China Creek Water Shrew Report - British Columbia

China Creek Hydroelectric Project Water Shrew Survey

Toth and Associates

Environmental Services

China Creek Hydroelectric Project Water Shrew Survey

Prepared for:

Upnit Power Limited Partnership

5500 Ahahswinis Drive

Box 211

Port Alberni, B.C. V9Y 7M7

Prepared by:

Steve Toth, AScT, R.P.Bio.

Toth and Associates Environmental Services 6821 Harwood Drive

Lantzville, B.C. V0R 2H0

November, 2005

Toth and Associates

Environmental Services

TABLE OF CONTENTS

1.0 INTRODUCTION ...................................................................................................4

2.0 BACKGROUND .....................................................................................................4

2.1 Study Area 5

2.2 Water Shrew Ecology 5

3.0 METHODS ..............................................................................................................7

4.0 RESULTS ..............................................................................................................10

4.1 Sample Site Descriptions 10

5.0 DISCUSSION........................................................................................................18

6.0 RECOMMENDATIONS.......................................................................................22

7.0 REFERENCES ......................................................................................................23

LIST OF TABLES

Table 1. Pitfall trapping results .........................................................................................10

LIST OF FIGURES

Figure 1. Study Area ...........................................................................................................7

Figure 2. Sample Site Locations .......................................................................................16

LIST OF APPENDICES

Appendix A: Field Forms .................................................................................................25

Toth and Associates 4

1.0 Introduction

Toth and Associates Environmental Services completed the Vancouver Island water shrew

(Sorex palustris brooksi) pitfall trapping surveys of the China Creek run-of-the-river

Hydroelectric Project south of Port Alberni, B.C. during August 2 – 6, 2005. A total of 40

pitfall traps were installed within the study area. One Vancouver Island water shrew was

captured approximately 200m downstream of the intake weir location on August 6, 2005. Two

vagrant shrews, three dusky shrews and one deer or Keen’s mouse were also captured. Trap

mortalities included one vagrant shrew, one dusky shrew and unfortunately, the water shrew.

2.0 Background

The initial environmental impact studies conducted on China Creek during October –

November 2003 and March 2004 by Cordillera Environmental Services did not include

sampling for water shrews. However, Cordillera did recognize the potential for Vancouver

Island water shrews on China Creek (Cordillera Environmental Services, 2004). The Ministry

of Water, Land and Air Protection (MWLAP) and the Canadian Wildlife Service (CWS) also

identified the potential for water shrews. Water shrews were not observed during any of the

wildlife surveys conducted on the China Creek by Cordillera, during any of the fisheries studies

conducted by Ecofish Research Ltd. and CBR and Associates, or during riverine bird surveys

conducted in May and July 2005 by Toth and Associates.

As the wildlife surveys conducted by Cordillera did not include riparian pitfall trapping, it was

recommended by Public Works and Government Services Canada (PWGSC) in their Canadian

Environmental Assessment Act (CEAA) Screening Report of the China Creek Hydropower

Project that directed pitfall trapping surveys should be conducted for water shrews

(Environmental Assessment Screening Report, October 2004). The PWGSC indicated in the

CEAA report that appropriate agency(s) (MWLAP) must be contacted prior to the initiation of

the surveys so the surveyor may receive the most recent Best Management Practices

Guidelines. All field investigations would follow the most recent sampling guidelines

(Recovery Team/Resource Information Standards Committee) to evaluate the extent and

suitability of Vancouver Island Water Shrew habitat and their presence.

In June 2005 Toth and Associates Environmental Services provided an outline for water shrew

surveys for the China Creek Run-of-the-river Hydroelectric Project. The survey was designed

China Creek Water Shrew Survey Report


at the Presence / Not Detected level. Toth and Associates has conducted over 43 environmental

assessments of land developments, including 9 environmental impact assessments of run-of-

the-river hydroelectric projects on Vancouver Island, 6 of which have included a riparian pitfall

trapping component.

2.1 Study Area

The China Creek Hydropower Project is located approximately 11 km southeast of Port

Alberni, B.C. The proposed Study Area for the water shrew pitfall trapping surveys was from

the proposed powerhouse / tailrace location to the intake weir location, providing an overall

study area length of approximately 4.9 km (Figure 1). In addition, an effort would be made to

include at least one sampling area upstream of the intake location, that according to the

available literature, had habitat with a higher capability / probability of supporting a water

shrew population.

2.2 Water Shrew Ecology

The Provincially red-listed Vancouver Island sub-species of common water shrew (Sorex

palustris brooksi) is restricted to Vancouver Island. The water shrew is a riparian dependent

species reliant upon intact functional riparian areas and is strongly associated with the land /

water interface. Most of the approximately 20 recorded occurrences are from swampy low

gradient productive watercourses such as Robertson Creek, tributaries to Lowry Lake, Black

Creek and tributaries to French Creek near Coombs. The common water shrew feeds primarily

on aquatic invertebrates but will also take terrestrial invertebrates, small fish and amphibians.

