Roanoke River Research Articles

Phylogeography of the northern hogsucker, Hypentelium nigricans (Teleostei: Cypriniformes): genetic evidence for the existence of the ancient Teays River

AbstractAim To assess the roles of dispersal and vicariance in shaping the present distribution and diversity within Hypentelium nigricans, the northern hogsucker (Teleostei: Cypriniformes).Location Eastern United States.Methods Parsimony analyses, Bayesian analyses, pairwise genetic divergence and mismatch plots are used to examine patterns of genetic variation across H. nigricans.Results Species relationships within the genus Hypentelium were consistent with previous hypotheses. However, relationships between haplotypes within H. nigricans revealed two deeply divergent groups, a clade containing haplotypes from the New and Roanoke rivers (Atlantic Slope) plus Interior Highlands and upper Mississippi River and a clade containing haplotypes from the Eastern Highlands, previously glaciated regions of the Ohio and Wabash rivers, and the Amite and Homochitto rivers of south‐western Mississippi.Main conclusions The phylogenetic history of Hypentelium was shaped by old vicariant events associated with erosion of the Blue Ridge and separation of the Mobile and Mississippi river basins. Within H. nigricans two clades existed prior to the Pleistocene; a widespread clade in the pre‐glacial Teays‐Mississippi River system and a clade in Cumberland and Tennessee rivers. Pleistocene events fragmented the Teays‐Mississippi fauna. Following the retreat of the glaciers H. nigricans dispersed northward into previously glaciated regions. These patterns are replicated in other clades of fishes and are consistent with some of the predictions of Mayden's (Systematic Zoology, 37, 329, 1988) pre‐Pleistocene vicariance hypothesis.

From landscapes to waterscapes: A PSE for landuse change analysis

We describe the design and implementation of L2W – a Problem Solving Environment (PSE) for landuse change analysis. L2W organizes and unifies the diverse collection of software typically associated with ecosystem models (hydrological, economic and biological). It provides a web-based interface for potential watershed managers and other users to explore meaningful alternative land development and management scenarios and view their hydrological, ecological, and economic impacts. A prototype implementation for the Upper Roanoke River Watershed in Southwest Virginia, USA is described.

Variability of Atlantic Coast Striped Bass Egg Characteristics

Abstract Eggs of striped bass Morone saxatilis were collected from broodfish at seven hatcheries and one wild population representing nine watersheds from Georgia to Canada to determine the relationship between watershed type and egg characteristics, including density, diameter, oil globule size, surface : volume ratio, and lipid content. These populations represented an inland freshwater lake (Lake Lanier), upland-dominated (high-physical-energy) freshwater rivers (Dan and upper Roanoke (Staunton) rivers), estuarine-influenced (low-physical-energy) coastal rivers (Savannah, Pamunkey, Choptank, and Nanticoke rivers), an upland tidal-bore river (Shubenacadie River), and an upland tidal river (Miramichi River). Water quality parameters varied among hatchery locations. Water hardening of eggs occurred within 2.5 h of fertilization. Egg diameter and relative oil globule size did not differ significantly under ambient hatchery and controlled water quality conditions. However, eggs from different watersheds dif...

Life history strategies of striped bass, Morone saxatilis, populations inferred from otolith microchemistry

Otolith microchemistry was used to investigate genetic, demographic and life history characteristics of striped bass, Morone saxatilis. Striped bass were collected from three river systems along the eastern seaboard: the Neuse River and Roanoke River, North Carolina, USA and the Stewiacke River, Nova Scotia, Canada. The elemental ratios Mn:Ca, Fe:Ca, Br:Ca, Zn:Ca, Cu:Ca and Sr:Ca were measured in otolith nuclei using broad-beam particle induced X-ray emission (PIXE) spectroscopy. Elemental ratios were not significantly different between several Roanoke River genotypes. Two dorsal coloration patterns found in Stewiacke River striped bass indicate the presence of ocean-going (green) and resident (black) contingents, but results of trace elemental analysis showed no differences in elemental signatures of otolith nuclei suggesting that the contingents originate from the same population. Observed Sr:Ca ratios were not stable between Roanoke River year classes; decreased levels of strontium found in 1 year class corresponded with a flooding event. Discriminant analysis using these six elemental ratios correctly identified approximately 88% of the Neuse River, 79% of Stewiacke River, and 47% of the Roanoke River striped bass to the river system from which they were caught during spawning activity. Misclassified individuals might be a result of environmental variability from subhabitats or represent wandering individuals from other populations. The Neuse River population, which is considered to be an endemic riverine population, had no obvious outliers. Results of this study show the increased power of information gathering provided by otolith microchemistry when used in concert with phenotypic and genotypic classification techniques.

