1
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Chandler HC, Caruso NM, McLaughlin DL, Jiao Y, Brooks GC, Haas CA. Forecasting the flooding dynamics of flatwoods salamander breeding wetlands under future climate change scenarios. PeerJ 2023; 11:e16050. [PMID: 37744236 PMCID: PMC10516105 DOI: 10.7717/peerj.16050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 08/16/2023] [Indexed: 09/26/2023] Open
Abstract
Ephemeral wetlands are globally important systems that are regulated by regular cycles of wetting and drying, which are primarily controlled by responses to relatively short-term weather events (e.g., precipitation and evapotranspiration). Climate change is predicted to have significant effects on many ephemeral wetland systems and the organisms that depend on them through altered filling or drying dates that impact hydroperiod. To examine the potential effects of climate change on pine flatwoods wetlands in the southeastern United States, we created statistical models describing wetland hydrologic regime using an approximately 8-year history of water level monitoring and a variety of climate data inputs. We then assessed how hydrology may change in the future by projecting models forward (2025-2100) under six future climate scenarios (three climate models each with two emission scenarios). We used the model results to assess future breeding conditions for the imperiled Reticulated Flatwoods Salamander (Ambystoma bishopi), which breeds in many of the study wetlands. We found that models generally fit the data well and had good predictability across both training and testing data. Across all models and climate scenarios, there was substantial variation in the predicted suitability for flatwoods salamander reproduction. However, wetlands with longer hydroperiods tended to have fewer model iterations that predicted at least five consecutive years of reproductive failure (an important metric for population persistence). Understanding potential future risk to flatwoods salamander populations can be used to guide conservation and management actions for this imperiled species.
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Affiliation(s)
- Houston C. Chandler
- Department of Fish and Wildlife Conservation, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, United States of America
- The Orianne Society, Tiger, GA, United States of America
| | - Nicholas M. Caruso
- Department of Fish and Wildlife Conservation, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, United States of America
| | - Daniel L. McLaughlin
- Department of Forest Resources and Environmental Conservation, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, United States of America
| | - Yan Jiao
- Department of Fish and Wildlife Conservation, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, United States of America
| | - George C. Brooks
- Department of Fish and Wildlife Conservation, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, United States of America
| | - Carola A. Haas
- Department of Fish and Wildlife Conservation, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA, United States of America
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2
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Mitchell A, Bukvic A, Shao Y, Irish JL, McLaughlin DL. Toward Collaborative Adaptation: Assessing Impacts of Coastal Flooding at the Watershed Scale. Environ Manage 2023; 71:741-754. [PMID: 36507978 DOI: 10.1007/s00267-022-01759-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 11/24/2022] [Indexed: 05/08/2023]
Abstract
The U.S. Mid-Atlantic coastal region is experiencing higher rates of SLR than the global average, especially in Hampton Roads, Virginia, where this acceleration is primarily driven by land subsidence. The adaptation plans for coastal flooding are generally developed at the municipal level, ignoring the broader spatial implications of flooding outside the individual administrative boundaries. Flood impact assessments at the watershed scale would provide a more holistic perspective on what is needed to synchronize the adaptation efforts between the neighboring administrative units. This paper evaluates flooding impacts from sea level rise (SLR) and storm surge among watersheds in Hampton Roads to identify those most at risk of coastal flooding over different time horizons. It also explores the implications of flooding on the municipalities, the land uses, and land covers throughout this region within the case study watershed. The 2% Annual Exceedance Probability (AEP) storm surge flood hazard data and NOAA's intermediate SLR projections were used to develop flooding scenarios for 2030, 2060, and 2090 and delineate land areas at risk of combined flooding. Findings show that five out of 98 watersheds will substantially increase in inundation, with two intersecting multiple municipalities. They also indicate significant inundation of military, commercial, and industrial land uses and wetland land covers. Flooding will also impact residential land use in urban areas along the Elizabeth River and Hampton city, supporting the need for collaborative adaptation planning on hydrologically influenced spatial scales.
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Affiliation(s)
- Allison Mitchell
- Department of Geography, Virginia Tech, 238 Wallace Hall, 295 West Campus Drive, Blacksburg, VA, 24061, USA
| | - Anamaria Bukvic
- Department of Geography, Center for Coastal Studies, Virginia Tech, 207 Wallace Hall, 295 West Campus Drive, Blacksburg, VA, 24061, USA.
| | - Yang Shao
- Department of Geography, Center for Coastal Studies, Virginia Tech, 295 West Campus Drive, Blacksburg, VA, 24061, USA
| | - Jennifer L Irish
- Civil and Environmental Engineering, Center for Coastal Studies, Virginia Tech, 750 Drillfield Drive, Blacksburg, VA, 24061, USA
| | - Daniel L McLaughlin
- Department of Forest Resources & Environmental Conservation, Virginia Tech, 210-C Cheatham Hall, Blacksburg, VA, 24061, USA
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3
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Pence RA, Cianciolo TR, Drover DR, McLaughlin DL, Soucek DJ, Timpano AJ, Zipper CE, Schoenholtz SH. Comparison of benthic macroinvertebrate assessment methods along a salinity gradient in headwater streams. Environ Monit Assess 2021; 193:765. [PMID: 34731316 DOI: 10.1007/s10661-021-09556-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 10/19/2021] [Indexed: 06/13/2023]
Abstract
Benthic macroinvertebrate community assessments are used commonly to characterize aquatic systems and increasingly for identifying their impairment caused by myriad stressors. Yet sampling and enumeration methods vary, and research is needed to compare their abilities to detect macroinvertebrate community responses to specific water quality variables. A common assessment method, rapid bioassessment, uses subsampling procedures to identify a fixed number of individual organisms regardless of total sample abundance. In contrast, full-enumeration assessments typically allow for expanded community characterization resulting from higher numbers of identified organisms within a collected sample. Here, we compared these two sampling and enumeration methods and their abilities to detect benthic macroinvertebrate response to freshwater salinization, a common stressor of streams worldwide. We applied both methods in headwater streams along a salinity gradient within the coal-mining region of central Appalachia USA. Metrics of taxonomic richness, community composition, and trophic function differed between the methods, yet most metrics exhibiting significant response to SC for full-enumeration samples also did for rapid bioassessment samples. However, full-enumeration yielded taxonomic-based metrics consistently more responsive to the salinization gradient. Full-enumeration assessments may potentially provide more complete characterization of macroinvertebrate communities and their response to increased salinization, whereas the more cost-effective and widely employed rapid bioassessment method can detect community alterations along the full salinity gradient. These findings can inform decisions regarding such tradeoffs for assessments of freshwater salinization in headwater streams and highlight the need for similar research of sampling and enumeration methodology in other aquatic systems and for other stressors.
