Virginia journal of science最新文献

{"title":"Effect of Greenhouse Temperature on Tomato Yield and Ripening","authors":"M. Kraemer, Christopher D. Mullins, C. Niedziela","doi":"10.25778/2CWE-QY41","DOIUrl":"https://doi.org/10.25778/2CWE-QY41","url":null,"abstract":"High fuel costs have encouraged producers of greenhouse tomato (Solanum lycopersicum L.) in the mid-Atlantic region to reduce air temperatures during the day. However, effects on fruit ripening and yield are not known, especially under the low light conditions found in off-season production. This 2-yr study compared fruit ripening and yield of tomato under two temperature regimes during the fall season. Two sets of 18 tomato plants, three rows of six, were grown in soilless culture under either a warm or cool temperature regime. Temperatures were similar during night hours but allowed to rise to at least 2124 oC in the cool greenhouse section and 23-26 oC in the warm section, depending on daily solar heating. Mean 24 hour temperature difference between zones was less than 2 oC. Ripe tomato fruit were harvested and weighed 3 times per week for 8 weeks and the remaining un-ripened green tomatoes were weighed at the termination of the experiment to obtain total fruit biomass. The warm zone produced significantly greater weight of ripe tomatoes (23%) than the cool zone. However, total fruit weight (ripe and green), was not significantly different. Thus, a relatively small increase in temperature (2 oC) during the mid-day was associated with a significant increase in fruit ripening but not in total fruit weight. This study showed that greenhouse temperature could be used to better manage fruit production to match weekly market demand without affecting total fruit weight and that consistently maintaining a cool greenhouse would delay tomato ripening and likely increase the potential for plant stress due to high fruit loads remaining on the vines.","PeriodicalId":23516,"journal":{"name":"Virginia journal of science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82156378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Late Holocene Sedimentation and Paleoenvironmental History for the Tidal Marshes of the Potomac and Rappahannock Rivers, Tributaries to Chesapeake Bay","authors":"N. Tibert, J. B. Hubeny, M. Abbott, J. M. Kiker, L. Walker, S. McKenzie","doi":"10.25778/D2GV-6S53","DOIUrl":"https://doi.org/10.25778/D2GV-6S53","url":null,"abstract":"Instrumental tide gauge records indicate that the modern rates of sea-level rise in the Chesapeake Bay more than double the global average of 1.2-1.5 mm yr-1. The primary objective for this study is to establish a relative depositional history for the tidal marshes of the Potomac and Rappahannock Rivers that will help us improve our understanding of processes that influence sedimentation in the proximal tributaries of Chesapeake Bay. Marsh cores were collected from Blandfield Point VA, Tappahannock VA, and Potomac Creek VA. The sedimentary facies include: 1) a lower unit of organic-poor, grey clay with fine sand and silt layers and estuarine foraminifera; and 2) an upper unit of organic-rich clay and peat with abundant brackish to freshwater marsh foraminifera and thecamoebians. AMS 14C dating of bulk marsh sediments yield sedimentation rates at Potomac Creek ranging from 3.04-4.20 mm yr-1 for the past 2500 years. Rates of sedimentation calculated for Blandfield Point indicate 1.37-2.19 mm yr-1 in the basal clays and peat for the past ~3000 years. Foraminiferal census counts indicate a freshening upward trend with a transition from an estuarine Ammobaculites crassus assemblage to a marsh Ammoastuta salsa assemblage with abundant freshwater Thecamoebians. The late Holocene history of sedimentation for the marshes indicates that differential compaction, recent land use practices, and climate change have contributed to the resultant freshening-upward environmental trend and variability in sediment accumulation rates between coring sites. Corresponding author: Neil E. Tibert ntibert@umw.edu 92 VIRGINIA JOURNAL OF SCIENCE INTRODUCTION The Chesapeake Bay watershed comprises numerous tributaries draining from the eastern Appalachian Mountains. The central axis to the Chesapeake has been evaluated in the context of decadal, centennial, and millennial climate changes (Cronin and others 2005, 2010). In the historic Northern Neck region of Virginia, the tidal reaches of the Rappahannock and Potomac Rivers (Fig. 1) have received little detailed study with respect to the nature of the sedimentary record spanning the past several thousand years. Recent estimates for eustatic sea level are estimated to be as high as 1.5-1.88 mm yr (Church and White 2006, Nerem and others 2006) whereas the instrumental tidal -1 FIGURE 1. Location map for the tidal reaches of the Potomac and Rappahannock Rivers. Table1 lists the coordinates and detailed coring information for Sites A-C. Table 2 list coordinates and details for