Potential for restoration of the Roanoke River population of Atlantic sturgeon

Journal of Applied IchthyologyVolume 18, Issue 4-6 p. 475-480 Potential for restoration of the Roanoke River population of Atlantic sturgeon J. L. Armstrong, J. L. Armstrong North Carolina Division of Marine Fisheries, Morehead City, NC, USA; United States Geological Survey, Biological Resources Division, North Carolina, Cooperative Fish and Wildlife Research Unit, North Carolina State University, Raleigh, NC, USASearch for more papers by this authorJ. E. Hightower, J. E. Hightower North Carolina Division of Marine Fisheries, Morehead City, NC, USA; United States Geological Survey, Biological Resources Division, North Carolina, Cooperative Fish and Wildlife Research Unit, North Carolina State University, Raleigh, NC, USASearch for more papers by this author J. L. Armstrong, J. L. Armstrong North Carolina Division of Marine Fisheries, Morehead City, NC, USA; United States Geological Survey, Biological Resources Division, North Carolina, Cooperative Fish and Wildlife Research Unit, North Carolina State University, Raleigh, NC, USASearch for more papers by this authorJ. E. Hightower, J. E. Hightower North Carolina Division of Marine Fisheries, Morehead City, NC, USA; United States Geological Survey, Biological Resources Division, North Carolina, Cooperative Fish and Wildlife Research Unit, North Carolina State University, Raleigh, NC, USASearch for more papers by this author First published: 17 December 2002 https://doi.org/10.1046/j.1439-0426.2002.00389.xCitations: 20AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume18, Issue4-6December 2002Pages 475-480 RelatedInformation

A synthetic aperture radar–based model to assess historical changes in lowland floodplain hydroperiod

The hydrology of riparian wetlands worldwide has been altered extensively owing to the construction and operation of dams. We developed a model for the Roanoke River floodplain (United States) to simulate flood extent and duration based on a power law correlation between inundation area A, as mapped from synthetic aperture radar (SAR) imagery, and river discharge Q. Model fit was 0.955 for the upper portion of the study area and 0.789 for the tidally influenced lower section. We then compared hydroperiod simulated for predam (1912–1949) and postdam (1965–1995) periods. Topographically wet areas are now flooded longer than before damming, and dry areas are now drier. Similarly, hydrologically wet years experience longer floods, whereas the driest years are drier. Most importantly, spring hydroperiod regimes are now wetter than prior to damming. Our results suggest that the intermediate zone of the hydrologic gradient has been squeezed to either wetter or drier conditions. The model presented represents a simple but effective empirical method to simulate hydroperiod regimes at the landscape scale in large lowland systems where the data necessary to develop more complex physical models are not available.

CONSTRUCTING A PROBLEM SOLVING ENVIRONMENT TOOL FOR HYDROLOGIC ASSESSMENT OF LAND USE CHANGE1

ABSTRACT: This paper describes the integration of a comprehensive hydrological model known as the Hydrological Simulation Program Fortran (HSPF) into a problem solving environment (PSE) for watershed management. The original PSE concept was a structure providing web‐based access to a suite of models, including HSPF and other models of in‐stream hydrodynamics, biological impacts and economic effects, for the watershed‐wide assessment of alternative land use scenarios. The present paper describes only the HSPF integration into the PSE program. Example applications to the 148 square kilometer (57 square mile) Back Creek subwatershed in the upper Roanoke River system (1,479 square kilometers or 571 square miles) in southwest Virginia are used to illustrate important concepts and linkages between land development and hydrological change using hypothetical' what if'scenarios. The features of HSPF and its limitations in this context are discussed. The paper as such is a proof‐of‐concept paper and not a completion report. It is intended to describe the PSE tool building process rather than analysis of the many possible simulation outcomes. However, the dominance of raw imperviousness as a contributor to hydrograph response is apparent in all the PSE simulations described in this paper.