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Affiliation(s)
| | | | | | - Daniel L McLaughlin
- Department of Forest Resources and Environmental Conservation, Virginia Tech, Blacksburg, VA, USA
| | | | - Anthony J Timpano
- Department of Fish and Conservation, Virginia Tech, Blacksburg, VA, USA
| | - Carl E Zipper
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA, USA
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4
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Cianciolo TR, McLaughlin DL, Zipper CE, Timpano AJ, Soucek DJ, Schoenholtz SH. Impacts to water quality and biota persist in mining-influenced Appalachian streams. Sci Total Environ 2020; 717:137216. [PMID: 32062238 DOI: 10.1016/j.scitotenv.2020.137216] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Revised: 02/06/2020] [Accepted: 02/07/2020] [Indexed: 06/10/2023]
Abstract
Elevated dissolved major ions (salinization) from surface coal mining are a common impact to central Appalachian headwater streams. Salinization is associated with alterations of benthic macroinvertebrate communities, as many organisms are adapted to the naturally dilute streams of the region. These geochemical and biological alterations have been observed in streams decades after mining, but it remains unclear whether and at what rate water quality and aquatic biota recover after mining. To address this issue, we analyzed temporal trends in specific conductance (SC), ion matrix ratios, and benthic macroinvertebrate communities over an eight-year period in 23 headwater streams, including 18 salinized by surface coal mining. We found strong, negative correlations between SC and diversity of benthic macroinvertebrate communities. Temporal trend analysis demonstrated limited recovery of water chemistry to natural background conditions. Five of the 18 mining-influenced streams exhibited declining SC; however, annual rates of decline in these streams ranged from 1.9% to 3.7% of mean annual SC, suggesting long time periods will be required to reach established benchmark values (ca. 25 years) or values observed in our five reference study streams (ca. 40 years). Similarly, there was limited evidence for recovery of macroinvertebrate community metrics, even in the few mining-influenced streams with decreasing SC. These findings indicate that salinization and its biological effects persist, likely for decades, in central Appalachian headwater streams. Our work also highlights the value of long-term monitoring data for assessing recovery potential of salinized freshwaters, as well as the need for improved understanding of water quality and biological recovery processes and time frames.
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Affiliation(s)
- Thomas R Cianciolo
- Virginia Polytechnic Institute and State University, Virginia Water Resources Research Center, Virginia Tech, 310 West Campus Dr, RM 210, Blacksburg, VA 24061, USA.
| | - Daniel L McLaughlin
- Virginia Polytechnic Institute and State University, Virginia Water Resources Research Center, Virginia Tech, 310 West Campus Dr, RM 210, Blacksburg, VA 24061, USA.
| | - Carl E Zipper
- Virginia Polytechnic Institute and State University, School of Plant and Environmental Sciences, Virginia Tech, 185 Ag Quad Ln, RM 416, Blacksburg, VA 24061, USA.
| | - Anthony J Timpano
- Virginia Polytechnic Institute and State University, Virginia Water Resources Research Center, Virginia Tech, 310 West Campus Dr, RM 210, Blacksburg, VA 24061, USA.
| | - David J Soucek
- Illinois Natural History Survey, University of Illinois at Urbana-Champaign, 1816 S. Oak St, Champaign, IL 61820, USA.
| | - Stephen H Schoenholtz
- Virginia Polytechnic Institute and State University, Virginia Water Resources Research Center, Virginia Tech, 310 West Campus Dr, RM 210, Blacksburg, VA 24061, USA.
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5
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Cianciolo TR, McLaughlin DL, Zipper CE, Timpano AJ, Soucek DJ, Whitmore KM, Schoenholtz SH. Selenium Bioaccumulation Across Trophic Levels and Along a Longitudinal Gradient in Headwater Streams. Environ Toxicol Chem 2020; 39:692-704. [PMID: 31900941 DOI: 10.1002/etc.4660] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 09/17/2019] [Accepted: 12/31/2019] [Indexed: 06/10/2023]
Abstract
Toxic effects of selenium (Se) contamination in freshwaters have been well documented. However, study of Se contamination has focused on lentic and larger order lotic systems, whereas headwater streams have received little scrutiny. In central Appalachia, surface coal mining is a common Se source to headwater streams, thus providing a useful system to investigate Se bioaccumulation in headwater food chains and possible longitudinal patterns in Se concentrations. Toward that end, we assessed Se bioaccumulation in 2 reference and 4 mining-influenced headwater streams. At each stream, we sampled ecosystem media, including streamwater, particulate matter (sediment, biofilm, leaf detritus), benthic macroinvertebrates, salamanders, and fish, every 400 m along 1.2- and 1.6-km reaches. We compared media Se concentrations within and among streams and evaluated longitudinal trends in media Se concentrations. Selenium concentrations in sampled media were higher in mining-influenced streams compared with reference streams. We found the highest Se concentrations in benthic macroinvertebrates; however, salamanders and fish bioaccumulated Se to potentially harmful levels in mining-influenced streams. Only one stream demonstrated dilution of streamwater Se with distance downstream, and few longitudinal patterns in Se bioaccumulation occurred along our study reaches. Collectively, our results provide a field-based assessment of Se bioaccumulation in headwater food chains, from streamwater to fish, and highlight the need for future assessments of Se effects in headwater streams and receiving downstream waters. Environ Toxicol Chem 2020;39:692-704. © 2020 SETAC.
