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The Journal of Wildlife Management 84(3):478–491; 2020; DOI: 10.1002/jwmg.21821
Research Article
Reptiles Under the Conservation Umbrella
of the Greater Sage‐Grouse
DAVID S. PILLIOD ,
1
U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, 970 Lusk Street, Boise, ID 83706, USA
MICHELLE I. JEFFRIES ,U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, 970 Lusk Street, Boise, ID 83706, USA
ROBERT S. ARKLE ,U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, 970 Lusk Street, Boise, ID 83706, USA
DEANNA H. OLSON ,U.S. Department of Agriculture Forest Service, Pacific Northwest Research Station, Forestry Sciences Laboratory,
3200 SW Jefferson Way, Corvallis, OR 97331, USA
ABSTRACT In conservation paradigms, management actions for umbrella species also benefitco‐occurring
species because of overlapping ranges and similar habitat associations. The greater sage‐grouse (Centrocercus
urophasianus) is an umbrella species because it occurs across vast sagebrush ecosystems of western North
America and is the recipient of extensive habitat conservation and restoration efforts that might benefit
sympatric species. Biologists' understanding of how non‐target species might benefitfromsage‐grouse con-
servation is, however, limited. Reptiles, in particular, are of interest in this regard because of their relatively
high diversity in shrublands and grasslands where sage‐grouse are found. Using spatial overlap of species
distributions, land cover similarity statistics, and a literature review, we quantified which reptile species may
benefit from the protection of intact sage‐grouse habitat and which may be affected by recent (since about
1990) habitat restoration actions targeting sage‐grouse. Of 190 reptile species in the United States
and Canadian provinces where greater sage‐grouse occur, 70 (37%) occur within the range of the bird.
Of these 70 species, about a third (11 snake and 11 lizard species) have >10% of their distribution area
within the sage‐grouse range. Land cover similarity indices revealed that 14 of the 22 species (8 snake and
6 lizard species) had relatively similar land cover associations to those of sage‐grouse, suggesting greater
potential to be protected under the sage‐grouse conservation umbrella and greater potential to be affected,
either positively or negatively, by habitat management actions intended for sage‐grouse. Conversely, the
remaining 8 species are less likely to be protected because of less overlap with sage‐grouse habitat and thus
uncertain effects of sage‐grouse habitat management actions. Our analyses of treatment databases indicated
that from 1990 to 2014 there were at least 6,400 treatments implemented on public land that covered
approximately 4 million ha within the range of the sage‐grouse and, of that, >1.5 million ha were intended to
at least partially benefitsage‐grouse. Whereas our results suggest that conservation of intact sagebrush
vegetation communities could benefit≥14 reptiles, a greater number than previously estimated, additional
research on each species' response to habitat restoration actions is needed to assess broader claims of multi‐
taxa benefits when it comes to manipulative sage‐grouse habitat management. Published 2020. This article
is a U.S. Government work and is in the public domain in the USA.
KEY WORDS Centrocercus urophasianus, land treatment, rangelands, sagebrush, Squamata, umbrella species.
Single‐species management influences many wildlife con-
servation efforts in the United States (Simberloff1998, Evans
et al. 2016, Johnson et al. 2017). In an era of ecosystem‐and
landscape‐level resource management, however, managers
commonly assume that species‐specific habitat protection and
management actions also indirectly benefit other wildlife
species. This umbrella species concept (Wilcox 1984) infers
that many co‐occurring species will be protected by con-
serving the habitat of a single species (Caro and O'Doherty
1999, Roberge and Angelstam 2004). Applying this con-
servation concept in practice requires that ≥3 criteria are met.
First, protecting intact habitat for the umbrella species should
benefittheco‐occurring species. Second, the range of the
umbrella species should be large compared to the range of
co‐occurring species (Wilcox 1984). Third, restoration or
management actions targeting the umbrella species should
also benefit, or at least not negatively affect, co‐occurring
species (Ozaki et al. 2006). Although the umbrella species
concept has been criticized as overly simplistic and optimistic
(Andelman and Fagan 2000, Cushman et al. 2010, Runge
et al. 2019), researchers suggest that species richness of
co‐occurring (i.e., potential beneficiary) species can be higher
in locations where umbrella species are present (Branton and
Richardson 2011).
The greater sage‐grouse (Centrocercus urophasianus)isanim-
portant umbrella species in sagebrush vegetation communities
Received: 23 January 2019; Accepted: 26 November 2019
1
E‐mail: dpilliod@usgs.gov
478 The Journal of Wildlife Management •84(3)
of western North America, ostensibly benefiting a wide range
of taxa (Rowland et al. 2006, Hanser and Knick 2011). This
ground‐nesting bird occurs in parts of 11 states in the United
States and 2 Canadian provinces (Knick and Connelly 2011).
Many individuals migrate seasonally across large (4–615 km
2
)
landscapes to access requisite nesting, foraging, and sheltering
habitats (Connelly et al. 2011). The overlap of the sage‐grouse
distribution with private and government‐administered grazing
lands, agricultural lands, and lands rich in mineral and energy
resources has created conservation conflict and opportunity.
Partnerships from local to national levels have formed over
the last 2 decades to stem the decline of sage‐grouse pop-
ulations by identifying and protecting the best remaining
habitat, restoring degraded areas, and rehabilitating habitat al-
tered by wildfire, oil and gas development, and other dis-
turbances (Belton and Jackson‐Smith 2010, Murphy et al.
2013, Duvall et al. 2017).
Since the first petition to federally list the greater sage‐
grouse under the United States Endangered Species Act
(ESA) in 2002, several range‐wide habitat conservation
strategies have been developed and their implementation is
ongoing (U.S. Fish and Wildlife Service [USFWS] 2013).
For example, in the last 2 decades, vegetation on >2 million
ha of private land has been actively managed under the
guidance of the Greater Sage‐Grouse Comprehensive
Conservation Strategy (Stiver et al. 2006) and Sage‐Grouse
Initiative (U.S. Department of Agriculture 2015). On
public lands, the United States Department of Interior
Bureau of Land Management (BLM) and United States
Department of Agriculture Forest Service (USFS)
Resource Management Plans have recommended manage-
ment actions across millions of hectares, including the re-
moval of single leaf‐pinyon pine (Pinus monophyla),
Colorado pinyon (P. edulis), western juniper (Juniperus oc-
cidentalis), and Utah juniper ( J. osteosperma) woodlands,
control of cheatgrass (Bromus tectorum) and other exotic
annual grasses, and restoration of big sagebrush (Artemisia
tridentata) following wildfires. Given the recent emphasis
being placed on protecting intact sage‐grouse habitat and
the extent of management actions where sagebrush has
been lost or degraded (Arkle et al. 2014), there is growing
interest among stakeholders in assessing potential benefits
or consequences of these expansive conservation efforts on
co‐occurring species. The Sagebrush Science Initiative
sponsored by the Western Association of Fish and Wildlife
Agencies and the USFWS is a good example (https://www.
wafwa.org/initiatives/sagebrush_ecosystem_initiative/, ac-
cessed 18 Sep 2019).
