HABITAT SELECTION OF THE GREAT BASIN SPADEFOOT (SPEA INTERMONTANA)
IN THE GRASSLANDS OF BRITISH COLUMBIA
by
JO-ANNE HALES

BNRS, Thompson Rivers University, 2009

A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS
FOR THE DEGREE OF
MASTER OF SCIENCE IN ENVIRONMENTAL SCIENCES

in the Department of Natural Resource Sciences

Thesis examining committee:

Karl Larsen (PhD), Professor and Thesis Supervisor, Natural Resource Sciences
Nancy Flood (PhD), Senior Lecturer and Committee Member, Biological Sciences
Tom Pypker (PhD), Associate Professor and Committee Member, Natural Resource Sciences
Kristiina Ovaska (PhD), External Examiner, Consultant at Biolinx Environmental Research
Ltd., Research Associate at Royal British Columbia Museum

July 2018
Thompson Rivers University

©Jo-Anne Hales, 2018

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Thesis Supervisor: Karl W. Larsen (PhD)
ABSTRACT
Wetlands and their surrounding upland areas provide crucial habitat for the Great Basin
Spadefoot (Spea intermontana), a species at risk in the grasslands of the southern interior of
British Columbia (BC), Canada. Understanding habitat selection and how these animals
respond to change is crucial in the creation and implementation of conservation plans for this
species. I studied the habitat selection of the Great Basin Spadefoot in the grasslands
surrounding the New Gold - New Afton Mine, located approximately 10 km from Kamloops,
BC. The objectives of my study were to (1) determine what type of breeding ponds
spadefoots were using, (2) determine if artificial ponds could be used as a management tool,
(3) determine desirable adult daytime retreat site features and decipher movement patterns to
predict habitat use, and (4) determine microhabitat preferences of newly-metamorphosed
spadefoots. To analyze breeding pond selection, 18 ponds on the mine site were surveyed.
There was no significant difference between breeding (n=10) and non-breeding ponds (n=8)
for any of the water or pond characteristics measured. Eight artificial ponds were also
constructed in November 2013, and spadefoots bred in four of the eight novel ponds the
following spring. Throughout the 2013 and 2014 activity seasons, radio-telemetry was used
to locate daytime retreat sites and monitor movements of 33 adult animals. The maximum
and mean maximum straight-line distance (m) travelled by adult spadefoots from their
breeding ponds was 506 m and 240 m  146 SD. The telemetered animals relocated between
retreat sites, often returning to burrows used previously. There was no significant difference,
in respect to soil moisture, aspect, slope or percent ground cover, between used and available
habitat plots. I also conducted a microhabitat study, within artificial enclosures, that revealed
that newly-metamorphosed spadefoots preferred terrestrial habitat with moist cover. Aside
from this narrow window of vulnerability, my study indicates that this species has the ability
to inhabit and persist in drier, altered grassland habitats in this region through a very plastic
response to a wide range of conditions.
keywords: Great Basin Spadefoot, Spea intermontana, British Columbia, radio-telemetry,
metamorph, plasticity, habitat, disturbance, artificial ponds

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TABLE OF CONTENTS
ABSTRACT .................................................................................................................................. i
TABLE OF CONTENTS ................................................................................................................. ii
ACKNOWLEDGEMENTS.............................................................................................................. iv
DEDICATION .............................................................................................................................. v
LIST OF FIGURES ....................................................................................................................... vi
LIST OF TABLES ...................................................................................................................... viii
CHAPTER 1. INTRODUCTION ...................................................................................................... 1
Study Species ........................................................................................................................ 2
Study Area ............................................................................................................................ 6
Climate .................................................................................................................................. 6
Objective ............................................................................................................................. 10
Literature Cited ................................................................................................................... 14
CHAPTER 2. ADULT HABITAT SELECTION OF THE GREAT BASIN SPADEFOOT (SPEA
INTERMONTANA) WITHIN DISTURBED ARID GRASSLANDS ........................................................ 16
Introduction ......................................................................................................................... 16
Methods............................................................................................................................... 18
Results ................................................................................................................................. 23
Discussion ........................................................................................................................... 32
Literature Cited ................................................................................................................... 36
CHAPTER 3. MICROHABITAT SELECTION BY NEWLY-METAMORPHOSED GREAT BASIN
SPADEFOOTS (SPEA INTERMONTANA): A MICROCOSM STUDY .................................................. 42
Introduction ......................................................................................................................... 42
Methods............................................................................................................................... 44
Results ................................................................................................................................. 49
Discussion ........................................................................................................................... 50
Literature Cited ................................................................................................................... 53
CHAPTER 4. CONCLUSION ....................................................................................................... 57
Summary ............................................................................................................................. 57
Management Implications ................................................................................................... 58

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Limitations and Future Research Priorities......................................................................... 60
Concluding Remarks ........................................................................................................... 62
Literature Cited ................................................................................................................... 62
APPENDIX A. MAP OF ARTIFICIAL POND LOCATIONS ............................................................. 65
APPENDIX B. ARTIFICIAL POND CONSTRUCTION .................................................................... 66
APPENDIX C. SPADEFOOT RELOCATION SUMMARY TABLE ..................................................... 67
APPENDIX D. RADIO-TELEMETRY DATA SUMMARY TABLE .................................................... 68
APPENDIX E. NEW GOLD - NEW AFTON MINE GREAT BASIN SPADEFOOT AND WESTERN TOAD
MANAGEMENT PLAN – CREATED BY AUTHOR ......................................................................... 70

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ACKNOWLEDGEMENTS
I would like to thank my supervisor, Dr. Karl Larsen, for teaching me a very important
lesson: always make time for a beer. His knowledge, advice and encouragement throughout
this project were invaluable, and for that I am grateful. Thank you to my committee
members, for patiently seeing this project to completion.
A huge thanks to my little spadefoots; although involuntary participants, they were extremely
valuable and super cute. I would like to thank my research assistants, Katie Bennett and
Janessa Ekman, and my volunteers, Gerad Hales, Bevan Ernst and Jeff Morgan. The staff at
Tk’emlúps te Secwépemc (TteS), British Columbia Ministry of Forests, Lands, Natural
Resource Operations and Rural Development (MFLNRORD) and New Gold - New Afton
Mine were very supportive and provided encouragement throughout the duration of the
project. I extend extreme gratitude to my family and friends for their unwavering support,
even when they thought I was crazy for spending so much time on “toads.” To my kitties,
Purrvis and Mr. Meowgi, for your companionship and keen sixth sense of knowing when I
needed a break from the computer (or bout of procrastination). Last but certainly not least, I
want to thank my husband, Gerad Hales, for supporting me during the highs and lows, and
the laughter and tears. He provided many laughs throughout the entire roller-coaster ride,
keeping me sane through insanity.
This project was supported by TteS and New Gold - New Afton Mine. This work was
conducted under permit number KA13-86639, granted by the British Columbia
MFLNRORD and was approved by the Thompson Rivers University Animal Care
Committee, permit number 100349.

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DEDICATION
This thesis is dedicated to all the spadefoots who participated in this study to make this world
a little bit better and ‘hoppier’.

“Never think that you have learned
All there is to know.
That’s the surest way of all
Ignorance to show.”
“There are stranger things in the world to-day
Than ever you dreamed could be.
There’s beauty in some of the commonest things
If only you’ve eyes to see.”
“The Smiling Pool’s a nursery
Where all the sunny day
A thousand funny babies
Are taught while at their play.”
“Play a little, learn a little, grow a little too;
That’s what every pollywoggy tries his best to do.”
“The world is a wonderful great big place
And in it the young must roam
To learn what their elders have long since learned –
There’s never a place like home.”

-Thornton W. Burgess, The Adventures of Old Mr. Toad, 1943

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LIST OF FIGURES
Figure 1.1. Partially unearthed Great Basin Spadefoot at a daytime retreat site with
transmitter whip visible. Photo by author. ................................................................... 3
Figure 1.2. Distribution of the Great Basin Spadefoot in British Columbia (BCSIRAWG
2017). ............................................................................................................................ 4
Figure 1.3. The Great Basin Spadefoot: (A) in its aquatic habitat (B) in its terrestrial habitat,
and (C) newly-metamorphosed. Photos by author. ...................................................... 5
Figure 1.4. Google image of the study area on the New Gold - New Afton Mine property. .. 7
Figure 1.5. A variety of ponds located on the New Gold - New Afton Mine property: (A)
ephemeral, (B) ephemeral, (C) permanent, (D) artificial. Photos by author. .............. 8
Figure 1.6. A variety of habitat types on the New Gold – New Afton Mine property: (A)
rock, (B) sagebrush, (C) moss, (D) grass. Photos by author. ....................................... 9
Figure 1.7. Normals (1981-2010) (Government of Canada 2016) versus the 2013 Mean
Monthly Temperatures for New Afton Mine and the Kamloops Airport. .................. 11
Figure 1.8. Normals (1981-2010) (Government of Canada 2016) versus the 2014 Mean
Monthly Temperatures for New Afton Mine and the Kamloops Airport. .................. 12
Figure 1.9. Normals (1981-2010) versus the 2013 and 2014 Monthly Total Precipitation at
the Kamloops Airport. ................................................................................................ 13
Figure 2.1. Average daily surface and bottom temperatures (°C) measured using iButton
Thermochron® temperature data loggers between May and July 2014 comparing ten
breeding and eight non-breeding ponds. ..................................................................... 26
Figure 2.2. Google Earth image of the movement of spadefoot #2014M08 during the 2014
tracking season. Each marker represents each of the 28 relocations (in sequence) of
the individual, beginning with R1 and ending with R28. ........................................... 29
Figure 2.3. Google Earth image of the movement of spadefoot #2014M15 during the 2014
tracking season. Each marker represents each of the 12 relocations (in sequence) of
the individual, beginning with R1 and ending with R13. ........................................... 30
Figure 2.4. Google Earth image of the movement of spadefoot #2014F01 during the 2014
tracking season. Each marker represents each of the 20 relocations (in sequence) of
the individual, beginning with R1 and ending with R20. ........................................... 31
Figure 3.1. Location of metamorph microhabitat selection study in the semi-arid grasslands
in the Thompson River valley, approximately 10 km west of Kamloops, BC, Canada.
Photo by author. .......................................................................................................... 45
Figure 3.2. Schematic of artificial enclosure (i.e. microcosm) divided into four habitat types
(e.g. dry-bare, dry-cover, moist-bare, moist-cover) to investigate microhabitat
selection by newly-metamorphosed Great Basin Spadefoots. .................................... 47

vii
Figure 3.3. Microhabitat selection of metamorphic Great Basin Spadefoots within
microcosm arenas (n=130). The four available habitat types in each arena: dry-bare
(DB), dry-cover (DC), moist-bare (MB) and moist-cover (MC), are displayed on the
ordinate. The locations of the metamorphs were determined over three time periods:
At Release, 12 hours and 36 hours. After 36 hours, there is a clear indication that
moist-cover habitat is preferred over other habitat types. ........................................... 51

viii
LIST OF TABLES
Table 2.1. Comparison of pH, temperature (C), conductivity (μS/cm) and dissolved oxygen
(mg/L) measured in May and July 2014 between ten breeding and eight non-breeding
ponds. Mean values  standard deviation are shown, with minimum and maximum
values appearing in parentheses. ................................................................................. 25
Table 2.2. Comparison of pond elevation (m), hydroperiod (days), depth (m) and pond area
(ha) between ten breeding and eight non-breeding ponds. Mean values  standard
deviation are shown, with minimum and maximum values appearing in parentheses.
..................................................................................................................................... 25
Table 2.3. Comparison of percent cover of each of the four plant habitats (marginal,
emergent, submergent, bare) measured in May and July 2014 between ten breeding
and eight non-breeding ponds. Mean values  standard deviation are shown, with
minimum and maximum values appearing in parentheses. ........................................ 27

1
CHAPTER 1. INTRODUCTION
Understanding habitat selection and how animals respond to habitat change is crucial in the
creation and implementation of conservation plans for species at risk (Dodd 1993; Fellers
and Kleeman 2007). An inability to respond appropriately to changes (e.g. due to climate
change or human activity) in their environment, by making the right resource selection
decisions, can have detrimental effects on a species survival (Corn and Fogleman 1984; Huey
1991; Vos and Chardon 1998).
Disturbed landscapes (e.g. those resulting from mining, forestry or agricultural activity) have
been used for habitat selection studies to determine how individual animals respond to shortterm changes in their environment (Kaminski et al. 2007). Results of these studies have been
inconsistent. The results of Warren and Büttner’s (2008) study on a military training site in
Germany showed that response varied greatly among species: Natterjack Toads (Bufo
calamita) and Yellow-bellied Toads (Bombina variegata) thrived in breeding ponds with
high levels of disturbance, European Edible Frogs (Rana esculenta) were prevalent in ponds
with disturbance > 2 years old, and CommonTree Frogs (Hyla arborea), Smooth Newts
(Triturus vulgaris) and Alpine Newts (Triturus alpestris) were found in ponds with all levels
of disturbance. Even within a species, disturbance can have varying effects. For example,
Grizzly Bears (Ursus arctos) in west-central Alberta, Canada responded differently to mining
activity, depending on sex and whether the females were solitary or with cubs: males and
solitary females avoided disturbed areas while females with cubs favoured disturbed areas
(Cristescu et al. 2016).
Arid and semi-arid grasslands cover approximately 28% of the North American continent
and are susceptible to change (e.g. those caused by drought, fires, cattle grazing or
development) (Wikeem and Wikeem 2004) due to their typically warm temperatures, dry
climates and desirable locations (i.e. residential/industrial development of valley bottoms).
Average rainfall ranges from 250 to 500 mm and depending on location, temperatures can
reach as high as 38°C in summer months and as low as -40°C in the winter (Wikeem and
Wikeem 2004). Grassland wetlands and their surrounding upland areas provide crucial
habitat for a diverse number of species in arid systems, including those at risk (Findlay and
Houlahan 1997).

2
A variety of amphibians are able to withstand dry, hot environments. These include the Redspotted Toad (Anaxyrus puncatatus), which has a relatively large clutch size (~1,500 eggs)
and can metamorphose in eight days, and the Green Toad (Anaxyrus debilis), which can
tolerate extreme heat (i.e. 40°C; Griffis-Kyle 2016). Although some amphibians have
adjusted to living in arid environments, the majority of species rely on standing water for
reproduction, making them vulnerable to a decrease in the number of wetlands. Amphibian
populations are rapidly declining worldwide (Stuart et al. 2004) and could be partially
attributed to wetland loss and/or disturbance. Myers (1997) reported a worldwide wetland
loss of 50% over the last century. How various amphibians persist (or not) in response to
such rapid landscape changes in certain regions is not clearly understood.
In this thesis, I examine the ecology of the Great Basin Spadefoot (Spea intermontana)
within a disturbed landscape. In particular, I investigate the characteristics of spadefoot
breeding ponds and how both adult and newly-metamorphosed spadefoot tadpoles
(‘metamorphs’) use the terrestrial landscape. Little is known about the habitat preferences of
adult and metamorph spadefoots within the southern interior of British Columbia (BC), on
either undisturbed or disturbed landscapes. Highly disturbed areas, such as active and
reclaimed mine sites, provide optimal conditions for studying the ability of this species to
adjust to changes in its environment (from natural to ones evidencing anthropogenic
changes). My study was located within the southern interior grasslands of BC, where a 63%
decline in the number of ponds has been reported over the time period 1992-2012 (Coelho
2015). In Chapter 2, I compare ponds where spadefoots did and did not breed, test their
response to artificial ponds, and compare various features of used and available daytime
retreat sites. In Chapter 3, I investigate habitat preferences (at a microscale) of newlymetamorphosed spadefoots by conducting a novel microcosm experiment. Chapter 4
summarizes my study, highlights notable results and provides recommendations for
management plans and further studies.
STUDY SPECIES
The Great Basin Spadefoot (Figure 1.1) is a terrestrial, burrowing anuran on the provincial
Blue List (i.e. species considered vulnerable to human activities or natural events; BC CDC

3
2016). In 2007, COSEWIC assessed and designated the Great Basin Spadefoot “threatened”
in Canada, which influenced the “threatened” status under the Species at Risk Act
(Government of Canada 2018). The northernmost extent of its distribution is limited to the
dry grasslands in south-central BC (COSEWIC 2007; BCSIRAWG 2017) (Figure 1.2). This
species is an ideal subject for studying how animals can persist in harsh (i.e. arid ecosystems)
and changing conditions (e.g. due to climate change or human activity). They are able to
tolerate xeric conditions by efficiently absorbing the limited amount of moisture available in
the soil through their permeable skin (Ruibal et al. 1969). As well, they are able to exploit a
wide range of permanent and ephemeral ponds (i.e. irrigation ditches, roadsides, rain pools,
water depressions made by cattle, and pond edges; Buseck 2005; COSEWIC 2007),
effectively adjusting to changing environments.
Limited information is known regarding spadefoot habitat use (Dodd and Cade 1998;
BCSIRAWG 2017). They rely on two specific habitats to survive—aquatic for breeding and
tadpole development and terrestrial for aestivation, foraging and hibernation (Pearson 1955)
(Figure 1.3). Less is known about the habitat preference of metamorphs due to their size and
inability to carry transmitters within the limits of current technology (Figure 1.3).

