Assessment of red-legged frog (Rana aurora)
and coastal tailed frog (Ascaphus truei)
conservation values on Mt. Elphinstone
Final Report
to
Sunshine Coast Conservation Association
Box 1969
Sechelt, BC
V0N 3A0
Prepared by
Box 612 (1021 Raven Dr.)
Squamish, B.C.
V0N 3G0
Contact: Linda Dupuis
Phone: (604)898-4770, Fax: (604)898-4742
l.dupuis@telus.net
August 30, 2004
1. OVERVIEW
The forestlands on south facing mid-slope of Mount Elphinstone (Fig. 1) are an area of
concern to many citizens of the Sunshine Coast, because the 1600-ha area is relatively
free of landscape fragmentation and habitat degradation. Furthermore, mature forests are
predominant in the area, and represent prime old-growth recruitment sites. In a
predictive modeling exercise by the Nature Conservancy of Canada, Mount Elphinstone
rated as a good candidate for conservation. Due to its vicinity to Vancouver (40km,
northwest), the area is subject to intense pressures from developers and resource
managers. Species at risk, critical habitats, and endangered ecosystems have been
identified, and the Sunshine Coast Conservation Society is currently compiling a
comprehensive inventory strategy for these elements of concern. Linda Dupuis (dba
Ascaphus Consulting) was retained to assess distribution patterns and critical habitats of
two amphibians of concern (the blue-listed red-legged frog (Rana aurora) and the coastal
tailed frog (Ascaphus truei), and recommend conservation and management measures.
2. BACKGROUND INFORMATION
Coastal tailed frog
Tailed frogs occur in mountain and fjord-side tributaries fed by contributing basin areas
of about 50 km2 or less (Dupuis and Friele 2003). Breeding reaches are typically less
than 10 km2 in area. Creeks draining catchments of this size typically display cascade or
step-pool bedforms with locked boulder steps and pebble/cobble substrates. The geologic
literature indicates that the disturbance regime of a particular channel is related to basin
morphology (see DeScalley et al. 2001), such as ruggedness (overall basin steepness) and
relief. Geologic processes affecting catchments <10 km2 in area include floods, sediment
pulses, debris flows, rockfall/avalanche and snow avalanche activity. Recent work has
shown that tailed frog populations respond to both habitat and watershed-level
parameters, and that the species thrives best in creeks with a moderate disturbance regime
(Dupuis and Friele 2003; Frid et al. 2003). Table 1 summarizes the range of site and
watershed level habitat parameters that contribute to optimal tailed frog breeding habitat;
the information is based on the work of Dupuis and Friele (2003).
Table 1: Site and watershed level parameters defining optimal tailed frog habitat
Habitat Parameter
Flow
Basin Area (km2)*
Watershed Steepness (%)*
Reach slope (%)
Disturbance Regime
Substrate Embeddedness
Bankfull width
Water temp (°C)
* map-derived variables
Ideal Range
Perennial
0.3 - 10
31-70
3-40
Infrequent debris flows, low sediment transport
None; or low to moderate (<50% embedded)
1-6.5
8.0-16
Although the coastal tailed frog (Ascaphus truei) occurs throughout the Coast and
Mountains ecoprovince (see Demarchi 1993), its breeding habitats are vulnerable to
logging practices. A decline in tadpole abundance following timber harvesting has been
well documented and is primarily driven by sedimentation effects (Gaige 1920; Noble
and Putnam 1931; Metter 1964; Bury 1983; Corn and Bury 1989; Aubry and Hall 1991;
Bull and Carter 1996; Dupuis and Steventon 1999; Biek et al. 2002; Welsh and Lind
2002). This effect occurs at least in the short to mid-term (1 to 20 years), until sediment
additions have had a chance to flush through the system. Dupuis et al. (2000) suggest
that impacts are greatest in creeks with higher sedimentation risks (e.g., gullies, poor rock
types, or thick glacial sediments), most dramatic in creeks with high water power (steep
relief, high debris flow risk, high discharge rate), and longest in small creeks (first to
third order) with low water transport potential. Sediment fills the interstitial spaces
between large rocks, thereby reducing the availability of foraging substrates and refuge
sites. Tailed frogs rely on clean, coarse substrate and plunging turbulent flow. High
sediment loads can reduce habitat quality by in-filling the interstitial space between larger
clasts, and further by washing out step-pool bedforms and causing braiding. High
sediment loads during floods will also cause direct mortality by trauma.
Aquatic life stages can be further impacted by changes in a watersheds hydrological
regime. These effects are associated primarily with road construction, but also with tree
removal (Jones and Grant 1996). Roads intercept shallow groundwater and convert it to
surface flow in ditch lines. Surface flow is much more rapid than groundwater flow, thus
road networks can increase the drainage efficacy in the landscape and so alter the flow
response. In some cases causing an increase in storm peak discharges. The importance of
this effect on coastal creeks is now not thought to be significant, and is overshadowed by
sedimentation effects.