There is limited information concerning potential benefits
to different wildlife species under the sage‐grouse con-
servation umbrella, which is worrisome given that a
one‐size‐fit‐all approach rarely works in wildlife habitat
management (Zipkin et al. 2010). A few studies have ad-
dressed this issue, mainly focusing on other birds and
mammals (McAdoo et al. 2004, Beck et al. 2012, Copeland
et al. 2014, Donnelly et al. 2017, Carlisle et al. 2018a).
Information on reptiles is particularly scarce, especially re-
garding the potential responses of reptile taxa to restoration
actions. A few recent studies, however, have included rep-
tiles in their assessments of the likelihood of protecting
wildlife species under the sage‐grouse umbrella (Rowland
et al. 2006, Carlisle et al. 2018b, Runge et al. 2019). These
assessments focused solely on species considered to be
sagebrush obligates or associates. Collectively, these studies
examined only 24 reptile species, including 9 species in the
Great Basin (Rowland et al. 2006), 13 species in Wyoming,
USA (Carlisle et al. 2018b), and 8 species across the range
of the greater sage‐grouse (Runge et al. 2019). But only
5 lizard species were common between Rowland et al.
(2006) and Runge et al. (2019) and only 1 snake species was
common between Carlisle et al. (2018b) and Runge
et al. (2019).
Because of the lack of consistency among these assessments
and the likely need for information on reptile species beyond
those considered sagebrush obligate or sagebrush associate,
we sought to conduct a more comprehensive and quantitative
assessment of which western North American reptile species
may benefit from sage‐grouse conservation efforts, namely
conservation of intact sage‐grouse habitat and restoration of
degraded areas. Our specific objectives were to determine
which reptile species are likely to benefit most from pro-
tecting intact sage‐grouse habitat, how likely are restoration
treatments targeting sage‐grouse to overlap with each reptile
species, how likely are these management actions to alter a
substantial portion of each species' range, what is the preva-
lence of different sage‐grouse treatment actions between 1990
and 2014, and how might different reptile species be affected
by these various treatments according to past studies and
relative to their conservation status.
STUDY AREA
This study spanned the range of the greater sage‐grouse
as estimated in 2014 (Lindstrom 2014), which included
70 million ha across western North America in
California, Colorado, Idaho, Montana, Nevada, North
Dakota, Oregon, South Dakota, Utah, Washington, and
Wyoming, USA, and in Alberta and Saskatchewan,
Canada (Fig. 1). The vast range of the sage‐grouse en-
compassed many environmental gradients and land cover
types (West and Young 2000, Shinneman 2019), but the
birds were generally associated with sagebrush‐steppe
and sagebrush semi‐desert plant assemblages (Crawford
et al. 2004). The sage‐grouse range had a mean elevation of
1,602 m (range =129–4,096 m), mean annual precipitation
of 334 mm (range =122–1,311 mm), and mean annual
temperature of 6.9°C (range =−3.1–14.3°C; 30‐year
average 1981–2010; Parameter‐elevation Relationships on
Independent Slopes Model [PRISM] Climate Group,
Oregon State University, http://prism.oregonstate.edu,
accessed 17 Sep 2019).
METHODS
We first identified all reptile species that occur in the
11 states and 2 provinces in the greater sage‐grouse range by
examining reptile range maps that follow standard
taxonomy and nomenclature (Crother 2017). Range maps
Pilliod et al. •Sage‐Grouse as an Umbrella Species for Reptiles 479
are defined as the extent of a species' geographic limits
(U.S. Geological Survey [USGS] 2018). We then used a
geographic information system (GIS; Esri ArcGIS 10.6,
Redlands, CA, USA) to determine the overlap between the
range of each reptile species (USGS 2018, International
Union for the Conservation of Nature [IUCN] 2017) and
the 2014 range of the greater sage‐grouse (Lindstrom 2014)
buffered by 35 km. The 35‐km buffer distance represents the
maximum distance the habitat management areas polygon
(BLM 2017) extends beyond the sage‐grouse range polygon
(Lindstrom 2014). We also used the species' range maps to
depict reptile species richness across the range of the greater
sage‐grouse (Fig. 1). Gap analysis project range maps were
unavailable for 11 of the 190 reptile species within the study
area (USGS 2018), so we used other sources (Leache 2009,
Krysko et al. 2017, Nafis 2018) for the 11 species: forest
sharp‐tailed snake (Contia longicauda), panamint rattlesnake
(Crotalus stephensi), California kingsnake (Lampropeltis
californiae), speckled kingsnake (Lampropeltis holbrooki),
Madrean mountain kingsnake (Lampropeltis knoblochi),
desert kingsnake (Lampropeltis splendida), rosy boa
(Lichanura orcutti), prairie lizard (Sceloporus consobrinus),
southwestern fence lizard (Sceloporus cowlesi), Sonoran
lyresnake (Trimorphodon lambda), and California lyresnake
(Trimorphodon lyrophanes). We did not include 8 of these
species in analyses because they did not overlap with the
range of the sage‐grouse: forest sharp‐tailed snake, speckled
kingsnake, Madrean mountain kingsnake, desert kingsnake,
rosy boa, southwestern fence lizard, Sonoran lyresnake, and
California lyresnake. We did not include 3 of these species
because GAP predicted habitat maps were unavailable:
panamint rattlesnake, California kingsnake, and prairie
lizard.
To determine which reptile species might benefit most
from protection of intact sage‐grouse habitat, we refined our
list of relevant reptile species by assessing the similarity of
each species' habitat to habitats occupied by sage‐grouse.
Using reclassified (Table S1, available online in Supporting
Information) land cover data derived from LANDFIRE
(2014), we calculated the proportion of each land cover type
across the predicted habitat of each species (USGS 2018).
The GAP predicted habitat maps are described as:
“Mapped areas represent places where the environment
is suitable for the species to occur (i.e., suitable to sup-
port one or more life history requirements for breeding,
resting, or foraging), while areas not included in the map
are those predicted to be unsuitable for the species.
These habitat maps are created by applying a deductive
habitat model to remotely‐sensed data layers within a
species' range. The deductive habitat models are built by
compiling information on species' habitat associations
into a relational database. Information is compiled from
the best available characterizations of species' habitat, which
includedspeciesaccountsinbooksanddatabases,as
well as primary peer‐reviewed literature”(https://
www.usgs.gov/core‐science‐systems/science‐analytics‐
and‐synthesis/gap/science/species‐data‐overview, ac-
cessed 18 Sep 2019).
We used these predicted habitat maps as a proxy for species
distributions, which provided a finer resolution and ecologi-
cally more realistic potential area of occupancy compared
with range maps. The predicted habitat maps for each reptile
was based on information compiled and modeled from 2008
to 2016 in the western United States, which restricted sub-
sequent analyses to the United States (USGS 2018).
For each reptile species, we calculated a Bray‐Curtis dis-
similarity (or distance) value (Ricotta and Podani 2017) by
comparing the land cover proportions of the sage‐grouse to
those of the reptile. We focused on reptiles with dissimilarity
values <0.5 (group I species), whereas we classified reptiles
with values >0.5 (group II species) as relatively dissimilar to
sage‐grouse with regards to land cover (i.e., a component of
habitat) within their distribution. We selected this cutoff
because it was a natural breakpoint in the data and because it
conveniently divided the reptiles into 2 similarly sized groups.
