Download Appendix S.9 Culliton Creek Red Legged Frog Baseline Inventory

Appendix S.9
Culliton Creek Red Legged Frog Baseline Inventory
Red-Legged Frog Baseline
Report: Culliton Creek
Project
Bears, H. 2011. An Overview of Red-Legged Frog Presence and
Abundance, Breeding Phenology, and Habitat Values for the Proposed
Syntaris Culliton Creek Hydro-electricity Project | Zoetica Wildlife
Research Services
Page | 1
Table of Contents
1
Wildlife and Wildlife Habitat Desktop Study: Site-based Analysis of Wildlife-Project Overlaps ..................4
1.1
Overview ...............................................................................................................................................4
1.1.1
1.2
Conservation Status ......................................................................................................................4
1.2.2
Species Identification/Description ................................................................................................5
1.2.3
Biology...........................................................................................................................................5
Methods ................................................................................................................................................6
1.3.1
Habitat Values ...............................................................................................................................6
1.3.2
Presence and Abundance Surveys (30 May, 03 June, 2011).........................................................7
Results and Discussion ..................................................................................................................................8
2.1
3
Background Species Information ..........................................................................................................4
1.2.1
1.3
2
Objectives......................................................................................................................................4
Baseline Lentic Habitat Conditions........................................................................................................8
2.1.1
Wetland Complex..........................................................................................................................8
2.1.2
Seepage Zone ..............................................................................................................................12
2.1.3
Breeding Phenology ....................................................................................................................13
2.1.4
Habitat Values .............................................................................................................................14
2.1.5
Incidental Observations ..............................................................................................................15
General Conclusions....................................................................................................................................18
Literature Cited ...................................................................................................................................................19
4
Limitations and Constraints ........................................................................................................................20
5
Appendix A ..................................................................................................................................................20
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EXECUTIVE SUMMARY
Northern Red-legged frog surveys were conducted from 30 May to 03 June, 2011. All
habitats that could host red-legged frogs were examined on foot. Areas of potentially
suitable habitat were subjected to surveys for adults and egg masses and habitat was
described and assessed. Three main locations where breeding could be found were: a
pond/wetland complex near the southwestern end of the project area (Ponds 1 and 2), a
seepage area along the access road (Zone 1), and a mature forested area along the base of
Culliton Creek to the east of Highway 99 (Zone 2). The wetland complex was found to host a
large number of breeding females (approximately 29, as estimated from 29 egg masses
found). Application of similar methods in future may be used to monitor for long-term
changes in abundance relative to these results.
Survival rates of are expected to be relatively high at the wetland location (Ponds 1 and 2)
as there is ample aquatic food, low risk of stranding due to drying (deep ponds), and low
predation risk. Due to unsuitable features surrounding the wetland complex on 3 sides,
dispersing red-legged frogs likely move in a northward direction, crossing the access road
and likely moving eastwards along riparian habitat adjacent to Culliton Creek. The seepage
area (Zone 1) was found to host fewer breeding frogs; however, tadpoles may be stranded
due to water evaporation from these pools in dry years. No egg masses or tadpoles were
found in the third seepage area (Zone 2); this zone is still considered moderately suitable as
terrestrial and winter habitat for adults, however, due to highly shaded, mature forest, moist
conditions. Red-legged frogs were found to oviposit egg masses from late May to late June,
and tadpoles emerged and metamorphosed from late June to late October.
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1 Wildlife and Wildlife Habitat Desktop Study: Site-based
Analysis of Wildlife-Project Overlaps
1.1 Overview
Zoetica Wildlife Research conducted a baseline assessment of Northern red-legged frogs
(Rana aurora), a species at risk (SAR) associated with the proposed Culliton Creek Hydroelectric Project. The Culliton Creek Project is a small hydro-electric project (15 MW)
proposed by Culliton Creek Power Ltd. Partnership. The project is located approximately 20
km north of Squamish, BC (Figure 1.1-1). Incidental observations of adult northern redlegged frogs by Cascade Environmental during prior inventory work necessitated an
inventory focused on documenting the use of habitat within the project area by this species.
This report presents results of a survey conducted within the project area from 30 May - 03
June, 2011; this survey documented key red-legged frog habitat features, evidence and
timing of breeding, and relative abundance. These data may aid in decision making
processes regarding appropriate mitigation, management, compensation, and/or long-term
monitoring plans.
1.1.1 Objectives
The main objectives of this baseline report were to:
1)
Identify suitable lentic (i.e., water body) habitat features within or near the
project area as well as habitat that could support terrestrial migration between various
lentic features, or between lentic and wintering habitats.
