FINAL REPORT FOR AWARD # 9411974
| Bruce P Hayden ; University of Virginia LTER: Disturbance Succession and Ecosystem State Change at the Virginia Coast Reserve: LTER III |
Partner Organizations:
The Nature Conservancy:
Financial Support; In-kind Support; Facilities; Collaborative Research; Personnel Exchanges
The Nature Conservancy owns most of the land on which our research is conducted.
NASA Aeronet Sun Photometer (CIMEL)
Help provide long term archive for research specimens
Patuxent Wildlife Research Center, Laurel, MD, Investigator R.M. Erwin
Investigator R. Christian serves as its representative to support Coastal-Global Oceanographic System development.
R. Christian works with Modeling and Monitoring of the Neuse River Estuary, NC (ModMon); a program sponsored by the State of North Carolina to assess the consequences of reducing nitrogen loading to that system. Other institutions involved are University of North Carolina-Chapel Hill, North Carolina State Univ., Duke Univ., and UNC-Charlotte. This program helps provide comparative information for our work in Virginia.
In conjunction with International LTER research, R. Christian participates in the Northern Adriatic Initiative, an international program currently supported by NOAA to develop a long-term program to evaluate the environmental health of that system. Scientists come from Univ. of Maryland; NC State Univ.; Scripps Inst. of Oceanography; Center for Marine Research, Rovinj, Croatia; Marine Biological station, Piran, Slovenia; Laboratory of Marine Biology, Trieste, Italy.
Under EPA Funded project, L. Blum is conducting comparative studies with VCR/LTER ecosystems
Investigator Iris Anderson has been working with Hydrobiological Institute, Czech Academy of Sciences, Ceske Budejovice, CR
Investigator Iris Anderson collaborated with USDA Forest Service Research, Riverside CA
Other collaborators:
We have many individual collaborators and contacts. They are listed below by investigator: --- Karen McGlathery --- Carl Fredrichs, Virginia Institute of Marine Sciences Morten Pedersen, Roskilde University, Denmark. ---John Porter ---- Matt Jones and Rudolf Nottrott (National Center for Ecological Analysis and Synthesis) and James Brunt (LTER Network Office, UNM) on development of Ecological Metadata ---Don Young ---- Dr. Greg Plunkett and Dr. John Anderson are helping to document genetic variation within and between populations, as well as the spread of, the invasive grass Phragmites australis. Both Plunkett and Anderson are Assistant Professors of Biology at VCU. --Iris Anderson--- Jarda Vrba, Jiri Kopacek, Vera Straskrabova, Hydrobiological Institute, Czech Academy of Sciences, Ceske Budejovice, CR Mark Poth, USDA Forest Service Research, Riverside CA Chuck Hopkinson, Woods Hole Biological Lab, Woods Hole, MA Carl Fredrichs, Virginia Institute of Marine Sciences. --- Mark Brinson --- Donald Cahoon of USGS Biological Resources Division - Collaboration on sediment elevation data. Dr. Donald Cahoon, US Geological Survey, National Wetlands Research Center, Lafayette, Louisiana. --- Bob Christian ---- Daniel Baird, University of Port Elizabeth, Port Elizabeth, South Africa. Collaborate on network analysis and co-conveners of session on that topic at ERF 99 Graciella Ramirez, Inter Amercan University of Puerto Rico. ---Linda Blum --- Collaborations with a variety of scientist including Donald Cahoon (USGS), Ron Brockmeyer (St. John's River Water Management District), William Knott (NASA), Ross Hinkle (Dynamac Corp.), Marc Epstein (USFWS), and Douglas Scheidt (Dynamac Corp.) on comparative study between the VCR LTER and Merritt Island National Wildlife Refuge, FL.
Activities and findings:
Research and Education Activities:
VCR LTER III focused on ecosystem change: disturbance, succession and state change in a coastal barrier island, lagoon and mainland complex. Our central hypothesis was that ecosystem, landscape and succession patterns are controlled by the relative vertical positions of the land, sea, and fresh groundwater table. Large transient and small progressive changes in the position of these free surfaces result in disturbance of ecosystem processes and in physiological stresses that may lead to system state change. Variations in the elevations of these critical surfaces result from local weather or climate change, such as short-term storm-generated fluctuation in sea/land levels or long-term sea level rise. Ecological processes, including species extinction and invasion that alter rates of erosion and deposition also affect the positions of these free surfaces relative to one another. In many instances, the joint effects of contemporaneous disturbances at different temporal and spatial scales result in state changes, such as shifts upland to marsh or grassland to shrubland. We have produced 99 journal articles. In addition, VCR PIs have contributed 34 book chapters or published proceedings. Forty eight graduate theses and dissertations were completed, with an additional 7 undergraduate honors theses. Regional research during VCR/LTER III focused on three major areas: environmental history of the site, faunal biogeography, and storm-driven ecosystem disturbances. Constructing the history of the site has proceeded at two major levels. Oertel and his students have studied the changes the site has undergone since the Pleistocene using foraminifera (Oertel et al. 1996, Woo et al. 1997), pollen (Woo et al. 1998), stratigraphic analyses (Foyle & Oertel 1994, Foyle & Oertel 1997) and analysis of landforms (Oertel & Woo 1994, Oertel & Foyle 1995). For a more recent period, Shao, Young and others used remote-sensing linked to ground surveys and historical maps to quantify dramatic changes in the distribution of Myrica cerifera shrubs on the barrier islands since 1942 (Hayden et al. 1995; Young et al. 1995a,b; Shao et al. 1998). The distribution of mammalian fauna across the islands and marshes of the VCR were analyzed using a variety of sampling and genetic techniques (Loxterman 1995, Moncrief et al. 1997, Moncrief & Dueser 1998, Loxterman et al.2000). Mike