Piedmont Physiographic Province Research Articles

Variation in physicochemical responses to urbanization in streams between two Mid-Atlantic physiographic regions

Urban development substantially alters the physicochemistry of streams, resulting in biodiversity and ecosystem function loss. However, interregional comparisons of physicochemical impact in urban streams suggest that geoclimatic heterogeneity may influence the extent of degradation. In the Mid-Atlantic United States, the adjacent Coastal Plain and Piedmont physiographic provinces possess distinctly different hydrogeomorphic properties that may influence how stream ecosystems respond to urbanization. Recent bioassessments have demonstrated that biotic sensitivity to urbanization is relatively acute in the Piedmont, suggesting that physicochemical change as a consequence of urbanization may be greater in that province. We compared hydrologic, chemical, and thermal characteristics of Mid-Atlantic Coastal Plain and Piedmont first- through fifth-order streams along gradients of impervious surface cover (ISC) at multiple spatial scales. Linear models were applied to test if conditions in rural streams and the degree of impact from ISC varied between provinces. Mean and maximum summer temperatures in Piedmont streams increased more per unit of ISC than in the Coastal Plain. Contrary to expectations, however, variables that quantified high-flow event frequency, magnitude and duration, exhibited significantly greater impact along the ISC gradient in the Coastal Plain. Most chemical changes associated with increasing ISC were similar in the two provinces, although the interregional chemical composition of rural streams differed substantially for most parameters. Our findings demonstrate consistent interregional heterogeneity in stream ecosystem responses to urbanization. Landscape-scale management decisions with stream ecosystem conservation, mitigation, or restoration as a goal must therefore carefully consider the geoclimatic context in order to maximize effectiveness.

Oxidation−Reduction Transformations of Chromium in Aerobic Soils and the Role of Electron-Shuttling Quinones

Oxidation of Cr(III) and reduction of Cr(VI) can occur simultaneously in aerobic soils, but the mechanisms involved are not well-understood, especially how electron shuttling by redox-active organic acids is involved. A and B soil horizons from three topohydrosequences from the Coastal Plain and Piedmont physiographic provinces of Maryland were chosen to investigate oxidation-reduction transformations of Cr under field moist conditions. Reduction of added Cr(VI) to Cr(III) was observed in all 18 samples, and 11 demonstrated enhanced reduction with added anthraquinone-2,6-disulfonate (AQDS) acting as an electron shuttle in 24 h quick tests under aerobic conditions. Oxidation of Cr(III) to Cr(VI) was observed in 12 samples, with 7 demonstrating diminished oxidation with AQDS added. Cr(VI) was undetectable after 11 d of incubation when lactic acid was added as a reductant for Cr(VI) to the Watchung soil A horizon. This reduction occurred in the presence of AQDS and a high salt background to suppress microbial growth, suggesting abiotic reduction was the dominant pathway. The results of this study demonstrate that in field-moist, aerobic soils, the electron shuttle, AQDS, enhanced Cr(VI) reduction and inhibited Cr(III) oxidation. This suggests redox-active organic C amendments and electron shuttles can be important in enhancing rates and extent of Cr(VI) reduction, while inhibiting Cr(III) oxidation in the in situ remediation of Cr(VI)-contaminated soils.

Evaluation of riparian forests established by the Conservation Reserve Enhancement Program (CREP) in Virginia