The Vancouver Island water shrew is not included on Schedule 1 of the Federal Species at Risk

Act.

The Vancouver Island Water Shrew is a subspecies of the common water shrew, identified as

occurring only on Vancouver Island, British Columbia. It is a Provincially red-listed species,

indicating that it is a candidate for endangered status. Only 9 specimens had been collected

from 7 localities on Vancouver Island during the period of 1897 to 1984 (Hartman, 2002).

Water shrew inventories completed by Lisa Hartman in 1997 (Results of 1997 Inventory of

Vancouver Island Water Shrew, 2002) yielded an additional 14 water shrew captures. Most of

the available literature concerning water shrews is based on the mainland subspecies; little in

the way of detailed habitat information was available for the Vancouver Island subspecies prior

to the work conducted by L. Hartman.



Two subspecies of common water shrew are recognized within British Columbia: S. p. brooksi,

on Vancouver Island, and S. p. navigator, occurring throughout the mainland of the province. A

second species of water shrew (Sorex bendirii) occupying the lowland areas of the Lower

Mainland and Fraser Valley is also red-listed (Nagorsen 1996). Only two other shrew species

occur on Vancouver Island; the vagrant shrew (S. vagrans) and the dusky shrew (S.

monticolus), both are terrestrial species.

The Vancouver Island water shrew is identifiable by its large size (in comparison to vagrant

and dusky shrews), charcoal grey dorsal fur, silver-grey ventral fur and bicoloured tail with

dark above and white-silver below. A key identifying characteristic is that the hind feet are

large and have a thick fringe of short, stiff hairs around the outer margin. They also emit a

fairly strong, musky odour that is somewhat similar to that of a skunk.

The water shrew can be active at all hours, but has two peak times of activity; within one hour

of dawn and one hour after dusk. The water shrew dives readily into water and can remain

submerged for periods of up to 30 seconds. The stiff hairs on the water shrew’s feet allow this

species to actually run on the water’s surface for short distances. The water shrew’s senses are

not well understood, but their sense of smell is well developed and it is thought that they may

use high frequency sounds for echolocation, as captive shrews continuously emitted a series of

rapid squeaks (Nagorsen1996). We have also heard this same “clicking squeak” emitted from

terrestrial shrews while foraging.

The water shrew feeds primarily on aquatic insects such as caddisflies, craneflies, stoneflies,

and mayflies, but will feed opportunistically on terrestrial prey including, slugs, spiders,

beetles, snails, crickets and have also been documented eating salmonid fry in fish hatcheries.

Water shrews hoard food in caches for later consumption.

The breeding season extends from December to September with pregnant females documented

from May to September. Two – three litters can be produced in a breeding season with 3 – 10

young in a litter. The maximum lifespan is approximately 18 months. Predators of Vancouver

Island water shrews likely include mink, herons, owls and snakes.

Shrews in general are difficult to study in the field because their small body size and high

metabolism render them vulnerable to trap mortality.



Figure 1. Study Area

3.0 Methods

The surveys were conducted according to Resources Inventory Standards Committee’s (RISC)

Standards for Components of British Columbia’s Biodiversity No. 31: Inventory Methods for

Small Mammals: Shrews, Voles, Mice and Rats (Version 2.0, May 1998) with methodologies

modified to include a longer trap check frequency and different pitfall trap lay-out. It was

determined early within the water shrew survey logistics and design phase that the RISC

recommended trap check frequency (every 1.5 – 2.0 hours) and pitfall transect lay-out would be

extremely difficult to achieve due to the limited access, rough topography and large size of the

study area. Trudy Chatwin (Rare and Endangered Species Biologist) at the Ministry of

Environment (MOE) in Nanaimo was contacted regarding modifying the water shrew inventory

methodologies. Trudy Chatwin asked us to contact Vanessa Craig, Ph.D., R.P. Bio. (Ecologic

Research) for detailed methods and practical advice. Vanessa Craig provided us with good

practical information regarding trap check frequency as it related to shrew pitfall trapping

mortality rates and a draft copy of the Vancouver Island water shrew inventory conducted by

Lisa Hartman in 1997 (Hartman 2002). Ross Vennesland (Species at Risk Recovery Biologist)

at MWLAP in Surrey was also contacted regarding the China Creek water shrew survey. Mr.

Vennesland is the Chairperson of the Provincial Pacific Water Shrew Recovery Team. Mr.



Vennesland provided us with a draft copy of the Best Management Practices Guidelines for

Pacific Water Shrew in Urban and Rural Areas (Craig and Vennesland, April 2005). The trap

check frequency recommended by V. Craig and L. Hartman was every 3 – 4 hours, and by R.

