The Effects of Beach Nourishment on Surfzone Fisheses and Macroinvertebrates of Bald Head Island, NC (USA)
Recently beach nourishment has become the favored method of maintaining recreational beaches along the Southeastern and Gulf Coasts of the United States. Beach nourishment is often viewed as more environmentally friendly’ when compared to hard stabilization. A growing body of literature, however, demonstrates that beach nourishment has dramatic impacts on the surfzone and nearshore environments. This study examined the effects of one beach nourishment cycle on fishes and macroinvertebrates living in the surfzone of Bald Head Island, NC (USA). Fishes were collected with a 9m X 1.5m seine net (three replicates) in the surfzone at two locations (one nourished site and one non-nourished site) along the south beach of Bald Head Island. Invertebrate abundance was recorded in one-liter sediment samples (three replicates). Water quality parameters were also measured at each site. Sampling took place at least once per month from June 20, 2012 to October 13, 2013. Generally, there were more fishes at the non-nourished site, although not statistically significant. Invertebrate counts were significantly higher at the non-nourished site. When seasonal patterns, water quality parameters and nourishment cycle data were overlain, effects of beach nourishment on the local invertebrate community (and to some extent fish community) were evident. Although beach nourishment may be less impactful than other stabilization methods, it does appear to have an effect on the surfzone community of Bald Head Island.
1 Bald Head Island Conservancy; 2 Methodist University; 3 Ft. Fisher State Recreation Area
191 • Matthew J. Heard1, Katherine F. Smith2, Kelsey J. Ripp2, Melanie Berger2, Jane Chen2, Justin Dittmeier2, Maggie Goter2, Stephen T. McGarvey3, Elizabeth Ryan2
Threats From Disease Increase as Species Move Closer to Extinction
Infectious diseases can pose a significant threat for wildlife species across the world. For those species at risk of extinction from disease, important questions remain unanswered including when on the path towards extinction does disease become a threat and does it co-occur predictably with other threats. Using data from the International Union for Conservation of Nature (IUCN) Red List, we examined the relative role and co-occurrence of threats associated with amphibians, birds, and mammals at six levels of extinction risk (i.e. Red List status categories: least concern, near threatened, vulnerable, endangered, critically endangered, and extinct in the wild/extinct). We tested the null hypothesis that the proportion of species threatened by disease is the same in all six Red List categories. We determined that the proportion of species threatened by disease varied significantly between Red List categories and increased for amphibians, birds, and all species combined as they move from least concern to critically endangered. We also found that disease was infrequently the sole threat impacting species. However, we determined that when species were negatively affected by other threats (e.g. land use or invasive species) they were more likely to be simultaneously threatened by disease. Some potential drivers of these trends include ecological factors, discovery bias among species at greater risk of extinction, clustering of phylogenetically related species in status categories, and data availability. Ultimately, these findings echo calls for baseline data on the presence of disease in species prior to being threatened with extinction.
1 Dept of Biology, Winthrop University, Rock Hill, SC; 2 Dept of Ecology & Evolutionary Biology, Brown University, Providence, RI; 3 Dept of Epidemiology, Brown University, Rock Hill, SC
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192 • Justin D. Latoni, Erin L. Quinlan
Estimating Urban Amphibian Diversity Using Modified Funnel-Traps
Amphibians are declining worldwide due to contaminants, habitat loss, and introduced species. For these reasons, urban or heavily developed areas can be particularly challenging for amphibian populations. The objective of this study was to document the presence of amphibian populations within an urban college campus in Lawrenceville, GA in 2013-2014. Sampling techniques included; dip nets, call tracking, pitfall traps, and funnel traps. It was hypothesized that more amphibians would be observed in or near traps that contained a light source as opposed to those that did not. This was tested with the use of funnel traps in two local aquatic environments; a pond and a stream on the Georgia Gwinnett College campus. Large populations of anurans, specifically Lithobates catesbeianus and L. clamitans, were observed in the pond habitat, while lungless salamander populations, primarily Eurycea spp. and Desmognathus spp., were observed in the stream. The results of the funnel-trap experiment, with and without light sources, yielded varying degrees of success in the pond habitat. Collections within the stream habitat are ongoing and will be completed within the spring season.
School of Science and Technology, Georgia Gwinnett College, Lawrenceville, GA
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193 • Elliott P. Gibbs, Adrian K. O. Hayes, Melissa A. Pilgrim
Development of an Automated Computer Recognizer That Isolates Hyla cinerea Breeding Calls From Sound Files
Two common techniques for monitoring anurans that take advantage of male breeding vocalizations are call surveys and Automated Recording Systems (ARSs). With mass digital storage becoming more affordable, the appeal of digital ARSs has greatly increased. Unfortunately, the volume of recordings produced from ARSs can present logistical difficulties for researchers who must listen to the files. In an effort to reduce the time necessary to manually listen to ARS recordings for calling Green Treefrogs (Hyla cinerea), we used Song Scope to develop an automated computer recognizer for the species. We collected individual treefrog recordings in the field using solid state-recorders with a 460mm shotgun microphone at a distance of ~0.3m from calling frogs. We annotated (i.e., manually identified target portions of the sound file spectrograms that corresponded to quantitative call characteristics) 800 Green Treefrog calls and used the annotations to parameterize our recognizer. We tested the recognizer using 100 ARS breeding chorus recordings (50 contained H. cinerea vocalizations, while the remaining 50 did not). The true positive rate (recognizer correctly identified sound files that contained H. cinerea vocalizations) associated with our recognizer was 85.7%, while its false negative rate (recognizer missed sound files containing H. cinerea vocalizations) was 24.1%. Thus, the accuracy of our recognizer was 80% and its precision was 85.7%. Our work refining automated computer recognizers stands to benefit other researchers interested in using the technology to inventory and monitor anuran populations, and improve standards for use of computer recognizers as tools in ecological research.
Biology, University of South Carolina Upstate, Spartanburg, SC
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194 • Carlos D. Camp1, Jessica A. Wooten2, Zachary I. Felix3
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