2014), has not been widely applied to lotic systems. Habitat augmentation through the use of artificial cover, although a common practice in terrestrial, lentic, and marine environments (Tugend et al.
Although much of the habitat loss is attributed to land use practices within the broader watershed, instream restoration practices have been implemented with varying levels of success (Bond and Lake 2003, Pan et al. Additionally, our results highlight the need to consider site characteristics such as hellbender density and availability of natural cover before deploying artificial hellbender shelters.įreshwater ecosystems are the most imperiled on earth, largely due to habitat loss stemming from declines in water quality, sedimentation, and altered flow regimes (Elkins et al. Our findings suggest modified hydrodynamic shelters are slightly more resilient to the stream environment relative to modified boot designs, presumably due to their heavier weight and larger inner chamber. Hellbenders rarely (range = 0 to 11% of occasions per site) used artificial shelters which precluded our ability to evaluate hellbender preference among shelter designs. Blockage of shelters by sediment was responsible for the majority (96%) of occasions when shelters were deemed unavailable. Shelter availability averaged 71% across all sampled occasions (67% modified boot closed, 69% modified boot open, 77% modified hydrodynamic). We deployed 180 shelters of the three designs ( n = 60 each) across six stream reaches in western North Carolina, measured habitat variables at installation points, and monitored shelters for sediment blockage, dislodgement, and hellbender occupancy. We compared three shelter designs (modified boot design with an open bottom, modified boot design with a closed bottom, and a modified hydrodynamic design) to estimate their probability of availability (remaining in place and not obstructed by sediment) to hellbenders during variable stream conditions.
Although several artificial shelter designs are currently in use throughout the hellbender range, no previous study has compared different designs in the field. Hellbender declines are likely due to a loss of cover and breeding habitat, therefore artificial shelters have been designed for hellbenders to supplement breeding habitat and monitor reproductive success. The hellbender ( Cryptobranchus alleganiensis) is a fully aquatic giant salamander experiencing population declines throughout the eastern United States.
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