A Previously Undocumented Locality of Eastern
Hellbenders (Cryptobranchus alleganiensis alleganiensis) in the Elk River, Carter County, TN
M. Worth Pugh, John D. Groves, Lori A. Williams, and Michael M. Gangloff
Southeastern Naturalist, Volume 12, Issue 1 (2013): 137–142
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2013 SOUTHEASTERN NATURALIST 12(1):137–142
A Previously Undocumented Locality of Eastern
Hellbenders (Cryptobranchus alleganiensis alleganiensis) in
the Elk River, Carter County, TN
M. Worth Pugh1,*, John D. Groves2, Lori A. Williams3, and Michael M. Gangloff1
Abstract - Cryptobranchus alleganiensis alleganiensis (Eastern Hellbender) is a large,
imperiled aquatic salamander found in rocky upland streams from New York to Alabama.
Although widespread, many Hellbender populations are now highly fragmented by impoundments
and degraded habitats. Hellbenders likely require specific stream habitats
with relatively low anthropogenic impacts in order to maintain population viability. The
Elk River is a small (5th order), high-gradient tributary of the Watauga River drainage that
originates in Avery County, NC and flows northwest to Watauga Reservoir in northeastern
Tennessee. Although the Elk River’s headwaters are heavily impacted by development in
the resort towns of Banner Elk and Sugar Mountain; its lower reaches flow through portions
of the Pisgah and Cherokee National Forests and over several large waterfalls before
reaching the reservoir. Hellbender presence was undocumented in the Elk River prior to
2010. We learned that Hellbenders were likely present in the lower Elk River from anecdotal
reports of sightings in Tennessee. In 2010 and 2011, we surveyed for Hellbenders at 10
sites in the Elk River drainage. We observed multiple size classes, including larvae and juveniles,
present in the lower Elk River. Development in headwater regions of the Elk River
in North Carolina may have caused habitat degradation in the upper Elk River causing the
extirpation of Hellbenders in the upper reaches.
Introduction
Cryptobranchus alleganiensis Daudin (Hellbender) is a species of large
aquatic salamander endemic to the Appalachian and Ozark Mountains. Two
subspecies are currently recognized, C. a. bishop Grobman (Ozark Hellbender)
and C. a. alleganiensis (Eastern Hellbender), both of which are considered imperiled
(Briggler et al. 2007a, Mayasich et al. 2003, Petranka 1998, Sabatino and
Routman 2009). Adult Hellbenders are typically found under large rocks in highquality,
fast-flowing, upland streams (Dundee and Dundee 1965, Hillis and Bellis
1971, Smith 1907). Larval encounters during surveys are rare, possibly because
(1) larvae have high mortality rates (and are thus uncommon); (2) larvae utilize
habitats that are difficult to search effectively (e.g., stream margins, aquatic
macrophytes, and interstitial areas in gravel); or (3) survey methods do not target
larval habitat (Nickerson and Krysko 2003). Conversely, some sites yield larval
encounters regularly though not usually in large quantities (Nickerson and Mays
1973; Nickerson et al. 2003; Petranka 1998; M.W. Pugh, unpubl. data).
The Ozark sub-species is restricted to the Ozark Mountains of Arkansas and
Missouri and is listed by the US Fish and Wildlife Service as an endangered species
1Department of Biology, Appalachian State University, 572 River Street Boone, NC
28608-2027. 2North Carolina Zoological Park, 4401 Zoo Parkway, Asheboro, NC 27205.
3North Carolina Wildlife Resources Commission, 177 Mountain Laurel Lane, Fletcher,
NC 28732. *Corresponding author - mp74446@appstate.edu.
138 Southeastern Naturalist Vol. 12, No. 1
(USFWS 2011). The Eastern Hellbender occurs across a much broader range from
southern New York to northern Alabama and central Missouri (Petranka 1998).
Although the Eastern subspecies is still widely distributed, many populations have
undergone significant declines (Briggler et al. 2007b, Wheeler et al. 2003), including
possible extirpation in Alabama streams (Graham et al. 2011). The Eastern
Hellbender is not federally protected, so the sub-species’ conservation status is
determined by state governments (Briggler et al. 2007, Mayasich et al. 2003). In
North Carolina, the Eastern Hellbender is considered a species of concern which
are protected from being killed, harassed, harmed, or illegally collected and are
considered a priority species (NCWRC 2005). Tennessee lists Eastern Hellbenders
as a species in need of management (Mayasich et al. 2003).