2)
Discuss the evidence of breeding within lentic features (detection/nondetection of breeding, relative abundance where estimates are possible using egg
mass surveys); and,
3)
Determine the approximate breeding phenology (timing of breeding) for key
reproductive life-history stages of red-legged frogs in the study area.
Additional incidental wildlife observations in the area are also reported. Information
presented in this report will provide a measure of presence and abundance against which
future monitoring data can be compared.
1.2 Background Species Information
1.2.1 Conservation Status
Due to their limited range, particularly within BC and Canada in general, northern red-legged
frogs are a species of conservation concern. They are provincially Blue-listed by the BC
Conservation Data Centre, and are on Schedule 1 of the Federal Species at Risk Act
(SARA) registry. Habitat degradation, loss, and fragmentation are major factors affecting
red-legged frogs within their BC range (Ovaska and Sopuck 2004). Red-legged frogs are
rated as a Priority 1 species under Goal 2 of the BC Conservation Framework, which
recognizes the need for pre-emptive action to prevent declines of the species.
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Transmission Line
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1,000
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Squamish
2,000
Metres
Coordinate System: NAD 1983 UTM Zone 10N
485000
© Department of Natural Resources Canada. All rights reserved.
490000
November 15 2011
495000
ZW-CL-001
Figure 1.1-1. Location of
Culliton Creek Project
1.2.2 Species Identification/Description
Adult Northern red-legged frogs are approximately 4.4 to 7.6 cm long, from snout to vent
(rump). Their colour varies from reddish-brown, gray or olive with black flecks and spots on
the back and sides and dark banding on the top of the legs. This species also has a dark
mask on its head and a stripe extending from the shoulder to the front of the upper jaw.
When this species is flipped upside down, the red underside of its hind legs can be seen
(Photo 1.2-1).
Photo 1.2-1 Photographs of Northern red-legged frog adults from the Culliton Creek study
area.
Tadpoles are brown, with small dark spots. The lower section of the body of the tadpole
contains some creamy white coloured flecks with small spots. Rows of light spots may also
be evident along the back, from behind the eyes towards the tail. Egg masses are laid in
masses of 530 - 830 eggs (ranging from 100 - 1,100 eggs) in a large gelatinous cluster that
is attached to vegetation beneath the water. Further images of tadpoles and egg masses
can be seen within Table 1.2-1.
1.2.3 Biology
Northern red-legged frogs extend from the coastal lowlands of southwestern BC to
Washington, Oregon, and northern California. Within BC, the red-legged frog is confined to
the southwestern part of the province, including Vancouver Island and the Gulf Islands. On
the mainland, it occurs west of the Coast Mountains in the Fraser valley and adjacent to the
Strait of Georgia. Its northern limit may occur as far north as Kingcome Inlet (the latitude of
ca. the north end of Vancouver Island) (Waye 1999).
During the breeding season, Northern red-legged frogs are found near permanent waters,
including stream pools, marshes, ponds, and other slow moving bodies of water. Breeding
occurs in permanent water where eggs are attached to submerged vegetation. After
breeding, adults may live in damp woods and meadows relatively far from water. Redlegged frog tadpoles are herbivorous, while adults are carnivorous, mainly feeding on
invertebrates. Adults use small mammal burrows and moist leaf litter in dense riparian
vegetation (vegetation alongside water bodies) up to ≥26 meters from water, and
desiccation (dried) cracks in dry pond bottoms as refuge and aestivation sites (Rathbun et
al. 1993; Alvarez 2004). Table 1.2-1 shows the key life history stages, photographs of each
stage, and the general seasons within which each stage is expected to occur.
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Table 1.2-1 Key life-history phases, associated the general seasonal timing of phases, and habitat use for redlegged frogs (Photos Credits: H. Bears (egg mass and adult), James Bettaso, Amber F. Palmeri-Miles
(tadpoles and toadlets) B=Breeding; L=Living.
Egg Laying: (3 mm) Lay
eggs in February to April
(when water temp. is 6-7 C).
Hatchlings and Tadpoles:
(4-6 mm and 6-35 mm).
Eggs hatch to produce
tadpoles in late spring to
summer.
X
Adult Living/Breeding:
(30-100 mm) Adults breed early
in the spring and active until fall.
Inactive during coldest periods
of winter.
B
Deep
Pond
X
Froglets: (18-40 mm):
Tadpoles metamorphose
into to small froglets in
the late summer.
