I. Data Set Descriptors A. Title: Brian R. Silliman. 2011. Effects of the relative abundance of predatory mud crabs (Panopeus obesus and Eurytium limosum) on abundances of snails and fiddler crabs in a Georgia salt marsh. Georgia Coastal Ecosystems LTER Data Catalog (data set INV-GCES-1110; http://gce-lter.marsci.uga.edu/public/app/dataset_details.asp?accession=INV-GCES-1110) B. Accession Number: INV-GCES-1110 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: Predatory mud crabs (Panopeus obesus and Eurytium limosum) are two of the main resident infaunal predators in southeastern US salt marshes. Little is known, however, about their effects on important prey species. These influences are llikely to be dependent on the identity and relative abundances of the two predator species. We therefore manipulated the relative abundances of Panopeus and Eurytium in experimental cages in the field (at Airport Marsh, Sapelo Island, GA). We maintained the treatments over 4 months (July - October 2011), before assessing impacts on predator limb loss (an indicator of interspecific antagonism) and prey densitities (small and large mud fiddler crabs and marsh periwinkles). 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 15, 2011 D. Keywords: Eurytium, GCE, Georgia, Georgia Coastal Ecosystems, Littoraria, LTER, Panopeus, predation, salt marshes, Sapelo Island, speciation, Uca, 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 included 10 treatments containing predator crabs, each with 10 individuals consisting of (P = Panopues obesus, E = Eurytium limosum): 0P + 10E; 1P + 9E; 2P + 8E.... 10P + 0E; we also included a predator-free control, which was exactly the same as the other enclosures but contained no predatory mud crabs. Each experimental treatment had 4 replicates (except for 10E, which was reduced to 3 replicates because of cage breakage); all replicates were maintained within 200cm x 100cm x 100cm (l x w x h) galvanized wire mesh cages (with 8mm mesh size). We added 1500 Littoraria (a naturally-occuring high density) to each enclosure at the start of the experiment; Uca densities were meaured but not standardised at the start due to logistical constraints; Predatory crab treatments (densities) were maintained (dead, missing and crabs grown out of size class replaced) every approx. 17 days during the experiment. Predator and prey responses were measured in the field after 4 months. b. Permanent Plots: Experimental plots ('enclosures' or 'cages') were 2 x 1 x 1m (l x w x h) enclosures with wooden frames and covered in galvanised wire mesh (8mm mesh size). They had a top and extended 30cm into the ground to prevent escape of burrowing mud crabs. Small fiddler crabs and juvenille snails could pass through cages due to the mesh size, but adult fiddler crabs snails or the manipulted predatory crabs could not. These plots were located within the short/intermediate height Spartina zone at the experimental site. c. Data Collection Duration and Frequency: Sampling of prey densities and condition of predators was conducted at the end of the experiment. Beginning of Observations: Jul 01, 2011 End of Observations: Oct 01, 2011 3. Research Methods a. Field and Laboratory Methods: Method 1: Predatory mud crabs -- plots were searched and cleared of all pre-existing predatory mud crabs at the begnning of the experiment and establishment of the experimental treatments. Mud crabs for the treatments were collected by hand from burrows in Airport marsh. Only crabs of carapace diameter of 32-36mm and those with a complete set of limbs were used in the experiment. Crabs added to the experiment to replace daed crabs within the last month of the experiment were marked and excluded from analyses of limb loss to avoid confounding limb loss and mortality. Method 2: Prey -- densities of both focal prey species were estimated at the end of the expeirment. Mud fiddler crab (Uca pugnax) density was estimated based on a visual count of burrows within two replicate 20 x 20 quadrats in each plot; all marsh periwinkles (Littoraria irrorata) were removedby hand and counted; limb loss was based on summed loss of limbs for each species within each cage at the end of the experimen -- predatory crabs were removed from cages and their degree of limb loss evaluated. b. Instrumentation: Method 1: none Method 2: none c. Taxonomy and Systematics: Method 1: not applicable Method 2: not applicable d. Speclies List: e. Permit History: Method 1: not applicable Method 2: not applicable 4. Project Personnel a. Personnel: 1: Brian R. Silliman 2: John Griffin b. Affiliations: 1: Duke University, Beaufort, North Carolina 2: University of Swansea, Swansea III. Data Set Status and Accessibility A. Status 1. Latest Update: 06-Feb-2015 2. Latest Archive Date: 02-Feb-2015 3. Latest Metadata Update: 06-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 15, 2011, Public: Oct 15, 2013 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-1110) 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-1110_1_2.CSV 2. Size: 43 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 3.9.2 (01-Dec-2014) Data structure version: GCE Data Structure 1.1 (29-Mar-2001) Original data file processed: INV-GCES-1110.txt (43 records) Data processing history: 02-Feb-2015: new GCE Data Structure 1.1 created ('newstruct') 02-Feb-2015: 43 rows imported from ASCII data file 'INV-GCES-1110.