Forested riparian buffer strips are recommended as an agricultural best management practice for protection of water quality and for wildlife habitat. Since the 1990s, federal and state conservation agencies in Virginia have been involved in establishment of riparian buffers under the auspices of programs, such as the Conservation Reserve Enhancement Program (CREP). Riparian buffers established by the CREP program are considered to be beneficial towards the protection of water quality. However, the benefit is based upon assumption that planted trees and shrubs survive and grow. Little evaluation has been done within the state to document the success of the establishment efforts. We evaluated 63 riparian planting sites located in the Coastal Plain, Piedmont, and Ridge and Valley physiographic provinces of Virginia. Overall, the riparian forests in the Coastal Plain and Piedmont were fully stocked due to a combination of planted and natural regeneration. Riparian forests in the Ridge and Valley region were inadequately stocked, and the region has problems with invasive, exotic species. Major recommendations for improving the success of future riparian restoration and establishment efforts are to (1) include the potential for natural regeneration when planning CREP plantings, (2) stop mechanized operations in the riparian buffers that reduce planted and natural regeneration (e.g., mowing and disking), (3) reduce herbivory (particularly cattle) within the riparian buffer, and (4) control invasive exotic species as necessary.

Suspended‐sediment sources in an urban watershed, Northeast Branch Anacostia River, Maryland

AbstractFine sediment sources were characterized by chemical composition in an urban watershed, the Northeast Branch Anacostia River, which drains to the Chesapeake Bay. Concentrations of 63 elements and two radionuclides were measured in possible land‐based sediment sources and suspended sediment collected from the water column at the watershed outlet during storm events. These tracer concentrations were used to determine the relative quantity of suspended sediment contributed by each source. Although this is an urbanized watershed, there was not a distinct urban signature that can be evaluated except for the contributions from road surfaces. We identified the sources of fine sediment by both physiographic province (Piedmont and Coastal Plain) and source locale (streambanks, upland and street residue) by using different sets of elemental tracers. The Piedmont contributed the majority of the fine sediment for seven of the eight measured storms. The streambanks contributed the greatest quantity of fine sediment when evaluated by source locale. Street residue contributed 13% of the total suspended sediment on average and was the source most concentrated in anthropogenically enriched elements. Combining results from the source locale and physiographic province analyses, most fine sediment in the Northeast Branch watershed is derived from streambanks that contain sediment eroded from the Piedmont physiographic province of the watershed. Sediment fingerprinting analyses are most useful when longer term evaluations of sediment erosion and storage are also available from streambank‐erosion measurements, sediment budget and other methods. Copyright © 2010 John Wiley & Sons, Ltd.

Saturation and Temperature Effects on the Development of Reducing Conditions in Soils

Oxidation‐reduction (redox) reactions regulate many chemical processes that occur in soils. Saturation, C availability, microorganisms, and temperature dictate the rate and type of redox reactions that will occur. The measurement of redox potential enables researchers to predict the stability of redox‐sensitive species, such as Fe oxides. We determine the amount of time Mid‐Atlantic Piedmont floodplain soils must be saturated at a given temperature before becoming reduced with respect to ferrihydrite. Three representative floodplains in Maryland and Delaware were selected for this study. Redox potential, pH, temperature, and depth to water table were measured in six profiles over a 2‐yr period. At lower temperatures, longer periods of saturation were required to induce soil reduction with respect to ferrihydrite (p < 0.0001). The soils were reduced with respect to ferrihydrite after the soils were saturated for 2 to 20 d depending on the 14‐d average soil temperature ranging from 1 to 21°C. When the soil temperature was between 1 and 3.9°C, saturation was required for 20 d before the onset of reducing conditions. At 4 to 6.9°C, 11 d of saturation were required, while at 7 to 8.9°C, 7 d of saturation were required. When the soil temperature was above 9°C, reduction occurred after approximately 2 d. This investigation reveals the importance of considering soil temperature when relating length of saturation to reduction, specifically pertaining to floodplain soils in the Mid‐Atlantic Piedmont physiographic province.