Any possible hydrologic effects must be reconsidered in the context of climate change. In
more interior sites the elevation distribution of clearcuts is important. In clearcuts, snow
melts faster. Thus, at higher elevation sites, reduced snowpack and earlier snow melt,
coupled with higher evapotranspiration in early summer, could lead to significantly
earlier spring peak flows and reduced baseflow volumes in the late summer period. From
the point of view of tailed frogs, this change in climate would lead to a significant
contraction of critical habitat in many places.
Declines in the number of terrestrial, post-metamorphic (juvenile and adult) Ascaphus
following timber harvesting have also been reported (Dupuis and Friele 2002; Aubry
2000; Maxcy 2000; Richardson and Neil 1998; Bull and Carter 1996; Corn and Bury
1991). Older forests are structurally complex and productive (Franklin 1988), providing
more tree, shrub and ground cover, diversity and stratification than closed canopy stands.
The large array of insect niches in complex understories provides tailed frogs with
unlimited foraging opportunities. The climate in old forests is also more stable and cool
(Chen et al. 1992), facilitating movement and dispersal of the adults and juveniles, which
do not tolerate high temperatures and rates of evapotranspiration (Claussen 1973).
Red-legged frog
Red-legged frogs (Rana aurora) breed in cool ponds, marshes, lake margins, swamps, or
slow-moving streams (Leonard et al. 1993; Corkran and Thoms 1996). These
waterbodies must have emergent vegetation for egg masses to be deposited on, and they
must hold enough water to support tadpoles until metamorphosis. Throughout the nonbreeding season (11 months of the year), adult red-legged frogs live along forest steams
and seepages. They can range far from open water when conditions are moist, and prefer
mature forests (> 80 years) with an abundance of coarse wood and leaf litter on the forest
floor (Orchard, pers. com.; Dupuis, pers. obs.). Breeding, foraging and overwintering
sites tend to overlap and be contiguous.
Rana aurora is of special concern in British Columbia (Cosewic 2002) primarily as a
result of exotics (introduced fish, bullfrogs and green frogs; these compete with and/or
prey on tadpoles/small frogs) and habitat degradation. Water bodies are often eliminated
for urban, commercial or industrial development, or they become contaminated from the
application of household or industrial chemicals; due to their semi-permeable skin,
amphibians are vulnerable to mutagenic effects from herbicides, pesticides and other
toxins (Bonin et al. 1997). Other threats to the aquatic life stages include parasitism
(e.g., the yeast parasite Candida numicola is transmitted through water and feces;
Cosewic 2002), water levels that are too low to support full development of tadpoles, and
elevated water temperatures. High temperatures could adversely affect egg development
since R. aurora has the lowest maximum temperature tolerance of North American ranids
(Licht 1971). Similarly, high UV-B levels can disintegrate the protective jelly layer
around the embryos, causing skin burns and eye cataracts to develop amongst the larvae
(Ovaska et al. 1997). Global warming is likely to enhance the climate-related stress
factors of this cold-adapted species.
Terrestrial-bound individuals are also susceptible to declines, associated with the loss of
riparian forest and with landscape fragmentation. Low soil moisture content, high
ambient temperature, and the drying power of the air, cause dehydration in amphibians
(Spotila 1972). When conditions are dry (July to August in particular) red-legged frogs
avoid desiccation by seeking cool, moist refugia such as seepages and stream banks.
Through the remainder of the year, this species relies on the protective forest canopy,
large downed logs and thick leaf litter layers. In the absence of such features, movement
and foraging rates can decline drastically, thereby affecting the overall fitness of
individuals (Feder 1983; Heatwole 1962). Thermal cover is especially critical along
dispersal avenues because a low disperser survival rate can render a population nonviable (Pulliam 1988). With the advent of global warming, the availability of moist, cool
cover will only increase in value and necessity.
3. STUDY AREA
Mount Elphinstone is located upslope of the unincorporated town of Roberts Creek (Fig.
1) between Gibson and Sechelt, within the Sunshine Coast Forest District. It lies within
the Dry Maritime Coastal Western Hemlock (CHWdm) biogeoclimatic subzone. Climate
is characterized by warm, relatively dry summers and moist, mild winters with little
snowfall.
Terrain consists of a thick blanket of glacial drift (i.e., till, glaciomarine, glaciofluvial
deposits) lying on a gentle slope rising from the sea. Materials are generally well drained
supporting podzolic soils. Creeks are generally incised in the drift, flowing in ravines up
to 10 m deep. Small sidewall failures and areas of bank erosion are relatively common
along creeks. The forest is comprised of mature (110-130 year-old), logging and fireorigin stands dominated by Douglas-fir (Pseudotsuga menziesii) and western hemlock
(Tsuga heterophylla), with some pockets of western redcedar (Thuja plicata) and red
alder (Alnus rubra). Overstory canopies range from closed to moderately open with
moss/lichen mats dominated by stepladder feather moss (Hylocomium splendens).
The Mount Elphinstone proposed protection area consists of the gentle terrain extending
above the main highway and lying between deeply incised Chapman and McNair Creeks.
