Graduate Exit Seminar

Kaitlin Kinney will present her Masters Exit Seminar at 10:30 a.m. in 245 Kottman Hall on Friday, November 3, 2017. Her presentation is The Role of Biotic Resistance Through Predation on the Invasion Success of the Green Porcelain Crab (Petrolisthes armatus) into Nearshore Oyster Reef Communities.

The northward spread of the non-native, invasive filter feeding crab Petrolisthes armatus into oyster reef communities along the Southeastern US is hypothesized to be limited by cold snaps associated with northern winters. However, several native predators in oyster reefs have been shown to consume this abundant and profitable prey item, suggesting that biotic resistance through predation may be an additional factor limiting its northward spread. My main objectives were to 1) determine if the per capita predation risk exerted by native predators might be a factor that explains the current distribution of P. armatus, and 2) test whether the relative abundance of alternative native prey affects the consumption and preference of P. armatus by a native predatory crab Panopeus herbstii. I predicted that if predation limits the spread of P. armatus, then predation risk should be highest at the northern edge of its range. Additionally, I predicted that if the relative abundance of native prey affects the consumption of P. armatus by a native predator, then consumption of P. armatus should be higher when P. armatus is proportionally more abundant than native prey. To test these hypotheses, I conducted a field study to quantify predation risk across 8 invaded estuary sites along the Southeastern US coast from St. Augustine, FL to North Inlet, SC and conducted a controlled lab experiment to quantify the consumption and preference of P. armatus when in low to high abundance relative to alternative native prey. While predation rates were high (68.2 – 98.2%) across sites, there was no significant relationship between predation and latitude across the 8 invaded estuaries. Furthermore, while P. herbstii increased consumption of P. armatus in response to increased abundance in the tank, P. herbstii always showed a preference for native prey regardless of its relative abundance. Overall, I found no evidence of biotic resistance through predation, suggesting that native predators do not prevent the spread of P. armatus and this species is likely to continue its expansion into northern waters as sea temperatures increase with climate change.

Advisor:  Dr. Lauren Pintor