The North American Beaver (Castor canadensis) is Recolonizing the Llano Estacado

Abstract

Five millennia ago, the North American beaver (Castor canadensis) was extirpated from the Southern High Plains by droughts. Beaver were found to be largely absent from the Llano Estacado, despite exhaustive search efforts. Here we report the first definitive evidence of an extant C. canadensis population recolonizing the Llano Estacado. We further provide some spatiotemporal background information about beaver colonization along the North Fork of the Double Mountain Fork of the Brazos River.

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*Corresponding author: G.D.Langlois@gmail.com
190
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The North American beaver (Order: Roden-
tia, Family: Castoridae, Castor canadensis Kuhl,
1820) is the largest extant rodent native to
North America (Hazard 1982). Beavers are
semiaquatic, and their habitation along streams
is generally conspicuous: family groups con-
struct burrows, canals, dams, and lodges (Berry
1923, Jackson 1961). Beaver dams are iconic
for creating vital wetland habitat by impound-
ing water. For that reason, the beaver is a
keystone species that engineers ecosystems,
affecting natural communities disproportion-
ately greater than would be expected relative
to its local abundance (Rosell et al. 2005, Bra-
zier et al. 2021, Wohl 2021).
The fossil record revealed that C. canaden-
sis (hereafter beaver) occurred in north-central
Texas less than 125,000 BP (Dalquest 1962).
Further evidence of range expansion by south-
western beavers includes fossil remains at the
New Mexico–Mexico border (Harris 1993) and
in northwestern Arizona (Jass 2002). Beaver
colonization of semiarid and arid landscapes
(e.g., the American Southwest) was almost
certainly achieved through a vast network of
beaver-dammed streams (Wohl 2021). Follow-
ing 2 extensive droughts 6500–4500 BP (Holli-
day 1985), beavers were extirpated from the
Southern High Plains (Bolen and Flores 1986,
Bolen et al. 1989). No evidence of recoloni -
zation from neighboring escarpments, nor of
an extant beaver population, was reported in
1831–1832 (Pike 1969), 1986 (Bolen and Flo-
res 1986), 1989 (Bolen et al. 1989), 1994 (Haukos
and Smith 1994), or 2003 (Baker and Hill
2003). Further into the 21st century, beavers
were still considered absent from the Llano
Estacado, save Randall County in northwest-
ern Texas (Schmidly and Bradley 2016, iNatu-
ralist contributors and iNaturalist 2021a).
On 4 November 2015, the carcass of an
adult beaver (accession number of skull: TTU-
M 128469) was found on the bank of Canyon
Lake 5 in Mackenzie Park (33°3524.3 N,
101°4949.9 W), Lubbock, Texas (Garcia et al.
2016). The Canyon Lakes are a series of 6
narrowly constructed lakes, considered rela-
tively drought proof (HDR Engineering, Inc.
2018) because a substantial portion of their
inflow is reclaimed municipal effluent (Winn
Western North American Naturalist 82(1), © 2022, pp. 190–195
The North American beaver (Castor canadensis)
is recolonizing the Llano Estacado
GARRET D. LANGLOIS1,*, ROBERT D. COX1, PHILIP S. GIPSON1, AND RICHARD D. STEVENS1,2
1Department of Natural Resources Management, Texas Tech University, Lubbock, TX 79409
2Natural Science Research Laboratory of the Museum, Texas Tech University, Lubbock, TX 79409
ABSTRACT.—Five millennia ago, the North American beaver (Castor canadensis) was extirpated from the Southern
High Plains by droughts. Beaver were found to be largely absent from the Llano Estacado, despite exhaustive search
efforts. Here we report the first definitive evidence of an extant C. canadensis population recolonizing the Llano Esta-
cado. We further provide some spatiotemporal background information about beaver colonization along the North Fork
of the Double Mountain Fork of the Brazos River.
RESUMEN.—Hace cinco milenios, el castor norteamericano (Castor canadensis) fue extirpado de las Altas Llanuras
del Sur por las sequías. Se encontró que los castores estaban en gran parte ausentes del Llano Estacado, a pesar de los
exhaustivos esfuerzos de búsqueda. Aquí reportamos la primera evidencia definitiva de una población existente de
C. canadensis recolonizando el Llano Estacado. También proporcionamos información de antecedentes espacio-temporal
sobre la colonización de castores a lo largo del North Fork del Double Mountain Fork del río Brazos.
GDL  orcid.org/0000-0001-8498-0891

