NORTHERN LEOPARD FROG AND WETLAND ASSESSMENT
IN SW 30-5-13 W2M
FOR CENOVUS ENERGY INC.
November 2011
7926
Prepared for:
Cenovus Energy Inc.
Calgary, Alberta
Prepared by:
TERA Environmental Consultants
Suite 1100, 815 - 8th Avenue S.W. Calgary, Alberta T2P 3P2
Ph: 403-265-2885
Cenovus Energy Inc.
Northern Leopard Frog Survey and Wetland Assessment
November 2011
7926
TABLE OF CONTENTS
Page
1.0 INTRODUCTION.............................................................................................................................. 1 2.0 METHODS ....................................................................................................................................... 3 2.1 2.2 2.3 Northern Leopard Frog Assessment ................................................................................... 3 Wetland Assessment .......................................................................................................... 3 2.2.1 Wetland Classification ............................................................................................ 3 2.2.2 Wetland Health Assessment .................................................................................. 4 Literature Review ................................................................................................................ 5 3.0 RESULTS OF THE NORTHERN LEOPARD FROG ASSESSMENT ............................................. 6 4.0 RESULTS OF THE WETLAND ASSESSMENT .............................................................................. 7 4.1 4.2 5.0 RESULTS OF THE LITERATURE REVIEW.................................................................................... 9 5.1 5.2 5.3 6.0 Wetland Classification Results............................................................................................ 7 Wetland Health Assessment Results .................................................................................. 7 Biology and Natural History ................................................................................................ 9 5.1.1 Species Description ............................................................................................... 9 5.1.2 Distribution and Range .......................................................................................... 9 5.1.3 Habitat .................................................................................................................... 9 5.1.4 Biology ................................................................................................................. 10 Potential Threats and Sensitivities .................................................................................... 10 5.2.1 Contaminants ....................................................................................................... 10 5.2.2 Disease ................................................................................................................ 11 5.2.3 Habitat Loss, Fragmentation and Degradation .................................................... 12 5.2.4 Water Quality and Management .......................................................................... 13 Northern Leopard Frogs as an Indicator Species ............................................................. 13 DISCUSSION ................................................................................................................................. 14 6.1 6.2 6.3 Northern Leopard Frog Survey ......................................................................................... 14 Wetland Assessment ........................................................................................................ 14 Water Quality Data Review ............................................................................................... 15 7.0 KEY FINDINGS .............................................................................................................................. 16 8.0 REFERENCES............................................................................................................................... 17 8.1 8.2 8.3 Personal Communications ................................................................................................ 17 Literature Cited.................................................................................................................. 17 GIS Data and Mapping References .................................................................................. 19 Appendix A
Appendix B
Photoplates ....................................................................................................................... 20
Site Cards ......................................................................................................................... 21
Figure 1
Aerial Overview of SW 30-5-13 W2M ................................................................................. 2
LIST OF APPENDICES
LIST OF FIGURES
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LIST OF TABLES
table 1 Wetland Classes Established by Stewart And Kantrud (1971) ........................................................ 3
Table 2 Amphibians Observed in SW 30-5-13 W2m On August 4, 2011 .................................................... 6
Table 3 Wetland Classification Summary .................................................................................................... 7
Table 4 Wetland Health Assessment Results Summary ............................................................................. 7
Table 5 Northern Leopard Frog Toxicological Data for Hydrocarbon Exposure........................................ 11
LIST OF PLATES
Plate 1
Plate 2
Northern leopard frog observed in Wetland 1 in SW 30-5-13 W2M
(August 4, 2011)................................................................................................................ 20
Northern leopard frog observed in Wetland 2 in SW 30-5-13 W2M
(August 4, 2011)................................................................................................................ 20 Page ii
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INTRODUCTION
While conducting initial site reconnaissance in the Rural Municipality of Lomond Number 37 near
Goodwater, Saskatchewan, Cenovus Energy Inc. (Cenovus) field staff observed amphibians which were
believed to be northern leopard frogs in SW 30-5-13 W2M (Figure 1) (the Property). Cenovus retained
TERA Environmental Consultants (TERA) to conduct a northern leopard frog survey in SW 30-5-13 W2M
to confirm the presence of northern leopard frogs onsite and to determine what, if any, mitigative
measures would be required for northern leopard frog protection during subsequent site visits. Cenovus
field staff noted that the northern leopard frogs were observed in wetland habitat on the quarter-section
and requested that TERA conduct a wetland assessment at the same time as the leopard frog survey.
TERA conducted a northern leopard frog survey and wetland assessment at four wetlands located in
SW 30-5-13 W2M on August 4, 2011.
Following TERA’s northern leopard frog survey and wetland assessment in SW 30-5-13 W2M, water
samples were collected by TRIUM Environmental (TRIUM) from two of the wetlands (Wetlands 2 and 3).
The water samples were tested to determine if the water quality was in compliance with provincial surface
water quality guidelines (TRIUM 2011).
Cenovus requested that TERA prepare a literature review related to the northern leopard frog, specifically
outlining the sensitivity of this species to a variety of potential contaminants and whether northern leopard
frogs can be considered a reasonable indicator of overall wetland health. Based on available literature,
the water quality data provided by TRIUM was reviewed to determine if the water quality was acceptable
for northern leopard frog. The following report provides the results of the northern leopard frog
assessment, wetland assessment, water quality data analyses and literature review.
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Figure 1
Aerial Overview of SW 30-5-13 W2M
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2.0
METHODS
2.1
Northern Leopard Frog Assessment
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On August 4, 2011, a time-constrained visual encounter survey was conducted by TERA at four wetlands
located in SW 30-5-13 W2M in accordance with the Alberta Sustainable Resource Development (ASRD)
northern leopard frog survey protocol (Kendell 2002). Arsenault (2009) also recommends the methods
outlined by Kendell (2002) be used for northern leopard frog surveys in Saskatchewan. This method
consists of a systematic search of appropriate habitat to record the presence of northern leopard frogs
around each of the four wetlands. TERA also recorded which age classes were observed at each wetland
as well as any other amphibian species observed. Habitat observations were also recorded.
2.2
Wetland Assessment
The wetland assessment was conducted by and completed under the direct supervision of a Qualified
Wetland Aquatic Environment Specialist (QWAES) on August 4, 2011. Wetland assessments were based
on the professional judgment of the wetland specialist who conducted the site visit. General site
information was collected for each of the wetlands assessed and included GPS (UTM) co-ordinates,
photo documentation and notes related to adjacent land use, hydrology, vegetation and habitat potential.
2.2.1
Wetland Classification
The four wetlands located in SW 30-5-13 W2M were classified in the field based on the Classification of
Natural Ponds and Lakes in the Glaciated Prairie Region (Stewart and Kantrud 1971). These
classifications are based on the following information recorded at each wetland:
•
dominant vegetation (e.g., tree, shrub, herbaceous, emergent and/or weed species);
•
hydrology (e.g., surface water presence, movement, depth, sign of groundwater influence and/or
indicators of water quality); and
•
habitat features (e.g., snags, browse evidence, access to open water and sufficient cover).
Wetland classes as per Stewart and Kantrud (1971) range from Class I through Class VI and are
described in Table 1.
TABLE 1
WETLAND CLASSES ESTABLISHED BY STEWART AND KANTRUD (1971)
Wetland Class
Central Zone
Ephemeral
Potholes
(I)
Temporary
Potholes
(II)
Seasonal
Potholes
(III)
Low-prairie
Semipermanent
Potholes
(IV)
Permanent
Lakes
(V)
Alkali Wetlands
(VI)
Wet-meadow
Shallowmarsh
Deep-marsh
Open-water
Intermittent
Alkali
Description
Ephemeral potholes occur in small swales that contain prairie species such as arnicas and white camas, as well as
Kentucky bluegrass.
