I. Data Set Descriptors A. Title: Steven C. Pennings. 2025. Borrichia removal experiment at Dean Creek marsh on Sapelo Island, Georgia between 1995 and 2001. Georgia Coastal Ecosystems LTER Data Catalog (data set PLT-GCED-2510; /data/PLT-GCED-2510) B. Accession Number: PLT-GCED-2510 C. Description 1. Originator(s): Name: Steven C. Pennings Address: Department of Biology and Biochemistry University of Houston Houston, Texas 77204-5513 Country: USA Email: scpennin@central.uh.edu 2. Abstract: To examine the effect of Borrichia on Batis and Sarcocornia sp., I completely clipped all vegetation from six 0.5 x 0.5 m quadrats in a mixed stand of the three species at the Dean Creek marsh in June 1995. Six additional plots were left unmanipulated as controls. Removal and control plots were fully interspersed. I clipped Borrichia from the removal plots every 6 months but allowed other plant species to re-colonize. 3. Study Type: Directed Study 4. Study Themes: Plant Ecology, Marsh Ecology 5. LTER Core Areas: Primary Production 6. Georeferences: none 7. Submission Date: Nov 11, 2025 D. Keywords: Batis, Borrichia, GCE, Georgia, Georgia Coastal Ecosystems, LTER, marshes, plant biomass, plant community, plants, Primary Production, Sapelo Island, Sarcocornia, USA II. Research Origin Descriptors A. Overall Project Description 1. Project Title: Georgia Coastal Ecosystems LTER Project 2. Principal Investigators: Name: James T. Hollibaugh Address: Dept. of Marine Sciences University of Georgia Athens, Georgia 30602-3636 Country: USA Email: aquadoc@uga.edu 3. Funding Period: May 01, 2000 to May 01, 2006 4. Objectives: To investigate the linkages between coastal and distant upland areas in central Georgia mediated by surface and ground water delivery to the coastal zone. This will be addressed by examining the relationship between variability in environmental factors driven by river flow, primarily salinity, and ecosystem processes and structure. 5. Abstract: We propose to establish a Long Term Ecological Research site on the central Georgia coast in the vicinity of Sapelo Island. This is a barrier island and marsh complex with the Altamaha River, one of the largest and least developed rivers on the east coast of the US, as the primary source of fresh water. The proposed study would investigate the linkages between local and distant upland areas mediated by water - surface water and ground water - delivery to the coastal zone. We would explicitly examine the relationship between variability in environmental factors driven by river flow, primarily salinity because we can measure it at high frequency, and ecosystem processes and structure. We will accomplish this by comparing estuary/marsh complexes separated from the Altamaha River by one or two lagoonal estuary/marsh complexes that damp and attenuate the river signal. This spatial gradient is analogous to the temporal trend in riverine influence expected as a result of development in the watershed. We will implement a monitoring system that documents physical and biological variables and use the time trends and spatial distributions of these variables and of their variance structure to address questions about the factors controlling distributions, trophic structure, diversity, and biogeochemistry. An existing GIS-based hydrologic model will be modified to incorporate changes in river water resulting from changes in land use patterns that can be expected as the watershed develops. This model will be linked to ecosystem models and will serve as an heuristic and management tool. Another consequence of coastal development is that as river flow decreases, groundwater flow increases and becomes nutrified. We will compare the effects of ground water discharge from the surficial aquifer in relatively pristine (Sapelo Island) versus more urbanized (mainland) sites to assess the relative importance of fresh water versus nutrients to productivity, structure and biomass turnover rate in marshes influenced by groundwater. We will also investigate the effect of marine processes (tides, storm surge) on mixing across the fresh/salt interface in the surficial aquifer. Additional physical studies will relate the morphology of salt marsh - tidal creek channel complexes to tidal current distributions and exchange. These findings will be incorporated into a physical model that will be coupled to an existing ecosystem model. The land/ocean margin ecosystem lies at the interface between two ecosystems in which distinctly different groups of decomposers control organic matter degradation. The terrestrial ecosystem is largely dominated by fungal decomposers, while bacterial decomposers dominate the marine ecosystem. Both groups are important in salt marsh-dominated ecosystems. Specific studies will examine, at the level of individual cells and hyphae, the relationship bacteria and fungi in the consortia that decompose standing dead Spartina and other marsh plants and examine how, or if, this changes along the salinity gradient. 