X
B
X
L
Marsh
Shallow
Pond
X
Forest and
Logs
L
Edges of Large
Streams
Edges of
Medium
Streams
L
X
L
1.3 Methods
1.3.1 Habitat Values
A 4-class rating system for mapping breeding habitat at either 1:50,000 or 1:20,000 is
suggested by RISC (1999). However, there are problems with developing a standardized
wildlife habitat suitability map for the red-legged frog because Provincial Benchmarks have
not been described and attributes available in forest cover or TRIM data sets do not capture
the habitat attributes required by this species during the breeding season. Further, suitable
breeding habitat can occur in ditches along a roadside, in rock crevasses, floodplains, or in
small forest wetlands not visible on aerial photographs (Wind 2002), and which may be
missed when doing a site visit. Therefore, a general, qualitatively derived 3-class habitat
map (Low, Moderate, and High Suitability) was created from map information and groundbased field work, focusing on areas where water may pool for breeding, or where the habitat
may be sufficiently moist to host the species during its terrestrial phase and during migration
between lentic and/or wintering sites. No assumptions of nil (unsuitable) habitat were made,
as this survey represented a snapshot in time, with particular weather and moisture
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conditions. Areas not assigned to a habitat class were either not assessed, or could not be
assessed for their value over the season given time-dependent weather conditions.
After the area was covered on foot, polygons were digitally drawn from field observations
and then digitized. Each water body identified as suitable is described in this report and
photographed. Additional measurements were taken from lentic and terrestrial transect sites
to aid in the determination of polygon classes and locations (Table 1.4-1). These data are
mentioned in the report where relevant, and are included in Appendix A. A detailed analysis
of the vegetation data was not performed, but is possible to infer when determining impacts
on habitat during the monitoring stage.
Table 1.4-1 Habitat measurements taken for consideration in evaluating the suitability of
lentic and terrestrial sites for red-legged frogs (measures included in Appendix A).
Lentic
Water temperature
Dominant vegetation
Water depth at edge
Amount of algae in water
Terrestrial
Elevation, Slope, Aspect
Intermittent water
Inorganic ground cover (% cover classes)
Leaf Litter
Moss cover (% cover classes)
Herb cover (% cover classes)
Shrubs (% cover classes)
Canopy cover (% Cover)
Dominant tree species
Coarse woody debris (CWD) prevalence and
class
Dominant tree species
Mean dbh
1.3.2 Presence and Abundance Surveys (30 May, 03 June, 2011)
From 30 May to 03 June, 2011, egg mass surveys were conducted to assess presence of
breeding activity of red-legged frogs breeding within lentic features within the potential zone
of influence of the project. The advantages of using egg mass surveys were that:
a) Females lay a single egg mass each year; hence, egg mass counts provide a
relatively accurate assessment of the number of breeding females associated with a
lentic feature;
b) Egg mass surveys can be used for monitoring and research programs to estimate
changes in abundance in lentic features over time.
The survey was done in two main phases: A general scoping survey for suitable habitat, and
then a more detailed survey for breeding evidence within the suitable habitat. In the first
phase, a topographic map was used to determine areas where water might pool. All
potential breeding areas were visited by observers on foot. Water bodies were searched for
egg masses by wildlife biologists familiar with this species. If a lentic feature was thought to
have a low likelihood of providing breeding habitat, less time was spent searching the
feature for egg masses. Likewise, areas suspected to provide a higher likelihood of breeding
success were searched more diligently. Where one or more egg mass was discovered, the
second survey phase, consisting of detailed egg mass counts, was initiated.
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A double-observer technique was used to estimate egg mass abundance within a lentic
feature once presence was established (Cook and Jacobson 1979, Nichols et al. 2000).
Observer 1 counted and pointed out egg masses to Observer 2. Observer 2 recorded what
Observer 1 reported, but also wrote down egg masses that Observer 1 missed or counted
twice. Participants then switched roles halfway around the lentic feature, and the largest
count, discarding double counts, was used. Counts were conducted twice over the survey
period with the goal of recording the maximum number of egg masses present within a pond
on a single trip. Double-observer techniques could not correct for other biases such as those
caused by weather, turbidity, or inaccessibility of a portion of a feature to an observer.
The interior periphery of all suitable water bodies were surveyed for egg masses in May
2011. Surveys were conducted on foot using chest waders, but in deeper ponds and
wetlands surveys could not be conducted on foot and inflatable rafts were used. Each
observer paddled around edges and other potential attachment sites (e.g., trees blown into
water) using the double observer method. Egg masses were often visible from above the
water, but the observer was able to clearly count all masses with their head submerged.
When egg masses (or tadpoles at later dates) were found, dates were recorded in order to
construct an approximate site-specific reproductive phenology schedule to aid in the
development of temporal mitigation strategies.