Impacts of land disturbance on aquatic ecosystem health: Quantifying the cascade of events

The impacts of land disturbance on streams have been studied extensively, but a quantitative mechanism of stream degradation is still lacking. Small changes in land use result in changes in physical and chemical characteristics in the stream, which significantly alter biotic integrity. The objective of this study was to quantify the mechanisms of aquatic ecosystem degradation in streams impacted by watershed urbanization. By quantifying the development level and the changes in the physical parameters of receiving streams, the effects of land use change can be illustrated in a conceptual model and evaluated using a traditional ecological risk assessment framework. Three 1st-order streams draining catchments undergoing varying stages of land development were examined in the upper Piedmont physiographic province of South Carolina, U.S.A. A disturbance index was developed to quantify the changes in land use on a monthly basis. This normalized disturbance index (NDI) was quantitatively linked to an increase in the percentage of impervious cover, stormwater runoff, storm-event total suspended solid (TSS) concentrations, and the North Carolina biotic index (NCBI). The NDI was inversely related to a decline in habitat, median bed-sediment particle size, and benthic index of biotic integrity (BIBI). Unlike the percentage of impervious cover, the NDI facilitated the development of strategies for multiple scales of regulation. Predictive multivariate regressions were developed for storm-event TSS concentrations, the BIBI, and the NCBI. These regressions can be used to develop improved regulations for the effects of development and can lead to better implementation of best management practices, improved monitoring of land use change, and more sustainable development.

Prediction of daily flow duration curves and streamflow for ungauged catchments using regional flow duration curves

A method is presented to predict flow duration curves (FDCs) and streamflow for ungauged catchments in the Mid-Atlantic Region, USA. Twenty-nine catchments were selected from the Appalachian Plateau, Ridge and Valley, and Piedmont physiographic provinces to develop and test the proposed method. Using a step-wise multiple regression analysis, the dominant landscape and climate descriptors were identified and regional FDC models were developed for each province. Predictive performance of the proposed method was estimated using data from three evaluation sites that were not included in parameter estimation for the regional FDC models. The results of this study show that climate and geomorphological descriptors strongly influence the hydrology of the Appalachian Plateau and some Ridge and Valley catchments, whereas soil and geomorphological descriptors strongly influence the hydrology of the Piedmont and some Ridge and Valley catchments. Streamflow values calculated by the drainage area ratio method and those reconstructed by the FDC method were compared with the observed streamflow values. The results indicate that the FDC-based method shows great promise for predicting streamflow in ungauged basins.

Long-term average mineral weathering rates from watershed geochemical mass balance methods: Using mineral modal abundances to solve more equations in more unknowns

The number of phases for which weathering rates can be determined by watershed geochemical mass balance is limited by the number of equations that can be constructed from elemental flux losses from the watershed and mineral stoichiometries. Mass balance studies of watershed weathering rates routinely use the flux losses of the six major cations SiO 2, Al, Na, K, Mg, and Ca. Analyses of these species in water are common, but following matrix algebraic methods limits the number of weathering rates that can be calculated to six. For the Brubaker Run watershed located in the northern Piedmont Physiographic Province of Pennsylvania (USA), long-term (10 3–10 6 year) watershed chemical flux losses have been determined using 10Be-derived total denudation rates and zirconium-normalized total chemical concentrations from bedrock and soils. Chemical flux losses calculated from solid-phase data have three advantages: They (1) Permit generation of a relatively large number of equations because both major and trace analyses are included; (2) eliminate the need for many years of regular (e.g., weekly) sampling and chemical analyses of stream water and atmospheric precipitation, and measurement of hydrologic parameters (i.e., precipitation, stream discharge, etc.); and (3) long-term weathering rate calculations need not address biomass. For Brubaker Run, eight minerals are involved in weathering; the five primary minerals are REE-rich epidote, ankerite, almandine–spessartine garnet, muscovite, chlorite, and the three secondary products are weathered muscovite, kaolinite, and gibbsite. The long-term average weathering rates of these minerals were calculated using the six major cations, and two trace elements selected from Rb, Sr, Ba, La, Pr, Nd, Sm, Gd, and Dy. Despite having the eight equations needed, geochemically reasonable weathering rates (e.g., positive primary mineral rates that reflect destruction) could not be achieved regardless of the two trace elements used in the mass balance calculations. For Brubaker Run, this is primarily attributable to the natural heterogeneity of the trace element concentrations within the host mineral grains, with trace element stoichiometries in some minerals varying by as much as an order of magnitude. Because the trace elements are hosted by a relatively small number of minerals, the computed weathering rates of other minerals become very sensitive to small variations in trace cation stoichiometry. REE-rich epidote, garnet, and ankerite within the Brubaker Run watershed together host nearly all of the Ca in the bedrock, and completely dissolve at or near the weathering front. Consequently, approximately all of the Ca in bedrock is lost from the regolith. In bedrock the mole-percentages of Ca hosted by REE-rich epidote, garnet, and ankerite are 49 mol%, 4 mol%, and 43 mol%, respectively, and are determined by the modal abundance of the mineral in the bedrock and its Ca stoichiometry. The weathering rates of REE-rich epidote, garnet, and ankerite can be determined by distributing to each mineral that fraction of the total watershed Ca flux loss for which it is responsible based on its mole-percent Ca in bedrock. By using a base cation that is completely lost from the regolith, and knowing the mole-percentage of that element in the mineral(s) undergoing weathering, additional equations may be added to the mass balance matrix. We term this technique the “flux distribution method.” The flux distribution method eliminates the need for additional equations established using trace elements. Based on the mineral weathering rates for the Brubaker Run watershed determined using the flux distribution method, the rates at which the weathering front penetrated the bedrock (the “saprolitization” rate) are 4.5 m Myr − 1 and 6.5 m Myr − 1 for chlorite and muscovite, respectively. These measured long-term average saprolitization rates compare very favorably with published theoretical values for the nearby northern Maryland Piedmont which range from 2.2 to 5.3 m Myr − 1 .

