Marsh transplant experiments 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 2007-01-01 2009-12-31 Hongyu Guo University of Houston

Department of Biology and Biochemistry 369 Science and Research Bldg 2 University of Houston Houston Texas 77204-5001 USA

greatuniverse@hotmail.com Graduate research assistant 2007-01-01 2009-12-31 2026

Results from 2007 (Spartina alterniflora, Juncus roemerianus and Zizaniopsis miliacea) and 2008 (Batis maritima, Schoenoplectus americanus and Pontederia cordata) indicated that the freshwater plants were excluded from saltier sites by physical stress (they died with or without neighbors, indicated in figures by "N/A"), and that the intensity of competition increased at less-saline sites, excluding salt marsh species. There were hints of facilitation of some plant species by background vegetation (positive values of RII) at the saltiest sites. The third set of transplants in 2009 are currently underway and appear to show similar results.

H. Guo (Ph.D. student, UH) and S. Pennings (UH) are conducting a series of transplant experiments to explain patterns of vegetation composition, diversity and productivity (see Question 3) in the GCE domain. Over the years 2007, 2008 and 2009, Guo transplanted three saltmarsh plants, Spartina alterniflora, Batis maritima and Salicornia virginica, three brackish marsh plants, Juncus roemerianus, Spartina cynosuroides, and Schoenoplectus americanus, and three fresh marsh plants, Pontederia cordata, Zizaniopsis milacea and an unidentified species, to replicate fresh, brackish and saline sites, with and without competition. Plants were transplanted in March of each year, and harvested, dried and weighed in October of each year, after 7 months of growth. Sites were categorized into 5 regions of salinity (fresh, brackish, low-salinity salt, medium-salinity salt, and high-salinity salt) based on GCE water column monitoring and porewater salinity data collected by Guo. The strength of competition among transplanted plants and background vegetation was calculated for each salinity zone as RII, Relative Interaction Intensity, or (Biomass with neighbor - Biomass without neighbor)/(Biomass with neighbor + Biomass without neighbor).

Question 5: What is the relative importance of larval transport versus the conditions of the adult environment in determining community and genetic structure across both the longitudinal and lateral gradients of the estuarine landscape? (more information)

LTER NSF GCE Batis Juncus Pontederia Salicornia Schoenoplectus Spartina Zizaniopsis Georgia salt marsh transplant Overall geographic extent of the research project -81.493498 -81.195661 31.552554 31.304063 2007-01-01 2009-12-31

