The Virginia Coast Reserve LTER
1997-1998 Annual Report
1 August 1998
Highlights of VCR/LTER Research
The Virginia Coast Reserve (VCR) is a dynamic, frequently disturbed landscape with elements that differ in degrees normally associated with biome-level differences. The types of ecosystem changes that normally occur across large distances (continents, biomes) and over long periods of time (e.g. glacial and interglacial periods) happen on decadal time-scales. As a result, ecosystem state changes are frequent. The central research theme of the Virginia Coast Reserve Long-Term Ecological Research project is the understanding of the dynamics of ecosystem state change, both the transitions among ecosystem states and succession within these states. The VCR/LTER project has been able to take advantage of the unusually high rates of shoreline change and sea level rise to achieve new understandings of the dynamics of coastal systems. Some recent research findings include: new theories on how marsh and lagoon systems evolve and operate, the discovery that trends in coastal erosion undergo reversals and that these reversals are roughly synchronous along the entire Atlantic Coast (due to changes in storm climates), a more detailed understanding of successional processes on barrier islands (including microbial influences on shrub succession), whether salt marshes are able to accumulate enough new material to keep up with current rates of sea level rise, and patterns of colonization and extinction for mammals and birds on barrier islands. We have listed specific highlights by LTER core area.
SOUTH PARRAMORE OVERWASH SITE -- Major winter storms in early 1998 (Jan-Feb) caused more than 50 m of shoreline retreat in the vicinity of our long-term overwash monitoring site near the UVa pimple project location. Erosion in 1998 resulted in the total removal of one entire pimple that was instrumented with more approximately 18 wells tracking changes in groundwater elevation and salinity. The storm overwash removed major dunes and dune ridges from this location and produced a low-relief barrier island environment. Ongoing GPS resurveys are being processed to determine the details of the changes. When processed later this summer, these GPS data will be used to provide detailed estimates of the volumetric changes of geomorphic subenvironments in the region. We also will be able to use the 1997 mapping data to track the storm's impact on island hydrology and vegetation. Because we had completed a detailed GPS survey of the site in 1997, along with a vegetative and hydrological survey, we will be able to provide one of the best-detailed assessments of island response to coastal storms ever possible.
GPS SURVEY MAPPING -- Significant effort has been put into assessing the utility of GPS technology in sub-cm scale geomorphic mapping of barrier island environments during the past year. This has been a cooperative effort coordinated by Randy Carlson. The results of the first year indicate that GPS mapping provides a favorable platform for monitoring geomorphic and vegetative changes on barrier islands a scale useful in tracking annual changes and changes due to major storm events.
MYRTLE ISLAND LANDSCAPE CHANGE -- Repeated GPS surveys since 1996 have documented major island-scale geomorphic adjustments along the northern half of Myrtle Island. These changes are measured on the order of 100's of m of shoreline retreat and 100's of square m of destruction of major dune environments. Much of these adjustments began prior to the major storms of early 1998 and must be attributed to changes in geomorphic processes operating at high frequency. Studies are currently underway to determine if these island adjustments are influenced by hydrographic adjustments in adjacent tidal inlets or inlet delta platforms.
NETWORK ANALYSIS OF NITROGEN CYCLING -- It is hard to impossible to measure how nutrients cycle within an ecosystem. The cycling involves many different processes and the ecosystem integrates them all. Nitrogen is a nutrient that has a particularly complex cycle. We have begun to assess how marshes cycle nitrogen as a whole (not just through adding the different parts) by way of network analysis. Network analysis applies different mathematical calculations to box and arrow diagrams of systems. We have made such diagrams of the nitrogen cycles from marshes at Great Sippewissett, Mass.; Sapelo Island, GA; and the VCR. Within each marsh separate analyses were done for 3 zones of the marsh. Patterns can be seen in the ways the marshes process nitrogen. An important controlling feature is the distance from tidal flooding. As sea level rises it can be seen to alter the way the marshes process nitrogen.