The wet-meadow zone dominates the deepest part of the wetland area. A peripheral low-prairie zone is usually present.
The central zone is usually dominated by species that can tolerate some salts, such as western wheatgrass, foxtail barley
and salt-grass.
Seasonal potholes are wetlands with a shallow-marsh zone dominating the deepest part of the wetland area. These ponds
are frequently surrounded by a ring of willows with a wet centre containing sedges for freshwater wetlands, or bulrushes in
more brackish wetlands. Pondweeds and mosses may occur in the open-water. Brackish ponds may have halophytic
species in the drawdown area, such as foxtail barley, red goosefoot, oak-leaved goosefoot or summer cypress.
The deep-marsh zone dominates the deepest part of the wetland area. Shallow-marsh, wet-meadow and low-prairie zones
are usually present. Cattails and rushes are typical emergent species, while aquatic plants such as pondweeds,
bladderwort, water-milfoil and water hornwort are found floating in the centre. The edges of brackish semi-permanent
potholes typically contain prairie bulrush, alkali grass and red samphire.
The permanent open-water zone dominates the deepest part of the wetland area. Peripheral deep-marsh, shallow-marsh,
wet-meadow and low-prairie zones are often present. The centre portion of a permanent lake or pothole is typically
open-water, although submerged vegetation may occur, such as widgeon grass.
Alkali zone is characterized by highly saline shallow water that, in its drawn-down (dry) phase, appears as white alkali salt
flats. Peripheral shallow-marsh, wet meadow, and low-prairie zones are usually present and populated with more
salt-tolerant vegetation, such as Nuttall’s salt-meadow grass, salt grass, samphire, western wheatgrass, arrowgrass and
scratch grass. Class VI alkali wetlands vary in the length of time they contain standing water. Some contain water for a brief
time, while others have standing water year-round.
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This methodology provides sufficient information to detail conditions of wetlands and wetland function,
and is part of an Environment Canada recommended approach (Hanson et al. 2008) adapted from
Wisconsin Rapid Assessment Methodology (Wisconsin Department of Natural Resources 2001).
2.2.2
Wetland Health Assessment
The riparian zone is the area between a waterbody and adjacent upland, which is formed as a result of
the interactions between water, soil and vegetation (Alberta Riparian Habitat Management Society 2011).
TERA proposes that riparian health can be used as an indicator and descriptor for overall wetland health.
Wetland (i.e., riparian) health was assessed using the following parameters which are outlined in
Ambrose et al. (2004):
•
ecological status (wildlife usage, vegetation cover, presence of rare vegetation, disturbance caused
undesirable species, invasive plant species);
•
community structure (tree/shrub establishment and regeneration, utilization of trees/shrubs); and
•
site stability (human caused bare ground, human alteration of the physical site).
In addition to assessing ecological function, community structure and site stability, human alteration of
vegetation and artificial water level modification were also assessed.
Each parameter has a different numerical value which it is scored out of and a percentage is calculated
based on the actual score and the total possible score. The percentage the wetland scores corresponds
to one of three categories:
•
healthy: health score of 80-100%. All primary functions of a healthy wetland are operating;
•
healthy with problems: health score of 60-79%. Most but not all primary functions of a healthy range
are operating; or
•
unhealthy: health score of less than 60%. Most functions of a healthy riparian area are severely
impaired.
2.2.2.1
Wetland Function Support to Wetland Health Assessment
Wetland function is used to describe a wetland’s ability to appropriately and simultaneously perform a
process or series of processes related to the habitat, hydrologic and water quality-related attributes within
a wetland ecosystem.
Examples of overall wetland function processes include:
•
•
•
hydrological functions:
−
storing water and energy;
−
recharge aquifers; and
−
reduce and dissipate energy.
water quality functions:
−
trap and store sediment;
−
filter and buffer water; and
−
transformation of nutrients.
habitat functions:
−
growth of living matter;
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−
create primary productivity;
−
diversity of wetland plants; and
−
maintaining biodiversity.
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A wetland’s geographic location may determine its habitat functions and the location of a wetland within a
watershed may determine its hydrologic or water quality functions. Not all wetlands perform all functions
nor do they perform all functions equally well. The wetland type, location, size and proximity to other
wetlands all contribute to the functions a wetland performs. Many factors determine how well a wetland
will perform these functions including: climatic conditions; quantity and quality of water entering the
wetland; and disturbances or alteration within the wetland or the surrounding ecosystem.
Wetland functionality can change throughout the year (e.g., from times of drought to excessive
precipitation) and the importance of the wetland functions can also change depending on conditions.
All of these functional attributes are considered by the QWAES when documenting wetland health
characteristics in the field and collectively, assist with the determination of the overall wetland health
category (e.g., healthy, healthy with problems, unhealthy).
2.3
Literature Review
A literature review was conducted on northern leopard frogs using available published research and
internet searches to provide information on the biology, habitat requirements, potential threats and
sensitivities, and the suitability of this species as an indicator species for wetland health.
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RESULTS OF THE NORTHERN LEOPARD FROG ASSESSMENT
During the time-constrained visual encounter survey, northern leopard frogs were observed at three of the
four wetlands in SW 30-5-13 W2M (Plates 1 and 2, Appendix A). No northern leopard frogs were
observed at Wetland 4; however, wood frogs were observed. Wood frogs were also observed at
Wetlands 1 and 3. The results of the northern leopard frog assessment are presented in Table 2.
TABLE 2
AMPHIBIANS OBSERVED IN SW 30-5-13 W2M ON AUGUST 4, 2011
Number of Adult Northern Leopard Frogs
Number of Juvenile Northern Leopard Frogs
Number of Adult Wood Frogs
Wetland 1
Wetland 2
Wetland 3
Wetland 4
1
2
2
4
-----
2
3
3
----6
The quarter-section was also visited on October 4, 2011 to conduct wildlife monitoring while vehicles and
equipment were active in the area. Three boreal chorus frogs were observed at that time and were moved
away from vehicle and equipment traffic.
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4.0
RESULTS OF THE WETLAND ASSESSMENT
4.1
Wetland Classification Results
During the field assessment, Wetland 1 was determined to be the only naturally occurring wetland on the
quarter-section. Wetlands 2, 3 and 4 were determined to be artificially constructed (i.e., man-made) and
are the result of excavation of three gravel pits. The classification of each wetland is listed below in
Table 3. Site cards providing detailed information on the important characteristics of each of the four
wetlands are provided in Appendix B.
TABLE 3
WETLAND CLASSIFICATION SUMMARY
Wetland
Wetland 1
Wetland 2
Wetland 3
Wetland 4
4.2
Wetland Classification
Site Card Number
Class III
artificially constructed (Class IV)
artificially constructed (Class III)
artificially constructed (Class IV)
1
2
3
4
Wetland Health Assessment Results
All four of the wetlands in SW 30-5-13 W2M scored below 60% resulting in an overall wetland health
rating of unhealthy. The unhealthy rating primarily results from following:
•
the occurrence of bare ground areas where vegetation has been removed or suppressed;
•
the presence of invasive (i.e., thistle sp.) and disturbance-caused (e.g., brome sp., foxtail barley)
opportunistic species out-competing the naturally occurring vegetation species; and
•
the alteration of the natural wetland habitat from cattle grazing and from ground disturbance due to
gravel excavation.
A summary of the wetland health assessment results are presented in Table 4.