6. Funding Source: NSF OCE 9982133 B. Sub-project Description 1. Site Description a. Geographic Location: GCE6 -- Dean Creek, Sapelo Island, Georgia, USA Coordinates: GCE6 -- NW: 081 17 58.28 W, 31 23 38.66 N NE: 081 15 51.76 W, 31 23 38.66 N SE: 081 15 51.76 W, 31 22 15.61 N SW: 081 17 58.28 W, 31 22 15.61 N b. Physiographic Region: GCE6 -- Barrier island c. Landform Components: GCE6 -- Intertidal salt marsh, sand beach, maritime forest d. Hydrographic Characteristics: GCE6 -- Site contains Dean Creek and borders Doboy Sound, and is subject to 2-3m semi-diurnal tides e. Topographic Attributes: GCE6 -- Flat, with elevations ranging from 0-3m above mean low tide f. Geology, Lithology and Soils: GCE6 -- unspecified g. Vegetation Communities: GCE6 -- Vegetation is mostly short and tall Spartina alterniflora, with small amounts of Juncus and Borrichia. h. History of Land Use and Disturbance: GCE6 -- Oct 01, 2000: Permanent plots were established in two nominal marsh zones based on marsh structure -- creek zone and high marsh -- and eight plots were randomly located in each zone and marked with stakes 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: To examine the effect of Borrichia on Batis and Sarcocornia sp., I completely clipped all vegetation from six 0.5 x 0.5 m quadrats in a mixed stand of the three species at the Dean Creek marsh in June 1995. Six additional plots were left unmanipulated as controls. Removal and control plots were fully interspersed. I clipped Borrichia from the removal plots every 6 months but allowed other plant species to re-colonize. b. Permanent Plots: 0.5 by 0.5 m permanent plots c. Data Collection Duration and Frequency: Every six months I measured percent cover of Borrichia, Batis and Sarcocornia sp. in the plots using a 0.5 m x 0.5 m quadrat divided into 100 cells. I scored each species as present or absent in each cell of the quadrat. Borrichia that had invaded the removal treatment during the past six months was sampled before it was removed by clipping with a hand clippers. Beginning of Observations: Oct 16, 1995 End of Observations: Aug 16, 2001 3. Research Methods a. Field and Laboratory Methods: Measurement -- Every six months I measured percent cover of Borrichia, Batis and Sarcocornia sp. in the plots using a 0.5 m x 0.5 m quadrat divided into 100 cells. I scored each species as present or absent in each cell of the quadrat. Spartina alterniflora was briefly present in one of the 12 plots (data not included in dataset) but otherwise no other species were present. b. Protocols: none c. Instrumentation: none d. Taxonomy and Systematics: e. Speclies List: f. Permit History: none 4. Project Personnel a. Personnel: Steven C. Pennings b. Affiliations: University of Houston, Houston, Texas III. Data Set Status and Accessibility A. Status 1. Latest Update: 11-Nov-2025 2. Latest Archive Date: 11-Nov-2025 3. Latest Metadata Update: 11-Nov-2025 4. Data Verification Status: Reviewed by IM 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: 130 Marine Sciences Marine Sciences Building Athens, Georgia 30602-3636 Country: USA Email: sheldon@uga.edu 3. Copyright Restrictions: not copyrighted 4. Restrictions: This information is licensed under a Creative Commons Attribution 4.0 International License (see: https://creativecommons.org/licenses/by/4.0/). The consumer of these data ("Data User" herein) has an ethical obligation to cite it appropriately in any publication that results from its use. The Data User should realize that these data may be actively used by others for ongoing research and that coordination may be necessary to prevent duplicate publication. The Data User is urged to contact the authors of these data if any questions about methodology or results occur. Where appropriate, the Data User is encouraged to consider collaboration or co-authorship with the authors. The Data User should realize that misinterpretation of data may occur if used out of context of the original study. While substantial efforts are made to ensure the accuracy of data and associated documentation, complete accuracy of data sets cannot be guaranteed. All data are made available "as