Erwin and his colleagues have analyzed on habitat and breeding dynamics of water birds on the islands and marshes (Erwin 1996, 1997; Erwin et al. 1996a, b, 1998a, b, 1999 a, b; Eyler et al. 1999). Changes in climatic patterns that generate storms have dramatic impacts on the island system (Davis et al. 1995, Davis et al. 1997, Hayden 1999, 2000). A surprising conclusion was that there were periods where the geographic patterns of shoreline accretion and erosion reversed (Fenster and Dolan 1994). The most recent of such reversals were in the early 1870s and the late 1960s. Barrier Islands. The distribution patterns of five woody species common along a 120 year, island terrestrial chronosequence on Hog island were distinguished based on differences in salinity and flood tolerance (Tolliver et al. 1997). M. cerifera shrub thicket distribution was especially sensitive to changes in shoreline accretion and erosion and associated changes in disturbance frequency and salt input (Shao & Shugart 1997). Juniperus virginiana was found to be both salt tolerant and drought tolerant, which explains its abundance across most of the terrestrial microhabitats. Moreover, it may accelerate the establishment of other woody species by acting as a nurse plant (Joy and Young 2000). Successional dynamics were evident at either end of the chronosequence where vegetation colonized frequently disturbed sites (oceanside) or where M. cerifera shrub thickets were collapsing and being invaded by many species (bayside). Gaps, which were most prevalent in the oldest M. cerifera thickets, were important for increasing species diversity (Crawford & Young 1998). Soil seed banks, the precursor to later successional communities, were most diverse within gaps in the oldest thickets. Swales had more fine root biomass than the dunes largely due to higher nitrogen levels and higher water table (Stevenson & Day 1996). Nitrogen additions on Hog Island dunes increased plant biomass, with greater allocation to shoots than roots (Day 1996). In response to nitrogen fertilization, soil nitrogen increases were greatest on the oldest dunes while biomass increases were smallest. Aboveground biomass was inversely proportional to nitrogen availability and decreased from younger dunes to the oldest. Vegetation on the oldest dunes may be limited by depth to the fresh groundwater table than to nitrogen. In a minirhizotron study, fertilized plots had greater fine root densities but no change in mortality (Weber & Day 1996). Total aboveground biomass in dunes decreased along the chronosequence on Hog Island (Dilustro & Day 1997). Spartina patens biomass decreased, but Ammophila breviligulata biomass increased from the youngest to the oldest dune. Net primary production did not vary significantly across the chronosequence. A cotton strip decomposition assay identified temperature, water table depth and nitrogen availability as the key regulators of belowground decay on the Virginia barrier islands (Day 1995). Among the Hog Island chronosequence dunes, native root decay increased from young to old dunes (Conn & Day 1997). Among swales, higher water levels and associated soil anoxia inhibited native root decomposition and minimized the effects of litter quality on decay. Root decay on younger dunes increased in response to nitrogen fertilization (Conn & Day 1996). Suppressed lignin degradation on the oldest dune suggested possible negative fertilization effects. Nitrogen appeared to be limiting to root decomposition on younger dunes but not older dunes. The fish assemblages in the barrier island ponds and shallow surf zones off the islands have also received attention. In particular, the temporal and spatial role of abiotic and biotic factors in controlling these assemblages has been addressed (Layman 1999, Layman & Smith 2000, Layman et al. 2000). Lagoons. In 1997, we began a program to describe seasonal patterns of nutrient cycling and metabolism at three sites in Hog Island Bay that represent a gradient in nutrient and organic matter loading. We also established a long-term monitoring program with monthly/bimonthly surveys of primary producer biomass and water/sediment characteristics in the lagoon that complements our long-term water quality monitoring program. Using microcosm experiments, and scaling these to patterns of primary production in the field, we established that the lagoon was net autotrophic during the spring-summer, and net heterotrophic in the fall (McGlathery et al. 2000). Benthic microalgae and macroalgae were responsible for most of the autotrophic production observed and were the dominant temporary sink for nitrogen in the lagoon (McGlathery et al. 2000). Where nutrient loading was low to moderate and herbivore populations large, grazing had an important influence on the net accumulation of macroalgae (Giannotti 1999; Giannotti & McGlathery 2000). Macroalgal biomass peaked in early summer throughout the lagoon. In some locations (mid-lagoon shoals) macroalgae reached densities as high as 650 gdw m-2 and the population crash resulted in anoxia throughout the water column. The net release of dissolved organic and inorganic nitrogen during this dystrophic event was 70 mmol m-2 d-1. At this rate, all the macroalgal-bound N would be remineralized within 7-10 days (Tyler et al., 2000). Gross mineralization was measured in the sediments using 15N isotope dilution techniques. We found that total nitrogen turned over in 7 days or less; however, consumption of N was similar to gross production. These results were supported by microcosm studies which showed net uptake of both ammonium and nitrate by sediments during most seasons, suggesting that inorganic N was removed in the sediments as rapidly as it was formed, either by coupled nitrification - denitrification or by microbial immobilization (Anderson et al., 2000). Dissolved organic nitrogen concentrations in the region were high during all seasons and comprised 55-95% of total dissolved nitrogen. The macroalgae were a net source for dissolved organic nitrogen compounds other than urea, and