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22001188 SOUTHEASTERN NATURALIST 1V7o(2l.) :1275,7 N–2o6. 92
Habitat Associations of Three Crayfish Endemic to the
Ouachita Mountain Ecoregion
Joseph J. Dyer1 and Shannon K. Brewer2,*
Abstract - Many crayfish are of conservation concern because of their use of unique
habitats and often narrow ranges. In this study, we determined fine-scale habitat use by
3 crayfishes that are endemic to the Ouachita Mountains, in Oklahoma and Arkansas. We
sampled Faxonius menae (Mena Crayfish), F. leptogonopodus (Little River Creek Crayfish),
and Fallicambarus tenuis (Ouachita Mountain Crayfish) from wet and dry erosional channel
units of 29 reaches within the Little River catchment. We compared channel-unit and microhabitat
selection for each species. Crayfish of all species and life stages selected erosional
channel units more often than depositional units, even though these sites were often dry.
Accordingly, crayfish at all life stages typically selected the shallowest available microhabitats.
Adult crayfish of all species and juvenile Little River Creek Crayfish selected patches
of coarse substrate, and all crayfish tended to use the lowest amount of bedrock available.
In general, we showed that these endemic crayfish used erosional channel units of streams,
even when the channel units were dry. Conservation efforts that protect erosional channel
units and mitigate actions that cause channel downcutting to bedrock would benefit these
crayfish, particularly during harsh, summer drying periods.
Introduction
Approximately 80% of the world’s crayfish species occur in North America (Taylor
et al. 2007), and crayfish diversity is highest in the southeastern US (66% of North
American crayfishes; Simon 2011). These species are often endemic to portions of
small ecoregions, making them exceptionally vulnerable to human stressors (e.g.,
habitat destruction, habitat loss, and pollution; Simon 2011, Taylor et al. 2007).
Even as new species are still being described (e.g., Jones 2016, Schuster et al. 2015,
Thoma and Fetzner 2015), our knowledge of previously documented species remains
limited, making monitoring and conservation efforts for these endemic populations
difficult and often reactive (Loughman and Fetzner 2015, Simon 2011).
The Ouachita Mountain ecoregion is home to several endemic crayfishes, including
4 stream-dwelling species in Oklahoma. Faxonius saxatilis (Bouchard and
Bouchard) (= Orconectes saxatilis) (Kiamichi Crayfish; Crandall and De Grave
2017) occurs only in the upper reaches of the Kiamichi River, where it primarily
occupies riffles despite seasonal intermittence of the streams (Jones and Bergey
2007). When streams become intermittent, Kiamichi Crayfish burrow into the
moist substrate under boulders and cobbles in the riffles to avoid desiccation (Jones
1Oklahoma Cooperative Fish and Wildlife Research Unit, Oklahoma State University,
Stillwater, OK 74074. 2US Geological Survey, Oklahoma Cooperative Fish and Wildlife
Research Unit, Oklahoma State University, Stillwater, OK 74074. *Corresponding author -
shannon.brewer@okstate.edu.
Manuscript Editor: Bronwyn Williams
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and Bergey 2007). Jones and Bergey (2007) also collected Fallicambarus tenuis
(Hobbs) (= Procambarus tenuis) (Ouachita Mountain Crayfish; Ainscough et al.
2013, Crandall and De Grave 2017), but it was too rare to include in their habitat
analysis. However, this species was found to occupy small (1st and 2nd order; Strahler
1957) spring-fed streams and cool, clear perennial streams, where it excavates shallow,
simple burrows or seeks shelter under rocks (Jones and Bergey 2007, Robison
and McAllister 2008). Faxonius leptogonopodus (Hobbs) (= O. leptogonopodus)
(Little River Creek Crayfish; Crandall and De Grave 2017) and F. menae (Creaser)
(= O. menae) (Mena Crayfish; Crandall and De Grave 2017) habitats are typically
small to medium, clear, permanent streams with swift flow and rocky substrates
(Robison et al. 2009, Williams 1954).