We plotted each species' land cover dissimilarity value and
distribution overlap with sage‐grouse to rank their potential
as a beneficiary species based on both criteria.
To identify which species are potentially influenced by
sage‐grouse habitat management actions, we calculated the
size of each group I and group II reptile species' distribution
and identified those with small distributions and a high
proportion of distribution overlap with the range of the
sage‐grouse. We assumed that species with smaller dis-
tributions would be more sensitive to management actions
because of the potential to affect (either positively or
Figure 1. Reptile species richness created from compiling individual range
polygons in western North America, 2008–2016. Large polygons depict
the range of the greater sage‐grouse in 2014 and polygons nested within
these show priority habitat management areas designated for greater sage‐
grouse. Numbers indicate reptile species richness estimated for particular
locations, as examples.
480 The Journal of Wildlife Management •84(3)
negatively) a greater proportion of the species' distribution
and species with small distributions would tend to be more
vulnerable to extinction (Pimm et al. 2014). We conducted
a similar analysis to assess which species might be dis-
proportionately affected by restoration or management ac-
tions because they have small distributions and a high
proportion of their distribution within the sage‐grouse
range. We performed Bray‐Curtis dissimilarity analyses in R
using the vegan package (R Core Team 2017, Oksanen
et al. 2018).
We created an additional metric to help distinguish the
potential sensitivity of reptile species to sage‐grouse habitat
management by assuming that locations with greater levels
of management actions targeting sage‐grouse habitat may
have increased effects on reptiles. Consequently, we calcu-
lated the proportion of the sage‐grouse's range that is oc-
cupied by each reptile species (i.e., overlapping area of a
given species divided by the range of the sage‐grouse), and
the proportion of each reptiles species' distribution falling
within areas more likely to be protected or heavily managed
for sage‐grouse (Fig. 2). To represent these areas, we
used priority habitat management areas (PHMAs; BLM
2017), which are areas designated in approved Resource
Management Plans for each state (Landscape Data
Approach Portal: https://landscape.blm.gov/geoportal/
catalog, accessed 14 Jun 2019) and defined as the most
valuable habitat for the greater sage‐grouse. A relatively large
overlap with these areas indicates the possibility of man-
agement decisions affecting the overlapping reptile species.
To better understand what habitat management actions
are implemented in the range of the greater sage‐grouse, we
queried the Land Treatment Digital Library (LTDL;
Pilliod and Welty 2013). The LTDL is a legacy dataset that
houses historical BLM land treatments (Pilliod et al. 2017).
The LTDL was recently updated to include all available
land treatments occurring prior to 2015 within the range of
the sage‐grouse to provide information to the USFWS
for the sage‐grouse ESA listing decision in 2015. We ran
2 LTDL queries to extract the number of treatments that
occurred between 1990 and 2014 in the range of sage‐
grouse, and within the PHMAs. Then we identified the
number of treatments that were implemented to benefit
sage‐grouse by querying the database treatment‐justification
fields for the words sage and grouse. We also generated a
summary report from the Conservation Efforts Database
(USFWS 2014; conservationefforts.org, accessed 1 Oct
2018) to identify treatments specifically planned to benefit
the greater sage‐grouse on private and public lands (Heller
et al. 2017). To provide the most reliable information, we
chose to report information from these databases only for
land treatments with implementation status that was con-
firmed in the field (Pilliod et al. 2017). Thus, combining
information from both sources provides a sample (i.e., not a
census) of all management actions, which represent min-
imum values for land area treated. Nonetheless, these land
treatment summaries provide the types of treatments, rela-
tive amounts, and minimum areas treated in the range of the
greater sage‐grouse from 1990 to 2014.
Finally, we conducted a literature search to assess how
different reptile species might be affected by these various
treatments. To search the literature, we used the words or
terms sagebrush and reptile or snake or lizard or turtle, plus
treatment, restoration, habitat management, seeding,
Figure 2. A) Distribution of an example reptile species (black); B) range
of the greater sage‐grouse in 2014 (gray), and the area of overlap with the
example reptile species (black); and C) overlap (black) between the
distribution of an example reptile species and the priority habitat
management areas for greater‐sage grouse (light gray). The example
reptile used in these figures is the pygmy short‐horned lizard in the western
United States using modeled data, 2008–2013.
Pilliod et al. •Sage‐Grouse as an Umbrella Species for Reptiles 481
grazing, conifer removal, mastication, or prescribed fire in
Google Scholar (Google, Mountain View, CA, USA) on
3 June 2019. We reviewed the abstracts and text of each
selection for inclusion of reptiles and relevance to the types
of treatments that are conducted for sage‐grouse. We then
presented informative findings from past studies in a table
for group I reptile species along with their observed rela-
tionships to several types of restoration or management
actions (i.e., seeding, grazing, conifer removal). We also
generated a table of the national and state‐level conservation
status of each group I reptile species to provide context for
those species that are common and secure compared to
those that are declining or at risk of extinction.
RESULTS
We mapped 190 reptile species in western North America.
Species richness was generally highest in the southwest
portion of the study area and lowest in the northeast
(Fig. 1). Although the northeastern areas had lower species
richness, richness was still surprisingly high, with some
PHMAs in the northeast having as many as 13 reptile
species (Fig. 1), mainly snakes. In contrast, the south-
western portion of the sage‐grouse range had up to
35 species (Fig. 1), comprised equally of snakes and lizards
(Order Squamata; Fig. S1, available online in Supporting
Information). Nearly all of the sage‐grouse range had
≥5 reptile species (¯
x
±SD richness across all pixels =
12.8 ±5.6) and no areas were expected to be devoid of
reptiles. The PHMAs had the same range of richness values
(2–38 species) and a similar mean richness (12.2 ±5.3
species) as the sage‐grouse range.
Reptile Species That Might Benefit Under the
Sage‐Grouse Conservation Umbrella
Of the 190 reptile species, 70 (37%) overlapped with the
range of the greater sage‐grouse and 22 of those species
overlapped substantially (i.e., they had >10% of their dis-
tribution within the sage‐grouse range; Table 1). These
included 11 snakes and 11 lizards but no turtles. Fourteen of
these 22 (64%) substantially overlapping species shared
similar land covers with sage‐grouse (i.e., group I; Fig. 3).
The remaining 8 substantially overlapping species occupied
land covers that were less similar to sage‐grouse habitat (i.e.,
group II; Fig. 3).
Using multiple criteria, such as species distribution size,
distributional overlap with sage‐grouse, and land cover
similarity to sage‐grouse, we ranked the species likely to
benefit from sage‐grouse conservation (Table 1; details
provided in Table S2, available online in Supporting
Information). Of the 14 group I species, the pygmy short‐
horned lizard (Phrynosoma douglasii) stood out from the rest
with the largest percent of its distribution within the range
of the greater sage‐grouse (62.5%; Fig. 2B) and the highest
similarity of land cover to sage‐grouse (Table 1; Fig. 3). The
remaining 13 group I species also may benefit from the
sage‐grouse conservation umbrella, but different factors in-
fluenced their rank and some tended to cluster together.