the sediments also were a significant source of dissolved organic nitrogen to the water column (Tyler et al., 2000). Mainland Margins. At the VCR evidence abounds that sea level rise has eroded salt marshes and sometimes submerged them and that salt marshes have in turn encroached on field and forest. During VCR LTER III we focused on the dynamics of vegetation in the transition zone from marsh to forest. We began a long-term observational and experimental studies at a marsh on the upper reaches of Phillips Creek (Taylor 1995 , Tirrell 1995, Aiosa 1996, Anderson et al. 1997, Tarnowski 1997, Stasavich, 1998, Brinson & Christian 1999, Ricker 1999, Tolley & Christian 1999). We have shown that marsh transgression into forested uplands occurs at rates dependent on the availability of sediments and on the slope of forested surface on which the marsh encroaches as sea level rises (Hmeiliski1994). The upper Phillips Creek high marsh is rich in peat and exhibits a morphology of hummocks and hollows which are typical of salt marshes on formerly forested land (Christian et al. 1999). We also studied the loss of marsh along its tidal creeks and found that erosion of the marsh along the tidal creek banks was slow and progressive except in periods of significant sediment deposition which occurred during extreme high tide usually associated with coastal storms (Christiansen, 1998). As part of our efforts to understand the transition from forest to marsh with rising sea level we developed models that characterize state change in marshes in response to sea level rise. Brinson et al. (1995) modeled expansions and contractions in marsh area based on sediment supply. At the margin of the marsh and the lagoon progradation or erosion was found to depend on sediment supply. Whether a marsh encroached into a forest or stalled depended on the slope of the antecedent forest surface. All four modeled patterns of long-term marsh dynamics were found at the VCR. However eroding marshes dominate at the VCR because of low supply of new terrigenous sediments from the peninsula. We also developed a model that addresses ecosystem state changes in the upland/marsh transition. Furthermore, we identified limiting processes in this sequence of change and the factors that promote or accelerate such changes (Brinson et al. 1995, Christian et al. 1999, Nuttle et al. 1999). Modeling. Models of system dynamics were used to test the collective assemblage of our findings and to formulate new research questions and hypotheses. We developed a hypsometric model of Hog Island Bay (Oertel et al. 1996a, 2000) and have extended it to include the adjacent mainland watersheds. This model is detailed elsewhere in this proposal. Using 150 years of maps, charts and aerial photographs we have build an animated morphometric model of Hog Island and have used this model to project island changes for the next 40 years. Christiansen (1998) constructed a mathematical model of the dynamics of sedimentation in a salt marsh and tested it against observations. Santos (1997) created a hydrologically-based predictive model for island salt flats. Wiberg and Albertson's model for evapotranspiration from salt marshes, and Hayden's model of barrier island vegetation dynamics in response to coastal storms disturbance were completed in late 1999. In collaboration with Carl Fredrichs of the Virginia Institute of Marine Sciences we initated the development of a hydrodynamic model for the lagoon. Synthesis. Hayden et al. (1995) introduced the concept of the geometry of land, sea and water-table surfaces as controlling agents in ecosystem patterns within landscapes and related these controls to the long-term dynamics of the barrier islands, lagoons and marshes of the VCR. Brinson in a series of synthesis papers, focused on wetland function (Brinson et al.1995), environmental mitigation (Brinson & Rheinhardt 1996), hydrologic controls (Brinson et al. 1998), societal values (Brinson & Rheinhardt 1998) and biodiversity in wetlands (Brinson & Verhoeven, 1999). Thomas (1998) applied network analysis to the nitrogen cycling of different marsh states to predict alterations in response to sea level rise. Oertel (1995; 2000 a, b) has continued his synthetic work on the evolution of the VCR landscape at the regional scale in space and at the scale of glacial and interglacial transitions in time showing the connection between relict drainage patterns on the continental shelf and existing lagoonal landscapes. The central idea was that the antecedent Pleistocene land surface was a controlling legacy for the modern landscape. This notion is in stark contrast to the idea that barrier island lagoons, like lakes, were merely basins that fill with sediments that evolve into terrestrial landscapes. In modeling waterbird colony site damages through time, Erwin et al. (1998) have developed a method for quantifying how a number of extrinsic factors influence patch use dynamics. Population genetic modeling has revealed the degree to which small mammals may also be viewed as a large barrier island metapopulation (Moncrief et al. 1997). At the LTER Network level and as part of a long-standing network-wide synthetic activity to better understand the mechanisms for ecosystem controls on climate, Hayden (1998) published Ecosystem Controls on Climate at the Landscape Scale in the Transactions of the Royal Society of London. This work was part of the VCR contribution to climate research in the LTER network. Hayden (1998a, b) also joined scientists at the Konza Prairie LTER in the completion of the first in the LTER Network / Oxford Press synthesis series on long-term ecological research. These two papers focus on climate controls on the Prairie and the impact of climate change. We have been strong participants in LTER Network information management actdivities (Porter et al. 1996; Henshaw et al. 1998; Michener et al. 1998; Porter 1998 a, b; Olson et al. 1999; Porter 2000). During the course of LTER III, we provided over 31 gigabytes of data, text and images to the scientific community and the general public.