Our study broadens the knowledge of habitat associations of 3 of the aforementioned
species (Ouachita Mountain Crayfish, Little River Creek Crayfish, and
Mena Crayfish) by investigating habitat use at fine spatial scales (i.e., channel unit
and microhabitat). Jones and Bergey (2007) documented habitat associations of the
Kiamichi Crayfish in the Kiamichi River catchment, and we did not repeat their
efforts. Instead, we focused our sampling efforts in the adjacent Little River catchment
where the other 3 species are distributed (Dyer et al. 2013). We compared
observed habitat use to habitat availability at both the channel unit (e.g., erosional
and depositional) and microhabitat scales. Knowledge of habitat use at multiple
spatial scales allows managers to focus conservation efforts in areas where suitable
habitat naturally occurs and can be protected or rehabilitated.
Methods
Study area
We conducted crayfish sampling in the Little River catchment of the Ouachita
Mountain Ecoregion, OK (Fig. 1). Dominant lithology of the Little River catchment
is sandstone and shale (Woods et al. 2005). The landscape vegetation is a mixture
of hardwood and coniferous forest, and land-use practices include recreation (e.g.,
horseback riding), logging, and poultry or cattle agriculture. The Ouachita National
Forest is located in the northeast portion of the catchment, encompassing much of
the headwaters of the Mountain Fork River. Ouachita National Forest streams are
somewhat protected from the effects of agriculture and industrial timber-harvest
practices (Woods et al. 2005).
Field sampling
During summer 2011 and 2012, we sampled 29 study reaches that comprised a
series of erosional and depositional channel units. We defined each sample reach
as a length of stream with 3 pool–riffle sequences. In each reach, we sampled crayfish
from both erosional and depositional channel units. Erosional channel units
were characterized as having a swift current or steep streambed gradient relative
to adjacent habitat. Erosional channel units could be wet but were commonly dry
during our study. Depositional units had relatively slow-moving or stagnant water,
and were typically depressions in the streambed or pools, but also included some
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backwater and vegetated edges of the main channel. The channel units we sampled
were typically less than 10 m wide and ~5–30-m in length.
We quantitatively sampled crayfish using 1–3 haphazardly placed 1-m2 quadrat
samples (Dyer et al. 2016, modified from DiStefano et al. 2003) in both wet and
dry erosional and depositional channel units. Some sampled channel units were
relatively small, and we were only able to place a single quadrat in those locations,
whereas we took up to 3 quadrat samples in larger channel units. We did not take
multiple samples from channel units that were too small to accommodate them
without overlap. We placed the quadrat sampler haphazardly within each channel
unit. In wetted channel units, we employed a quadrat sampler with 3-mm mesh and
a 0.5 m x 1 m x 1.2 m downstream bag to sample crayfish (see figure 2 of Dyer et
al. 2016). After placement of the quadrat, we removed coarse particles within the
quadrat sampler. Any remaining substrate in the quadrat was disturbed to a depth of
15 cm as water was swept into the downstream bag. We sampled dry-channel units
by delineating 1-m2 plots within each channel unit and excavated and searched for
crayfish to a depth of 30 cm in the substrate within plots (DiSt efano et al. 2009).
We measured microhabitat parameters at each quadrat-sample location prior to
sampling to represent unaltered habitat conditions. We visually classified substrate
Figure 1. Crayfish sampling locations:
Solid circles indicate sites where we
detected 1 of our species of interest and
open circles indicate sites where none of
our species of interest were detected. We
conducted our sampling in the Ouachita
Mountain Ecoregion of Oklahoma (from
west to east, the mainstem rivers are
Little, Glover, and Mountain Fork rivers).
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using the modified Wentworth scale (Cummins 1962). In each quadrat, we estimated
the percent cover of each of 4 substrate categories: bedrock (solid, mostly
subterranean shale or sandstone), coarse substrate (>64 mm), gravel (4–64 mm),
and fine substrate (less than 4 mm). We measured depth (to the nearest 1.0 cm) and employed
an electromagnetic flow-meter (Model 2000 Portable Flow Meter; Marsh–
McBirney, Fredrick, MD) to determine average water-column velocity (at 0.6 of
depth to the nearest 0.1 m s-1) in the center of each quadrat.
