Sapelo Research Application Form
Research Application ID: GCE-133-2023 (submitted: 07/19/2023, status: approved)
Provide a brief title for web display
Using Stable Isotopes to Determine Aratus pisonii food resource usage in salt marshes and on docks
Investigator Information
On Island Sponsor: GCE SINERR UGAMI GADNR
| Principal Investigator: | Amanda C. Spivak | ||
| Home Institution: | University of Georgia | ||
| Award Information: | GCE-LTER to Spivak | ||
| Mailing Address: | Marine Science Rm. 164 | Phone Number: | (706) 542-5709 |
| Marine Sciences | E-mail Address: | aspivak@uga.edu | |
| Athens, Georgia 30602-3636 | |||
| Co-investigators: | |||
Briefly describe the project goals and methodology
This is an undergraduate thesis project, led by Cailyn Bowser. Her proposal is:
As climate change progresses, more warm adapted species are expanding their habitat ranges poleward into previously harsh environments due to the lack of severe winters which often delay rapid habitat expansion. Climate-induced species range shift can cause changes in species behaviors and patterns in novel ecosystems where they are exposed to new environments and species interactions. The ecology of resident species can be altered as well due to new resource use and space partitioning as they interact with the new species. In some cases where different species are evolutionarily associated with each other, one species can migrate quicker than the other due to differences in how they adapt to a new environment.
Aratus pisonii, known as the mangrove tree crab, is traditionally found in mangrove stands and is considered an important foundational species to their habitat, contributing to leaf litter processing and nutrient cycling. Due to warming temperatures and more mild winters, both mangroves and A. pisonii are migrating up the Atlantic seaboard into salt marshes. Aratus pisonii recently broke off from the paired crab-mangrove migration to inhabit salt marshes and can be found at higher latitudes than the northernmost mangrove. Aratus pisonii can now be found on Sapelo Island, GA, where they must adapt to a completely different habitat structure which generates different species interactions and resources. One adaptation is their use of built infrastructure, such as docks, as habitat substitutes due to their thermal buffering capacity, protection from predators, food sources, and A. pisonii's natural tendency to climb structures which help in facilitating their migration northward.
As A. Pisonii continues migrating northward into salt marshes, it is important to investigate how they are surviving in novel environments to predict how they might alter the ecology of native species. I propose to use stable isotopes to study what A. pisonii are eating in salt marshes to answer my research question "how are A. pisonii adapting their habitat selection and food resource use in novel habitats with natural marsh and human built components?"
To answer my question, I will choose seven paired dock and adjacent marsh sites on Sapelo Island, GA, along waterways such as Post Office Creek and Laboratory Creek. I will collect A. pisonii from every site, measure their dimensions, and use their claw tissue for carbon and nitrogen stable isotope analyses to help determine what food sources go into tissue production. In addition, unique vegetation, algae, and insects from every site will be collected and processed in the lab for carbon and nitrogen isotopes under the assumption they are possible food sources for the crabs to be compared to the crab isotope results. Data from the experiment will be used to create a mixing model to analyze A. pisonii space and food resource use on Sapelo Island as well as predict possible food behaviors in other temperate salt marshes.
My roles in the study include working to formulate the research topic, developing methodology, conducting the field and in lab work, and analyzing the resulting data.
Where will the project be located?
31.435297° -81.280833° 31.435589° -81.281716° 31.434370° -81.281178° 31.432013° -81.282740° 31.437611° -81.280171° 31.397333° -81.281559° 31.396333° -81.280011° 31.395459° -81.278879° 31.396211° -81.280823° 31.394867° -81.279029° 31.393518° -81.284219° 31.393274° -81.285517° 31.399338° -81.281739°
How will you provide GPS coordinates for study sites?
GPS coordinates are listed in the project location field
What are the expected start and end dates of the project?
Start Date: 06/01/2023 End Date: 12/18/2023
How many people will access the site and at what frequency?
1-2 people 4-6 times total over the entire monitoring period.
Keywords that describe your project
What equipment will be deployed in the field?
acrylic settling plates (5" x 5") will be weighted with 6-hole bricks and suspended with nylon rope from dock pilings below the high tide line. Deployments will be < 1 month. HOBO temperature pendants will be deployed on docks with zip ties and in the marsh with PVC poles and zip ties.
Will plants or animals be collected as part of this study?
Above ground leaves will be collected from Spartina alterniflora and Juncus roemerianus. Only a handful of leaves will be collected one time.
Mangrove crabs (Aratus pisonii) will be collected from docks and marshes (if found) and will be preserved for stable isotopes. Up to 50 individuals.
What are the likely impacts of the project on the site?
None.
Will the project design include boardwalks? If not, explain why not.
No because sampling is periodic and visits will be ~30 minutes for surveys.
How long will impacts persist after the research is concluded?
there will be no lasting impacts.
Files attached to this application
GCE-133-2023_Documents_Mangrove_crab_diet_summary_080223.docx (MS Word file, 12.68 kb, submitted 08/02/2023)