NITROGEN CYCLING IN THE BARRIER ISLAND LAGOON SYSTEM -- A study on nitrogen dynamics in Hog Island Bay was initiated. Our main objective is determining the extent to which biological transformations in the lagoon act to remove or retard reactive nitrogen during transport across the land-sea margin. We are particularly interested in the role of benthic autotrophs – microalgae and macroalgae – in these biological transformations. Studies performed during October 1997 and May 1998 suggest that the Hog Island Bay is net autotrophic and a sink for dissolved inorganic nitrogen. However, during July when macroalgae undergo a period of mortality and decomposition, the lagoon becomes net heterotrophic and sediments are a source of nitrogen, especially dissolved organic nitrogen, to the lagoon.
ROLE OF PRECIPITATION IN HIGH MARSH FLOODING --Coastal fringe salt marshes are often divided into two hydrologic zones based largely on vegetation and flooding frequency. Low marsh vegetation is dominated by Spartina alterniflora, depicted as a regularly flooded zone, and a high marsh of mixed species, depicted as an irregularly flooded zone. One interpretation is that tides are a dominant source of flooding in the high marsh, albeit irregular. From a 6-year record of a mainland marsh at the VCR/LTER (upper Phillips Creek), we found that flooding in high marsh zones is due largely to precipitation, and lasts for months without drydown. Depressional storage of high marsh zones is effective in storing water, which contributes to the long hydroperiod and saturation to the surface.
ORGANIC MATTER ACCUMULATION IN MARSH SEDIMENTS -- Long-term measures of organic matter accumulation continue to show significantly greater rates in the high marsh as compared to creekbank regions. These rates are correlated with differences in root production and with sediment physiochemical differences between high and low marsh. To determine the contribution of organic matter accumulation to sediment surface accretion, a 10-yr experiment has been initiated in conjunction with Don Cahoon (National Wetlands Research Center) by VCR PIs Linda Blum, Mark Brinson, and Bob Christian. Sediment erosion tables and feldspar marker layers are being used to measure sediment surface elevation and sediment deposition in the high marsh, low marsh, and mid marsh, as well as along an actively developing tidal creek. Organic matter accretion is being measured as accumulation of organic materials in litter bags. A similar series of measurements is being initiated at Merritt Island National Wildlife Refuge in impounded wetlands.
SEDIMENT DEPOSITION -- The physical processes that control mineral sediment deposition on a mesotidal salt marsh surface at the VCR have been through a series of measurements of sediment concentration, flow velocity, water surface elevation and local rates of deposition on the marsh surface under tidal conditions ranging from tides barely flooding the marsh surface to spring tides and storm surges. Flow velocities on the marsh surface are low (< 1cm/s) during all tidal conditions measured. Sediment concentrations at the edge of the marsh increase with increased tidal amplitude, whereas in the marsh interior sediment concentration remained low regardless of tidal amplitude. The concentration gradient between creek bank and marsh interior indicates that more sediment is deposited on the creek bank as tidal amplitude increases. Correlation of high sediment transport events with meteorological conditions indicate that all high transport events are associated with strong northeasterly winds. Based on these measurements, it is estimated that 27% of sediment deposited on this mesotidal marsh surface is contributed by storms; the rest is deposited during normal high spring tides.
MICROBIAL SYMBIONTS -- Coastal environments are harsh and physical factors (e.g. salinity, flooding, and sand deposition) strongly influence the distribution of plants, but biotic interactions are also very important. Mutualistic interactions with microbial symbionts to fix nitrogen and provide other nutrients enhances the establishment of shrubs. In fact, regardless of how optimal the physical environment is, wax myrtle, Myrica cerifera, will not survive unless the bacterium, Frankia, is in the soil. Frankia infects the root to form nodules that enable nitrogen fixation.
MICROBIAL COMMUNITIES IN HOG ISLAND LAGOON -- The spatial and temporal response of the bacterial communities have been examined for the past two years along the VCR’s water quality monitoring transect from tidal marsh creeks to open ocean. Bacterial genetic and physiologic profiles are correlated to one another along the transect and throughout the year. Similar profiles are obtained from locations with similar environmental conditions. At a given location, the community exhibits a predictable pattern of response throughout time. Manipulative experiments along the transect are planned for the coming year.
