Improving the Utility of Artificial Shelters for Monitoring Eastern Hellbender Salamanders (Cryptobranchus alleganienses alleganiensis)
Artificial shelters show great promise as novel, non-invasive tools for studying
hellbenders, but their use thus far has faced several challenges. During initial trials in multiple
river networks, artificial shelters routinely became blocked by sediment and dislodged during
high stream discharge events, and were rarely used by hellbenders. We sought to determine
whether these complications could be overcome via alternative shelter design, placement, and
maintenance. Between 2013 and 2018, we deployed 438 artificial shelters of two different
designs across ten stream reaches and three rivers in the upper Tennessee River Basin. We
assessed evidence for several hypotheses, postulating broadly that the availability, stability, and
use of artificial shelters by hellbenders would depend on how shelters were constructed,
deployed, and/or maintained. We found that maintaining shelters at least once every 40 days
limited sediment blockage, and building ~ 40 kg shelters with 3-4 cm thick walls and recessed
lids improved their stability during high discharge events. Additionally, we found that
hellbenders most frequently occupied and nested in artificial shelters when they were deployed
in deeper (~50+ cm) portions of reaches with high adult hellbender densities. Our results suggest
that artificial shelters can serve as effective tools for studying hellbenders when designed,
deployed, and maintained with these advancements, but also highlight some limitations of their
use.
Publication Date: 2019
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