Vennesland was every 6 – 8 hours. The information provided by the persons contacted, and

within the reports and BMPs indicated that shrew trap mortalities are high regardless of trap

check frequency and that during L. Hartman’s 1997 inventory only one water shrew survived

capture.

A B.C. Ministry of Environment Wildlife Permit (Permit # NA05 – 14343) was issued to Toth

and Associates for this project.

Riparian area / river shoreline pitfall trapping surveys are the preferred method for surveying

common water shrews. Pit-fall index trapping lines were stratified according to accessibility

and to provide appropriate coverage of the diversion reach of the China Creek hydroelectric

project. Sample sites were biased towards covering those locations identified during the

background information review as having the most suitable water shrew habitat within the

diversion reach, and therefore the highest probability of success. Sample sites included the two

areas previously identified by Cordillera Environmental Services (2004) as having potential

water shrew habitat; namely the intake weir and the small tributary located approximately 200

m downstream from the weir location.

The RISC recommended protocol for water shrew surveys is to set an index line (transect) of

20 pitfalls at 15-m intervals, for a minimum of 300 m along the edge of the waterway being

sampled. However, as the goal was to determine presence and to appropriately cover the

diversion reach, we proposed pitfall sets at variable intervals over a transect length to be

determined by the habitat suitability at each sampling site. The diversion reach consists of

steep bedrock influenced channel morphology with only small areas of potential water shrew

habitat between bedrock chutes and cascades. Adherence to the 300 m transect length and 15

m interval would mean that much of the trapping effort on any transect would be expended in

areas with little potential of success, and would not be possible as pitfall trapping requires loose

substrates.

Pitfall traps were located within 5 - 15 cm of the wetted edge of China Creek and within 5 cm

of the water surface elevation. As water shrew pitfall trapping success is reliant on stable

stream flows, all reasonable attempts were made to conduct surveys during appropriate low

flow and fair weather conditions.

The RISC guidelines recommend that index traplines (transects) should be active up to a

maximum of 6 days to allow resident individuals sufficient time to encounter the trap line.



Longer periods may be required for rare species with long latency of detection periods;

however these latency of detection parameters had not yet been determined for water shrews.

Field gear included chest waders, cruiser vests, safety equipment, RISC field forms and field

notebooks, detailed maps of the study area, handheld GPS, headlamps, and waterproof 35 mm

camera. Trapping gear included:

• Pitfall traps

• Vapour barrier plastic (medium weight) for fencing

• Fencing tie wire

• Bait for traps

• Bedding and Floats for traps

• Cotton gloves

• Flagging tape

• Plastic sample bags

• A small vial of 10% sugar in water

• RBCM Handbook: Opossums, Shrews and Moles of British Columbia (Nagorsen1996)

• Pack board

Two sizes of Pitfall containers were used: 34 plastic buckets measuring 23.5 cm wide x 24 cm

deep, and 6 buckets measuring 20 cm wide x 24 cm deep. Drift fences were constructed out of

2 – 4 m long sections of 35 cm high vapour barrier plastic, staked in place with fencing wire.

Pitfall traps were also placed against naturally occurring structures such as logs and large

boulders. Pitfalls were dried, weighted down with cobble sized rocks to prevent floating,

supplied with bedding material (dry moss), bait (tuna cat food), and a cover (pieces of tree bark

or skunk cabbage leaves) raised approximately 5 – 8 cm above the lip of the bucket.

As the objective of the study was to determine the presence of water shrews within the study

area, pitfall traps were active 24 hours a day to maximize trapping effort. Traps were checked

every 6 - 8 hours during daylight hours. It was anticipated that to achieve this trap check

frequency, a more or less continuous circuit of the trap sets would be required during daylight

hours. The locations of the sample sites are indicated on figure 2.

Basic stream and riparian habitat conditions were recorded at each sampling unit on standard

stream survey Site Cards. The sites and trap sets were photographed and geo-referenced with a

handheld GPS.

All animals captured at each trap station were identified to species and photographed. The

water shrew trap mortality was placed in an individual labelled plastic bag and frozen as soon

as possible.



Observations of other fish, wildlife, and listed vegetation encountered during these surveys

were also recorded in field notes. The field surveys were conducted by Steve Toth and

Cameron Tatoosh.

4.0 Results

The results of the field surveys are provided in Table 1, below and in Field Forms (Appendix

A). The surveys performed covered approximately 756 m of the 4.9 km diversion reach, as

well as approximately 375 m of stream channel upstream of the diversion reach.

Approximately 3,152 hours of trap effort was applied.