2 Results and Discussion
2.1 Baseline Lentic Habitat Conditions
There were two major locations of interest that could support breeding red-legged frogs in
the Culliton Creek study area:
1) A wetland complex, consisting of a large (Pond 1; Figure 2.1-1) and small (Pond 2;
Figure 2.1-1) pond to the immediate south of the base of Culliton Creek, along
Highway 99; and
2) A seepage area (Zone 1; Figure 2.1-1) along the edge of the access road where
standing water pooled and could be of sufficient depth to support eggs.
Descriptions of these locations and evidence and quantification (when available) are
discussed for each of these locations in the following sections.
2.1.1 Wetland Complex
Pond 1
Pond 1 is the larger of the two lentic features comprising the wetland system (Figure 2.1-1).
Pond 1 is 157 m x 67 m, or 10, 519 m 2 (0.01 km2). The dominant vegetation species on
each side of the pond are summarized in Table 2.1-1.
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Table 2.1-1 Dominant aquatic/lentic (edge) and terrestrial vegetation species and features
surrounding pond 1.
Shore
Side
East
Type
Dominant Species/Feature
Aquatic
CWD in water
-
Labrador tea
Rhododendron groenlandicum
Red alder
Alnus rubra
Hardhack
Spiraea douglasii
Common cattail
Typha latifolia
CWD in water
-
Hardhack
Spiraea douglasii
Labrador tea
Rhododendron groenlandicum
Common cattail
Typha latifolia
Mossy CWD in water
-
Common cattail
Typha latifolia
Mossy CWD in water
-
Yellow pond-lily
Nuphar sp.
Red alder hanging/submerged
Alnus rubra
Willow spp. hanging/submerged
Salix sp.
Skunk cabbage
Lysichiton americanus
Labrador tea
Rhododendron groenlandicum
Terrestrial
North
Aquatic
Terrestrial
South
West
Aquatic
Aquatic
Terrestrial
Scientific Name
A series of four water depth measurements were taken 1 m from the shore at each side of
this pond; the average offshore depth was 36.5 cm. The depth of the pond at the centre
could not be measured as it was deeper than 3 m. The average water temperature
measured was 14.7oC (taken 30 cm below the surface at 3 locations). The water was
relatively clear and did not contain a floating algae cover; however, submerged coarse
woody debris was heavily lined with algae. This pond was rated as Class 1 breeding habitat
and ample evidence of breeding was found.
Pond 2
Pond 2 is the smaller of the two lentic features comprising the wetland system (Figure 2.11). Pond 2 is approximately 133 m x 26 m, or 3, 458 m 2 (0.004 km2). The dominant lentic
and terrestrial vegetation on the outer edge of this pond varied around the perimeter. The
dominant species on each side of the pond are summarized in Table 2.1-2 below.
Table 2.1-2 Dominant aquatic/lentic (edge) and terrestrial vegetation and features
surrounding pond 2.
Shore
Type
Species
Scientific Name
East
Aquatic
Skunk cabbage
Lysichiton americanus
Yellow pond-lily
Nuphar sp.
CWD in water
-
Hardhack
Spiraea douglasii
Terrestrial
Page | 9
Willow ssp.
Salix sp.
Red-osier dogwood
Cornus stolonifera
Salal
Gaultheria shallon
Thimbleberry
Rubus parviflorus
Labrador tea
Rhododendron groenlandicum
North
Aquatic
Common cattail
Typha latifolia
South
Terrestrial
Large mossy boulders
-
West
Aquatic
Common cattails
Typha latifolia
Yellow pond-lily
NupharI sp.
Horsetail
Equisetum sp.
Hardhack
Spiraea douglasii
Skunk cabbage
Lysichiton americanus
Willow spp.
Salix sp.
CWD
-
Terrestrial
A series of four water depth measurements were taken 1 m from the shore at each side of
this pond; the average offshore depth was 61.3 cm. The depth of the pond at the centre
could not be measured as it was deeper than 3 m. The average water temperature
measured was 15oC (taken 30 cm below the surface at 3 locations). The water was
relatively clear and did not contain a floating algae cover; however, submerged coarse
woody debris in this pond was heavily lined with algae. This pond was rated as Class 1
breeding habitat due to optimal habitat conditions for the species and ample evidence of
breeding. Photographs of these ponds are shown in Photo 2.1-1.
Photo 2.1-1 Pond 1 as photographed from the elevated bluff along the east side facing
Highway 99 (left) and Pond 2 photographed from the north end of the pond.