TABLE 4
WETLAND HEALTH ASSESSMENT RESULTS SUMMARY
Health Criteria
Vegetative Cover of Wetland
Area
Invasive Plant Species
Wetland 1
Preferred Tree and Shrub
Establishment
Wetland 3
Wetland 4
•
5-15% bare soil (4/6)
•
15-25% bare soil (2/6)
•
5-15% bare soil (4/6)
•
15-25% bare soil (2/6)
•
<1-15% total canopy
cover/several patches
plants (1/6)
Occurrence of perennial
sow-thistle and
creeping (Canada)
thistle
•
<1-15% total canopy
cover/several patches
plants (1/6)
Occurrence of perennial
sow-thistle and
creeping thistle
•
<1-15% total canopy
cover/several patches
plants (1/6)
Occurrence of perennial
sow-thistle and
creeping thistle
•
<1-15% total canopy
cover/several patches
plants (1/6)
Occurrence of perennial
sow-thistle and
creeping thistle
•
•
25-45% covered (1/3)
occurrence of brome,
crested wheatgrass,
dandelion, foxtail barley
•
more than 45% covered
(0/3)
occurrence of
sweet-clover and
crested wheatgrass
•
more than 45% covered
(0/3)
occurrence of
sweet-clover, brome
and crested wheatgrass
•
•
5-15%
seedlings/saplings (4/6)
willow sp.
•
5-15%
seedlings/saplings (4/6)
willow sp.
•
5-15%
seedlings/saplings (4/6)
alder
•
•
Disturbance-caused
Undesirable Species
Wetland 2
•
•
•
•
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•
•
•
•
•
more than 45% covered
(0/3)
occurrence of
sweet-clover, brome,
foxtail barley and
crested wheatgrass
absent (N/A)
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TABLE 4 Cont'd
Health Criteria
Wetland 1
Wetland 2
Wetland 3
Wetland 4
Utilization of Preferred Trees
and Shrubs
•
•
0-5% browsed (3/3)
cattle present, but not
utilizing
seedling/saplings
•
•
0-5% browsed (3/3)
Minimal sedge browsing
•
•
0-5% browsed (3/3)
No evidence of
browsing observed
•
absent (N/A)
Human Alteration of Riparian
Vegetation
•
more than 35% altered
(0/6)
land use has altered
wetland
more than 35% altered
(8/12)
land use has altered
wetland
•
more than 35% altered
(0/6)
gravel pit
•
more than 35% altered
(0/6)
gravel pit
•
more than 35% altered
(4/12)
gravel pit
•
•
•
more than 35% altered
(4/12)
gravel pit
more than 35% altered
(0/6)
no established riparian
area
more than 35% altered
(8/12)
no established riparian
area
•
•
•
more than 15% bare
(0/6)
gravel pit
cattle utilization
•
•
1-5% bare ground (4/6)
at wetland margins
•
•
•
less than 5-15% bare
(2/6)
trail near wetland
gravel pit
•
•
more than 15% bare
(0/6)
adjacent land use
cattle utilization
•
no artificial change (9/9)
•
no artificial change (9/9)
•
no artificial change (9/9)
•
no artificial change (9/9)
•
•
56% (32/57)
unhealthy
•
•
40% (23/57)
unhealthy
•
•
51% (29/57)
unhealthy
•
•
42% (20/48)
unhealthy
•
Physical Human Alteration of
Riparian Area
•
•
Human-caused Bare Ground
Degree of Artificial
Addition/Removal of Water
Health Rating
•
•
•
•
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•
•
•
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RESULTS OF THE LITERATURE REVIEW
Amphibians often act as indicators of ecosystem health (Committee on the Status of Endangered Wildlife
in Canada [COSEWIC] 2009). Their absence from otherwise appropriate habitat could be indicative of an
environmental concern, either natural or anthropogenic in origin. Northern leopard frog populations have
been in decline for over 40 years but are still one of the most widespread amphibians in Canada
(COSEWIC 2009). The species is listed as Vulnerable (S3) in the province of Saskatchewan
(NatureServe 2011) and two of the three separate populations are federally-listed on Schedule 1 of the
Species at Risk Act. The Western Boreal/Prairie population found in Alberta, Saskatchewan and
Manitoba, is listed as Special Concern and the Rocky Mountain population, localized to the Creston
Valley in British Columbia (BC), is listed as Endangered (COSEWIC 2009). A species listed as Special
Concern is said to be “A wildlife species that may become a threatened or endangered species because
of a combination of biological characteristics and identified threats (COSEWIC 2009)”, whereas an
Endangered species is at risk of extirpation or extinction (COSEWIC 2009).
5.1
Biology and Natural History
5.1.1
Species Description
The northern leopard frog is a mid-sized frog of the recently reorganized genus Lithobates
(COSEWIC 2009). The overall dorsal colour ranges from brown to green with dark-coloured spots
accented by light-coloured rings along the edges of each spot (ASRD 2003, COSEWIC 2009,
Wind 2002). Another distinguishing feature are a pair of light-coloured ridges which run parallel to each
other beginning behind each eye and running the length of the back down to the hind legs (ASRD 2003,
COSEWIC 2009, Wind 2002). Females are typically larger than males with a maximum snout to vent
length of 110 mm (ASRD 2003, COSEWIC 2009).
5.1.2
Distribution and Range
COSEWIC (2009) has divided the Canadian northern leopard frog population into three designatable
units (DU) which include: the Rocky Mountain DU; the Prairie/Western Boreal DU; and the Eastern DU.
The Canadian range of the northern leopard frog covers a broad area from Labrador to southeastern BC
and north to Great Slave Lake in the Northwest Territories (COSEWIC 2009). This area encompasses
2.6 million km2.
5.1.3
Habitat
Northern leopard frogs require three different habitat types to complete their life cycle requirements
(ASRD 2003, COSEWIC 2009). Breeding habitats are characterized as semi-permanent or permanent
wetlands with a maximum water depth of 2 m. A neutral pH and absence of fish in breeding wetlands are
also important features (COSEWIC 2009). Wetlands typically used by breeding northern leopard frogs
include: beaver ponds; borrow pits; channels; ditches; dugouts; lake edges; marshes; oxbows;
permanently flooded meadows; swamps; springs; and stream backwaters. Seasonal wetlands are also
utilized for breeding as long as they do not desiccate prior to August to allow tadpoles to metamorphose
(ASRD 2003, COSEWIC 2009).
Once breeding is complete, adults move to summer foraging areas (ASRD 2003, COSEWIC 2009).
These areas primarily consist of open areas dominated by low-growing vegetation up to 30 cm. Fresh
meadows, shallow marshes and unmown pastures are examples of summer foraging habitat
(ASRD 2003, Wind 2002). Bare areas, areas of mowed or overgrazed vegetation, tall vegetation over 1 m
and heavily treed areas are all avoided as summer foraging habitat (ASRD 2003, COSEWIC 2009).
Northern leopard frogs are one of few amphibian species in Canada that overwinter in water
(ASRD 2003, COSEWIC 2009). Overwintering sites are typically permanent waterbodies deep enough
that they do not freeze to the bottom with low water temperatures and high dissolved oxygen content
(ASRD 2003, COSEWIC 2009, Wind 2002). Sites that meet these criteria include creeks, lakes, ponds,
rivers, spillways below dams, springs and streams (ASRD 2003, COSEWIC 2009).
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Biology
Northern leopard frogs emerge from hibernation sites when ice melts and water temperatures reach
7-10°C (ASRD 2003, COSEWIC 2009). Migrations of up to 1.6 km to breeding ponds (ASRD 2003,
COSEWIC 2009) begin on rainy nights with adults dispersing before juveniles. Breeding is a
temperature-dependent process which typically occurs from late April to late June. Sexually mature males
arrive at breeding ponds first and begin calling once water temperatures reach 10°C and air temperatures
reach 15°C. Northern leopard frogs are believed to exhibit breeding site fidelity. Attracted by the calling
males, females arrive at breeding ponds where breeding and egg-laying takes place shortly afterwards
(ASRD 2003, COSEWIC 2009).
