Tuesday, June 6, 2017
11:00 - 12:30

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11:00 - 11:15: / 301B OCCURRENCE AND CHARACTERISTICS OF GEOGRAPHICALLY ISOLATED WETLANDS IN THE CAROLINA COASTAL PLAIN: SMALL BUT MIGHTY

6/06/2017  |   11:00 - 11:15   |  301B

OCCURRENCE AND CHARACTERISTICS OF GEOGRAPHICALLY ISOLATED WETLANDS IN THE CAROLINA COASTAL PLAIN: SMALL BUT MIGHTY Geographically isolated wetlands (GIWs) are thought to provide important environmental benefits but their size and extent are poorly understood. This study estimated the extent of IWs in an 8-county portion of the coastal plain of North and South Carolina. Geographical information systems were used to create the sampling frame of a probability sampling design used to select candidate GIW sites along the study area. Rapid field assessments were then conducted to determine map accuracy as well as to develop statistically valid estimates of the number, size, extent, and other characteristics of GIWs in the region. We estimated that there were over 52,000 GIWs in the study area occupying about 12,141 hectares (ha) of land, or about 2% of the total wetland area. GIWs were small but numerous with a mean size of 0.27 ha across the study area. Overall most GIWs in the study area were forested ecosystems of three general types (forested flats [50%], forested ponds [33%], and small pocosins [16%]) that occur in relatively small depressions on the uplifted marine terrace and are estimated to contain about 5 million metric tons of carbon.

Kim Matthews (Primary Presenter/Author), RTI International, kmatthews@rti.org;


Breda Munoz ( Co-Presenter/Co-Author), RTI International, breda@rti.org;


Frank Obusek ( Co-Presenter/Co-Author), Hexagon Geospatial, frank.obusek@geoiterations.com;


John Dorney ( Co-Presenter/Co-Author), Moffat & Nichol, Inc, jdorney@moffattnichol.com;


Dan Tufford ( Co-Presenter/Co-Author), University of South Carolina, dan.tufford@sc.edu;


Robert Truesdale ( Co-Presenter/Co-Author), RTI International, rst@rti.org;


Virginia Baker ( Co-Presenter/Co-Author), North Carolina Division of Water Resources, virginia.baker@ncdenr.gov;


Rick Savage ( Co-Presenter/Co-Author), Carolina Wetlands Association, rick.savage@carolinawetlands.org;


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11:15 - 11:30: / 301B HYDROLOGIC CONNECTIVITY AND WATER QUALITY FUNCTIONS OF GEOGRAPHICALLY ISOLATED WETLANDS IN THE CAROLINA COASTAL PLAIN

6/06/2017  |   11:15 - 11:30   |  301B

HYDROLOGIC CONNECTIVITY AND WATER QUALITY FUNCTIONS OF GEOGRAPHICALLY ISOLATED WETLANDS IN THE CAROLINA COASTAL PLAIN Geographically isolated wetlands (GIWs) are wetlands that may not be protected by the Clean Water Act because they have no surface water connections to the “waters of the United States”. However, they are thought to provide the same benefits as other wetlands. This study investigated representatives of a large population of GIWs across an 8-county area of the North and South Carolina coastal plain to confirm whether they are connected to surface water through groundwater and how they influence the hydrologic and water quality functions of these systems. The study found that GIWs in the study area occur when shallow groundwater intersects depressions in the land surface and rises above the ground long enough to produce hydric soils. The generally coarse sandy soils lead to a strong connection between GIWs and downstream surface water bodies and an almost instant water table response to rainfall events. With respect to water quality, GIWs are a carbon, nutrient, and pollutant sink. Given the soils and hydrogeology of these systems is typical of the southeast coastal plain, these results can be extended across the study area and much of the southeast coastal plain.

Robert Truesdale (Primary Presenter/Author), RTI International, rst@rti.org;


Amy Keyworth ( Co-Presenter/Co-Author), NC DEQ, amy.keyworth@ncdenr;


Dan Tufford ( Co-Presenter/Co-Author), University of South Carolina, dan.tufford@sc.edu;


Virginia Baker ( Co-Presenter/Co-Author), North Carolina Division of Water Resources, virginia.baker@ncdenr.gov;


Rick Bolich ( Co-Presenter/Co-Author), NC Department of Environmental Quality, rick.bolich@ncdenr.gov;


Ross Vander Vorste ( Co-Presenter/Co-Author), Virginia Tech, ross.vandervorste@vt.edu;