Effects of Fright Bias on Sampling Efficiency of Stream Fish Assemblages

ABSTRACT Relative efficiencies of three different fish sampling techniques (pre-positioned area shockers, single pass electroshocking, and a combined shocking-seining method) with differing potential to induce fright bias were compared in riffle, run and pool habitats in Roanoke River, Virginia. Twenty-three species were captured by the three techniques. Of the three techniques, pre-positioned area shockers had the highest species accumulation rate in each of the three habitats sampled. The single pass electroshocking method had higher species accumulation rates than the combined technique in pools and runs, whereas the performance of the two techniques was similar in riffles. Pre-positioned area shockers also captured a higher proportion of larger, more mobile individuals than the other two techniques. Based on our results, pre-positioned area shockers were the least biased of the three techniques for sampling riverine fish.

Relationships between forest structure and the detection of flood inundation in forested wetlands using C-band SAR

An important practical application of orbital SAR data is the detection of flood inundation beneath forest canopies. C-band microwaves (especially C-VV) are generally considered inferior to longer wavelengths (especially L-band) for mapping flooded forests. Nevertheless C-band data have been shown to exhibit sensitivity to inundation beneath forest canopies. Because of this, the application and interpretation of C-band images requires identification of the forest conditions under which C-band microwaves detect inundation. Images from ERS-1 and RADARSAT representing nearly identical hydrological conditions were used to classify flooded and nonflooded forests for the Roanoke River floodplain, North Carolina, USA. Flooded forests were detected accurately using RADARSAT, and were distinguishable but not mapped accurately using ERS-1. This poses potential problems for the accurate interpretation of C-VV images (i.e. ERS-1/ERS-2) in such environments. To examine this issue, biophysical data from forest plots were used to assess the effect of forest structure on the ability of ERS-1 to detect flooded forests. Basal area (BA) and height to the bottom of the canopy exhibited statistically significant relationships to the detection of inundation using ERS-1, while leaf area index, canopy height, canopy depth, and crown closure were not statistically significant. The results suggest that forest structure and scattering processes at the trunk layer (due to higher BA and open understories with greater heights to the bottom of the canopy) most strongly influence double-bounce scattering of C-VV microwaves from flooded forests.

Estimating forest structure in wetlands using multitemporal SAR

Data from 202 forest plots on the Roanoke River floodplain, North Carolina were used to assess the capabilities of multitemporal radar imagery for estimating biophysical characteristics of forested wetlands. The research was designed to determine the potential for using widely available data from the current set of satellite-borne synthetic aperture radar (SAR) sensors to study forests over broad geographic areas and complex environmental gradients. The SAR data set included 11 Radarsat scenes, 2 ERS-1 images, and 1 JERS-1 scene. Empirical analyses were stratified by flood status such that sites were compared only if they exhibited common flooding characteristics. In general, the results indicate that forest properties are more accurately estimated using data from flooded areas, probably because variations in surface conditions are minimized where there is a continuous surface of standing water. Estimations yielded root mean square errors (RMSEs) for validation data around 10 m 2/ha for basal area (BA), and less than 3 m for canopy height. The r 2 values generally exceeded .65 for BA, with the best predictions coming from sample sites for which both nonflooded and flooded SAR scenes were available. The addition of early spring normalized difference vegetation index (NDVI) values from Landsat Thematic Mapper (Landsat TM) improved model predictions for BA in forests where BA levels were <55 m 2/ha. Further analyses indicated a very limited sensitivity of the individual SAR scenes to differences in forest composition, although soil properties in nonflooded areas exerted a weak but nevertheless important influence on backscatter.