Females lay eggs in shallow water attached to submerged vegetation or on the pond bottom
(ASRD 2003, COSEWIC 2009). Females commonly lay over 3,000 eggs in a single clutch, with larger
females capable of laying 7,000 eggs per clutch (COSEWIC 2009, Wind 2002). Like breeding, hatching of
tadpoles is temperature-dependent and occurs 5 to 11 days after oviposition. Success rates of tadpole
hatching ranges widely, with developmental failure, physical displacement of the egg mass and egg mass
break-up being the most common causes of egg mortality (ASRD 2003, COSEWIC 2009).
Tadpole metamorphosis occurs 60 to 90 days after hatching depending on temperature, pH, diet,
dissolved oxygen, predation and tadpole density (ASRD 2003, COSEWIC 2009). Metamorphosis occurs
in July or early August and it takes several weeks for tadpoles to complete the transformation. Tadpoles
are herbivores, feeding on aquatic vegetation, algae and detritus until metamorphosis when they become
carnivores. Prey items of adult and metamorphosed northern leopard frogs include arthropods (insects
and arachnids), small birds, garter snakes, fish and other frogs including newly transformed northern
leopard frogs (ASRD 2003, COSEWIC 2009).
Adult northern leopard frogs migrate to summer foraging areas shortly after breeding using mesic
corridors to avoid desiccation. Juveniles disperse from breeding ponds in all directions and have been
known to migrate at least 500 m to summer foraging areas. They remain at the summer foraging areas
until late summer or early fall and then begin migrating to overwintering sites (ASRD 2003,
COSEWIC 2009).
5.2
Potential Threats and Sensitivities
Northern leopard frogs and amphibians in general are sensitive to a wide range of threats. Since they
move between three distinct habitat types every season to perpetuate their life cycle, the northern leopard
frog is particularly susceptible to contamination, disease, habitat loss, fragmentation and degradation.
5.2.1
Contaminants
Different types of contaminants have different lethal and sub-lethal effects on northern leopard frogs. Two
of the most common forms of environmental contamination are pesticides (herbicides, fungicides,
insecticides) and polycyclic aromatic hydrocarbons (PAHs) which are found in crude oil and petroleum
wastewater (Garrigues 2004). Other forms of environmental contamination which impact the northern
leopard frog include heavy metals and salinity (COSEWIC 2009).
Agrochemicals such as pesticides are known to cause a wide range of effects on wildlife including
reproductive disorders, reduced growth rates and physical and behavioural abnormalities
(Shenoy et al. 2009). Pesticides also deplete prey populations for adults and juveniles which can
ultimately lead to trophic cascades (COSEWIC 2009). Shenoy et al. (2009) used lab experiments on
northern leopard frog tadpoles to measure the lethal and sub-lethal effects of Endosulfan and Mancozeb,
two common pesticides. Exposure to both pesticides, even at low levels common in agricultural areas,
resulted in tadpole mortality and reduced growth. Atrazine, a commonly used herbicide, is reported to be
acutely toxic and causes feminization of amphibians (COSEWIC 2009). Atrazine, along with other
pesticides have been found to disrupt the immune and endocrine system of northern leopard frogs of all
life stages (COSEWIC 2009). Runoff from agricultural lands can result in excessive growth of aquatic
vegetation which can cause winterkill in wetlands used for overwintering and increased deformities
(COSEWIC 2009). Nitrates, found in fertilizers, have also been linked to decreased tadpole survivorship
as well as lethargy, weight loss and abnormalities (COSEWIC 2009).
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Stabenau et al. (2006) states that the permeability of amphibian skin is what likely allows lipophilic PAHs
to enter the body of northern leopard frogs. Some PAHs are capable of disrupting the structure of DNA
causing mutations (Marquis et al. 2006). A study conducted by Marquis et al. (2006) on toxicity of
common frog (Rana temporaria) to three PAHs (naphthalene, phenanthrene and pyrene) revealed
mortality rates of nearly 50% within the first few hours of a 96 hour exposure trial. They also cited results
of other studies which found that common frogs are also sensitive to nitrogenous fertilizers and
polychlorinated biphenyls. Stabenau et al. (2006) did not report mortality from exposure to naphthalene
alone, but instead their study focused on uptake, accumulation and elimination. They found that
naphthalene exposure caused a reduction in excretion of CO2 but after eight hours, excretion rates
returned to normal levels. They also reported that naphthalene accumulation in body tissues was easily
eliminated once exposed frogs were introduced to clean water. Although acute toxicity was not noted, it is
possible that chronic exposure could result in mortality. The differences between these two studies may
suggest a synergistic effect of multiple PAHs on frogs.
The Reptile and Amphibian Toxicology Literature Database is a compilation of toxicological data of
different types of contaminants and their effects on different amphibian species (Pauli et al. 2000).
Table 5 presents relevant lethal and sub-lethal concentrations of hydrocarbons in the following three
different categories of studies: acute laboratory studies; non-acute laboratory studies; and frog embryo
teratogenesis assays – Xenopus (FETAX), which is a standardized assay to determine the toxicity of
amphibians in the developmental stages using South African clawed frog (Xenopus laevis) embryos
(Pauli et al. 2000).
TABLE 5
NORTHERN LEOPARD FROG TOXICOLOGICAL DATA FOR HYDROCARBON EXPOSURE
Contaminant
Life Stage
Acute Laboratory Studies
anthracene
embryo
anthracene
embryo
benzene
embryo-larvae
fluoranthene
embryo
toluene
embryo-larvae
Non-acute Studies
benzo(a)pyrene adult
naphthalene
adult
naphthalene
adult
phenanthrene
adult
FETAX
benzo(a)pyrene embryo
benzo(a)pyrene embryo
catechol
embryo
catechol
embryo
Source:
Exposure Type
Effect Observed
Concentration (ppm)
immersion
immersion
immersion
immersion
immersion
50% mortality (30 min LC50)
50% mortality (5 hr LC50)
50% mortality (24 hr LC50)
50% mortality (1 hr LC50
50% mortality (24 hr LC50)
0.065
0.025
3.66
0.09
0.39
prepared tissue sample
prepared tissue sample
prepared tissue sample
prepared tissue sample
genotoxicity (DNA damage)
physiological effects
physiological effects (30 min EC50)
physiological effects
0.001
1-30
4.4
100
immersion
immersion
immersion
immersion
50% malformations (96 hr EC50)
50% mortality (96 hr LC50)
50% malformations (96 hr EC50)
50% mortality (96 hr LC50)
11
>10
2.7
13.3
Pauli et al. 2000
Heavy metals, specifically cadmium and copper were found to have negative impacts on development,
growth, survival and behaviour of northern leopard frogs (COSEWIC 2009). Zinc was also found to have
a negative association with northern leopard frog distribution (COSEWIC 2009).
Excessive salinity from road salts is acutely toxic to adult northern leopard frogs (COSEWIC 2009).
Salinity was also found to reduce activity levels and weight of tadpoles and caused physical abnormalities
(COSEWIC 2009).
5.2.2
Disease
Disease is an important consideration in the population dynamics of northern leopard frogs since it has
the ability to result in mass mortality events (ASRD 2003, COSEWIC 2009). Daszak et al. (2003)
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mentions chytridiomycosis, ranavirus infection and saprolegniasis as the more prevalent diseases of
northern leopard frogs.