The desert horned lizard (Phrynosoma platyrhinos), long‐
nosed leopard lizard (Gambelia wislizenii), tiger whiptail
(Aspidoscelis tigris), western skink (Plestiodon skiltonianus),
plains gartersnake (Thamnophis radix), and Arizona moun-
tain kingsnake (Lampropeltis pyromelana) are good examples
(Fig. 3). Some group II species have more distributional
Table 1. The 22 reptile species that overlap with the 2014 range of the greater sage‐grouse by >10% of their distribution in the western United States using
modeled distribution data, 2008–2016. We determined species ranks by the value of the composite distribution overlap and habitat similarity score (dividing
the distribution overlap by the dissimilarity score). We calculated the proportion of distribution overlap as overlapping area between the reptile and sage‐
grouse divided by area of reptile distribution. We calculated land cover dissimilarity using the Bray‐Curtis distance, where a value closer to zero indicates
similarity, and a value closer to 1 indicates dissimilarity. An asterisk indicates the 14 species that are most likely to benefit under the conservation umbrella for
sage‐grouse on the basis of both proportion of their distribution overlapping with sage‐grouse and land cover similarity with sage‐grouse.
Common name
Proportional overlap of reptile distribution within
the range of greater sage‐grouse
Land cover
dissimilarity score Rank
Pygmy short‐horned lizard* 0.625 0.199 1
Common sagebrush lizard* 0.380 0.296 2
Greater short‐horned lizard* 0.326 0.334 3
Northern rubber boa* 0.344 0.396 4
Striped whipsnake* 0.273 0.341 5
Western fence lizard* 0.315 0.407 6
Desert nightsnake* 0.314 0.421 7
Western rattlesnake* 0.269 0.406 8
Desert horned lizard 0.324 0.522 9
Terrestrial gartersnake* 0.266 0.432 10
Common side‐blotched lizard* 0.198 0.453 11
Gophersnake* 0.153 0.357 12
Great Basin collared lizard 0.232 0.564 13
Long‐nosed leopard lizard 0.214 0.529 14
Prairie rattlesnake* 0.168 0.430 15
Plains hog‐nosed snake 0.193 0.524 16
North American racer* 0.100 0.320 17
Western skink 0.147 0.563 18
Plateau fence lizard* 0.107 0.427 19
Tiger whiptail 0.146 0.586 20
Plains gartersnake 0.101 0.600 21
Arizona mountain kingsnake 0.105 0.706 22
482 The Journal of Wildlife Management •84(3)
overlap with sage‐grouse than group I species and some of
these had land cover similarity values close to our 0.5 Bray‐
Curtis threshold; these species, in particular, may also
benefit from sage‐grouse conservation. The milksnake
(Lampropeltis triangulum) and smooth green snake
(Opheodrys vernalis) fell just below the 10% threshold of
distribution overlap but they share similar land cover as
sage‐grouse and thus could benefit in the few locations
where they do overlap with sage‐grouse (i.e., group III
species; Fig. 3). Group IV species would be least likely to
benefit by the sage‐grouse conservation umbrella because
they have the least overlap of ranges and least land cover
similarity.
Reptile Species That Are Likely to Overlap with
Management Actions Targeting Sage‐Grouse
After evaluating the extent to which reptile species share
space and land cover with sage‐grouse, we next evaluated
which species are more likely to be affected by restoration
actions across the range of the sage‐grouse (Fig. 4A). The
North American racer (Coluber constrictor) and gophersnake
(Pituophis catenifer) had large distributions and most
(>65%) of the range of the sage‐grouse was predicted to be
occupied by these species (Fig. 4A). Hence, any manage-
ment actions within the range of the sage‐grouse might
affect these 2 colubrid snakes, but their distributions are so
large that the species are not particularly vulnerable range‐
wide, although local effects may still occur. In contrast, the
pygmy short‐horned lizard and plateau fence lizard
(Sceloporus tristichus) were group I species with relatively
small distributions, but only a small proportion of the range
of the sage‐grouse was predicted to be occupied by these
species (Fig. 4A). Hence, across the range of the sage‐
grouse, management actions are less likely to affect these
species because they occur only in a small portion of the
sage‐grouse range. Following this logic, the remainder (and
majority) of group I species could be vulnerable to man-
agement actions because of the limited size of their dis-
tribution and how much of the sage‐grouse's range is likely
to be occupied by them (Fig. 4A). Notable species in this
potentially affected group include common sagebrush lizard,
greater short‐horned lizard (Phrynosoma hernandesi), terres-
trial gartersnake (Thamnophis elegans), and northern rubber
boa (Charina bottae).
The common sagebrush lizard stood out within this group
of species because it had a relatively small distribution and
around 75% of the range of the sage‐grouse was predicted to
be occupied by this species. In other words, many habitat
management decisions for sage‐grouse have the potential to
affect this species. On the other hand, much (62%) of the
common sagebrush lizard distribution lies outside of the
sage‐grouse range and thus falls outside of management
areas (Fig. 4B).
Group II species tend to have relatively small proportional
overlap with sage‐grouse and small distribution sizes
(Fig. 4A). They are partly constrained to have less overlap
Figure 3. Reptile species that overlap with greater sage‐grouse in the western United States and their land cover dissimilarity. We calculated the
proportional overlap (y‐axis) as the area of overlap (between each reptile distribution, 2008–2016, and the 2014 range of sage‐grouse) divided by the
distribution area of the reptile. The land cover dissimilarity (x‐axis) values are Bray‐Curtis distances between land cover proportions of each reptile and sage‐
grouse. A distance value closer to zero indicates greater similarity, whereas a value close to 1 indicates dissimilar land cover preferences. The vertical dashed
line indicates the similarity threshold and the horizontal dashed line indicates the overlap threshold. Circles represent snakes, squares for lizards, and
triangles for turtles. Species abbreviations are COSL =common sagebrush lizard, CSBL =common side‐blotched lizard, DENI =desert nightsnake,
DHLI =desert horned lizard, GBCL =Great Basin collared lizard, GOPH =gophersnake, GSHL =greater short‐horned lizard, LNLL =long‐nosed
leopard lizard, MILK =milksnake, NARA =North American racer, NRBO =northern rubber boa, OTLI =ornate tree lizard, PALI =panamint alligator
lizard, PFLI =plateau fence lizard, PHNS =plains hog‐nosed snake, PLGA =plains gartersnake, PRRA =prairie rattlesnake, PSHL =pygmy short‐horned
lizard, SMGR =smooth green snake, SMKI =Arizona mountain kingsnake, STWH =striped whipsnake, TEGA =terrestrial gartersnake, TIWH =tiger
whiptail, WERA =western rattlesnake, WESK =western skink, WFLI =western fence lizard, and WPNS =western patch‐nosed snake.
Pilliod et al. •Sage‐Grouse as an Umbrella Species for Reptiles 483
with sage‐grouse by virtue of their use of relatively dissimilar
land covers to those used by the bird.