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Affiliation(s)
- Thomas R Cianciolo
- Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
| | - Daniel L McLaughlin
- Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
| | - Carl E Zipper
- Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
| | - Anthony J Timpano
- Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
| | - David J Soucek
- Illinois Natural History Survey, University of Illinois at Urbana-Champaign, Champaign, Illinois, USA
| | - Keridwen M Whitmore
- Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
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6
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Jones CN, Ameli A, Neff BP, Evenson GR, McLaughlin DL, Golden HE, Lane CR. Modeling Connectivity of Non-floodplain Wetlands: Insights, Approaches, and Recommendations. J Am Water Resour Assoc 2019; 55:559-577. [PMID: 34316250 PMCID: PMC8312621 DOI: 10.1111/1752-1688.12735] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 01/17/2019] [Indexed: 05/25/2023]
Abstract
Representing hydrologic connectivity of non-floodplain wetlands (NFWs) to downstream waters in process-based models is an emerging challenge relevant to many research, regulatory, and management activities. We review four case studies that utilize process-based models developed to simulate NFW hydrology. Models range from a simple, lumped parameter model to a highly complex, fully distributed model. Across case studies, we highlight appropriate application of each model, emphasizing spatial scale, computational demands, process representation, and model limitations. We end with a synthesis of recommended "best modeling practices" to guide model application. These recommendations include: (1) clearly articulate modeling objectives, and revisit and adjust those objectives regularly; (2) develop a conceptualization of NFW connectivity using qualitative observations, empirical data, and process-based modeling; (3) select a model to represent NFW connectivity by balancing both modeling objectives and available resources; (4) use innovative techniques and data sources to validate and calibrate NFW connectivity simulations; and (5) clearly articulate the limits of the resulting NFW connectivity representation. Our review and synthesis of these case studies highlights modeling approaches that incorporate NFW connectivity, demonstrates tradeoffs in model selection, and ultimately provides actionable guidance for future model application and development.
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Affiliation(s)
| | - Ali Ameli
- University of Maryland, School of Environment and Sustainability
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7
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Jensen CK, McGuire KJ, McLaughlin DL, Scott DT. Quantifying spatiotemporal variation in headwater stream length using flow intermittency sensors. Environ Monit Assess 2019; 191:226. [PMID: 30887248 DOI: 10.1007/s10661-019-7373-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 03/07/2019] [Indexed: 05/27/2023]
Abstract
Scientists and policymakers increasingly recognize that headwater regions contain numerous temporary streams that expand and contract in length, but accurately mapping and modeling dynamic stream networks remain a challenge. Flow intermittency sensors offer a relatively new approach to characterize wet stream length dynamics at high spatial and temporal resolutions. We installed 51 flow intermittency sensors at an average spacing of 40 m along the stream network of a high-relief, headwater catchment (33 ha) in the Valley and Ridge of southwest Virginia. The sensors recorded the presence or absence of water every 15 min for 10 months. Calculations of the wet network proportion from sensor data aligned with those from field measurements, confirming the efficacy of flow intermittency sensors. The fine temporal scale of the sensor data showed hysteresis in wet stream length: the wet network proportion was up to 50% greater on the rising limb of storm events than on the falling limb for dry antecedent conditions, at times with a delay of several hours between the maximum wet proportion and peak runoff at the catchment outlet. Less stream length hysteresis was evident for larger storms with higher event and antecedent precipitation that resulted in peak runoff > 15 mm/day. To assess spatial controls on stream wetting and drying, we performed a correlation analysis between flow duration at the sensor locations and common topographic metrics used in stream network modeling. Topography did not fully explain spatial variation in flow duration along the stream network. However, entrenched valleys had longer periods of flow on the rising limbs of events than unconfined reaches. In addition, large upslope contributing areas corresponded to higher flow duration on falling limbs. Future applications that explore the magnitude and drivers of stream length variability may provide further insights into solute and runoff generation processes in headwater regions.
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Affiliation(s)
- Carrie K Jensen
- Department of Forest Resources and Environmental Conservation (MC 0324), Cheatham Hall, RM 313, Virginia Tech, 310 West Campus Drive, Blacksburg, VA, 24061, USA.
- Virginia Water Resources Research Center (MC 0444), Cheatham Hall, STE 210, Virginia Tech, 310 West Campus Drive, Blacksburg, VA, 24061, USA.
| | - Kevin J McGuire
- Department of Forest Resources and Environmental Conservation (MC 0324), Cheatham Hall, RM 313, Virginia Tech, 310 West Campus Drive, Blacksburg, VA, 24061, USA
- Virginia Water Resources Research Center (MC 0444), Cheatham Hall, STE 210, Virginia Tech, 310 West Campus Drive, Blacksburg, VA, 24061, USA
| | - Daniel L McLaughlin
- Department of Forest Resources and Environmental Conservation (MC 0324), Cheatham Hall, RM 313, Virginia Tech, 310 West Campus Drive, Blacksburg, VA, 24061, USA
- Virginia Water Resources Research Center (MC 0444), Cheatham Hall, STE 210, Virginia Tech, 310 West Campus Drive, Blacksburg, VA, 24061, USA
| | - Durelle T Scott
- Department of Biological Systems Engineering (MC 0303), Seitz Hall, RM 202A, Virginia Tech, 155 Ag Quad Lane, Blacksburg, VA, 24061, USA
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8
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Schulte ML, McLaughlin DL, Wurster FC, Balentine K, Speiran GK, Aust WM, Stewart RD, Varner JM, Jones CN. Linking ecosystem function and hydrologic regime to inform restoration of a forested peatland. J Environ Manage 2019; 233:342-351. [PMID: 30590264 DOI: 10.1016/j.jenvman.2018.12.042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 11/29/2018] [Accepted: 12/15/2018] [Indexed: 06/09/2023]
Abstract
Drainage is a globally common disturbance in forested peatlands that impacts peat soils, forest communities, and associated ecosystem functions, calling for informed hydrologic restoration strategies. The Great Dismal Swamp (GDS), located in Virginia and North Carolina, U.S.A., has been altered since colonial times, particularly by extensive ditch networks installed to lower water levels and facilitate timber harvests. Consequently, peat decomposition rates have accelerated, and red maple has become the dominant tree species, reducing the historical mosaic of bald cypress, Atlantic white-cedar, and pocosin stands. Recent repair and installation of water control structures aim to control drainage and, in doing so, enhance forest community composition and preserve peat depths. To help inform these actions, we established five transects of 15 plots each (75 plots total) along a hydrologic gradient where we measured continuous water levels and ecosystem attributes, including peat depths, microtopography, and forest composition and structure. We found significant differences among transects, with wetter sites having thicker peat, lower red maple importance, greater tree density, and higher overall stand richness. Plot-level analyses comported with these trends, clearly grouping plots by transects (via nonmetric multidimensional scaling) and resulting in significant correlations between specific hydrologic metrics and ecosystem attributes. Our findings highlight hydrologic controls on soil carbon storage, forest structure, and maple dominance, with implications for large-scale hydrologic restoration at GDS and in other degraded forested peatlands more broadly.