1973). This lake system follows the North
Fork of the Double Mountain Fork of the
Brazos River, an intermittent stream which
runs through Yellow House Canyon (Winn
1973). The occurrence of that specimen in
Canyon Lake 5 was considerably disjunct from
the known range of beaver in the Panhandle
Plains (Garcia et al. 2016, Schmidly and Bradley
2016). Garcia et al. (2016) speculated that the
specimen had not been anthropogenically
translocated but arrived alive and under its
own power, likely during the high waters of
summer 2015 via eastern ingress. No further
evidence of beaver was presented beyond that
single carcass.
Southeast from Canyon Lake 5 is Canyon
Lake 6, and the parks of Mae Simmons and
Dunbar Historical Lake, in that order. Mae
Simmons is a 98.3-acre seminatural recrea -
tional park, and one of the more wooded sites
along the Canyon Lakes system. We classified
the seminatural portions of the park into 4
ecological map units of the High Plains ecore-
gion (Elliott et al. 2014). The southwestern
lakeshore was riparian hardwood forest, which
contained eastern cottonwood (Populus del-
toides) and black willow (Salix nigra) tree
species. Southwest of the riparian hardwood
forest was a depressional marsh, a natural
community distinct from the closed wetland
system of a playa. Floodplain hardwood forest
grew surrounding the depressional marsh and
adjacent to the riparian hardwood forest. Fur-
ther upland was shortgrass prairie. Consider-
ing these habitat types and the natural history
of beavers, we hypothesized that if beaver
could occur in the Canyon Lakes, they would
do so in Mae Simmons Park.
In January 2018, we discovered chewed
stumps from 1 to 3 seasons past, along the
shoreline of Canyon Lake 6 in Mae Simmons
Park (33°3439.7 N, 101°4934.1 W). A pattern
of fresh evidence appeared in the following
weeks and into spring (Fig. 1). Encouraged
by signs of potential beaver habitation, we
conducted water quality analyses to confirm
the suitability of the lakewater for beaver
(Table 1). On 30 March 2018, we deployed 3
motion-activated trail cameras (Bushnell Tro-
phy Camera Brown Model 119537, Bushnell
LANGLOIS ET AL. ♦ BEAVER ARE RECOLONIZING LLANO ESTACADO 191
Fig. 1. A tetraptych of beaver signs observed along the western shoreline of Canyon Lake 6, at Mae Simmons Park,
Lubbock, Texas. Images are ordered chronologically by date of discovery. The freshly chewed limbs of a felled black
willow (Salix nigra) and extensive beaver trails were observed on 14 February 2018 at 33°3434.1 N, 101°4928.1 W. We
observed chewed, then charred, stumps from 1 to 3 seasons past on 21 March 2018 at 33°3430.2 N, 101°4923.5 W.
Finally, we observed freshly chewed stumps (U.S. penny for scale) on 19 April 2018, again at 33°3434.1 N,
101°4928.1 W. These conspicuous signs were clear indicators of beaver activity (Wade and Ramsey 1986). Additionally,
on 1 February 2018, we conversed with a local angler who provided a descriptive account of beaver activity. He claimed
to have occasionally observed beavers in June, July, and August of 2017, between 00:00 and 01:00. He stated that the
beaver were traveling downstream from Canyon Lake 5, out of the culvert under U.S. Highway 62 (33°3440.5 N,
101°4933.6 W) and into Canyon Lake 6.