Table 1. Pitfall trapping results

Trap

Site

# of

traps

Site

Length

(m)

Duration

(hours)

Total Effort

(hours)

Catch

1 6 172 103 618 0

2 5 198 96 480 2 vagrant shrews

3 5 136 76 380 0

4 8 133 68 544 1 dusky shrew, 1 mouse

5 6 117 70 420 1 water shrew

6 10 375 71 710 2 dusky shrews

The China Creek CEAA Screening Report produced by the PWGSC (2004) states in Appendix

D that “if SAR (Species at Risk) are identified to be present within the project area or identified

as being impacted due to project activities either prior to or during the construction activities, or

throughout the operation of the project, the appropriate agencies must be notified prior to the

commencement of any further activities”. Trudy Chatwin, Ministry of Environment Rare and

Endangered Species Biologist in Nanaimo was contacted on August 17, 2005 and informed of

the capture of a water shrew on China Creek.

4.1 Sample Site Descriptions

Site 1 was located upstream from the lower bridge crossing, located approximately 30 m

upstream of the powerhouse location (Photograph 1). Six pitfall traps were installed over

approximately 172 m on the south side of the creek. The site was primarily comprised of an

expansive gravel bar with some bedrock morphology near the upstream end of the site. Forest



cover on both sides of the stream at site 1 was comprised of a leave strip of young forest aged

second growth western hemlock, Douglas fir and red alder. The leave strip width varied

between 10 – 30 m. Stream banks were stable, but with little large woody debris or

complexity. Five of the pitfall traps were placed along the wetted edge of China Creek, while

one trap was placed at the wetted edge of an isolated off channel pool next to the south bank.

There were no captures at Site 1.

Photograph 1. View downstream through Site 1.

Site 2 was located approximately 1.5 km upstream of the powerhouse location. The site

consisted of 5 pitfall traps placed over approximately 198 m on the north side of the stream

(Photograph 2). Stable streambanks were located in close proximity to the water’s edge for

most of the site. Substrates consisted of cobble and small – medium sized boulders for most of

the site. Forest cover on both sides of the stream was comprised of mature forest cover,

dominated by western hemlock, western redcedar and Douglas fir with bigleaf maple and red

alder. Large woody debris was rare at this site. Two vagrant shrews were captured at Site 2

(Photograph 3).



Photograph 2. View upstream through Site 2.

Photograph 3. Vagrant shrew in pitfall trap at Site 2.

Site 3 was located approximately 150 m downstream of the City of Port Alberni intake dam

(Photograph 4). Five pitfall traps were installed over 156 m of stream with 4 traps on the south

side of the stream and 1 trap on the north side. Stream substrates were dominated by boulder



blocks and sorted gravels. The south bank was composed of fines and bedrock blocks while

the north side consisted of large diameter rip-rap. Forest cover consisted of mature coniferous

western hemlock dominated forest cover on the south side of the stream and a thin strip (5 – 10

m) of young red alder dominated tree cover below the intake dam access road on the south side

of China Creek. The resident at the house located at the city intake dam mentioned that the

water shrew we captured was the same animal that his dog was observed to capture (and eat)

below the intake dam on occasion. High numbers of large sized crickets were captured in

pitfalls at Site 3. Small mammals were not captured at this location.


Site 4 was located on a groundwater fed fish bearing tributary watercourse located on the north

side of China Creek approximately 200 m downstream of the intake weir location (Photograph

5). This site appeared to represent the best potential habitat for water shrews, with stable

stream flows and stream banks and abundant functional large woody debris. Eight pitfall traps

were placed along 133 m on the south side of the tributary. The steep, woody debris lined

banks and lack of bedload aggradation made this a difficult site for placement of pitfall traps.

Forest cover consisted of young western hemlock dominated tree cover with lush herb and

shrub layer development in the vicinity of the tributary. Although this site likely represented

the habitat with the highest capability of supporting water shrews, it was noted that aquatic

insects on stream substrates were rare in this tributary. One dusky shrew and one mouse (cover

photo) were captured at Site 4.




Site 5 was located immediately upstream of the confluence with the Site 4 tributary on China

Creek (Photograph 6). Six pitfall traps were installed over 117 m with five traps on the north

side and 1 trap on the south side of China Creek. Substrates consisted of boulders, bedrock

blocks and small amounts of sorted gravels. Forest cover consisted of young western hemlock

dominated coniferous tree cover. Stream banks were stable and had significant amounts of



stable large woody debris and tree roots. The pitfall trap placed at the upstream end (UTMs

10.376469.5447608) of Site 5 captured one water shrew (Photograph 7).


Photograph 7. View of Vancouver Island water shrew captured at Site 5.



Figure 2. Sample Site Locations



Site 6 consisted of 10 pitfall traps installed over 375 m of stream upstream and downstream of

the upper bridge crossing on China Creek (Photograph 8). This site had good potential for

water shrews due to the lower gradient and more meanderous channel morphology. Forest

cover consisted largely of mature red alder, bigleaf maple, western redcedar and western

hemlock with a well developed shrub and herb layer. Streambanks and bedload were stable,

with the wetted edge of the river in close proximity to the stream banks in most locations. Two

dusky shrews were captured at Site 6. Both captures occurred at one pitfall site, but did not

appear to be the same shrew (Photograph 9).