Breeding Evidence in Wetland Complex (Ponds 1 and 2)
The wetland complex contained many egg masses, and is likely the main “source”
population for red-legged frogs for Culliton Creek. The wetland complex also represents
stable bodies of water that will not dry up prior to tadpole development and metamorphosis
Page | 10
in drier years. As each egg mass is deposited by one female, the minimum adult breeding
population within the wetland complex (Pond 1 and 2) was estimated (Table 2.1-3). This
complex was estimated to hosts at least 29 breeding females in total. Assuming a sex ration
of 1:1, at least 58 adult red-legged frogs (29 F: 29 M) breed within these features. As young
adult females (< 2-3 years of age) do not yet breed, these values likely under-estimate the
total female population, representing only the population of adult females of a breeding age.
The south and west shores contained the most adult frogs and egg masses relative to the
other shores. Most egg masses were attached to stems of aquatic vegetation, or to
underwater branches attached to windblown trees in the ponds.
Table 2.1-3 The number of egg masses found in each of the lentic features (pond 1 and 2)
within the wetland complex, along with the estimated number of breeding females (based on
1 female per egg mass) and the estimated number of males and females (assuming a 1:1
sex-ratio).
Wetland Complex Feature
Number
Large Wetland (Pond 1)
19 (Egg masses)
Small Wetland (Pond 2)
10 (Egg masses)
Total (Est. Females)
29
Total (Est. Males and Females)
58
Photographs of an adult red-legged frog and egg mass taken from this wetland complex are
included in Photo 2.1-2.
Photo 2.1-2 Red-legged frog adult (left) and egg mass (right) taken from the wetland
complex on 02 June, 2011.
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2.1.2 Seepage Zone
A seepage zone (zone 1) created a series of pockets of standing water and pools,
particularly alongside the edge of the access road (Figure 2.1-1). The water temperature
within these lentic pockets ranged from 7.5 to 13 oC. Sites in this area could host red-legged
frog eggs; however, this area could occasionally act as an ecological trap, drawing adults to
deposit eggs, but drying up before tadpoles reach metamorphosis. The productivity within
this area is likely to vary between years based on rainfall. This area beginning at UTM 10 U
0490900 5525540 and extending to 10 U 0495780 5524975 was classified as Class 2
habitat; it is considered to be of moderate rather than high value for breeding, as lower
densities of breeding red-legged frogs could be sustained compared to the wetland
complex, and some features may dry up prior to production of emerging young of the year
frogs. As many small lentic features exist that may vary among years, the entire area was
broadly labelled as part of the same Class 2 habitat network. Dominant vegetation around
these features included ferns, herbaceous plants and shrubs, coarse woody debris and
wind-blown trees. A photograph of featured within this zone is shown in Photo 2.1-3.
Photo 2.1-3 Small pockets of standing water within seepage area thought to provide
breeding habitat for red-legged frogs.
A second seepage zone (Zone 2), centred around UTM 10 U 0488580 05524960 was
detected near the lower elevation section of Culliton Creek was identified with some
potential pools within which breeding may be possible in certain years (Figure 2.1-1).
However, very few pools suitable for egg deposition were found in this zone in 2011, nor
was any evidence of egg masses or tadpoles. This location, which was moist and had ample
overhead cover, moss on the ground, and structural heterogeneity, may serve as valuable
terrestrial and wintering habitat, potentially as part of a travel corridor for frogs en route
during dispersal from the lower wetland complex to another suitable breeding habitat
(potentially the upper seepage area).
Breeding Evidence in Seepage Zone
No egg masses were detected within either zone 1 or 2 during the survey discussed in the
present report. Egg masses in these zones may have been placed in difficult to detect
locations (e.g., under submerged root networks of downed trees). On 20 July, 2011, K.
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ZW-CL-002
November 17 2011
Figure 2.1-1. Red-legged Frog Survey Data and Habitat Suitability
492000
490000
488000
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© Department of Natural Resources Canada. All rights reserved.
Coordinate System: NAD 1983 UTM Zone 10N
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Goodearle and Charlie George (Tsleil Waututh First Nation) noticed tadpoles within two of
the lentic features in seepage zone 1 (UTM 10 U 0490367 5525243 and 0490349 5525382),
along with two adult frogs (Photo 2.1-4; 10 U 0490507 5525338 and 0490317 5525220)
(Figure 2.1-1). Tadpole densities appeared low, but precise quantification was not
attempted, as the observations were incidental during vegetation surveys.
Photo 2.1-4 Red-legged frog adult (left) and tadpoles (right) taken in the seepage zone on
20 July, 2011.
It is important to note that water at this location was shallow. Tadpoles require 3-4 months to
metamorphose, and water may not remain in the pool shown in Photo 2.1-4 for a sufficient
length of time to allow tadpoles to survive a full metamorphose. Furthermore, the shallow
depth of the seepage pools will render tadpoles within them more susceptible to predation.
