustical sampling (Anabat II) to survey foraging habitat relationships of bats on the Savannah River Site (SRS) in the upper Coastal Plain of South Carolina. Using an a priori information-theoretic approach, we conducted logistic regression analysis to examine presence of individual bat species relative to a suite of microhabitat, stand, and landscape-level features such as forest structural metrics, forest type, proximity to riparian zones and Carolina bay wetlands, insect abundance, and weather. There was considerable empirical support to suggest that the majority of the activity of bats across most of the 6 species occurred at smaller, stand-level habitat scales that combine measures of habitat clutter (e.g., declining forest canopy cover and basal area), proximity to riparian zones, and insect abundance. Accordingly, we hypothesized that most foraging habitat relationships were more local than landscape across this relatively large area for generalist species of bats. The southeastern myotis (Myotis austroriparius) was the partial exception, as its presence was linked to proximity of Carolina bays (best approximating model) and bottomland hardwood communities (other models with empirical support). Efforts at SRS to promote open longleaf pine (Pinus palustris) and loblolly pine (P. taeda) savanna conditions and to actively restore degraded Carolina bay wetlands will be beneficial to bats. Accordingly, our results should provide managers better insight for crafting guidelines for bat habitat conservation that could be linked to widely accepted land management and environmental restoration practices for the region.
Date: October 1, 2006
Creator: Ford, W.Mark; Menzel, Jennifer M.; Menzel, Michael A.: Edwards, John W. & Kilgo, John C.
Partner: UNT Libraries Government Documents Department

Bat response to carolina bays and wetland restoration in the southeastern U.S. Coastal Plain.

Description: Abstract: Bat activity in the southeastern United States is concentrated over riparian areas and wetland habitats. The restoration and creation of wetlands for mitigation purposes is becoming common in the Southeast. Understanding the effects of these restoration efforts on wetland flora and fauna is thus becoming increasingly important. Because bats (Order: Chiroptera) consist of many species that are of conservation concern and are commonly associated with wetland and riparian habitats in the Southeast (making them a good general indicator for the condition of wetland habitats), we monitored bat activity over restored and reference Carolina bays surrounded by pine savanna (Pinus spp.) or mixed pine-hardwood habitat types at the Savannah River Site in South Carolina. In order to determine how wetland restoration efforts affected the bat community, we monitored bat activity above drained Carolina bays pre- and post-restoration. Our results indicate that bat activity was greater over reference (i.e., undrained) than drained bays prior to the restorative efforts. One year following combined hydrologic and vegetation treatment, however, bat activity was generally greater over restored than reference bays. Bat activity was also greater over both reference and restored bays than in random, forested interior locations. We found significantly more bat activity after restoration than prior to restoration for all but one species in the treatment bays, suggesting that Carolina bay restoration can have almost immediate positive impacts on bat activity.
Date: September 1, 2005
Creator: Menzel, Jennifer M.; Menzel, Michael A.; Kilgo, John C.; Ford, W. Mark & Edwards., John W.
Partner: UNT Libraries Government Documents Department