Figure 1.1. Partially unearthed Great Basin Spadefoot at a daytime retreat site with
transmitter whip visible. Photo by author.

4

Figure 1.2. Distribution of the Great Basin Spadefoot in British Columbia (BCSIRAWG
2017).

5

A

B

C

Figure 1.3. The Great Basin Spadefoot: (A) in its
aquatic habitat (B) in its terrestrial habitat, and (C)
newly-metamorphosed. Photos by author.

6
STUDY AREA
The New Gold - New Afton Mine (New Afton) is an underground copper-gold mine located
approximately 10 km west of Kamloops in the southern interior of British Columbia, Canada
(50°39’38” N, 120°30’50” W; elevation 650-750 m ASL), in the Ponderosa Pine and
Bunchgrass biogeoclimatic zones (MFLNRORD 2016) in the Thompson-Pavilion grassland
region (Wikeem 2004). The site is dominated by Ponderosa Pine (Pinus ponderosa),
Bluebunch Wheatgrass (Agropyron spicatum) and Big Sagebrush (Artemisia tridentata)
(Meidinger and Pojar 1991; MFLNRORD 2016).
This landscape provides an excellent backdrop to study habitat use and persistence of the
Great Basin Spadefoot. The mine site is surrounded by agricultural activity and is situated
within the traditional territory of the Tk’emlúps te Secwépemc and Skeetchestn Indian
Bands, collectively referred to as the Stk’emlúpsemc of the Secwépemc Nation (SSN 2016).
The study site is affected by varying levels and types of disturbance. Focal study locations
on the site include the south-east portion of the mine site at Pothook Lake (telemetry) and the
restored wetland on the north end of the New Afton private property (metamorph study),
towards Kamloops Lake (Figure 1.4). The total area of the New Afton mining lease and all
other claims is 12,450.4 hectares (New Gold 2018), which contain a variety of aquatic and
terrestrial habitat types for the spadefoot (Figure 1.5 and Figure 1.6).
CLIMATE
The climate at New Afton is determined by the diverse geography of southern British
Columbia. New Afton lies in a dry valley bottom, typical of similar valleys in the southern
interior plateau, in the rain shadow of the westerly Coast Mountains (Chilton 1981). In this
area, summers are typically warm and dry, while winters tend to be cold (but mild) with little
precipitation (Chilton 1981).
Figures 1.7 and 1.8 compare the weather during my study years at New Afton to that
recorded at the Kamloops Airport weather station 30-year climate normals (1981-2010). The
New Afton weather station was activated in June of 2013. Throughout 2013 and 2014, New
Afton temperatures were consistently slightly lower than those recorded at the Kamloops
Airport, likely due to elevational differences (780 MASL versus 345 MASL, respectively).

7

Figure 1.4. Google image of the study area on the New Gold - New Afton Mine property.

8

A

B

C

D

Figure 1.5. A variety of ponds located on the New Gold - New Afton Mine property:
(A) ephemeral, (B) ephemeral, (C) permanent, (D) artificial. Photos by author.

9

A

B

C

D

Figure 1.6. A variety of habitat types on the New Gold – New Afton Mine property:
(A) rock, (B) sagebrush, (C) moss, (D) grass. Photos by author.

10
Overall, mean monthly temperatures for New Afton and the Kamloops Airport were
reasonably consistent with the 30-year normals for both 2013 and 2014. Although the New
Afton weather station did not collect precipitation data during the time of my study, monthly
total precipitation at the Kamloops Airport for 2013 and 2014 was 259.5 mm and 277.6 mm,
respectively, compared to the climate normals (1981-2010) of 279 mm (Figure 1.9).
OBJECTIVE
The overarching objective of my study was to understand how Great Basin Spadefoots use
this modified landscape within the arid grasslands of the Kamloops region. The results of the
study were used to address the following questions.
1.

Do adult spadefoots use specific types of breeding ponds? If we are able to
determine what type of breeding ponds they are using, we can administer the
appropriate conservation plans to protect, enhance or create those water
bodies.

2.

Will adult spadefoots colonize artificial ponds at this site? If so, can artificial
ponds be used as a management tool and what guidelines should be followed
when constructing these ponds?

3.

Once adult spadefoots leave the breeding ponds, are there specific features
they search for in daytime retreat sites? Are there movement patterns that can
help predict habitat use? If we are able to determine these features and
decipher movement patterns, we can administer appropriate conservation
plans to protect or enhance those features and usage areas.

4.

What are the microhabitat preferences of newly-metamorphosed spadefoots,
who rely on both aquatic and terrestrial habitats? Sustaining populations of
the spadefoot relies on ensuring a successful transition of metamorphs from
breeding ponds onto the terrestrial landscape.

Adult habitat selection, associated with questions one, two and three, are explored in Chapter
2 of this thesis. Chapter 3 is dedicated to question four, investigating microhabitat selection
of newly-metamorphosed spadefoots in a microcosm study.

11

Normals (1981-2010) versus 2013 Mean Monthly Temperatures
25

Mean Temperature (°C)

20

15

10

5

0

Normals
New Afton
Kamloops Airport

-5

-10
Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Month
Figure 1.7. Normals (1981-2010) (Government of Canada 2016) versus the 2013 Mean
Monthly Temperatures for New Afton Mine and the Kamloops Airport.

12

Normals (1981-2010) versus 2014 Mean Monthly Temperatures
25

Mean Temperature (°C)

20

15

10

5

0

Normals
New Afton
Kamloops Airport

-5

-10
Jan

Feb

Mar

Apr

May Jun

Jul

Aug Sep

Oct

Nov Dec

Month
Figure 1.8. Normals (1981-2010) (Government of Canada 2016) versus the 2014 Mean
Monthly Temperatures for New Afton Mine and the Kamloops Airport.

13

Normals (1981-2010) versus 2013 and 2014 Monthly Total Precipitation

Monthly Total Precipitation (mm)

60

50

40

30

20

10

0

Jan

Feb

Mar

Apr

May Jun

Jul

Aug

Sep

Oct

Nov Dec

Month
Normals
2013 Kamloops Airport
2014 Kamloops Airport

Figure 1.9. Normals (1981-2010) versus the 2013 and 2014 Monthly Total Precipitation
at the Kamloops Airport.

14

LITERATURE CITED
BC Conservation Data Centre (BC CDC). 2016. BC Species and Ecosystems Explorer. BC
Ministry of Environment. Victoria, BC. Available: http://a100.gov.bc.ca/pub/eswp/
(accessed Jan 13, 2016).
BC Ministry of Forests, Lands and Natural Resource Operations and Rural Development
(MFLNRORD). 2016. Biogeoclimatic Ecosystem Classification Program.
Available: https://www.for.gov.bc.ca/hre/becweb/resources/maps/index.html
(accessed Jan 14, 2016).
BC Southern Interior Reptile and Amphibian Working Group (BCSIRAWG). 2017.
Recovery plan for the Great Basin Spadefoot (Spea intermontana) in British
Columbia. Prepared for the BC Ministry of Environment. Victoria, BC. 40 pp.
Repr. of 1st ed., Southern Interior Reptile and Amphibian Working Group, Victoria,
BC. 40 p. (Orig. pub. 2016).
Buseck, R.S., D.A. Keinath, and M. Geraud. 2005. Species assessment for Great Basin
Spadefoot Toad (Spea intermontana) in Wyoming. United States Department of the
Interior, Bureau of Land Management. Cheyenne, Wyoming, USA.
Chilton, R. H. 1981. A summary of climate regimes of British Columbia. BC Ministry of
Environment. Victoria, BC.
Coelho, A.J.A. 2015. Assessing climate change induced declines in ponds in British
Columbia’s semi-arid grasslands. MSc thesis, Thompson Rivers University,
Kamloops, BC, Canada. Available:
http://www.tru.ca/__shared/assets/Coelho_thesis34900.pdf.
Corn, P.S., and J.C. Fogleman. 1984. Extinction of montane populations of the Northern
Leopard Frog (Rana pipiens) in Colorado. Journal of Herpetology. 18(2): 147-152.
COSEWIC. 2007. COSEWIC assessment and update status report on the Great Basin
Spadefoot (Spea intermontana) in Canada. Committee on the Status of Endangered
Wildlife in Canada. Ottawa. vii + 34 pp.
(http://www.sararegistry.gc.ca/virtual_sara/files/cosewic/sr_spea_intermontana_e.pdf).
Cristescu, B., G.B. Stenhouse, M. Symbaluk, S.E. Nielsen, and M.S. Boyce. 2016. Wildlife
habitat selection on landscapes with industrial disturbance. Environmental
Conservation. 43(4): 327-336.
Dodd, C.K. 1993. Cost of living in an unpredictable environment: The ecology of Striped
Newts Notophthalmus perstriatus during a prolonged drought. Copeia. 1993(3):
605-614.
Dodd, C.K., and B.S. Cade. 1998. Movement patterns and the conservation of amphibians
breeding in small, temporary wetlands. Conservation Biology. 12(2): 331-339.
Fellers, G.M., and P.M. Kleeman. 2007. California Red-legged Frog (Rana draytonii)
movement and habitat use: Implications for conservation. Journal of Herpetology.
41(2): 276-286.

15
Findlay, C.S., and J. Houlahan. 1997. Anthropogenic correlates of species richness in
southeastern Ontario wetlands. Conservation Biology. 11(4): 1000-1009.
Griffis-Kyle, K.L. 2016. Physiology and ecology to inform climate adaptation strategies for
desert amphibians. Herpetological Conservation and Biology. 11: 563-582.
Government of Canada. 2016. Climate. Historical Climate Data. Retrieved from
http://climate.weather.gc.ca/index_e.html#access.
Government of Canada. 2018. Species at Risk Public Registry. Species Profile for Great
Basin Spadefoot (Spea intermontana). Retrieved from http://www.registrelepsararegistry.gc.ca/species/speciesDetails_e.cfm?sid=539&docID=27 (accessed April
25, 2018).
Huey, R.B. 1991. Physiological consequences of habitat selection. American Naturalist.
Supplement: Habitat Selection. 137: S91-S115)
Kaminski, J.A., M.L. Davis, and M. Kelly. 2007. Disturbance effects on small mammal
species in a managed Appalachian forest. American Midland Naturalist. 157(2):
385-397.
Meidinger, D., and J. Pojar. 1991. Ecosystems of British Columbia. BC Ministry of
Forests. Victoria, BC. Special Report Series 6.
Myers, N. 1997. The rich diversity of biodiversity issues. In: Reaka-Kudla, M.L.,
D.E.Wilson, and E.O. Wilson (Eds.). Biodiversity II: Understanding and Protecting
Our Biological Resources. Joseph Henry Press: Washington, DC.
New Gold. 2018. New Afton Project Summary. Retrieved from
http://www.newgold.com/operations/new-afton/project-summary/default.aspx
(accessed Feb 3, 2018).
Pearson, P.G. 1955. Population ecology of the Spadefoot Toad, Scaphiopus h. holbrooki
(Harlan). Ecological Monographs. 25(3): 233-267.
Ruibal, R., L. Tevis Jr., and V. Roig. 1969. The terrestrial ecology of the Spadefoot Toad
Scaphiopus hammondii. Copeia. 1969(3): 571-584.
Stk’emlúpsemc te Secwépemc Nation (SSN). 2016. About Stk’emlúpsemc te Secwépemc
Nation. Retrieved from http://stkemlups.ca/about/ (accessed Jan 22, 2016).
Stuart, S.N., J.S. Chanson, N.A. Cox, B.E. Young, A.S.L. Rodrigues, D.L. Fischman, and
R.W. Waller. 2004. Status and trends of amphibian declines and extinctions
worldwide. Science. 306: 1783-1786.
Vos, C.C., and J.P. Chardon. 1998. Effects of habitat fragmentation and road density on the
distribution pattern of the Moor Frog Rana arvalis. Journal of Applied Ecology.
35(1): 44-56.
Warren, S.D., and R. Büttner. 2008. Relationship of endangered amphibians to landscape
disturbance. Journal of Wildlife Management. 72(3): 738-744.
Wikeem, B., and S. Wikeem. 2004. The grasslands of British Columbia. Grasslands
Conservation Council of British Columbia. Kamloops, BC. xvii + 479 pp.

16
CHAPTER 2. ADULT HABITAT SELECTION OF THE GREAT BASIN SPADEFOOT (SPEA
INTERMONTANA) WITHIN DISTURBED ARID GRASSLANDS
INTRODUCTION
Amphibian populations have been rapidly declining worldwide (Stuart et al. 2004), a
phenomenon largely attributed to landscape alteration, disturbance and contamination
(Knutson et al. 1999; Collins et al. 2003). The level of habitat disturbance on individual
amphibian species and their perseverance on the landscape is inconsistent: while disturbance
has been shown to negatively affect many amphibians, other studies have shown a positive
response (Warren and Büttner 2008) or little effect (Alford and Richards 1999). Blaustein
and Kiesecker (2002) even suggest that populations of the same species may respond
differently to similar disturbances. This irregularity requires further analysis to improve our
understanding of amphibian habitat selection and the persistence of species on disturbed
landscapes (i.e. arid grasslands).
Studies on many amphibian species have largely focused on breeding sites as opposed to
upland habitat use. This is not surprising since Myers (1997) reported a worldwide wetland
loss of 50% over the last century and Semlitsch and Bodie (1998) highlighted the
significance of small, ephemeral wetlands to amphibian species and biodiversity. Semlitsch
et al. (2015) studied 200 amphibian breeding ponds within the Midwestern US (with
anthropogenic and/or natural disturbance) and suggested that conservation and management
of amphibians should concentrate on intermediate-sized ponds (200 – 4000 m2) to increase
abundance, richness and diversity. Various breeding pond studies have occurred on
disturbed sites, yielding contrasting results: peat mining in Eastern Canada dramatically
modified bog habitat complexity which decreased Green Frog (Rana clamitans) and Wood
Frog (Rana sylvatica) populations, but increased the abundance of American Toads (Bufo
americanus; Mazerolle 2003). The effect of cattle disturbance on amphibian breeding habitat
also seems to vary with the species. American Toads were more numerous than Green Frogs
in cattle-grazed wetlands in Tennessee (Burton et al. 2009), while Roche et al. (2012)
reported no impacts from cattle grazing on the Yosemite Toad (Bufo canorus Camp). For
terrestrial species, upland habitat choice is as equally important as breeding pond selection
(Forester et al. 2006) yet has been insufficiently researched and poorly defined (Semlitsch

17
and Bodie 2003). Determining differences in all habitat types and species preference is
imperative in understanding species requirements and their persistence on a disturbed
landscape.
North American spadefoots (genera Scaphiopus and Spea) are generally associated with
drier, warmer habitats. They tolerate relatively dry conditions by having the ability to absorb
soil moisture through their permeable skin (Ruibal et al. 1969) and develop rapidly in
ephemeral ponds (COSEWIC 2007). Even though spadefoots have the quickest
metamorphic rates (time from egg-laying to metamorphosis) among anurans (16-28 days;
Bucholz and Hayes 2002) they can increase their rate of metamorphosis even more when
exposed to water and food restriction (Boorse and Denver 2004). Bucholz and Hayes (2002)
also determined that the optimal growth and development temperature for North American
spadefoots was 32°C, as compared to the European spadefoots (genus Pelobates; 28°C) and
the Parsley Frog (genus Pelodytes; 24°C). The spadefoot’s ability to adjust to unpredictable
environments has allowed it to persist in harsh conditions. This is an interesting
phenomenon, which is central to the conservation of the taxon. Despite this, there are limited
studies on spadefoot upland habitat use (Timm et al. 2014), particularly on disturbed
landscapes.
The Great Basin Spadefoot (Spea intermontana) ranges north into the grasslands of southcentral British Columbia (BC), an ecosystem historically subjected to a multitude of
disturbances including ranching, forestry and development (Wikeem and Wikeem 2004;
Klenner et al. 2008). This species is known to take advantage of a variety of habitats that are
in most cases undesirable or inhospitable to other species (Hovingh 1985; COSEWIC 2007;
BCSIRAWG 2017). This situation provides a suitable backdrop for examining habitat use
and persistence of the spadefoot in the face of environmental change. In BC, spadefoot
tadpoles have shown higher phenotypic plasticity than the Northern Red-legged Frog (Rana
aurora) and the Pacific Tree Frog (Pseudocris regilla) when subjected to warmer, temporary
pools (O’Regan et al. 2014). Adult spadefoots have been observed to utilize a variety of
permanent and ephemeral ponds (e.g. irrigation ditches, roadsides, rain pools, water
depressions made by cattle, and pond edges; Wright and Wright 1949; COSEWIC 2007).
Leupin et al. (1994) found spadefoots breeding in ponds in the BC Thompson Nicola region