This area contains six small to mid-sized watersheds, extending from sea level to 1130 m
in elevation above Georgia Straight (Fig. 1). Wilson Creek flows along the western edge
of the subject area, and contains the Hudson and East Wilson tributaries; there are two
small wetlands near/in its headwaters. Flume Creek is east of Wilson Creek. At 200 m
elevation, it is joined by outflow from a large, privately owned, permanent pond. The
neighbouring Roberts Creek drains the largest basin (14 km2) and includes two prominent
tributaries, Gough and Clack Creeks. Drainages at the east end of the area of interest
include Stevens Creek, which is ephemeral, and Robinson, locally known as Clough
Creek.
4. METHODOLOGY
Tailed frog assessment
Tailed surveys were conducted August 27-28, 2004 and data was compiled from previous
work (Dupuis and Waterhouse 2001). Every significant perennial tributary of the Mount
Elphinstone proposed protected areas boundary was sampled (Fig. 1). Time-constrained
searches (TCS) of 30 minutes were employed as outlined in the RIC Standards (BC
Ministry of Environment and BC Ministry of Forest 2001a). Parameters measured or
estimated at each survey site included location (UTM), reach gradient, water temperature,
a description of channel conditions including geologic processes (floods, sediment pulses,
avulsions, braiding), channel geometry (width, depth), substrate, and the diameter of the
ten largest clasts moved by flow (i.e. imbricate clasts). The number and cohort class of
all tailed frogs was recorded.
Tailed frogs populations are primarily governed by geomorphologic processes (Dupuis
and Friele 2003; Dupuis et al. 2000). Thus for each sample site, the contributing basin
was manually digitized and the areas calculated. Basin ruggedness (Melton’s number;
Melton 1965) was calculated as relief above the sample site (H) divided by the square
root of basin area (A1/2). It differs from a simple rise over run estimate of slope, by
accounting for basin shape (the square root of the area). Stream discharge was calculated
using the cross-sectional area (A; width x depth) multiplied by velocity (V), to give
discharge (Q). Flood velocity was derived using the approach of Costa (1983), whereby
the mean diameter (mm) of the ten largest clasts (D90) moved by the flow is entered into
the power function: V=0.18*(D90)0.487. Bankfull discharge is considered roughly
equivalent to the two-year return flow (Q2) (Knighton 1984; Whiting et al. 1999) and for
a given region is related to basin area and slope.
Red-legged frog assessment
The red-legged frog habitat assessment consisted of air photo interpretation. Location,
riparian status, size, and presence/absence of stream connectivity, were recorded for all
detectable (i.e., >10x10m) ponds in the Mount Elphinstone area. Given that financial
restrictions prevented any field verification of the map work, the results of a 1997 aquatic
survey of the Roberts Creek Demonstration Forest and nearby classified wetlands were
used (Dupuis and Waterhouse 2001).
4. RESULTS
Tailed frog distribution and abundance
Tailed frogs were present in all drainages on the slopes of Mt. Elphinstone (Table 2).
Creek
Table 2: Tailed frog distribution patterns on Mount Elphinstone
[based on Aug 2004 surveys and Dupuis and Waterhouse (2001)]
Survey site Basin Ruggedness Discharge Water
Tailed frogs
(elev in m)
size
(overall
Rate
Temp tadpoles (tads)
(km2) slope; %)
(m3/s)
(°C)
Wilson
Midslope
(320 m)
Midslope
(400 m)
Midslope
(320 m)
Upper slope
(400 m)
8.4
27
1.3
15
2 tads/30 min
1.3
11
0.8
29
1.3
14
2.1
33
0.4
14
2.8
37
1.1
14
1.7
31
2.1
12
7 tads/min
Gough
Midslope
(260 m)
Headwater
(730 m)
Midslope
0.6 tads/m2 in
1995/97
0 tads; present
in drainage
0 tads/30 min;
(0.3 tads/m2 in
1995/97
1 metamorph
4.6
42
2.5
15
Clack
Clack
Headwater
Upper slope
0.8
23
n/a
n/a
Clack
Midslope
(240 m)
Lower slope
(135 m)
Upper trib
(690 m)
Midslope
(~ 80 m)
Upper
Mainstem
(660 m)
Mainstem
(75 m)
West trib
(490 m)
3.1
40
3.0
15
11 tads/30 min;
0.8 tads/m2 in
1995/97
0 tads
3.7 tads/m2 in
1995/97
21 tadpoles
11.0
30
3.4
15
0
0.3
26
0.3
13
0 tads
--
--
n/a
n/a
0 tads
3.1
19
1.3
12
0;seen in past
13.9
25
3.2
15
0;seen in past
0.7
72
0.5
12
7 tads/min
East Wilson
East Wilson
Flume
Flume
Gough
Clack/Gough
Roberts
Stevens
Roberts
Roberts
Robinson
Basin sizes are small, ranging from 0.3 for a small upslope tributary of Roberts Creek, to
13.9 km2 for Roberts Creek near sea level (Table 2). Terrain is gentle in the subject area
with an average, overall basin slope of 36%. Reach gradients vary from 1-15%. Water
temperatures are warm (12 to 15°C in late August 2004; 13-14°C in mid July 1997
(Dupuis and Waterhouse 2001)).