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Affiliation(s)
- Morgan L Schulte
- Virginia Tech, Department of Forest Resources and Environmental Conservation, USA
| | - Daniel L McLaughlin
- Virginia Tech, Department of Forest Resources and Environmental Conservation, USA.
| | - Frederic C Wurster
- U.S. Fish and Wildlife Service, Great Dismal Swamp National Wildlife Refuge, USA
| | - Karen Balentine
- U.S. Fish and Wildlife Service, Great Dismal Swamp National Wildlife Refuge, USA
| | - Gary K Speiran
- U.S. Geological Survey, Virginia Water Science Center, USA
| | - W Mike Aust
- Virginia Tech, Department of Forest Resources and Environmental Conservation, USA
| | - Ryan D Stewart
- Virginia Tech, School of Plant and Environmental Sciences, USA
| | - J Morgan Varner
- U.S. Forest Service, Pacific Wildland Fire Sciences Laboratory, USA
| | - C Nathan Jones
- University of Maryland, The National Socio-Environmental Synthesis Center, USA
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9
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Evenson GR, Jones CN, McLaughlin DL, Golden HE, Lane CR, DeVries B, Alexander LC, Lang MW, McCarty GW, Sharifi A. A watershed-scale model for depressional wetland-rich landscapes. J Hydrol X 2018; 1:100002. [PMID: 31448367 PMCID: PMC6707518 DOI: 10.1016/j.hydroa.2018.10.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2023]
Abstract
Wetlands are often dominant features in low relief, depressional landscapes and provide an array of hydrologically driven ecosystem services. However, contemporary models do not adequately represent the role of spatially distributed wetlands in watershed-scale water storage and flows. Such tools are critical to better understand wetland hydrological, biogeochemical, and biological functions and predict management and policy outcomes at varying spatial scales. To develop a new approach for simulating depressional landscapes, we modified the Soil and Water Assessment Tool (SWAT) model to incorporate improved representations of depressional wetland structure and hydrological processes. Specifically, we refined the model to incorporate: (1) water storage capacity and surface flowpaths of individual wetlands and (2) local wetland surface and subsurface exchange. We utilized this model, termed SWAT-DSF (DSF for Depressional Storage and Flows), to simulate the ~289 km2 Greensboro watershed within the Delmarva Peninsula of the US Coastal Plain. Model calibration and verification used both daily streamflow observations and remotely sensed surface water extent data (ca. 2-week temporal resolution), allowing us to assess model performance with respect to both streamflow and watershed inundation patterns. Our findings demonstrate that SWAT-DSF can successfully replicate distributed wetland processes and resultant watershed-scale hydrology. SWAT-DSF provides improved temporal and spatial characterization of watershed-scale water storage and flows in depressional landscapes, providing a new tool to quantify wetland functions at broad spatial scales.
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Affiliation(s)
- Grey R. Evenson
- Department of Food, Agricultural, and Biological Engineering, The Ohio State University, Columbus, OH, USA
| | - C. Nathan Jones
- The National Socio-Environmental Synthesis Center, University of Maryland, Annapolis, MD, USA
| | - Daniel L. McLaughlin
- Department of Forest Resources and Environmental Conservation, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Heather E. Golden
- US Environmental Protection Agency, Office of Research and Development, National Exposure Research Laboratory, Cincinnati, OH, USA
| | - Charles R. Lane
- US Environmental Protection Agency, Office of Research and Development, National Exposure Research Laboratory, Cincinnati, OH, USA
| | - Ben DeVries
- Department of Geographical Sciences, University of Maryland, College Park, MD, USA
| | - Laurie C. Alexander
- US Environmental Protection Agency, Office of Research and Development, Washington, DC, USA
| | - Megan W. Lang
- USFWS National Wetlands Inventory Program, Falls Church, VA, USA
| | - Gregory W. McCarty
- US Department of Agriculture – Agricultural Research Service, Hydrology and Remote Sensing Laboratory, Beltsville, MD, USA
| | - Amirreza Sharifi
- Government of the District of Columbia, Department of Energy and Environment, Water Quality Division, Washington, DC, USA
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10
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Diamond JS, McLaughlin DL, Slesak RA, D'Amato AW, Palik BJ. Forested versus herbaceous wetlands: Can management mitigate ecohydrologic regime shifts from invasive emerald ash borer? J Environ Manage 2018; 222:436-446. [PMID: 29894947 DOI: 10.1016/j.jenvman.2018.05.082] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 05/11/2018] [Accepted: 05/26/2018] [Indexed: 06/08/2023]
Abstract
Wetlands self-organize through reciprocal controls between vegetation and hydrology, but external disturbance may disrupt these feedbacks with consequent changes to ecosystem state. Imminent and widespread emerald ash borer (EAB) infestation throughout North American forested wetlands has raised concern over possible ecosystem state shifts (i.e., wetter, more herbaceous systems) and loss of forest function, calling for informed landscape-scale management strategies. In response, we employed a large-scale manipulative study to assess the ecohydrologic response of black ash wetlands to three alternative EAB management strategies: 1) a do-nothing approach (i.e., simulated EAB infestation via tree girdling), 2) a preemptive, complete harvesting approach (i.e., clearcut), and 3) an overstory replacement approach via group selection. We analyzed six years of daily water table and evapotranspiration (ET) dynamics in six blocks comprising black ash wetlands (controls) and management strategy treatments to quantify potential for hydrologic change and subsequent recovery. In both the do-nothing approach and complete harvesting approach, we found persistent changes in hydrologic regime defined by shallower water tables and lower ET rates coupled with increased herbaceous vegetation growth, indicating ecosystem state shifts driven by vegetation-water table interactions. The do-nothing approach showed the least hydrologic recovery after five years, which we attribute to reduction in overstory transpiration as well as greater shade (via standing dead trees) that reduces open water evaporation and herbaceous layer transpiration compared to complete harvesting. We found no evidence of ecohydrologic disturbance in the overstory replacement approach, highlighting its potential as a management strategy to preserve forested wetland habitat if periodically executed over time before EAB infestation. Although the scale of potential disturbance is daunting, our findings provide a baseline assessment for forest managers to develop preemptive mitigation strategies to address the threat of EAB to ecological functions in black ash wetlands.
