Sapelo Research Application Form
Research Application ID: GCE-118-2021 (submitted: 11/29/2021, status: approved)
Provide a brief title for web display
Disturbance across elevation
Investigator Information
On Island Sponsor: GCE SINERR UGAMI GADNR
| Principal Investigator: | Steven C. Pennings | ||
| Home Institution: | University of Houston | ||
| Award Information: | GCE-LTER main award | ||
| Mailing Address: | Department of Biology and Biochemistry | Phone Number: | (713) 743-2989 |
| University of Houston | E-mail Address: | scpennin@central.uh.edu | |
| Houston, Texas 77204-5513 | |||
| Co-investigators: | |||
Briefly describe the project goals and methodology
Our goal is to understand how intertidal marshes recover from disturbance, with a focus on whether the recovery rate varies as a function of intertidal elevation. We hypothesize that plants at very low and very high elevations are stressed, and will recover more slowly than plants at intermediate elevations. To ensure that our results are general, we will work at three sites: one dominated by Spartina alterniflora (salt marsh), one dominated by Spartina cynosuroides (brackish marsh) and one dominated by Zizaniopsis miliacea (fresh marsh). These sites are chosen 1) to represent a salinity gradient, and 2) because each species covers pretty much the entire intertidal gradient so that we won't confound elevation with species (as we might if we worked at a site with Juncus in t he mid-marsh and Spartina in the low marsh).
At each site, we will set up 15-20 pairs of plots, spanning the entire elevational range of the plant being studied. Pairs of plots will be closely spaced where elevation changes quickly (like near the creek) and spread out more where the marsh is relatively flat (the marsh platform). The location and elevation of each plot will be measured with RTK GPS. Total number of plots is 120 (3 sites x 20 locations x 2 treatments).
Plots will be 2 x 2 m. We will trample the vegetation and cover one plot in each pair with a tarp from March to May 2022 (10 weeks) to kill underlying vegetation (this simulates wrack disturbance). We will trench around the disturbed plots with a shovel to sever rhizome connections that might be supporting shoots inside the plots.
We will uncover the disturbed plots in May 2022 (if vegetation is not 100 percent dead, we'll leave the tarps on a few weeks longer) and will monitor them regularly, perhaps in June, July, August, and October of 2022, and March, May, June, July, August of 2023. The monitoring frequency will be adjusted based on plant regrowth rates; however, we expect vegetation to recover within 2-4 years in most plots. Probably the entire experiment can be terminated after 4 growing seasons.
Where will the project be located?
See attached maps for approximate site locations. The salt marsh site will be at the south end of Sapelo Island, the brackish site on the Altamaha River estuary, south of highway 17, and the fresh site on the Altamaha River estuary, north of I-95.
How will you provide GPS coordinates for study sites?
I will provide a provisional map and arrange with my sponsor to collect and register GPS coordinates
What are the expected start and end dates of the project?
Start Date: 11/01/2021 End Date: 10/01/2026
How many people will access the site and at what frequency?
Three people will access each site four or five times in year 1, two or three times in year 2, and annually in following years.
Keywords that describe your project
What equipment will be deployed in the field?
Each plot will be marked with 3/4 inch pvc stakes. During the initial disturbance treatement, plots will be covered with tarps for 2-3 months to create the disturbance. These will then be removed and we will watch the plots recover.
Will plants or animals be collected as part of this study?
We will clip a small number of shoots to generate allometric height-mass relationships for plants at each site. Otherwise, plants will be measured non-destructively. Invertebrates will not be collected.
What are the likely impacts of the project on the site?
The experiment simulates wrack disturbance, which is a common disturbance in GA marshes. We expect that vegetation will recover to control conditions in 2-4 years, depending on site and plot.
Will the project design include boardwalks? If not, explain why not.
No. Visits will be infrequent enough that boardwalks would be more destructive than the visits.
How long will impacts persist after the research is concluded?
We will monitor the plots until the effects of disturbance are no longer apparent, likely 2-4 years after the experiment starts.
Research Permits:
Georgia DNR Coastal Resources Division: GCE-118-2021_Permit_RLS20220003_Pennings_MarshRecovery_signed (03/16/2022-indefinite)
Files attached to this application
GCE-118-2021_Maps_Disturbance_elevation_brackish_marsh_site.pdf (PDF file, 11849.6 kb, submitted 11/29/2021)
GCE-118-2021_Maps_Disturbance_elevation_fresh_marsh_site.pdf (PDF file, 10693 kb, submitted 11/29/2021)
GCE-118-2021_Maps_Disturbance_elevation_plot_layout.pptx (MS PowerPoint, 972.96 kb, submitted 11/29/2021)
GCE-118-2021_Maps_Disturbance_elevation_salt_marsh_site.pdf (PDF file, 9837.51 kb, submitted 11/29/2021)
GCE-118-2021_Documents_Disturbance_elevation_plot_layout.pdf (PDF file, 1015.28 kb, submitted 11/29/2021)
