Inter-Research > ESR > v41 > p167-181  
ESR
Endangered Species Research

via Mailchimp

ESR 41:167-181 (2020)  -  DOI: https://doi.org/10.3354/esr01014

Evaluating artificial shelter arrays as a minimally invasive monitoring tool for the hellbender Cryptobranchus alleganiensis

Catherine M. Bodinof Jachowski1,3,*, Beth E. Ross2, William A. Hopkins1

1Department of Fish and Wildlife Conservation, 106 Cheatham Hall, Virginia Tech, Blacksburg, VA 24060, USA
2US Geological Survey, South Carolina Cooperative Fish and Wildlife Research Unit, Department of Forestry and Environmental Conservation, 261 Lehotsky Hall, Clemson University, Clemson, SC 29634, USA
3Present address: Department of Forestry and Environmental Conservation, 261 Lehotsky Hall, Clemson University, Clemson, SC 29634, USA
*Corresponding author:

ABSTRACT: Hellbenders Cryptobranchus alleganiensis are critically imperiled amphibians throughout the eastern USA. Rock-lifting is widely used to monitor hellbenders but can severely disturb habitat. We asked whether artificial shelter occupancy (the proportion of occupied shelters in an array) would function as a proxy for hellbender abundance and thereby serve as a viable alternative to rock-lifting. We hypothesized that shelter occupancy would vary spatially in response to hellbender density, natural shelter density, or both, and would vary temporally with hellbender seasonal activity patterns and time since shelter deployment. We established shelter arrays (n = 30 shelters each) in 6 stream reaches and monitored them monthly for up to 2 yr. We used Bayesian mixed logistic regression and model ranking criteria to assess support for hypotheses concerning drivers of shelter occupancy. In all reaches, shelter occupancy was highest from June-August each year and was higher in Year 2 relative to Year 1. Our best-supported model indicated that the extent of boulder and bedrock (hereafter, natural shelter) in a reach mediated the relationship between hellbender abundance and shelter occupancy. More explicitly, shelter occupancy was positively correlated with abundance when natural shelter covered <20% of a reach, but uncorrelated with abundance when natural shelter was more abundant. While shelter occupancy should not be used to infer variation in hellbender relative abundance when substrate composition varies among reaches, we showed that artificial shelters can function as valuable monitoring tools when reaches meet certain criteria, though regular shelter maintenance is critical.


KEY WORDS: Population monitoring · Nest box · Substrate · Bayesian mixed models · Occupancy · Artificial cover


Full text in pdf format
Supplementary material 
Cite this article as: Bodinof Jachowski CM, Ross BE, Hopkins WA (2020) Evaluating artificial shelter arrays as a minimally invasive monitoring tool for the hellbender Cryptobranchus alleganiensis. Endang Species Res 41:167-181. https://doi.org/10.3354/esr01014

Export citation
Mail this link - Contents Mailing Lists - RSS
Facebook - - linkedIn