A Vascular Flora of Lynch's Woods Park, Newberry County, South Carolina

Lynch's Woods Park (Newberry County, South Carolina) was floristically surveyed between 2002 and 2005. The Park features north-facing slopes, granite outcrops, and several small streams within the Piedmont physiographic province. A total of 528 vascular plant species were documented within the 101.2 ha, including 91 (17%) nonnatives. Three species, Anemone berlandieri, Eurybia mirabilis, and Rhododendron eastmanii were rare species. Analysis of community structure revealed that most of the area was a mixed mesophytic forest, with the upland sites developing toward an oak-hickory forest.

Lichen Checklist from the Liking Lichens Teacher Workshops at the Charlie Elliott Wildlife Center, Georgia, USA

Abstract The lichen flora of the Charlie Elliott Wildlife Center in the Georgia Piedmont was explored during successive Liking Lichens Teacher Workshops in July 2006 and 2007. Habitats surveyed include mesic mixed hardwood forest, Oak-Hickory forest and granitic flatrock. A checklist of 146 species in 64 genera from this workshop is presented. This report represents only the second lichen checklist from Georgia, USA, and is one of the first field-based checklists for the Piedmont physiographic province of eastern North America.

Systematics of dusky salamanders, Desmognathus (Caudata: Plethodontidae), in the mountain and Piedmont regions of Virginia and North Carolina, USA

We analysed mitochondrial (cytochrome b) nucleotide sequences, nuclear allozyme markers, and morphometric characters to investigate species boundaries and phylogenetic relationships among dusky salamanders (Desmognathus) in the southern Blue Ridge and adjacent Piedmont Physiographic Provinces of Virginia and North Carolina. Our results revealed four distinct mitochondrial DNA clades that are also characterized by distinct allozyme markers. One clade consists of sequences derived from populations distributed from New England to south-western Virginia that are referable to Desmognathus fuscus Rafinesque, 1820, although there is considerable sequence and allozyme divergence within this clade. A second clade consists of sequences derived from populations referable to Desmognathus planiceps Newman, 1955, a form that we resurrect from its long synonymy under D. fuscus. Desmognathus planiceps and D. fuscus also differ in mandibular tooth shape. Two other cytochrome b sequences recovered from populations along the Blue Ridge escarpment in southern Virginia are quite divergent from those of the previous two clades, and these populations may represent yet another distinct species. Sequences from a population in the Brushy Mountains in the Piedmont of northern North Carolina are similar to those of Desmognathus carolinensis. Population groupings indicated by allozyme data generally correspond to the cytochrome b clades. Cryptic diversity in Appalachian desmognathan salamanders clearly requires further study. © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 152, 115‐130. ADDITIONAL KEYWORDS: allozymes ‐ cytochrome b ‐ Desmognathus planiceps ‐ mitochondrial DNA ‐ morphometrics ‐ phylogeography ‐ taxonomy.