Remote sensing of forested wetlands: application of multitemporal and multispectral satellite imagery to determine plant community composition and structure in southeastern USA

A hierarchical classification of forested wetland communities was developed for the lower Roanoke River floodplain of northeastern North Carolina, USA, through the use of multitemporal and multispectral satellite digital data. Landsat Thematic Mapper (TM) images from different seasons (March–April, May–June, July–August) throughout a single year were used to exploit the phenological variability of forest communities for generating a landcover classification of ecologically important vegetation types within the floodplain. A hierarchical classification scheme was developed that relied upon customized spectral `feature sets' of Landsat TM bands and their transformations to generate the classified images for each level of the forest community classification scheme. The objective was to enhance the discrimination of the community types at subsequent levels of the hierarchical classification scheme through different spectral inputs from the assembled satellite time series in conjunction with detailed floristic information collected though in-situ methods. As such, general landcover classes were iteratively reclassified into more detailed classes at correspondingly `deeper' levels or nodes in the hierarchy. Vegetation classes included 21 forest communities and several other ecologically important classes in the study area. The integration of detailed field data permitted spatially-explicit and highly descriptive definitions of the forest types occurring within the floodplain. Additional field data were used to validate the compositional and structural characteristics of the mapped plant communities described by the classification scheme.

Formulation of Habitat Suitability Models for Stream Fish Guilds: Do the Standard Methods Work?

Habitat suitability index (HSI) models for seven fish guilds in two segments of the upper Roanoke River drainage, Virginia, were formulated for the summer seasons of 1989 and 1990. We considered five habitat variables as potential limiting factors: depth, average and demersal velocities, average substratum size, and percent cover. These physical variables were modeled both separately and as composite HSI indices. Composite models were built from linear regression equations (both simple and multiple) in which the observed guild density in quadrats was regressed against physical microhabitat variables or individual suitability indices (SIs = predicted fish densities). There were five major findings. First, habitat variables were used independently by most fish guilds, as statistical interactions were weak and inconsistent for regression models predicting guild densities from physical variables. That is, fish-microhabitat relations for target habitat variables were typically unaffected by the condition (value) of other habitat variables. Although polynomial (curvilinear) terms were stronger than interaction terms, linear terms accounted for most of the variation in guild densities among quadrats. Second, the predictive power of these complex physical models for guild densities was matched by that of multiplying the SIs for individual microhabitat variables together. Third, this product (joint-suitability-factor) approach was superior to other methods of developing composite HSIs from individual SIs because it was consistently accurate across fish guilds (owing to the lack of strong statistical interactions) and was a simpler regression model (involving only one slope coefficient). Fourth, observed guild densities for each river segment were well correlated with those predicted by the product equation with SI data from the other river segment, thus cross-validating our HSI models in the upper Roanoke River drainage. Fifth, maximum guild densities for habitat variables that were stratified into a few or several categories provided useful indices of the limiting factors for fish guilds because higher densities indicated greater habitat specialization. Across all guilds, depth was consistently the most important factor in habitat selection. In sum, our results suggest that fish-habitat statistical interactions are not strong enough to invalidate the product equation traditionally used by fish researchers to build composite HSI models, at least when SI data are aggregated by habitat use guild.

Relationships between vegetation patterns and hydroperiod on the Roanoke River floodplain, North Carolina

This study quantified relationships between forest composition and flooding gradients on the Roanoke River floodplain, North Carolina. Because flooding is highly variable in time and space, the research was designed to determine the specific hydrological parameters that control woody species abundance on the landscape scale. I specifically tested the importance of spring vs. yearly flood duration, as well as flood duration during hydrologically wet vs. dry years. Field vegetation samples of woody species composition were integrated with spatial data from a Landsat Thematic Mapper (TM) classification and a flood simulation model derived in part from synthetic aperture radar (SAR) imagery. Flood simulations were output and summarized for the periods 1912–1950 (before dams were constructed on the river) and 1965–1996 (after all of the dams were completed). Tenth percentile (dry), median, and 90th percentile (wet) hydroperiod (flood duration) regimes were generated for the spring and year, both pre- and post-dam. Detrended correspondence analysis (DCA) was used to ordinate the plot data, and correlation/regression between ordination axis scores and the flood variables were used to explore the relationships between flooding and species composition. Nineteenth percentile hydroperiod (i.e., wet conditions) correlated most strongly with DCA axis 1 (r>0.9), indicating that inundation during extremely wet years strongly controls species composition on the floodplain. The results were used to quantitatively determine the niche width for both species and mapped vegetation classes in terms of number of days flooded annually and during the spring growth period. The results suggest that spring hydroperiod is an important mechanism that may drive competitive sorting along the flooding gradient, especially during the early years of succession (i.e., pre-dam, which represents the period during which most of the forests sampled were established), and that annual hydroperiod affects the relative dominance of species as the forests mature.