POPULATION STABILITY ON ISLANDS -- Many studies show that populations of mammals exhibit higher densities and greater stability on islands than on adjacent mainlands. We have monitored populations of Microtus pennsylvanicus, Mus musculus, and Oryzomys palustris on two Virginia barrier islands and two nearby sites on the Delmarva Peninsula mainland since October 1995. Microtus and Oryzomys conform more closely than Mus to the expectation of higher abundance and greater stability on the islands. Species differences appear to be more important than site differences in determining population attributes.
ROLE OF SUBSTRATE QUALITY IN NESTING BIRDS -- We have been studying the population dynamics of nesting Gull-billed Terns, in coastal Virginia since 1993. Populations along the Atlantic Coast have been declining, presumably due to loss of habitat, predators, and sea level rise and storm flooding. In 1997, we initiated a study where we added shell material to selected nesting sites to increase elevation (hence, reducing flooding). In spite of this seemingly more attractive habitat alteration, fewer terns nested at the experimental sites than at the control sites. We suspect that perhaps using surf clam shell rather than oyster shell (not available to us) may have been one of the factors involved in the surprising result.
MACROALGAL BIOMASS AND DIVERSITY -- With support from the REU program, we have established 8 stations along two transects across Hog Island Bay that represent a gradient in organic matter input. At each station we measure macroalgal species composition, biomass, production and elemental tissue content at monthly – bi-monthly intervals. These stations will serve as permanent sites for monitoring.
DEVELOPMENT OF COMPARATIVE SITES -- In response to input from the 1997 site review, we are expanding our efforts to develop collaborations that will allow meaningful cross-site comparisons. Addition of the Plum Island (PIE) LTER to the LTER network has accelerated this process by adding a second coastal site to the network. We have collaborated with PIE LTER on establishing common topographical references using VCR/LTER Global Positioning System units. High-resolution information on relative and absolute elevations of marsh and land surfaces is critical to conducting meaningful comparisons between sites. In addition, VCR/LTER PI's Linda Blum and Aaron Mills are developing replicates of experiments already deployed on the VCR/LTER at NASA sites in Florida.
Applications of VCR/LTER Research
Planned Activities for 1998-1999
Two major new activities are planned for 1998-1999. The first is the establishment of a large scale, long-term inundation experiment. This experiment will use barriers to alter the patterns of marsh flooding by extending the length of flooding in some areas, while decreasing it in others. In some treatments, monthly pumping will also be used to manipulate seawater levels relative to the marsh. These experimental manipulations will build on an information-base developed during a pumping experiment at a smaller scale in 1994-1997. Establishment of the inundation treatments will be accompanied by an intensive survey of the physical and chemical characteristics of a large number of marsh surfaces. It is anticipated that this experiment will increase our insights into the effects of continued sea-level rise and the relationship between vegetation and tidal flooding.
A second activity will increase the number of replicate herbivore exclosures in place on the barrier islands of the Virginia Coast Reserve. The exclosures will be located in areas of Hog Island and other islands that are expected to undergo a shift from grassland to shrubland within the next decade, to help examine the effects of herbivory on this significant successional shift. The exclosures will be linked to monitoring efforts aimed at mammals and small-scale studies of shrub succession.
The VCR LTER is building new Field Station at Oyster, VA. A grant from the University of Virginia (450K) and from a graduate of the University of Virginia ($1M) are being used to purchase and construct phase one of a new field station for research. Negotiations on the land purchase have taken much longer than anticipated (original plans called for construction starting in 1997), however they are now nearly complete. PIs of the VCR LTER have worked over the last 4 years to reach this point and we expect construction to begin in the Fall of 1998 or Spring of 1999.
Several additional activities will involve interactions with other LTER sites, particularly the new Plum Island (PIE) LTER. PI's Karen McGlathery (UVA) and Iris Anderson, (VIMS) will be participating in cross-site activities with the Plum Island LTER. Details are to be worked out in collaboration with Chuck Hopkinson. Their plan is to measure water column gross and net mineralization at both VCR and PIE. Karen McGlathery will also be participating in collaborative work with Pier Luigi Viaroli,(Sacco Di Goro, Italy) and Rutger de Wit (Bassin d'Arachon, France), also including VCR LTER PI Bob Christian (ECU) on DON cycling in shallow lagoonal systems.