Mammals of the North-central Piedmont of South Carolina

There is a paucity of data on mammal species richness in the Piedmont physiographic province of the Carolinas, especially in north-central South Carolina. Over the last 12 years, I conducted field surveys, searched the literature, and queried numerous museums and agencies to locate records of mammals from the Piedmont province of South Carolina. I recorded 43 species of mammals, four of which are listed as species of state concern, from six counties in north-central South Carolina. Baseline information on mammal species occurrence is critical to future studies and issues of management and conservation.

Leaf breakdown in streams differing in catchment land use

Summary1. The impact of changes in land use on stream ecosystem function is poorly understood. We studied leaf breakdown, a fundamental process of stream ecosystems, in streams that represent a range of catchment land use in the Piedmont physiographic province of the south‐eastern United States.2. We placed bags of chalk maple (Acer barbatum) leaves in similar‐sized streams in 12 catchments of differing dominant land use: four forested, three agricultural, two suburban and three urban catchments. We measured leaf mass, invertebrate abundance and fungal biomass in leaf bags over time.3. Leaves decayed significantly faster in agricultural (0.0465 day−1) and urban (0.0474 day−1) streams than in suburban (0.0173 day−1) and forested (0.0100 day−1) streams. Additionally, breakdown rates in the agricultural and urban streams were among the fastest reported for deciduous leaves in any stream. Nutrient concentrations in agricultural streams were significantly higher than in any other land‐use type. Fungal biomass associated with leaves was significantly lower in urban streams; while shredder abundance in leaf bags was significantly higher in forested and agricultural streams than in suburban and urban streams. Storm runoff was significantly higher in urban and suburban catchments that had higher impervious surface cover than forested or agricultural catchments.4. We propose that processes accelerating leaf breakdown in agricultural and urban streams were not the same: faster breakdown in agricultural streams was due to increased biological activity as a result of nutrient enrichment, whereas faster breakdown in urban streams was a result of physical fragmentation resulting from higher storm runoff.

ESTIMATING STREAMFLOW AND ASSOCIATED HYDRAULIC GEOMETRY, THE MID‐ATLANTIC REGION, USA1

ABSTRACT: Methods to estimate streamflow and channel hydraulic geometry were developed for unpaged streams in the Mid‐Atlantic Region. Observed mean annual streamflow and associated hydraulic geometry data from 75 gaging stations in the Appalachian Plateau, the Ridge and Valley, and the Piedmont Physiographic Provinces of the Mid‐Atlantic Region were used to develop a set of power functions that relate streamflow to drainage area and hydraulic geometry to streamflow. For all three physiographic provinces, drainage area explained 95 to 98 percent of the variance in mean annual streamflow. Relationships between mean annual streamflow and water surface width and mean flow depth had coefficients of determination that ranged from R2= 0.55 to R2= 0.91, but the coefficient of determination between mean flow velocity and mean annual streamflow was lower (R2= 0.44 to R2= 0.54). The advantages of using the regional regression models to estimate streamflow over a conceptual model or a water balance model are its ease of application and reduced input data needs. The prediction of the regression equations were tested with data collected as part of the U.S. Environmental Protection Agency (USEPA) Environmental Monitoring and Assessment Program (EMAP). In addition, equations to transfer streamflow from gaged to ungaged streams are presented.