18
with a wide range of pH, turbidity, temperature and vegetation levels. Auditory surveys
conducted by Kline and Packham (2009) in the BC Cariboo region recorded the presence of
calling spadefoots at ponds to delineate spadefoot occurrence. In addition, Garner (2012)
tracked the upland movements of the spadefoot near the northernmost limits of its range,
revealing core upland daytime retreat sites contained a high proportion of bare ground or
rock located across the landscape. Although spadefoots can be considered specialists in this
northern region due to their distribution within arid to semi-arid grasslands, they also appear
plastic in their larval development period, use of breeding sites and use of daytime retreat
sites within the ecosystem. Less than 1% of the land base in BC is a grassland ecosystem
(Wikeem and Wikeem 2004); this ecosystem is quickly deteriorating due to anthropogenic
and natural disturbance. Naturally, spadefoots in this region should be relatively resilient to
these alterations, but further research is needed to determine the perseverance of these
animals in this disturbed, arid ecosystem.
To add to our knowledge of how spadefoots thrive in a changing environment, I conducted
an ecological study on habitat use by this species across an altered and disturbed landscape.
My objectives were: (1) to compare ponds where the spadefoot did and did not breed, (2) to
create artificial ponds to see if and how rapidly spadefoots would colonize them and (3) to
compare used and available daytime retreat sites. Identifying features used by spadefoots for
selecting breeding ponds and daytime retreat sites will allow the crafting of appropriate
conservation plans to protect and enhance those features.
METHODS
Study Area
This study took place during the spadefoot active season (May—August 2013 and 2014)
within the arid grasslands of the Thompson River valley, approximately 10 km west of
Kamloops, BC, Canada (50°39’38” N, 120°30’50” W; elevation 650-750 m ASL). The
maximum daily temperature normal (1981-2010; May—August) in this area ranges between
21.5C and 28.3C, with minimums ranging from 7.7C and 13.4C, respectively. Total
average monthly rainfall at the valley bottom (elevation 345 m ASL) was 29.95 mm during
the same time period (Figures 1.7, 1.8, 1.9; Government of Canada 2017). The dominant

19
natural habitat types in this region are characterized by Ponderosa Pine (Pinus ponderosa),
Bluebunch Wheatgrass (Agropyron spicatum) and Big Sagebrush (Artemisia tridentata)
(Meidinger and Pojar 1991; MFLNRORD 2016).
The dominant causes of land disturbance (past and present) on the site are mining and cattle
grazing. Both natural and anthropogenic ephemeral and permanent ponds occur sporadically
across the landscape, providing a variety of water bodies (e.g. ephemeral ponds, ditches,
groundwater seepage ponds) that could potentially support spadefoot breeding. More details
on the site are provided in Chapter 1 of this thesis.
Breeding Pond Selection
Observations of ponds in 2013 determined which breeding and non-breeding ponds were
selected for the study in 2014. Since the focus of this study was on adult preferences, a pond
was categorized as being used for breeding if eggs, tadpoles and/or metamorphs were
detected during multiple diurnal surveys. Breeding period was determined by adult calling
(multiple nocturnal surveys), the presence of new eggs and/or recently hatched tadpoles in
the ponds. Spadefoot breeding was prolific on this site (e.g. occurred in roadside ditches,
flooded fields, in groundwater seepage ponds). Non-breeding ponds were less commonly
found, which limited the number of ponds that could be included in the study. Water
sampling and pond surveys were conducted at ten breeding and eight non-breeding ponds,
within an area ≈ 9 km2, to determine aquatic habitat preferences of the spadefoot. Eleven of
the 18 ponds were anthropogenic, six of which were breeding ponds. Both natural and
artificial ponds were monitored at least once a week to observe tadpole development. Stages
of larval development were recorded as per Gosner (1960).
Water Characteristics
In 2014, 36 water samples were taken using a YSI Professional Plus Handheld
Multiparameter Instrument and an Extech DO600 ExStik II handheld dissolved-oxygen
meter (18 samples in May; 18 samples in July). Date, time, location, pH, temperature (°C),
conductivity (uS/cm) and dissolved oxygen (mg/L) were recorded at all ponds following
previous studies that were focused on amphibian breeding pond habitat selection (Hazell et
al. 2004; Rannap et al. 2012; Drayer and Richter 2016). In addition to the temperature

20
recorded with a handheld device, four Maxim Integrated iButton Thermochron ® temperature
data loggers (model DS1921G) recorded temperature in each pond every two hours over the
duration of the field season (May through August 2014). A total of 797 iButton temperature
readings were collected. All data loggers were individually encapsulated in waterproof
cases. Two of the four data loggers at each pond were anchored just below the surface and
two at the bottom of each pond to obtain an overall average of pond temperature.
Pond Characteristics
In addition to temperature, monitoring of other pond characteristics was conducted at the 18
ponds across the site at the same time as the water sampling. Pond persistence (ephemeral or
permanent), hydroperiod (number of weeks containing water), origin (natural or
anthropogenic), depth (m), area (hectares) and percent cover of available plant habitat
(marginal, emergent, submergent, bare) were recorded.
An ephemeral pond was defined as a pond that typically dried out by mid-summer and a
permanent pond was one that contained water year-round during the study period.
Hydroperiod was defined as the period in which the soil area was waterlogged (MerriamWebster 2017). The majority of rainfall in the spring of 2014 (April through June) occurred
in May (41.2 mm; Government of Canada 2017). Therefore, for the purposes of this study, I
considered hydroperiod to have begun on May 1, 2014 for ponds that dried up before the end
of the summer.
Artificial Pond Construction
On November 9-10, 2013, four sites for pond creation were identified within a 2 km2 area of
the study site. These sites were chosen based on accessibility to roads, sufficient area to
accommodate the ponds and the ability of the machinery to avoid having substantial impact
on the environment. Pond excavation was conducted using a John Deere 225C LC hydraulic
excavator and a Caterpillar 304CR compact excavator. One pair of ponds was established at
each site (see location details in Appendix A). One pond was dug to a depth of 0.46 m and
the other to a depth of 0.8 m, to approximate a shallow ephemeral pond and a deeper
permanent pond, respectively. These depths were chosen based on observations of existing

21
natural ponds, and considerations of logistics and cost. The two ponds at each site were 10 m
apart and ≈ 2.5 m x 2.5 m in size.
Excavated ponds were lined with linear low-density polyethylene geomembrane liner
(LLDPE). The edges of the liner were buried to provide a seamless transition from the
surrounding area to the pond. Barbed-wire fences were constructed around the perimeter of
each pair of ponds to protect them from cattle. The ponds were left exposed over the
following winter (2013-2014) to collect precipitation.
On April 1, 2014 exposed liners along the edges of each pond were covered with burlap and
overlaid with approximately 1 cm of soil to simulate the natural edges of a pond. On April
30, 2014 the water level in each pond was augmented with nearby lake water to establish
water depths matching the 0.46 m and 0.8 m criteria (see above). A Ponderosa Pine tree
branch was submerged within each pond to provide a substrate for egg laying and cover for
tadpoles (Appendix B).
Movement and Daytime Retreat Site Selection
Radio-telemetry
Radio-telemetry was conducted to monitor terrestrial movements of adult spadefoots, and to
locate daytime retreat sites (Garner 2012) on land. Adult female spadefoots were caught by
hand at night between June 14—August 27 in 2013 and between June 16—24 in 2014.
Males were captured between June 13—August 27 in 2013 and May 14—June 17 in 2014.
Females were not captured or otherwise disturbed during the breeding period (defined by the
time which males were calling) to prevent undue stress. At capture, individuals were
weighed (g) on a portable electronic scale (Salter 1250BKEF) and measured (snout to vent
length (SVL)). Animals at least 13.5 g were outfitted with a Holohil 0.73 g BD-2X
transmitter (18-day battery life); individuals ≥ 20-22 g were equipped with 0.73 g or 0.83 g
Holohil BD-2 transmitter (18- or 26-day battery life, respectively). In all cases, the total
weight of transmitter and belt did not exceed 5% of the animal’s body weight (Resources
Inventory Committee 1998). Telemetered animals were located every 2—3 days. Locations
were flagged to permit future habitat measurements and GPS coordinates were taken with a
Garmin GPSMAP 62st handheld device. Date, time, location, animal ID, weather (sunny,

22
cloudy, dry, rainy), elevation (m) and daytime retreat type (self-made burrow or small
mammal burrow) were also recorded.
I categorized each daytime retreat site as a ‘self-made burrow’ if it was shallow (i.e. just
below surface), self-dug and did not connect to a small mammal tunnel. The ‘small mammal
burrow’ designation was applied to burrows within or connected to an active or inactive
small mammal tunnel or mound. Following Pearson (1955) and Garner (2012), core daytime
retreat sites were considered as those sites used multiple times in one season.
When transmitter batteries were nearing expiration dates, each telemetered animal was recaptured (nighttime period preferred to prevent disturbance to daytime retreat site), reweighed (g) and re-measured (SVL).
Percent Ground Cover and Soil Moisture
Habitat features were assessed at each daytime retreat site using a 1 m  1 m quadrat. Three
reference plots representing ‘available’ habitat were also established 5 m from each retreat
site at bearings of 0°, 120° and 240°. This scale would encompass and expand on the
microhabitat scale used in the Garner 2012 study. Within each plot, the percent cover for six
different ground types (bare, rock, litter, moss-lichen-fungi, grass-herb-shrub, coarse woody
debris) were recorded along with aspect and slope. In 2014, soil moisture (%) was recorded
in all plots (three readings per plot) using a soil meter (Campbell Scientific HS2 Hydrosense
II Display and Sensor). Care was taken to prevent injury to the buried animal when pushing
the instrument’s detection rods (12 cm length) into the soil. If the position of the animal
could not be confidently estimated (i.e. transmitter whip not visible or weak signal) soil
moisture was not recorded.
Statistical Analysis
Statistical analysis was performed using R 3.2.5 (R Core Team, 2015) using α=0.05 as a
guide to significance. Prior to conducting analysis, the categorical variables were
appropriately designated using the ordered (for ordered categorical (ordinal) variables) and
factor (for categorical (nominal) variables) functions (Bolker et al. 2011; Kabacoff 2011).

23
I tested for correlation between my predictor variables by calculating variance inflation
factors (VIF) as outlined by Zuur et al. (2012). As recommended by Zuur et al. (2010), I
used a VIF value of 3 as my pre-selected threshold (indicating no collinearity) versus the
higher (and more flexible) value of 10 used by Montgomery and Peck (1992).
I used the DAAG package (Maindonald and Braun 2010) to perform a multiple logistic
regression (MLR) to compare individual sampling periods (i.e. May, July) between breeding
and non-breeding ponds. To determine if there was a difference in use between (1) breeding
and non-breeding ponds and (2) used and available upland habitats, I conducted logistic
regression using a generalized linear mixed model (GLMM; Bolker et al. 2013) in the
glmmADMB package (Fournier et al. 2012; Skaug et al. 2015). My ‘grouping variables’
(pond ID and spadefoot ID) were treated as random effects and all explanatory variables
(habitat measurements) were considered fixed effects.
RESULTS
Breeding Pond Selection
Spadefoot breeding was detected in ten of the 18 water bodies I monitored at the study site
(seven breeding ponds throughout May, two ponds in mid-June and one pond at the end of
July). Metamorph emergence was observed at seven of ten breeding ponds, with the earliest
emergence detected on June 19 and the latest on August 22. At the other three breeding
ponds, the last observations of tadpoles (i.e. observations were discontinued) indicated
anuran development between Gosner stages 25 and 41 (Gosner 1960). An instance of
developmental plasticity was observed when tadpoles in an artificial ephemeral pond
developed more quickly and left their natal pond (after ~ 6 weeks of development) much
earlier than tadpoles hatched a week prior in the paired permanent pond (where some
remained until the end of August).
Water Characteristics
When I analyzed pH, temperature (C), conductivity (uS/cm) and dissolved oxygen (mg/L)
for May and July 2014 individually, all VIF values were < 3, indicating no collinearity; this
allowed all four covariates to be used in the analysis. The above-mentioned variables were

24
not significantly different between breeding and non-breeding ponds (all Ps ≥ 0.10). When
the data for both May and July were combined, dissolved oxygen was collinear to pH,
temperature (C) and conductivity (uS/cm), so it was removed from the analysis. Once
dissolved oxygen was removed, there was no significance for the combined data (all Ps ≥
0.84; Table 2.1). Over the duration of the field season, iButton temperature readings
revealed that daily average pond temperatures in breeding ponds were higher than nonbreeding ponds (Figure 2.1).
Pond Characteristics
Within pond characteristics measurements, VIF values resulted in only pond persistence and
area being removed due to collinearity, allowing elevation, hydroperiod, pond origin and
pond depth to be used in the analysis. None of the pond characteristics that I measured
differed significantly between breeding and non-breeding ponds (all Ps ≥ 0.97; Table 2.2).
The VIF values for vegetation were <3, indicating no collinearity, allowing all variables to be
used in the analysis. There was no significant difference in percent cover of plant habitat
measurements (marginal, emergent, submergent, bare) between breeding and non-breeding
ponds when May and July data were combined (all Ps ≥ 0.88; Table 2.3). When I analyzed
individual sampling periods, marginal and bare vegetation requirements were removed from
analysis in May, and emergent was removed from analysis in July, due to collinearity.
Subsequent analysis showed no significant difference between breeding and non-breeding
ponds (all Ps ≥ 0.16).
Artificial Pond Construction
Of the eight artificial ponds constructed, three permanent ponds and one ephemeral pond
experienced spadefoot breeding activity in the 2014 active season. My first observation of
spadefoot eggs was made on May 21 in a permanent pond, located furthest from known
breeding ponds (~ 1 km). This was followed by the detection of eggs in the paired ephemeral
pond on June 3. Spadefoot eggs were found in a permanent pond on June 10, approximately
2 km south of the May 21 observation and 375 m south of a known breeding pond. Newly
hatched eggs were last observed in a permanent pond on July 29, approximately 540 km
north west of a known breeding pond. I detected tadpoles reaching the metamorphic stage at

25
Table 2.1. Comparison of pH, temperature (C), conductivity (μS/cm) and dissolved oxygen (mg/L) measured in May and July 2014 between
ten breeding and eight non-breeding ponds. Mean values  standard deviation are shown, with minimum and maximum values appearing in
parentheses.
Sampling
Period

Pond Type

pH

Temperature (C)

Conductivity
(μS/cm)

Dissolved Oxygen
(mg/L)

May

Breeding

8.3  0.6 (7.1 – 9.1)

17.4  2.5 (13.5 – 22.3)

2506.5  3140.0 (109.0 - 8349.0)

5.8  1.0 (4.0 – 7.1)

Non-Breeding

8.2  0.7 (7.4 – 9.6)

16.7  3.5 (11.6 – 22.7)

4059.0  6327.1 (199.5 – 18832.0)

4.9  1.2 (2.8 – 6.3)

P-value

0.88

0.63

0.28

0.11

Breeding

8.6  0.7 (7.2 – 9.6)

27.8  3.1 (21.7 – 31.4)

5882.7  7239.3 (212.2 – 20525.0)

3.5  1.3 (1.3 – 5.8)

Non-Breeding

8.7  0.7 (7.8 – 9.8)

27.0  4.3 (19.1 – 32.1)

7779.9  12845.3 (493.9 – 38757.0)

2.2  1.2 (0.5 – 3.5)

P-value

0.35

0.27

0.29

0.10

Breeding

8.5  0.7 (7.1 – 9.6)

22.6  6.0 (13.5 – 31.4)

4194.6  5700.4 (109.0 – 20525.0)

4.7  1.6 (1.3 – 7.1)

Non-Breeding

8.4  0.7 (7.4 – 9.8)

21.9  6.6 (11.6 – 32.1)

5919.4  9968.7 (199.5 – 38757.0)

3.5  1.8 (0.5 – 6.3)

P-value

0.91

0.96

0.84

no value (collinear)

July

Combined

Table 2.2. Comparison of pond elevation (m), hydroperiod (days), depth (m) and pond area (ha) between ten breeding and eight non-breeding
ponds. Mean values  standard deviation are shown, with minimum and maximum values appearing in parentheses.
Pond Type

Elevation (m)

Hydroperiod (days)

Pond Depth (m)

Pond Area (ha)

Breeding

684.0  44.9 (586 – 750)

35.9  20.2 (11 – 52)

0.7  1.0 (0.1 – 3.5)

1.3  2.4 (0.002 – 7.9)

Non-Breeding
P-value

682.5  56.1 (589 – 761)
> 0.99

37.4  19.6 (11 – 52)
0.97

0.7  0.5 (0.1 – 1.6)
0.99

2.5  3.7 (0.002 – 9.2)
no value (collinear)

26

Average Daily Pond Temperatures
28
26

Temperature (°C)

24
22
20
18
16
14
Breeding Ponds - surface temperature
Breeding Ponds - bottom temperature
Non-breeding Ponds - surface temperature
Non-breeding Ponds - bottom temperature

12
10
05/12

05/26

06/09

06/23

07/07

Date

Figure 2.1. Average daily surface and bottom temperatures (°C) measured using iButton
Thermochron® temperature data loggers between May and July 2014 comparing ten breeding
and eight non-breeding ponds.