is." The Data User should be aware, however, that data are updated periodically and it is the responsibility of the Data User to check for new versions of the data. The data authors and the repository where these data were obtained shall not be liable for damages resulting from any use or misinterpretation of the data. a. Release Date: Affiliates: Nov 11, 2025, Public: Nov 11, 2027 b. Citation: Data provided by the Georgia Coastal Ecosystems Long Term Ecological Research Project, supported by funds from NSF OCE 9982133 (data set PLT-GCED-2510) 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: PLT-GCED-2510_1_0.CSV 2. Size: 144 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: Q = questionable value, I = invalid value, E = estimated value 7. Authentication Procedures: 8. Calculations: 9. Processing History: Software version: GCE Data Toolbox Version 3.9.10 (23-May-2022) Data structure version: GCE Data Structure 1.1 (29-Mar-2001) Original data file processed: PLT-GCED-2510.txt (144 records) Data processing history: 11-Nov-2025: new GCE Data Structure 1.1 created ('newstruct') 11-Nov-2025: 144 rows imported from ASCII data file 'PLT-GCED-2510.txt' ('imp_ascii') 11-Nov-2025: 83 metadata fields in file header parsed ('parse_header') 11-Nov-2025: data structure validated ('gce_valid') 11-Nov-2025: Q/C flagging criteria applied, 'flags' field updated ('dataflag') 11-Nov-2025: automatically assigned study date metadata descriptors based on the range of date values in date/time columns (add_studydates) 11-Nov-2025: updated 1 metadata fields in the Dataset section(s) ('addmeta') 11-Nov-2025: updated 1 metadata fields in the Dataset section(s) ('addmeta') 11-Nov-2025: updated 1 metadata fields in the Dataset section(s) ('addmeta') 11-Nov-2025: imported Dataset, Project, Site, Study, Status, Supplement metadata descriptors from the GCE Metabase ('imp_gcemetadata') 11-Nov-2025: updated 56 metadata fields in the Dataset, Project, Site, Status, Study, Supplement section(s) ('addmeta') 11-Nov-2025: updated 6 metadata fields in the Data section(s) ('addmeta') 11-Nov-2025: updated 15 metadata fields in the Status, Data sections to reflect attribute metadata ('updatecols') 11-Nov-2025: parsed and formatted metadata ('listmeta') B. Variable Information 1. Variable Name: column 1. Day column 2. Month column 3. Year column 4. Treatment column 5. Borrichia_percent column 6. Batis_percent column 7. Sarcocornia_percent 2. Variable Definition: column 1. Day of the month column 2. Month of the year column 3. Calendar year column 4. Experimental treatment column 5. Percent cover of Borrichia fructescens column 6. Percent cover of Batis maritima column 7. Percent cover of perennial formerly know as Salicornia virginica 3. Units of Measurement: column 1. D column 2. M column 3. YYYY column 4. none column 5. percent column 6. percent column 7. percent 4. Data Type a. Storage Type: column 1. integer column 2. integer column 3. integer column 4. string column 5. floating-point column 6. floating-point column 7. floating-point b. Variable Codes: c. Numeric Range: column 1. 2 to 21 column 2. 2 to 10 column 3. 1995 to 2001 column 4. (none) column 5. 0 to 100 column 6. 0 to 100 column 7. 0 to 100 d. Missing Value Code: 5. Data Format a. Column Type: column 1. numerical column 2. numerical column 3. numerical column 4. text column 5. numerical column 6. numerical column 7. numerical b. Number of Columns: 7 c. Decimal Places: column 1. 0 column 2. 0 column 3. 0 column 4. 0 column 5. 0 column 6. 0 column 7. 0 6. Logical Variable Type: column 1. datetime (discrete) column 2. datetime (discrete) column 3. datetime (discrete) column 4. free text (none) column 5. data (continuous) column 6. data (continuous) column 7. data (continuous) 7. Flagging Criteria: column 1. x<1="I";x>31="I";x<1="Q";x>31="Q" column 2. x<1="I";x>12="I";x<1="Q";x>12="Q" column 3. x<1995="I";x>2001="I";x<1995="Q";x>2001="Q" column 4. none column 5. x<0="I";x>100="I";x<0="Q";x>100="Q" column 6. x<0="I";x>100="I";x<0="Q";x>100="Q" column 7. x<0="I";x>100="I";x<0="Q";x>100="Q" C. Data Anomalies: Data from August 2000 are missing, or perhaps plots were not sampled on that date. At this time (October 2025) I can't remember. Spartina alterniflora was briefly present in one of the 12 plots (data not included in dataset) but otherwise no other species were present. V. Supplemental Descriptors A. Data Acquisition 1. Data Forms: Paper data sheets 2. Form Location: Office of Steven Pennings, but also scanned and online at GCE web site 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