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 Fiddlers (small) changed to Fiddlers_small; Name of column Fiddlers (large) changed to Fiddlers_large; Name of column Panopeus limbs missing changed to Panopeus_limbs_missing; Name of column Eurytium limbs missing changed to Eurytium_limbs_missin ('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: manually edited data set metadata ('ui_editmetadata') 02-Feb-2015: Numeric Type of column Fiddlers_small changed from 'continuious' to 'continuous'; Numeric Type of column Fiddlers_large changed from 'continuious' to 'continuous'; Numeric Type of column Panopeus_limbs_missing changed from 'continuious' to 'continuous'; Numeric Type of column Eurytium_limbs_missing changed from 'continuious' to 'continuous ('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') 06-Feb-2015: Units of column Panopeus_limbs_missing changed from 'none' to 'ratio'; Units of column Eurytium_limbs_missing changed from 'none' to 'ratio ('ui_editor') 06-Feb-2015: flags for columns Snails, Fiddlers_small, Fiddlers_large, Panopeus_limbs_missing and Eurytium_limbs_missing converted to data columns, flag codes updated in metadata ('flags2cols') 06-Feb-2015: updated 6 metadata fields in the Data sections ('addmeta') 06-Feb-2015: updated 15 metadata fields in the Status, Data sections to reflect attribute metadata ('updatecols') 06-Feb-2015: parsed and formatted metadata ('listmeta') B. Variable Information 1. Variable Name: column 1. Plot column 2. Treatment column 3. Snails column 4. Flag_Snails column 5. Fiddlers_small column 6. Flag_Fiddlers_small column 7. Fiddlers_large column 8. Flag_Fiddlers_large column 9. Panopeus_limbs_missing column 10. Flag_Panopeus_limbs_missing column 11. Eurytium_limbs_missing column 12. Flag_Eurytium_limbs_missing 2. Variable Definition: column 1. Unique number given to each experimental plot in the field column 2. Relative abundances of Panopeus: Euytium column 3. Final density of snails per cage (Littoraria irrorata); initial was 1500 column 4. QA/QC flags for Final density of snails per cage (Littoraria irrorata); initial was 1500 (flagging criteria, where "x" is Snails: x<0="I", x>1500="Q") column 5. Final density of small fiddler crabs (Uca pugnax; holes <8mm diam.) (initial density natural, approx. 3). Average from 2, 30 x 30cm quadrats/plot. column 6. QA/QC flags for Final density of small fiddler crabs (Uca pugnax; holes <8mm diam.) (initial density natural, approx. 3). Average from 2, 30 x 30cm quadrats/plot. (flagging criteria, where "x" is Fiddlers_small: x<0="I", x>20="Q") column 7. Final density of large fiddler crabs (Uca pugnax; holes >8mm diam.) (initial density natural, approx. 8). Average from 2, 30 x 30cm quadrats/plot. column 8. QA/QC flags for Final density of large fiddler crabs (Uca pugnax; holes >8mm diam.) (initial density natural, approx. 8). Average from 2, 30 x 30cm quadrats/plot. (flagging criteria, where "x" is Fiddlers_large: x<0="I", x>30="Q") column 9. Average number of missing limbs per Panopeus individual at end of experiment column 10. QA/QC flags for Average number of missing limbs per Panopeus individual at end of experiment (flagging criteria, where "x" is Panopeus_limbs_missing: x<0="I", x>10="Q") column 11. Average number of missing limbs per Eurytium individual at end of experiment column 12. QA/QC flags for Average number of missing limbs per Eurytium individual at end of experiment (flagging criteria, where "x" is Eurytium_limbs_missing: x<0="I", x>10="Q") 3. Units of Measurement: column 1. none column 2. none column 3. count column 4. none column 5. count column 6. none column 7. count column 8. none column 9. ratio column 10. none column 11. ratio column 12. none 4. Data Type a. Storage Type: column 1. integer column 2. string column 3. integer column 4. string column 5. floating-point column 6. string column 7. floating-point column 8. string column 9. floating-point column 10. string column 11. floating-point column 12. string b. Variable Codes: c. Numeric Range: column 1. 3 to 48 column 2. (none) column 3. 291 to 743 column 4. (none) column 5. 2.5 to 19.5 column 6. (none) column 7. 5 to 30 column 8. (none) column 9. 0 to 3 column 10. (none) column 11. 0 to 6.5 column 12. (none) d. Missing Value Code: 5. Data Format a. Column Type: column 1. numerical column 2. text column 3. numerical column 4. text column 5. numerical column 6. text column 7. numerical column 8. text column 9. numerical column 10. text column 11. numerical column 12. text b. Number of Columns: 12 c. Decimal Places: column 1. 0 column 2. 0 column 3. 0 column 4. 0 column 5. 0 column 6. 0 column 7. 0 column 8. 0 column 9. 0 column 10. 0 column 11. 0 column 12. 0 6. Logical Variable Type: column 1. nominal (discrete) column 2. free text (none) column 3. data (discrete) column 4. coded value (none) column 5. calculation (continuous) column 6. coded value (none) column 7. calculation (continuous) column 8. coded value (none) column 9. calculation (continuous) column 10. coded value (none) column 11. calculation (continuous) column 12. coded value (none) 7. Flagging Criteria: column 1. none column 2. none column 3. x<0="I";x>1500="Q" column 4. none column 5. x<0="I";x>20="Q" column 6. none column 7. x<0="I";x>30="Q" column 8. none column 9. x<0="I";x>10="Q" column 10. none column 11. x<0="I";x>10="Q" column 12. none C. Data Anomalies: V. Supplemental Descriptors A. Data Acquisition 1. Data Forms: 2. Form Location: 3. Data Entry Validation: B. Quality Assurance/Quality Control Procedures: C. Supplemental Materials: D. Computer Programs: 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