Toth and Associates Environmental Services 18

Photograph 9. View of dusky shrew captured at Site 6.

5.0 Discussion

One water shrew was captured during 3,152 hours of trapping effort. The fact that a water

shrew was captured on China Creek likely indicates that low numbers of water shrews are

present throughout the watershed in suitable habitats. The population may be limited by habitat

suitability and availability of prey.

Water diversion and operation of the facility may result in alienation of the Vancouver Island

Water Shrew from China Creek and fragmentation and/or disruption of their habitat (PWGSC

2004). However, activities associated with the City water intake, logging and mining may

cumulatively have had similar effects.

With the proposed release flows, there will be a reduction in wetted perimeter, water depth,

water velocity and frequency of flushing flows, thus reducing the area for fish habitat and

possibly affecting the aquatic ecosystem (PWGSC 2004). Although the project will reduce

flows and instream aquatic habitat in the diversion reach, DFO has required that a minimum

conservation flow of 15% MAD (0.51 cms at the intake) be maintained and that post-

construction flow monitoring must be undertaken directly downstream of the intake to ensure



that the minimum conservation flow is maintained at all times. DFO has also required the

development and submission of a ramping strategy to protect fish and aquatic habitat during the

shut down and start up of operations and a detailed monitoring plan for construction and post-

construction of the project. A detailed Environmental Management Plan, which provided

specific information on construction mitigation measures to be implemented during all phases

of this project was prepared and submitted to DFO prior to commencement of project

construction.

The operation of the China Creek Hydroelectric Project has the potential to impact metal

concentrations in China Creek (Public Works and Government Services 2004). Naturally

occurring zinc levels in China Creek already exceed the limits required for the protection of

aquatic life. These elevated metals may be a limiting factor to aquatic production and therefore

could also have an influence on water shrew populations. Monitoring recommendations

provided in the ECOfish report (2004), included monitoring for zinc, nickel, silver, total

phosphate and titanium. Environment Canada has recommended that if analysis or monitoring

indicates a change in levels of zinc or nickel that are above recommended concentrations for

aquatic life, mitigation measures are to be developed and implemented.

Based on the limited habitat information provided by the single capture of a water shrew during

this study, it would appear that suitable habitats might include those areas where the wetted

edge of China Creek is in close proximity to a stable stream bank. Functional, stable large

woody debris, overhanging vegetation and tree roots may also be an important factor.

However, Hartman (2002) did not find any clear association between water shrew occurrences

and the habitat variables measured. Water shrews were found in young and old forest sites

from 10m to 320m in elevation and were found in streams characterized by a range of widths,

depths, flows and bed materials. More quantitative data is needed to identify site-specific water

shrew habitat characteristics / requirements that would not be achievable using the current

RISC recommended sampling protocols.

All of the water shrew trapping reference material reviewed suggested that placement of pitfall

traps in close proximity to the water’s edge was crucial to water shrew capture success.

However, we would contend that the water shrew must navigate from its burrow site to the

water to forage and therefore should be subject to interception by pitfalls or other trap types

placed in this area. While the current pitfall trapping method does provide information

regarding shrew presence and foraging habitat, it does not provide precise information on water

shrew shelter / burrow habitat, as it is not possible to tell with any certainty where the captured

water shrew came from. A possible alternate trapping method could involve extending a



measured section of drift fence from the stream bank in a shallow V shape, with placement of a

pitfall in the notch of the V fence. This set-up could be moved every 24 – 48 hours to sample

the next section of stream bank. This method would be entirely quantitative, allowing

estimation of area sampled, habitat used / not used, likely reduce mortality rates and would be

less subject to flooding / floating, as it would not be necessary to place pitfalls in close

proximity to the water’s edge. Most importantly it would allow accurate evaluation of what

constitutes good water shrew shelter / burrow habitat. This information potentially could be

applied to similar habitats elsewhere, and could eventually provide estimates of habitat

capability / relative abundance. Captured shrews could be marked with hair dye and the stream

bank within the capture site could be monitored for water shrew activity (essentially recaptures)

using remote cameras. The effective range on most of the commercially available remote

cameras is approximately 10 - 20 m, but due to the small size and heat signature of a shrew it

would be necessary to use one camera approximately every 5 m. Remote camera sites could be

baited to draw small mammals within close range of the camera. The use of remote cameras

would also provide valuable information on water shrew activity (i.e. peak periods, duration,

frequency).

Water shrews are noted for their strong musky odour, produced by numerous scent glands on

the body; most predominantly the flank glands on male shrews. A potential method for water

shrew detection of which we have not found any mention in the literature, but may be highly

effective, would be to use dogs that have been trained to detect the “skunky” odour of water

shrews.