New research is being proposed for the VCR that would potentially link the Plum Island LTER and many other coastal wetland sites. We are planning to measure sea level rise, marsh accretion/elevation changes, and couple these with waterbird habitat use to determine whether marsh lagoonal islands are able to keep pace with sea level rise in selected mid Atlantic coastal lagoons where there is a major concentration of federal trust species of waterbirds. These number almost 100 species of wading birds, seabirds, shorebirds, and waterfowl from southern New England to Virginia. Work with Don Cahoon from the National Wetlands Research Center, and J. Allen and C. Roman from URI's Coastal Research Lab (now part of USGS Patuxent Wildlife Research Center) is being coordinated by VCR/LTER PI R. Michael Erwin, and S.E.T. devices will be installed in marshes in summer 1998 in New England. In 1999, the plan is to include the Virginia Coast Reserve as a second site.
Cross-Site & International Activities
Activities for Iris Anderson
Activities for Linda K. Blum:
Activities for Robert R. Christian:
Activities for Frank P. Day:
Activities for Karen J. McGlathery
Activities for John H Porter:
The VCR LTER Information Management System was extensively revamped during late 1996 and early 1997. A major step was taken to allow PI's to directly input and modify metadata (documentation) using online forms on the WWW. The metadata is maintained in a relational database (MSQL) running on a UNIX platform. Using that system 45 datasets were placed online during 1997-1998. VCR/LTER data can be accessed at: http://www.vcrlter.virginia.edu/data.html.
WWW System Use -- The VCR LTER WWW server transferred 807,458 files during May 1997-May 1998. This included an average of 939 requests per day for WWW pages (not graphics). There were a total of 66,520 different computers accessing the system during that period. Educational users made up the largest single block of users, comprising 46% of overall requests and 47% of all bytes downloaded. 110 different countries were identified among the user-base. Detailed weekly usage logs are available at http://www.vcrlter.virginia.edu/usage/.
With a supplement from NSF we will be strengthening our program for archiving physical samples. This activity will be conducted in partnership with the Virginia Museum of Natural History. We will be cataloging existing and new samples and placing the catalog online via the WWW. Samples will include a variety of tissue samples (suitable for genetic and stable isotope analyses), a herbarium and soil and water samples.
Other Grants at VCR/LTER Site
Frank P. Day -- Atlantic White Cedar Restoration: Monitoring for Ecosystem Services and Self Maintenance EPA (subcontract from Christopher Newport University). $166,317
Frank P. Day -- Belowground plant responses to carbon dioxide enrichment DOE (subcontract from Smithsonian Institution) $131,250
Craig Kochel -- Undergraduate Research Fellowship (support of Nicole Bailey) Bucknell University $2,200
Robert R. Christian -- Contributions to the long-term modeling tier of MODMON State of North Carolina, Div. of Environmental Health and Natural Resources, through UNC WRRI $10,399
Patricia Wiberg -- Generation of non-point source pollution and flood waters: identifying source areas from considerations of soil moisture dynamics U.S. Geological Survey and Virginia Water Resources Research Center
Donald R. Young -- Interacting biotic mechanisms that control shrub establishment on Atlantic Coast barrier islands Jeffress Memorial Trust $9,910
Donald R. Young -- Revegetation of coastal spoils on Swash Bay, Virginia VA Dept. of Environmental Quality $27,018
Donald R. Young -- Monitoring revegetated spoils in Swash Bay, Virginia VA Dept. of Environmental Quality $12,722
Karen J. McGlathery -- Nitrogen Cycling in a Lagoonal Land-Margin Ecosystem: Importance of Dissolved Organic Nitrogen NSF $71,230
John D.Albertson -- Generation of Non-Point Source Pollution and Flood Waters: Identifying Source Areas from Considerations of Soil Moisture Dynamics USGS $24,288
John D. Albertson -- Anthropogenic and Topographic Controls on Transition of Coastal Marshes Virginia Water Resources Research Center $5,000.
John D. Albertson -- Experimental Investigation of Soil Moisture-Runoff Dynamics Virginia Water Resources Center $10,000
R. Michael Erwin -- Habitat Restoration for terns in coastal Virginia US Fish and Wildlife Service $8,000
John H. Porter, R. Michael Erwin, R. Dueser et al. Ecosystem research on the Virginia Coast Reserve: Conservation within Dynamic Landscapes. The Nature Conservancy. $114,968.