National Science Foundation grant number OCE-0620959

estuary marsh complex Eulonia - Transitional salt marsh/upland forest site at the upper reach of the Sapelo River near Eulonia, Georgia. The main marsh area is to the north of the channel where the upland is controlled by DNR. Several small creeks lie within the study area. Residential development is increasing on the upland areas south of the channel. A hydrographic sonde is deployed within this site attached to a private dock to the south of the main channel near the HW-17 bridge. The sonde is accessed from a dock on a private residence off of highway 17. As of late 2017 the property is owned by Linda Hornby. She asks that we notify her by text about an hour before arriving to service the sondes. There is no reason to go to this property other than for sonde work. -81.428481 -81.410732 31.546750 31.533963 Hunt Camp - Barrier island/marsh site on western Sapelo Island. This site is located at the upper reaches of the Duplin River, and is within the Sapelo Island National Estuarine Research Reserve. Existing well fields border small marsh area to northwest, some wells have been installed to south end of hammock where marsh is more extensive and permanent plots are located. Two existing hydrographic sondes and weather stations within this site are operated by SINERR (Hunt Camp dock) and UGAMI (flume dock). -81.295506 -81.258908 31.497026 31.462320 Four Mile Island - Low salt marsh/estuary site encompassing the southwestern end of Four Mile Island and the Sapelo River near Sapelo Sound. The large island is totally marsh, with no upland, and no development. Nearby areas, like "Sutherland Bluff", are developing with golf courses. A hydrographic sonde is deployed within this site attached to channel marker 4 (under U.S. Coast Guard permit). Salinity regime is similar to seawater. -81.318961 -81.292844 31.552554 31.533604 North Sapelo - High salinity marsh/Sapelo Sound site. Few or no small creeks, but one large creek is easily accessed. Further upstream upland drainage is affected by culvert at Reynolds' duck pond. Upland is heavily forested. Hydrographic sonde is deployed adjacent to this site attached to a channel marker (under U.S. Coast Guard permit). A huge mud flat is present at the northern tip of Sapelo Island. -81.233249 -81.195661 31.546868 31.515188 Meridian - Inland marsh and tidal creek site near Meridian, Georgia. The primary marsh site is to the south of the dock in front of the Sapelo Island Visitor Center. Some small creeks and one large creek (Hudson Creek) are present. Upland is heavily forested. Marsh to the north of the dock can be used for additional studies if larger areas are required. Upland to the North is being developed for residential use, so future access is uncertain. The USGS super station site (weather station plus multiple-sensor sonde) is deployed off the ferry dock. Salinity is similar to seawater because there is little freshwater input from the upland. -81.370752 -81.357256 31.463533 31.448419 Folly River - Salt marsh/tidal creek site at the Folly River near Doboy Sound. No upland areas present. The north side of Doboy Sound immediately opposite is similar, but creeks are not as nice. No existing markers are close enough for sonde deployment, so we will initially use the existing sonde at Marsh Landing operated by UGAMI for surrogate hydrographic data. -81.354413 -81.327201 31.442538 31.417640 Dean Creek - Doboy Sound/salt marsh site at the southern end of Sapelo Island near Dean Creek and the Sapelo lighthouse. A few small creeks are present, but a large creek (Dean Creek) is easily accessed. Upland is composed of small hammocks and some constructed causeways, with sand dune complexes east of Dean Creek and extending to the beach. Upper end of the watershed is affected by a culvert at Beach Road and heavy student use of marsh immediately adjacent to culvert. A hydrographic sonde is deployed in Doboy Sound near Commodore Island approximately 1.5km from this site. GCE6 is also the focus of Sapelo Island Microbial Observatory research on microbial diversity and genomics (http://simo.marsci.uga.edu) -81.299522 -81.264378 31.394072 31.371003 Carrs Island - Freshwater marsh site along the northern bank of Hammersmith Creek at the south end of Carrs Island. Upland area is heavily forested. Northern 3/4 of the island was diked for rice agriculture, but the southern 1/4 is undisturbed. A hydrographic sonde is deployed in the Altamaha River near Hammersmith Creek, adjacent to this site. -81.493498 -81.475900 31.348774 31.334364 Alligator Creek - Mid-estuary/salt marsh site on the west side of Friday Cap Creek along the Altamaha River. This is a brackish marsh with salinities around 14 PSU during drought, less than 5 PSU normally. A hydrographic sonde is deployed adjacent to this site in the Altamaha River near Alligator Creek, attached to the US Coast Guard Daymarker 2 pilings. -81.426272 -81.410634 31.317808 31.304063 Rockdedundy Island - Lower estuary tidal creek and marsh site at Rockdedundy Island west of Wolf Island. A hydrographic sonde is deployed approximately 2km from this site in the Altamaha River near Rockdedundy Island, attached to the US Coast Guard Daymarker 201 pilings. -81.346730 -81.326495 31.358142 31.339173 Guo, H., Pennings, S.C. and Wieski, K. 2008. Poster: Physical stress, plant productivity, competition, and diversity in Georgia tidal marshes. Coastal Habitats. 93rd Annual Meeting of the Ecological Society of America, August 3-8, 2008, Milwaukee, Wisconsin. Aboveground biomass and salinity zone https://gce-lter.marsci.uga.edu/public/resources/projects/biomass1PenningsQ5.png see above https://gce-lter.marsci.uga.edu/public/resources/projects/biomass2PenningsQ5.png