Determining the Presence of the Eastern Hellbender (Cryptobranchus alleganiensis alleganiensis) and Differentiators of Occupied vs. Unoccupied Habitats in Bent Creek, Buncombe County, North Carolina

UNCA Author/Contributor (non-UNCA co-authors, if there are any, appear on document)
Alexander Levine, Student (Creator)
University of North Carolina Asheville (UNCA )
Web Site:
David Gillette

Abstract: The Eastern Hellbender (Cryptobranchus alleganiensis alleganiensis) is a large aquatic salamander found in cool, clean, highly oxygenated rivers and streams within the eastern United States. Hellbender populations have been steeply declining over the past century and are a protected species in most states where they are found, including North Carolina where they are listed as a species of special concern. North Carolina contains approximately 3000 waterways that could potentially support hellbender populations. It is vital to survey these waterways to better understand the distribution of the Eastern Hellbender and what environmental factors enable these systems to support threatened hellbender populations. Although smaller tributaries could potentially act as important refugia for both larval and adult hellbenders, most surveys had thus far been focused upon scattered sections of larger waterways, generally using substrate quality and the presence of large cover rocks as primary determinants for site selection. Until this project was completed, no survey in western North Carolina had ever covered an entire stream system. During May, June and July of 2013, the entirety of Bent Creek was surveyed, beginning at the mouth (the French Broad River) and concluding at the Lake Powhatan dam. Four adult Eastern Hellbenders were found, with two captures and two tactile encounters/escapes. In October 2013, three occupied sites and three unoccupied sites were examined, determining the number of cover rocks, the temperature, dissolved oxygen and dominant substrates at each site. While temperature and dissolved oxygen did not vary significantly, occupied stream sections had significantly coarser substrates and a much higher occurrence of cover rocks than unoccupied sections. This data indicated that commonly used surveying techniques relying on cover rocks and substrate composition are likely the most effective means of selecting survey sites in large aquatic systems. Future research might examine whether the Eastern Hellbender population at Bent Creek is or has the potential to become a viable breeding population, if the stream conditions are amenable to larval recruitment, and whether breeding could be encouraged with the use of habitat improvement and artificial nesting rocks.

Additional Information

UNC Asheville - Journal of Undergraduate Research
Language: English
Date: 2013
Eastern Hellbender, salamander, Bent Creek, North Carolina

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