I. Data Set Descriptors A. Title: Brian R. Silliman. 2012. Effects of marsh periwinkle (Littoraria irrorata) size and density on cordgrass (Spartina aterniflora) biomass and dead standing material. Georgia Coastal Ecosystems LTER Data Catalog (data set INV-GCES-1211; http://gce-lter.marsci.uga.edu/public/app/dataset_details.asp?accession=INV-GCES-1211) B. Accession Number: INV-GCES-1211 C. Description 1. Originator(s): Name: Brian R. Silliman Address: 135 Duke Marine Lab Rd. Duke University Marine Lab Beaufort, North Carolina 28516-9721 Country: USA Email: brian.silliman@duke.edu 2. Abstract: Marsh periwinkles (Littoraria irrorata) are common in southeastern US salt marshes, including those on Sapelo Island, GA. They are known to affect the productivity of cordgrss (Spartina alterniflora) and also contribute to its decomposition following senescence. The population struture of Littoraria, in terms of the size and densities of individuals, varies widely in space and time. No previous experiments have, however, attempted to manipulate the density and body size of populations of Littoraria and assessd the response of Spartina. We perforned such an experiment in Airport Marsh on Sapelo Island, using small experimental enclosures and measured Spartina biomass and dead standing material after 3 months (mid July - mid Oct, 2012). We assessed response variables by removing all Spartina material from plots before seperating and drying them in the lab. 3. Study Type: Directed Study 4. Study Themes: Aquatic Invertebrate Ecology 5. LTER Core Areas: Other Site Research 6. Georeferences: none 7. Submission Date: Oct 30, 2012 D. Keywords: GCE, Georgia, Georgia Coastal Ecosystems, Littoraria, LTER, predation, salt marshes, Sapelo Island, Spartina, speciation, USA II. Research Origin Descriptors A. Overall Project Description 1. Project Title: Georgia Coastal Ecosystems LTER Project II 2. Principal Investigators: Name: Merryl Alber Address: Dept. of Marine Sciences University of Georgia Athens, Georgia 30602-3636 Country: USA Email: malber@uga.edu 3. Funding Period: May 01, 2006 to Jan 01, 2013 4. Objectives: To understand the mechanisms by which variation in the quality, source and amount of both fresh and salt water create temporal and spatial variability in estuarine habitats and processes, in order to predict directional changes that will occur in response to long-term shifts in estuarine salinity patterns 5. Abstract: The Georgia Coastal Ecosystems (GCE) LTER program, located on the central Georgia coast, was established in 2000. The study domain encompasses three adjacent sounds (Altamaha, Doboy, Sapelo) and includes upland (mainland, barrier islands, marsh hammocks), intertidal (fresh, brackish and salt marsh) and submerged (river, estuary, continental shelf) habitats. Patterns and processes in this complex landscape vary spatially within and between sites, and temporally on multiple scales (tidal, diurnal, seasonal, and interannual). Overlain on this spatial and temporal variation are long-term trends caused by climate change, sea level rise, and human alterations of the landscape. These long-term trends are likely to manifest in many ways, including changes in water quality, river discharge, runoff and tidal inundation patterns throughout the estuarine landscape. The overarching goal of the GCE program is to understand the mechanisms by which variation in the quality, source and amount of both fresh and salt water create temporal and spatial variability in estuarine habitats and processes, in order to predict directional changes that will occur in response to long-term shifts in estuarine salinity patterns. The objectives of the current funding cycle are 1) to continue to document long-term patterns of environmental forcing to the coastal zone, 2) to link environmental forcing to observed spatial and temporal patterns of biogeochemical processes, primary production, community dynamics, decomposition and disturbance, 3) to investigate the underlying mechanisms by which environmental gradients along the longitudinal (freshwater-saltwater) and 4) lateral (upland-subtidal) axes of estuaries drive ecosystem change, and 5) to explore the relative importance of larval transport and the conditions of the adult environment in determining community and genetic structure across both the longitudinal and vertical gradients of the estuary. To meet these objectives, we utilize a suite of approaches including long-term monitoring of abiotic drivers and ecosystem responses; manipulative and natural experiments designed to enable us to examine the importance of key ecosystem drivers; and modeling. 