Historically, Hellbenders were abundant in upland streams throughout the Eastern
and Central United States (Nickerson and Mays 1973). During the 20th century,
many Hellbender populations declined dramatically (Briggler et al. 2007b, Mayasich
et al. 2003, Petranka 1998, Wheeler et al. 2003). Most researchers conclude
that these declines are attributable to land-use change causing habitat degradation,
stream impoundment, removal of riparian flora, stream channelization, siltation,
and pollution (Briggler et al. 2007b, Nickerson et al. 2003, Petranka 1998, Sabatino
and Routman 2009, Wheeler et al. 2003). There have also been instances of
illegal collection for the pet trade as well as deliberate killing of Hellbenders due
to the mistaken belief that they are “poisonous” and primarily consume large percentages
of game fish and their eggs (Nickerson and Briggler 2007, Nickerson and
Mays 1973).
A number of biotic factors may exacerbate Hellbender declines including introduced
predatory fish (i.e., Salmo trutta L. [Brown Trout]) and Oncorhynchus
mykiss Walbaum [Rainbow Trout]; Crane and Mathis 2010, Gall and Mathis 2010),
reduced prey items (primarily crayfish; Nickerson and Mays 1973, Nickerson et
al. 2003), and presence of parasites, disease, or fungal infection including amphibian
chytrid fungus (Batrachochytrium dendrobatidis Longcore; Briggler et al.
2007a, Nickerson et al. 2011). Extirpation of Hellbenders from streams may have
profound effects on ecosystem structure and function because they play significant
ecological roles as predators and prey throughout their life cycle (Humphries and
Pauley 2005, Nickerson and Mays 1973, Smith 1907). Moreover, because stable
Hellbender populations are usually associated with high-quality freshwater ecosystems
they are indicators of stream health (Petranka 1998). Thus, detection of
isolated populations provides insight on local water-quality conditions as well as
baseline population data that may be critical when planning future conservation
strategies. Here we report two previously unknown localities and a verification of
anecdotal reports of Eastern Hellbenders in the Elk River, TN.
Methods
Surveys were conducted in 7 sites within the Elk River in Avery County, NC
and Carter County, TN. Detailed site localities are not disclosed to minimize
risk of illegal collections. However, all locality and demographic data have been
provided to the US Forest Service, the Tennessee Wildlife Resources Agency,
and the North Carolina Wildlife Resources Commission. We conducted searches
2013 M.W. Pugh, J.D. Groves, L.A. Williams, and M.M. Gangloff 139
for Hellbenders using rock-turning surveys with the aid of log peaveys and mask
and snorkel (Nickerson and Krysko 2003). During these surveys in summers
2010 and 2011, we captured 25 individuals (21 adults, 2 juveniles, and 2 larvae)
from three localities in the Elk River. We measured length (TL and SVL) and
mass, determined sex, and noted physical abnormalities for all specimens. In the
second year of surveys, we began tagging animals using passive integrative transponder
(PIT) tags (BioMark©) for adults and visible implant elastomers (VIE)
for larvae (Northwest Marine Technology Inc.). Hellbenders were classified by
3 separate size classes. We classified larvae as Hellbenders possessing free gills.
Hellbenders that no longer exhibited free gills but were less than 22cm in TL
were considered juveniles, and any Hellbender with a TL exceeding 22 cm was
considered an adult (Nickerson and Mays 1973).
Results and Discussion
The sex ratio was skewed toward males (14:7). We could not determine
sex for 2 juvenile and 2 larval Hellbenders. Peterson et al. (1983) and Taber et
al. (1975) used linear regression to create age-length growth curves for Hellbenders.
Both studies found that Hellbenders grow slowly particularly after
metamorphosis. However, no studies have yet quantified long-term Hellbender
growth rates. Using TL from all captures, we created a histogram of Hellbender
size-classes that we present as a representation of multiple age-classes
(Fig. 1). These data suggest this population, although geographically isolated,
may still be reproductively viable.
Figure 1. Total-length distribution of Hellbenders captured in the Elk River, 2010 and 2011.
140 Southeastern Naturalist Vol. 12, No. 1
Though one of the localities was a verification of anecdotal reports of Hellbenders,
the species had not been documented in the Elk River prior to our surveys
(Redmond and Scott 2011). We are aware of only one previous Hellbender survey
targeting the Elk River. The North Carolina Wildlife Resources Commission and
the North Carolina Zoo surveyed 2 locations in the Elk River in Avery County, NC
in 2009 but did not capture or encounter any Hellbenders (J.D. Groves and L.A.