27

Table 2.3. Comparison of percent cover of each of the four plant habitats (marginal, emergent, submergent, bare) measured in
May and July 2014 between ten breeding and eight non-breeding ponds. Mean values  standard deviation are shown, with
minimum and maximum values appearing in parentheses.
Sampling
Period

Pond Type

Marginal (%)

Emergent (%)

Submergent (%)

Bare (%)

May

Breeding

5.0  4.5 (0 - 10)

19.0  26.5 (0 - 70)

7.8  13.4 (0 - 40)

65.1  39.6 (10 - 99)

Non-Breeding

5.0  5.3 (0 - 10)

19.4  24.3 (0 - 60)

8.1  9.2 (0 - 20)

62.6  40.9 (5 - 99)

P-value

no value (collinear)

> 0.99

0.96

no value (collinear)

Breeding

5.7  3.5 (1 - 10)

17.8  24.3 (0 - 60)

12.1  17.0 (0 - 45)

22.3  22.3 (0 - 55)

Non-Breeding

4.5  4.8 (0 - 10)

18.9  27.4 (0 - 60)

10.6  17.0 (0 - 50)

13.1  16.2 (0 - 50)

P-value

0.30

no value (collinear)

0.68

0.16

Breeding

5.4  4.0 (0 - 10)

18.4  24.8 (0 - 70)

10.0  15.0 (0 - 45)

43.7  38.2 (0 - 99)

Non-Breeding

4.75  4.9 (0 - 10)

19.1  25.0 (0 - 60)

9.4  13.3 (0 - 50)

37.9  39.5 (0 - 99)

P-value

0.88

0.92

0.99

0.92

July

Combined

28

all four ponds. All-natural ponds in the vicinity of the artificial ponds were utilized by cattle
and prone to desiccation.
Movement and Daytime Retreat Site Selection
Radio-telemetry, Percent Ground Cover, Soil Moisture
Twenty-three males (weight x̅= 17.2 + 1.5 SD, SVL x̅ =51.8 mm + 0.2 SD) and 10 females
(weight x̅= 22.4 g + 1.5 SD, SVL x̅ = 55.4 mm + 2.2 SD) were monitored with telemetry
throughout 2013 and 2014. The average weight of all adult spadefoots at capture (i.e. when
the transmitter was affixed) and at release (i.e. transmitter was removed) was 18.5 g  3.4 SD
(n=33). The telemetered animals were each tracked on average 23.7 + 18.1 SD days per
individual (min = 2, max = 63), which provided 111 daytime retreat sites for analysis. In
total, the telemetered spadefoots were relocated 442 times during this study and provided 781
tracking days. Average relocations per individual was 13.4 + 7.7 SD (min = 2, max = 28).
Overall, the maximum and minimum straight-line distance (m) travelled from a breeding
pond over the tracking seasons was 506 m and 0.8 m respectively. The mean of the
maximum straight-line distance travelled from the breeding pond of all telemetered
spadefoots (n=33) was 240 m  146 SD.
In 2014, five out of 20 telemetered spadefoots (4 males; 1 female) utilized core retreat sites,
exhibiting similar behaviour to that reported by Pearson (1955) and Garner (2012). This
pattern was particularly clear for an individual (spadefoot #2014M08) that relocated 28 times
over 63 days (Figure 2.2; details in Appendix C). Of the 28 locations recorded, one location
was used as a retreat site ten times, designating this site as a core retreat site, which was a
self-dug burrow ~ 6 cm in diameter at the edge of a well-used cattle trail. Another male
(spadefoot #2014M15), over a 17-day period, travelled ~ 740 m round-trip (Figure 2.3;
details in Appendix C). This individual was lost due to transmitter failure on July 7 but
found on July 9 in a previously used daytime retreat site. Both #2014M08 and #2014M15
repeated use daytime retreat sites were within 20 m of a breeding pond. An adult female
(spadefoot #2014F01) utilized core retreat sites between June 16 and July 30 (Figure 2.4;
Appendix C). Twenty locations were recorded during this time. An abandoned coyote den

29

Figure 2.2. Google Earth image of the movement of spadefoot #2014M08 during the 2014 tracking season. Each marker represents
each of the 28 relocations (in sequence) of the individual, beginning with R1 and ending with R28.

30

Figure 2.3. Google Earth image of the movement of spadefoot #2014M15 during the 2014 tracking season. Each marker represents
each of the 12 relocations (in sequence) of the individual, beginning with R1 and ending with R13.

31

Figure 2.4. Google Earth image of the movement of spadefoot #2014F01 during the 2014 tracking season. Each marker represents
each of the 20 relocations (in sequence) of the individual, beginning with R1 and ending with R20.

32
was utilized as a core retreat site five times between July 2 and July 23, with the spadefoot
travelling a maximum distance of ~ 40 m to and from this site. This individual was initially
captured ~ 300 m from the breeding pond. Garner (2012) found a positive correlation
between movement in relation to weather. In this study, an observation of movement
potentially related to weather occurred between June 23 and June 26. Nine out of ten
telemetered spadefoots being monitored (7 males; 2 females) exhibited extensive movements
between daytime retreat sites (max = 338.3 m; min = 36.8 m; x̅ = 154.0 m  117.0 SD). At
this time, two additional females were captured and affixed with transmitters. Historical
climate data (Government of Canada 2017) indicates June 24 experienced 12.3 mm of
precipitation, ending a 10-day dry spell, and preceded an additional 28 days without
precipitation. This was the only occurrence of this synchronized dramatic movement over a
short time period across the site.
There was no significant difference between daytime retreat sites (‘used’) and randomly
chosen sites with respect to comparison of soil moisture, aspect and slope or percent ground
cover (all Ps ≥ 0.32). These analyses suggest that, at least at the scale I measured, the adult
spadefoots were not basing selection of the daytime retreat sites on any of the parameters I
measured. Thirty out of 110 (≈ 27%) daytime retreat sites utilized by spadefoots were
created by small mammals. Detailed information on each individual telemetered is
summarized in Appendix C.
DISCUSSION
I found that spadefoots in this particular study are able to use a variety of habitats to
complete both the breeding and summer foraging components of their life history. This
species has been deemed a ‘specialist’ due to its distribution within arid to semi-arid
ecosystems and is ‘specialized’ to utilize ephemeral ponds (e.g. rapid larval development)
and dry upland habitat (e.g. moisture absorption through skin) unlike most amphibian species
(but see Garner 2012). However, within this ecosystem, they are capable of breeding and
completing metamorphosis within a range of water bodies. Further, I did not detect any
habitat characteristics particular to their upland daytime retreat sites at the microhabitat scale
examined. These observations support the notion that the species has the ability to inhabit

33
drier grassland habitats as a result of a very plastic tolerance of a fairly wide range of
conditions. These observations suggest opportunities may exist to successfully manage for
this species under specific disturbance scenarios.
Throughout the study, I observed that breeding pond type, breeding times and metamorphosis
were not synchronized across the study site. This behaviour is similar to that reported for the
Great Basin Spadefoot in California (Morey and Reznick 2004). This variability is not
uncommon in other anurans, such as the Foothill Yellow-legged Frog (Rana boylii; Wheeler
et al. 2015) and the Northern Leopard Frog (Lithobates pipiens; Randall et al. 2014).
Accelerated growth of tadpoles to reach metamorphosis prior to pond drying is common, as
previously recorded in European Spadefoot Toads (genus Pelobates) in Romania
(Cogălniceanu et al. 2013). To account for the unpredictability of spadefoot utilization of
breeding ponds in this area, species-specific and site-specific monitoring programs must be
incorporated into management plans.
Although for the aquatic parameters I studied, there was no significant difference between
breeding and non-breeding ponds, a detailed chemical analysis of breeding water bodies
might show some features that are used by spadefoots for pond selection. The permeable
skin of anurans, which permits soil moisture absorption also makes the animals susceptible to
various chemicals. For example, chloride concentration was found to influence breeding
sites of the Caucasian Salamander (Mertensiella caucasica) in the western region of Turkey
and Georgia (Sayım et al. 2009). High concentrations of copper sulfate (CuSO4 •5H2O) was
lethal for newly-hatched tadpoles of the Northern Leopard Frog, but had no effect on the
eggs of this species (Landé and Guttman 1973). A literature review of 39 papers conducted
by Albecker and McCoy (2017) revealed that increasing saltwater concentrations decreased
anuran survivorship across all life stages. Previous studies on two species of the European
spadefoot revealed variation of salinity tolerance between life stages and species (Stănescu et
al. 2017). In my study, conductivity was used as a measure of salinity in breeding ponds; it
ranged from 109 to 20525 μS/cm compared to the range of 10 to 1300 μS/cm in breeding
ponds for four other amphibian species (Boreal/Western Toad, Anaxyrus boreas; Boreal
Chorus Frogs, Pseudacris maculate; Columbia Spotted Frogs, Lithobates luteiventris; and
Barred Tiger Salamanders, Ambystoma mavortium) in the Greater Yellowstone Ecosystem

34
(Klaver et al. 2013). Because the response to chemicals in breeding ponds varies so much
between amphibian species and life stages worldwide, more research is required to determine
tolerance levels of the spadefoot in southern BC and if this impacts breeding pond selection.
The successful attraction of adult spadefoots to artificial breeding ponds within the first
spring following construction suggests there is value in creating breeding ponds in drier
environments. Creating and monitoring artificial breeding sites is considered an important
element for recovery of this species in British Columbia (BCSIRAWG 2017). There is
concern that artificial ponds may become ecological traps (COSEWIC 2007), but considering
this species is known to utilize shallow ditches and puddles for breeding, and can develop
rapidly from tadpole to metamorph in such situations, artificial ponds should prove beneficial
in areas lacking or at risk of losing breeding ponds (Pechmann et al. 2001). Artificial ponds
can be constructed quickly and with very limited equipment and funds, especially since
spadefoots don’t seem particularly demanding with respect to their design; my results suggest
that they do not have highly specific habitat requirements for breeding. Artificial ponds
should be monitored for effectiveness, built with specific species in mind and managed
appropriately.
There is little comparative information about the upland movements of adult Great Basin
Spadefoots from other parts of their range. The mean minimum and mean maximum
movements from the breeding pond (after the breeding period) to upland habitat detected in
this study are less than those found for 19 other anuran species similarly studied (see review
by Semlitsch and Bodie 2003). Garner (2012) used similar methods on spadefoots near their
extreme northern limit (approximately 110 km NW from my study site) and reported a
smaller mean maximum straight-line distance of 135.9 m  98.2 SD. Timm et al. (2014)
reported that Eastern Spadefoots (Scaphiopus holbrookii) showed a maximum mean distance
of 130 m  28.0 SD from breeding habitats. The Garner (2012) study was conducted in a
moister environment that had been impacted by decades of cattle grazing, which likely
compacted the ground. Studies on the effects of cattle grazing on amphibians have produced
inconsistent results, with no clear indication of overall effects (Pyke and Marty 2005;
McIlroy et al. 2013). In BC, cattle grazing has been reported to cause changes in vegetation,
prey species and soil compaction (Cragg 2007), that could either help or hinder amphibian

35
species, depending on management regimes. The main drivers of, or impediments to upland
movement (e.g. cattle disturbance) have yet to be determined.
Radio-telemetry revealed that during the summer, adult spadefoots in my study area travelled
through the grasslands using a ‘network’ of daytime retreat sites, with individual animals
often returning to specific sites. Vegetation percent cover comparisons show little variation
between used and available sites. These analyses suggest that adult spadefoots are not basing
their selection of these daytime retreat sites on the parameters measured in this study. A
comparison of soil moisture at the daytime retreat sites to that at neighbouring available sites
also revealed no significant difference. Small mammal burrows (e.g. gophers and mice) have
been identified as providing refuge for spadefoots (Stebbins 2003), a feature possibly more
critical when soils are compact (Sarell 2004). On my study site, small mammal burrows
were used as daytime retreat sites 27% of the time.
The use of daytime retreat sites in this study was similar to observations made by Pearson
(1955) and parallel to the Garner (2012) study. Spadefoots have the ability to return to the
precise location of a previously-used retreat. Studies on the Spotted Salamander (Ambystoma
maculatum - McGregor and Teska 1989) found olfaction to be used for orientation, while
Reshetnikov (1998) reported that the Common Tree Frog (Hyla arborea) and the Green Toad
(Bufo viridis) used a combination of olfaction and air humidity to locate breeding ponds.
Russell et al. (2005) and Sinsch (2006) suggest a combination of acoustic, magnetic,
mechanical, olfactory and visual cues are used by amphibians for orientation and navigation.
They also recommend the need for additional studies to understand these behaviours. These
studies examined orientation to breeding ponds, but not to specific daytime retreat sites
which are about 6 cm in diameter. Results of my study could not explain the strong fidelity
of some individuals to specific daytime retreat sites, and possibly hibernation sites. Further
study is required to determine the homing capability and the attraction to frequently-utilized
daytime retreat sites.
Overall, the results of this study suggest these animals may be flexible (e.g. have the ability
to adjust to spatial shifts in the arrangement of breeding ponds) to changes in their
environment and well-crafted management plans should be effective in maintaining animals

36
on modified landscapes. Species-specific and site-specific aquatic and terrestrial habitat
analyses are required to provide insight into species permanence in environments undergoing
both long-term and short-term change (Greenberg and Waldrop 2008; Smallbone et al. 2011).
In my study area, successful breeding by the animals was accomplished in a range of water
bodies over two years of study. Combined, these observations suggest that the creation of
artificial water bodies to replace those lost to anthropogenic or natural disturbance should be
effective in helping spadefoots persist on altered landscapes. In Chapter 3, I also address the
importance of appropriate microhabitat along the edges of breeding ponds. Mitigation
process should be carefully structured to ensure replacement of landscape features at a pace
matching that of disturbance loss. Such plans are impossible under processes that remove
habitat permanently (e.g. urban sprawl), but partial mitigation can at least be attempted
through the creation or re-construction of important habitat features such as water bodies and
upland habitat.
Although the above findings don’t address all current knowledge gaps, they are vital to the
conservation of this species. Additional information is needed about the importance of
hibernation sites, and the benefits of re-using specific daytime retreat sites during the course
of summer upland movements. The overall effects of landscape fragmentation and how
travelling spadefoots counter resistance are also largely unexplored. Further research is
required to fill these knowledge gaps and improve our management of these and other similar
terrestrial species.
LITERATURE CITED
Albecker, M.A., and M.W. McCoy. 2017. Adaptive responses to salinity stress across
multiple life stages in anuran amphibians. Frontiers in Zoology. 14: 40.
Alford, R.A., and S.J. Richards. 1999. Global amphibian declines: a problem in applied
ecology. Annual Review of Ecology, Evolution, and Systematics. 30: 133-165.
BC Ministry of Forests, Lands and Natural Resource Operations and Rural Development
(MFLNRORD). 2016. Biogeoclimatic Ecosystem Classification Program.
Available: https://www.for.gov.bc.ca/hre/becweb/resources/maps/index.html
(accessed Jan 14, 2016).
BC Southern Interior Reptile and Amphibian Working Group (BCSIRAWG). 2017.
Recovery plan for the Great Basin Spadefoot (Spea intermontana) in British
Columbia. Prepared for the BC Ministry of Environment. Victoria, BC. 40 pp.

