Influence of Sex and Migration Behavior on Reproductive Cost of Spotted Salamanders (Ambystoma maculatum)
Small, isolated wetlands encourage biodiversity by connecting diverse populations of wetland species and providing a habitat for region-specific species. In particular, many semi-aquatic species use ephemeral wetlands for breeding and juvenile development. Understanding the factors that influence amphibian reproduction is critical to informing conservation efforts and wetland regulations. To address this issue, we examined body mass changes of spotted salamanders (Ambystoma maculatum) during their seasonal breeding migrations. We sampled salamanders 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 completely encircling the wetland with 38 pitfall traps at 10 m intervals. Traps were checked daily during two annual breeding migrations January - February 2013 and 2014 and salamanders marked and measured (i.e., sex, mass, snout-vent length, and total length). The relationship between body mass changes and explanatory factors including sex, duration of stay at wetland, aquatic movement frequencies, and minimum movement distance were examined using a set of candidate linear mixed models selected a priori and compared using Akaike’s Information Criterion (AICc). Our results revealed the relationship between body mass changes, sex, and migration behavior in A. maculatum, demonstrating the relative importance of these factors in determining reproduction costs. Our findings will help inform aquatic and upland habitat management and policy impact on the reproductive health of semi-aquatic amphibians.
P120 • Codie Picariello, Elizabeth Tuttle, Matthew N. Waters, Gretchen K. Bielmyer
Epiphytic Algal Community Structure in Response to Watershed Land Use and Environmental Stressors in Four South Georgia Streams
Epiphytic algae, or biofilms, are important components of stream ecosystems, providing a source of organic carbon, oxygen, and other services. These services can be impacted by various environmental and anthropogenic factors such as flow rate, light, and watershed land use. Here, we analyzed epiphytic algal community composition from four streams in South Georgia of different orders and land uses, in order to understand the impacts of these stressors on stream primary producers . The streams sampled were One Mile Branch (1st order, urban land use), Sugar Creek (2nd order, urban and forest land use), Little River (3rd order, forest and agricultural land use), and Withlacoochee River(4th order, forest, agricultural, and urban land use). Epiphytic algae developed on tile traps that were placed into the streams and sampled on a monthly basis. Algal community composition was determined by measuring chlorophylls and carotenoids through high performance liquid chromatography (HPLC). Community structure for all four streams was predominantly diatoms, but green algae were also a significant component. Detrital material increased with gauge height for lower order streams (first-third), but decreased with the highest order stream sampled (Withlacoochee, fourth order). For the majority of pigments measured, total pigment amounts decreased in correlation to gauge height with the exception of the lowest order stream. Our results show that epiphytic community structure responded greater to environmental factors such as precipitation and DOC rather than watershed land use.
Dept of Biology, Valdosta State University, Valdosta, GA
P121 • Elizabeth G. Dobbins, Kristin A. Bakkegard
Efficacy of Rock Vanes at Reducing Local Erosion in an Urban Stream in Jefferson County, AL
One of the challenges of urbanization is the increase in stormwater runoff due to a greater area of impervious surface. In response to increased water volume, streams enlarge by eroding the banks and scouring the streambed. The net result is a greater sediment load in the water column. Rock vanes are used to mitigate these effects by channeling water energy midstream. Little is known about the long-term efficacy of rock vanes in reducing in-stream sediment. We implemented two new methods of investigating sediment deposition: ceramic tiles and sediment scoops. Both methods were used over four years in four regions of Shades Creek, a third order urban stream: 100m upstream of 10 rock vanes (control), the upstream rock vanes, the downstream rock vanes, and 50m downstream of the rock vanes (control). Before installation of the vanes, the highest sediment deposition was in the area of highest local erosion, the reason the rock vanes were needed. After installation, there was significantly less sediment below this site; however, during times of low rainfall (<2), we detected an increase in local sediment deposition caused by an upstream commercial construction project. The downstream vanes and downstream control had a significant increase in the smallest, most damaging to the biota, sediments (< 250 microns). During high rainfall (>4), local erosion persisted and the downstream vanes had the highest sediment deposition. Although rock vanes may mitigate sediment deposition, they are not a panacea for urban stream syndrome.
Dept of Biological and Environmental Sciences, Samford University, Birmingham, AL.
P122 • Cliff H. Crummey, James T. Ragan, Matthew N. Waters, Gretchen K. Bielmyer
The Impacts of Watershed Land Use and Environmental Factors on Sediment Transport and Light Attenuation in Four Streams in South Georgia
Sediment and organic matter inputs are primary geomorphic processes in streams and can greatly impact ecological functions. While precipitation can influence sediment inputs, land use and seasonality can alter the type of organic matter entering the streams. The focus of this research was to determine how land use and other environmental factors relate to material transport, substrate deposition, and light attenuation in streams. Two of the four streams in our study were surrounded predominately by forest and agriculture land use: the Withlacoochee (4th order) and the Little River (3rd order). The remaining two: One Mile Branch (1st order) and Sugar Creek (2nd order) were largely impacted by urban areas. Sampling was conducted on two week intervals to monitor total suspended solids (TSS), bed substrate, and dissolved organic matter. TSS was sampled through filtration, and bed substrate was identified by sieving. Filtered water samples were analyzed for light blocking properties using a spectrophotometer to determine chromophoric dissolved organic matter. Results indicate that stream substrates were dominated by sand and boulders (>98%) with organic matter accounting for around 0.02% of total bedload. Total suspended solids for lower order streams increased rapidly following a precipitation event, while larger order streams indicated a delayed influx from tributaries. Chromophoric dissolved organic matter was higher in larger streams and a rise in gauge height showed a decrease in CDOM in all four streams. Results show that general patterns of sediment transport and light attenuation relate to both precipitation and land use in South Georgia streams.
Biology Dept, Valdosta State University, Valdosta, GA
P123 • Christian R. Barrett, Timothy Burns, Vladislav Gulis