Although the recorded number of captures and locations of water shrews on Vancouver Island

are low, it is not unheard of for this species to be captured in minnow traps during fisheries

surveys or observed by others who work in the bush, but is generally not reported or is

mistaken for another species. We are aware of several instances of multiple water shrews being

captured in minnow traps and have made attempts to provide this information to the B.C. CDC.

Possible areas that are not utilised by water shrews may include those areas on China Creek

with wide gravel / cobble bars, unstable banks with little habitat complexity and areas of

bedload aggradation. However, until further site specific data is collected regarding water

shrew habitat utilisation and life requisite requirements, all the riparian and stream channel

habitat on China Creek should be considered as potential critical habitat for the China Creek

water shrew population. Unfortunately, blasting and construction of the intake weir site had

already commenced prior to this study; it is not possible to tell if construction activities resulted

in any water shrew mortalities.



The construction of the penstock has primarily occurred outside of the riparian area and the

likely zone of water shrew utilization. Two footprint impacts have been realised at the

powerhouse and intake weir location, resulting in the alienation of approximately 2,600 m2 of

streamside habitats.

Considerable loss of primarily terrestrial vegetation and wildlife habitat has resulted from the

construction of the intake, penstock, and access roads. Some vegetation clearing did occur

during the breeding bird season. It is not known if a breeding bird survey was undertaken of the

penstock route prior to construction.

During this study adult red-legged frogs were observed frequently along China Creek.

Previous information indicated that it was unlikely the hydro project would have an impact on

the blue-listed red-legged frog population. However, from what was observed during this

study, reduced flows as a result of hydro project operations may have an impact on red-legged

frogs within the diversion reach through reduction of aquatic habitat. It is important that

restoration of the penstock and access road areas include reinstatement of coarse woody debris

in these areas.

It is difficult to assess the potential impacts on China Creek’s water shrew population posed by

the operation of the China Creek Hydroelectric Project. China Creek is typical of previously

logged Vancouver Island streams, with high peak flows and quick response times. The valley

is narrow and steep sided with little in the way of side channel or off channel fish habitats.

Reduced average flows may have an initial impact by increasing the distance between the

stream bank and the wetted edge of the creek. However, it is unlikely that this area will be

significantly reduced from current conditions during the peak period of water shrew activity of

approximately May – September, due to the requirements for maintaining instream flows for

resident fish populations during that same period. Likewise, the project will not have a

significant effect on reducing peak flood flows.

Flow control through the diversion reach resulting from hydro operations may actually result in

a net increase in riparian habitats as the land / water interface is colonized by plants, effectively

reducing the distance between the riparian edge and the edge of the water in some locations

(i.e. large gravel bars). Reduced flows may also result in a net increase in aquatic insect

populations by creating a more stable environment, reducing bedload movement, allowing

increased periphyton growth, and allowing nutrients to remain in the system for longer periods.



6.0 Recommendations

It is imperative that the China Creek project includes continued post-construction monitoring of

the China Creek water shrew population. Given the very short life-span of this species of 12 –

18 months, two or three years of poor recruitment / survivorship as a result of hydroelectric

operations could result in loss of this red-listed species from the diversion reach of China

Creek. Therefore, it is important to determine whether or not the hydroelectric project’s

operation is having a negative impact on the China Creek water shrew population.

We recommend that there be continued inventory of water shrews on China Creek in 2006 with

follow-up monitoring in 2007 and potentially 2008, depending upon initial results from 2006,

2007. The objectives of the inventory should be to ascertain extent of occurrence (using RISC

standards), habitat utilisation (capability / suitability) and relative abundance (using methods

discussed in Section 5.0), possible limiting factors and habitat mitigation / compensation

strategies. The inventory should include detailed surveys of aquatic and terrestrial insect

production. The objectives of follow-up surveys should be to monitor / evaluate the effects of

the China Creek Hydropower Project’s operations on the water shrew population. All water

shrew surveys undertaken will require increased trap check frequencies / field effort to ensure

that surveys result in minimal water shrew trap mortalities.

Sincerely,

Steve Toth, AScT, R.P.Bio.

Toth and Associates Environmental Services



7.0 References

B.C. Ministry of Environment, Lands and Parks, B.C. Ministry of Forests. 1998. Field Manual

for Describing Terrestrial Ecosystems, Land Management Handbook No. 25. 214 pp.

B.C. Ministry of Environment, Lands and Parks, Resources Inventory Branch. 1998. Species

Inventory Fundamentals. Standards for Components of British Columbia’s Biodiversity

No. 1, Version 2.0. 119 pp.

B.C. Ministry of Environment, Lands and Parks, Resources Inventory Branch. 1998. Inventory

Methods for Small Mammals: Shrews,Voles, Mice & Rats. Standards for Components

of British Columbia’s Biodiversity, No. 31, Version 2.0. 131 pp.