Mark M. Brinson -- Donald R. Cahoon Southern Science Center, Biological Resource Division, U.S. Geological Survey
Robert R. Christian -- Christine French NSF and Network Office
R. Michael Erwin -- James D. Nichols Patuxent Wildlife Research Center - USGS
R. Michael Erwin -- Jeff S. Hatfield Patuxent Wildlife Research Center - USGS
R. Michael Erwin -- Barry R. Truitt The Nature Conservancy
R. Michael Erwin -- Laura Mitchell Chesapeake Field Office, US Fish and Wildlife Service
Anderson, I. C., Tobias, C. R., Neikirk, B. B., Wetzel, R. L. 1997. Development of a Process-based Nitrogen Mass Balance Model for a Virginia Spartina alterniflora Salt Marsh: Implications for Net DIN Flux. Marine Ecology Progress Series 159:13-27.
Conn, C.E. and F.P. Day. 1997. Root decomposition across a barrier island chronosequence: litter quality and environmental controls. Plant and Soil 195:351-364.
Crawford, E.R. and D.R. Young. in press. Comparison of gaps and intact shrub thickets on an Atlantic Coast barrier island. American Midland Naturalist
Crawford, E.R. and D.R. Young. in press. Spatial/temporal variations in shrub thicket soil seed banks on an Atlantic Coast barrier island. American Journal of Botany
Dilustro, J.J. and F.P. Day. 1997. Aboveground biomass and net primary production along a Virginia barrier island chronosequence. Amer. Mid. Nat. 137:27-38.
Erwin, R.M., J.D. Nichols, T.B. Eyler, D.B. Stotts, and B.R. Truitt. in press. Modeling colony-site dynamics: A case study of Gull-billed Terns in coastal Virginia. Auk
Erwin, R.M., T.B. Eyler, D. B. Stotts, and J.S. Hatfield. in review. Aspects of chick growth in Gull-billed Terns in coastal Virginia. Colonial Waterbirds
Hayden, B. P. 1998. Ecosystem feedbacks on climate at the landscape scale. Phil. Trans. R. Soc. Lond. B 3553, 5-18.
Michener, W.K., E.R. Blood, K.L. Bildstein, M.M.Brinson, and L.R. Gardner. 1997. Climate change, hurricanes and tropical storms, and rising sea level in coastal wetlands. Ecological Applications 7:700-801.
Shao, G., D.R. Young, J.P. Porter and B.P. Hayden. 1998. An integration of remote sensing and GIS to examine the response of shrub thicket distributions to shoreline changes on Virginia barrier islands. Journal of Coastal Research 14:299-307.
The Working Group on Sea Level Rise and Wetland Systems (includes Christian and Brinson). 1997. Conserving coastal wetlands despite sea level rise. Eos 78:257, 260-261
Bledsoe, C.S., T.J. Fahey, R. Ruess, and F.P. Day. in press. Measurement of static root parameters - biomass, length, distribution. In G.P. Robertson, C.S. Bledsoe, D.C. Coleman, and P. Sollins. Standard Soil Methods for Long-Term Ecological Research. Oxford University Press, New York.
Christian, R. R., L. Stasavich, C. Thomas, and M. M. Brinson. in review. Reference is a moving target in sea-level controlled wetlands. In M. P. Weinstein and D. A. Kreeger. Proceedings of "Concepts and Controversies in Tidal Marsh Ecology". Kluwer, Dordecht,The Netherlands
Christian, R. R., M. Naldi, P. Viaroli. 1998. Construction and analysis of static, structured models of nitrogen cycling in coastal ecosystems. Mathematical Modeling in Microbial Ecology. Chapman Hall, New York :162-195.
Fahey, T.J., C.S. Bledsoe, F.P. Day, and R. Ruess. in press. Root production and demography. In G.P. Robertson, C.S. Bledsoe, D.C. Coleman, and P. Sollins. Standard Soil Methods for Long-Term Ecological Research. Oxford University Press, New York
Hayden, B. P. 1998. Regional Climate and the Distribution of Tallgrass Prairie. Pages 19-34 in A. Knapp, J. Briggs, D. Hartnett, and S.Collins. Grassland Dynamics: Long-Term Ecological Research in Tallgrass Prairie. Oxford University Press. NY.