the tide gauge stations (Sites 1-4). Inset shows our location along the eastern Atlantic coast of the USA. Late Holocene Sedimentation 93 records from the Chesapeake Bay indicate rates as high as ~3-4 mm yr (Boon 2012). -1 The disparity between global and regional base level change in the Chesapeake Bay is not well understood and likely reflects the combined effects of allogenic, autogenic, and anthropogenic processes in the region (Cronin 2012). The primar","PeriodicalId":23516,"journal":{"name":"Virginia journal of science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86964481","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploratory Modeling Indicates Red-Backed Salamander Detections are Sensitive to Soil pH at C. F. Phelps Wildlife Management Area, Virginia","authors":"J. D. McGhee, Michael D. Killian","doi":"10.25778/X2ZQ-FF94","DOIUrl":"https://doi.org/10.25778/X2ZQ-FF94","url":null,"abstract":"Red-backed salamanders represent an important component of Virginia ecosystems, but there are few habitat models that can reliably predict the presence/absence of this species. We surveyed the habitats of red-backed salamanders at one site in the Piedmont region of Virginia and collected data on an array of habitat variables with which this species is normally associated. We used logistic regression to develop a model predicting the presence or absence of the species at a given 50m-transect. Our final model incorporated soil organic layer pH variability and mineral layer average pH, and accounted for 30% of the variation in our data. We conclude that soil pH is a limiting determinant of habitat use for this study site, and that it may affect adaptive behaviors for highly acidic soils. INTRODUCTION As researchers address the issues of amphibian decline, there is an increasing need to better understand how salamanders in terrestrial ecosystems interact with their habitat. Greater understanding of the habitat ecology of these species would likely improve our ability to manage and conserve amphibian diversity in local watersheds, thereby reducing the ecosystem damage that would result from the loss of these species (Cushman 2005, Wyman 1990). In the Rappahannock River watershed of Northern Virginia, both Mitchell (1998) and McGhee and Killian (2010) have surveyed amphibian, and specifically, salamander diversity, but little has been done to assess the habitat relationships of commonly detected species. To address this need, we conducted a preliminary study of salamander habitat for a single site in the Rappahannock River drainage at the C. F. Phelps Wildlife Management Area (WMA) concurrent with a species diversity survey and developed a simple habitat model for our most commonly detected terrestrial salamander, Plethodon cinereus Green 1818 (red-backed salamander). Corresponding author: Jay D. McGhee jmcghee@nwmissouri.edu Virginia Journal of Science, Vol. 63, No. 3, 2012 http://digitalcommons.odu.edu/vjs/vol63/iss3 138 VIRGINIA JOURNAL OF SCIENCE The red-backed salamander is common to Virginia forests and the Rappahannock River watershed, and is considered an important component of the local ecosystems in which they occur (Burton and Likens 1975, Davic and Welsh 2004). While several studies have noted particular habitat features associated with this species, such that a hypothetical niche-gestalt can be conceptualized (James 1971), only a few studies have actually developed predictive models of habitat use, primarily to compare the effects of silviculture treatments (Demaynadier and Hunter 1998, Morneault et al. 2004, McKenney et al. 2006). The red-backed salamander occurs in the leaf-litter and well-drained soil underlying deciduous, northern conifer, and mixed deciduous-coniferous forests with numerous cover objects (logs and rocks) and little underbrush (Burger 1935, Petranka 1998, Richmond and Trombulak 2009). This lungless salamander is depend","PeriodicalId":23516,"journal":{"name":"Virginia journal of science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79806757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Distributions and Abundances of Microstegium vimineum along Forest Roadsides at the Grassy Hill Natural Area, Franklin County, Virginia","authors":"Gregory D. Turner","doi":"10.25778/HSXX-MK73","DOIUrl":"https://doi.org/10.25778/HSXX-MK73","url":null,"abstract":"In summer 2005, plots were surveyed along roads passing through forest habitats at the Grassy Hill Natural Area Preserve in Franklin County, Virginia to assess the distributions and abundances of Microstegium vimineum in transects located at increasing distances away from roadsides into forest interiors. Across plots, Microstegium was encountered almost exclusively in roadside transects, where abundances were relatively high. While forest composition and topographic features were similar across plots, percent canopy cover and leaf litter depth were greater in interior compared to roadside transects due