37
Repr. of 1st ed., Southern Interior Reptile and Amphibian Working Group, Victoria,
BC. 40 p. (Orig. pub. 2016).
Blaustein, A.R., and J.M. Kiesecker. 2002. Complexity in conservation: lessons from the
global decline of amphibian populations. Ecology Letters. 5: 597-608.
Bolker, B.M., M.E. Brooks, C.J. Clark, S.W. Geange, J.R. Poulsen, M.H.H. Stevens, and JS.S. White. 2011. GLMMs in action: gene-by-environment interaction in total fruit
production of wild populations of Arabidopsis thaliana, revised version, part 1.
Retrieved from www.cell.com/cms/attachment/601623/4742452/mmc1.pdf (accessed
Dec 1, 2015).
Bolker, B.M., B. Gardner, M. Maunder, C.W. Berg, M. Brooks, L. Comita, E. Crone, S.
Cubaynes, T. Davies, P. de Valpine, J. Ford, O. Gimenez, M. Kéry, E.J. Kim, C.
Lennert-Cody, A. Magnusson, S. Martell, J. Nash, A. Nielsen, J. Regetz, H. Skaug,
and E. Zipkin. 2013. Strategies for fitting nonlinear ecological models in R, AD
Model Builder, and BUGS. Methods in Ecology and Evolution. 4: 501–512.
Boorse, G.C., and R.J. Denver. 2004. Endocrine mechanisms underlying plasticity in
metamorphic timing in Spadefoot Toads. Integrative and Comparative Biology.
43(5): 646-657.
Buchholz, D.R., and T.B. Hayes. 2002. Evolutionary patterns of diversity in Spadefoot
Toad metamorphosis (Anura: Pelobatidae). Copeia. 1: 180-189.
Burton, E.C., M.J. Gray, A. Chandler Schmutzer, and D.L. Miller. 2009. Differential
responses of postmetamorphic amphibians to cattle grazing in wetlands. Journal of
Wildlife Management. 73(2): 269-277.
Cogălniceanu, D., P. Székely, R. losif, D. Székely, and F. Stănescu. 2013. Life history and
conservation of Spadefoot Toads (genus Pelobates) in Romania. FrogLog. 21(5):
24-26.
Collins, J.P., and A. Storfer. 2003. Global amphibian declines: sorting the hypothesis.
Diversity and Distributions. 9: 89-98.
COSEWIC. 2007. COSEWIC assessment and update status report on the Great Basin
Spadefoot (Spea intermontana) in Canada. Committee on the Status of Endangered
Wildlife in Canada. Ottawa. vii + 34 pp.
(http://www.sararegistry.gc.ca/virtual_sara/files/cosewic/sr_spea_intermontana_e.pdf).
Cragg, J. 2007. The effects of livestock grazing on the amphibians of British Columbia. BC
Ministry of Environment. Victoria, BC.
Drayer, A.N., and S.C. Richter. 2016. Physical wetland characteristics influence amphibian
community composition differently in constructed wetlands and natural wetlands.
Ecological Engineering. 93: 166-174.
Forester, D.C., J.W. Snodgrass, K. Marsalek, and Z. Lanham. 2006. Post-breeding dispersal
and summer home range of female American Toads (Bufo americanus). Northeastern
Naturalist. 13(1): 59-72.

38
Fournier, D.A., H.J. Skaug, J. Ancheta, J. Ianelli, A. Magnusson, M. N. Maunder, A. Nielsen,
and J. Sibert. 2012. AD model builder: using automatic differentiation for statistical
inference of highly parameterized complex non-linear models. Optimization Methods
and Software. 27: 233–249.
Garner, J.L. 2012. Movement and habitat-use of the Great Basin Spadefoot (Spea
intermontana) at its northern range limit. MSc thesis, Thompson Rivers University,
Kamloops, BC, Canada. Available:
http://www.tru.ca/__shared/assets/Garner_Thesis_201233086.pdf.
Gosner, K.L. 1960. A simplified table for staging anuran embryos and larvae with notes on
identification. Herpetologica. 16(3): 183-190.
Government of Canada. 2017. Climate. Historical Climate Data. Retrieved from
http://climate.weather.gc.ca/index_e.html#access.
Greenberg, C.H., and T.A. Waldrop. 2008. Short-term response of reptiles and amphibians
to prescribed fire and mechanical fuel reduction in a southern Appalachian upland
hardwood forest. Forest Ecology and Management. 255: 2883-2893.
Hazell, D., J. Hero, D. Lindenmayer, and R. Cunningham. 2004. A comparison of
constructed and natural habitat for frog conservation in an Australian agricultural
landscape. Biological Conservation. 119: 61-71.
Hovingh, P., B. Benton, and D. Bornholdt. 1985. Aquatic parameters and life history
observations of the Great Basin Spadefoot Toad in Utah. Great Basin Naturalist.
45(1), Article 3: 22-30.
Kabacoff, R.I. 2011. R in Action: Data analysis and graphics with R. Manning Publications
Co.: Shelter Island, New York.
Klaver, R.W., C.R. Peterson, and D.A. Patla. 2013. Influence of water conductivity on
amphibian occupancy in the Greater Yellowstone Ecosystem. Western North
American Naturalist. 73(2): 184-197.
Klenner, W., R. Walton, A. Arsenault, and L. Kremsater. 2008. Dry forests in the southern
interior of British Columbia: Historic disturbances and implications for restoration
and management. Forest Ecology and Management. 256: 1711-1722.
Kline, J., and R. Packham. 2009. Great Basin Spadefoot (Spea intermontana) auditory
surveys in the Cariboo region of British Columbia, 2008. Report for the Ministry of
Environment, 100 Mile House, British Columbia, Canada.
Knutson, M.G., J.R. Sauer, D.A. Olsen, M.J. Mossman, L.M. Hemesath, and M.J. Lannoo.
1999. Effect of landscape composition and wetland fragmentation on frog and toad
abundance and species richness in Iowa and Wisconsin, U.S.A. Conservation
Biology. 13: 1437-1446.
Landé, S.P., and S.I. Guttman. 1973. The effects of copper sulfate on the growth and
mortality rate of Rana pipiens tadpoles. Herpetologica. 29(1): 22-27.
Leupin, E., D. Low, and B. Persello. 1994. Census and life history observations of the Great
Basin Spadefoot Toad (Scaphiopus intermontanus) breeding populations in the

39
Thompson Nicola regions. Report prepared for BC Ministry of Environment, Lands
and Parks. Kamloops, BC. 20 pp.
Maindonald, J.H., and W.J. Braun. 2010. Data Analysis and Graphics using R: An
Example-based Approach. Cambridge University Press. New York, New York.
Mazerolle, M.J. 2003. Detrimental effects of peat mining on amphibian abundance and
species richness in bogs. Biological Conservation. 113: 215-223.
McGregor, J.H., and W.R. Teska. 1989. Olfaction as an orientation mechanism in migrating
Ambystoma maculatum. Copeia. 1989(3): 779-781.
McIlroy, S.K., A.J. Lind, B.H. Allen-Diaz, L.M. Roche, W.E. Frost, R.L. Grasso, and K.W.
Tate. 2013. Determining the effects of cattle grazing treatments on Yosemite Toads
(Anaxyrus [=Bufo] canorus) in montane meadows. PLoS One. 8(11): e79263.
Meidinger, D., and J. Pojar. 1991. Ecosystems of British Columbia. BC Ministry of
Forests. Victoria, BC. Special Report Series 6.
Merriam-Webster. 2017. Retrieved February 4, 2017, from https://www.merriamwebster.com/dictionary/hydroperiod.
Montgomery, D.C., and E.A. Peck. 1992. Introduction to Linear Regression Analysis.
Wiley: New York.
Morey, S.R., and D.N. Reznick. 2004. The relationship between habitat permanence and
larval development in California Spadefoot Toads: field and laboratory comparisons
of developmental plasticity. Oikos. 104: 172-190.
Myers, N. 1997. The rich diversity of biodiversity issues. In: Reaka-Kudla, M.L.,
D.E.Wilson, and E.O. Wilson (Eds.). Biodiversity II: Understanding and Protecting
Our Biological Resources. Joseph Henry Press: Washington, DC.
O’Regan, S.M., W.J. Palen, and S.C. Anderson. 2014. Climate warming mediates negative
impacts of rapid pond drying for three amphibian species. Ecology. 95(4): 845-855.
Pearson, P.G. 1955. Population ecology of the Spadefoot Toad, Scaphiopus h. holbrooki
(Harlan). Ecological Monographs. 25: 233-267.
Pechmann, J.H.K., R.A. Estes, D.E. Scott, and J. Whitfield Gibbons. 2001. Amphibian
colonization and use of ponds created for trial mitigation of wetland loss. Wetlands.
21(1): 93-111.
Pyke, C.R., and J. Marty. 2005. Cattle grazing mediates climate change impacts on
ephemeral wetlands. Conservation Biology. 19(5): 1619-1625.
R Core Team. 2015. R: A language and environment for statistical computing. R
Foundation for Statistical Computing, Vienna, Austria. URL https://www.Rproject.org/.
Randall, L.A., L.D. Chalmers, A. Moehrenschlager, and A.P. Russell. 2014. Asynchronous
breeding and variable embryonic development period in the threatened Northern
Leopard Frog (Lithobates pipiens) in the Cypress Hills, Alberta, Canada:
Conservation and Management Implications. Canadian Field-Naturalist. 128: 50-56.

40
Rannap, R., A. Lõhmus, T. Tammaru, L. Briggs, W. de Vries, and F. Bibelriether. 2012.
Northern Natterjack Toads (Bufo calamita) select breeding habitats that promote
rapid development. Behaviour. 149: 737-754.
Reshetnikov, A.N. 1998. Searching for water by the Common Tree Frog (Hyla arborea)
and the Green Toad (Bufo viridis): the perception of odours or air humidity?
Advances in Amphibian Research in the Former Soviet Union. 3: 105-112.
Resources Inventory Committee. 1998. Wildlife radio-telemetry. Standards for components
of BC's biodiversity No.5. Version 2.0. Min. Environ., Lands and Parks, Resources
Inventory Br., Victoria, BC. 130 pp.
Roche, L.M., B. Allen-Diaz, D.J. Eastburn, and K.W. Tate. 2012. Cattle grazing and
Yosemite Toad (Bufo canorus Camp) breeding habitat in Sierra Nevada Meadows.
Rangeland Ecology and Management. 65(1): 56-65.
Ruibal, R., L. Tevis Jr., and V. Roig. 1969. The terrestrial ecology of the Spadefoot Toad
Scaphiopus hammondii. Copeia. 1969(3): 571-584.
Russell, A.P., A.M. Bauer, and M.K. Johnson. 2005. Migration in amphibians and reptiles:
an overview of patterns and orientation mechanisms in relation to life history
strategies. In: Elewa, A.M.T. (Ed.), Migration in Organisms. Springer, Berlin, pp.
151–203.
Sarell, M. 2004. Great Basin Spadefoot, Spea intermontana. In accounts and measures for
managing identified wildlife – Accounts V. 2004 (7 pp.). Ministry of Water, Land
and Air Protection. Victoria, BC, Canada.
Sayım, F., E. Başkale, D. Tarkhnishvili, and U. Kaya. 2009. Some water chemistry
parameters of breeding habitats of the Caucasian Salamander, Mertensiella caucasica
in the Western Lesser Caucasus. Ecology. 332(5): 464-469.
Semlitsch, R.D., and J.R. Bodie. 1998. Are small, isolated wetlands expendable?
Conservation Biology. 12(5): 1129-1133.
Semlitsch, R.D., and J.R. Bodie. 2003. Biological criteria for buffer zones around wetlands
and riparian habitats for amphibians and reptiles. Conservation Biology. 17(5):
1219-1228.
Semlitsch, R.D., W.E. Peterman, T.L. Anderson, D.L. Drake, and B.H. Ousterhout. 2015.
Intermediate pond sizes contain the highest density, richness, and diversity of pondbreeding amphibians. PLoS One. 10(4): e0123055.
Sinsch, U. 2006. Orientation and navigation in amphibia. Marine and Freshwater
Behaviour and Physiology. 39(1): 65-71.
Skaug, H., D. Fournier, B. Bolker, A. Magnusson, and A. Nielsen. 2015. Generalized linear
mixed models using AD model builder. R package version 0.8.3.3.
Smallbone, L.T., G.W. Luck, and S. Wassens. 2011. Anuran species in urban landscapes:
Relationships with biophysical, built environment and socio-economic factors.
Landscape and Urban Planning. 101: 43-51.

41
Stănescu, F., D. Székely, P. Székely, S. Topliceanu, and D. Cogălniceanu. 2017. The impact
of salinity on early development stages in two sympatric Spadefoot Toads and
implications for amphibian conservation in coastal areas. Hydrobiologia. 792: 357–
366.
Stebbins, R.C. 2003. A field guide to western reptiles and amphibians. Third edition.
Houghton Mifflin Company. Boston, Massachusetts. 533 pp.
Stuart, S.N., J.S. Chanson, N.A. Cox, B.E. Young, A.S.L. Rodrigues, D.L. Fischman, and
R.W. Waller. 2004. Status and trends of amphibian declines and extinctions
worldwide. Science. 306: 1783-1786.
Timm, B.C., K. McGarigal, and R.P. Cook. 2014. Upland movement patterns and habitat
selection of adult Eastern Spadefoots (Scaphiopus holbrookii) at Cape Cod National
Seashore. Journal of Herpetology. 48(1): 84-97.
Warren, S.D., and R. Büttner. 2008. Relationship of endangered amphibians to landscape
disturbance. Journal of Wildlife Management. 72(3): 738-744.
Wheeler, C.A., J.B. Bettaso, D.T. Ashton, and H.H. Welsh Jr. 2015. Effects of water
temperature on breeding phenology, growth, and metamorphosis of Foothill Yellowlegged Frogs (Rana boylii): a case study of the regulated mainstem and unregulated
tributaries of California’s Trinity River. River Research and Applications. 31: 12761286.
Wikeem, B., and S. Wikeem. 2004. The grasslands of British Columbia. Grasslands
Conservation Council of British Columbia. Kamloops, BC. xvii + 479 pp.
Wright, A.H., and A.A. Wright. 1949. Handbook of Frogs and Toads of the United States
and Canada. Comstock Publishing Company, Inc: Ithaca, New York.
Zuur, A.F., E.N. Ieno, and C.S. Elphick. 2010. A protocol for data exploration to avoid
common statistical problems. Methods in Ecology and Evolution. 1: 3-14.
Zuur, A.F., J.M. Hilbe, and E.N. Ieno. 2012. Zero Inflated Models and Generalized Linear
Mixed Models with R. Highland Statistics Ltd: Newburgh, UK.