Findings:
Six findings from VCR LTER III with system-wide significance will play key roles in research during VCR LTER IV. 1. Christiansen (1998) and Christiansen et al. (2000) found that sedimentation rates on mainland marshes were highest during the storm surge flooding from coastal storms (Nor'easters) and hurricanes. The role of disturbance in the upward growth of marshes in response to sea level rise had not been quantified prior to this work. For comparison, on the ebb tide flow off the marsh no sedimentation or export of sediment from the marsh was recorded in two years of observation. Disturbance of another sort involved marsh surface erosion. Observations during hurricane Bertha in 1996 suggests that sediment loss from marshes may occur during heavy rains at low tide due to the erosive power of raindrops. 2. In 1999, the eelgrass Zostera marina, locally extinct since 1933, returned to the VCR. Z. marina was the keystone species of the sandy bottoms of the lagoons. Historical and anecdotal information confirm that following the demise of the eelgrass the lagoon sediments were mobilized, waters became turbid, the bay scallop and other important filter feeders disappeared and with that many water fowl species no longer returned. Over the next three decades, we expect a major ecosystem state change in the lagoons of the VCR. Resuspension of lagoon sediments will be reduced, water clarity improved and the former communities of benthic flora and fauna will return to the lagoons of the VCR. 3. Through measurements of water table elevations in groundwater wells and short-term injection experiments, we found that the horizontal flow rates of freshwater, nutrients and microbes from mainland agricultural systems toward the marshes was around 70 m/yr (Callaghan 1999). Given the size of VCR mainland, terrestrial watersheds one would expect turnover times of 4 to 8 decades. As this turnover time spans the period of introduction of modern fertilizers on Virginia's Eastern Shore, future estuarine eutrophication from past nutrient loading, already in the pipeline, is likely. We will monitor landuse change by remote sensing (GIS), monitor water chemistry in 56 terrestrial watersheds, and measure the short-term groundwater processes driven by extreme events a representative watershed. 4. Hog Island fringing marshes range from 1 to 150+ years in age. While a 'climax' monoculture of Spartina alterniflora quickly establishes itself, a multi-decade succession in the marsh sediment chemistry and communities of organisms that use the marsh takes place (Walsh 1998, Silliman 1999, Silliman & Zieman 2000, Walsh & Zieman 2000). The associated creeks were found to aid in the retention of nutrients in young marsh/creek systems, and thereby accelerate the development of the marsh (Tyler 1997, Tyler & Zieman 1999). These chronosequences are long-term natural experiments in which new landscapes continue to be generated through storm-generated sedimentation events that convert shallow lagoon areas into marshes (a state change). We will continue to track the evolution of this chronosequence as new marshes evolve. 5. A synthetic system property resulting from prior research that will guide future research is the concept of joined terrestrial-marine watersheds and the hypsometric model of their land surface elevations. Our 18,860 station, bathymetric survey of Hog Island Bay (Oertel et al. 1996, 2000) coupled with USGS digital elevation model data for the terrestrial part of the system now permits us to incorporate watershed concepts into our work and place all of our research locations into a common watershed framework. More importantly it will permit system-level mass budget modeling research to be initiated. 6. Finally, herbivory studies in VCR LTER III indicated the important role played by topdown controls in grass/shrub communities (Barimo 1998, Barimo & Young 2000) and marsh communities (Silliman 1999, Silliman & Zieman 2000) and macroalgal communities (Giannotti and McGlathery 2001). A complete list of VCR LTER III publications is appended as a PDF file. Selected publications are highlighted in the publications section of this report.
Training and Development:
The VCR/LTER is engaged in training activities at a variety of levels. Students participating in the VCR/LTER project defended 48 graduate theses or dissertations during the period of this grant. All Ph.D students are required to submit their dissertation for publication and most of our masters degree students also publish the results of their research. Students are trained in research techniques and (more importantly) the scientific method. In addition to university-level studies, the VCR/LTER is a participant in LTER network-wide activities to promote a partnership between LTER sites and K-12 education. Using supplemental support from NSF, PIs David Smith and Karen McGlathery and staff member C.R. Carlson are working with teachers at the Northampton County High School to create new learning opportunities for students. In addition, through a supplement to support LTER and SLTER networking, we were able to help the Northampton Co. school system upgrade and replace outdated and failing network infrastructure that was posing a bottleneck for effective use of network resources, both at the VCR/LTER and elsewhere. Two graduate students participated in an ILTER trip to view research sites in Japan. VCR/LTER graduate student A. Christy Tyler played a leadership role in the LTER Network student group. She arranged several meetings of LTER students at national scientific meetings and helped to facilitate improved electronic networking. This 'student-to-student' networking provides an important form of informal training.
Outreach Activities:
During the course of VCRLTER III there was a wide array of outreach activities. The most intensive effort was a two day media workshop was conducted by the VCR/LTER in conjunction with the University of Virginia Media Office during late May 1999. VCR/LTER investigators L.K. Blum, R.M. Erwin, B.P. Hayden, J. H. Porter, and J.C. Zieman, along with collaborators B. Truitt and M. Luckenbach provided both overviews of the ecological forces that dominate barrier island systems and detailed research results that result directly from VCR/LTER research. The press also participated in a tour of the VCR/LTER's Hog Island Chronosequence study site was lead by Bruce Hayden and John Porter. The media workshop resulted in a 1/2-hour Virginia Public Radio program ('With Good Reason') based on the trip across Hog Island, and an article in the Washington Times on the changes Hog Island has undergone in the last 100 years. VCR/LTER researchers are active participants in numerous scientific societies, such as the Ecological Society of America and the Estuarine Research Federation, with multiple presentations by VCR/LTER PIs and students made annually. VCR/LTER researchers have also been active in developing the International Long-Term Ecological Research Network (ILTER). PI Robert Christian participated in several activities aimed at fostering ILTER and Global Terrestrial Observing System (GTOS) in Italy, Slovenia and Croatia and meetings with ministry personnel in Croatia and Slovenia to describe the nature of LTER and ILTER. He is also involved in developing the Coastal Global Oceanographic Observation System and served as the respresentative of GTOS for the panel developing the program. PI Iris Anderson has been involved with the ILTER network in the Czech Republic both in developing a joint research project with Czech scientists at the Hydrobiological Institute of the Czech Academy of Science in Ceske Budejovice and in presenting results of our research at the International Association of Landscape Ecology, held in Prague. PI John Porter has been involved in the development of information systems to support long-term research at the international level. This included working with latin american information managers within the ILTER network at the regional meeting in Puerto Ordaz, Venezuela and training of central european information managers at a week-long workshop in Vacratot Hungary. He also made a presentation and conducted a workshop of LTER information management at the International Congress of Ecology in Florence Italy.