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Affiliation(s)
- Jacob S Diamond
- School for Forest Resources and Environmental Conservation, Virginia Polytechnic University, Blacksburg VA, USA.
| | - Daniel L McLaughlin
- School for Forest Resources and Environmental Conservation, Virginia Polytechnic University, Blacksburg VA, USA
| | | | - Anthony W D'Amato
- Rubenstein School of Environment and Natural Resources, University of Vermont, Burlington VT, USA
| | - Brian J Palik
- USDA Forest Service, Northern Research Station, Grand Rapids MN, USA
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11
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Evenson GR, Golden HE, Lane CR, McLaughlin DL, D'Amico E. Depressional wetlands affect watershed hydrological, biogeochemical, and ecological functions. Ecol Appl 2018; 28:953-966. [PMID: 29437239 PMCID: PMC7724629 DOI: 10.1002/eap.1701] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 10/24/2017] [Accepted: 01/08/2018] [Indexed: 05/20/2023]
Abstract
Depressional wetlands of the extensive U.S. and Canadian Prairie Pothole Region afford numerous ecosystem processes that maintain healthy watershed functioning. However, these wetlands have been lost at a prodigious rate over past decades due to drainage for development, climate effects, and other causes. Options for management entities to protect the existing wetlands, and their functions, may focus on conserving wetlands based on spatial location vis-à-vis a floodplain or on size limitations (e.g., permitting smaller wetlands to be destroyed but not larger wetlands). Yet the effects of such management practices and the concomitant loss of depressional wetlands on watershed-scale hydrological, biogeochemical, and ecological functions are largely unknown. Using a hydrological model, we analyzed how different loss scenarios by wetland size and proximal location to the stream network affected watershed storage (i.e., inundation patterns and residence times), connectivity (i.e., streamflow contributing areas), and export (i.e., streamflow) in a large watershed in the Prairie Pothole Region of North Dakota, USA. Depressional wetlands store consequential amounts of precipitation and snowmelt. The loss of smaller depressional wetlands (<3.0 ha) substantially decreased landscape-scale inundation heterogeneity, total inundated area, and hydrological residence times. Larger wetlands act as hydrologic "gatekeepers," preventing surface runoff from reaching the stream network, and their modeled loss had a greater effect on streamflow due to changes in watershed connectivity and storage characteristics of larger wetlands. The wetland management scenario based on stream proximity (i.e., protecting wetlands 30 m and ~450 m from the stream) alone resulted in considerable landscape heterogeneity loss and decreased inundated area and residence times. With more snowmelt and precipitation available for runoff with wetland losses, contributing area increased across all loss scenarios. We additionally found that depressional wetlands attenuated peak flows; the probability of increased downstream flooding from wetland loss was also consistent across all loss scenarios. It is evident from this study that optimizing wetland management for one end goal (e.g., protection of large depressional wetlands for flood attenuation) over another (e.g., protecting of small depressional wetlands for biodiversity) may come at a cost for overall watershed hydrological, biogeochemical, and ecological resilience, functioning, and integrity.
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Affiliation(s)
- Grey R Evenson
- Department of Forest Resources and Environmental Conservation, Virginia Polytechnic Institute and State University, Cheatham Hall, Blacksburg, Virginia, 24061, USA
| | - Heather E Golden
- US Environmental Protection Agency, Office of Research and Development, National Exposure Research Laboratory, Cincinnati, Ohio, 45220, USA
| | - Charles R Lane
- US Environmental Protection Agency, Office of Research and Development, National Exposure Research Laboratory, Cincinnati, Ohio, 45220, USA
| | - Daniel L McLaughlin
- Department of Forest Resources and Environmental Conservation, Virginia Polytechnic Institute and State University, Cheatham Hall, Blacksburg, Virginia, 24061, USA
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Jones CN, Evenson GR, McLaughlin DL, Vanderhoof MK, Lang MW, McCarty GW, Golden HE, Lane CR, Alexander LC. Estimating restorable wetland water storage at landscape scales. Hydrol Process 2018; 32:305-313. [PMID: 29681686 PMCID: PMC5907502 DOI: 10.1002/hyp.11405] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Globally, hydrologic modifications such as ditching and subsurface drainage have significantly reduced wetland water storage capacity (i.e., volume of surface water a wetland can retain) and consequent wetland functions. While wetland area has been well documented across many landscapes and used to guide restoration efforts, few studies have directly quantified the associated wetland storage capacity. Here, we present a novel raster-based approach to quantify both contemporary and potential (i.e., restorable) storage capacities of individual depressional basins across landscapes. We demonstrate the utility of this method by applying it to the Delmarva Peninsula, a region punctuated by both depressional wetlands and drainage ditches. Across the entire peninsula, we estimated that restoration (i.e., plugging ditches) could increase storage capacity by 80%. Focusing on an individual watershed, we found that over 59% of restorable storage capacity occurs within 20 m of the drainage network, and that 93% occurs within 1 m elevation of the drainage network. Our demonstration highlights widespread ditching in this landscape, spatial patterns of both contemporary and potential storage capacities, and clear opportunities for hydrologic restoration. In Delmarva and more broadly, our novel approach can inform targeted landscape-scale conservation and restoration efforts to optimize hydrologically mediated wetland functions.