Breeding Bird Abundance in Bottomland Hardwood Forests: Habitat, Edge, and Patch Size Effects

AbstractWe studied breeding bird communities in extensive bottomland hardwood forests along the lower Roanoke River in North Carolina during 1992 and 1993. We documented a rich avian community and recorded exceptionally high densities of two species (Prothonotary Warbler Protonotaria citrea, Acadian Flycatcher Empidonax virescens), as well as modest densities of three species rarely encountered elsewhere in the region (Cerulean Warbler Dendroica cerulea, Swainson's Warbler Limnothlypis swainsonii, American Redstart Setophaga ruticilla). The effects of patch size and edge on bird abundance were small in this forested landscape, but forest type had a large effect. We found half of the species analyzed to differ in abundance between the two primary habitat types, swamp forest and levee forest. In contrast, no species was consistently more abundant at patch interiors than near edges, and only two forest birds were more common in large compared with small patches. Species analyzed included permanent residents, short-distance migrants, Neotropical migrants, and those identified as forest-interior and area-sensitive species in other studies. Our results suggest that the Roanoke River bottomland forests may be functioning effectively as a reserve for a number of bird species.

Habitat Use of Fish Communities in A Virginia Stream System

Fish habitat use during summer was examined at micro- and meso-levels, to determine species associations in the upper Roanoke River watershed, Virginia. Based on multivariate-mesohabitat analysis and examination of mean microhabitat use, seven habitat-use guilds were apparent. These included four rheophilic (fast-riffle, riffle/run, fast-generalist, and shallow-rheophilic) and three limnophilic guilds (pool/run, open-pool, and pool-cover) that were reasonably robust across two river segments and two years. Although simple-hydraulic, bottom-topographic, and turbulence variables all segregated fish habitat-use guilds, turbulence variables were redundant with simple-hydraulic variables, substratum use by limnophilic fishes was related to availability, and only one guild consistently selected high cover levels. At the family level, suckers, darters, and especially minnows were notable for occupying several habitat-use guilds, because of species differences in habitat preferences. Such formulation of guilds can simplify habitat-impact analyses in biodiverse, warmwater streams, via focus on habitat needs of guilds rather than on individual species.

Memorial service honors EMS personnel following “line of duty” deaths

A 9-year-old boy, Julian Stanley Wise, once stood helplessly on the bank of the Roanoke River as 2 canoeists overturned and drowned in front of him. His vow to become a lifesaver was actualized in 1928 when he established the Roanoke Life Saving and First Aid Crew, widely recognized as the nation’s first independent combined life saving and rescue organization. After Mr Wise’s death in 1985, a Foundation bearing his name was formed to honor the work of emergency care providers. This Foundation supports a rescue museum and, since 1993, sponsors a yearly National EMS Memorial Service (NEMSMS) in Roanoke, Va.

BREEDING BIRD ABUNDANCE IN BOTTOMLAND HARDWOOD FORESTS: HABITAT, EDGE, AND PATCH SIZE EFFECTS

Abstract We studied breeding bird communities in extensive bottomland hardwood forests along the lower Roanoke River in North Carolina during 1992 and 1993. We documented a rich avian community and recorded exceptionally high densities of two species (Prothonotary Warbler Protonotaria citrea, Acadian Flycatcher Empidonax virescens), as well as modest densities of three species rarely encountered elsewhere in the region (Cerulean Warbler Dendroica cerulea, Swainson's Warbler Limnothlypis swainsonii, American Redstart Setophaga ruticilla). The effects of patch size and edge on bird abundance were small in this forested landscape, but forest type had a large effect. We found half of the species analyzed to differ in abundance between the two primary habitat types, swamp forest and levee forest. In contrast, no species was consistently more abundant at patch interiors than near edges, and only two forest birds were more common in large compared with small patches. Species analyzed included permanent residents...