Williams, unpubl. data). Surveys in the upper Elk River revealed habitats that appear
suitable for Hellbenders (i.e., abundance of large stream particles with large
cavities, numerous prey items, clear fast-flowing water) (Dundee and Dundee
1965, Hillis and Bellis 1971, Smith 1907). Nonetheless, much of the upper Elk
River had what we would characterize as poor habitat (i.e., low substrate heterogeneity
and stability, no interstitial space, embedded particles; Nickerson and Mays
1973). These observations suggest that Hellbenders may be extirpated or never occurred
in the upper Elk River. Local land use appeared important to Hellbenders in
the lower Elk River. Surveys at 2 sites with intensive riparian disturbance (road-bed
encroachment and stabilization, residential dwellings) resulted in few Hellbenders
(n = 2). In contrast, surveys at a remote site with high percentages of vegetative cover
within riparian zones produced the vast majority of captures (n = 23). Regardless,
there are sections of the Elk River which are privately owned which we were not
granted access to so there is still the possibility that Hellbenders still persist in parts
of the upper Elk River. We also recognize that Hellbenders exploit cryptic habitats
and can occupy cavities of boulders and bedrock where field technicians cannot
reach and some stream particles in the sites were too large to lift.
One hypothesis, which would explain the absence of Hellbenders in the upper
Elk River, is that human-mediated water-quality impairment led to the extirpation
of Hellbenders. The species’ extreme sensitivity to poor habitat and water
quality possibly caused Hellbenders to migrate to less-afflicted stretches of the
Elk River. Presence of heavy metals (i.e., Co, Cd, Cr, Pb, Hg; Huang et al. 2010)
or excessive levels of pesticides and fertilizers from current or previous land use
in the region (Freake and Lindquist 2008) may have contributed to Hellbender
extirpations in the upper Elk River. Large falls exist on the Watauga River, and
Hellbenders have colonized much of the upper reaches of this sub-watershed.
However, Ball (2001) found that Hellbenders in the Watauga River exhibit little
if any within-stream migration, suggesting that Hellbender dispersal rates are
very low. Although large waterfalls (>15 m) on the Elk River do not likely pose
an insurmountable barrier to Hellbenders, they may impede re-colonization of
the upper Elk River. An alternative hypothesis is that Hellbenders may have been
unable to colonize the Elk River upstream from the falls and never occurred in
the upper Elk River. However, in September of 2011, we received an anecdotal
report and picture of a captured Hellbender from two trout anglers suggesting
that there is at least one Hellbender in Cranberry Creek; a 1st order tributary of the
upper Elk River in North Carolina. If this observation is confirmed with specific
locality data, the alternative hypothesis is rejected. Continuing research will test
these hypotheses by investigating the linkages between stream physiochemical
habitat parameters and Hellbenders, providing empirical population estimates
(using mark-recapture) for the Elk River and Watauga River drainage, map dis2013
M.W. Pugh, J.D. Groves, L.A. Williams, and M.M. Gangloff 141
tributions of hellbenders in the Elk River, and assess the effect of local land use
on populations of this increasingly rare aquatic salamander.
The discovery of previously unrecognized populations is important to
Hellbender management because it suggests that other undocumented populations
may persist in remote, high-quality streams in the southern Appalachian
Mountains. Recent phylogenetic analysis using mitochondrial DNA documented
extensive cryptic diversity in Hellbenders (as much as 5.7% divergence; Sabatino
and Routman 2009). Isolated populations, such as the Elk River, may contain
unique elements of genetic or behavioral diversity, which would increase understanding
of Hellbender phylogeography and possibly enhance the success of
propagation or population augmentation efforts in this region.
Acknowledgments
We thank the United States Department of Agriculture Forest Service, the Tennessee
Wildlife Resources Agency, and the North Carolina Wildlife Resources Commission for
permits and historical data. Funding for J.D. Groves was provided by North Carolina Zoo
Society. Floyd Scott of Austin Peay State University confirmed the new record for the Elk
River. Lynn Siefferman provided advice and criticism. Russ Bryant, Marcia Carter, Sara
Conway, Andrea Engle, Michael Freake, Byron Hamstead, Jordan Holcomb, Blair Joyal,
Danielle Moore-Thomas, Katie Rifenburg, Caylor Romines, Thomas Scott, Lynn Siefferman,
Jason Selong, Bradley Skinner, David Strickler, Jonathan Thomas, and Jackie
Wagner assisted with fieldwork. Without the assistance of the agencies and individuals
listed above this project would not have been possible.
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