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3 September 2021 Leaf litter and rock bag surveys allow for detection and DNA barcoding characterization of diet composition of dusky salamanders
Natalie Paige Hart, Reuben Daniel Carpenter, Shem David Unger
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Salamanders are vital components of many aquatic ecosystems food webs and are often found in diverse habitats, including both urban and semi-rural environments. The northern dusky salamander, Desmognathus fuscus is a common salamander found throughout the southeastern United States and is an important predator of aquatic macroinvertebrates. However, very little is known about either diet or suitable survey techniques for this species in human altered habitats, which may vary based on level of urbanization (e.g., are either spring-fed, derived from ponds, modified ditches, etc.). Therefore, we used multiple survey methods (leaf litter bags, novel rock bags, and quadrat sampling) to quantify relative abundance of D. fuscus on Wingate University's campus, in Wingate, North Carolina. We also collected and identified aquatic invertebrates from bag sampling and diet items obtained from gastric lavage of adult salamanders from quadrat sampling. Leaf litter bags contained the highest relative abundance of salamanders (47) compared to rock bags (14), with quadrat sampling yielding primarily adult salamanders. We noted a significant difference among our two sites sampled in salamander relative abundance (Man-Whitney U test = 67.5, p < 0.001), possibly due to reduced water quality, canopy cover, or less available habitat. Aquatic worms represented the most frequent potential food item sampled from both bag types (61.9%), followed by Diptera nymphs (13.7%). Potential food items from leaf and rock bags as well as gastric lavage samples collected from Desmognathus were further identified using DNA barcoding. These food items included a variety of both aquatic and terrestrial invertebrates (annelid worms, springtails, chironomids, carpenter ants, shore flies, wasps, and wood lice). These results indicate urban salamanders may forage both in the stream and in the riparian zone or advantageously consume insects which fall into the stream. This study adds to our body of knowledge on the ecology of salamanders in urban stream environments.

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Natalie Paige Hart, Reuben Daniel Carpenter, and Shem David Unger "Leaf litter and rock bag surveys allow for detection and DNA barcoding characterization of diet composition of dusky salamanders," BIOS 92(2), 21-30, (3 September 2021).
Received: 13 November 2019; Accepted: 5 June 2020; Published: 3 September 2021

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