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11:30 - 11:45: / 301B INCREASED HYDROLOGIC CONNECTIVITY: HUMAN MODIFICATION OF GIW NETWORKS IN DELMARVA PENINSULA

6/06/2017  |   11:30 - 11:45   |  301B

INCREASED HYDROLOGIC CONNECTIVITY: HUMAN MODIFICATION OF GIW NETWORKS IN DELMARVA PENINSULA Combined approaches are required to fully enumerate GIW connectivity and downstream effects. We used spatial analysis and multiple process-based hydrologic models to explore drivers of Delmarva bay hydrologic connectivity, with particular focus on increased connectivity via pervasive ditching throughout this landscape. Modeling at the wetland scale, simulation results reveal the role of channelization (primarily via ditching) among bays to increase surface outflows, with effects to wetland inundation and downgradient flows. Spatial analysis of wetland storage capacities highlights the clear effect of ditches to decrease storage capacity across the landscape. Comparison of contemporary versus historical (no ditch scenario) storage capacities aggregated at catchment scales further illustrates ditch-mediated hydrologic alteration. Building upon this analysis, we applied a catchment-scale model to simulate implications of reduced storage capacity on downstream flows, with effects evident on peak and baseflow dynamics. Our work elucidates key drivers of GIW connectivity and attendant consequences in Delmarva Peninsula while also providing new tools for application in other GIW-rich landscapes. Views expressed are those of the authors and do not necessarily reflect policies of the US EPA or US FWS.

Daniel McLaughlin (Primary Presenter/Author), Virginia Tech University, Department of Forest Resources and Environmental Conservation, mclaugd@vt.edu;


C. Nathan Jones ( Co-Presenter/Co-Author), Virginia Tech University, Department of Forest Resources and Environmental Conservation, cnjones@vt.edu;


Grey Evenson ( Co-Presenter/Co-Author), Virginia Tech University, Department of Forest Resources and Environmental Conservation, gevenson@vt.edu;


Heather Golden ( Co-Presenter/Co-Author), US Environmental Protection Agency, Office of Research and Development, golden.heather@epa.gov;


Charles Lane ( Co-Presenter/Co-Author), US Environmental Protection Agency, Office of Research and Development, lane.charles@epa.gov;


Laurie Alexander ( Co-Presenter/Co-Author), U.S. EPA, alexander.laurie@epa.gov;


Megan Lang ( Co-Presenter/Co-Author), U.S. FWS, megan_lang@fws.gov;


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11:45 - 12:00: / 301B HYDROLOGY AND TRANSPORT DURING EXTREME EVENTS ON A LOW-GRADIENT FORESTED WETLAND WATERSHED, SOUTHEASTERN ATLANTIC COASTAL PLAIN

6/06/2017  |   11:45 - 12:00   |  301B

HYDROLOGY AND TRANSPORT DURING EXTREME EVENTS ON A LOW-GRADIENT FORESTED WETLAND WATERSHED, SOUTHEASTERN ATLANTIC COASTAL PLAIN In this paper we present information on distribution of depressional wetlands in Forest Service Francis Marion National Forest, South Carolina and results of wetland hydrologic analysis for locations with groundwater wells on a typical 52 km2 watershed, that is comprised of 28% forested and 9% non-forested wetlands. Using data from the watershed, stream discharge and contaminant loads with a focus on two extreme precipitation events (October, 2015 and 2016) with very high discharges, that resulted in ponding/flooding of the landscape, are highlighted. While the depressional forested wetlands have large storage capability to hold stormwater, we hypothesize that there is high potential for hydrological connection of these wetlands with other nearby waterbodies through overflows during and following extreme events, and the frequencies of which will potentially continue to increase as a result of projected climate change and sea level rise. However, the connectivity and cumulative transport effects of such depressional wetlands may depend upon their sizes and locations in the landscape that can potentially be evaluated using available modeling tools. Furthermore, the fate of the freshwater export in estuary downstream of the tidal freshwater transition zone is poorly understood.