42
CHAPTER 3. MICROHABITAT SELECTION BY NEWLY-METAMORPHOSED GREAT BASIN
SPADEFOOTS (SPEA INTERMONTANA): A MICROCOSM STUDY
INTRODUCTION
Habitat selection by juvenile animals is poorly understood, particularly for those species
without any level of parental care or association. In these cases, habitat associations and
preferences demonstrated by the young animals may be critical to immediate survival and,
ultimately, successful recruitment into the population (Patrick et al. 2008). Amphibians
provide striking examples of this situation: individuals transforming from aquatic larvae to
terrestrial animals will abruptly face a different suite of environmental conditions, and the
ability to find appropriate habitat may be imperative to survival (Rittenhouse et al. 2008).
Understanding habitat selection during this stage of development is important to designing
conservation strategies that do not focus solely on adult habitat needs (Biek et al. 2002;
Vonesh and De la Cruz 2002).
North American spadefoots (genera Scaphiopus and Spea) are terrestrial, burrowing
amphibians associated with arid or semi-arid habitats. They rely on two distinct habitats to
survive: (1) water bodies for breeding and tadpole development and (2) terrestrial habitat for
feeding, aestivation and hibernation (Pearson 1955). Habitat studies on these species have
focused largely on adult breeding sites (e.g. Nystrom et al. 2002; Morey and Reznick 2004).
As a result, very little is known about the habitat preference of newly-metamorphosed
spadefoots ('metamorphs'), owing in part to their small size and cryptic nature. As postmetamorphic juveniles do not remain in the water, they are likely vulnerable to desiccation
and predation upon emergence, so habitat available near the water’s edge will likely play a
key role in enabling some proportion of the animals to survive the critical early stages of
terrestrial life (Rothermel and Semlitsch 2006; Roznick and Johnson 2009). Heinen (1993)
and Baughman and Todd (2007) conducted lab experiments on recently metamorphosed
anurans and concluded that vegetative cover was chosen over bare ground, and that cover
was significant in providing protection from predators; however, neither of these studies
included soil moisture as a factor. Jansen et al. (2001) concluded that Eastern Spadefoot
metamorphs (Scaphiopus holbrookii holbrookii) preferred moist substrate over dry. Grover
(1998) analyzed cover and soil moisture and found both to be significant in predicting

43
abundance of both juvenile and adult terrestrial salamanders (Plethodon cinereus and
Plethodon glutinosus) in a Virginia forest. Further studies are clearly required to explore the
relationship between cover and moisture in determining habitat selection during the critical
emergence stage of amphibians. Such work can guide the artificial creation of breeding
ponds or the retention of key microhabitats during reclamation or other habitat management.
The Great Basin Spadefoot (Spea intermontana) ranges further north than any other
spadefoot in North America, occupying the semi-arid grasslands of British Columbia (BC)
(COSEWIC 2007; BCSIRAWG 2017). This ecosystem makes up less than 1% of the
province (Wikeem and Wikeem 2004). Summer temperatures in these grasslands are
reasonably warm during June and July, when metamorphic spadefoots tend to emerge from
water bodies. The ecosystem has been affected over many decades by various forms of both
anthropogenic and natural disturbance, substantially altering the habitat. This includes a
dramatic decrease in grassland ephemeral ponds (Coelho 2015) that are used by the
spadefoot. Extensive grazing and water use by cattle has also degraded the habitat around
many of the remaining ponds (Jones et al. 2011; Teuber et al. 2013).
Given the small size of metamorphic spadefoots (see Methods), I hypothesized that newlymetamorphosed animals would be highly susceptible to the effects of desiccation,
particularly in the relatively warm, dry climate in this region. In this study, I report on a
microcosm experiment used to investigate microhabitat preferences of newlymetamorphosed Great Basin Spadefoots. The ultimate purpose of this work was to provide
information that would help shape emerging guidelines for the rehabilitation, protection and
creation of spadefoot habitat on the BC interior landscape. My work on a suite of water
bodies (see Chapter 2) suggests that these animals are able to successfully breed under a wide
range of physical conditions. This suggests that appropriate shoreline habitat that facilitates
the transition of offspring to terrestrial habitat may play a more important role in maintaining
the species on the landscape.

44
METHODS
Study Area
This study took place throughout August 2014 in the semi-arid grasslands in the Thompson
River valley, approximately 10 km west of Kamloops, BC, Canada (50°41’38” N, 120°32’7”
W). Typically, summers here are warm and dry (Chilton 1981) with normal average
temperatures during June and July ranging from 11.6C to 25.1C and14.2C and 28.9C
respectively (Government of Canada 2017). Ephemeral alkaline ponds and wetlands are
sporadic on the landscape, a feature typical of this zone (Meidinger and Pojar 1991). Due to
current and historical cattle grazing, Big Sagebrush (Artemisia tridentata), Cheatgrass
(Bromus tectorum) and Knapweed (Centaurea sp.) dominate upland sites. The elevation of
the study area is ≈ 643 meters above sea level (MSL).
To minimize artificial effects, I conducted this work outdoors in the field, in close proximity
to a known spadefoot breeding site (Figure 3.1), where tadpole development was occurring
naturally (see Chapter 1). This location provided a protected ‘semi-natural’ environment,
open to fluctuating ambient temperature and humidity, and the diurnal cycle.
Microcosm Construction
I established a total of four enclosures (i.e. microcosms) using plastic arenas (children's
wading pools) approximately 1.2 m diameter with a wall height of approximate 20 cm. Each
microcosm was divided into four quadrants with one central starting platform (Figure 3.2).
Across these quadrants I established four different microhabitat types: dry-bare, dry-cover,
moist-bare and moist-cover. Each arena was filled to a depth of 5 cm (volume = 0.06 m3)
with a 1:1 mixture of sand and silt. Two litres of deionized water was applied to the half of
the microcosm containing moist habitat. Plastic dividers were used to separate the moist soil
in these quadrants from the dry treatments, but care was taken to ensure that there were no
physical surface barriers for the metamorphs between the moist and dry halves. A fresh soil
mixture was used in each trial to remove any chemical traces from the soil, similar to the
precautions taken by Baughman and Todd (2007). The soil mixture was sifted prior to being
placed into the arena to ensure all large particles were removed. Light raking ensured an
even surface prior to commencement of the trial. Pine cover boards (~ 15 cm x 30 cm) were

45

Figure 3.1. Location of metamorph microhabitat selection study in the semi-arid grasslands in the Thompson River valley,
approximately 10 km west of Kamloops, BC, Canada. Photo by author.

46
placed in two of the four quadrants to create ‘covered’ habitats. The boards were raised ~ 2.5
cm above the soil with wooden sticks. Stones were positioned on top of the cover boards to
ensure stability. During the trials, each arena was covered with a screen, fine enough to
prevent predators from entering the pools and to prevent metamorphs from escaping, but
coarse enough to prevent shading.
Although the four arenas were laid out in an identical fashion, each one was sequentially
rotated 0, 90, 180 and 270 degrees at the start of each trial to avoid bias in directional
orientation. Following Heinen (1993) and Baughman and Todd (2007), the rotation of the
arenas also controlled for other possible stimuli in the surrounding environment (e.g.
presence of a wetland, direction of the sun). To collect comparative temperatures, two
Maxim Integrated iButton Thermochron ® temperature data loggers (model DS1921G) were
buried 2.5 cm along the outside edge of each quadrant. These loggers recorded temperatures
every hour over the 36-hour trial period. Data from the loggers allowed me to verify that
temperatures across the four treatment quadrants did not vary significantly and therefore
exert an effect on the metamorphs.
Metamorph Introduction
During this study, metamorphosis of larvae occurred between 7 to 13 weeks of age; size at
emergence from the water was 18.7 mm SVL  2.8 SD (n= 130) and 0.66 g  0.33 SD
(n=130). I fenced natal ponds when tadpoles neared the later stages of metamorphosis in
order to capture the animals immediately upon emergence from the water. Metamorphs were
hand captured inside these fences shortly before each series of trials was about to begin (45
minutes or less). I only selected individuals that had completely absorbed their tail into their
body (i.e. Gosner stage 46; Gosner 1960) and were physically able to move onto land. The
animals were transported to the arenas in small plastic containers. Once there, individuals
were weighed (g) on a portable electronic scale (Salter 1250BKEF) and permanently marked
on the right, hind foot with fluorescent yellow Visible Implant Elastomer (VIE) (Northwest
Marine Technology, Inc.). The VIE marker was utilized to ensure individuals participated in
only one trial and were not later recaptured and retested.

47

Dry-Bare

Moist-Cover

iButton
Locations

Cover
Inner Ring

Board

Board
Central
Platform

Cover
Board

Dry-Cover

Moist-Bare

Figure 3.2. Schematic of artificial enclosure (i.e. microcosm) divided into four habitat
types (e.g. dry-bare, dry-cover, moist-bare, moist-cover) to investigate microhabitat
selection by newly-metamorphosed Great Basin Spadefoots.

48
Each trial consisted of ten newly-metamorphosed spadefoots being introduced into the centre
of each of the four microcosm arenas. Once each trial was complete, the individuals were
removed from the arenas and immediately released back into their original natal pond.
Microhabitat Analysis
I conducted a total of 13 trials (i.e. one set of ten spadefoots in an enclosure = one trial), run
in four batches. Of 16 possible trials, one trial was omitted due to metamorphs escaping the
enclosure and two were omitted due to lack of metamorphs available. Each batch took place
over two nights, spanning 36 hours from start to finish. Prior to initial release, as per
Baughman and Todd (2007), the animals were placed on the central platform and covered
within the inner ring for ten minutes, allowing time for the individuals to partially adjust to
their surroundings. The inner ring and cover was then removed and the animals were
visually monitored until each had left the central platform and entered one of the four habitat
quadrants. The location of each metamorph, according to quadrant association, was recorded
at three time periods: At release, 12 hours and 36 hours. ‘At release’ was defined as the
exact moment each individual left the inner ring and entered a quadrant. My rationale for the
latter time periods was to provide ample time (including two night periods) for the animals to
explore, adjust and choose a position within their new surroundings.
To determine locations of the metamorphs in the arenas at the 12 hour and 36 hour points, the
screen was removed gently to prevent disturbance and a visual inspection was completed.
When necessary, cover boards were briefly removed and animals were counted. Once all ten
animals were accounted for in each arena, cover boards and screens were gently repositioned.
Extreme care was taken to acquire individual locations as quickly as possible with no
disturbance to either the animal or the arena. Metamorphs were gently unearthed if no
sighting could be made, but evidence of a burrow existed; they were then promptly covered
with soil.
Statistical Analysis
Statistical analysis was performed using R 3.2.5 (R Core Team , 2015). Prior to conducting
analysis, the categorical variables (e.g. direction, cover type) were appropriately designated

49
using the ordered (for ordered categorical (ordinal) variables) and factor (for categorical
(nominal) variables) functions (Bolker et al. 2011; Kabacoff 2011).
I tested for correlation among my predictor variables (i.e. direction, cover type, soil
temperature) by calculating a generalized variance inflation factor (GVIF) following the
procedure outlined by Zuur et al. (2012) and Fox and Monette (1992). The GVIF measures
how much the variance of a predictor is increased because of linear dependence with other
predictors. As recommended by Zuur et al. (2010), I used a GVIF value of three as the preselected threshold (indicating no collinearity), versus the higher (and more flexible) value of
ten as used by Montgomery and Peck (1992).
I tested whether the metamorphs exhibited equal preference for the four habitat types and
directionality in each arena by conducting Fisher’s exact tests using the lattice package in R
(Sarkar 2008). The results indicated whether data within each batch of trials could be pooled
for a robust analysis of metamorph microhabitat preference.
To effectively predict metamorph microhabitat selection, I analyzed the zero-inflated,
grouped, non-normal count data with mixed effects using a zero-inflated Poisson (ZIP)
generalized linear mixed model (GLMM; Bolker et al. 2013). The ZIP model accounted for
the high number of true zeros in the count data (38.5%) (Lambert 1992; Zuur et al. 2009).
The glmmADMB package (Fournier et al. 2012; Skaug et al. 2015) was used with a loglink
function, to determine whether there was a relationship between the number of observations
(i.e. number of metamorphs) within each quadrant for each trial and time period, and the
three explanatory variables ‘direction’, ‘cover’ and ‘soil temperature’. The random effects
were attributed to our grouping (i.e. nesting) variables, ‘time’ and ‘trial’. I completed the
analysis by checking the data set for overdispersion (Crawley 2002) following the process of
Zuur et al (2012).
RESULTS
In total, I collected data from thirteen arena trials (in four batches) and 130 animals. The
mean air temperature (C) during trials one through four ranged from 25.4  0.9 SD and 20.9
 2.8 SD. Total precipitation (mm) for trial 1, 2, 3, and 4 was 0.0, 4.4, 0.7, and 0.0

50
respectively. At release (immediately after the ten minute acclimation period in the center of
the arenas), the metamorphs dispersed into all four habitat types (e.g. dry-bare, dry-cover,
moist-bare, moist-cover) showing no preference for a particular habitat type. After 12 hours,
the metamorphs were beginning to show a preference for moist-cover. After the 36 hour
time period, there was a clear indication that metamorphs were selecting for moist-cover
habitat (Figure 3.3).
Data on microhabitat choice from the 13 trials could be pooled, as per Fisher’s exact tests, for
both cover type (P = 0.07) and direction (P = 0.07). The GVIF values for direction, cover
and soil temperature were 1.02, 1.11 and 1.09 respectively. Metamorphs (n=130) were
frequently found aggregated in the different quadrants, which in turn resulted in the majority
of quadrant counts containing zero animals.
The resulting analysis of the pooled data indicated that metamorph habitat choice was
dependent on cover type (P = 0.04) but independent of the direction of the arena (P = 0.62).
After 36 hours, 74% of metamorphs were located in moist-cover habitat rather than dry-bare,
dry-cover or moist-bare habitats. Metamorphs chose quadrants based on the type of cover
represented regardless of the direction the arena was rotated.
The ZIP GLMM indicated that the metamorphs strongly preferred moist-cover habitat type (z
= 6.24, P < 0.001, n=130). All other habitat types, direction and soil temperature were not
significant (all other Ps > 0.19).
DISCUSSION
Previous laboratory experiments have shown that recently-metamorphosed anurans prefer
some type of vegetative cover over bare ground (not including moisture as a factor) (Heinen
1993; Baughman and Todd 2007), but this study demonstrates that newly-metamorphosed
Great Basin Spadefoots prefer moist microhabitats with cover. Although this response is
intuitive for a small metamorphic amphibian entering a terrestrial environment, this is the
first clear demonstration for such a preference within this life-history stage of this species.
While this work was performed in an arena, it seems likely that metamorphs emerging from
water bodies would exhibit the same behaviour in a natural setting. Observations in the field

51

10
8

At Release

6
4
2
0

Observations

12
10

12 Hours

8
6
4
2
0

12
10

36 Hours

8
6
4
2
0
DB

DC

MB

MC

Cover Type
Figure 3.3. Microhabitat selection of metamorphic Great Basin Spadefoots within
microcosm arenas (n=130). The four available habitat types in each arena: dry-bare
(DB), dry-cover (DC), moist-bare (MB) and moist-cover (MC), are displayed on the
ordinate. The locations of the metamorphs were determined over three time periods:
At Release, 12 hours and 36 hours. After 36 hours, there is a clear indication that
moist-cover habitat is preferred over other habitat types.

52
support this theory: I detected metamorphs taking refuge in moist soil under plywood
adjacent to an evaporating pond, and within moist fissures at the edges of other ponds. My
results parallel a field study conducted by Weintaub (1980), who found recentlymetamorphosed New Mexico Spadefoot (Scaphiopus multiplicatus) individuals under
boards, in shallow retreats, cow dung or fissures caused by drying of pond edges during the
daytime. Baughman and Todd (2007) also found similar results for newly-metamorphosed
Eastern Spadefoot (Scaphiopus holbrookii) in laboratory experiments in South Carolina.
Walston and Mullin (2008) found that juvenile amphibians in Illinois, including the Smallmouthed Salamander (Ambystoma texanum), American Toad (Bufo americanus), and Wood
Frog (Rana sylvatica), exhibited non-random orientation moving in the direction of forested
habitat versus disturbed open areas with little canopy cover. Combined, these findings
suggest that many, if not most, species of amphibians transitioning from an aquatic juvenile
stage to one that uses drier upland habitat would preferentially seek out moist habitat with
cover.
Garner (2012) studied upland habitat selection of Great Basin Spadefoots near their northern
limit (about 110 km NW of the present study). Using telemetered adult animals, she found
selection for daytime retreat sites that contained a relatively high proportion of bare ground
(see Chapter 2). Superficially, this seems to suggest a very different pattern of habitat
selection between life-history stages in this species (i.e. habitat preferences might change or
shift as the animal’s age). However, her study site was situated within a cooler, moister
ecosystem, suggesting the animals may have been more limited by heat and thus selected for
bare (warmer) ground to bury into. Further, the smaller surface area: volume ratio of the
adult animals may enable them to remain buried underground for longer periods of time,
retaining and/or absorbing soil moisture through their permeable skin (Ruibal et al. 1969).
Metamorphs, being much smaller in size, likely have a lower tolerance for dry conditions,
and therefore have different habitat requirements. This study did not examine all factors that
could influence the terrestrial habitat choice of newly-metamorphosed spadefoots, but it did
determine that, given the conditions provided, moist habitat with cover is preferred directly
following metamorphosis.