to undisturbed tree canopies and ground cover located in interior plot areas. Results imply that Microstegium was restricted to forest roadsides at Grassy Hill at the time of the study, likely due to factors that differ between forest edges and interiors.","PeriodicalId":23516,"journal":{"name":"Virginia journal of science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74749226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advertisement Call and Distribution of the Treefrogs Hyla chrysoscelis and Hyla versicolor in Virginia","authors":"J. Mitchell, Chris A. Pague","doi":"10.25778/1DR5-5Z74","DOIUrl":"https://doi.org/10.25778/1DR5-5Z74","url":null,"abstract":"The gray treefrog complex consists of two sibling species that are indistinguishable morphologically, the diploid Hyla chrysoscelis and the tetraploid Hyla versicolor. Identification is possible in the field only by audio recognition of male advertisement call trill rates (pulses/second). During 1979-1983 we evaluated taped calls of these two species taken from 89 populations from throughout Virginia to map their respective ranges and to evaluate differences in call parameters. Hyla chrysoscelis occurs in the Coastal Plain, eastern and southern Piedmont, and in southwestern Virginia. Hyla versicolor occurs in the Piedmont, Blue Ridge, and Ridge and Valley regions south to Wythe and Tazewell counties. Sympatric sites occur in several locations in the Piedmont and both species are syntopic in several of them. Male trill rates are significantly related to ambient and body temperatures. Rates produced by male H. chrysoscelis (>31/s) are twice as fast as that for H. versicolor (<30/s); they did not overlap in our samples at any temperature. Trill rates and call duration in southwestern Virginia populations of H. chrysoscelis differed significantly from those in eastern populations when adjusted for ambient temperature. Adjusted trill rate and duration in H. chrysoscelis populations in sympatry with H. versicolor were not significantly different from allopatric populations but were for H. versicolor.","PeriodicalId":23516,"journal":{"name":"Virginia journal of science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91102583","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Uptake of Nanoparticles of Cerium Oxide and Yttrium Oxide by Acanthamoeba castellanii (Protozoa) and Daphnia magna (Crustacea)","authors":"J. R. Palmieri, Geneva Gehring, Catherine Minichino, S. F. Elswaifi","doi":"10.25778/J125-7N12","DOIUrl":"https://doi.org/10.25778/J125-7N12","url":null,"abstract":"Currently, nanoparticles are synthesized and used at an unprecedented rate for industrial, medical, and research applications. The use of cerium oxide nanoparticles (CeONP) and yttrium oxide nanoparticles (YtONP) results in their spread as contaminants into the environment. Once in the environment, CeONP and YtONP can be taken up by organisms in the food chain where they may pose a public health risk. In this study we determine whether Acanthamoeba castellanii and Daphnia magna uptake CeONP or YtONP from their environment and thereby play a role in the transmission of the nanoparticles. Using electron microscopy, organisms exposed to the nanoparticles were examined. Our results indicate that the nanoparticles are associated with cell and organelle membranes. These findings have implications for the health risks associated with environmental contamination by CeONP and YtONP. INTRODUCTION In this study we determine whether protists and crustaceans play a role in the transfer of cerium oxide nanoparticles (CeONP) and yttrium oxide nanoparticles (YtONP) from the environment to other organisms within the aquatic food chain. Acanthamoeba castellanii, a common protist, and Daphnia magna, a planktonic crustacean, are important components in many aquatic ecosystems. Because acanthamoebae, such as A. castellanni, are aggressive feeders they consume inorganic and organic compounds from their environment, thereby serving as a link by transferring normally unavailable inorganic components to the food chain (Weekers et al. 1993). D. magna feeds on acanthamoebae and other protists found in lower trophic levels. Because of the high reproductive potential of D. magna, these planktonic crustaceans can substantially alter the structure and functioning of microbial food webs in freshwater ecosystems , such as acidic swamps, freshwater lakes, ponds, rivers and streams (Guisande 1993). D. magna and other aquatic crustaceans have the ability to filter particles of a variety of sizes including nanoparticles (Rosenkranz et al. 2009, Kim et al. 2010, Zhu et al. 2010). The authors hypothesized that CeONP or YtONP in 1 Corresponding author: jpalmieri@vcom.vt.edu Virginia Journal of Science, Vol. 62, No. 1, 2011 https://digitalcommons.odu.edu/vjs/vol62/iss1 4 VIRGINIA JOURNAL OF SCIENCE the natural environment could be taken up by these organisms. Particles engineered at dimensions