Reptile Species That Could Be Disproportionately
Affected by Management Actions Targeting
Sage‐Grouse
When we plotted reptile distribution size versus proportional
distribution overlap, this time relative to the distribution of
each reptile (Fig. 4B) as opposed to relative to the sage‐
grouse range, the pygmy short‐horned lizard stood out be-
cause it has the smallest distribution of any group I reptile
examined and 62.5% of its range is contained within the
sage‐grouse range. Therefore, where the lizard occurs, man-
agement actions targeting sage‐grouse habitat could have a
disproportionately large effect on this lizard because it has
such a small distribution and the majority of it lies within the
Figure 4. The relationship between distribution size of each reptile and overlap with the 2014 range of sage‐grouse for the reptile species that share >10%
distribution overlap with sage‐grouse in the western United States. Reptile distribution used modeled data, 2008–2016. Group I species are represented in
black and group II in gray. Panel A shows the overlap relative to the sage‐grouse. We calculated the x‐axis by the overlap (between each reptile and the range
of sage‐grouse) area divided by the area of the range of sage‐grouse. Panel B shows the overlap relative to the reptile. The x‐axis is calculated by the overlap
(between each reptile and the range of the sage‐grouse) area divided by the total area of the reptile distribution. The y‐axis for both panels shows
the distribution size for each reptile (×1,000 km
2
). The species included in reptile group I are those that overlap with sage‐grouse (>10% of the reptile
distribution overlaps) and have similar land cover proportions to sage‐grouse (Bray‐Curtis distance <0.5). The species included in reptile group II are those
that overlap with sage‐grouse (>10% of the reptile distribution overlaps) and have dissimilar land cover proportions to sage‐grouse (Bray‐Curtis distance
>0.5). Snakes are represented as circles and lizards as squares. Species abbreviations are COSL =common sagebrush lizard, CSBL =common side‐blotched
lizard, DENI =desert nightsnake, DHLI =desert horned lizard, GBCL =Great Basin collared lizard, GOPH =gophersnake, GSHL =greater short‐
horned lizard, LNLL =long‐nosed leopard lizard, NARA =North American racer, NRBO =northern rubber boa, PFLI =plateau fence lizard,
PHNS =plains hog‐nosed snake, PLGA =plains gartersnake, PRRA =prairie rattlesnake, PSHL =pygmy short‐horned lizard, SMKI =Arizona mountain
kingsnake, STWH =striped whipsnake, TEGA =terrestrial gartersnake, TIWH =tiger whiptail, WERA =western rattlesnake, WESK =western skink,
WFLI =western fence lizard.
484 The Journal of Wildlife Management •84(3)
range of the sage‐grouse. Eight other group I species clus-
tered together (Fig. 4B) with relatively small distribution
sizes and 25–40% of their distribution area overlapping with
the sage‐grouse range: common sagebrush lizard, greater
short‐horned lizard, western fence lizard (Sceloporus
occidentalis), northern rubber boa, striped whipsnake (Coluber
taeniatus), desert nightsnake (Hypsiglena chlorophaea), western
rattlesnake (Crotalus oreganus), and terrestrial gartersnake.
Common side‐blotched lizard (Uta stansburiana) and prairie
rattlesnake (Crotalus viridis) tended to align more closely with
some group II species (Fig. 4B), including long‐nosed
leopard lizard, Great Basin collared lizard (Crotaphytus
bicinctores), and plains hog‐nosed snake (Heterodon nasicus).
Because habitat management is unlikely to be uniformly
distributed across the range of the sage‐grouse, we then
focused on potential effects (both positive and negative) to
reptiles within PHMAs; areas most likely to be managed
specifically for sage‐grouse habitat and population persis-
tence. When we assessed reptiles within PHMAs, species
clustered similarly to how they clustered across the entire
range of the sage‐grouse. This indicates that reptile species'
area of overlap with PHMAs and the entire sage‐grouse
range are correlated, and that species' relationships with
PHMAs are representative of those across the sage‐grouse's
range (Fig. S2, available online in Supporting Information).
Prevalence of Management Actions Targeting
Sage‐Grouse
From 1990 to 2014, ≥6,400 land treatments covering about
4 million ha have occurred on BLM land within the range
of the greater sage‐grouse (Table 2). Approximately a third
of these treatments were implemented with sage‐grouse
cited as a specific justification for the management action.
Nearly 40% of these land treatments occurred within
PHMAs, despite PHMAs only comprising about a third of
the sage‐grouse range. Within PHMAs, 44% of treatments
implemented from 1990 to 2014 were undertaken to benefit
sage‐grouse specifically. Overall, vegetation seeding
accounted for 41% of the treatments and 65% of the area
treated (Table 2). Most of these seedings were post‐fire
treatments. Improving sage‐grouse habitat is usually a
secondary goal of these post‐fire seedings with the main goal
to prevent burned areas from further degrading (e.g., being
dominated by non‐native, annual grasses and forbs).
In addition to LTDL data, 6,022 records in the
Conservation Efforts Database (CED) described sage‐
grouse habitat conservation actions occurring on approx-
imately 1.25 million ha of private and public lands from
2000 to 2014 (some of these treatments overlap with those
in the LTDL database). Consistent with treatments on
BLM lands, about 40% of the conservation efforts reported
in the CED occurred within the PHMAs. The 2 most
frequent conservation efforts documented in the CED were
vegetation management and habitat enhancement (2,639
actions, 43.8% of all records) and conifer removal (1,032
actions, 17% of all records). In contrast to the post‐fire
seeding treatments described above, the primary goal of
these types of treatments often is to improve existing sage‐
grouse habitat explicitly. It is important to consider that
these values are minimums because we were confident re-
porting only treatments verified as fully implemented or
completed in the LTDL and CED from 1990 to 2014 or
from 2000 to 2014, respectively. Also, these databases are
not a census of all treatments implemented and additional
management actions have occurred since. For example, in
Utah, 233,500 ha of public and private land have been
treated or are planned to be treated in sage‐grouse man-
agement areas between 2008 and 2020 (www.wri.utah.gov,
accessed 18 Sep 2019). Many of these treatments focused or
will focus on removal of pinyon and juniper woodlands
(20%) and sagebrush restoration (27%).
Potential Response of Reptiles to Sage‐Grouse
Management Actions
We did not locate any studies documenting the effects of
sage‐grouse‐specific habitat restoration or management on
reptiles. We found 9 studies that examined our group I or II
species regarding response to land treatments that were
somewhat similar to those implemented for sage‐grouse:
seeding to control invasives (crested wheatgrass [Agropyron
cristatum] seeding), targeted grazing to reduce risk of
wildfire (grazing), and pinyon‐juniper removal to reduce
Table 2. Land treatments conducted in the western United States, 1990–2014, on lands administered by the Bureau of Land Management within and
immediately adjacent to the 2014 range of the greater sage‐grouse in the United States. Treatment counts are reported from treatments in the Land
Treatment Digital Library (Pilliod and Welty 2013) that have a polygon, point, or line feature, but area treated (ha) is reported only from treatments with
polygon features. We calculated the percent of treated area by dividing the area for a treatment category by the area treated. We included only land
treatments with confirmed implementation; thus, these counts and areas represent minimums.