Chytridiomycosis was first discovered in Panama and Australia in 1998 (ASRD 2003, Daszak et al. 2003).
Since then, it has spread to five continents including North America (Daszak et al. 2003) where it has
been found responsible for mass mortalities (COSEWIC 2009, Daszak et al. 2003). It is thought to have
been spread anthropogenically through what Daszak et al. (2003) refers to as “pathogen pollution”, where
humans unknowingly transfer the fungus into new populations that had no previous exposure to the
fungus. Chytridiomycosis is caused by the chytridiomycete fungus Batrachochytrium dendrobatidis
(ASRD 2003, Cohen 2001, COSEWIC 2009, Daszak et al. 2003, Voordouw et al. 2010) which causes a
skin infection in keratinized skin of adult and metamorphosed young-of-the-year and to a much lesser
extent, tadpoles (Cohen 2001, Voordouw et al. 2010). Symptoms of chytridiomycosis include
vascularization of the limbs, sloughing of the skin, lethargy, changes in behaviour, unusual posture
(COSEWIC 2009) and hyperkeratosis (Cohen 2001, Voordouw et al. 2010). Cohen (2001) and
Voordouw et al. (2010) both hypothesize that the hyperkeratosis (thickening of the outer most layer of the
skin) and sloughing of the skin may disrupt cutaneous respiration and osmoregulation. Cohen (2001) also
states that this condition could leave infected frogs susceptible to absorb toxic products produced by the
fungus.
Ranavirus infection is another serious disease which inflicts amphibians, fish and reptiles (Daszak
et al. 2003). Daszak et al. (2003) describes ranavirus as a DNA virus with different strains which can be
species-specific or can affect entire orders or classes of animals. A large number of new strains of
ranavirus have been discovered and reported in recent years (Daszak et al. 2003). A strain of ranavirus
(FV3) is reported to have been responsible for northern leopard frog die-offs in the Estevan,
Saskatchewan area in the years 1999 and 2000 (COSEWIC 2009). Die-offs in southwest Ontario in the
years 2001 and 2002 studied by Greer et al. (2005) were also confirmed to be the result of ranavirus.
Saprolegniasis (common water mould disease) is another fungus-caused disease which has been known
to lead to mortality of northern leopard frog eggs and tadpoles (ASRD 2003, COSEWIC 2009). Eggs laid
close to the surface are most vulnerable since UV-B radiation is believed to compromise the defences of
eggs (ASRD 2003).
Lucke tumour virus, a type of herpes virus, has also been implicated as the cause of mortality in embryos
and overwintering northern leopard frogs (ASRD 2003, COSEWIC 2009).
Helminth parasites, although not a disease, are another affliction of northern leopard frogs (Cohen 2001,
COSEWIC 2009, Daszak et al. 2003). Ribeiroia trematodes, the well-noted parasite in northern leopard
frogs, are known to cause limb deformities in earlier life stages (Cohen 2001, COSEWIC 2009,
Daszak et al. 2003). Cohen (2001) reported that these trematodes were correlated to limb anomalies and
decreased tadpole survivorship.
5.2.3
Habitat Loss, Fragmentation and Degradation
The loss, fragmentation and degradation of northern leopard frog habitat in North America is believed to
be partly responsible for historical population declines (ASRD 2003, COSEWIC 2009). Since northern
leopard frogs require three different habitat types to complete their life cycle, they are very susceptible to
habitat loss (COSEWIC 2009). In the event that one of these habitats is lost from the landscape and no
local alternative is present, a local extirpation could occur (ASRD 2003, COSEWIC 2009). Agricultural
practices in southern Saskatchewan have impacted 59% of wetland basins and 78% of wetland margins
(COSEWIC 2009). Two national parks and one interprovincial park protect northern leopard frog habitat in
Saskatchewan, Grasslands National Park, Prince Albert National Park and Cypress Hills Interprovincial
Park (COSEWIC 2009).
Not only are the three habitat types of the northern leopard frog important but so are the dispersal
corridors which they use to move between them (COSEWIC 2009). The most common forms of habitat
fragmentation in the range of the northern leopard frog are roads, cultivation and industrial development
(COSEWIC 2009). Road mortalities can be extensive during dispersal (ASRD 2003).
Suitable habitat does not necessarily need to be lost or fragmented to render it unsuitable for northern
leopard frogs. Habitat degradation is most commonly the result of agriculture and development
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(ASRD 2003, COSEWIC 2009). Livestock grazing has been shown to degrade northern leopard frog
habitats by crushing emergent vegetation reducing cover, eroding and rutting shorelines and reducing
water quality parameters (ASRD 2003). Egg masses can also be impacted by being crushed or dislodged
(ASRD 2003). Environmental contamination can also be a form of habitat degradation by reducing prey
populations, changing water quality and altering the wetland vegetation community (COSEWIC 2009).
5.2.4
Water Quality and Management
Northern leopard frogs require certain water quality parameters in the habitats that sustain them
(Wind 2002). The most notable and seemingly most researched among them is pH. Vatnick et al. (1999)
found that northern leopard frogs are more sensitive to low pH than other members of the same genus.
Distribution and abundance of northern leopard frogs are said to be governed in part by the pH of
available breeding sites across the landscape (Schlichter 1981). Schlichter (1981) reported that sperm
motility decreases with the pH of breeding ponds, which in turn reduces the percentage of eggs which are
fertilized during breeding. Schlichter (1981) also reported that at low pH (5), only 50% of fertilized eggs
developed into embryos and embryo development did not occur when the pH was lowered slightly to 4.8.
Long et al. (1995) found that the synergistic effects of pH and UV radiation can be detrimental to embryo
development. A neutral pH is preferred by northern leopard frogs (Wind 2002) and is said to be optimal
for sperm motility (Schlichter 1981). Research conducted by Vatnick et al. (1999) found that adults and
juveniles were also susceptible to low pH, especially upon emergence from overwintering. Acid
precipitation has been implicated as a cause of the lowered pH of lakes and wetlands in North America.
Wind (2002) also mentions hardness, alkalinity, ammonia, nitrites, nitrates and dissolved oxygen as
important abiotic factors which influence northern leopard frogs. Hardness represents the mineral ion
content of water; prolonged exposure to high levels of hardness can cause lesions on the skin of
amphibians. Alkalinity (buffering capacity) interacts with pH to stabilize it and should be closely monitored.
Ammonia, nitrites and nitrates are broken down by natural nitrifying bacteria under balanced conditions.
At elevated pH, more ammonia remains in its un-ionized toxic form. Dissolved oxygen in wetlands utilized
by northern leopard frogs should be 80% saturated or higher which is temperature and
elevation-dependent (Wind 2002). Overwintering ponds should contain 7-10 ppm of dissolved oxygen to
facilitate overwintering (COSEWIC 2009).
CO2 is a natural by-product of respiration and decomposition (Wind 2002). CO2 dissolves in water until
equilibrium is reached with carbonic acid (Shakhashiri 2008). Carbonic acid then dissociates into
carbonate in two steps, each step releasing a hydrogen cation (Shakhashiri 2008). Excessive releases of
CO2 could drastically lower the pH of wetlands from excessive build up and dissociation of carbonic acid
in the water (Wind 2002). Wind (2002) recommends that CO2 levels be maintained at or below 5 ppm.
Roberts et al. (2011) found that CO2 seeps in Italy, which includes bubbling water seeps (CO2 seeps into
a waterbody), were responsible for animal mortalities which included a mass mortality of toads.
As a result of their semi-permeable skin, amphibians typically cannot live in an environment with a higher
concentration of salinity then their own body fluids (Wind 2002). Wind (2002) recommends salinity levels
remain below 2.0 parts per thousand.
