Sapelo Research Application Form
Research Application ID: GCE-110-2021 (submitted: 03/11/2021, status: approved)
Provide a brief title for web display
Effect of megafaunal grazing on marsh insect communities
Investigator Information
On Island Sponsor: GCE SINERR UGAMI GADNR
| Principal Investigator: | Steven C. Pennings | ||
| Home Institution: | University of Houston | ||
| Award Information: | No funding | ||
| 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: | Kori Lugar (University of Houston) | ||
Briefly describe the project goals and methodology
Megafauna (deer, horses, cows) graze in some salt marshes dominated by Spartina alterniflora. They may affect marsh insect communities through several mechanisms: trampling plants, compacting soils, depositing urine and feces, and consuming plants. This experiment will focus on the last mechanism--consuming plants. We will experimentally clip plots to simulate grazing by megafauna, and sample insects to determine how grazing affects insects.
We will mark 16 plots, each 5 x 5 m, using 1/2 inch pvc poles pressed into the ground. We are using a fairly large plot size because insects are mobile, so results from smaller plots would be strongly affected by movement of insects in and out of plots from surrounding areas. Also, we wish to compare our results with a previously-established horse exclusion experiment on Cumberland Island that used 5 x 5 m plots.
We will simulate grazing by clipping half the plots with a weed whacker at the beginning of the study. We will sample insects using a suction sampler and by visual counts of grasshoppers. We will measure plant chemistry (nitrogen content) by clipping two leaves from each plot and having them analyzed for total N content.
Where will the project be located?
South end of Sapelo Island. See attached file for two potential locations, we will pick one in May when we set up the plots.
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: 05/01/2021 End Date: 08/30/2021
How many people will access the site and at what frequency?
Three people for two days in May to demarcate the plots and clip them; two people for two days in June and two days in July to sample insects; two people for one day in August to remove pvc poles marking the plots.
Keywords that describe your project
What equipment will be deployed in the field?
Plots (n=16, each 5 x 5 m) will be marked with pvc poles. The pvc poles will be removed when the study is completed. "Grazed" plots (n=8) will be cut with a weed-whacker four inches above the soil surface once in May to simulate grazing.
Will plants or animals be collected as part of this study?
We will collect insect samples (10 second suction samples from each plot) to measure the effect of the treatment on insects, and plant leaves (two from each plot) to measure plant chemistry.
What are the likely impacts of the project on the site?
None. Based on previous experiments, plants in clipped plots should regrow and be similar to control plots by October.
Will the project design include boardwalks? If not, explain why not.
No, because plots will be visited only a few times.
How long will impacts persist after the research is concluded?
Based on previous experiments, plants in clipped plots should regrow and be similar to control plots by October.
Research Permits:
Georgia DNR Coastal Resources Division: GCE-110-2021_Permit_Pennings_Effects_of_Megafaunal_Grazing_2021_signed (05/01/2021-indefinite)
Study Area Map:
Site Photographs:
Files attached to this application
GCE-110-2021_Maps_Clipped_plots_layout.jpg (Jpeg image, 44.18 kb, submitted 03/11/2021)
GCE-110-2021_Maps_Grazing_experiment_locations.pdf (PDF file, 11311.2 kb, submitted 03/11/2021)
GCE-110-2021_Maps_Grazing_experiment_locations.kmz (Compressed KML file, 0.67 kb, submitted 03/11/2021)