We identified captured crayfish to species and measured carapace lengths
(CL) to determine life stage. We used vernier calipers to measure the carapace—
from anterior tip of the rostrum to the posterior edge of the carapace—to the
nearest 0.5 mm. We completed preliminary sampling in November and December
2012 to determine the CL of both juveniles and adults. We used the smallest CL of
Form I males of each species to delineate the CL of juveniles. We determined that
individuals of all species with a CL of ≥17 mm were adults, and individuals with
a CL of less than 17 mm were juveniles. However, juvenile Ouachita Mountain Crayfish
were rare in our samples, so we did not differentiate adult and juvenile life stages
for that species.
Selected habitat
We determined available habitat at both the channel unit and microhabitat scales
for each reach at the time of sampling. We mapped erosional and depositional
channel units at each site. We considered channel units available to each species if
the species occupied that sampling reach. In our analysis, if a species occurred in
10 sample reaches, we considered the sum of channel-unit habitat from those 10
reaches to be available. We treated available microhabitat similarly across all occupied
reaches, where availability included all microhabitats from reaches occupied
by a species. We determined microhabitat availability in each reach by summing
the microhabitat data collected from all quadrat samples combin ed.
We summarized habitat use and selection at the channel-unit and microhabitat
scales using descriptive statistics, graphical methods, and the Strauss selectivity index
(Strauss 1982). We calculated occurrence frequencies at the channel-unit scale
for the combined life stages of Ouachita Mountain Crayfish and adult and juvenile
Little River Creek Crayfish and Mena Crayfish. We calculated the Strauss selectivity
index as:
Li = ri - pi ,
where, ri is the proportion of the selected habitat represented by environmental parameter
i, and pi is the proportion of available habitat represented by environmental
parameter i. Positive or negative values indicate selection or avoidance; whereas,
values near zero represent neutrality. At the microhabitat scale, we created density
plots to compare the range of habitat conditions used relative to available habitat
(i.e., selection) in reaches where each species occurred. We did not calculate selectivity
indices for habitat features at this scale because we wanted to maintain
continuous data of each habitat element.
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Results
We collected at least 1 of the 3 species in 20 of the 29 stream reaches sampled
(Fig. 1). Little River Creek Crayfish was the most commonly encountered species;
285 individuals were collected from 11 reaches. Adult Little River Creek Crayfish
were much less abundant than juveniles, accounting for only 19% of the individuals
sampled. We sampled 103 Mena Crayfish from 9 reaches. Observed ratios of
adults to juveniles (1:2) were more balanced for Mena Crayfish compared to Little
River Creek Crayfish. Ouachita Mountain Crayfish was the rarest species; only 25
individuals were sampled from 6 reaches. We encountered adult Ouachita Crayfish
more frequently (68% of catch) than juveniles.
Crayfish of all species and life stages selected erosional channel units over
depositional channel units (Fig. 2). Juvenile Mena Crayfish and Little River Creek
Crayfish were sampled in at least half of all erosional channel units within reaches
where a member of either species was present. Similarly, adult Mena Crayfish and
Little River Creek Crayfish occurred in nearly half of the erosional units sampled
and were rare in depositional units. We found juveniles more commonly in depositional
channel units than adults, but juveniles still occupied erosional units twice
as often as depositional units. Ouachita Mountain Crayfish occurred exclusively
in erosional channel units. Our results suggest that erosional channel units are particularly
important to these species during the summer baseflow period, even when
surface flows cease.
Crayfish associations with water depth and bedrock were consistent among
species and life stages; however, associations with other substrates were more
variable. Crayfish were most frequently associated with the shallowest depths
Figure 2. Proportional use of
depositional (gray) and erosional
(white) channel units
by Faxonius leptogonopodus
(Little River Creek
Crayfish; FLE) and F. menae
(Mena Crayfish; FME) juveniles
(J) and adults (A), and
by all Fallicambarus tenuis
(Ouachita Mountain Crayfish;
FTE) sampled. The
values of the Strauss index
are listed above each bar.
Positive values indicate selection
and negative values
indicate avoidance.