Confirmed implemented treatments Treatments for sage‐grouse
Treatment category Treatment count Area treated (ha)% of treated area Treatment count Area treated (ha)% of treated area
Seedings 2,657 2,556,361 65 1,072 1,144,777 70
Prescribed burns 910 400,472 10 177 106,834 6
Vegetation disturbance
a
914 238,553 6 233 82,491 5
Herbicide 691 356,168 9 161 121,399 7
Other 554 159,434 4 201 111,665 7
Soil disturbances
b
427 160,848 4 135 38,835 2
Juniper or pinyon‐juniper removal 317 72,913 2 116 37,802 2
Total 6,470 3,944,749 100 2,095 1,643,804 100
a
Mastication, thinning, other than juniper and pinyon‐juniper removal.
b
Plowing, chaining.
Pilliod et al. •Sage‐Grouse as an Umbrella Species for Reptiles 485
wildfire risk or limit predator perching and nesting habitat
(conifer felling; Table 3). About half of these studies com-
pared treated to untreated areas or made before‐after com-
parisons, whereas the remaining studies only documented
habitat associations. Careful interpretation of these findings
is warranted relative to the experimental design, the level
inference, the specifics about each treatment, the landscape
context, and how these studies assessed species‐habitat
relationships.
With such limited information and uncertainty about
reptile responses, future restoration projects may also want
to prioritize monitoring of species that could occur in a
project area on the basis of their conservation status
(Table 4). Of the 70 reptile species with ranges overlapping
the greater sage‐grouse, 66 are currently considered stable
across their geographic range (IUCN least concern;
Table S3, available online in Supporting Information). The
remaining 4 include 2 lizards, a turtle, and a tortoise. The
Gila monster (Heloderma suspectum) is listed as near
threatened—decreasing and the panamint alligator lizard
(Elgaria panamintina) is listed as vulnerable—decreasing,
but neither of these species have distributions that overlap
with the range of sage‐grouse by >10% and their habitat
associations do not overlap with those of the bird
(i.e., group IV species; Fig. 3, Tables S2, S3). The north-
western pond turtle (Actinemys marmorata) and Mojave
desert tortoise (Gopherus agassizii) are listed as vulnerable,
but they also did not meet our criteria for inclusion under
the sage‐grouse umbrella (Tables S2, S3). The Mojave
desert tortoise is the only species of our 70 that is listed as a
threatened species under the ESA. Therefore, most of the
reptiles in the range of the sage‐grouse are offthe radar for
conservation priorities in sagebrush ecosystems because they
are considered stable globally and have no federal mandates
for protection in the United States. Several species,
however, have state conservation status (Table 4).
DISCUSSION
Our findings confirm that the greater sage‐grouse qualifies
as a potential umbrella species for sagebrush ecosystems,
meeting the basic requirement for having a large dis-
tribution relative to those of potential beneficiary species
under the umbrella (Wilcox 1984). The greater sage‐grouse
range in western North America is shared with a wide va-
riety of vertebrates, with estimates ranging from 250 to
350 species (Sands et al. 1999), including 70 reptile species
that we identified in our assessment. This suggests that
20–28% of vertebrates that co‐occur with sage‐grouse, and
potentially fall under the sage‐grouse conservation umbrella,
are reptiles, specifically snakes and lizards.
Other sage‐grouse umbrella assessments have included
reptiles but only for a subset of species that were considered
sagebrush obligates or associates (Rowland et al. 2006,
Carlisle et al. 2018b, Runge et al. 2019), and often with
results that were inconsistent with each other and our
findings. We examine some of these similarities and
differences more closely.
Table 3. Reptile associations with land treatments typically implemented for greater sage‐grouse in sagebrush ecosystems of the western United States using literature, 1970–2019. We included species if they overlap
with greater sage‐grouse by >10% of their modeled distributions (i.e., group I and II species, 2008–2016) and have some literature available on associations with treatments. For each treatment, we indicate a positive
association (P), a negative association (N), no association observed (0), or no information available from the literature (.).
Common name Crested wheatgrass seeding Grazing
a
Conifer felling Citations
Pygmy short‐horned lizard N P . Reynolds (1979), Reynolds and Trost (1980), Werschkul (1982)
Common sagebrush lizard N N P Reynolds (1979), Reynolds and Trost (1980), Werschkul (1982), James and M'Closkey (2003),
Beever and Brussard (2004)
Greater short‐horned lizard N . . Hanser et al. (2011)
Western fence lizard N 0 . Werschkul (1982), James and M'Closkey (2003), Beever and Brussard (2004)
Western rattlesnake N . . Jochimsen et al. (2014)
Desert horned lizard N P, N . Werschkul (1982), Beever and Brussard (2004), Newbold and MacMahon (2008)
Common side‐blotched lizard N N P Werschkul (1982), James and M'Closkey (2003), Beever and Brussard (2004)
Gophersnake N . . Jochimsen et al. (2014)
Great Basin collared lizard N P . Werschkul (1982), Beever and Brussard (2004)
Long‐nosed leopard lizard N . . Werschkul (1982)
Tiger whiptail N P, N . Werschkul (1982), Beever and Brussard (2004), Germano et al. (2012)
a
Grazing treatments are experimental and vary by study. Review of the treatment specifications is important for interpretation of grazing effects and effects of other treatments.
486 The Journal of Wildlife Management •84(3)
Reptile Species That Might Benefit Under the
Sage‐Grouse Conservation Umbrella
Our findings suggest that 37% of reptile species in the
western United States and Canada have ranges that fall
within at least some portion of the range of the greater sage‐
grouse, implying that about a third of all reptiles in the
region could benefit, at least to some extent, if sage‐grouse
habitat is protected or improved. We suspect the percentage
of potential beneficiary reptile species may be closer to
7–12% (14–22 species) given the habitat requirements and
distribution overlap thresholds (>10%) that we identified
from the pool of 190 reptile species within the range of
the bird.
A previous assessment concluded that management of
sage‐grousehabitatintheGreatBasinlikelywouldoffer
little conservation benefit for reptiles because of dissim-
ilar land cover affinities and small range overlaps between
reptiles and sage‐grouse compared to other vertebrates
(Rowland et al. 2006). Using independent data sources,
both Rowland et al. (2006) and our study reported that
the common sagebrush lizard, considered a sagebrush
obligate by some (Rowland et al. 2006), was likely to
benefitfromsage‐grouse conservation on the basis of
range overlap and habitat preferences. Our assessment,
however, was that the pygmy short‐horned lizard was the
most likely to benefitunderthesage‐grouse umbrella,
based on range overlap and habitat similarity with
sage‐grouse. Nevertheless, both the pygmy short‐horned
lizard and common sagebrush lizard are associated with
sagebrush communities, especially where understory is
sandy and free from dense grasses that impede their for-
aging movements (Reynolds 1979, Green et al. 2001,
James and M'Closkey 2002).
One difference between other sage‐grouse umbrella spe-
cies assessments and ours is that no other study has exam-
ined all reptile taxa across the entire range of the greater
sage‐grouse. This difference can influence study conclusions
because of local (e.g., state) versus regional (multi‐state or
range‐wide) differences in species compositions and associ-
ations with sage‐grouse habitat. For example, in Wyoming,
researchers concluded that, among all reptiles in the
state, only the greater short‐horned lizard would benefit
from the protection of sage‐grouse conservation areas
(Carlisle et al. 2018b). Greater short‐horned lizards are as-
sociated with big sagebrush in Wyoming (Hanser et al.