53
This work has important implications for the management of this species, particularly in drier
environments. Given the results of this and similar studies, I recommend retaining or
establishing breeding water bodies with natural or artificial cover material (e.g. plants, coarse
woody debris, cover boards) situated along the immediate perimeter (within 0.3 m) of the
pond edge to provide shelter and moisture. Such conditions should increase the quality of
suitable terrestrial microhabitats for vulnerable, newly-metamorphosed spadefoots. The
presence of these features may be extended over larger areas surrounding water bodies to
provide additional resources for the animals as they disperse further from the breeding pond.
Breeding ponds also should be protected from sources of disturbance (e.g. cattle,
development). Livestock use of water bodies and riparian areas can leave shorelines and
neighbouring habitat devoid of vegetation and other cover.
Our knowledge of upland habitat requirements for metamorphs is significantly constrained
by technology, including telemetry. Knowledge of the dispersal phase for these animals is
particularly limited: the distance travelled from the breeding pond upon metamorphosis, day
retreat site locations and types, and hibernation locations are virtually unknown for juvenile
animals. Inventive methods will need to be employed to collect these sorts of data; for
example, Popescu and Hunter (2011) tracked movement and recorded habitat preferences of
newly-metamorphosed Wood Frogs using ‘runway’ enclosures with pitfall traps and tracking
stations. Similar methods may be needed to further our understanding of habitat
requirements for spadefoots across all life-history stages.
LITERATURE CITED
Baughman, B. and B.D. Todd. 2007. Role of substrate cues in habitat selection by recently
metamorphosed Bufo terrestris and Scaphiopus holbrookii. Journal of Herpetology.
41(1): 154-157.
BC Southern Interior Reptile and Amphibian Working Group (BCSIRAWG). 2017.
Recovery plan for the Great Basin Spadefoot (Spea intermontana) in British
Columbia. Prepared for the BC Ministry of Environment. Victoria, BC. 40 pp.
Repr. of 1st ed., Southern Interior Reptile and Amphibian Working Group, Victoria,
BC. 40 p. (Orig. pub. 2016).
Biek, R., W.C. Funk, B.A. Maxell, and L. Scott Mills. 2002. What is missing in amphibian
decline research: insights from ecological sensitivity analysis. Conservation Biology.
16(3): 728-734.

54
Bolker, B.M., M.E. Brooks, C.J. Clark, S.W. Geange, J.R. Poulsen, M.H.H. Stevens, and JS.S. White. 2011. GLMMs in action: gene-by-environment interaction in total fruit
production of wild populations of Arabidopsis thaliana, revised version, part 1.
Retrieved from www.cell.com/cms/attachment/601623/4742452/mmc1.pdf (accessed
Dec 1, 2015).
Bolker, B.M., B. Gardner, M. Maunder, C.W. Berg, M. Brooks, L. Comita, E. Crone, S.
Cubaynes, T. Davies, P. de Valpine, J. Ford, O. Gimenez, M. Kéry, E.J. Kim, C.
Lennert-Cody, A. Magnusson, S. Martell, J. Nash, A. Nielsen, J. Regetz, H. Skaug,
and E. Zipkin. 2013. Strategies for fitting nonlinear ecological models in R, AD
Model Builder, and BUGS. Methods in Ecology and Evolution. 4: 501–512.
Chilton, R. H. 1981. A summary of climate regimes of British Columbia. BC Ministry of
Environment. Victoria, BC.
Coelho, A.J.A. 2015. Assessing climate change induced declines in ponds in British
Columbia’s semi-arid grasslands. MSc thesis, Thompson Rivers University,
Kamloops, BC, Canada. Available:
http://www.tru.ca/__shared/assets/Coelho_thesis34900.pdf.
COSEWIC. 2007. COSEWIC assessment and update status report on the Great Basin
Spadefoot (Spea intermontana) in Canada. Committee on the Status of Endangered
Wildlife in Canada. Ottawa. vii + 34 pp.
(http://www.sararegistry.gc.ca/virtual_sara/files/cosewic/sr_spea_intermontana_e.pdf).
Crawley, M.J. 2002. Statistical computing: An introduction to data analysis using S-Plus.
Wiley: New York.
Fournier, D.A., H.J. Skaug, J. Ancheta, J. Ianelli, A. Magnusson, M. N. Maunder, A. Nielsen
and J. Sibert. 2012. AD model builder: using automatic differentiation for statistical
inference of highly parameterized complex non-linear models. Optimization Methods
and Software. 27: 233–249.
Fox, J. and G. Monette. 1992. Generalized collinearity diagnostics. Journal of the
American Statistical Association. 87(417): 178-183.
Garner, J.L. 2012. Movement and habitat-use of the Great Basin Spadefoot (Spea
intermontana) at its northern range limit. MSc thesis, Thompson Rivers University,
Kamloops, BC, Canada. Available:
http://www.tru.ca/__shared/assets/Garner_Thesis_201233086.pdf.
Gosner, K.L. 1960. A simplified table for staging anuran embryos and larvae with notes on
identification. Herpetologica. 16(3): 183-190.
Government of Canada. 2017. Climate. Historical Climate Data. Retrieved from
http://climate.weather.gc.ca/index_e.html#access.
Grover, M.C. 1998. Influence of cover and moisture on abundances of the Terrestrial
Salamanders Plethodon cinereus and Plethodon glutinosus. Journal of Herpetology.
32(4): 489-497.

55
Heinen, J.T. 1993. Substrate choice and predation risk in newly metamorphosed American
Toads Bufo americanus: An experimental analysis. American Midland Naturalist.
130(1): 184-192.
Jansen, K.P., A.P. Summers, and P.R. Delis. 2001. Spadefoot Toads (Scaphiopus holbrookii
holbrookii) in an urban landscape: effects of nonnatural substrates on burrowing in
adults and juveniles. Society for the Study of Amphibians and Reptiles. 35(1): 141145.
Jones, W.M., L.H. Fraser, and P. Jefferson Curtis. 2011. Plant community functional shifts
in response to livestock grazing in intermountain depressional wetlands in British
Columbia, Canada. Biological Conservation. 144(1): 511-517.
Kabacoff, R.I. 2011. R in Action: Data analysis and graphics with R. Manning
Publications Co.: Shelter Island, New York.
Lambert, D. 1992. Zero-inflated Poisson regression, with an application to defects in
manufacturing. Technometrics. 34: 1-14.
Meidinger, D., and J. Pojar. 1991. Ecosystems of British Columbia. BC Ministry of
Forests. Victoria, BC. Special Report Series 6.
Montgomery, D.C., and E.A. Peck. 1992. Introduction to Linear Regression Analysis.
Wiley: New York.
Morey, S.R., and D.N. Reznick. 2004. The relationship between habitat permanence and
larval development in California Spadefoot Toads: field and laboratory comparisons
of development plasticity. Oikos. 104: 172-190.
Nyström, P., L. Birkedal, C. Dahlberg, and C. Brönmark. 2002. The declining Spadefoot
Toad Pelobates fuscus: calling site choice and conservation. Ecography. 25: 488498.
Patrick, D.A., E.B. Harper, M.L. Hunter Jr., and A.J.K. Calhoun. 2008. Terrestrial habitat
selection and strong density-dependent mortality in recently metamorphosed
amphibians. Ecology. 89(8): 2563-2574.
Pearson, P.G. 1955. Population ecology of the Spadefoot Toad, Scaphiopus h. holbrooki
(Harlan). Ecological Monographs. 25(3): 233-267.
Popescu, V.D., and M.L. Hunter Jr. 2011. Clear-cutting affects habitat connectivity for a
forest amphibian by decreasing permeability to juvenile movements. Ecological
Applications. 21(4): 1283-1295.
R Core Team. 2015. R: A language and environment for statistical computing. R
Foundation for Statistical Computing, Vienna, Austria. URL https://www.Rproject.org/.
Rittenhouse, T.A.G., E.B. Harper, L.R. Rehard, and R.D. Semlitsch. 2008. The role of
microhabitats in the desiccation and survival of anurans in recently harvested oakhickory forest. Copeia. 4: 807-814.
Rothermel, B.B., and R.D. Semlitsch. 2006. Consequences of forest fragmentation for

56
juvenile survival in Spotted (Ambystoma maculatum) and Marbled (Ambystoma
opacum) Salamanders. Canadian Journal of Zoology. 84: 797-807.
Roznik, E.A., and S.A. Johnson. 2009. Burrow use and survival of newly metamorphosed
Gopher Frogs (Rana capito). Journal of Herpetology. 43(3): 431-437.
Ruibal, R., L. Tevis Jr., and V. Roig. 1969. The terrestrial ecology of the Spadefoot Toad
Scaphipus hammondii. Copeia. 1969(3): 571-584.
Sarkar, D. 2008. Lattice: Multivariate Data Visualization with R. Springer, New York.
ISBN 978-0-387-75968-5.
Skaug, H., D. Fournier, B. Bolker, A. Magnusson and A. Nielsen. 2015. Generalized linear
mixed models using AD model builder. R package version 0.8.3.3.
Teuber, L.M., N. Hölzel, and L.H. Fraser. 2013. Livestock grazing in intermountain
depressional wetlands – Effects on plant strategies, soil characteristics and biomass.
Agriculture, Ecosystems and Environment. 175: 21-28.
Vonesh, J.R., and O. De la Cruz. 2002. Complex life cycles and density dependence:
assessing the contribution of egg mortality to amphibian declines. Oecologia. 133:
325-333.
Walston, L.J., and S.J. Mullin. 2008. Variation in amount of surrounding forest habitat
influences the initial orientation of juvenile amphibians emigrating from breeding
ponds. Canadian Journal of Zoology. 86: 141-146.
Weintraub, J.D. 1980. Selection of daytime retreats by recently metamorphosed Scaphiopus
multiplicatus. Journal of Herpetology. 14: 83–84.
Wikeem, B., and S. Wikeem. 2004. The grasslands of British Columbia. Grasslands
Conservation Council of British Columbia. Kamloops, BC. xvii + 479 pp.
Zuur, A.F., E.N. Ieno, N.J. Walker, A.A. Saveliev, and G.M. Smith. 2009. Mixed Effects
Models and Extensions in Ecology with R. Springer: New York.
Zuur, A.F., E.N. Ieno, and C.S. Elphick. 2010. A protocol for data exploration to avoid
common statistical problems. Methods in Ecology and Evolution. 1: 3-14.
Zuur, A.F., J.M. Hilbe, and E.N. Ieno. 2012. Zero Inflated Models and Generalized Linear
Mixed Models with R. Highland Statistics Ltd: Newburgh, UK.

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CHAPTER 4. CONCLUSION
SUMMARY
The purpose of this study was to improve our understanding of the habitat associations of the
Great Basin Spadefoot (Spea intermontana) within disturbed arid grasslands. The goal was
thus to provide recommendations for action that will maintain spadefoot populations in such
environments, and to assist in the development of spadefoot conservation management plans
and policies such as that created by the author for the New Gold - New Afton Mine
(Appendix D). Like most amphibians, the biphasic life cycle of the spadefoot requires a
parallel analysis of two very distinct habitats that are each necessary for the species’ survival
(Pearson 1955; Melcher 2015). I investigated a variety of attributes of the aquatic and
terrestrial habitats available to the species at the New Gold - New Afton Mine, and also
conducted a novel microcosm study investigating metamorph habitat preferences. Prior to
my study, little was known regarding adult habitat preferences within the dry, southern
interior of British Columbia (BC), and even less was known about these preferences for
animals in the metamorphic stage. This study provides a critical link between adult and
metamorph habitat requirements. My main questions were:
1.

Do spadefoots use specific types of breeding ponds?

2.

Will adult spadefoots colonize artificial ponds at this site?

3.

Once adult spadefoots leave breeding ponds, are there specific features they
search for in daytime retreat sites? Are there movement patterns that can help
predict habitat use?

4.

What are the habitat preferences (at the micro-scale) of newly-metamorphosed
spadefoots who rely on both aquatic and terrestrial habitats?

Notable results from my research are:
•

Adult spadefoots in this area exhibited flexibility to a variety of aquatic and
terrestrial conditions.

•

Adult spadefoots were variable in their upland movement patterns.

58
•

Artificial ponds were quickly colonized with successful emergence of
metamorphs.

•

Appropriate microhabitat (i.e. cover) along edges of breeding ponds is
significant for newly-metamorphic spadefoots as they disperse into upland
habitat.

My results indicated that spadefoots in this area did not select specific aquatic or terrestrial
habitat features, at least within the timeframe and range occurring on my study site. This
suggests the animals can utilize a variety of habitats on this arid landscape. Adult spadefoots
were quick to locate and breed in artificial ponds, resulting in successful metamorphosis of
spadefoots within the first season of construction. Upon exiting the ponds, newlymetamorphosed spadefoots selected daytime retreat sites that provided moisture and cover.
Adult spadefoot movement patterns (e.g. distance travelled from breeding ponds, use of core
daytime retreat sites) were similar to the Garner (2012) study conducted in their
northernmost part of their range in the BC Cariboo region.
MANAGEMENT IMPLICATIONS
These results on the life-stage requirements of the spadefoot, provide a valuable resource for
generating plans for this species in this region. This study addresses knowledge gaps in BC
regarding movement and habitat use of spadefoots, and can thus help provide guidelines for
the creation of artificial spadefoot habitat (BCSIRAWG 2017). For the most part, BC
recovery objectives align with my results, but lack acknowledgement of newly-metamorphic
spadefoot requirements.
It is imperative that we acknowledge and understand the significance of each life stage and
the desirable landscape features of a species when creating effective management plans.
Developing a management plan for an elusive, small nocturnal species at risk is challenging.
However, collecting basic information on the natural history of these animals often enables
managers to create and/or refine conservation strategies. The results of my research
emphasize that management plans must be site and species specific to account for aquatic
and terrestrial environments, and variations in life stage requirements. My research builds
upon that of the Garner (2012) study (conducted at the extreme northern limit of the species,

59
approximately 110 km NW of my site). As mentioned earlier, the Garner study was
conducted in a considerably wetter and cooler habitat, so combined the two studies, provide
valuable insight into the habitat requirements of the spadefoot in BC.
Aquatic Habitat Management
Artificial ponds, like the ones I constructed, can be used as management tools, especially in
disturbed areas where there is little or no difference between the breeding and non-breeding
ponds I examined. It is a staggering reality that natural breeding ponds are quickly declining,
and the supplementation of breeding ponds is now a necessity. Coelho (2015) reported a
63% decline in the number of ponds in BC’s southern interior grasslands from 1992-2012.
Concerns that artificial ponds can be ecological sinks are valid (i.e. unsuitable breeding
habitat (Sarell 2004; COSEWIC 2007)), but studies have shown that artificial ponds can be
beneficial (Pechmann et al. 2001). I believe these ponds can be built in areas thought to be
void of spadefoots (where they were previously observed) or provide ‘stepping stones’ from
a pond at risk of natural or man-caused destruction to a healthy pond. Breeding times and
tadpole development were not synchronized across my site, leading to my recommendations
that both artificial and natural breeding ponds be maintained and protected from disturbance
from the onset of the breeding season (typically April) through to complete emergence of
metamorphs (exact timing is pond-dependent).
Terrestrial Habitat Management
In my study, spadefoots travelled approximately 500 m maximum distance from breeding
ponds which support previous provincial habitat management zones of at least 500 m around
breeding ponds to maintain connectivity (BCMFLNRORD 2014). A recent review of 162
publications (Correa Ayram et al. 2016) revealed that management plans, for a variety of
species, stress the importance of habitat connectivity. Connectivity is crucial for species with
biphasic life cycles, as demonstrated by the Natterjack Toad (Bufo calamita) in mainlyartificial habitats in Southern Belgium (Stevens and Baguette 2008) and the endangered
Houston Toad (Bufo houstonensis) on a Boy Scouts of America Ranch in Texas (Vandewege
et al. 2013). Breeding ponds are necessary for recruitment, but the majority of a spadefoot’s
life is spent on the terrestrial landscape.