5.3
Northern Leopard Frogs as an Indicator Species
The preceding paragraphs of this report demonstrate that northern leopard frogs are a very sensitive
species, known to be affected by low concentrations of contamination (Wind 2002, Pauli et al. 2000).
Environmental stress is first noticed at the population level especially in sensitive species (Welsh and
Ollivier 1998) like the northern leopard frog, which is why amphibians can be important indicators of
ecosystem health (U.S. Geological Survey 2004). Welsh and Ollivier (1998) state that the challenge with
using amphibians as indicators is discerning between natural population fluctuations and unnatural
population declines from anthropogenic sources. Northern leopard frogs are in decline and, due to the
specificity of their habitat requirements, are only present in certain wetlands (Wray and Bayley 2006).
Wray and Bayley (2006) caution that, although the presence of amphibians does indicate an overall
healthy wetland, their absence is not necessarily indicative of an environmental concern or an unhealthy
wetland.
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6.0
DISCUSSION
6.1
Northern Leopard Frog Survey
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Amphibians were found to be present at all four of the wetlands in SW 30-5-13 W2M, with northern
leopard frog presence confirmed at Wetlands 1, 2 and 3. The presence of juvenile frogs at two of the
wetlands (Wetlands 1 and 3) suggests that breeding occurred in 2011. The absence of northern leopard
frogs on the quarter-section on October 4, 2011, corresponds with the time frame for the commencement
of overwintering (ASRD 2003, COSEWIC 2009). It is probable that northern leopard frogs had either
dispersed to wetlands for overwintering or had already begun overwintering in the wetlands in
SW 30-5-13 W2M. The four wetlands in SW 30-5-13 W2M are likely breeding ponds and, therefore, the
following setback distances should be observed (Arsenault 2009).
•
50 m for low level activities (e.g., foot traffic, surveying, small vehicles under one tonne).
•
100 m for medium level activities (e.g., seismic exploration, vehicles over one tonne).
•
200 m for high level activities (e.g., all-season roads, deep well drilling, forest harvesting).
Saskatchewan Ministry of Environment (MOE) determined that temporary foot traffic should not have an
adverse effect once the frogs have passed the tadpole stage and are fully mobile
(Dillabough pers. comm.). In addition, Saskatchewan MOE (Nygren pers. comm.) also recommends the
following mitigative recommendations be implemented for any activities that need to occur within the 50 m
setback distance.
•
Conduct all activities on foot, where feasible.
•
Restrict all vehicle activity to between the hours of 10 AM and 3 PM, when the northern leopard frogs
are least active.
•
Assign a monitor to be onsite during periods of vehicle use to search the area prior to sampling
activities.
These mitigative recommendations were communicated to Cenovus so they could be implemented for all
ensuing site visits.
6.2
Wetland Assessment
Wetlands 2, 3 and 4 are man-made and measure just over 1 ha in surface area each. Wetland 1, which is
a natural Class III wetland, is slightly under 3 ha in surface area. The land use surrounding the four
wetlands in SW 30-5-13 W2M is largely cattle pasture with some hay land. Three of the wetlands
(Wetlands 1, 2 and 4) show evidence of disturbance by cattle ranging from minor (Wetland 2) to extensive
(Wetland 4) and heavily disturbed with pugging evident (Wetland 1). The upland areas in
SW 30-5-13 W2M were found to provide habitat for wildlife including nesting cover for songbirds and
waterfowl, rearing areas for songbirds and waterfowl, spring/fall staging areas for waterfowl and browse
for ungulates.
All of the wetlands in SW 30-5-13 W2M received wetland health assessment scores that classify them as
unhealthy according to Ambrose et al. (2004). This health assessment focuses on the health of the
riparian zone of a wetland and does not take into account measured water quality. The parameters that
were used to gauge the overall health of the riparian zone focused on human-caused disturbance and the
results of that disturbance (e.g., invasive plant species). Scores for the presence of invasive and
disturbance-caused plant species were low for all four wetlands (i.e., 0 or 1) which demonstrate that
undesirable plant species are prevalent onsite. For the two parameters which are not human-disturbance
focused, preferred tree and shrub establishment and utilization of preferred trees and shrubs, the three
wetlands which were scored in those categories all scored 4 out of 6 and 3 out of 3, respectively. The
only other parameter which received full marks was degree of artificial addition or removal of water. The
classification of unhealthy for these four wetlands has no impact on their ability to function as acceptable
aquatic habitat for amphibians.
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6.3
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Water Quality Data Review
TRIUM provided recent water quality data from Wetlands 2 and 3 (TRIUM 2011, Appendix H) for
comparison with relevant concentrations found in current literature. There is limited information in the
literature related to water quality parameters and amphibian health.
The water samples from Wetlands 2 and 3 for F1 and F2 hydrocarbons resulted in readings below the
detection limits of 0.1 and 0.25 ppm. Benzene and toluene concentrations were also found to be below
the detectable limits of 0.0005 ppm and 0.00075 ppm (Pauli et al. 2000).
Recommended levels for alkalinity in the literature varied from 15-50 ppm and 150-250 ppm (Wind 2002).
The alkalinity of the TRIUM water samples ranged from 171-233 ppm and are within the concentration
limits for alkalinity. The recommended levels for hardness range from 75-250 mg/L (Wind 2002).
Hardness of the water samples ranged from 144-226 mg/L and are within the concentration limits for
water hardness.
Nitrite and nitrates, although they are the less toxic by-products of ammonia breakdown, are still harmful
to amphibians in low concentrations (Wind 2002). The recommended nitrite and nitrate levels for
amphibians are <1 mg/L and <50 ppm respectively (Wind 2002). Nitrite and nitrate levels in the TRIUM
water samples were <0.050 ppm individually and, when combined together, the concentration were
<0.071 ppm, which is below the concentration limit.
A pH close to neutral is preferred by northern leopard frogs with a preferred range of 6.5 to 8.5
(Schlichter 1981, Vatnick et al. 1999, Wind 2002). The pH values of the TRIUM water samples ranged
from 8.1 to 8.8. The sampled pH levels were within the preferred pH range.
Although many other parameters were sampled, no other recommended levels or stated tolerance levels
for northern leopard frog or amphibians are provided in the literature.
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KEY FINDINGS
•
On August 4, 2011, northern leopard frogs were identified in Wetlands 1, 2 and 3; wood frogs were
identified in Wetlands 1, 3 and 4. On October 4, 2011, boreal chorus frogs were incidentally observed
in the immediate area.
•
Wetland 1 is a naturally occurring Class III wetland, while Wetlands 2, 3 and 4 are artificially
constructed (i.e., man-made). The wetlands appear to be functioning well for amphibian and
waterfowl/songbird habitat as well as basins for nutrient attenuation and groundwater recharge
evidenced by the presence of hydrophytic vegetation.
•
The riparian zones of all four wetlands were determined to be unhealthy due to aggregate extraction
(gravel pit) and agricultural disturbance (livestock grazing) of these areas which has resulted in a lack
of riparian fringe, surrounding land use degradation, prevalence of weedy and undesirable
herbaceous species, impeded vegetation growth and bare soils.
•
Water sample parameters (pH, hydrocarbons, alkalinity, hardness, nitrites and nitrates) from
Wetlands 2 and 3 are all either within or below the acceptable concentrations and/or limits for
northern leopard frog as stated in the literature.
•
Since northern leopard frogs are sensitive to a wide range of disturbances, their presence is
indicative of an overall functional wetland ecosystem, despite an unhealthy riparian zone.
