GCE-LTER Altamaha River plant community monitoring Dr. Steven C. Pennings University of Houston

Department of Biology and Biochemistry University of Houston Houston Texas 77204-5513 USA

scpennin@central.uh.edu https://uh.edu/nsm/biology-biochemistry/people/profiles/steven-pennings/ https://orcid.org/0000-0003-4757-7125 Georgia Coastal Ecosystems LTER Project

Dept. of Marine Sciences University of Georgia Athens Georgia 30602-3636 USA

gcelter@uga.edu https://gce-lter.marsci.uga.edu/ Dr. Steven C. Pennings University of Houston

Department of Biology and Biochemistry University of Houston Houston Texas 77204-5513 USA

scpennin@central.uh.edu https://uh.edu/nsm/biology-biochemistry/people/profiles/steven-pennings/ https://orcid.org/0000-0003-4757-7125 Principal investigator 2026

We will monitor plant biomass and composition at three sites on the Altamaha River to test the hypothesis that end-of-year biomass and community composition varies as a function of freshwater discharge from the Altamaha, local rainfall, and average sea level. Two sites are located to capture the transition from Zizaniopsis to Spartina cynosuroides in areas with very low water column salinity, and one site is located to capture the transition from Spartina cynosuroides to S. alterniflora in areas with brackish waters. We also observe wrack disturbance in these plots to estimate disturbance rates in different habitats.

Area 2: Patterns within the Domain (more information)

marsh population density population diversity LTER NSF GCE plants Spartina Zizaniopsis disturbance patterns plant ecology population ecology population studies primary production Overall geographic extent of the research project -81.582311 -81.237936 31.401403 31.296034 2012-10-01

Core monitoring activity of GCE-LTER, $5,880,000

estuary marsh complex Altamaha River - Altamaha River transect used for GCE quarterly hydrographic monitoring surveys. Nominal profiling stations are defined every 2km from -4km to 40km (relative to station 0km at the line of demarcation), based on an estimated Thalweg line running up the main river channel. -81.582311 -81.237936 31.401403 31.296034 GPS data file (Trimble, Excel) https://gce-lter.marsci.uga.edu/private/registration/files/gps_data/GCE-35-2012_GPS_Altamaha_River_Plant_Community_Monitoring_sites.kml

one site upstream from two-way fish camp, one site upstream of the champney boat ramp, and one site downstream of GCE 8.

PVC pipe or wooden stakes will be used to mark the corners of permanent plots, 0.5 x 0.5 m in size. Eight plots will be installed in creekbank vegetation at each site, for a total of 24 plots. Stakes will be removed by Pennings if the long-term monitoring program is ended.

PLT-GCEM-2511c - GCE-LTER Altamaha River Plant Community Monitoring Survey in October 2025 https://gce-lter.marsci.uga.edu/public/app/dataset_details.asp?id=870 PLT-GCES-1609c - Long-term Plant Biomass Monitoring Data from Altamaha River Plant Transition Sites near the Georgia Coastal Ecosystems LTER Project on Sapelo Island, Georgia https://gce-lter.marsci.uga.edu/public/app/dataset_details.asp?id=759 PLT-GCEM-2311c - GCE-LTER Altamaha River Plant Community Monitoring Survey in October 2023 https://gce-lter.marsci.uga.edu/public/app/dataset_details.asp?id=812 PLT-GCEM-2411c - GCE-LTER Altamaha River Plant Community Monitoring Survey in October 2024 https://gce-lter.marsci.uga.edu/public/app/dataset_details.asp?id=847 PLT-GCEM-2211c - GCE-LTER Altamaha River Plant Community Monitoring Survey in October 2022 https://gce-lter.marsci.uga.edu/public/app/dataset_details.asp?id=796 PLT-GCEM-2111c - GCE-LTER Altamaha River Plant Community Monitoring Survey in October 2021 https://gce-lter.marsci.uga.edu/public/app/dataset_details.asp?id=774 PLT-GCEM-2011c - GCE-LTER Altamaha River Plant Community Monitoring Survey in October 2020 https://gce-lter.marsci.uga.edu/public/app/dataset_details.asp?id=735 PLT-GCEM-1911c - GCE-LTER Altamaha River Plant Community Monitoring Survey in October 2019 https://gce-lter.marsci.uga.edu/public/app/dataset_details.asp?id=734 PLT-GCEM-1811c - GCE-LTER Altamaha River Plant Community Monitoring Survey in October 2018 https://gce-lter.marsci.uga.edu/public/app/dataset_details.asp?id=685 PLT-GCEM-1711c - GCE-LTER Altamaha River Plant Community Monitoring Survey in October 2017 https://gce-lter.marsci.uga.edu/public/app/dataset_details.asp?id=636 PLT-GCEM-1611c - GCE-LTER Altamaha River Plant Community Monitoring Survey in October 2016 https://gce-lter.marsci.uga.edu/public/app/dataset_details.asp?id=634 PLT-GCEM-1511c - GCE-LTER Altamaha River Plant Community Monitoring Survey in October 2015 https://gce-lter.marsci.uga.edu/public/app/dataset_details.asp?id=576 PLT-GCEM-1412c - GCE-LTER Altamaha River Plant Community Monitoring Survey in October 2014 https://gce-lter.marsci.uga.edu/public/app/dataset_details.asp?id=479 PLT-GCEM-1312 - GCE-LTER Altamaha River Plant Community Monitoring Survey in October 2013 https://gce-lter.marsci.uga.edu/public/app/dataset_details.asp?id=478 PLT-GCEM-1210 - GCE-LTER Altamaha River Plant Community Monitoring Survey in October 2012 https://gce-lter.marsci.uga.edu/public/app/dataset_details.asp?id=431