6. Funding Source: NSF OCE 0620959 B. Sub-project Description 1. Site Description a. Geographic Location: Coordinates: b. Physiographic Region: c. Landform Components: d. Hydrographic Characteristics: e. Topographic Attributes: f. Geology, Lithology and Soils: g. Vegetation Communities: h. History of Land Use and Disturbance: none recorded i. Climate: Climate summary for Sapelo Island, Georgia, based on NWS data from 1980-2010: Daily-aggregated Values: Mean (sample standard deviation) mean air temperature: 20.09°C (7.28°C) minimum air temperature: 15.02°C (7.96°C) maximum air temperature: 24.82°C (6.98°C) total precipitation: 3.26mm (10.3mm) Yearly-aggregated Daily Values: Mean (sample standard deviation) total precipitation (1980-2010): 1124mm (266mm) 2. Experimental or Sampling Design a. Design Characteristics: We factorially crossed snail size (2 levels: small [5-8mm shell height] and large [10-11mm shell-height]) and density (6 levels: zero; 35, 100, 150, 200, 300/enclosure) to asses the effects of these factors on Spartina. Each experiment treatment had 3 replicates, all maintained within 40cm x 40cm x 60cm (l x w x h) galvanized wire mesh cages (wooden framed). The mesh size was 2.5mm to prevent escape of the small and large snails. Cages were 0.16m^2, thus density treatments corresponded to zero, 219, 625, 938, 1250, 1875 per m^2. The lower 3 density levels were within the range observed for adult snails under non die-off conditions, while the upper 3 levels have only been observed during die-off conditions where snail fronts form. This experiment was done within the short Spartina zone at Airport marsh, Sapelo Island Georgia, where the Spartina canopy height was 25-50cm. Enclosures were arranged in a 6 x 6 grid, with all plot seperated by approx. 2m. The particular area was chosen for the relative homogeneity in Spartina height and sediment conditions. We assessed response variables at the end of the experiment by cutting and removing all Spartina, drying and weighing. b. Permanent Plots: Experimental cages were established in a 6 x 6 grid. Each plot was 40 x 40 x 60cm (I xw x h) and consited of a woodne frame to which 2.5mm galvamised wire mesh was stapled. Plots were accessed through the top of the cages, by simply removing the top of the cage and restapling to the frame after monitoring was complete. c. Data Collection Duration and Frequency: All sampling was done at the end of the experiment. We collected all aboveground Spartina (using hand shears), sperated into live (green) and dead (brown) components and dried at 70 degrees C until constant mass (about 3-4 days), before weighing. Beginning of Observations: Jul 13, 2012 End of Observations: Oct 15, 2012 3. Research Methods a. Field and Laboratory Methods: Method 1: Installation of cages -- Experimental cages were installed at the study site as described in 'Description' and 'Plots'. Method 2: Snail Collection -- Snails were collected by hand from the field on a single day. They were then sorted into size classes by hand in the lab. Small and large snails are just relative size classes and were selected with theoretical and logistical considerations, rather than to represent anything specific for Littoraria (this species shows continuous variation in sizes). Snails were then added to the established experimental enclosures in a single day (the day after collection - they were stored in cool conditions in the lab overnight). Snail densities were checked in the middle of the experiment and loss/mortality was found to be negligioble (<5% in all treatments). Snail densities were not assessed at the end of the experiment. Method 3: Spartina biomass -- At the end of the experiment, all Spartina (living and dead) was colleced from each plot, sorted into alive (green) and dead(non-green/brown) components, dried at 60 degrees Celcuis until reaching a stble mass and weighed. b. Instrumentation: Method 1: none Method 2: none Method 3: none c. Taxonomy and Systematics: Method 1: not applicable Method 2: not applicable Method 3: not applicable d. Speclies List: e. Permit History: Method 1: not applicable Method 2: not applicable Method 3: not applicable 4. Project Personnel a. Personnel: 1: Brian R. Silliman 2: John Griffin 3: Rebecca Atkins b. Affiliations: 1: Duke University, Beaufort, North Carolina 2: University of Swansea, Swansea 3: University of Floria III. Data Set Status and Accessibility A. Status 1. Latest Update: 02-Feb-2015 2. Latest Archive Date: 02-Feb-2015 3. Latest Metadata Update: 02-Feb-2015 4. Data Verification Status: Awaiting Revisions B. Accessibility 1. Storage Location and Medium: Stored at GCE-LTER Data Management Office Dept. of Marine Sciences Univ. of Georgia Athens, GA 30602-3636 USA on media: electronic data download (WWW) or compact disk 2. Contact Person: Name: Wade M. Sheldon, Jr. Address: Dept. of Marine Sciences University of Georgia Athens, Georgia 30602-3636 Country: USA Email: sheldon@uga.edu 3. Copyright Restrictions: not copyrighted 4. Restrictions: All publications based on this data set must cite the contributor and Georgia Coastal Ecosystems LTER project, and two copies of the manuscript must be submitted to the GCE-LTER Information Management Office. a. Release Date: Affiliates: Oct 30, 2012, Public: Oct 30, 2014 b. Citation: Data provided by the Georgia Coastal Ecosystems Long Term Ecological Research Project, supported by funds from NSF OCE 0620959 (data set INV-GCES-1211) c. Disclaimer: The user assumes all responsibility