Evolution of channel morphology and hydrologic response in an urbanizing drainage basin

AbstractThe Dead Run catchment in Baltimore County, Maryland, has undergone intense urbanization since the late 1950s. Reconstruction of the channel planform from topographic maps dating back to the 1890s and aerial photographs dating back to the 1930s indicates that the channel has remained stable in planform since at least the 1930s. The relative stability of Dead Run contrasts with the alterations in channel morphology reported for other urbanizing streams in the Piedmont physiographic province of the eastern United States. Trend analyses of discharge records in Dead Run show that urban development and stormwater control measures have had significant impacts on the hydrologic response of the catchment. The flood hydraulics of the Dead Run catchment are examined for the event that occurred on 22 June 1972 in association with Hurricane Agnes. A two‐dimensional hydraulic model, TELEMAC‐2D, was used with a finite‐element mesh constructed from a combination of high‐resolution LiDAR topographic data and detailed field survey data to analyse the distribution of boundary shear stress and unit stream power along the channel and floodplain during flooding from Hurricane Agnes. The spatial and temporal distributions of these parameters, relative to channel gradient and channel/valley bottom geometry, provide valuable insights on the stability of the Dean Run channel. The stability of Dead Run's channel planform, in spite of extreme flooding and decades of urban development, is most likely linked to geological controls of channel and floodplain morphology. Copyright © 2006 John Wiley & Sons, Ltd.

Estimating plot-level tree heights with lidar: local filtering with a canopy-height based variable window size

In recent years, the use of airborne lidar technology to measure forest biophysical characteristics has been rapidly increasing. This paper discusses processing algorithms for deriving the terrain model and estimating tree heights by using a multiple return, high–density, small-footprint lidar data set. The lidar data were acquired over deciduous, coniferous, and mixed stands of varying age classes and settings typical of the southeastern US. The specific objectives were: (1) to develop and test algorithms to estimate plot level tree height using lidar data, and (2) to investigate how ground measurements can help in the processing phase of lidar data for tree height assessment. The study area is located in the Piedmont physiographic province of Virginia, USA and includes a portion of the Appomattox-Buckingham State Forest (37°25′N, 78°41′W). Two lidar processing algorithms are discussed—the first based on single tree crown identification using a variable window size for local filtering, and the second based on the height of all laser pulses within the area covered by the ground truth data. Height estimates resulted from processing lidar data with both algorithms were compared to field measurements obtained with a plot design following the USDA Forest Service Forest Inventory and Analysis (FIA) field data layout. Linear regression was used to develop equations relating lidar-estimated parameters with field inventories for each of the FIA plots. As expected, the maximum height on each plot was predicted with the highest accuracy ( R 2 values of 85 and 90%, for the first and the second algorithm, respectively). The variable window size algorithm performed better for predicting heights of dominant and co-dominant trees ( R 2 values 84–85%), with a diameter at breast height (dbh) larger than 12.7 cm (5 in), when compared with the algorithm based on all laser heights ( R 2 values 57–73%). The use of field-based height thresholds when processing lidar data did not bring significant gains in explaining the total variation associated with tree height. The technique of local filtering with a variable window size considers fundamental forest biometrics relationships and overall proved to give better results than the technique of all laser shots.

Combining environmentally dependent and independent analyses of witness tree data in east-central Alabama

We reconstructed pre-European settlement forest composition across 13 000 km2 of east-central Alabama using 43 610 witness trees recorded in the original Public Land Surveys. First, we interpolated the witness tree data to estimate broad-scale vegetation patterns. Next, we conducted species–site analysis on landforms, an approach that was dependent on underlying environmental variables yet better resolved fine-scale vegetation patterns. East-central Alabama was dominated by three community types: oak–hickory across the Piedmont physiographic province and valleys of the Ridge and Valley province, pine – blackjack oak on the Coastal Plain province and ridges of the Ridge and Valley province, and white oak – mixed mesophytic in stream valleys and floodplains. Witness tree concentration (trees/km2) was highly uniform across much of the study area. However, there was an unusually low concentration of witness trees in the southwestern corner of the study area, and an unusually high concentration in stream valleys. Another irregularity was the inability of surveyors to distinguish black oak and red oak. Overall, the interpolations provided an unbiased, yet broad-scale estimate of forest composition, while the species–landform analysis greatly increased resolution of forest cover despite the subjectivity of defining environmental variables a priori.