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Affiliation(s)
- Charles Nathan Jones
- The National Socio-Environmental Synthesis Center, University of Maryland, 1 Park Place, Suite 300, Annapolis, MD 21401, USA
- Department of Forest Resources and Environmental Conservation, Virginia Tech, Cheatham Hall, Rm 313, 310 W Campus Dr, Blacksburg, VA 24061, USA
| | - Grey R. Evenson
- Department of Forest Resources and Environmental Conservation, Virginia Tech, Cheatham Hall, Rm 313, 310 W Campus Dr, Blacksburg, VA 24061, USA
| | - Daniel L. McLaughlin
- Department of Forest Resources and Environmental Conservation, Virginia Tech, Cheatham Hall, Rm 313, 310 W Campus Dr, Blacksburg, VA 24061, USA
| | - Melanie K. Vanderhoof
- U.S. Geological Survey Geosciences and Environmental Change Science Center, P.O. Box 25046, DFC, MS 980, Denver, CO 80225, USA
| | - Megan W. Lang
- USFWS National Wetlands Inventory Program, 5275 Leesburg Pike, Falls Church, VA 22041, USA
| | - Greg W. McCarty
- USDA-ARS Hydrology and Remote Sensing Laboratory, 10300 Baltimore Avenue, BLDG. 007, RM. 104, BARC-WEST, Beltsville, MD 20705, USA
| | - Heather E. Golden
- USEPA Office of Research and Development, National Exposure Research Laboratory, 26 West Martin Luther King Drive, Mail Code: 587, Cincinnati, OH 45268, USA
| | - Charles R. Lane
- USEPA Office of Research and Development, National Exposure Research Laboratory, 26 West Martin Luther King Drive, Mail Code: 587, Cincinnati, OH 45268, USA
| | - Laurie C. Alexander
- USEPA Office of Research and Development, National Center for Environmental Assessment, William Jefferson Clinton Building, 1200 Pennsylvania Avenue, N. W., Mail Code: 8623P, Washington, DC 20460, USA
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Golden HE, Creed IF, Ali G, Basu NB, Neff BP, Rains MC, McLaughlin DL, Alexander LC, Ameli AA, Christensen JR, Evenson GR, Jones CN, Lane CR, Lang M. Integrating geographically isolated wetlands into land management decisions. Front Ecol Environ 2017; 15:319-327. [PMID: 30505246 PMCID: PMC6261316 DOI: 10.1002/fee.1504] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Wetlands across the globe provide extensive ecosystem services. However, many wetlands - especially those surrounded by uplands, often referred to as geographically isolated wetlands (GIWs) - remain poorly protected. Protection and restoration of wetlands frequently requires information on their hydrologic connectivity to other surface waters, and their cumulative watershed-scale effects. The integration of measurements and models can supply this information. However, the types of measurements and models that should be integrated are dependent on management questions and information compatibility. We summarize the importance of GIWs in watersheds and discuss what wetland connectivity means in both science and management contexts. We then describe the latest tools available to quantify GIW connectivity and explore crucial next steps to enhancing and integrating such tools. These advancements will ensure that appropriate tools are used in GIW decision making and maintaining the important ecosystem services that these wetlands support.
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Affiliation(s)
- Heather E Golden
- US Environmental Protection Agency (EPA) Office of Research and Development, National Exposure Research Laboratory, Cincinnati, OH
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| | - Irena F Creed
- Department of Biology, Western University, London, Canada
| | - Genevieve Ali
- Department of Geological Sciences, University of Manitoba, Winnipeg, Canada
| | - Nandita B Basu
- Departments of Earth and Environmental Sciences and Civil and Environmental Engineering, University of Waterloo, Waterloo, Canada
| | - Brian P Neff
- US Geological Survey, National Research Program, Lakewood, CO
| | - Mark C Rains
- School of Geosciences, University of South Florida, Tampa, FL
| | - Daniel L McLaughlin
- Department of Forest Resources and Environmental Conservation, Virginia Tech, Blacksburg, VA
| | | | - Ali A Ameli
- Department of Biology, Western University, London, Canada
| | - Jay R Christensen
- EPA Office of Research and Development, National Exposure Research Laboratory, Las Vegas, NV
| | - Grey R Evenson
- Oak Ridge Institute of Science and Education, National Exposure Research Laboratory, Cincinnati, OH
| | - Charles N Jones
- Department of Forest Resources and Environmental Conservation, Virginia Tech, Blacksburg, VA
| | - Charles R Lane
- US Environmental Protection Agency (EPA) Office of Research and Development, National Exposure Research Laboratory, Cincinnati, OH
| | - Megan Lang
- US Fish and Wildlife Service National Wetland Inventory, Falls Church, VA
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Creed IF, Lane CR, Serran JN, Alexander LC, Basu NB, Calhoun AJK, Christensen JR, Cohen MJ, Craft C, D’Amico E, DeKeyser E, Fowler L, Golden HE, Jawitz JW, Kalla P, Kirkman LK, Lang M, Leibowitz SG, Lewis DB, Marton J, McLaughlin DL, Raanan-Kiperwas H, Rains MC, Rains KC, Smith L. Enhancing protection for vulnerable waters. Nat Geosci 2017; 10:809-815. [PMID: 30079098 PMCID: PMC6071434 DOI: 10.1038/ngeo3041] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 08/08/2017] [Indexed: 05/20/2023]
Abstract
Governments worldwide do not adequately protect their limited freshwater systems and therefore place freshwater functions and attendant ecosystem services at risk. The best available scientific evidence compels enhanced protections for freshwater systems, especially for impermanent streams and wetlands outside of floodplains that are particularly vulnerable to alteration or destruction. New approaches to freshwater sustainability - implemented through scientifically informed adaptive management - are required to protect freshwater systems through periods of changing societal needs. One such approach introduced in the US in 2015 is the Clean Water Rule, which clarified the jurisdictional scope for federally protected waters. However, within hours of its implementation litigants convinced the US Court of Appeals for the Sixth Circuit to stay the rule, and the subsequently elected administration has now placed it under review for potential revision or rescission. Regardless of its outcome at the federal level, policy and management discussions initiated by the propagation of this rare rulemaking event have potential far-reaching implications at all levels of government across the US and worldwide. At this timely juncture, we provide a scientific rationale and three policy options for all levels of government to meaningfully enhance protection of these vulnerable waters. A fourth option, a 'do-nothing' approach, is wholly inconsistent with the well-established scientific evidence of the importance of these vulnerable waters.