Habitat of the Riverweed Darter, Etheostoma podostemone Jordan, and the Decline of Riverweed, Podostemum ceratophyllum, in the Tributaries of the Roanoke River, Virginia

ABSTRACT When the riverweed darter, Etheostoma podostemone Jordan, was described in 1889, riverweed (Podostemum ceratophyllum) was abundant and the riverweed darter was closely associated with it. We compared current conditions of P. ceratophyllum beds to historical accounts, examined the association between the riverweed darter and P. ceratophyllum, determined substrate preferences exhibited by the riverweed darter during and after the spawning season, and compared habitat conditions in the North and South Forks of the Roanoke River. Podostemum ceratophyllum beds were rare in the South Fork of the Roanoke River and nonexistent in the upper North Fork. Causes for the decline of P. ceratophyllum are unknown, though sedimentation and reduced streambed stability are suspected. Median particle size was significantly lower in the North Fork compared to the South Fork. Riverweed darters were encountered in areas with a median particle size of 90mm, median depth-averaged velocity of 0.22m/s, and median depth of 24cm. Comparisons between microhabitat locations where riverweed darters were encountered and randomly chosen microhabitat locations revealed no significant differences; as a result, there is insufficient evidence to conclude that microhabitat selection by riverweed darters is non-random within shallow riffle habitats. However, spawning microhabitats of riverweed darters had higher velocities than randomly chosen microhabitats and higher velocities and depths than summer microhabitats.

Spawning Migration of Telemetered Striped Bass in the Roanoke River, North Carolina

The spring spawning migration is a key period for effective management of anadromous populations of striped bass Morone saxatilis. Information on migratory behavior is needed in order to develop appropriate harvest regulations and to conduct effective surveys while fish are on the spawning grounds. We used ultrasonic telemetry to estimate the timing and duration of the upriver spawning migration for the Roanoke River, North Carolina, population and to evaluate whether a short-term fluctuation in temperature or flow would alter the distribution of telemetered fish on the spawning grounds. Seventy-eight fish implanted with transmitters were released during 1993 and 1994. Twenty-nine telemetered fish migrated upriver in 1994, and 14 telemetered fish entered the river in 1995. Migration of telemetered fish began in mid- to late April when water temperatures in the lower river reached 17–18°C. Males began their spawning migration significantly earlier than females in 1994; the difference was not significant in 1995. The 165-km upriver migration took about a week, as did the downriver migration after the spawning season. In 1994 and 1995 respectively, males remained on the spawning grounds for averages of 22 and 21 d, females for 8 and 11 d. Because of shorter residency times only about half the telemetered females were on the spawning grounds at any one time during the peak of the spawning season. Striped bass remained on the spawning grounds during a short-term temperature decrease of about 4°C (over 5 d) and an increase in flow from about 190 to 390 m3/s (over 1 d).

Catch-and-Release Mortality of Striped Bass in the Roanoke River, North Carolina

Abstract Short-term (72-h) catch-and-release mortality was determined for 153 striped bass Morone saxatilis caught with live bait and artificial lures from spawning grounds in the Roanoke River, North Carolina, during spring 1995. Fish captured by electrofishing were used as the control treatment. Mean adjusted mortality (difference between treatment and control mortality) was 6.4% for striped bass 293–610 mm in total length and was not significantly different between the two fishing methods. Logistic regression analysis showed that mortality was highly dependent on water temperature (P < 0.0005) and hooking location (P < 0.0002), indicating that stress and injury were components of catch-and-release mortality. Mortality of treatment and control fish increased markedly when river temperatures exceeded 21°C. Hooking locations were significantly different (P < 0.0005) between types of terminal gear. Fourteen percent of fish caught on live bait were hooked in sensitive locations (pharynx, esophagus, or gills...