Predators and their prey evolve together throughout time, with checks and balances that allow both species to persist. When invasive species invade a new habitat, often these balances are thrown off, as no native predators have the knowledge and thus ability to eat and control these species. This often results in alarmingly high densities of invasive species which can have catastrophic effects on the ecosystem as a whole. I am curious as to whether ecosystems that have invasive species are able to eventually assimilate these species and return to a balanced state. This assimilation of invasive species within an ecosystem would rely on the ability of native predatory species to eat a new prey- the invasive. But how can native predators learn to eat invasive prey? It is predicted that as time progresses and the two species interact, eventually the native predator will consume the invasive prey. However, little is known about how long we can expect it to take for a native predator to eat an invasive prey or what sort of environmental or biological variables could expedite the ability of a predator to eat the invasive prey. My research will answer this gap of knowledge by exploring the ability of a native predatory species, like the Atlantic Mud Crab, Mummichug and Blue Crab, to consume and control an invasive prey crab species, Petrolisthes armatus. Using tethering methods to quantify predation rates, I can begin to understand how native predators could mitigate the devastating impacts of invasive species.
Description of Project:
Petrolisthes armatus, the green porcelain crab, is native to Brazil but was introduced into oyster reef habitats in Florida and has spread as far north as South Carolina. This expansion has created established populations of P. armatus along the coast that vary in their time since invasion. In this case, space can be substituted for time as southern populations (FL) of native predators have a longer evolutionary history than the most northern populations (SC). Using this knowledge, I hypothesize that native predator populations in the southern invaded range will more readily consume P. armatus.
My main goal is to quantify the predation rates of native predators on P. armatus within the invaded range, from St. Augustine, FL to Georgetown, SC. In order to reach this goal I will deploy tethered P. armatus on oyster reefs at 8 different sites along this range. P. armatus will be tethered by attaching fishing line to their carapace on one end and 35mm of line attached to a stake in the oyster reef. I will also take three ¼ m2 plots of oyster reef to enumerate the relative abundance of P. armatus and other reef dwelling prey items, like crabs, mussels and oysters. In order to quantify the abundance of native predators I will use an array of traps (1 crab pot, 1 fish trap and 1 minnow trap) per reef. I have specifically designed this experiment to cut down on the impacts made on the reef. We will be removing oyster shell in order to quantify the animals within but all oysters and associated fauna will be returned to the estuary at site of their capture. All native predators trapped will be sized, sexed and returned to the estuary on site. No animals will be removed or preserved. All invasive P. armatus individuals will not be returned to the estuary. Loose rubble and shell from the surrounding site will be placed over the excavated ¼ m2 plots.
I am unaware of any previous studies looking at P. armatus within the Sapelo Sound. Sapelo Island is within the invaded range of P. armatus and thus would provide an excellent chance to quantify how predators are repsonding to this invasive prey. In addition, my more southern sites will provide a comparison of predators with varying experience with this invasive prey. This data will be essential in understanding how quickly native predators can respond to an invasive prey in order to provide some biological control.
I understand that Sapelo Island is a busy place in the summer and so upon approval I will communicate with the island staff on which dates work best for visiting and I am flexible on when this project can be completed. I will complete the methods above on easily accessible sites and will not require boat acommodations.
University of Georgia Odum School of Ecology 2013-2015
Lab Technician for Dr. James E. Byers at the Skidaway Institute of Oceanography
Manage laboratory needs including ordering supplies, organizing permits, and boat maintenance.
University of Georgia Department of Microbiology
Student Worker for Dr. Zachary Lewis 2011-2013
Manage laboratory needs including stocking solutions, inventorying chemicals and maintaining cleanliness.
Studying the predator prey interactions between a native predatory crab Panopeus herbstii and a novel invasive crab Petrolisthes armatus.
Masters Student for Dr. Lauren Pintor at the Ohio State University 2015-CE Studying the invasive seaweed Gracilaria vermiculophylla and its effects on southeastern US estuaries.
Lab technician working for graduate student Linsey Haram through the Odum School of Ecology 2013- 2015
Assist in studies of seasonal survey abundances of G. vermiculophylla in fixed sites along the southeastern US coast, changes in detrital pathways through stable isotope analysis
and chlorophyll-A analysis, G. vermiculophylla’s effect on infaunal communities through the use of manipulative field experiments, fish and invertebrate feeding trials of G. vermiculophylla, and the cascading effect of G. vermiculophylla on predation of native invertebrate communities by migratory bird species in Wassaw Sound, Savannah GA.
Studying the effects of temperature and predation on the prevalence of the protist Perkinsus marinus in the native eastern oyster Crassostrea virginica.
Volunteer for graduate student Jennifer Malek through the Odum School of Ecology Summer 2011
Assist in site scouting, constructing field cages, collecting oysters and predatory crabs,
deploying manipulative field experiment, and oyster tissue collection for DNA isolations.