Cordillera Environmental Services 2004. China Creek Power Project Wildlife Impact

Assessment and Penstock Stream Crossing Inventory.

Craig, V. and R. Vennesland. April 2005. Best Management Practices Guidelines for Pacific

Water Shrew in Urban and Rural Areas, Working Draft. 38 pp.

Demarchi, D. 1996. An introduction to the ecoregions of British Columbia. MELP, Wildlife

Branch. Victoria, B.C. 46 pp + appendices.

ECOfish, March 2004. China Creek Hydroelectric Project – Assessment of Fish Habitat

Impacts and Mitigation / Compensation.

Green, R.N. and K. Klinka. 1994. A field guide for site identification and interpretation for the

Vancouver Forest Region. Land Management Handbook Number 28. BC Ministry of

Forests. Victoria, B.C. 285 pp.

Hartman, L. 2002. Results of 1997 Inventory of Vancouver Island Water Shrew.

Luttmerding, H.A., D.A. Demarchi, E.C. Lea, D.V. Meidinger and T. Vold. 1990. Describing

Ecosystems in the Field, Second Edition. BC Ministry of Environment, Lands and

Parks, BC Ministry of Forests. Victoria, B.C. 213 pp.

Meidinger, D. and J. Pojar. 1991. Ecosystems of British Columbia. BC Ministry of Forests.

Victoria, B.C. 330 pp.

Nagorsen, D. 1996. Opossums, Shrews and Moles of British Columbia. Volume 2: The

Mammals of British Columbia. Royal British Columbia Museum Handbook. Victoria,

B.C. 169 pp.



Nagorsen, D. 1990. The Mammals of British Columbia: A Taxonomic Catalogue. Royal British

Columbia Museum, Memoir No. 4. Victoria, B.C. 140 pp.

Nuzdorfer, F.C., N.L. Nuzdorfer, A.M. Scagel, K. Klinka, T. Lewis, P. Courtin and R.N.

Green. 1994. Biogeoclimatic Units of the Vancouver Forest Region, Map Sheet 5 of 6.

Southern Vancouver Island and Sunshine Coast. B.C. Ministry of Forests. Prepared by:

Hugh Hamilton Ltd. Vancouver, B.C.

Public Works and Government Services Canada, Environmental Services – Pacific Region,

October 2004. Environmental Assessment Screening Report of the China Creek Hydro

Power Project.



Appendix A: Field Forms

Project Name China Creek Hydroelectric Project Water Shrew Survey Surveyors: Steve Toth, Cameron Tatoosh

Dates: August 2 – 6, 2005

# of Transects 6 Transect Lengths 1 = 172 m, 2 = 198 m, 3 = 136 m, 4 = 133 m, 5 = 117 m, 6 =

375 m

UTMs of d/s end 1 = 10.373272.5449500

2 = 10.373660.5449138

3 = 10.374338.5448658

4 = 10.376460.5447643

5 = 10.376511.5447620

6 = 10.378865.5446869

UTMs of u/s end 1 = 10.373341.5449416

2 = 10.373695.5448954

3 = 10.374387.5448585

4 = 10.376479.5447581

5 = 10.376602.5447595

6 = 10.379118.5446974

Transect Effort 1 = 618 hrs, 2 = 480 hrs, 3 = 380 hrs, 4 = 544 hrs, 5 = 420 hrs, 6 = 710 hrs

Weather: Clear, warm and sunny, no precipitation, winds calm.

Survey Type Riparian Pitfall Trapping Site # Trap # Date Set

Time

Date Check

Time

Captures

Comment

Date Check

Time

Captures

Comment

Date Check

Time

Captures

Comment

1 1 Aug. 2 09:00 Aug. 4 08:40 0 Aug. 5 15:20 0 Aug. 6 15:25 0

1 2 Aug. 2 10:00 Aug. 4 08:42 0, floated Aug. 5 15:25 0 Aug. 6 15:30 0

1 3 Aug. 2 10:10 Aug. 4 08:53 0 Aug. 5 15:35 0 Aug. 6 15:35 0

1 4 Aug. 2 10:25 Aug. 4 09:00 0 Aug. 5 15:45 0 Aug. 6 15:45 0

1 5 Aug. 2 10:40 Aug. 4 09:05 0 Aug. 5 15:55 0 Aug. 6 15:50 0



2 2 Aug. 2 14:15 Aug. 4 10:15 0 Aug. 5 09:45 0 Aug. 6 13:55 1 vagrant, mort.

