Do hydrological conditions at creek heads stimulate Sesarma reticulatum recruitment? 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 Huy Vu University of Houston

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

hdvu4@central.uh.edu Co-investigator 2026

The goal of this proposal is to develop an understanding of creek development under the conditions of RSLR that integrates both physical and biological processes. We will test the hypothesis that the hydrological conditions at creek heads stimulate crab recruitment (explaining the high densities of crabs at the creek heads). We will experimentally create artificial creek heads by running 3” PVC pipe perpendicularly from creeks to the marsh platform to test the hypothesis that high densities of Sesarma are driven by high water flow. Pipes will be buried at a depth of 20-40 cm and will end in perforated, vertical standpipes. These “drains” will create localized areas of high water flow on the marsh platform. Water flow through the pipes on ebb tides will be high enough to prevent clogging. The experiment will contain 3 treatments (artificial creek, disturbance control, unmanipulated control), each replicated three times. We will monitor soil redox potential, the oxygen content of water in burrows, marsh surface elevation, crab burrow density, crab species composition, and stem density (n=3 plots per replicate per treatment). Topographic surveys will be made of these areas using standard surveying equipment in order to monitor changes in elevation and to compare them to changes occurring at natural creek heads

Area 3: Responses to Salinity and Inundation (more information)

creek marsh biomass oxygen population density population diversity sedimentology turbidity water flow LTER NSF GCE crustaceans Eurytium Panopeus plants Spartina Uca geology hydrography invertebrate ecology movement of inorganic matter population ecology population studies pore-water chemistry Overall geographic extent of the research project -81.301987 -81.263124 31.486493 31.410854 2012-03-15 2015-08-15

$105,854

estuary marsh complex Duplin River - Duplin River transect used for GCE quarterly hydrographic monitoring surveys. Nominal profiling stations are defined at various locations along the Duplin River west of Sapelo Island, Georgia. -81.301987 -81.263124 31.486493 31.410854

The southeastern corner of Little Sapelo Island.

3" PVC pipes (~10-20m, pipes will be buried, 3.5yrs), boardwalk legs (3.5yrs), 3/4" PVC to mark the experimental plots. All experimental infrastructures will be removed at the end of the experiment.

Common marsh crab species will be collected (Uca, Panopeus, Eurytium, and Sesarma).Crabs will be measured, sexed, and released back to the marsh. Collection of specimens will occur at the end of the experiment. We will be using the general UGAMI collection permits

Wieski, K. and Pennings, S.C. 2014. Latitudinal variation in resistance and tolerance to herbivory of a salt marsh shrub. Ecography. 37:763-769. (DOI: 10.1111/ecog.00498) http://onlinelibrary.wiley.com/doi/10.1111/ecog.00498/abstract