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Affiliation(s)
- Irena F. Creed
- Department of Biology, Western University, London, ON N6A 5B7, Canada
| | - Charles R. Lane
- US Environmental Protection Agency (US EPA) Office of Research and Development, National Exposure Research Laboratory, Cincinnati, Ohio 45268, USA
| | | | | | - Nandita B. Basu
- Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Aram J. K. Calhoun
- Department of Wildlife, Fisheries, and Conservation Biology, University of Maine, Orono, Maine 04469, USA
| | - Jay R. Christensen
- US EPA Office of Research and Development, National Exposure Research Laboratory, Las Vegas, Nevada 89119, USA
| | - Matthew J. Cohen
- School of Forest Resources and Conservation, University of Florida, Gainesville, Florida 32611, USA
| | - Christopher Craft
- School of Public and Environmental Affairs, Indiana University, Bloomington, Indiana 47405, USA
| | | | - Edward DeKeyser
- School of Natural Resource Sciences, North Dakota State University, Fargo, North Dakota 58102, USA
| | - Laurie Fowler
- Odum School of Ecology, The University of Georgia, Athens, Georgia 30602, USA
| | - Heather E. Golden
- US EPA Office of Research and Development, National Exposure Research Laboratory, Cincinnati, Ohio 45268, USA
| | - James W. Jawitz
- Soil and Water Science Department, University of Florida, Gainesville, Florida 32611, USA
| | - Peter Kalla
- US EPA Region 4 Laboratory, Athens, Georgia 30605, USA
| | | | - Megan Lang
- US Fish and Wildlife Service, Falls Church, Virginia 22041, USA
| | - Scott G. Leibowitz
- US EPA National Health and Environmental Effects Research Laboratory, Western Ecology Division, Corvallis, Oregon 97333, USA
| | - David B. Lewis
- Department of Integrative Biology, University of South Florida, Tampa, Florida 33620, USA
| | - John Marton
- CDM Smith, Inc., Indianapolis, Indiana 46204, USA
| | - Daniel L. McLaughlin
- Department of Forest Resources and Environmental Conservation, Virginia Tech, Blacksburg, Virginia 24061, USA
| | - Hadas Raanan-Kiperwas
- ORISE Fellow, US EPA Office of Wetlands, Oceans, and Watersheds, Washington, DC 20460, USA
| | - Mark C. Rains
- School of Geosciences, University of South Florida, Tampa, Florida 33620, USA
| | - Kai C. Rains
- School of Geosciences, University of South Florida, Tampa, Florida 33620, USA
| | - Lora Smith
- Joseph W. Jones Ecological Research Center, Newton, Georgia 39870, USA
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Cohen MJ, Creed IF, Alexander L, Basu NB, Calhoun AJK, Craft C, D'Amico E, DeKeyser E, Fowler L, Golden HE, Jawitz JW, Kalla P, Kirkman LK, Lane CR, Lang M, Leibowitz SG, Lewis DB, Marton J, McLaughlin DL, Mushet DM, Raanan-Kiperwas H, Rains MC, Smith L, Walls SC. Do geographically isolated wetlands influence landscape functions? Proc Natl Acad Sci U S A 2016; 113:1978-86. [PMID: 26858425 PMCID: PMC4776504 DOI: 10.1073/pnas.1512650113] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Geographically isolated wetlands (GIWs), those surrounded by uplands, exchange materials, energy, and organisms with other elements in hydrological and habitat networks, contributing to landscape functions, such as flow generation, nutrient and sediment retention, and biodiversity support. GIWs constitute most of the wetlands in many North American landscapes, provide a disproportionately large fraction of wetland edges where many functions are enhanced, and form complexes with other water bodies to create spatial and temporal heterogeneity in the timing, flow paths, and magnitude of network connectivity. These attributes signal a critical role for GIWs in sustaining a portfolio of landscape functions, but legal protections remain weak despite preferential loss from many landscapes. GIWs lack persistent surface water connections, but this condition does not imply the absence of hydrological, biogeochemical, and biological exchanges with nearby and downstream waters. Although hydrological and biogeochemical connectivity is often episodic or slow (e.g., via groundwater), hydrologic continuity and limited evaporative solute enrichment suggest both flow generation and solute and sediment retention. Similarly, whereas biological connectivity usually requires overland dispersal, numerous organisms, including many rare or threatened species, use both GIWs and downstream waters at different times or life stages, suggesting that GIWs are critical elements of landscape habitat mosaics. Indeed, weaker hydrologic connectivity with downstream waters and constrained biological connectivity with other landscape elements are precisely what enhances some GIW functions and enables others. Based on analysis of wetland geography and synthesis of wetland functions, we argue that sustaining landscape functions requires conserving the entire continuum of wetland connectivity, including GIWs.