Henshaw, D.L., M. Stubbs, B.J. Benson, K.S. Baker, D. Blodgett and J.H. Porter. 1998. Climate database project: a strategy for improving information access across research sites. In William K. Michener, John H. Porter, and Susan G. Stafford. Data and information management in the ecological sciences: a resource guide. LTER Network Office, University of New Mexico, Albuquerque, NM.
Michener, W.K., J.H. Porter, and S.G. Stafford. 1998. Data and information management in the ecological sciences: a resource guide. LTER Network Office, University of New Mexico, Albuquerque, NM.
Porter, J.H. in press. Scientific databases for environmental research. In. Ecological Data (W.K. Michener, ed). Blackwell Scientific, London.
Porter, J.H. 1998. Providing information on the World-Wide Web. In William K. Michener, John H. Porter, and Susan G. Stafford. Data and information management in the ecological sciences: a resource guide. LTER Network Office, University of New Mexico, Albuquerque, NM.
Porter, J.H. 1998. Scientific databases for environmental research. Pages in William K. Michener, John H. Porter, and Susan G. Stafford. Data and information management in the ecological sciences: a resource guide. LTER Network Office, University of New Mexico, Albuquerque, NM.
Seastedt, T. R., B. P. Hayden, C. E. Owensby and A. K. Knapp. 1998. Climate change, elevated CO2, predictive modeling: past and future climate change scenarios for the tallgrass prairie. Pages 283-300 in A. Knapp, J. Briggs, D. Hartnett, and S. Collins. Grassland Dynamics: Long-Term Ecological Research in Tallgrass Prairie. Oxford University Press. NY.
Theses and Dissertations
Bailey, Nicole. 1998. Hydrogeomorphic Control of Landforms and Vegetation on Southern Parramore Island, Virginia Coast Reserve. Bucknell University, Department of Geology, Honors Thesis, 160pp.
Cannon, Takisha A. 1998. A comparison of microbial food webs in tidal marsh creeks of Northhampton County, Virginia.Master's Thesis, University of Virginia pp. 122.
Elliott, M.T. 1997. Influences of tidal litter (wrack) and microtopography on strand species and on community composition. MS thesis. Virginia Commonwealth University, Richmond, VA
Sullivan, H.J. 1998. Ant distribution patterns and the potential dispersal of root endosymbionts in a strand environment. MS Thesis, Virginia Commonwealth University, Richmond, VA
Bailey, N., Kochel, R.C., and Carlson, C.R., . 1998. Barrier Island Landform and Vegetation Response to Coastal Process Variables on the Virginia Coast Reserve. Geological Society of America Abstracts with Programs 30, n.4:2.
Barimo, J.F. 1998. Zonation patterns in Orthoptera (Acrididae) distribution and plant-herbivore interactions in relation to primary succession on a Virginia barrier island. MS thesis. Virginia Commonwealth University, Richmond, VA.
Barimo, J.F. and D.R. Young. in review. Insect-plant-environmental interactions in relation to primary succession in a coastal ecosystem. Oecologia
Brinson, M. M., and R. R. Christian. in review. Stability and response of Juncus roemerianus patches in a salt marsh. Wetlands
Christiansen, T. 1998. Sediment Deposition on a Tidal Salt Marsh. Dissertation. University of Virginia, Charlottesville VA pp. 134.
Erwin, R.M., T.B. Eyler, J.S. Hatfield, and S. McGary. in review. Diets of nestling Gull-billed Terns in coastal Virginia. Colonial Waterbirds
Joy, D.A. and D.R. Young. in review. Promotion of mid-successional seedling establishment by Juniperus virginiana in a coastal environment. Plant Ecology
Murray, L.A., and J.D. Albertson. 1998. Space-Time Variability of Soil Moisture Along a Small Field Transect. Transactions of the American Geophysical Union pp. 1998 Spring Meeting.
Viaroli, P., and R. R. Christian. in review. Description of trophic status through dissolved oxygen fluxes: application to a shallow coastal lagoon. Journal of Coastal Research
Wijnholds, A.E. and D.R. Young. in review. Interdependence of the host plant, Myrica cerifera, and the actinomycete, Frankia, in a coastal environment. Journal of Coastal Research