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sampled (less than 14 cm) and areas with less than 10% bedrock (Figs. 3a, b; 4a, b; 5a, b). Adult and
juvenile Mena Crayfish occurred in all available depths, but generally at a slightly
lower frequency than expected based on availability when depths exceeded 25 cm
(Fig. 3). All species and life stages except juvenile Mena Crayfish were positively
associated with coarse substrate (Fig. 3c, 4c, 5c). Adult Mena Crayfish and all Little
River Creek Crayfish used gravel in proportion to availability, but juvenile Mena
Crayfish and Ouachita Mountain Crayfish tended to select moderate to higher proportions
of gravel (Figs. 3d, 4d, 5d). Fine substrate was rare in reaches where we
detected crayfish, and all crayfish used it in proportion to avai lability.
Discussion
We found that the 3 crayfishes frequently occurred in seasonally intermittent
streams. Like Kiamichi Crayfish (Jones and Bergey 2007), each species selected
erosional channel units over depositional channel units, and many of the erosional
channel units were dry. Similarly, DiStefano et al. (2009) found that densities of
F. williamsi (Fitzpatrick) (= Orconectes williamsi) (Williams’ Crayfish; Crandall
and De Grave 2017) in riffles did not differ as these areas dried, indicating that
crayfish sought refuge in the hyporheic zone rather than nearby pools. Likewise,
we found crayfish typically selected the shallowest available microhabitats. In
addition, crayfish typically used habitats with low amounts of bedrock or used
bedrock at or below available levels. Given our findings that crayfish in this study
selected dry, erosional habitats over wetted pools, the tendency to use areas with
greater portions of coarse substrate reflects their burrowing abilities (Dyer et al.
2015, Martin et al. 2012).
The selection of relatively dry habitats (i.e., erosional channel units) was
interesting given their close proximity to intermittent pools; however, the hyporheic
zone below the dry streambed likely offer refugia. One possible benefit of
the hyporheic refuge is thermal regulation (Dole-Oliver 2011, Wood et al. 2010).
Groundwater temperatures 20 cm below the surface are consistently cooler than
Figure 3 (following page). Density plots of habitat associated with the occurrence of Mena
Crayfish (gray lines) compared to the available habitat (black lines) in reaches where we
encountered the species. The area under each curve accounts for 100% of the observations
and the dashed vertical lines represent the median value associated with used (gray)
and available (black) habitat. Each panel represents a different environmental parameter:
(a) depth (cm), (b) bedrock (%), (c) coarse substrate (%), (d) gravel substrate (%), and
(e) fine substrate (%).
Figure 4 (see page 264). Density plots of habitat associated with the occurrence of Little
River Creek Crayfish (gray lines) compared to the available habitat (black lines) in reaches
where we encountered the species The area under each curve accounts for 100% of the
observations and the dashed vertical lines represent the median value associated with used
(gray) and available (black) habitat. Each panel represents a different environmental parameter:
(a) depth (cm), (b) bedrock (%), (c) coarse substrate (%), (d) gravel substrate (%), and
(e) fine substrate (%).
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Figure 3. [Caption on page 262.]
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Figure 4. [Caption on page 262.]
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Figure 5. Density plots of habitat associated
with the occurrence of Ouachita Mountain
Crayfish (gray lines) compared to the
available habitat (black lines) in reaches
where we encountered the species. The
area under each curve accounts for 100%
of the observations and the dashed vertical
lines represent the median value associated
with used (gray) and available (black)
habitat. Each panel represents a different
environmental parameter: (a) depth (cm),
(b) bedrock (%), (c) coarse substrate (%),
(d) gravel substrate (%), and (e) fine substrate
(%).
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surface water (Wood et al. 2010). Additionally, the loss of herbivorous fishes in
the intermittent pools can result in the overgrowth of algae and eventually create
anoxic conditions (Dodds 2002). We measured stream temperatures of intermittent
pools that exceeded 33 °C (maximum = 34.5 °C) and observed fish kills in some of
the pools. Some of the remaining pools appeared to offer suitable habitat, but they
were often occupied by Green Sunfish (Rafinesque) (Lepomis cyanellus). Green
Sunfish predation can alter crayfish habitat selection (Englund and Krupa 2000).
Specifically, Cambarus bartonii (Fabricius) (Common Crayfish) and F. putnami
(Faxon) (= Orconectes putnami) (Phallic Crayfish; Crandall and De Grave 2017)
with total lengths of less than 40 mm (CL < 20 mm) sought refuge in shallow habitats in
the presence of Green Sunfish and other predators (Englund and K rupa 2000). The
combined threats of predation and degrading physicochemical condition may make
the hyporheic zone more suitable than wetted-surface habitat for crayfish during dry
and warm periods.