Corp., Overland Park, Kansas, USA). We cap-
tured images and video until 30 July 2018.
With permission from the Lubbock Parks and
Recreation Department, trail cameras were
placed in discreet, off-trail locations and pro-
grammed to only activate at night. Using these
cameras, we documented a pair of beavers on
8 July 2018 (Fig. 2, Supplementary Material 1).
Having confirmed the presence of beaver
in the Canyon Lakes, we then examined the
hypothesis of upstream colonization from the
east. Between Canyon Lakes 5 and 6, the con-
fluence of Yellow House Draw and Blackwa-
ter Draw merge, forming the headwaters of
the North Fork of the Double Mountain Fork
of the Brazos River. Downstream and south-
east, the North Fork merges into the Double
Mountain Fork of the Brazos River. Assuming
riverine dispersal for immigrating beaver, we
calculated the North Fork river length to be
146.5 km (USGS Texas Water Science Center
2016). Average riverine dispersal distances for
beaver have been reported to be 7.3 km (Weaver
1986), 7.7 km (Van Deelen and Pletscher 1996),
and 4.6 km (DeStefano et al. 2006). Long-
distance riverine dispersal is possible; an adult
beaver was found to have traveled 238 km
(Hibbard 1958).
We gathered credible reports of local
beaver encounters to provide spatiotemporal
background about beaver colonization along
this watercourse. Downstream from Canyon
Lake 6, a beaver was photographed below
the Buffalo Springs Lake dam on 7 May 2011
(Dr. K. Griffis-Kyle, personal communication,
20 September 2021; Supplementary Material 2).
Further southeast is Lake Alan Henry, con-
structed along the Double Mountain Fork of
the Brazos River. The reservoir dam is a linear
distance of 5.9 km from the confluence of the
North Fork and the Double Mountain Fork. A
maintenance log entry from 15 April 2009
recorded that a recently arrived beaver colony
had dammed the lake outflow conveyance
channel, which was cleared that day. Those
beavers relocated to a den in the spillway
stilling basin for the summer, after which they
were not observed again (M.A. Record, per-
sonal communication, 27 September 2021).
These reports support the hypothesis of
upstream riverine immigration, likely from
the Brazos River in north-central Texas.
Given that the combined river length of the
North Fork and Double Mountain Fork is
375 km (USGS Texas Water Science Center
2016), there are almost certainly other beaver
colonies established along that watercourse.
This pioneering population could have long
gone unreported, given that we only recently
confirmed that beaver have been cryptically
colonizing the North Fork for at least the last
decade.
The return of beaver to the Llano Estacado
after an absence of several millennia is sig -
nificant. This colonization also ushers in the
type of human–wildlife challenges that can
arise when the public are unaccustomed to a
novel animal on the landscape. The public and
these beavers have already begun to interact,
and some of the beavers have unfortunately
become victims of road mortality (iNaturalist
contributors and iNaturalist 2021b). Monitor-
ing this new population would be advisable to
best mitigate potential human–beaver con-
flicts. This effort could be achieved taxpayer
free, as we anticipate broad and enduring
community-based enthusiasm for such a proj -
ect. Long-term monitoring of these beavers
192 WESTERN NORTH AMERICAN NATURALIST (2022), VOL. 82 NO. 1, PAGES 190–195
TABLE 1. Physicochemical characteristics of water samples collected on 20 March and 24 April 2018 from Canyon
Lake 6, at Mae Simmons Park, Lubbock, Texas. Collection sites were shoreline locations of both active beaver use
(33°3434.1 N, 101°4928.1 W) and past beaver use (33°3430.7 N, 101°4916.1 W). Each test was conducted 4 times;
we are reporting the average. Water quality metrics were either within the range of what King (1983) reported for this
lake system or sufficiently close that the difference was explainable by variation in sampling site and season.
Water sample collection sites
______________________________________
Water quality metric Active beaver use Past beaver use Unit of measurement
Turbidity 20 20 JTU
Acidity 7.5 8.0 pH
Alkalinity 304 278 mg/L CaCO3
Ammonia 0.39 0.15 mg/L NH4−N
Nitrates 0.0 0.0 mg/L NH3−N
Phosphorus 0.14 0.11 mg/L PO43−
Dissolved oxygen 1.4 7.0 mg/L SaO2

