Theory and practice of the hydrodynamic redesign of artifical hellbender habitat
The success of nest boxes in Missouri led researchers to test whether similar management tools could increase C. a. alleganiensis populations in the streams of western North Carolina, where these salamanders are listed as a Species of Special Concern (Messerman 2014). Fifty-four nest boxes were constructed following the boot-shaped design of Briggler and Ackerson (2012) in May 2013, and were installed across five known C. alleganiensis stream sites between late June and early August 2013. Messerman (2014) then monitored each nest box every three to four weeks through November 2013, and the boxes were revisited in August 2014 and July 2015 to observe structural condition and occupancy (Messerman, pers. obs.). Of the 54 nest boxes, only two structures at a single site were confirmed as inhabited in 2014 and 2015, and no breeding events were detected (Messerman, pers. obs.). Moreover, many of these ~50 lb concrete boxes moved in flood events or accumulated sediment at the downstream tunnel entrance (Messerman 2014). The low success of the boot-shaped nest box design in North Carolina may be attributed to the sites generally being narrower and shallower than those in Missouri, with much of the substrate consisting of bedrock slabs covered by relatively thin layers of rock, gravel and silt. Here we address the observed shortcomings of the original North Carolina design through the lens of engineering, and present a new and easily implemented nest box model for use in streams like those found in western North Carolina.
Publication Date: 2016
DOWNLOAD FILE — PDF document, 966 kB (990,183 bytes)