The differential substrate-use by juveniles and adult crayfish could have been
related to differences in crayfish size and their ability to occupy interstitial spaces.
The adult Mena Crayfish and Little River Creek Crayfish, as well as the Ouachita
Mountain Crayfish (which were primarily adults), occurred more frequently in areas
with coarser substrate; whereas juveniles appeared less selective. Similarly, a
positive relationship between substrate size and the carapace length of the crayfish
seeking refuge has been documented in other field studies (Flinders and Magoulick
2003, Martin et al. 2012). Cambarus hubbsi (Creaser) (Hubbs’ Crayfish) with CL
>15 mm selected habitats with boulder substrates and swift currents that would
prevent fine-sediment deposition, whereas small Hubbs’ Crayfish were negatively
associated with water depth (Flinders and Magoulick 2003). Crayfish can experience
difficulty moving into the hyporheic zone in the absence of coarse substrate
(Dyer et al. 2015, Martin et al. 2012). In laboratory trials, the burrowing depths of
adult F. palmeri longimanus (Faxon) (= Orconectes palmeri longimanus) (Western
Painted Crayfish; Crandall and De Grave 2017), Mena Crayfish, Little River Creek
Crayfish, Kiamichi Crayfish, and Ouachita Mountain Crayfish were significantly
reduced in pebble substrate (32–64 mm) when compared to coarser substrate (Dyer
et al. 2015).
We found that Mena Crayfish and Little River Creek Crayfish had a broader ecological
niche than previously documented; however, Ouachita Mountain Crayfish
were rare in our study. We confirmed the presence of Mena Crayfish and Little River
Creek Crayfish in small to medium-sized streams with rocky substrate (Robison et
al. 2009, Williams 1954), but found that neither species was restricted to permanent
streams and often occupied intermittent streams. Despite the wide range of
Ouachita Mountain Crayfish and considerable sampling effort, we detected only 25
individuals. Bergey et al. (2005) and Jones and Bergey (2007) documented the rarity
of this species, and the International Union for Conservation of Nature lists the
species as data deficient (Crandall 2010). We recognize that our results are based
on only 25 individuals and should be interpreted with caution.
The previous reports of Ouachita Mountain Crayfish as rare within their range
(Bergey et al. 2005, Jones and Bergey 2007) may be an artifact of the sampling
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methods rather than a small population. Occasional detections of Ouachita Mountain
Crayfish using methods targeting lotic-dwelling, tertiary burrowers have
led to the assumption that the species was a lotic dwelling, tertiary burrower;
however, the Ouachita Mountain Crayfish may actually spend the majority of its
time underground. Recent genetic work has placed Ouachita Mountain Crayfish
in Fallicambarus, a genus of primary burrowers, rather than Procambarus, a genus
in which many burrowing strategies are represented (Ainscough et al. 2013).
Although we found Ouachita Mountain Crayfish under large boulders (>500 mm)
within the active stream channel, we also made several observations of Ouachita
Mountain Crayfish by opportunistic excavation of chimney-capped burrows
that were outside of the streambanks and did not fit into our sample design. The
chimney-capped burrows were located in ephemeral forest ditches that flowed into
the stream, but the substrate appeared similar to the soil type on the forest floor.
Further, our failure to detect Ouachita Mountain Crayfish, despite sampling the instream
substrate to a depth of 30 cm and successfully detecting sympatric species
in instream burrows, suggests that the species may rarely inhabit the active channel.
The burrows we found consisted of fine sediment in ephemeral tributaries and
were consistent with other members of the genus. Future studies targeting Ouachita
Mountain Crayfish would benefit from a sampling design that targets primary or
secondary burrowing strategies, rather than stream-dwelling, te rtiary burrowers.
