The Eastern Hellbender. Photo: Pete Oxford

HellbenderHellbenders are important both symbolically and ecologically. They are one of the last survivors of an ancient group of salamanders—the loss of this species would mean the loss of a genus and the only members of its family that occurs in North America. They are important predators of crayfish, and while detailed studies are lacking, they likely play a role in keeping crayfish populations in control in streams.

Hellbenders are declining across their range and are petitioned for listing under the Endangered Species Act. To date, the southern Blue Ridge Mountains contain some of the best Hellbender populations remaining, yet there are still many historic sites where Hellbenders cannot reliably be found or are found at low densities.

Hellbenders are primarily threatened by river sedimentation and pollution that are causing declines of suitable habitat for these animals. Soil erosion leads to increased silt and sediment in rivers. Siltation leads to spaces being filled in along stream bottoms; therefore, Hellbenders cannot go under rocks for refuge, nests get filled in and larvae lack spaces in the stream bottom that are critical for survival at that young age. Increased erosion also tends to lead to increased pollutants into rivers that Hellbenders may absorb directly through their skin, and it reduces the dissolved oxygen in the water which is essential for them to breathe.

Dams and other alterations to rivers have also reduced habitat suitability for Hellbenders, not only by creating barriers to movement, but more importantly, by creating stretches of river that no longer have the flow necessary to maintain Hellbender populations. This eliminates habitat and isolates populations. Humans also exert some direct pressure on Hellbenders—for example, river recreation often leads to rocks that Hellbenders use being moved around, and humans will sometimes kill Hellbenders based on misconceptions and fear. Disease could also be a factor, although there is not yet direct evidence for this.

These threats are affecting Hellbender ecology. Survival rates of Hellbenders to adulthood are extremely low, so even small changes in their environment can cause them to not only lose their habitat, but it can also result in troubled breathing due to low oxygen levels and slow river flow. Many sites still have older adult Hellbenders but lack larvae or young individuals. Such patterns suggest that Hellbenders are most vulnerable at these early stages, and improving survival of young Hellbenders may be the most important conservation action. Hellbenders also probably have limited ability to respond or adapt to disturbance as they have very low levels of movement. It’s imperative that we work to conserve these microhabitats so that more Hellbenders are able to survive to adulthood and to reproductive age.

 

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