How does predator species evenness affect a trophic cascade?
How does predator species evenness affect a trophic cascade?
Dr.
John
Griffin
University of Swansea
Department of Biosciences
University of Swansea
Swansea
SA2 8PP
Wales, United Kingdom
J.N.Griffin@swansea.ac.uk
http://www.sillimanlab.com/people-griffin.php
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.
John
Griffin
University of Swansea
Department of Biosciences
University of Swansea
Swansea
SA2 8PP
Wales, United Kingdom
J.N.Griffin@swansea.ac.uk
http://www.sillimanlab.com/people-griffin.php
Principal investigator
Dr.
Brian
R.
Silliman
Duke University
135 Duke Marine Lab Rd.
Duke University Marine Lab
Beaufort
North Carolina
28516-9721
USA
brian.silliman@duke.edu
https://nicholas.duke.edu/people/faculty/silliman
https://orcid.org/0000-0001-6360-650X
Co-investigator
2026
Project Goals
The goal is the understand how the evenness (in abundances) of the 2 species of predatory mud crab that are present in the marshes around Sapelo influences the strength of top-down control on marsh periwinkles and in turn whether (and how) this cascades to influence cordgrass productivity. We hypothesize that niche differences between the 2 crabs (which we have previously documented) will result in reduced interspecific relative to intraspecific competition, causing an increase in the overall strength of predation on marsh periwinkles and a strengthening of the trophic cascade. We will establish a gradient of predator (mud crab) species evenness in 1 x 2 m field enclosures (with 10 crabs in total - a natural, high, density) and maintain treatments over 4 months. Data will be analysed by fitting (and comparing) a range of linear and non-linear models. Update (1/2012): project extended for a second year.
Associated GCE LTER research questions
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)
marsh
biomass
population density
LTER
NSF
GCE
Eurytium
Panopeus
Spartina
Uca
invertebrate ecology
Overall geographic extent of the research project
-81.307978
-81.176185
31.536369
31.380150
2011-06-01
2012-10-01
estuary marsh complex
Sapelo Island - Sapelo Island on the Southeast Georgia Coast
-81.307978
-81.176185
31.536369
31.380150
GIS file (ArcGIS shapefile)
https://gce-lter.marsci.uga.edu/private/registration/files/gis/GCE-10-2011_GIS_GCE-10-2011-GCE10_GIS_GriffenSilliman.zip
GPS data file (Trimble, Excel)
https://gce-lter.marsci.uga.edu/private/registration/files/gps_data/GCE-10-2011_GPS_GCE10_GriffinSilliman.zip
Map (Google Earth KML/KMZ or map image)
https://gce-lter.marsci.uga.edu/private/registration/files/maps/GCE-10-2011_Maps_Griffin_trophic_study_2011.kmz
Project Location
In the center of Airport marsh (31.25.20.88N 81.17.28.46W)
Equipment
36 1 x 2m cages
Plant and Animal Collection
Yes. 10 crabs will be added to each cage (except for n = 3 controls), so we will add 330 crabs in total (165 Panopues obesus and 165 Eurytium limosum). These will be collected at the study site. John Griffin has a collection permit.