•
Absence of amphibians from a wetland does not indicate an unhealthy wetland. The challenge with
using amphibians as indicators is discerning between natural population fluctuations and unnatural
population declines from anthropogenic sources (Welsh and Ollivier 1998).
The findings above, specifically, the presence of northern leopard frogs and juveniles, indicate that the
wetlands can and do, support breeding amphibian populations.
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8.0
REFERENCES
8.1
Personal Communications
November 2011
7926
TERA wishes to acknowledge those people identified in the Personal Communications for their
assistance in supplying information and comments incorporated into this report.
Dillabaugh, K. Senior Ecological Protection Specialist. Ministry of Environment, Land Management South,
Swift Current, Saskatchewan.
Nygren, R. Ecological Protection Specialist. Ministry of Environment, Land Management South, Melville,
Saskatchewan.
8.2
Literature Cited
Alberta Riparian Habitat Management Society. 2011. What is Riparian? Website:
http://www.cowsandfish.org/riparian/riparian.html.
Alberta Sustainable Resource Development. 2003. Status of the Northern Leopard Frog (Rana pipiens) in
Alberta: Update 2003. Alberta Sustainable Resource Development, Fish and Wildlife Division,
and Alberta Conservation Association, Wildlife Status Report No. 9 (Update 2003), Edmonton,
AB. 61 p.
Ambrose, N., G. Ehlert, K. Spicer-Rawe. 2004. Riparian Health Assessment for Lakes, Sloughs, and
Wetlands - Field Workbook. Modified from Fitch, L., B. W. Adams, and G. Hale, 2001. Riparian
Health Assessment for Streams and Small Rivers - Field Workbook. Lethbridge, Alberta. Cows
and Fish program. 90 pgs.
Arsenault, A.A. 2009. Disturbance impact thresholds: recommended land use guidelines for protection of
vertebrate species of concern in Saskatchewan. Saskatchewan Ministry of Environment. Lands
Branch - Fish and Wildlife Branch Technical Report 2009-06. 93 pp.
Cohen, M.M. 2001. Frog Decline, Frog Malformations, and a Comparison of Frog and Human Health.
American Journal of Medical Genetics 104:101-109.
Committee on the Status of Endangered Wildlife in Canada. 2009. COSEWIC assessment and update
status report on the Northern Leopard Frog Lithobates pipiens, Rocky Mountain population,
Western Boreal/Prairie populations and Eastern Populations in Canada. Website:
http://www.sararegistry.gc.ca/status/status_e.cfm.
Daszak, P., A.A. Cunningham, A.D. Hyatt. 2003. Infectious disease and amphibian population declines.
Diversity and Distributions 9:141-150.
Garrigues, P., J.E. Djomo, V. Ferrier, A. Dauta, A. Monkiedje, A. Mvondo Ze, J.F. Narbonne. 2004.
Toxicokinetics of Polycyclic Aromatic Hydrocarbons From Contaminated Sediment by the
Amphibian Larvae (Pleurodeles waltl). Polycyclic Aromatic Compounds 24: 207-214.
Greer, A.L., M. Berrill, P.J. Wilson. 2005. Five amphibian mortality events associated with ranavirus
infection in south central Ontario, Canada. Diseases of Aquatic Organisms 67:9-14.
Hanson, A. L. Swanson, D. Ewing, G. Grabas, S. Meyer, L. Ross, M. Watmough and J. Kirkby. 2008.
Wetland Ecological Functions Assessment: An Overview of Approaches. Canadian Wildlife
Service Technical Report Series No. 497. Atlantic Region. 59pp.
Kendell, K. 2002. Survey protocol for the northern leopard frog. Alberta Sustainable Resource
Development, Fish and Wildlife Division, Alberta Species at Risk Report No. 43, Edmonton, AB.
30 pp.
Long, L.L., L.S. Saylor, M.E. Soule. 1995. A pH/UV-B Synergism in Amphibians. Conservation Biology
9(5):1301-1303.
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Marquis, O., A. Millery, S. Guittonneau, C. Miaud. 2006. Toxicity of PAHs and jelly protection of eggs in
the Common frog Rana temporaria. Amphibia-Reptilia 27: 472-475.
NatureServe. 2011. NatureServe Explorer - An Online Encyclopedia of Life. Website:
http://www.natureserve.org/explorer/index.htm.
Pauli, B.D., J.A. Perrault and S.L. Money. 2000. RATL: A Database of Reptile and Amphibian Toxicology
Literature. Technical Report Series No. 357. Canadian Wildlife Service, Headquarters, Hull,
Québec, Canada..
Roberts, J.J., R.A. Wood, R.S. Haszeldine. 2011. Assessing the health risks of natural CO2 seeps in Italy.
Proceedings of the National Academy of Sciences of the United States of America
108(40):16545-16548.
Schlichter, L.C. 1981. Low pH affects the fertilization and development of Rana pipiens eggs. Canadian
Journal of Zoology 59:1693-1699.
Shakhashiri, B.Z. 2008. Chemical of the Week: Carbon Dioxide, CO2. University of Wisconsin-Madison.
Website: http://scifun.chem.wisc.edu/chemweek/pdf/carbondioxide.pdf.
Shenoy, K., B.T. Cunningham, J.W. Renfroe, P.H. Crowley. 2009. Growth and Survival of Northern
Leopard Frog (Rana pipiens) Tadpoles Exposed to Two Common Pesticides. Environmental
Toxicology and Chemistry 28(7):1469-1474.
Stabenau, E.K., D.T. Giczewski, K.Y. Maillacheruvu. 2006. Uptake and Elimination of Naphthalene from
Liver, Lung, and Muscle Tissue in the Leopard frog (Rana pipiens). Journal of Environmental
Science and Health Part A 41-1449-1461.
Stewart, R.E. and H.A. Kantrud. 1971. Classification of Natural Ponds and Lakes in the Glaciated Prairie
region. Resource Publication No. 92. U.S. Fish and Wildlife Service, Washington, D.C.
TRIUM Environmental. 2011. Assessment in SW30-5-13W2. TRIUM Environmental Inc., Cochrane, AB.
U.S. Geological Survey. 2004. Use of Amphibians as Indicators of Ecosystem Restoration Success. U.S.
Geological Survey, Davie FL. 4 p.
Vatnick, I., M.A. Brodkin, M.P. Simon, B.W. Grant, C.R. Conte, M. Gleave, R. Myers, M.M. Sadoff. 1999.
The Effects of Exposure to Mild Acidic Conditions on Adult Frogs (Rana pipiens and Rana
clamitans): Mortality Rates and pH Preferences. Journal of Herpetology 33(3):370-374.
Voordouw, M.J., D.A. Adama, B. Houston, P. Govindarajulu, J. Robinson. 2010. Prevalence of the
pathogenic chytrid fungus, Batrachochytrium dendrobatidis, in an endangered population of
northern leopard frogs, Rana pipiens. BMC Ecology 10(6). 10p.
Welsh, H.H., L.M. Ollivier. 1998. Stream Amphibians As Indicators of Ecosystem Stress: A Case Study
From California’s Redwoods. Ecological Applications 8(4):1118-1132.
Wind, E. 2002. Northern Leopard Frog (Rana pipiens) Husbandry Manual. A Report produced for the
Columbia Basin Fish and Wildlife Compensation Program, Nelson, BC, and Columbia Basin
Trust, Nakusp, BC. 65pp.
Wisconsin Department of Natural Resources. 2001. Rapid Assessment Methodology for Evaluating
Wetland Functional Values. Wisconsin Department of Natural Resources. Madison, WI.