Tadpoles were generally absent from the headwaters of creeks. Numbers were low to
moderate in the Wilson, Flume and Roberts Creek drainages, moderate in Gough Creek,
and high in the Clack Creek sub-basin.
Red-legged frog distribution and abundance
Based on an overview of air photos, most detectable wetlands are in the Wilson and
Flume Creek drainages (Table 3). There are number of small forested ponds with
riparian forest and connectivity to streams, but the status of red-legged frogs in these is
unknown.
Table 3. Wetlands in the Mount Elphinstone area
Location
Wilson/E. Wilson (below
confluence; developed area
Wilson Cr. headwaters
Wilson Cr. headwaters
Flume Cr. (Cromley property)
Steven Cr headwaters
(400 m North of)
Gough Cr. headwaters
North of Ouillet Cr.
Parkdale
E.Wilson/Flume
Private, landscaped; 550 m
from Flume Cr.
Private, forested; 75m from
Flume Cr.
Private and forested (O’Neill);
75m from Flume Cr.
Size
(m)
Type
Riparian zone
Connectivity to
a stream
10 x 85
Channel wetland
intact
Yes (forest)
225 x
75
100 x
45
Channel wetland;
no open water
Channel wetland;
7x10 m of open
water
Pond
Logged-north side
Yes (forest)
intact
Yes (forest)
Intact shrub fringe,
field, forest margin
intact
Yes (culvert)
225 x
75
30 x 15
(each)
Open water?
small
100 x
20
30 x 8
45 x 15
60 x 30
no open water
Pond complex
logged
One intact
One partly intact
One logged
15 x 15
30 x 15
Forest pond
Pond
intact
None
5 x 40
Forest pond
Intact
15 x 15
Forest pond
Intact
Forested pond
Contiguous forest
to Flume and
Wilson (app. 650
m)
no
Forest link
between 2 ponds,
240 m apart
250 m from cr.; 30
m to ephem. cr.
No connectivity
Forest within 4075 m
Forest (75 m to cr.)
Forest (75 m to cr.)
There is but one large pond with open water on the west slopes of Mount Elphinstone. It
is situated mid slope along Flume Creek, to the north of the mainstem (air photo 9008225). This pond is privately owned by Mr. Pat Cromley. When surveyed on March 23,
1997, it yielded a high density of red-legged frog egg masses (n = 63; Dupuis and
Waterhouse 2001). The only other significant wetland is a high elevation pond complex
towards the Mount Elphinstone summit, 400 m above Ouillet Creek. These four small
likely occur on crown land, are partially logged. They have never been investigated, but
are probably too high in elevation to support red-legged frogs.
In August 2004, two red-legged frogs were encountered along Gough Creek: an adult in
the headwaters and a juvenile midslope. Gough Creek is adjacent to Flume and East
Wilson Creeks, where the wetlands are concentrated. During two years of research in a
demonstration forest along East Wilson and Flume Creeks, Dupuis and Waterhouse
(2001) encountered 9 red-legged frogs on the banks of these two shaded streams, and
captured 25 (in pitfall arrays) in the forests intercepted by East Wilson and Flume Creeks.
5. CONSERVATION
Tailed frog protection priority
The creeks of Mount Elphinstone are incised in a thick blanket of surficial deposits,
primarily till. For this reason, there is a tendency for ephemeral flow in the headwaters,
and a relatively high rate of sediment movement derived from bank erosion. High
sediment production leads to higher proportion of fines (pebbles and sand), and greater
embeddedness of coarse substrates. This is especially true in basins with lower
ruggedness value, which lack the flushing potential of steeper creeks. Consequently,
tailed frog habitat quality tends to be relatively low, as reflected in the tadpole densities
of Wilson, East Wilson, and Flume Creeks. Tadpole numbers were moderately high in
Gough and Robinson Creeks, which had higher ruggedness values and are slightly larger
creeks (Table 2). Tadpole numbers are consistently high in Clack Creek (in 1995, 1997,
and 2004 surveys) because this creek has not only a moderate ruggedness (40%) and
optimal basin size at midslope (3.0 km2), but a predominance of boulders in the channel
bedload (e.g., 30% cover at the sample site) and low levels of fines (25% sand and
pebbles).
Tadpole abundances in Clack Creek are similar to abundances observed in McNair
Creek, to the north of Mount Elphinstone. In McNair Creek (September 7, 2004; personal
data), abundance ranged from 15-25 animals/30-minute search at sites within basin areas
from 0.5-5 km2. These tailed frog numbers are higher than along the Sea-to-Sky Corridor
from Horseshoe Bay to Whistler. On that transect, the highest abundance of tadpoles
ranged from 10 to 15 individuals per 30-minute search (average of 12 tadpoles/30
min.)(Ascaphus Consulting 2003).
Clack Creek represents a suitable Wildlife Habitat Area (WHA) for part of the Sunshine
Coast. In addition to having the right morphometric characteristics to sustain good
tadpole populations, Clack Creek is relatively undisturbed with few road crossings.