60
Healthy small mammal communities (especially burrowing species) should be maintained
within spadefoot habitat management zones. At the site of my study, small mammal burrows
were utilized as daytime retreat sites by spadefoots ≈ 27% of the time, suggesting that these
features may provide critical refuge in areas of disturbance with highly compacted soil. It has
been suggested that terrestrial, burrowing anurans make use of other species burrows for
refuge, potentially saving energy and alleviating desiccation (Denton and Beebee 1993;
Parris 1998).
Variations in Life Stage
My work suggests that favourable habitat attributes for metamorphic spadefoots may be more
specific than that of adults, requiring a more complex, holistic approach to habitat
management for this species. Future populations of the spadefoot rely on successful
emergence of the metamorphs from breeding ponds onto the terrestrial landscape.
Metamorphs, compared to adults, are likely at a greater risk of mortality due to desiccation
and predation (Beebee 2013; Cabrera-Guzmán et al. 2013). Metamorphs also experience
high mortality when they emerge from the breeding ponds and seek refuge on an unknown
terrestrial landscape (Rothermel and Semlitsch 2006; Roznick and Johnson 2009). This
supports my microcosm results. There was a clear indication that metamorphs selected moist
terrestrial habitat with cover immediately after exiting the breeding pond. This is in contrast
to adult behaviour in which there was little to no significant difference in vegetation cover
and soil moisture between used and available daytime retreat sites. Natural and/or artificial
cover material (e.g. vegetation, coarse woody debris, cover boards), placed within the pond,
staggered along the perimeter of the pond (within 0.3 m) and at various distances from the
pond edge would provide shelter and moisture for metamorphs as they transition to the
terrestrial landscape and would offer protection for adults during the breeding season.
LIMITATIONS AND FUTURE RESEARCH PRIORITIES
The spadefoot metamorph microcosm study attempted to replicate their natural environment
in an effort to gain insight into their post-metamorphic behaviour (e.g. microhabitat
preference immediately upon emergence), which is relatively unknown. Replicating natural
environments can be challenging, due to uncontrollable factors (e.g. weather). The

61
timeframe to conduct the study was limited to the rate of metamorphosis of the individuals,
which varied considerably between ponds. Metamorph movement pattern studies are
difficult due to their size (excludes telemetry), and their reliance on the aquatic habitat
(excludes fluorescent powdering), but would further our understanding of habitat
requirements during the critical transition period between land and water.
Further studies to investigate water and soil chemistry are recommended. One such study
could explore spadefoot tolerance levels to metal concentrations in soil and water. Metal
concentrations may be significant on disturbed landscapes, and are not always readily
apparent through human observation. Levels of chloride concentration were found to
negatively influence breeding sites of the Caucasian Salamander (Mertensiella caucasica) at
lower thresholds than other amphibians in the Western Lesser Caucasus (Turkey and
Georgia; Sayım et al. 2009). This suggests amphibian tolerance levels to chemical exposure
should be explored in further detail.
My research has proven that not all breeding ponds are utilized at the same time, and adult
spadefoots can be up to 1 km away from a breeding pond during the time period that
breeding would be expected. A common ‘false-negative’ error in amphibian inventory is
making the conclusion that a species is absent in an area simply because they are not
detected. Environmental DNA (eDNA) may be useful in determining the presence of
spadefoots on the landscape where breeding ponds are lacking, do not persist long enough to
facilitate breeding, or where breeding simply did not occur. Although eDNA rapidly
degenerates in water, it can persist in soil for decades (Thomsen and Willerslev 2015);
therefore, detecting presence of a species, even though breeding did not occur or individuals
were not observed. Further exploration of eDNA monitoring methods is listed as an essential
(i.e. urgent) recovery action within the BC Recovery Plan for the Great Basin Spadefoot
(BCSIRAWG 2017).

62
CONCLUDING REMARKS
My study provides room for optimism in the conservation of this iconic grassland species,
suggesting that spadefoots can persist in altered habitats in this region. Due to either
anthropogenic or natural disturbance, the grasslands of southern BC are rarely static. Warren
and Büttner (2008) and Rose et al. (2015) proposed that some levels of disturbance were
favourable to amphibian species at risk. Keeping this in mind, it is imperative that we
understand spadefoot habitat requirements at all life stages to create specific strategies for
recovery.
In conducting this research, I built upon past research, brought forth more questions, and
most importantly, in my opinion, taught myself the significance of persistence, endurance
and the ability to work with one’s surroundings in order to cope with a changing world. On a
narrow scale, my research focussed on the habitat requirements of the Great Basin Spadefoot
in the disturbed arid grasslands. Yet, on the broad scale, that resource managers make
decisions that can either help or hamper our environment and both the large and small
species that reside within it. We must work together to promote biodiversity and holistic
management. Spadefoots have been able to survive in these harsh environments through
time, working with their environment rather than against it. We must search beyond the
norm and commit to learn as much as we can about these enigmatic creatures in a concerted
effort to cohabitate in an ever-changing world.
LITERATURE CITED
BC Ministry of Forests, Lands, Natural Resource Operations and Rural Development
(BCMFLNRORD). 2014. Guidelines for Amphibian and Reptile Conservation.
Available: www.env.gov.bc.ca/wld/documents/bmp/HerptileBMP_complete.pdf
BC Southern Interior Reptile and Amphibian Working Group (BCSIRAWG). 2017.
Recovery plan for the Great Basin Spadefoot (Spea intermontana) in British
Columbia. Prepared for the BC Ministry of Environment. Victoria, BC. 40 pp.
Repr. of 1st ed., Southern Interior Reptile and Amphibian Working Group, Victoria,
BC. 40 p. (Orig. pub. 2016).
Beebee, T. 2013. Amphibians and reptiles: Naturalists’ handbooks 31. First edition.
Pelagic Publishing, Exeter, UK.

63
Cabrera-Guzmán, E., M.R. Crossland, G.P. Brown, and R. Shine. 2013. Larger body size at
metamorphosis enhances survival, growth and performance of young Cane Toads
(Rhinella marina). PLoS One. 8(7): 1-10.
Coelho, A.J.A. 2015. Assessing climate change induced declines in ponds in British
Columbia’s semi-arid grasslands. MSc thesis, Thompson Rivers University,
Kamloops, BC, Canada. Available:
http://www.tru.ca/__shared/assets/Coelho_thesis34900.pdf.
Correa Ayram, C.A., M.E. Mendoza, A. Etter, and D.R. Pérez Salicrup. 2016. Habitat
connectivity in biodiversity conservation: A review of recent studies and applications.
Progress in Physical Geography. 40(1): 7-37.
COSEWIC. 2007. COSEWIC assessment and update status report on the Great Basin
Spadefoot (Spea intermontana) in Canada. Committee on the Status of Endangered
Wildlife in Canada. Ottawa. vii + 34 pp.
(http://www.sararegistry.gc.ca/virtual_sara/files/cosewic/sr_spea_intermontana_e.pdf).
Denton, J.S., and T.J.C. Beebee. 1993. Summer and winter refugia of Natterjacks (Bufo
calamita) and Common Toads (Bufo bufo) in Britain. Herpetological Journal. 3: 9094.
Garner, J.L. 2012. Movement and habitat-use of the Great Basin Spadefoot (Spea
intermontana) at its northern range limit. MSc thesis, Thompson Rivers University,
Kamloops, BC, Canada. Available:
http://www.tru.ca/__shared/assets/Garner_Thesis_201233086.pdf.
Melcher, C.P., K.R. Sherrill, G. Reese, and N.B. Carr. 2015. Spadefoot assemblage. In
Wyoming Basin Rapid Ecoregional Assessment: U.S. Geological Survey Open-File
Report 2015–1155, 896 p., http://dx.doi.org/10.3133/ofr20151155.
Parris, M.J. 1998. Terrestrial burrowing ecology of newly metamorphosed frogs (Rana
pipiens complex). Canadian Journal of Zoology. 76: 2124–2129.
Pearson, P.G. 1955. Population ecology of the Spadefoot Toad, Scaphiopus h. holbrooki
(Harlan). Ecological Monographs. 25: 233-267.
Pechmann, J.H.K., R.A. Estes, D.E. Scott, and J. Whitfield Gibbons. 2001. Amphibian
colonization and use of ponds created for trial mitigation of wetland loss. Wetlands.
21(1): 93-111.
Rose, J.P., O.J. Miano, G.R. Cottle, R.E. Lovich, R.L. Palmer, and B.D. Todd. 2015. A
herpetological inventory of Naval Air Station Fallon, Churchill County, Nevada.
Western North American Naturalist. 75(4): 526-534.
Rothermel, B.B., and R.D. Semlitsch. 2006. Consequences of forest fragmentation for
juvenile survival in Spotted (Ambystoma maculatum) and Marbled (Ambystoma
opacum) Salamanders. Canadian Journal of Zoology. 84: 797-807.
Roznik, E.A., and S.A. Johnson. 2009. Burrow use and survival of newly metamorphosed
Gopher Frogs (Rana capito). Journal of Herpetology. 43(3): 431-437.

64
Sarell, M. 2004. Great Basin Spadefoot, Spea intermontana. In accounts and measures for
managing identified wildlife – Accounts V. 2004 (7 pp.). Ministry of Water, Land
and Air Protection. Victoria, BC, Canada.
Sayım, F., E. Başkale, D. Tarkhnishvili, and U. Kaya. 2009. Some water chemistry
parameters of breeding habitats of the Caucasian Salamander, Mertensiella caucasica
in the Western Lesser Caucasus. Ecology. 332(5): 464-469.
Stevens, V.M., and M. Baguette. 2008. Importance of habitat quality and landscape
connectivity for the persistence of endangered Natterjack Toads. Conservation
Biology. 22(5): 1194-1204.
Thomsen, P. F., and E. Willerslev. 2015. Environmental DNA – an emerging tool in
conservation for monitoring past and present biodiversity. Biological Conservation.
183: 4-18.
Vandewege, M.W., T.M. Swannack, K.L. Greuter, D.J. Brown, and M.R.J. Forstner. 2013.
Breeding site fidelity and terrestrial movement of an endangered amphibian, the
Houston Toad (Bufo houstonensis). Herpetological Conservation and Biology. 8(2):
435−446.
Warren, S.D., and R. Büttner. 2008. Relationship of endangered amphibians to landscape
disturbance. Journal of Wildlife Management. 72(3): 738-744.

65

APPENDIX A. MAP OF ARTIFICIAL POND LOCATIONS

66

APPENDIX B. ARTIFICIAL POND CONSTRUCTION

A

B

C

D

(A) Layout of artificial pond site #2 in November 10, 2013. (B) Site #2 after exposed
polyethylene geomembrane liner was covered with burlap. Note completion of barbed-wire
fence surrounding the perimeter. (C) Site #2 on May 1, 2014. (D) The addition of Ponderosa
Pine branch (Pinus ponderosa) visible in the center of the ephemeral pond at Site #3. Photos
by author.

67
APPENDIX C. SPADEFOOT RELOCATION SUMMARY TABLE
Spadefoot #2014M08
Marker #
(relocations)

Spadefoot #2014M15

Spadefoot #2014F01

Date of
Relocation

Distance from
Previous
Location (m)

Date of
Relocation

Distance from
Previous
Location (m)

Date of
Relocation

Distance from
Previous
Location (m)

R1

15-May-14

n/a

10-Jun-14

n/a

17-Jun-14

n/a

R2

16-May-14

5.2

11-Jun-14

8

18-Jun-14

45.2

R3

19-May-14

67.3

13-Jun-14

0

20-Jun-14

0

R4

20-May-14

1.9

16-Jun-14

18.5

23-Jun-14

17.1

R5

22-May-14

58.0

18-Jun-14

141.7

25-Jun-14

31.2

R6

24-May-14

14.2

20-Jun-14

15.2

26-Jun-14

54.25

R7

26-May-14

15.1

23-Jun-14

0

30-Jun-14

71.7

R8

27-May-14

0

25-Jun-14

62

02-Jul-14

84.1

R9

30-May-14

61.5

26-Jun-14

309.3

04-Jul-14

22.7

R10

02-Jun-14

61.5

30-Jun-14

0

07-Jul-14

0

R11

04-Jun-14

0

02-Jul-14

0

09-Jul-14

0

R12

06-Jun-14

0

04-Jul-14

0

11-Jul-14

0

R13

09-Jun-14

1.0

09-Jul-14

367.5

14-Jul-14

22.9

R14

11-Jun-14

1.0

16-Jul-14

0

R15

13-Jun-14

0

17-Jul-14

0

R16

16-Jun-14

94.1

21-Jul-14

39.4

R17

18-Jun-14

47.5

23-Jul-14

39.4

R18

20-Jun-14

141.4

25-Jul-14

50.6

R19

23-Jun-14

0

28-Jul-14

28.5

R20

26-Jun-14

93.9

30-Jul-14

31.5

R21

30-Jun-14

90.2

R22

02-Jul-14

0

R23

04-Jul-14

49.3

R24

07-Jul-14

91.2

R25

09-Jul-14

24.4

R26

11-Jul-14

12.2

R27

14-Jul-14

0

R28

16-Jul-14

0

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APPENDIX D. RADIO-TELEMETRY DATA SUMMARY TABLE

Spadefoot ID*

Number of
Relocations

Distance from Breeding Pond (m)

Burrow Type

Max

Min

Avg

Self-made

Small
Mammal

Days
Transmitted

Weight Change (g)
At Capture

At Release

Difference

2013M01

9

65.5

14

33.9

3

0

11

13.28

13.28

0

2013M02

16

59

2

33.0

2

0

17

17.42

15.36

- 2.06

2013M03

15

115.7

0.8

29.0

2

0

16

19.96

19.44

- 0.52

2013M04

27

322.7

2.3

113.3

13

6

28

17.63

20.51

2.88

2013M05

13

125.8

28.4

67.8

2

2

14

17.22

15.73

- 1.49

2013M06

13

188.1

30

116.0

1

4

14

23.44

27.41

3.97

2013M07

5

400

396.6

398.3

1

0

5

19.18

19.18

0

2013F01

21

435

294

384.3

2

1

22

19.43

18.76

- 0.67

2013F02

15

399.6

6.1

155.0

7

2

16

23.71

19.80

- 3.91

2013F03

7

300

9.8

167.2

5

1

7

18.36

20.17

1.81

2013F04

16

205.2

179.4

194.5

1

1

22

20.65

20.65

0

2013F05

14

143.1

135

139.8

1

1

17

21.19

21.19

0

2013F06

4

440.2

414.8

427.5

-

-

7

25.00

25.00

0

2014M01

25

273

10

141.1

3

0

63

17.36

17.60

0.24

2014M02

3

19.7

12.2

15.1

-

-

5

14.99

14.99

0

2014M03

28

362.7

5

120.6

5

0

63

14.19

13.96

- 0.23

2014M04

10

505.7

7.4

377.5

-

-

19

17.80

16.83

- 0.97

69

Spadefoot ID*

Number of
Relocations

Distance from Breeding Pond (m)

Burrow Type

Max

Min

Avg

Self-made

Small
Mammal

Days
Transmitted

Weight Change (g)
At Capture

At Release

Difference

2014M05

20

255.3

3.1

27.2

4

1

43

15.86

17.75

1.89

2014M06

9

111.4

4

19.0

1

0

16

17.62

17.62

0

2014M07

9

60.7

4.5

31.0

1

0

16

17.35

17.35

0

2014M08

28

144.5

3.9

25.4

4

1

63

14.82

18.59

3.77

2014M09

2

-

-

-

-

-

2

14.95

14.95

0

2014M10

25

288.7

5.5

126.8

2

0

63

18.16

15.40

- 2.76

2014M11

20

381

3.1

208.4

2

3

43

16.92

18.40

1.48

2014M12

9

37

6.7

14.3

1

0

16

17.39

17.39

0

2014M13

6

58.3

57.3

38.4

1

0

13

14.38

10.93

- 3.45

2014M14

5

22

4.8

11.7

1

0

10

15.00

14.05

- 0.95

2014M15

13

369.2

7.6

126.1

1

0

30

16.01

18.51

2.5

2014M16

5

210.9

150.5

198.8

1

1

10

16.28

16.28

0

2014F01

20

325.7

243.7

292.6

7

2

44

21.25

20.20

- 1.05

2014F02

8

249.1

140.3

189.0

4

1

18

23.67

23.67

0

2014F03

15

338.2

317.7

336.8

1

1

32

23.40

23.20

- 0.2

2014F04

7

460.7

335.8

367.9

1

2

16

25.60

25.60

0

Average

13.4

239.8

88.6

154

2.8

1.0

23.7

18.47

18.48

0.01

Sum

442

80

30

781

609.47

609.75

0.28

Max

28

505.7

414.8

13

6

63

25.6

27.4

3.97

Min

2

19.7

0.8

1

0

2

13.28

10.93

-3.91

* Gender is indicated by either ‘M’ or ‘F’ in the numbered sequence in the Spadefoot ID.

70
APPENDIX E. NEW GOLD - NEW AFTON MINE GREAT BASIN SPADEFOOT AND WESTERN
TOAD MANAGEMENT PLAN – CREATED BY AUTHOR

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