2011) and we also identified it among the group I benefi-
ciary species as third most likely to benefit across the entire
range of the greater sage‐grouse based on area and land
cover overlap characteristics. Comparisons of state‐specific
to range‐wide assessments may be informative to under-
stand relative importance of portions of species' ranges, and
how these may contribute to the whole. Afterall, reptiles
in the United States are managed in the public trust by
state governments and thus state‐level assessments are
Table 4. The conservation status of the 22 reptile species that overlap with the 2014 range of the greater sage‐grouse by >10% of their distribution in the
western United States, 2008–2016. Global and national rankings include International Union for the Conservation of Nature (IUCN), Committee on the
Status of Endangered Wildlife in Canada (COSEWIC), and the Endangered Species Act (ESA) of the United States. Asterisks indicate the 14 species that
are most likely to benefit under the conservation umbrella for greater sage‐grouse on the basis of both proportion of their distribution overlapping with sage‐
grouse and habitat similarity with sage‐grouse (group I species). For the United States, we list only the western states where sage‐grouse occur and have
species status of S1–S3, or I–II. State rankings include critically imperiled (S1), imperiled (S2), rare or uncommon (S3), not rare and apparently secure (S4),
and demonstrably widespread (S5) in Idaho, Montana, Nevada, Utah, and Washington. Species designations in North Dakota and South Dakota are
described as levels with the following definitions: I =high level of conservation priority, II =moderate level of conservation priority or a high conservation
priority but with substantial funding available for the species, III =moderate level of conservation priority but are believed to be peripheral or non‐breeding in
North Dakota. Oregon species are listed as sensitive or sensitive‐critical. Wyoming species have the addition of a state level endangerment designation, such
as those listed under the ESA. Wyoming species designations tiers are I =highest priority, II =moderate priority, and III =lowest priority. A dash indicates
no available information.
Common name IUCN and NatureServe COSEWIC ESA State status*
Pygmy short‐horned lizard* Least concern Extirpated Not listed II (ND), S3 (WA)
Common sagebrush lizard* Least concern —Not listed S2 (SD), S3 (WA)
Greater short‐horned lizard* Least concern Special concern Not listed S2 (SD), II (WY), S3 (ID), S3S4 (NV)
Northern rubber boa* Least concern Special concern Not listed II (WY), S3S4 (NV)
Striped whipsnake* Least concern —Not listed S1 (WA)
Western fence lizard* Least concern —Not listed —
Desert nightsnake* Least concern Endangered Not listed —
Western rattlesnake* Least concern Threatened Not listed Sensitive‐critical (OR)
Desert horned lizard Least concern —Not listed —
Terrestrial gartersnake* Least concern —Not listed —
Common side‐blotched lizard* Least concern —Not listed S3 (WA)
Gophersnake* Least concern —Not listed —
Great Basin collared lizard Least concern —Not listed S2 (ID)
Long‐nosed leopard lizard Least concern —Not listed —
Prairie rattlesnake* Least concern Special concern Not listed —
Plains hog‐nosed snake Least concern —Not listed I (ND), II (WY), S2 (MT)
North American racer* Least concern —Not listed —
Western skink Least concern Special concern Not listed —
Plateau fence lizard* ——Not listed —
Tiger whiptail Least concern —Not listed —
Plains gartersnake Least concern —Not listed —
Arizona mountain kingsnake Least concern —Not listed S2 (NV), S3 (UT)
Pilliod et al. •Sage‐Grouse as an Umbrella Species for Reptiles 487
meaningful, especially for species not listed under the ESA
(Tables 4 and S3).
Although we distinguished group I and II species for
purposes of ranking, we suspect that group II species might
also benefit from sage‐grouse conservation on more of a
regional scale or as spillover from adjacent habitat restora-
tion activities even though their land cover associations are
relatively different from those of the sage‐grouse. Similar to
our findings, Rowland et al. (2006) identified some of our
group II species as having habitat preferences that were not
particularly similar to those of the sage‐grouse, or in the case
of the Great Basin collared lizard, habitat preferences were
distinct from those of sage‐grouse. Many of these group II
species are active foragers that need open interspaces be-
tween shrubs and the structure provided by shrubs, shrub
islands, and rock outcroppings (Werschkul 1982). The re-
liance of species on microhabitats complicates broad‐scale
range overlap and umbrella species assessments (Rowland
et al. 2006) and can be a shortcoming of overlap studies
such as ours.
Reptile Species That Are Likely to Overlap with or
Could Be Disproportionately Affected by Management
Actions Targeting Sage‐Grouse
Management actions targeting sage‐grouse habitat where
pygmy short‐horned lizards occur could have a dis-
proportionately large effect on this lizard because it has a
small distribution, the majority of which lies within the
sage‐grouse range. Eight other group I species also warrant
attention because they have relatively small distribution sizes
and 25–40% of their distribution area overlap with the sage‐
grouse range. Most notable in this group are the common
sagebrush lizard, northern rubber boa, and greater short‐
horned lizard, which ranked highly from both the sage‐
grouse perspective (Fig. 4A) and the reptile perspective
(Fig. 4B). Range size is one of the most important pre-
dictors of extinction risk among reptiles (Böhm et al. 2016).
Thus, a manager may want to be particularly aware of the
habitat requirements for species with limited distributions at
the state or regional level when considering habitat man-
agement actions where they are likely to occur.
Central to prioritizing species under the sage‐grouse um-
brella is also understanding their distribution beyond the
range of the sage‐grouse. A good example of this is the
gophersnake, which has a distribution overlapping 88% of
the range of the greater sage‐grouse, but this portion com-
prises only 15% of the snake's distribution. This pattern was
also evident in a study in Wyoming where the gophersnake
overlapped with 29% of the reserves created for sage‐grouse,
but these greater sage‐grouse conservation areas did not
provide a protected area for gophersnakes that was better
than one selected at random (Carlisle et al. 2018b). Species
such as the gophersnake could easily fall in the trap of
dismissal by resource managers because of their patterns of
distributional overlap with sage‐grouse. In other words, an
overlap of 15% range‐wide or nearly 30% within protected
areas of a state may not be considered particularly mean-
ingful for the conservation of a widely distributed reptile
species. From a smaller scale perspective (e.g., such as a
county or even a state), however, the habitat management
actions conducted in the area where the species occurs could
still have major implications for the reptile species (Pike
et al. 2011). This exemplifies how studies of species overlap
can be insightful and misleading and how the task of
ranking potential beneficiary species under single‐species
umbrella management is multi‐faceted, complex, and re-
quires careful consideration of scale and local or regional
context.