Forests are mature for most of its length (mature stands represent recruitment of future
old growth, and are especially valuable in the vicinity of cities, where developmental
pressures are high). Also, Clack Creek is comprised of two perennial tributaries (Clack
and Gough Creeks). Forked or dendritic watercourse provide more linear breeding
habitat, and promote the exchange of individuals between tributaries. Such metapopulation dynamics are critical for the long-term survival of sedentary species like tailed
frogs, because greater gene flow leads to greater population fitness. The headwaters of
Gough and Clack Creeks also provide dispersal corridors into the neighbouring drainages
of Dakota and Chapman Creeks, increasing the value of the WHA as a safeguarded
species pool in an increasingly popular urban centre.
Red-legged frog protection priority
Red-legged frogs have a very small range in B.C. They are in decline in the lower
mainland because of habitat loss, toxic contamination, and exotic species (particularly
bullfrogs). Since 1827, wetland area has decreased from 10 to 1% in the lower Fraser
Basin ecosystem, and coniferous forest declined from 71 to 54% (BC Ministry of Water,
land and Air Protection and BC Ministry of Forest 2004). There is but a single large,
low/mid elevation, open-water pond on the west slopes of Mount Elphinstone, privately
owned by citizen Pat Cromley. Currently, forests link this large wetland to nearby
streams and smaller, wooded ponds. A higher elevation open-water pond complex exists
near the summit of Mount Elphinstone. Given that the distribution limit of this species is
roughly 900 m in elevation (Corkran and Thoms 1996), R. aurora is likely to be less
reproductively successful at this elevation (shorter breeding season). There are relatively
extensive wetlands in the headwaters of the Wilson Creek drainage, but open-water was
not detected in these on the aerial photographs.
Mr. Cromley’s pond has no (or very low) flow and is structurally complex; two attributes
sought for by R. aurora. In particular, there is an abundance of thin-stemmed, emergent
plants along the margins of the littoral zone, which are ideal for red-legged frog egg
laying (Storm 1960). That Mr. Cromley’s pond is optimal red-legged frog habitat is
reflected in the high number of larvae (n = 9 tadpoles in one sweep) and egg masses (n =
83 in a visual survey the length of the pond) reported there during a 1997 survey. To my
knowledge, Mr. Cromley’s pond is free of exotic species such as trout, bullfrogs and
green frogs. It has a healthy riparian zone that consists of a thick fringe of native shrubs,
bordered by meadows, and upslope forests. The high encounter rate of juvenile and adult
frogs in the adjacent creeks (E. Wilson Cr. and Flume Cr.) and forests during the
summers of 1995 and 1997 (n = 34 encounters; Dupuis and Waterhouse 2001), suggests
that Mr. Cromley’s well cared for pond is a significant species pool for red-legged frogs
in the Mount Elphinstone area. A survey of R. aurora habitat suitability in the headwaters
of the Wilson Creek drainage is needed, to fully understand the role Mr. Cromley’s pond
plays in this species long-term survival in the area.
5. PROTECTION AND MANAGEMENT SUGGESTIONS
Under the Forest Practices Code, Wildlife Habitat Areas (WHA), as defined by the
Identified Wildlife Management Strategy (BC Ministry of Environment and BC Ministry
of Forests 2004), may be proposed for identified wildlife, such as tailed frogs and red-
legged frogs. In general, a WHA is defined, and within it features may be delineated
where special habitat protection is required.
Tailed Frog protection/management
For tailed frogs the existing WHA design is a roughly 20-ha reserve, consisting of 50-m
buffers along the perennial mainstem and tributaries of a designated creek. The 50-m
buffer includes a 30-m core area, and a 20-m management zone where restricted logging
operations are permitted. The WHA should include at least two streams with evidence of
tailed frogs. Priority should be given to creeks adjacent to mature or old forest, the
greatest potential to establish and maintain mature forest connectivity, optimal basin
morphometric characteristics, and high tadpole densities. Clack Creek, its tributary
Gough Creek, and the mature forest in between these two creeks meet all these criteria,
and can effectively protect the tadpoles and terrestrial life stages (juveniles and adults) of
an important tailed frog population on the Sunshine Coast.
The Clack WHA should extend from the perennial headwaters of Clack and Gough
Creeks to their confluence with Roberts Creek (Fig. 1). Roberts Creek is fish bearing and
already has riparian buffers. Although the reach below the Clack/Gough confluence does
not represent optimal breeding habitat, it is an important dispersal avenue for frogs
moving into neighbouring drainages. When riparian cover extends from a creek’s
headwaters to its confluence with a larger creek or river, the length of the channel is
protected from upstream disturbances that cascade downwards, and frogs are given
adequate protection against the adverse climate when foraging and when dispersing via
headwaters or mainstems.
The 20-m management zone of a WHA is geared to maintaining coarse substrates and
natural step-pool and cascade channel morphologies, restoring modulated peak flows,
protecting riparian vegetation, maintaining stable stream temperatures and protecting
adult foraging areas. Summer temperatures in these creeks are high (12-15°C), and could
become elevated to lethal (16-18°C) if flowing through long openings. Measures to
protect channel and riparian zones include prohibiting salvage operations and pesticide
applications, and using partial harvesting systems that aim to retain in the order of 70% of
the basal area in such a way as to minimize blow-down in the 30-m reserve zone.