Journal Publications:
| Anderson, I. C., Tobias, C. R., Neikirk, B. B., Wetzel, R. L., "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, vol. 159, (1997), p. 13. Published |
| Brinson, M. M., "The role of reference wetlands in functional assessment and mitigation", Ecological Applications, vol. 6, (1996), p. 69. Published |
| Brinson, M. M., R. R. Christian, and L. K. Blum, "Multiple States in the Sea-Level Induced Transition from Terrestrial Forest to Estuary", Estuaries, vol. 18, (1995), p. 648. Published |
| Christian, R. R., E. Fores, F. Comin, P. Viaroli, M. Naldi, and I. Ferrari, "Nitrogen cycling networks of coastal ecosystems: Influence of trophic status and primary producer form.", Ecological Modelling, vol. 87, (1996), p. 111. Published |
| Conn, C. E., and F. P. Day, "Root decomposition across a barrier island chronosequence: litter quality and environmental controls", Plant and Soil, vol. 195, (1997), p. 351. Published |
| Erwin, R. M., "Dependence of waterbirds and shorebirds on shallow-water habitats in the mid-Atlantic coastal region: an ecological profile and management recommendations", Estuaries, vol. 19, (1996), p. 213. Published |
| Hayden, B. P., "Ecosystem feedbacks on climate at the landscape scale", Philosophical Transactions of the Royal Society of London Series B-Biological Sciences, vol. 353, (1998), p. 5. Published |
| Howarth, R., D. Anderson, J. Cloern, C. Elfring, C. Hopkinson, B. Lapointe, T. Malone, N. Marcus, K. McGlathery, A. Sharpley, and D. Walker, "Nutrient Pollution of Coastal Rivers, Bays and Seas", Ecological Issues, vol. 7, (2000), p. 2. Published |
| Loxterman, J. L., N. D. Moncrief, R. D. Dueser, C. R. Carlson, and J. F. Pagels, "Dispersal abilities and genetic population structure of insular and mainland Oryzomys palustris and Peromyscus leucopus", Journal of Mammalogy, vol. 79, (1998), p. 66. Published |
| Olson, R. J., J. M. Briggs, J. H. Porter, G. R. Mah, and S. G. Stafford., "Managing Data from Multiple Disciplines, Scales, and Sites to Support Synthesis and Modeling", Remote Sensing Environment, vol. 70, (1999), p. 99. Published |
| Osgood, D. T., and J. C. Zieman, "The influence of subsurface hydrology on nutrient supply and smooth cordgrass (Spartina alterniflora) production in a developing barrier island marsh", Estuaries, vol. 21, (1998), p. 767. Published |
| Shao, G. F., D. R. Young, J. H. Porter, and B. P. Hayden, "An integration of remote sensing and GIS to examine the responses of shrub thicket distributions to shoreline changes on Virginia Barrier Islands", Journal of Coastal Research, vol. 14, (1998), p. 299. Published |
| Tyler, A. C., and J. C. Zieman, "Patterns of development in the creekbank region of a barrier island Spartina alterniflora marsh", Marine Ecology-Progress Series, vol. 180, (1999), p. 161. Published |
| Young, D. R., G. Shao, and M. M. Brinson, "The impact of the October 1991 northeaster storm on barrier island shrub thickets (Myrica cerifera)", Journal of Coastal Research, vol. 11, (1995), p. 1322. Published |
| Baker, K. S., B. Benson, D. L. Henshaw, D. Blodgett, J. H. Porter, and S. G. Stafford, "Evolution of a Multi-Site Network Information System: the LTER Information Management Paradigm", Bioscience, vol. 50, (2000), p. 963. Published |
| Day, F. P., "Effects of nitrogen availability on plant biomass along a barrier island dune chronosequence", Castanea, vol. 61, (1996), p. 369. Published |
| Hayden, B. P., M. Santos, G. F. Shao, and R. C. Kochel, "Geomorphological Controls on Coastal Vegetation at the Virginia-Coast-Reserve", Geomorphology, vol. 13, (1995), p. 283. Published |
| Brinson,
M. M., R. D. Smith, D. F. Whigham, L. C. Lee, R. D. Rheinhardt, and W. L.
Nutter, "Progress in development of the hydrogeomorphic approach for assessing
the functioning of wetlands" , bibl. Gleneagles Publishing, Adelaide, Australia.,
(1998). Book Published
of Collection: A. J. McComb and J. A. Davis, "Wetlands for the Future" |
| Christian, R. R., C. French, J. Gosz, and R. Waide, "Perspectives
on international long term ecological research" , bibl. Backhuys Publishers,
Leiden, NL., (1999). Book Published
of Collection: A. Farina, "Perspectives in ecology: a glance from the VII International Congress of Ecology (Florence 19-25 July 1998)" |
| Fahey, T. J., C. S. Bledsoe, F. P. Day, R. Ruess, and
A. Smucker, "Root production and demography" , bibl. Oxford University Press,
New York., (1999). Book Published
of Collection: G. P. Robertson, C. S. Bledsoe, D. C. Coleman, and P. Sollins, "Standard Soil Methods for Long-Term Ecological Research" |
| Oertel, G. F., and J. Kraft, "New Jersey and Delmarva barrier islands" , bibl. Springer-Verlag, Heidelberg, Germany, (1994). Book Published
of Collection: R. A. Davis, "Geology of Barrier Islands" |
| J.H. Porter, "Scientific databases" , bibl. Blackwell Science Ltd., London, UK., (2000). Book Published
of Collection: W. K. Michener and J. Brunt, "Ecological Data: Design, Processing and Management" |
| Seastedt, T. R., B. P. Hayden, C. E. Owensby, and A. K.