2 3 Aug. 2 14:25 Aug. 4 10:20 crickets Aug. 5 09:55 0 Aug. 6 14:15 0

2 4 Aug. 2 14:45 Aug. 4 10:24 1 vagrant, mort Aug. 5 10:00 0, wrecked by bear, pulled Aug. 6 14:20 0



2 5 Aug. 2 15:10 Aug. 4 10:30 0 Aug. 5 10:20 0, wrecked by bear Aug. 6 14:30 0

3 1 Aug. 3 08:35 Aug. 4 11:00 0 Aug. 5 11:45 0 Aug. 6 12:45 0

3 2 Aug. 3 08:45 Aug. 4 11:05 0 Aug. 5 11:50 crickets Aug. 6 12:50 crickets

3 3 Aug. 3 08:55 Aug. 4 11:10 crickets Aug. 5 11:55 crickets Aug. 6 12:55 crickets

3 4 Aug. 3 09:10 Aug. 4 11:15 crickets Aug. 5 11:58 crickets Aug. 6 13:00 crickets

3 5 Aug. 3 09:30 Aug. 4 11:20 0 Aug. 5 12:25 0 Aug. 6 13:05 0

4 1 Aug. 3 14:45 Aug. 4 12:10 0 Aug. 5 13:30 0 Aug. 6 10:00 0

4 2 Aug. 3 14:55 Aug. 4 12:15 0 Aug. 5 13:35 0 Aug. 6 10:05 0

4 3 Aug. 3 15:10 Aug. 4 12:20 0 Aug. 5 13:40 0 Aug. 6 10:10 0

4 4 Aug. 3 15:25 Aug. 4 12:25 0 Aug. 5 13:45 1 mouse, released Aug. 6 10:15 0

4 5 Aug. 3 15:30 Aug. 4 12:28 0 Aug. 5 13:50 0 Aug. 6 10:20 0

4 6 Aug. 3 15:45 Aug. 4 12:32 1 dusky, mort Aug. 5 13:55 1 vagrant, mort Aug. 6 10:25 0

4 7 Aug. 3 15:55 Aug. 4 12:40 0 Aug. 5 13:57 0 Aug. 6 10:30 0

4 8 Aug. 3 16:05 Aug. 4 12:45 0 Aug. 5 14:10 0 Aug. 6 10:35 0

5 1 Aug. 3 13:10 Aug. 4 12:55 0 Aug. 5 14:22 0 Aug. 6 10:45 0

5 2 Aug. 3 13:25 Aug. 4 13:00 0 Aug. 5 14:25 0 Aug. 6 10:50 0

5 3 Aug. 3 13:40 Aug. 4 13:05 0 Aug. 5 14:30 0 Aug. 6 10:53 0

5 4 Aug. 3 13:55 Aug. 4 13:08 0 Aug. 5 14:35 0 Aug. 6 10:57 0

5 5 Aug. 3 14:05 Aug. 4 13:10 0 Aug. 5 14:35 0 Aug. 6 10:58 0

5 6 Aug. 3 14:15 Aug. 4 13:12 0 Aug. 5 14:40 0 Aug. 6 11:00 1 water shrew, mort

6 1 Aug. 3 10:20 Aug. 4 14:10 0 Aug. 5 08:20 0 Aug. 6 08:15 0

6 2 Aug. 3 10:35 Aug. 4 14:20 0 Aug. 5 08:25 0 Aug. 6 08:20 0

6 3 Aug. 3 10:55 Aug. 4 14:25 0 Aug. 5 08:30 0 Aug. 6 08:25 0

6 4 Aug. 3 11:15 Aug. 4 14:30 0 Aug. 5 08:35 0 Aug. 6 08:35 0

6 5 Aug. 3 11:30 Aug. 4 14:40 0 Aug. 5 08:40 0 Aug. 6 08:40 0

6 6 Aug. 3 11:45 Aug. 4 14:45 0 Aug. 5 08:42 0 Aug. 6 08:45 0



6 7 Aug. 3 11:55 Aug. 4 14:50 0 Aug. 5 08:45 0 Aug. 6 08:55 0

6 8 Aug. 3 12:10 Aug. 4 14:55 0 Aug. 5 08:50 1 dusky, released Aug. 6 09:05 1 dusky, released

6 9 Aug. 3 12:20 Aug. 4 15:10 0 Aug. 5 08:55 0 Aug. 6 09:20 0

6 10 Aug. 3 12:40 Aug. 4 15:15 0 Aug. 5 08:55 0 Aug. 6 09:25 0

Other

Wildlife

Sign:

August 2: Common merganser female with 6 young and 1 American dipper observed at site 1.

August 4: 1 red-legged frog at site 2, 1 barred owl at site 6.

August 5: 2 red-legged frogs at site 2, 1 red-legged frog at site 1.

August 6: 2 red-legged frogs and elk tracks at site 6.

Date post:	03-Feb-2022
Category:	Documents
Upload:	others
View:	1 times
Download:	0 times

China Creek Water Shrew Report - British Columbia

Documents