for errors in judgement based on interpretation of data and analyses presented in this data set. 5. Costs: free electronic data download via WWW, distribution on CD may be subject to nominal processing and handling fee IV. Data Structural Descriptors A. Data Set File 1. File Name: INV-GCES-1211_1_0.CSV 2. Size: 37 records 3. File Format: ASCII text (comma-separated value format) 3a. Delimiters: single comma 4. Header Information: 5 lines of ASCII text 5. Alphanumeric Attributes: 6. Quality Control Flag Codes: 7. Authentication Procedures: 8. Calculations: 9. Processing History: Software version: GCE Data Toolbox Version 3.8.0 (09-Nov-2013) Data structure version: GCE Data Structure 1.1 (29-Mar-2001) Original data file processed: INV-GCES-1211.txt (37 records) Data processing history: 02-Feb-2015: new GCE Data Structure 1.1 created ('newstruct') 02-Feb-2015: 37 rows imported from ASCII data file 'INV-GCES-1211.txt' ('imp_ascii') 02-Feb-2015: 82 metadata fields in file header parsed ('parse_header') 02-Feb-2015: data structure validated ('gce_valid') 02-Feb-2015: Q/C flagging criteria applied, 'flags' field updated ('dataflag') 02-Feb-2015: Name of column Snail density changed to Snail_density; Name of column Snail size changed to Snail_size; Name of column Aboveground Spartina biomass (g) changed to Aboveground_Spartina_biomass; Name of column Dead Spartina (g) changed to Dead_Spartin ('ui_editor') 02-Feb-2015: imported Dataset, Project, Site, Study, Status, Supplement metadata descriptors from the GCE Metabase ('imp_gcemetadata') 02-Feb-2015: updated 48 metadata fields in the Dataset, Project, Site, Status, Study, Supplement sections ('addmeta') 02-Feb-2015: flags for columns Snail_density, Aboveground_Spartina_biomass and Dead_Spartina converted to data columns, flag codes updated in metadata ('flags2cols') 02-Feb-2015: updated 6 metadata fields in the Data sections ('addmeta') 02-Feb-2015: updated 15 metadata fields in the Status, Data sections to reflect attribute metadata ('updatecols') 02-Feb-2015: parsed and formatted metadata ('listmeta') B. Variable Information 1. Variable Name: column 1. Plot column 2. Snail_density column 3. Flag_Snail_density column 4. Snail_size column 5. Aboveground_Spartina_biomass column 6. Flag_Aboveground_Spartina_biomass column 7. Dead_Spartina column 8. Flag_Dead_Spartina 2. Variable Definition: column 1. Unique idetifyer for each experimental plot column 2. Snail density experimental set at beginning of experiment column 3. QA/QC flags for Snail density experimental set at beginning of experiment (flagging criteria, where "x" is Snail_density: x<0="I") column 4. Experimentally set at beginning of experiment (S = small [5-8mm shell height], L = large [10-11mm]). column 5. Total mass of living Spartina from each plot (after drying) column 6. QA/QC flags for Total mass of living Spartina from each plot (after drying) (flagging criteria, where "x" is Aboveground_Spartina_biomass: x<0="I", x>40="Q") column 7. Total mass of dead Spartina from each plot (after drying) column 8. QA/QC flags for Total mass of dead Spartina from each plot (after drying) (flagging criteria, where "x" is Dead_Spartina: x<0="I", x>40="Q") 3. Units of Measurement: column 1. none column 2. none column 3. none column 4. none column 5. grams column 6. none column 7. grams column 8. none 4. Data Type a. Storage Type: column 1. integer column 2. integer column 3. string column 4. string column 5. floating-point column 6. string column 7. floating-point column 8. string b. Variable Codes: Snail size: S = Small, L = Large, NA = Not Applicable c. Numeric Range: column 1. 1 to 40 column 2. 0 to 300 column 3. (none) column 4. (none) column 5. 3.78 to 34.62 column 6. (none) column 7. 3.09 to 22.02 column 8. (none) d. Missing Value Code: 5. Data Format a. Column Type: column 1. numerical column 2. numerical column 3. text column 4. text column 5. numerical column 6. text column 7. numerical column 8. text b. Number of Columns: 8 c. Decimal Places: column 1. 0 column 2. 0 column 3. 0 column 4. 0 column 5. 2 column 6. 0 column 7. 2 column 8. 0 6. Logical Variable Type: column 1. nominal (discrete) column 2. data (discrete) column 3. coded value (none) column 4. free text (none) column 5. data (continuous) column 6. coded value (none) column 7. data (continuous) column 8. coded value (none) 7. Flagging Criteria: column 1. x<0="I" column 2. x<0="I" column 3. none column 4. none column 5. x<0="I";x>40="Q" column 6. none column 7. x<0="I";x>40="Q" column 8. none C. Data Anomalies: V. Supplemental Descriptors A. Data Acquisition 1. Data Forms: Field notebooks 2. Form Location: In care of Rebecca Atkins, PhD student at University of Georgia 3. Data Entry Validation: NA B. Quality Assurance/Quality Control Procedures: C. Supplemental Materials: NA D. Computer Programs: Microsoft Excel E. Archival Practices: F. Publications: not specified G. History of Data Set Usage 1. Data Request History: not specified 2. Data Set Update History: none 3. Review History: none 4. Questions and Comments from Users: none