Knapp, "Climate change, elevated CO2, predictive modeling: past and future
climate change scenarios for the tallgrass prairie" , bibl. Oxford University
Press, New York., (1998). Book Published
of Collection: A. Knapp, J. Briggs, D. Hartnett, and S. Collins, "Grassland Dynamics: Long-Term Ecological Research in Tallgrass Prairie" |
Other Specific Products:
Physical collection (samples, etc.)In addition to providing information on the Internet, the VCR LTER
also has an active program aimed at the preservation of physical and
biological samples, in partnership with the Virginia Museum of Natural
History. Since 1989 Drs. Dueser and Moncrief have collaborated on
studies of mammalian island ecology and biogeography at the VCR/LTER.
They have supervised graduate student projects that directly examined
inter-island movement in rodents (Forys and Dueser, 1993, American
Midland Naturalist, 130:408-412). Archived frozen tissue samples
allowed examination of gene flow in those same populations (Forys and
Moncrief, 1994, Virginia Journal of Science, 45:3-11 ), as well as
gene flow and genetic population structure in two species of rodents
with different dispersal abilities (Loxterman et al., 1998, Journal of
Mammalogy, 79:66-77). Noninvasive tissue sampling (earclips),
initiated in 1995 as part of capture-mark-recapture studies at two
island and two mainland sites, has produced frozen tissue samples from
more than 2000 individuals representing 5 species of rodents.
Preliminary analyses of microsatellite DNA loci in one of those rodent
species (Moncrief et al., 1997, Molecular Ecology, 6:299-301) yielded
several genetic markers for investigating population substructuring
and movement of individuals.
Biogeographic surveys of insular and mainland small mammal
populations (primarily rodents) have been conducted by Dr. Dueser in
collaboration with other researchers since 1975. Multi-site surveys
were conducted during 1988, 1989, 1993, 1994, 1998 and 1999. Since
1989, tissue samples and voucher specimens have been collected from 18
islands and 11 mainland sites and deposited in the mammal collection
at VMNH. To date we have archived more than 1500 vials of frozen
tissues (heart, liver, kidney, and skeletal muscle) along with
vouchers of more than 850 individuals representing 12 species from the
Virginia barrier islands and southern Delmarva peninsula. During the
past year, Moncrief and Dueser were awarded outside funding to study
the distribution and inter-island movement of mammalian predators
(raccoons and red foxes) on the Virginia barrier islands. Earclips
and hair samples from each animal handled as part of that project are
being archived for future genetic and stable-isotope studies.
An archiving committee consisting of PIs Zieman, Erwin, Macko and
collaborator Moncrief oversee the archive and make recommendations
regarding sample collection and archiving within the VCR/LTER.
Specimens are made available following the standard procedures of the Virginia Museum of Natural History, Martinsville, VAData or databases Datasets available from the VCR/LTER are: ALM7D8802A: Temporal and spatial distribution of microbial biomass, growth and activity. BPH8801A: LTER hurricane record for the Virginia Coast Reserve. BPH8801B: Long-term precipitation for the Virginia Coast Reserve 1837-1987. GFO9107A: Trend surface analysis of the 300 YBP stratigraphic horizon and the Holocene/Plestocine boundary HHS8801A: Establishment of island transects. HHS8802A: Plant distribution on Hog Island. JCZ8801A: Element and biomass partitioning on the VCR landscape, part A. JCZ8801B: Element and biomass partitioning on the VCR landscape, part B. LKB2E8802A: Spartina alterniflora decomposition in marsh sediments. LML7O9001A: A study of water quality conditions in the tidal creeks of Northampton County, Vs Bayside LML7O9001B: A study of water quality conditions in the tidal creeks of Northampton County, Vs LML7O9001C: A study of water quality conditions in the tidal creeks of Northampton County, Vs RAB9001A: Hog and Cobb Island nesting seabird study, part A. RAB9001B: Hog and Cobb Island nesting seabird study, part B. RDD6B7501A: Survey of island small mammals - trapping data. VCR97006: Brownsville and Hog Island Surficial Well Data VCR97008: 1992-93 Parramore Permanent Plot Baseline Data : Site Data VCR97009: 1992-93 Parramore Permanent Plot Baseline Data : Subplot VCR97011: 1992-93 Parramore Permanent Plot Baseline Data : Tree Data VCR97013: 1992-93 Parramore Permanent Plot Baseline Data : Subplot Water Cover VCR97015: Inundation Experiment Permanent Plot Data : Biomass VCR97016: Inundation Experiment Permanent Plot Data : Bulk Density VCR97017: Inundation Experiment Permanent Plot Data : Macroorganic Material VCR97018: Hourly Meteorological Data for the Virginia Coast Reserve LTER VCR97019: Extratropical Storms (1885-1996) by Month (USA) VCR97022: HHS8802B : Plant distribution on Hog Island : T1 : Myrica allometry - dia.+wgt. VCR97023: HHS8802B : Plant distribution on Hog Island : T2 : Myrica allometry - dia.+wgt. VCR97024: HHS8802B : Plant distribution on Hog Island : Myrica allometry - cuttings VCR97025: Bacterial dynamics in tidal marsh creeks of the Eastern Shore of Virginia VCR97026: Distribution of barrier island overwash disturbance VCR97027: Water level fluctuations, Brownsville Marsh - MID MARSH SITE - Stevens water levs VCR97029: Crab Burrows, Soil Nutrients, and Spartina alterniflora : weekly nutrients VCR97030: Crab Burrows, Soil Nutrients, and Spartina alterniflora : organic content VCR97031: Monte-Carlo Simulation Models of Animal Movement VCR97032: Production data from Brownsville Marsh 1992 VCR97035: Plant Cover Upper Phillips Creek VCR97036: Barrier Islands Lagoons and Marshes VCR97037: Shoreline and Upland/Marsh data for Hog Island 1852-1993 VCR97038: Hog Island Small-Mammal Trapping VCR97043: Nitrogen and Phosphorus Content of Decaying Roots VCR97044: Rates of Mass Loss During Root Decay VCR97045: Cotton Strip Decomposition - Tensile Strength Author(s): Frank P. Day VCR97046: Bryson Archeoclimate Model for Painter VA VCR97047: Hog Island Soil Water Nutrient Chemistry 1990-1992 VCR97048: Hog Island Soil Nutrient Data 1991-1992 VCR97049: Hog Island Chronosequence Soil Eh, pH and Temperature 1991-1992 VCR97052: Fertilization Above & Below Ground Biomass and Species Number on Hog Island Dunes VCR97053: Tide Data for Hog Island (1991-), Redbank (1992-). 