Wherever possible, management zone should be augmented using wildlife tree retention
areas.
To protect channels, stream crossings must be minimized. When a stream must be
intersected, cross-drainage structures should be used, particularly bridges and openbottom culverts. Ditch runs in the vicinity of creeks should be short (<50 m) and should
not be directly connected to creeks, but should spoil water onto the forest floor allowing
sediment retention by rock armour or litter, and promoting groundwater recharge.
Measures to minimize impacts during the design and installation of cross-drainage
structures include (1) using sediment-control measures (armouring ditch lines and culvert
outfalls, grass-seeding, etc.) on cut-and-fill slopes; (2) deactivating roads with a minimal
of digging and disturbance to roadside vegetation; (3) falling and yarding away from
ephemeral and perennial channels; and (4) minimizing site disturbance during harvesting,
especially in terrain polygons with high sediment transfer potential to breeding reaches.
For details on road construction and maintenance refer to the Forest Road Engineering
Guidebook (BC Ministry of Forests and Ministry of Environment 1995a). Information
can also be obtained from the Soil Conservation Guidebook (BC Ministry of Forests and
Ministry of Environment 2001b), the Community Watershed Guidebook (BC Ministry of
Forests and Ministry of Environment 1996) and the Site Preparation Guidebook (BC
Ministry of Forests and Ministry of Environment 1995b).
Because watercourses have a continuous energy cascade, upstream activities have
downstream impacts. For example, if road construction or timber harvesting take place
along an unprotected tributary on the slopes to either side of a protected creek, sediment
from ditch-lines and gully sidewall failures could introduce excessive sediment into that
tributary, and this material would work its way downstream and negatively impact the
WHA. Sediment-control measures should thus not be limited to the 20-m management
zone, but apply to the entire catchment basin in which a WHA is situated, particularly
along channels that are directly linked to breeding or dispersal reaches. Additional basinwide considerations include (1) undulating road grades to disperse road surface water; (2)
maintaining naturally dispersed water flows by supplying cross-drainage structures at all
seepages, non-classsified drainages, and streams; (3) reducing the length of ditch runs,
and not spoiling ditchwater directly into defined channels; and (4) constructing narrow
roads to reduce site disturbance and groundwater interception in cut slopes. Logging
should be prohibited within gullies and slope stability class V polygons because of their
high potential for slope failures and sediment infusions into channels.
Red-legged frog protection/management
It is not possible to provide a conservation strategy for R. aurora in the Mount
Elphinstone area, until a thorough field investigation of its breeding and terrestrial
distribution patterns and local habitat associations has been conducted.
A red-legged frogs WHA design consists of a network of at least three small ephemeral
or perennial wetlands (each < 0.5 ha) within 300 m of each other. This design was
established because although terrestrial habitat is where a significant portion of redlegged frog feeding and growth occurs (up to 90% of the time), the spatial distribution of
red-legged frogs in the terrestrial environment is primarily related to the proximity of
suitable breeding habitat. Good aquatic habitat is comprised of wetlands with permanent
water, low flows, and high structural/microhabitat diversity. Mr. Cromley’s pond is
ideal, but the suitability of the Wilson Creek headwater wetlands for egg laying and
tadpole rearing is unknown. The location of all small forest ponds (undetected on air
photos) in the vicinity of Mr. Cromley’s pond is also unknown.
What constitutes good versus poor quality terrestrial habitat is unknown, but red-legged
frog numbers appear to decrease with increasing elevation and slope gradients (Bury et
al. 1991). Riparian habitats are more important than upslope coniferous habitats
(McComb et al. 1993) likely because these have a greater proportion of leaf litter (Gomez
and Anthony 1996) and downed wood (Aubry and Hall 1991). Maxcy (2000) found redlegged frogs to be more common in rotational forests than in clearcuts in British
Columbia, and radio-tracked red-legged frogs in clearcuts of Vancouver Island were
usually associated with streams (Chan-McCleod et al. 2000). Certainly red-legged frog
juveniles and adults have been encountered in abundance in the mature, low-elevation
forests between East Wilson and Flume Creeks (situated near Mr. Cromley’s large pond
and the Wilson Creek headwater wetlands).
Although an evaluation of potential red-legged frog WHA cannot be provided at this
time, it is clear that Mr. Cromley’s pond, the adjacent forests, and the riparian zones
along East Wilson and Flume Creek are of great importance to the local red-legged frog
population. With the accelerating rate of development in the area, the Sunshine Coast
Conservation Society might encourage Mr. Cromley to consider long-term protection of
his pond (e.g., a management covenant, stewardship agreement, or land easement). The
Nature Conservancy of Canada/BC Land for Nature can provide information regarding
habitat protection and tax breaks for private owners. Also, forest canopy, downed wood,
and the thick leaf litter in deciduous forest patches and riparian zones protect species that
are vulnerable to desiccation, and facilitate their movements across the landscape. A
strategically placed forest corridor linking Mr. Cromley’s pond with smaller ponds in the
area, and with the riparian zones of East Wilson and Flume Creeks, would protect
breeding, foraging and overwintering options for R. aurora in the face off future land
development. Conservation action could focus on encouraging wildlife tree patches
(WTP) and potential old-growth management area (POGMA) retention between the
ponds and the creeks (the mature forests along Flume and East Wilson Creek are ideal
candidates for old growth recruitment).