Groundwater Quality Implications of Bank-Storage in a Crystalline-Rock Setting

Numerical simulation of interaction between a river and adjacent alluvium and saprolite groundwaters in the Piedmont physiographic province of western Georgia, U.S.A. suggests that bank storage in this crystalline-rock setting is mediated by elastic storativity rather than the more commonly assumed piston flow. Hydraulic head responds almost instantly to river stage increase despite relatively low hydraulic conductivity of surficial materials. Modeling suggests that aquifer hydraulic head variation is primarily a pressure response to stream stage change and that very little infiltration of river water into alluvium and saprolite occurs. Most unconfined aquifer bank storage models do not account for elastic effects and will therefore greatly underpredict the rate and magnitude of groundwater hydraulic head change and greatly overpredict surface water infiltration. Results suggest that groundwater adjacent to this and similar streams in crystalline-rock settings is not necessarily threatened by contamination from passing surface-water flood waves, even when a strong hydraulic connection between river and groundwater exists and even in cases where hydraulic gradient reverses and is temporarily directed from the river into its banks. Because this site is typical of many near-stream sites in the Piedmont and other crystalline-rock settings, these results may be widely applicable.

Response of Amphibian and Reptile Populations to Vegetation Maintenance of an Electric Transmission Line Right-Of-Way

A 2-year study of amphibian and reptile populations was conducted on a 500-kV transmission line right-of-way (ROW) of PECO Energy in the Piedmont Physiographic Province, Montgomery County, Pennsylvania, U.S., from June through July 1999, September through October 1999, and March through October 2000. The objectives were to compare the diversity and relative abundance of amphibians and reptiles between the ROW and the adjacent forest, among five treatment units on the ROW, and between wire and borders zones on treatments on the ROW. Eight species were observed during the study, and the two most common species were Jefferson salamanders (Ambystoma jeffersonianum) and redback salamanders (Plethodon tinereus). All eight species were noted on the ROW, but only Jefferson and redback salamanders occurred in the adjacent forest. The number of species ranged from six species in the mowing plus herbicide unit to three each in the stem—foliage spray and foliage spray units. All species were found in the wire zones compared to only five species in the border zones. The ROW contained a greater diversity of amphibian and reptile species than the adjacent forest. Because forest-management practices can have negative impacts on populations of amphibians and reptiles, this study provides valuable information on forest-management practices required for the conservation of amphibians and reptiles.

Genetic Variation across a Contact Zone between Montane and Lowland Forms of the Two-Lined Salamander (Eurycea bislineata) Species Complex: A Test of Species Limits

Abstract Extensive genetic variation has been documented throughout the range of the Two-lined salamander (Eurycea bislineata) species complex; however, a lack of fine-scale studies across putative species boundaries in this group has made it difficult to ascertain the amount of gene exchange that occurs between different genetic groups. We investigated patterns of gene exchange in populations from the Blue Ridge Mountains and adjacent Atlantic Slope, by analyzing allozyme variation along a transect that traverses a hypothesized contact zone between montane and lowland forms of the complex, E. wilderae and E. cirrigera. Geographically concordant transitions in allele frequencies at four allozyme loci indicate that a contact zone between these forms exists in the Savannah River drainage in the Piedmont of South Carolina. Variation in the PEP-B locus exhibits a broad cline that crosses the transition between the Blue Ridge and Piedmont physiographic provinces. A fixed difference at one locus (PK), nearly fi...