Our growing knowledge of the importance of intermittent habitat to native crayfish
should be helpful to developing effective conservation strategies. Stream drying
is sometimes considered a disturbance (Lake 2000), but under normal conditions,
these crayfish are able to make use of these areas despite surface drying. However,
intensified water demands that accompany climate change could present interesting
challenges for the persistence of aquatic species (Xenopoulos et al. 2005). Crayfish
that burrow will be sensitive to excessive water withdrawals and development that
promotes sedimentation of instream habitat. We encourage researchers to further
examine the role of intermittent stream areas to the persistence of aquatic biota in an
effort to highlight the importance of these areas to overall biodiversity.
Acknowledgments
This research is a contribution of the Oklahoma Cooperative Fish and Wildlife Research
Unit (Cooperators: US Geological Survey, Oklahoma Department of Wildlife Conservation,
Oklahoma State University, and Wildlife Management Institute). Our work was supported
by the Oklahoma Department of Wildlife Conservation (T-60-R). We thank Julia Mueller,
Jarrod Powers, Justin Rowland, and Kortney Kowal for technical assistance. We thank
David Ashley, Bob DiStefano, and an anonymous reviewer for thoughtful comments on an
earlier draft. Any use of trade, firm, or product names is for descriptive purposes only and
does not imply endorsement by the US Government.
Literature Cited
Ainscough, B.J., J.W. Breinholt, H.W. Robison, and K.A. Crandall. 2013. Molecular phylogenetics
of the burrowing crayfish genus Fallicambarus (Decapoda: Cambaridae).
Zoologica Scripta: The Norwegian Academy of Science and Letters 42:306–316.
Southeastern Naturalist
J.J. Dyer and S.K. Brewer
2018 Vol. 17, No. 2
268
Bergey, E.A., S.N. Jones, and D.B. Fenolio. 2005. Surveys and studies of the Oklahoma
Crayfish and the Grotto Salamander. Final Report. University of Oklahoma, Oklahoma
Biological Survey, Norman, OK. 25 pp.
Crandall, K.A. 2010. Fallicambarus tenuis. Available online at http://www.iucnredlist.org/
details/154001/0. Accessed 26 September 2017.
Crandall, K.A., and S. De Grave. 2017. An updated classification of the freshwater crayfishes
(Decapoda: Astacidea) of the world, with a complete species list. Journal of Crustacean
Biology 37:615–653.
Cummins, K.W. 1962. An evaluation of some techniques for the collection and analysis of
benthic samples with special emphasis on lotic waters. American Midland Naturalist
67:477–504.
DiStefano, R.J., C.M. Gale, B.A. Wagner, and R.D. Zweifel. 2003. A sampling method to
assess lotic crayfish communities. Journal of Crustacean Biology 23:678–690.
DiStefano, R.J., D.D. Magoulick, E.M. Imhoff, and E.R. Larson. 2009. Imperiled crayfishes
use the hyporheic zone during seasonal drying of an intermittent stream. Journal of
North American Benthological Society 28:142–152.
Dodds, W.K. 2002. Freshwater Ecology: Concepts and Environment Applications. Academic
Press San Diego, CA. 569 pp.
Dole-Oliver, M. 2011. The hyporheic-refuge hypothesis reconsidered: A review of hydrological
aspects. Marine and Freshwater Research 62:1281–1302.
Dyer, J.J., S.K. Brewer, T.A. Worthington, and E.A. Bergey. 2013. The influence of coarsescale
environmental features on current and predicted future distributions of narrowrange
endemic crayfish populations. Freshwater Biology 58:1071–1 088.
Dyer, J.J., T.A. Worthington, and S.K. Brewer. 2015. Response of crayfish to hyporheic
water availability and excess sedimentation. Hydrobiologia 747: 147–157.
Dyer, J.J., J. Mouser, and S.K. Brewer. 2016. Habitat use and growth of the Western Painted
Crayfish, Orconectes palmeri longimanus (Faxon, 1898) (Decapoda: Cambaridae). Journal
of Crustacean Biology 36:172–79.
Englund, G., and J.J. Krupa. 2000. Habitat use by crayfish in stream pools: Influence of
predators, depth, and body size. Freshwater Biology 43:75–83.
Flinders, C.A., and D.D. Magoulick. 2003. Effects of stream permanence on crayfish community
structure. The American Midland Naturalist 149:134–147.