As with other anurans, the survival rates of tadpoles to successful metamorphosis into
froglets is much lower than any other stage, and is estimated at < 5% for this species (Licht
1974). Therefore, this location may support few reproductive attempts that actually succeed
in production of frogs, particularly during dry years. It is suspected that this site supports a
small population of red-legged frogs, but that it is probably a sink population that is
supported by dispersers from a more productive area, possibly the wetland complex.
2.1.3 Breeding Phenology
Phenology observations collected within the study area are summarized in Table 2.1-4.
These data were used along with general maturation schedules that state that eggs hatch 45 weeks after egg masses are laid (Brown 1975) and tadpole hatchlings take 3-4 months to
fully metamorphose into frogs that can then take on a terrestrial lifestyle (Licht 1974; Brown
1975). Using empirical data in Table 2.1-4 and published information, a reproductive
phenology schedule was created (Table 2.1-5).
Table 2.1-4 Observations used to create an estimated, local phenology schedule for basic
life history traits of red-legged frogs.
Observation
Egg Masses
Page | 13
Date(s)
01 June – 03 June
Location (UTM 10U)
Wetland Complex
(0488471 5524084)
Observer(s)
Heather Bears
Amanda Klein
12 June
Wetland Complex
(0488471 5524084)
Heather Bears
Tadpoles
20-July
Pockets of suitable habitat
within seepage zone along
access road with tadpoles
present
 0490367 5525243
 0490349 5525382
Keven Goodearle
Charlie George
Toadlets
Adults
N/A
30 May – 03 June,
20 July
None Observed
Adults seen within both ponds
of the wetland complex and at 2
locations within seepage area
along the access road:
 0490507 5525338
 0490317 5525220
N/A
Heather Bears
Keven Goodearle
Amanda Klein
Charlie George (Tsleil
Waututh First Nation)
Table 2.1-5 Phenology schedule for Culliton Creek area based on data collected in 2011
and published reports on development times from southern BC. The shaded area
represents the anticipated core time periods, but a smaller amount of the population may
breed slightly earlier or later, as the species is not completely synchronous with its breeding.
Life History Stage
Egg Masses
Tadpoles Emerge
Metamorphosis
New Adults
May
June
July
August
Sept
October
2.1.4 Habitat Values
A general habitat suitability map was created to aid in current or future spatial mitigation,
mitigation and/or salvaging efforts (Figure 2.1-1). The map highlights habitat of high quality
for the seasonal period examined (late spring/summer breeding period). The highest quality
habitat (Class 1; high quality) was assigned to the wetland complex due to it having highly
suitable habitat characteristics for this species, demonstrating a proven high use by
breeding individuals (egg masses), and hosting a relatively large number of adults around its
periphery (*note that egg mass locations are marked as a point in each pond within the
wetland complex, but that they were distributed around the edge of the pond and attached to
trees that had fallen into the pond; i.e. these points just show presence and relative numbers
in each pond). This complex supported many egg masses that are not at risk of being
stranded above water during a dry year. The deep water and structural complexity of ponds
1 and 2 will also likely reduce predation of tadpoles.
The lentic habitat features associated with the seepage area along the access road along
with other small patches where water was found to pool in areas, were assigned a habitat
suitability Class of 2 (moderate quality) due to its value as breeding and potential
overwintering habitat. It was not assigned a Class 1 status due to the recognition that the
area cannot likely support a high number of productive red-legged frogs, nor are many egg
masses expected to develop into frogs due to desiccation and predation risks.
Page | 14
Terrestrial habitat was assigned a low habitat value (Class 3) if it provided enough
vegetation cover to act as a travel corridor at some point in the season between patches
suitable lentic features or to and from a breeding area to an overwintering area. Class 3
habitat may not be important for breeding or overwintering, but it may be highly important
habitat linking these features, even if the habitat is only used once per year during a
migratory event. Habitat associated with streams and creeks (riparian habitat) is slightly
more valuable to red-legged frogs during the terrestrial life history phases.
It is noted that dispersal habitat (movement corridors) in the area appears limiting for this
species. The wetland complex is bounded on the west side by the highway, on the east side
by steep cliffs, and on the south side by cliffs and rocky bluff habitat. Red-legged frogs
would be unable or highly unlikely to disperse in these 3 directions, and would be required to
move northward through narrow, marginal habitat in some locations when dispersing. Frogs
dispersing from the wetland complex may, move from the north end of the wetland complex
northward towards the Class 2 habitat indicated along the bottom section of Culliton Creek,
where moist forest and riparian areas provide suitable terrestrial and winter habitat. They
may migrate far distances between aquatic breeding sites, upland summer foraging areas
(hundreds to thousands of metres; Hayes et al. 2002), and overwintering areas Individuals
dispersing from the wetland complex in this manner must cross the access road (see
predicted dispersal movement arrow in Figure 2.1-1).