6. LITERATURE CITED
Ascaphus Consulting. 2004. Potential impacts to tailed frogs of the McNair Creek IPP
Letter to Dan Soprovich of Bluestem Wildlife Services, dated September 8th, 2004.
Swan River, MA.
Ascaphus Consulting. 2003. Protection ranking of tailed frog creeks in the Sea-to-sky
corridor, to guide the allocation of mitigation efforts during Highway 99 expansion.
Letter report to the Ministry of Transportation and Highways, dated September, 2003.
Vancouver, B.C.
Aubry, K.B. 2000. Amphibians in managed, second-growth Douglas-fir forests. Journal
of Wildlife Management, 64:1041-1052.
Aubry, K.B. and P.A. Hall. 1991. Terrestrial amphibian communities in the southern
Washington Cascade Range. United States Forest Service. General Technical Report.
PNW-GTR-285.
BC Ministry of Environment, Lands and Parks and BC Ministry of Forests. 2004.
Managing Identified Wildlife Guidebook and Species Accounts. Joint Publications,
Victoria, B.C.
BC Ministry of Environment, Lands and Parks and BC Ministry of Forests. 2001a.
Inventory Methods for Tailed Frog and Pacific Giant Salamander. Standards for
Components of British Columbia’s Biodiversity No. 39. Resource Inventory Branch,
MOELP, Victoria, B.C.
BC Ministry of Forests and BC Ministry of Environment. 2001b. Soil Conservation
Guidebook. Joint publication, Victoria, BC.
BC Ministry of Forests and BC Ministry of Environment. 1996. Community Watershed
Guidebook. Joint publication, Victoria, BC
BC Ministry of Forests and BC Ministry of Environment. 1995a. Forest Road
Engineering Guidebook. Joint publication, Victoria, BC.
BC Ministry of Forests and BC Ministry of Environment. 1995b. Site Preparation
Guidebook. Joint publication, Victoria, BC.
Biek, R., Mills, L.S., and R.B. Bury. 2002. Terrestrial and stream amphibians across
clearcut-forest interfaces in the Siskiyou Mountains, Oregon. Northwest Science
76(2).
Bonin, J., Ouellet, M, Rodrigue, J., DesGranges, J-L., Gagne, F., Sharbel, T.F. and L.A.
Lowcock. 1997. Measuring the health of frogs in agricultural habitats subjected to
pesticides. In Amphibians in Decline: Canadian Studies of a Global Problem (D.M.
Green, ed.). Herpetological Conservation 1: 246-257.
Bull, E.L. and B.E. Carter. 1996. Tailed frogs: distribution, ecology, and association with
timber harvest in northeastern Oregon. United States Department of Agriculture,
Forest Service, Pacific Northwest Research Station. PNW-RP-497.
Bury, R.B. 1983. Differences in amphibian populations in logged and old-growth
redwood forest. Northwest Science, 57:167-178.
Bury, R.B., Corn, P.S. and K.B. Aubry. 1991. Regional patterns of terrestrial amphibian
communities in Oregon and Washington. In Wildlife and Vegetation of Unmanaged
Douglas-fir Forests (L.F. Ruggiero, K.B. Aubry, A.B. Carey, and M.F. Huff, eds.)
USFS Portland, OR. Gen. Tech. Rep. PNW-285, pp. 341-350.
Chen, J., Franklin, J.F. and T.A. Spies. 1992. Contrasting microclimates among clearcut,
edge and interior of old growth, Douglas fir forest. Agriculture and Forest
Meteorology 1992: 1-19
Claussen, D.L. 1973. The water relations of the tailed frog, Ascaphus truei and the
Pacific treefrog, Hyla regilla. Comparative Biochemistry and Physiology. Great
Britain, Pergamon Press, 44A:155-171.
Corkran, C.C. and C.R. Thoms. 1996. Amphibians of Oregon, Washington, and British
Columbia. Lone Pine Publishing, Vancouver. 175 pp.
Corn, P. S., and R. B. Bury. 1991. Terrestrial amphibian communities in the Oregon coast
range. United States Forest Service. General Technical Report PNW-GTR-285.
Corn, P. S., and R. B. Bury. 1989. Logging in western Oregon: responses of headwater
habitats and stream amphibians. Forest Ecology and Management 29:39-57.
COSEWIC. 2002. COSEWIC Assessment and Status Report on the Red-legged Frog
Rana aurora in Canada. Committee on the Status of Endangered Wildlife In Canada.
Ottawa 22 pp.
Costa, J.E. 1983. Paleohydraulic reconstruction of flash flood peaks from boulder
deposits in the Colorado Front Range. Geol. Soc. of Am. Bull.: 986-1004.
Demarchi, D. 1993. Ecoregions of British Columbia, 3rd Ed. Map. British Columbia
Ministry of Environment, Lands and Parks, Victoria, B.C.