12 minute interval VCR98054: Birdwood Mammal Trapping Data, Charlottesville, VA, 1974-1978 VCR99056: Ground Water Level on a Parramore Pimple VCR99059: A Spatially Explicit Model of Vegetation-Habitat Interactions on Barrier Beaches VCR99060: GPS Elevations of VCR/LTER Marshes VCR99065: Long-term N-fertilized vegetation plots on Hog Island VCR99066: Groundwater well data - Hog Island VCR99067: Fine Root Biomass on North Hog Chronosequence WKN7S8801B: Groundwater budgets on Hog Island and at Brownsville. WKN7S8802A: Sediment dynamics and organic matter survey in mainland, lagoon, and island marss WKN7S8903A: Morphological study of tidal creeks. WO8802A: Spartina alterniflora leaf measurements, part A. WO8802B: Spartina alterniflora leaf measurements, part B. WO8802C: Spartina alterniflora leaf measurements, part C. Biodiversity Database (Hayden, Porter) - 6,000+ genera Photographic Images - 1400+ images of the site (135 MB) Global Positioning System Projects (Carlson) - GPS Data from 25+ individual GPS surveys (many of which have tens of thousands of individual points) Northampton Co., VA GIS Coverages (Porter, Richardson) - Hydrography, Transportation, Soil and Landuse, Plant Associations, Bird Nesting Sites LIDET experiment data for the VCR/LTER (Blum) Summary Water Quality Data (Brinson, Blum) This data is made freely available over the VCR/LTER web site following the VCR/LTER Data Policy. Researchers have up to 2 years to make their data publicly available or to provide written justification for why sensitive data needs to be withheld (e.g., endangered species). Data users are required to state their name, contact information and reason for requesting the data. During the period of this grant there were 259 requests for data granted. Additional data (e.g., summary reports, images, GIS data) are available without user input are not tracked here. |
http://www.vcrlter.virginia.edu
This is the primary WWW site for the VCR/LTER project.
Contributions:
Contributions within Discipline:
The VCR/LTER continues to advance our understanding of coastal ecosystems through the application of long-term studies and experiments. The long-term data sets being generated by the VCR/LTER are providing a unique record of longer-term responses not generally observed or recognized in shorter-term studies. The examination of our paradigm of linking ecosystem state change to the relationship between free surfaces continues to motivate interesting and innovative collaborative research. As in the Activities and Findings sections, we have broken our contributions down into sections based on the primary free surfaces involved. LAND AND FRESH-WATER FREE SURFACES Our primary goal is to understand the interactions among the three 'free surfaces' and how they affect ecosystem processes across the landscape of the Virginia Coast Reserve. Work by PI Don Young has focused on recently formed swales that are periodically influenced by flooding from sea water and are closely coupled to groundwater reserves. Shrub establishment, a key seral stage in maritime successional models, occurs in these areas. We are beginning to understand how the free surfaces affect or control shrub establishment, leading to thicket formation. More importantly, we are beginning to appreciate the indirect effects of the free surfaces on biotic interactions. These interactions, and their influences on vegetation dynamics are much more important than previously hypothesized for the harsh environment of coastal ecosystems. LAND AND SALT-WATER FREE SURFACES Marshes Salt marshes sit in a unique position within the landscape and across the climate gradient. Their landscape position makes them susceptible to the stress of inundation of salt water, and the pattern of that stress may vary within and among marshes. Furthermore, as they are positioned along the coast they are subject to sea-level change and human activities, such as cultural eutrophication. To add to these stresses are a variety of disturbances that might include wrack (dead plant materials) deposition, severe herbivory by mammals and birds and human manipulations of the landscape. They are both an important ecosystem to be protected and an interesting ecosystem to studied to understand the interactions of ecosystem structure and function with multiple stresses and disturbances. We are addressing these issues in marshes within a region that has received relatively little study of this kind before.More extensive studies have been made to the north and south. Furthermore, we are concentrating our efforts in the upper and inner parts of the marshes and focusing on transitions from one ecosystem state to another. Juncus roemerianus is near its northern limits, tends to thrive best when inundation is not regular, and appears to exist in relic stands. Understanding the dynamics of these stands is of particular importance to understanding their fate in an environment of rapid sea-level rise and climate warming. Although much work has been done on plant communities of marshes and their response to disturbance and stress, less has been done on other ecosystem properties. We have focused on other marsh functions and brought them into the context of ecosystem state change. The waterbird research and monitoring conducted over the past 5-6 years has resulted in some of the first ecological information collected on a species of coastal waterbird (Gull-billed Tern) that appears to be declining in many parts of its range. The research documented unusually slow growth rates of young and unusual diets. Of more broad interest and application is the colony site modeling work. The techniques used in our research could be applied to any animal metapopulation where sites are physically unstable from year to year and discrete habitat types are chosen. Lagoon Coastal lagoons are important land-margin ecosystems along the Atlantic coast, and on most continents, yet they have received far less study than deep river-fed estuaries. Given their high surface area relative to water volume, we expect these systems to respond differently to nutrient and