could be conducted by volunteers and engage
municipal educators and local naturalists, both
young and old alike.
Ultimately, we assert there are more bene-
fits than drawbacks in the recolonization of the
Llano Estacado by beaver. These beavers will
enhance habitat for semiaquatic furbearers and
other mammals, waterfowl and other birds,
amphibians, reptiles, fish, and pollinating in -
sects. Especially considering that Lubbock will
expand the Canyon Lakes system with the
addition of Canyon Lake 7—a 774-acre lake
LANGLOIS ET AL. ♦ BEAVER ARE RECOLONIZING LLANO ESTACADO 193
Fig. 2. On 8 July 2018, our trail camera captured images and video of beaver activity. A pair of beavers were swim-
ming at the mouth of a rheocrene spring-fed brook (33°3434.5 N, 101°4929.3 W), which empties into Canyon Lake 6,
at Mae Simmons Park, Lubbock, Texas. Previously, on 24 June 2018 at 21:30, we had observed a beaver swimming at
this same site. Additionally, on 19 June 2018 between 21:30 and 22:30, we observed a beaver swimming at the southeast
corner of Canyon Lake 6, 8–20 m northwest of the Dunbar Lake dam (33°3357.7 N, 101°4806.8 W).

slated to cost $251 million and to be com-
pleted by the year 2040 (HDR Engineering,
Inc. 2018, Texas Water Development Board
2020). Expansions of the Canyon Lakes will
very likely be colonized by this pioneering
population of beaver. This is a conservation
opportunity of mutual benefit for both beaver
and the residents of the Southern High
Plains. On rangeland where beavers have
been restored, beaver dams can lengthen sea-
sonal streamflows, raise groundwater levels,
reduce streambank incision and erosion, con-
trol flooding, improve surface water flows,
enhance resilience to drought and wildfire,
increase biodiversity, improve aquatic and
riparian habitat, and hasten groundwater and
well-water recharge rates (Charnley 2018,
2019, Kantor and Charnley 2020, Wohl 2021).
If granted the opportunity, beavers could ful-
fill their role as low-cost ecosystem restora-
tion engineers of the Llano Estacado, which
we suggest is worth consideration.
SUPPLEMENTARY MATERIAL
Two online-only supplementary files accom-
pany this article (https://scholarsarchive.byu
.edu/wnan/vol82/iss1/20).
SUPPLEMENTARY MATERIAL 1. On 8 July 2018,
our trail camera captured a pair of beavers swim-
ming at the mouth of a rheocrene spring-fed
brook, which empties into Canyon Lake 6, at Mae
Simmons Park, Lubbock, Texas (mp4 video, 11 s).
SUPPLEMENTARY MATERIAL 2. Downstream from
Canyon Lake 6, a beaver was photographed below
the Buffalo Springs Lake dam on 7 May 2011.
Observation was made by Sean Kyle and Dr. Kerry
Griffis-Kyle.
ACKNOWLEDGMENTS
We are grateful for the interdisciplinary
collaboration with artists David Chapman
Lindsay and Stephanie Rae Berrie. We appre-
ciate the field support of Matthew R. Jackson
and Robert C. Lee. We are thankful for the
laboratory supplies and support provided by
Drs. Mark C. Wallace and Matthew A. Barnes.
We thank the Lubbock Parks & Recreation
Department for facilitating site use and record
acquisition, especially Dr. Lionel Plummer,
Diane Selby, and Mark Record. Sean Kyle and
Dr. Kerry Griffis-Kyle provided the Buffalo
Springs Lake beaver photograph, which was
most helpful. Lastly, we enjoyed interacting
with the many friendly and helpful citizens
of Lubbock, who approached us with good-
natured curiosity while we were in the field.
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