DeScaly, F., Slaymaker, O. and I. Owens. 2001. Morphometric controls and basin
response in the Cascade Mountains. Geografiska Annaler 83A (3): 117-130.
Dupuis, L. and P. Friele. 2004. Protection and Management Measures for the
Maintenance of Ascaphus montanus Populations in the Border Ranges, Based on
Habitat and Landscape Associations. Ministry of Water, Land and Air Protection,
Kootenay Region, Nelson, B.C.
Dupuis, L. and P. Friele. 2003. Watershed-level Protection and Management Measures
for the Maintenance of Ascaphus truei Populations in the Skeena Region. Ministry of
Water, Land and Air Protection, Skeena Region, Smithers, B.C.
Dupuis, L. and P. Friele. 2002. Distribution of Ascaphus montanus in the Yahk River and
neighbouring watersheds. Tembec Industries and Columbia Basin Fish and Wildlife
Compensation Program. Unpubl. Report. 31pp.
Dupuis, L., Friele, P. and F. Bunnell. 2000. Determinants of the tailed frog’s range in
British Columbia. Northwest Science 74: 109-115.
Dupuis, L. and D. Steventon. 1999. Riparian management and the tailed frog in northern
coastal forests. Forest Ecology and Management 124: 35-43.
Feder, M.E. 1983. Integrating the ecology and physiology of plethodontid salamanders.
Herpetologica 39: 291-310.
Franklin, J. F. 1988. Structural and functional diversity in temperate forests. In
Biodiversity. Edited by E.O. Wilson. Washington, D.C., National Academy Press.
pp. 166-175.
Frid, L., Friele, P. and L. Dupuis. 2003. Defining Effective Wildlife Habitat Areas for
Tailed frog (Ascaphus truei) Populations in Coastal British Columbia. Prepared by
ESSA Technologies Ltd., Vancouver, and Ascaphus Consulting, Squamish, for the
Ministry of Water, Land and Air Protection, Nanaimo, B.C.
Gaige, H.T. 1920. Observations upon the habits of Ascaphus truei Stejneger. Occ. Papers
of the Museum of Zool., University of Michigan 84: 1-11.
Gomez, D.M. and R.G. Anthony. 1996. Amphibian and reptile abundance in riparian and
upslope areas of five forest types in Western Oregon. Northwest Sci. 70: 109-119.
Heatwole, H. 1962. Environmental factors influencing local distribution and activity of
the salamander, Plethodon cinereus. Ecology 43: 460-472.
Jones, J.A. and G.E. Grant. 1996. Peak flow responses to clear-cutting and roads in small
and large basins, western Cascades Oregon. Water Resources Research, 32: 959-974.
Knighton, D. 1984. Fluvial Forms and Processes. Edward Arnold Publishers, Maryland.
Licht, L.E. 1971. Breeding habits and embryonic thermal requirements of the frogs, Rana
aurora aurora and Rana pretiosa pretiosa sympatric in southwestern British
Columbia. Can. J. of Zool. 52 (1): 116-124.
Maxcy, K.A. 2000. The response of terrestrial salamanders to forest harvesting in
southwestern British Columbia. University of British Columbia. Department of Forest
Science. M.Sc. Thesis. 91 p.
McComb, W.C., McGarigal, K. and R.G. Anthony. 1993. Small mammal and amphibian
abundance in streamside and upslope habitats of mature Douglas fir stands, Western
Oregon. Northwest Sci. 67: 7-15.
Melton, M.A. 1965. The geomorphic and paleoclimatic significance of alluvial deposits
in southern Arizona. J. of Geo. 73: 1-38.
Metter, D.E. 1968. The influence of floods on population structure of Ascaphus truei
Stejneger. Journal of Herpetology, 1:105-106.
Noble, G.K. and P.G. Putnam. 1931. Observations on the life history of Ascaphus truei
Stejneger. Copeia, 1931:97-101.
Ovaska, K. 1997. The vulnerability of amphibians in Canada to global warming and
increased solar ultraviolet radiation in Amphibians in Decline: Canadian Studies of a
Global Problem (D.M. Green, ed.) Herpetological Conservation 1: 206-225.
Pulliam, H.R. 1988. Sources, skinks, and population regulation. Am. Nat. 132: 652-661.
Richardson, J.S. and B.E. Neill. 1998. Headwater amphibians and forestry in British
Columbia: Pacific giant salamanders and tailed frogs. Northwest Science, 72 (Special
Issue No. 2):122-123.
Spotila, J.R. 1972. Role of temperature and water in the ecology of lungless salamanders.
Ecol. Monogr. 42: 95-125.
Storm, R.M. 1960. Notes on the breeding biology of the Northern Red-legged Frog (Rana
aurora aurora). Herpetol. 16: 251-249.
Welsh, H.H., Jr. and A.J. Lind. 2002. Stream amphibians of the Klamath-Siskiyou
region: relationships with forest and stream environments. Journal of Wildlife
Management 66(3): 581-602.
Whiting, P.J., Stamm, J.F., Moog, D.B., and R.L. Orndorff. 1999. Sediment-transporting
flows in headwater streams. Geol. Soc. Of Am. Bull. 111(3): 450-466.