Devendra Amatya (Primary Presenter/Author), US Forest Service, Southern Research Station, damatya@fs.fed.us;


Carl Trettin ( Co-Presenter/Co-Author), USDA Forest Service Southern Research Station, ctrettin@fs.fed.us;


Augustine Muwamba ( Co-Presenter/Co-Author), College of Charleston, muwambaa@cofc.edu;


Timothy Callahan ( Co-Presenter/Co-Author), College of Charleston, callahanT@cofc.edu;


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12:00 - 12:15: / 301B EXPLORING ECOLOGICAL CONNECTIVITY AMONG GEOGRAPHICALLY ISOLATED WETLANDS

6/06/2017  |   12:00 - 12:15   |  301B

EXPLORING ECOLOGICAL CONNECTIVITY AMONG GEOGRAPHICALLY ISOLATED WETLANDS Connectivity among geographically isolated wetlands (GIW) occurs in several forms—hydrological, ecological, and biogeochemical—across both spatial and temporal scales. We examined three aspects of ecological connectivity in a multi-wetland system on the Savannah River Site (SRS) on the Upper Coastal Plain of South Carolina, USA. We have monitored the primary wetland, Rainbow Bay (RB), since 1978 for pond-breeding amphibian annual breeding numbers and reproductive success. In addition, we haphazardly censused amphibians at four wetlands within 1 km of RB in at least six years during those 38 years and have collected tissue samples from many other wetlands across the 803-ha SRS. We assessed ecological connectivity as 1) net annual nutrient flux in/out of RB relative to the terrestrial habitat, 2) movement of marked amphibians from RB to peripheral wetlands and vice versa in ecological time, and 3) long-term historical amphibian movements among wetlands as determined with genetic methods. We observed that net nutrient flux—i.e., whether RB was a source of nutrients to the uplands or a sink from the uplands—was related to annual variation in wetland hydroperiod. In the mark-recapture studies, we found that fewer than 10% of surviving adult salamanders leave their natal site and disperse to non-natal wetlands, but nonetheless some individuals disperse at least 1 km. Finally, single nucleotide polymorphism analyses of ambystomatid salamanders show evidence of founder effects within GIW, with limited subsequent migration and significant population structure at spatial scales >1 km. Collectively, our results for amphibians illustrate varied ecological connectivity among GIW over space and time and suggest the need for maintaining a variety of wetland types on the landscape, perhaps in spatial clusters, along with upland habitat connections.

David Scott (Primary Presenter/Author), Savannah River Ecology Laboratory, University of Georgia, scott@srel.uga.edu;


Schyler Nunziata ( Co-Presenter/Co-Author), University of Kentucky, schyler.nunziata@uky.edu;


Krista Capps ( Co-Presenter/Co-Author), University of Georgia, kcapps@uga.edu;


Scott Weir ( Co-Presenter/Co-Author), Queens University of Charlotte, weirs@queens.edu;


Stacey Lance ( Co-Presenter/Co-Author), Savannah River Ecology Lab/University of Georgia, lance@srel.uga.edu;


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12:15 - 12:30: / 301B WETLAND ISOLATION AND EXTENDED AMPHIBIAN NONBREEDING PERIODS IN THE SANDHILLS OF NORTH CAROLINA

6/06/2017  |   12:15 - 12:30   |  301B

WETLAND ISOLATION AND EXTENDED AMPHIBIAN NONBREEDING PERIODS IN THE SANDHILLS OF NORTH CAROLINA Seasonally flooded wetlands provide breeding habitat for approximately 36 species of amphibians in the Southeast. Because these wetlands are patchily distributed across the landscape, amphibian species operate as metapopulations. The metapopulation paradigm predicts that isolated wetlands have greater chances of extended periods of nonbreeding by amphibians, lower species richness, and higher extirpation rates. I obtained an approximately 15-20 year dataset of 6 species of amphibian occurrence at 26 ephemeral wetlands in the Sandhills of North Carolina. I measured several habitat characteristics within and around wetlands and quantified isolation by examining the average distance and number of ephemeral wetlands in the surrounding landscape. My results indicated a significant negative relationship between nonbreeding periods and species richness and the number or distance to neighboring wetlands. Additionally, the number of logs surrounding wetlands was positively related to species richness. The lack of significance of most measured habitat characteristics was probably a consequence of the majority of study wetlands occurring within a relatively well-protected and managed landscape and having little among-site variability. These results suggest that isolated wetlands tend to have lower species richness and can experience extended nonbreeding periods.

Matthew Moskwik (Primary Presenter/Author), The Nature Conservancy, matthew.moskwik@tnc.org;


Jeff Beane ( Co-Presenter/Co-Author), North Carolina Museum of Natural Sciences, jeff.beane@naturalsciences.org;


Nathan Shepard ( Co-Presenter/Co-Author), North Carolina Natural Heritage Program, nathan.shepard@ncdcr.gov;


Brian Ball ( Co-Presenter/Co-Author), Endangered Species Branch, Fort Bragg DPW Environmental Division, brian.s.ball4.civ@mail.mil;


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