Dispersion may also occur from the wetland complex and along a small tributary, towards
the location of the historic adult observation made by Cascade Environmental (Figure 2.1-1;
this observation provided initial evidence of presence and necessitated this more detailed
baseline study. However, clearing of the transmission line and other activities makes
portions of this potential travel corridor of low quality. Further, during the inventory period
used in this study, there were few areas along this tributary where breeding would have
been successful prior to breeding pools drying; however, this may vary between years and a
small portion of this tributary was assigned a moderate (Class 2) habitat value due to its
potential as overwinter habitat value, its usefulness as a travel corridor stopover (very little
moist habitat is otherwise available between the wetland complex and Culliton Creek), and
potential habitat pockets with breeding value during wet years.
The habitat indicated as Class 2 along the western end of Culliton creek, to the immediate
east of Highway 99, has many crevices and burrows for shelter, along with a great deal of
moss and ground cover, ample moisture, insect availability, and mature forest structure. It is
possible that individuals that disperse to this area could move eastward and up in elevation
along the riparian corridor towards the seepage area to breed the following spring.
2.1.5 Incidental Observations
Additional notable observations of other wildlife were also made during the survey (Table
2.1-6). Mapped locations of these observations are also provided in Figure 2.1-2.
Page | 15
Table
2.1-6 A table of incidental wildlife observations (excluding songbirds) and associated
locations collected during the red-legged frog survey in 2011.
Incidental Observations
UTM (10U)
Observation
X proj.
Y proj.
0488432
5524578
Mule deer (Odocoileus hemionus) hair
1 clump
0488493
5525172
Northern Alligator Lizard (Elgaria coerulea)
1
0488528
5524450
Northern Alligator Lizard (Photo 2.1-3)
1
June 1, 2011
June 1, 2011
June 1, 2011
0488621
0488573
0488543
5523622
5523753
5523718
1
1
6 piles
June 1, 2011
June 1, 2011
June 1, 2011
June 2, 2011
0488560
0488501
0489978
5523778
5523746
5525102
Garter snake (Thamnophis spp.)
Garter snake
Mountain goat (Oreamnos americanus) trail and
scat behind pond 1 and 2 of wetland complex.
One pile less than 2 weeks old. Scat from a
nanny and kid. Trail leading up rock edge. Goat
prints also present (Photo 2.1-4).
Black bear (Ursus americanus) scat
Black bear tree markings
Mule deer hair
Erosion area from 490 m down to Culliton Creek
and elevational extent of NRLF range
June 2, 2011
0490021
Black Bear tree marking along access roadfresh within a week (Photo 2.1-5).
>3
June 2, 2011
June 2, 2011
0490849
0489087
5525530
5524706
2 pairs
2
June 2, 2011
0489716
5524795
Harlequin duck in Culliton Creek (Photo 2.1-6)
Cougar (Felis concolor) print on forestry spur
road
Mountain goat hair on forestry spur road
June 2, 2011
June 3, 2011
0489114
0488560
5524656
5523774
Mountain goat hair on forestry spur road
Oregon forest snail (Allogona townsendiana;
red- listed in BC) on log near large wetland
1
1
June 3, 2011
496161
5630675
Mountain goat scat
1 pile
Date
May 30,
2011
May 30,
2011
June 1, 2011
Page | 16
5525113
Amount
1
2
NA
>4
486000
488000
490000
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© Department of Natural Resources Canada. All rights reserved.
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Coordinate System: NAD 1983 UTM Zone 10N
490000
492000
ZW-CL-003
November 16 2011
Figure 2.1-2. Incidental Wildlife Observations(Excluding
Songbirds) and Associated LocationsCollected During
the Red-legged Frog Survey in 2011.
Photo 2.1-3 Northern alligator lizard caught on a south facing aspect on the north shore and near the base
of Culliton Creek.
Photo 2.1-4 Evidence of mountain goat use of the bluff behind the wetland complex (Left: Scat, Right: Prints)
Photo 2.1-5 Fresh bear markings made along proposed access road.
Page | 17
Figure 2.1-6. Harlequin duck (2 pairs) seen below the proposed upper intake location on Culliton Creek.
