Urbanization is increasing worldwide and land conversion for human needs is reducing the amount of microhabitats in which many species can persist. One type of organism that relies on the existence of microhabitats is the land snail. Land snails are extremely diverse and tremendously understudied. However, these taxa may be an indicator of the health of a local environment. In this study, we measured how land snail diversity varied across a 25-year successional gradient (in 3 plots aged 15, 20, and 25 years) to examine the impact of land use change in South Carolina. We collected snails in two ways: 1) through a timed visual search for macrosnails and 2) by collecting soil samples for microsnails. We then compared generic diversity and turnover across successional plots using both the Shannon-Weiner Diversity Index and the Jaccard Similarity Index. Using these analyses, we found that diversity was highest in the intermediate aged plot (H=1.189). In addition, we also determined that there was significant turnover of taxa between plots (average generic similarity between plots was 58%). Collectively, our data indicate that the process of succession can impact snail diversity. However, more research is needed to fully understand the impact of land use on terrestrial snails.
Changes in Community Structure of Two Exotic Invasive Bivalves in Lake Erie
The invasive mussels, Zebra (Dreissena polymorpha) and Quagga (Dreissena bugensis), have had devastating economic and ecological impacts. In addition, Quaggas are replacing zebra mussels as the dominant species in western basin of Lake Erie. This experiment tracked population characteristics (density, species proportions, size-frequency). We also measured the effects of predation on mussels’ population by an invasive fish (Round Goby). Gobys eat smaller, newly settled mussels. If predation is changing mussel populations then in subsequent years, the number of young mussel offspring in the ecosystem should decrease. To determine if population characteristics of mussels have changed, benthic samples were collected from rocks (2008 and 2010). To test the effects of predation by the Goby, lines holding settlement plates (3 x 5 cm2) protected by cages were suspended 2 meters above the bottom by a buoy (May-August 2010). Species were separated and shell lengths were measured. Preliminary results show that density has declined and Quaggas were the dominant species in 2008 making up 71% of the benthic population and 62% of the settlers and 81% and 65%, respectively, in 2010. Gobies appear to be limiting mussel recruitment thereby reducing the impact these mussels have on the ecosystem.
Dept of Biology, Francis Marion University, Florence, SC
P7 • Benjamin E. Hardie, F. Whitner Chase, Maximilian M. Kern, Leigh Anne Harden, Shannon E. Pittman, Michael E. Dorcas
Evaluation of Individual Identification Methods for Spotted Salamanders (Ambystoma maculatum)
Capture-mark-recapture studies are valuable to conservation decision-making as they allow for the evaluation of demographic parameters of a population. In capture-mark-recapture studies, spotted salamanders (Ambystoma maculatum) are often marked with visible implant elastomers (VIEs), allowing for individual salamanders to be identified upon recapture. However, this elastomer coding system is expensive, invasive, and offers a finite number of codes, making it unsuitable for a long-term study. Thus, we have developed a new coding system that identifies spotted salamanders based on individuals’ unique spot patterns. In this study, we compared the two coding systems to determine the effects of both identification method and observer on identification accuracy. Over one breeding season we monitored A. maculatum entering and leaving a 0.5 ha ephemeral wetland in the North Carolina Piedmont using 40 aquatic funnel traps and a 400 m drift fence with pitfall traps at 10 m intervals completely encircling the wetland. Several Davidson College Herpetology Laboratory students blindly identified each individual A. maculatum using both spot pattern codes and VIE codes (if previously marked). Photographs were also taken of each individual for verification of spot pattern codes when recaptured. Identification accuracy was compared among observers, between coding systems, and among captures. Our study provides recommendations for use of an identification system using spot pattern allowing it to be implemented in long-term studies of A. maculatum and potentially adapted for use in other species.
P8 • Grayam R. Sailor-Tynes, Maximilan M. Kern, Michal E. Dorcas
Natural History of Eastern Box Turtles (Terrapene carolina carolina) in North Carolina: A Study Based on Citizen Science
An extensive study of eastern box turtles (Terrapene carolina carolina) throughout North Carolina was conducted by the Davidson College Herpetology Laboratory and trained citizen scientists working through the Box Turtle Connection. Turtles were captured opportunistically and were measured and individually marked. Analysis of measurements yielded capture data, body condition indices, instances of injury and recapture as well as seasonal capture rates. A total of 2,424 turtles were captured and 597 instances of recapture were documented. More adults and more males than females were captured overall. Body condition varied across seasons and ecoregions and along with capture frequency suggested substantial variation for turtles in different ecoregions. Instances of injury ranged from 5.7% to 29% throughout the state. Results of this study suggest that citizen science can be extremely useful when studying species such as the box turtle that are difficult to sample consistently, and can provide crucial information for conservation efforts.
Dept of Biology, Davidson College, Davidson, NC
P9 • Beau B. Gregory1, John O. Whitaker, Jr.2, Gregory D. Hartman3