Wray, H.E., S.E. Bayley. 2006. A Review of Indicators of Wetland Health and Function in Alberta’s Prairie,
Aspen Parkland and Boreal Dry Mixedwood Regions. Prepared for: The Water Research Users
Group, Alberta Environment, Edmonton, Alberta. 79 p.
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GIS Data and Mapping References
IHS Inc. 2011. IHS Road Segments (digital file). Calgary, AB. Available:
http://energy.ihs.com/Solutions/Regions/Canada/. Acquired: November 2011. Update Interval:
Monthly.
Iunctus Geomatics. 2010. SPOT5 2.5m Panchromatic Satellite Imagery (digital file). Lethbridge, AB.
Available: http://www.terraengine.com. Acquired: June 2011.
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APPENDIX A
PHOTOPLATES
Plate 1
Northern leopard frog observed in Wetland 1 in SW 30-5-13 W2M (August 4, 2011).
Plate 2
Northern leopard frog observed in Wetland 2 in SW 30-5-13 W2M (August 4, 2011).
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APPENDIX B
SITE CARDS
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•••DRAFT•••
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Site Card 1
WETLAND UTM (ZONE 13):
590772E 5473962N
LEGAL LOCATION
SW 30-5-13 W2M
WETLAND
CLASSIFICATION
Class III
COMMENTS
•
•
•
•
•
•
FUNCTION
•
VEGETATION
•
•
•
•
•
WILDLIFE
HYDROLOGY
•
•
natural wetland
surrounding land use is pasture
heavily disturbed by cattle –
pugging evident
alkali soils at fringe
road located to west of wetland
wetland area assessed was
approximately (2.96 ha)
proper functional conditions
observed at time of survey
dominant wetland species:
sedge sp.; common cattail;
great bulrush;
water-smartweed; duckweed
and algae sp.
riparian woody vegetation is
absent
dominant graminoid species:
foxtail barley; brome; crested
wheatgrass; wild rose; and
sage
weedy species noted: creeping
thistle; perennial sow-thistle;
and dandelion
emergent vegetation throughout
central portion
observations include northern
leopard frog, wood frog, garter
snake sp., waterfowl, shorebirds
and songbirds (killdeer, gadwall,
blue-winged teal, brown-headed
cowbird, Wilson’s phalarope,
and American coot)
isolated basin with standing
water (less than 1 m depth
present at time of survey)
Plate 1
View north providing an overview of Class III wetland
(Wetland 1) August 2011.
Plate 2
View west providing an overview of land use
surrounding Class III wetland (Wetland 1)
August 2011.
Page 22
•••DRAFT•••
Cenovus Energy Inc.
Northern Leopard Frog Survey and Wetland Assessment
November 2011
7926
Site Card 2
WETLAND UTM (ZONE 13):
LEGAL LOCATION
WETLAND
CLASSIFICATION
COMMENTS
•
•
•
•
FUNCTION
•
VEGETATION
•
•
•
•
•
•
•
•
•
HYDROLOGY
SW 30-5-13 W2M
artificially constructed
(Class IV)
•
WILDLIFE
Start:
591013E 5554544N
•
•
artificially constructed
(i.e., man-made) wetland
resulting from gravel excavation
surrounding land use is
pasture/hay land with existing
pump station infrastructure
minor cattle disturbance
wetland located immediately
north of farm house and soil
pile
wetland areas assessed was
approximately 1 ha
proper functional conditions
observed at time of survey
dominant wetland species:
common cattail, sedge sp.;
great bulrush, horsetail sp.;
western dock; and reed canary
grass
dominant tree species: willow
sp.
riparian woody vegetation fringe
(willow sp., alder and aspen)
dominant shrub species: alder;
willow sp.
dominant graminoid species:
brome; foxtail barley; crested
wheatgrass; curly-cup
gumweed; alfalfa; and western
dock
disturbance species noted:
sweet clover; and dandelion.
potentially suitable nesting
cover present
suitable spring/fall staging
areas present (open water)
observations include northern
leopard frog, mourning dove
and swallow sp.
isolated basin with standing
water (greater than 1 m depth
present at time of survey
Open water in central portion of
wetland.
Plate 1
View east providing an overview of the artificially
constructed (Class IV) wetland (Wetland 2)
August 2011.
Plate 2
View south showing an overview of the artificially
constructed (Class IV) wetland (Wetland 2)
August 2011.
Page 23
•••DRAFT•••
Cenovus Energy Inc.
Northern Leopard Frog Survey and Wetland Assessment
November 2011
7926
Site Card 3
WETLAND UTM (ZONE 13):
LEGAL LOCATION
WETLAND
CLASSIFICATION
COMMENTS
•
•
•
FUNCTION
•
VEGETATION
•
•
•
•
•
•
•
•
HYDROLOGY
SW 30-5-13 W2M
artificially constructed
(Class III)
•
WILDLIFE
Start:
590966E 5473912N
•
artificially constructed
(i.e., man-made) wetland
resulting from gravel excavation
surrounding land use is hay and
cattle pasture
fence line is located to the
northwest and landowner’s
outbuildings are located to the
east.
wetland areas assessed was
approximately 1.07 ha.
proper functional conditions
observed at time of survey
dominant wetland species:
western dock; reed canary
grass; and sedge sp.
riparian woody vegetation
distribution is sporadic
(cottonwood, willows near north
and south edge).
dominant shrub species: willow
sp.
dominant graminoid species:
wheatgrass sp.; pigweed;
brome; and sweet clover
weedy species noted: creeping
thistle; and perennial
sow-thistle.
wetland contains emergent
vegetation throughout central
portion
potentially suitable nesting
cover
observations include northern
leopard frog, garter snake sp.,
invertebrates (snail sp.),
kingbird sp., swallow sp., redwinged blackbird and muskrat.
isolated basin with standing
water (greater than 1 m present
at the time of survey).
Plate 1
View west providing an overview of artificially
constructed (Class III) wetland (Wetland 3)
August 2011.
Plate 2
View north towards sedge portion of artificially
constructed (Class III) wetland (Wetland 3)
August 2011.
Page 24
•••DRAFT•••
Cenovus Energy Inc.
Northern Leopard Frog Survey and Wetland Assessment
November 2011
7926
Site Card 4
WETLAND UTM (ZONE 13):
LEGAL LOCATION
WETLAND
CLASSIFICATION
COMMENTS
•
•
FUNCTION
•
VEGETATION
•
•
•
•
•
•
•
•
•
HYDROLOGY
SW 30-5-13 W2M
artificially constructed
(Class IV)
•
•
WILDLIFE
Start:
590862E 5473942N
•
artificially constructed
(i.e., man-made) wetland
resulting from gravel excavation
surrounding land use is pasture
extensive cattle use (pasture
not fenced from wetland);
pugging
wetland area assessed was
approximately 1.6 ha
proper functional conditions
observed at time of survey
dominant wetland species:
great bulrush; common cattail;
sedge sp.; and floating
pondweed
riparian woody vegetation
distribution is sporadic (some
willows in central portion on
west side).
dominant shrub species: willow
sp.
dominant graminoid species:
brome; foxtail barley; crested
wheatgrass; curly-cup
gumweed; and alfalfa
weedy species noted: creeping
thistle; and perennial
sow-thistle
wetland contains emergent
vegetation throughout central
portion
suitable rearing areas present
potentially suitable nesting
cover
observations include wood frog,
kingbird sp., gull sp. and
red-winged blackbird
Isolated basin with standing
water (greater than 1 m depth
present at time of survey)
Plate 1
View south providing an overview of artificially
constructed (Class IV) wetland (Wetland 4)
August 2011.
Plate 2
View south providing an overview of land use
surrounding artificially constructed (Class IV) wetland
(Wetland 4) August 2011.
Page 25