3 General Conclusions
This inventory baseline showed that red-legged frogs do indeed breed in the Culliton Creek
project area. Breeding was confirmed within two locations. A wetland complex was found to
host a large number of breeding females (approximately 29) and egg masses. Survival rates
of tadpoles metamorphosing into adults are expected to be relatively high at this location as
there is ample aquatic food, no risk of stranding due to drying (deep ponds), and low
predation risk. It would be possible to perform similar monitoring methods in subsequent
years to track potential effects of the project on red-legged frog abundance at this high
quality habitat. The second location was a seepage area (zone 1) with small pools of water
found to host smaller numbers of breeding frogs; however, seasonal drying may threaten to
leave tadpoles stranded in dry years. A third area (seepage area mapped as zone 2) may
also provide some habitat in future years, but few suitable pools for breeding were found in
2011 in this area, and no egg masses or tadpoles were found. In general, it is expected that
the wetland complex is the dominant source of breeding habitat in the study area and likely
drives local population numbers.
The moderate quality habitat in zone 1 and zone 2 is considered moderately suitable as
terrestrial and winter habitat for adults. Northern red-legged frogs have oviposited egg
masses between late May and late June, and tadpoles are expected to emerge and
Page | 18
metamorphose into adults between late June and late October. Due to unsuitable features
surrounding the wetland complex on 3 sides, dispersing frogs would need to move in a
northern direction, crossing the access road and likely moving eastwards along riparian
habitat adjacent to Culliton Creek.
Literature Cited
Alvarez, J.A. Alvarez, 2004. Rana aurora draytonii microhabitat (California red-legged frog).
Herpetelogoical
Review 35(2), pp. 162-163.
Cook, R.D., and J.O. Jacobson. 1979. A design for estimating visibility bias in aerial
surveys. Biometrics
35:735-742.
Brown, H.A. 1975. Reproduction and development of the Red-legged frog, Rana aurora, in
Northwestern
Washington. Northwest Sci. 49(4):241–252.
Hayes, M.P., C.A. Pearl and C.J. Rombough. 2002. Natural history notes: Rana aurora
aurora (northern redlegged frog). Movement. Herpetological Review 32:35–36.
Licht, L.E. 1974. Survival of embryos, tadpoles, and adults of the frogs Rana aurora aurora
and Rana pretiosa
pretiosa sympatric in southwestern British Columbia. Can. J. Zool. 52:613–627.
Nichols, J.D., J.E. Hines, J.R. Sauer, F. Fallon, J. Fallon, and P.J. Heglund. 2000. A doubleobserver approach for estimating detection probability and abundance from avian
point counts. The Auk 117:393-408.
Nichols, J.D., J.E. Hines, J.R. Sauer, F. Fallon, J. Fallon, and P.J. Heglund. 2000. A doubleobserver approach for estimating detection probability and abundance from avian
point counts. The Auk 117:393-408.
Rathbun, G. B., M. R. Jennings, T. G. Murphey, and N. R. Siepel. 1993. Status and ecology
of sensitive
aquatic vertebrates in lower San Simeon and Pico Creeks, San Luis Obispo County,
California. Unpublished Report, National Ecology Research Center, Piedras Blancas
Research Station, San Simeon, California, under Cooperative Agreement (14-160009-91-1909). 103 pp.
RISC. 1998a. Inventory methods for pond-breeding amphibians and painted turtle.
Standards for
Components of British Columbia’s Biodiversity No. 37 [Forms]. Prepared by the
Ministry of Environment, Lands and Parks Resources inventory Branch for the
Terrestrial Ecosystem Task Force Resources Inventory Committee, March 13 1998.
Version 2.0.
Waye, H. 1999. Status report on the northern red-legged frog, Rana aurora, in Canada.
Report
prepared for the Committee on the Status of Endangered Wildlife in Canada. Ottawa,
Ont.
Wind, E. 2003. Aquatic-breeding Amphibian Monitoring Program: Analysis of Small Wetland
Habitats on
Vancouver Island. Unpublished Annual Progress Report 2002 prepared for
Weyerhaeuser BC Coastal Group, Nanaimo, BC. 29 p.
Page | 19
4 Limitations and Constraints
Zoetica Wildlife Research Services recognizes the following factors within this baseline,
which may impact results herein:

Survey length and the season within which the survey was conducted may influence
results. Only habitat that could be visited on the ground within the survey period could
be assessed for suitability. Furthermore, surveys occurred during the period of egg
mass presence. Additional occupied areas may have been found with a detailed
inventory for tadpoles, particularly where egg masses may have been cryptic. For this
reason, opportunities for adaptive management, and integration of new information
should be included in monitoring plans.
5 Appendix A
Page | 20