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Affiliation(s)
- Matthew J Cohen
- School of Forest Resources and Conservation, University of Florida, Gainesville, FL 32611;
| | - Irena F Creed
- Department of Biology, Western University, London, ON, Canada N6A 5B7
| | - Laurie Alexander
- National Center for Environmental Assessment, United States Environmental Protection Agency, Washington, DC 20460
| | - Nandita B Basu
- Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, ON, Canada N2L 3G1
| | - Aram J K Calhoun
- Department of Wildlife, Fisheries, and Conservation Biology, University of Maine, Orono, ME 04469
| | - Christopher Craft
- School of Public Health and Environmental Affairs, Indiana University, Bloomington, IN 47405
| | | | - Edward DeKeyser
- School of Natural Resource Sciences, North Dakota State University, Fargo, ND 58108-6050
| | - Laurie Fowler
- Odum School of Ecology, The University of Georgia, Athens, GA 30602
| | - Heather E Golden
- National Exposure Research Laboratory, United States Environmental Protection Agency, Cincinnati, OH 45268
| | - James W Jawitz
- Soil and Water Science Department, University of Florida, Gainesville, FL 32611
| | - Peter Kalla
- Region 4, United States Environmental Protection Agency, Athens, GA 30605
| | | | - Charles R Lane
- National Exposure Research Laboratory, United States Environmental Protection Agency, Cincinnati, OH 45268
| | - Megan Lang
- Department of Geographical Sciences, University of Maryland, College Park, MD 20742
| | - Scott G Leibowitz
- Western Ecology Division, National Health and Environmental Effects Research Laboratory, United States Environmental Protection Agency, Corvallis, OR 97333
| | - David Bruce Lewis
- Department of Integrative Biology, University of South Florida, Tampa, FL 33620
| | | | - Daniel L McLaughlin
- Department of Forest Resources and Environmental Conservation, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
| | - David M Mushet
- Northern Prairie Wildlife Research Center, United States Geological Survey, Jamestown, ND 58401
| | - Hadas Raanan-Kiperwas
- Office of Wetlands, Oceans, and Watersheds, United States Environmental Protection Agency, Washington, DC 20460
| | - Mark C Rains
- School of Geosciences, University of South Florida, Tampa, FL 3362
| | - Lora Smith
- Joseph W. Jones Ecological Research Center, Newton, GA 39870
| | - Susan C Walls
- Wetland and Aquatic Research Center, United States Geological Survey, Gainesville, FL 32653
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Abstract
Wetlands provide numerous ecosystem services, from habitat provision to pollutant removal, floodwater storage, and microclimate regulation. Delivery of particular services relies on specific ecological functions, and thus to varying degree on wetland ecological condition, commonly quantified as departure from minimally impacted reference sites. Condition assessments are widely adopted as regulatory indicators of ecosystem function, and for some services (e.g., habitat) links between condition and function are often direct. For others, however, links are more tenuous, and using condition alone to enumerate ecosystem value (e.g., for compensatory mitigation) may underestimate important services. Hydrologic function affects many services cited in support of wetland protection both directly (floodwater retention, microclimate regulation) and indirectly (biogeochemical cycling, pollutant removal). We investigated links between condition and hydrologic function to test the hypothesis, embedded in regulatory assessment of wetland value, that condition predicts function. Condition was assessed using rapid and intensive approaches, including Florida's official wetland assessment tool, in 11 isolated forested wetlands in north Florida (USA) spanning a land use intensity gradient. Hydrologic function was assessed using hydrologic regime (mean, variance, and rates of change of water depth), and measurements of groundwater exchange and evapotranspiration (ET). Despite a wide range in condition, no systematic variation in hydrologic regime was observed; indeed reference sites spanned the full range of variation. In contrast, ET was affected by land use, with higher rates in intensive (agriculture and urban) landscapes in response to higher leaf area. ET determines latent heat exchange, which regulates microclimate, a valuable service in urban heat islands. Higher ET also indicates higher productivity and thus carbon cycling. Groundwater exchange regularly reversed flow direction at all sites in response to rainfall. This buffering effect on regional aquifer levels, an underappreciated service of isolated wetlands, was provided regardless of condition. Intensive landscapes may benefit most from the hydrologic services that wetlands provide because that is where certain services (floodwater storage, microclimate regulation) are realized. While the portfolio of wetland services clearly changes with disturbance, our results support a revised approach to wetland valuation that recognizes the services that accrue from sustained or enhanced functions in these "working wetlands."
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Affiliation(s)
- Daniel L McLaughlin
- School of Forest Resources and Conservation, University of Florida, 319 Newins-Ziegler Hall, P.O. Box 110410, Gainesville, Florida 32611-0410, USA.
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Song MO, Fort DJ, McLaughlin DL, Rogers RL, Thomas JH, Buzzard BO, Noll AM, Myers NK. Evaluation of Xenopus tropicalis as an alternative test organism for frog embryo teratogenesis assay--Xenopus (FETAX). Drug Chem Toxicol 2003; 26:177-89. [PMID: 12953658 DOI: 10.1081/dct-120022647] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
As a formal recommendation from an Interagency Coordinating Committee for the Validation of Alternative Methods (ICCVAM) workshop review of the Frog Embryo Teratogenesis Assay--Xenopus (FETAX) developmental toxicity model, the use of Xenopus tropicalis as an alternative test species for this model was evaluated. Three test substances with varying developmental toxicity potentials were evaluated using FETAX modified to accommodate the use of X. tropicalis. Two separate definitive concentration-response tests were performed with isoniazid, methotrexate, and 6-aminonicotinamide. Historical FETAX results with X. laevis were compared to the results from FETAX assays with X. tropicalis. Test with X. tropicalis indicated that each of the compounds possessed teratogenic potential with varying degrees of potency: 6-aminonicotinamide > methotrexate > isoniazid. Based on overt teratogenicity, but not embryo-lethality, results from these studies indicated that these two species responded similarly to the test compounds. Malformation syndromes induced in both species were similar in X. tropicalis and X. laevis. These results suggested that X. tropicalis should be further evaluated as an alternative test organism for the FETAX model.
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Affiliation(s)
- Min Ok Song
- National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
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Lis AW, McLaughlin RK, McLaughlin DL, Daves GD, Anderson WR. 5-Chlorocytosine. Occurrence in salmon sperm deoxyribonucleic acid. J Am Chem Soc 1973; 95:5789-90. [PMID: 4733822 DOI: 10.1021/ja00798a073] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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