organic matter loading than estuaries. One distincitve feature is the dominance of benthic macrophytes as primary producers. We are asking questions about how these macrophytes influence nutrient cycling processes, and we are relating our process measurements to hyrodynamic characteristics of the lagoon to characterize the flow of nutrients across the landscape. We have determined that organic nitrogen is an important reservoir of fixed nitrogen in this system. Few studies have focused on the fate and transport of land-derived nutrients through these important land-margin systems to the coastal ocean. Megasite Our work continues to define the mammalian species pool of the Delmarva Peninsula. A 1997 survey of North American museum collections revealed the first specimen of the masked shrew (Sorex cinereus) from the Virginia portion of the Peninsula (Moncrief and Dueser 1999). This species has not yet been reported from the islands. We also are making good progress in developing genetic markers useful in the exploration of ecological processes such as colonization and extinction. Ultimately, this work will allow us to assign (relative) rates to the processes which determine species distributions among the islands, and will reveal the relationship between geographic and genetic distance in this watery, highly fragmented landscape. Finally, our work has begun to explain the role of mammalian predation in the decline of colonial and beach-nesting birds on the islands. This work will provide a basis for an ecologically-realistic predator management strategy for the islands. This work is particularly important in a management sense because of the global extent of the problem of predator impact on ground-nesting birds.
Most of our contributions are listed under 'principal discipline' due to the breadth of disciplines that are critical to our understanding of coastal systems. These include ecology, geology and hydrology. We are developing a more lucid understanding of plant-environment interactions in coastal environments. This is leading to improved management plans and restoration/mitigation projects where disturbed coastal environments are revegetated. We have also been active in the development of computer-based information systems suitable for ecological information. The diverse array of data types used by ecologists, geologists and hydrologists confound most conventional database software designed for commercial applications. To this end, we have collaborated on the development of biological metadata standards with others who face the same challenges.
Many of our activites in the development of human resources are listed in the training section of this report. The VCR-LTER project has provided an invaluable training opportunity for numerous undergraduate and graduate students. In addition, during the course of the tern research, PI Mike Erwin was able to use volunteers who were college students, high school teachers, interns with the U.S. Fish and Wildlife Service and with The Nature Conservancy. We also worked with state and other federal agency personnel in the field.
We have made substantial strides in acquiring resources to improve the scientific infrastructure for research on the Virginia Coast Reserve. $2.5 million have been raised from University and private sources to support development of improved laboratory facilities for the VCR/LTER at the University of Virginia Coastal Research Center. We have also received approximately $140,000 of supplemental funding to support the expansion of computer network facilities devoted to the project. As listed in the Internet Products section, we operate an extremely active WWW server that provides resources to all researchers interested in the Virginia Coast, as well as the general public. Also as detailed in the 'Activities' section, we have made substantial progress on developing a strong relationship with the Virginia Museum of Natural History (VMNH) for the management of VCR/LTER physical specimens. We have also greatly expanded our topographic surveys of a number of research sites using survey-quality Global Positioning System (GPS) technology. Site Manager C. Randy Carlson works with students and PIs on the design and analysis of kinematic GPS data, which is then posted on the VCR/LTER WWW page. This detailed topographic data is freely available to all interested researchers.
VCR/LTER research products, although aimed at fundamental scientific questions, are also applicable to management questions. VCR researchers have helped to make their results available in the following ways (listed by investigator): ---Bob Christian ---- Functional assessment and hydrogeomorphology are central to the US mitigation programs for wetlands. We have continued to place our work into these contexts. This has aided our understanding of marshes and made our findings applicable to management. ELOISE (European Land-Ocean Interaction Studies), 2 October 1998. Applications of network analysis to field studies and environmental management. European Association for Environmental Management Workshop, 15 March 1999. Separating functions and values of wetlands and the need for reference (with M. M. Brinson) Marine Station, Piran, Slovenia, 22 March 1999. Bacteria to fish and one ecosystem to another (with David Smith of U. VA) Center for Marine Research, Rovinj, Croatia, 23 March 1999. Bacteria to fish and one ecosystem to another (with David Smith of U. VA) Laboratory of Marine Biology, Trieste, Italy. 26 March 1999. Bacteria to fish and one ecosystem to another (with David Smith of U. VA) --- Linda Blum --- Eastern Shore Water Quality Consortium - Scientific advisor Lake Monticello Water Quality Monitoring Committee - Assist with interpretation of water quality data and the potential impact on Chesapeake Bay ---Raymond Dueser--- Information from predator surveys and tracking will be used by The Nature Conservancy and USFWS to develop strategies for preserving viable nesting habitats for waterbirds. ---John Porter--- Our study of the landscape ecology of colonial waterbirds will be used the The Nature Conservancy in the design and implementation of use policies for their extensive insular land holdings.
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