Jones, D.R. 2016. A new crayfish of the genus Cambarus (Decapoda: Cambaridae) from the
Flint River drainage in northern Alabama and south-central Tennessee, USA. Zootaxa
4103:43–53.
Jones, S.N., and E.A. Bergey. 2007. Habitat segregation in stream crayfishes: Implications
for conservation. Journal of the North American Benthological Society 26:134–144.
Lake, P.S. 2000. Disturbance, patchiness, and diversity in streams. Journal of the North
American Benthological Society 19:573–592.
Loughman, Z.J., and J.W.J. Fetzner. 2015. Astacology and crayfish conservation in the
southeastern United States: Past, present, and future. Freshwat er Crayfish 21:1–5.
Martin, S.D., B.A. Harris, J.R. Collums, and R.M. Bonett. 2012. Life between predators and
a small space: Substrate selection of an interstitial space-dwelling stream salamander.
Journal of Zoology 287:205–214.
Robison, H.W., and C.T. McAllister. 2008. Additional distribution records of the Ouachita
Mountain Crayfish, Procambarus tenuis (Decapoda: Cambaridae), in Arkansas and
Oklahoma with notes on ecology and natural history. Proceedings of the Oklahoma
Academy of Science 88:27–34.
Southeastern Naturalist
269
J.J. Dyer and S.K. Brewer
2018 Vol. 17, No. 2
Robison, H.W., B.G. Crump, C.T. McAllister, C. Brummett, and E.A. Bergey. 2009. Distribution,
life-history aspects, and conservation status of the Mena Crayfish, Orconectes
(Procericambarus) menae (Decapoda: Cambaridae). Proceedings of the Oklahoma
Academy of Science 89:47–56.
Schuster, G.A., C.A. Taylor, and S.B. Adams. 2015. Procambarus (Girardiella) holifieldi,
a new species of crayfish (Decapoda: Cambaridae) from Alabama with a revision of the
Hagenianus Group in the subgenus Girardiella. Zootaxa 4021:1–32.
Simon, T.P. 2011. Conservation status of North American freshwater crayfish (Decapoda:
Cambaridae) from the southern United States. Proceedings of the Indiana Academy of
Science 120:71–95.
Strahler, A.N. 1957. Quantitative analysis of watershed geomorphology. Transactions of the
American Geophysical Union 38:913–920.
Strauss, R.E. 1982 Influence of replicated subsamples and subsam ple heterogeneity on the
linear index of food selection. Transactions of the North American Fisheries Society
111:517–522.
Taylor, C.A., G.A. Schuster, J.E. Cooper, R.J. DiStefano, A.G. Eversole, P. Hamr, H.H.
Hobbs III, H.W. Robison, C.E. Skelton, and R.F. Thomas. 2007. A reassessment of the
conservation status of crayfishes of the United States and Canada after 10+ years of
increased awareness. Fisheries 32:372–389.
Thoma, R.F., and J.W.J. Fetzner. 2015. Cambarus (Jugicambarus) magerae, a new species
of crayfish (Decapoda: Cambaridae) from Virginia. Proceedings of the Biological Society
of Washington.128:11–21.
Williams, A.B. 1954. Species distribution of the crayfish of the Ozark plateaus and Ouachita
provinces. University of Kansas Science Bulletin 36:803–918.
Wood, P.J., A.J. Boulton, S. Little, and R. Stubbinton. 2010. Is the hyporheic zone a refugium
for aquatic macroinvertebrates during severe low-flow conditions? Fundamental
and Applied Limnology/ Archiv fur Hydrobiologie 176:377–390.
Woods, A.J., J.M. Omernik, D.R. Butler, J.G. Ford, J.E. Henley, B.W. Hoagland, D.S Arndt,
and B.C. Morgan. 2005. Ecoregions of Oklahoma. US Geological Survey, Reston, VA.
Map scale = 1:1,000,000. Available online at https://archive.epa.gov/wed/ecoregions/
web/html/ok_eco.html. Accessed August 2017.
Xenopoulos, M.A., D.M. Lodge, J. Alcamo, M. Marker, K. Schulze, and D.P. Van Vuurens.
2005. Scenarios of freshwater-fish extinctions from climate change and water withdrawal.
Global Change Biology 11:1557–1564.