Management Actions Targeting Sage‐Grouse and
Potential Reptile Responses
Land treatments conducted from 1990 to 2014 were pri-
marily seedings. In the Great Basin, previous assessments
have found that sagebrush was the most frequently seeded
shrub and crested wheatgrass was the most frequently
seeded grass (Pilliod et al. 2017). About a quarter of the
seeding treatments in the range of the sage‐grouse have
included crested wheatgrass, which could be problematic for
snakes and lizards who appear to avoid these non‐native
grasslands (Reynold and Trost 1980; Table 3) or for those
that require shrub canopies, the development of which may
be hindered by dense stands of highly competitive grasses
such as crested wheatgrass (Gunnell et al. 2010, Knutson
et al. 2014). Some of these seedings, however, are intended
to reduce non‐native annual grasses, such as cheatgrass,
which for similar reasons, could be potentially more prob-
lematic than crested wheatgrass, particularly for lizards
(Green et al. 2001, Newbold 2005, Rieder et al. 2010,
Runge et al. 2019). The goal of restoring native shrubland
vegetation following human or natural disturbances across
the range of the sage‐grouse provides an exciting oppor-
tunity to better assess how reptile species and communities
(e.g., lizard‐eating snakes such as the striped whipsnake or
desert nightsnake) respond to such intervention.
The next step in predicting how species might benefit
under the sage‐grouse umbrella is to improve understanding
of how species might be affected by habitat modifications
that are likely to occur under single‐species management.
Ideally, empirical evidence would be available from con-
trolled, experimental studies of management actions aimed
at restoring sage‐grouse habitat for each of the 14 to
22 beneficiary reptile species that we identified (i.e., group I
and II species). A review of the literature, however, revealed
that few studies exist, despite the considerable legacy of land
treatments conducted for sage‐grouse on public and private
lands. This lack of information on population responses to
habitat management and loss is typical for reptiles in the
United States and around the world and it presents a major
conservation challenge (Böhm et al. 2013).
Although the available information on reptile responses to
sage‐grouse habitat management is weak to non‐existent
presently, many of the land cover associations between
reptiles and sage‐grouse that we identified were somewhat
similar. In other words, the correlative patterns (Table 3) for
reptiles are fairly representative of greater sage‐grouse hab-
itat preferences, including preferring intact stands of
488 The Journal of Wildlife Management •84(3)
sagebrush with relatively low amounts of introduced grasses
(e.g., crested wheatgrass, cheatgrass) or conifers (Arkle et al.
2014, Farzan et al. 2015). Conifer felling and removal (i.e.,
of pinyon pine and juniper trees encroaching into sage-
brush) is one of the most common habitat management
actions used to reduce perching and nesting structures for
avian predators of sage‐grouse and reduce wildfire risk
(Farzan et al. 2015, Bombaci and Pejchar 2016, Holmes
et al. 2017). James and M'Closkey (2003) reported a pos-
itive response from 2 lizard species within our group I list
(common sagebrush lizard and common side‐blotched
lizard) when the trees were cut and left on site because
these species preferred dead over live trees regardless of
whether they were standing or prone. Given their tendency
to use pinyon and juniper trees for perching, removal
(instead of just felling) of this habitat structure could have a
negative effect on some of these lizards (Morrison and Hall
1999). Removal of conifers to improve sage‐grouse habitat,
however, could also benefit many other lizard and snake
species that prefer open sagebrush shrublands and are also
susceptible to avian predators. Finally, similar to sage‐
grouse, reptiles appear to have mixed responses to grazing
because of variation in timing, frequency, and duration of
grazing, and livestock type, stocking rate, and other factors
(Beck and Mitchell 2000, Dettenmaier et al. 2017).
We found no published studies examining the effects of
prescribed fire on our group I or II reptile species, although
this treatment type is generally uncommon within the range
of the sage‐grouse. Research in low‐elevation sagebrush
steppe suggests that post‐wildfire landscapes may support
fewer tiger whiptails and striped whipsnakes, and more
North American racers (Cossel 2003). It is difficult to
compare effects of prescribed fire and wildfire and these
reptiles may also be responding to the loss of shrublands and
conversion to annual grasslands more than the direct effects
of fire. In fact, none of the studies we examined assessed
effects of restoration actions relative to a no‐action alter-
native in an experimental design. This is important because
our data show that most land treatments are implemented in
response to wildfire (e.g., post‐fire seeding) to mitigate
against an ecological‐state transition into an undesirable
habitat condition. In other words, it is possible that no‐
intervention for sage‐grouse could also have ecological im-
plications for reptiles, especially when rates of shrubland
recovery are so slow (Lesica et al. 2007, Knutson et al. 2014,
Avirmed et al. 2015).
Thus, because of insufficient information, we could not
make defendable conclusions regarding the effects of spe-
cific management actions on reptiles, as a whole or for in-
dividual species. The effects of habitat management actions
on reptiles will likely depend on the disturbance history of a
site, its condition prior to intervention, and the species
present or available to colonize or recolonize from adjacent
areas. This variability complicates study‐level generalities for
specific treatment effects on individual species. Overall,
however, the agreement among species in their response to
habitat management as reported in the literature (Table 3)
suggests that habitat management actions intended for
sage‐grouse may have similar responses by grouse and rep-
tiles. If true, this would fulfill the third criteria of the um-
brella species concept; restoration or management actions
targeting the umbrella species should also benefit, or at least
not negatively affect, co‐occurring species.
Although the reptile species in the range of the greater
sage‐grouse are apparently stable globally, several species
may warrant attention because of regional declines, other
threats, rarity, or data deficiency. For example, of the
14 group I species that we identified as potential benefi-
ciaries under the sage‐grouse umbrella, 6 were ranked as
either extirpated, endangered, threatened, or of special
concern in Canada and 7 had conservation status within
specific states (Table 4). Many of these conservation con-
cerns appear to be associated with the periphery of species'
ranges. Still, documented declines, rarity, and a lack of
empirical information about the status of most species
suggests that keeping our short‐list of species on the watch
list for several states is warranted. The lack of data on status
and trends for most reptiles is particularly concerning.
MANAGEMEMT IMPLICATIONS
We anticipated providing a definitive list of reptile species
that could be classified as sagebrush obligate or sagebrush
associate and thus would be included in various conservation
efforts across the sagebrush biome. We found, however, that
this simplistic designation is not so useful. Instead, we
identified 14 (group I) reptile species that warrant additional
consideration when planning habitat restoration or making
management decisions within sage‐grouse habitat. We
consider this list a reasonable starting point given the range,
distribution, and habitat associations of lizards, snakes,
turtles, and tortoises within the range of the greater sage‐
grouse. Of this list, we found that the pygmy short‐horned
lizard and common sagebrush lizard stood out from the
others, warranting closer attention. Currently, however,
there is insufficient evidence to assess the specificeffects of
sage‐grouse habitat management actions on these or any of
the lizard and snake species across the western United
States. Although it is optimistic to expect that habitat
management decisions intended for sage‐grouse will benefit
these and other species under the sage‐grouse umbrella,
further empirical evidence is needed to confirm this
expectation.
ACKNOWLEDGMENTS
Any use of trade, product, or firm names is for descriptive
purposes only and does not imply endorsement by the
United States Government. We thank L. S. Schueck for
assistance with GAP data and J. L. Welty for assistance
with land treatment information. Two anonymous reviewers
and L. B. Evers provided helpful comments on earlier ver-
sions of this manuscript. Funding for this project was pro-
vided by the Western Association of Fish and Wildlife
Agencies, the United States Geological Survey Forest and
Rangeland Ecosystem Science Center, and the USFS
Pacific Northwest Research Station.
Pilliod et al. •Sage‐Grouse as an Umbrella Species for Reptiles 489
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