between 1-100 nm, are referred to as nanoparticles. Currently, nanoparticles are synthesized and used for industrial, medical, and research applications. CeONP are used as diesel fuel additives, in automotive catalytic converters, and are a by-product of many industrial processes, including the polishing of glass and semi-precious stones. CeONP also have potential uses for medical applications acting as an antioxidant (Elswaifi et al. 2009). Yttrium oxide and cerium oxide belong to the rare earth elements. Yttrium oxide nanoparticles (YtONP) are used in the manufacturing of cathode ray tubes for c","PeriodicalId":23516,"journal":{"name":"Virginia journal of science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74632082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Breeding Biology of Oryzomys Palustris, the Marsh Rice Rat, in Eastern Virginia","authors":"R. K. Rose, Erin A. Dreelin","doi":"10.25778/WXHV-ED46","DOIUrl":"https://doi.org/10.25778/WXHV-ED46","url":null,"abstract":"s missing from Volume 62 Number 1 & 2","PeriodicalId":23516,"journal":{"name":"Virginia journal of science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81683430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Functional Feeding Groups, Species Richness, and Spatial Distributions of Fishes in Rocky and Sandy Beach Habitats of St. John, U.S. Virgin Islands","authors":"E. Maurakis, George E. Maurakis, Demetrios E. Maurakis","doi":"10.25778/PM9F-6V82","DOIUrl":"https://doi.org/10.25778/PM9F-6V82","url":null,"abstract":"Objectives were to identify and compare fish species richness, functional feeding group richness and diversity, and delineate distributions of fishes at rocky and sandy beach habitats at St. John, U.S. Virgin Islands. Visual observations using snorkel and mask were made at 3-m intervals seaward from shore during daylight hours. A total of 69 taxa (67 species) representing 33 families of fishes were observed. Total (53) and average fish species richness (32.7) at rocky beach habitats were greater than those (total=43; average=24.3) at sandy beach habitats. Twelve functional feeding groups were identified (diurnal planktivores, excavators/eroders, macroalgae browsers, macrocarnivores, mobile benthic invertivores, general omnivores, strict piscivores, sand invertivores, scrapers, coral/colonial sessile insectivores, territorial algae/detritus, and turf grazers). Total numbers of functional feeding groups (range=10-12) and species (range=29-46) per functional feeding groups at distances greater than 1 m from shore at rocky beach habitats were consistently higher than those (functional feeding group range=8-10; species per functional feeding group=19-30) at sandy beach habitats. Information on the number and composition of functional feeding groups in rocky and sandy beach habitats from this study can serve as a baseline for future investigations as changes in Caribbean habitats continue to occur.","PeriodicalId":23516,"journal":{"name":"Virginia journal of science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82394936","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Garlic as an Alternative Anthelmintic in Sheep","authors":"A. Curry, B. Whitaker","doi":"10.25778/5SFW-ZE15","DOIUrl":"https://doi.org/10.25778/5SFW-ZE15","url":null,"abstract":"An increase in the anthelmintic resistance of parasites in small ruminants and a push towards non-chemical farming has lead researchers to search for alternative forms of anthelmintics. The efficacy of treating sheep by using natural garlic extract with respect to changes in weight, fecal egg counts (FEC), and packed cell volume (PCV) was investigated. Sheep were treated every 4 weeks for 8 weeks with saline (control), Ivermectin, or natural garlic extract and samples were collected weekly to determine FEC and PCV. Sheep were weighed at the time of sample collection to determine weight change. There were no significant differences between the Ivermectin and natural garlic extract treated sheep with respect to weight changes, FEC or PCV. The Ivermectin and natural garlic extract treated sheep had significantly greater (P < 0.05) weight changes and PCV compared to the control. The control sheep had a significantly higher (P < 0.05) FEC compared to the Ivermectin and natural garlic extract treated sheep. Administering natural garlic extract as anthelmintic is a variable alternative to Ivermectin. INTRODUCTION Small ruminant gastrointestinal nematodes potentially reduce production and cause profit loss throughout the sheep industry (Perry and Randolph, 1999). Traditionally, producers have used commercially available anthelmintics (benzimidazoles, imidazothiazoles-tetrahydropyrimidines, and avermectins-milbemycins) to control parasites. However, an increase in the anthelmintic resistance of parasites is currently a serious threat and research is being done to find alternative forms of anthelmintics (Larson, 2006). The societal push towards non-chemical (eco-friendly, green, organic) farming has also hastened the search for viable alternatives to chemical anthelmintics (Waller and Thamsborg, 2004). Haemonchus Contortus, often referred to as the \"barber pole\" worm, punctures the lining of the abomasum, causing blood plasma and protein loss in sheep. Since it is usually the most prevalent nematode parasite in sheep and causes the most destruction, a majority of the research in alternative forms of anthelmintics has been targeting H. Contortus. Copper oxide wire particles administered to sheep have been shown to reduce the number of H. Contortus strongyle eggs shed in lambs (Burke et al., 2004) as well as pregnant ewes (Burke et al., 2005). Developing vaccinations against parasites is becoming a reality with the use of recombinant protein-based vaccines (Knox, 2000), however the economical availability of such vaccines to producers is Corresponding Author: B. D. Whitaker, University of Findlay, 1000 1 North Main Street, Findlay OH, 45840, USA. E-mail: whitaker@findlay.edu Virginia Journal of Science, Vol. 61, No. 1, 2010 http://digitalcommons.odu.edu/vjs/vol61/iss1 4 VIRGINIA JOURNAL OF SCIENCE currently not a possibility. Additional research has shown that feeding forages high in tannin content reduces the fecal egg counts (FEC) and number of worms in go","PeriodicalId":23516,"journal":{"name":"Virginia journal of science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81107462","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Habitat Model for the Detection of Two-lined Salamanders at C. F. Phelps Wildlife Management Area, Fauquier and Culpeper Counties, Virginia","authors":"J. D. McGhee, Michael D. Killian","doi":"10.25778/9s42-h193","DOIUrl":"https://doi.org/10.25778/9s42-h193","url":null,"abstract":"Aquatic salamanders represent an important component of Virginia river watersheds, but despite potential declines, few specifics are known about their habitat preferences. We surveyed the habitats of the northern two-lined salamander and collected data on an array of habitat variables associated with the species. We used a logistic regression analysis to develop a model predicting its presence or absence for a given 50m-transect. Our final model incorporated the variation in stream depth and direction of stream flow and accounted for 25% of the variation in our data. We conclude that stream depth variation is an important feature of salamander habitat ecology, and surmise that direction of flow is of site-specific importance possibly related to stream order. Both features may be behavioral adaptations to avoid fish predation. INTRODUCTION Stream-dwelling salamanders are an important component of aquatic ecosystems. They account for a significant proportion of the biomass of a stream ecosystem, and act as a key trophic link, important as both predators and prey (Spight 1967, Burton and Likens 1975, Rocco and Brooks 2000). Consequently, these salamanders have potential to act as an indicator of stream health (Rocco and Brooks 2000, Barr and Babbitt 2002). This is particularly true for headwater streams were salamanders may act as the dominant vertebrate predator (Davic and Welsh 2004). Accordingly, it would be beneficial to better understand how these species make use of their available habitat. This is especially important in the face of on-going amphibian declines (Alford and Richards 1999). Knowledge of this type may provide better insights into the conservation of these species and their associated ecosystems (Cushman 2005). Previous surveys of stream and terrestrial amphibian diversity have been carried out in the Rappahannock River watershed of northern Virginia; however, more needs to be done to quantify the habitat preferences of important stream species (Mitchell 1998, McGhee and Killian 2010). To begin addressing this need, we conducted a preliminary study of salamander habitat at C.F. Phelps Wildlife Management Area (WMA) located in the Rappahannock River watershed and developed a simple habitat model for the Virginia Journal of Science Volume 61 Number 4 Winter 2010 1 Corresponding author. E-mail: jaymcghee@rmc.edu Virginia Journal of Science, Vol. 61, No. 4, 2010 http://digitalcommons.odu.edu/vjs/vol61/iss4 152 VIRGINIA JOURNAL OF SCIENCE northern two-lined salamander (Eurycea bislineata), a common stream species for the area (McGhee and Killian 2010). Northern two-lined salamanders are common to northern Virginia forest streams within the Rappahannock River watershed (Mitchell and Reay 1999). While they are considered potentially important components of the local ecosystems in which they occur, few studies have developed predictive models of habitat use (Davic and Welsh 2004). They occupy stream margins and seeps, using submerged rock","PeriodicalId":23516,"journal":{"name":"Virginia journal of science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86657475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}