Ryder Lake Amphibian Protection Project 2017fraservalleyconservancy.ca/wp-content/uploads/2018/10/RLAPP-201… · Amphibians are one of the most common vertebrate species killed on

Ryder Lake Amphibian Protection

Project 2017

March 2017

Sofi Hindmarch

Project Coordinator

Fraser Valley Conservancy

Fraser Valley Conservancy RLAPP 2017 Page 2 of 37

ACKNOWLEDGEMENTS

This project was made possible with funding provided by the Habitat Conservation Trust Foundation.

Additional funders who supported this project include: Habitat Stewardship Program, Lafarge Canada,

Vancity, TD Friends of the Environment Foundation, and The Langley Concrete Group.

We would also like to thank the numerous volunteers and staff who assisted with road surveys, fencing

installation, and data analysis. Kendra Morgan volunteered many hours to complete time lapse photo

analysis and provided ongoing advice and mentorship.

The support of the local community and the City of Chilliwack was critical to the success of this project. We

are very grateful to the local landowners who allowed us to install directive amphibian fencing on their

properties.

The Fraser Valley Conservancy recognizes the Habitat Conservation Trust Foundation and anglers, hunters,

trappers and guides who contribute to the Trust, for making a significant financial contribution to support

the Ryder Lake Amphibian Protection Program. Without such support, this project would not have been

possible.


TABLE OF CONTENTS Acknowledgements ................................................................................................................................2

Executive Summary ................................................................................................................................4

INTRODUCTION......................................................................................................................................4

Species Information ............................................................................................................................5

History of the Project ..........................................................................................................................7

GOALS AND OBJECTIVES .........................................................................................................................9

STUDY AREA.........................................................................................................................................10

METHODS ............................................................................................................................................11

(Objective 1) Time lapse photography in the amphibian crossing structure ..........................................11

(Objective 2) Assess directional fencing design for weaknesses ...........................................................11

(Objective 3) Assess reductions in road mortality associated with crossing structure and fencing ..........12

RESULTS...............................................................................................................................................14

(Objective 1) Time lapse photography in the amphibian crossing structure ..........................................14

(Objective 2) Assess directional fencing design for weaknesses............................................................18

(Objective 3) Assess reductions in road mortality associated with crossing structure and fencing ..........20

DISCUSSION .........................................................................................................................................24

CONCLUSION .......................................................................................................................................27

LITERATURE CITED ................................................................................................................................28

Appendix A: Average number of toad per survey plot 2014-2016 ............................................................29

Appendix B: Fencing installation and design for Sub-adult Western toad migration 2016..........................30

Appendix C: Fencing installation and design for adult amphibian migration 2017. ....................................35


EXECUTIVE SUMMARY

The Ryder Lake Amphibian Protection Program (RLAPP) was initiated by the Fraser Valley Conservancy in

2008 to address the high mortality of amphibians on Elk View, Ryder Lake, and Huston road in Chilliwack,

BC. In particular, local landowners were concerned about the large number of sub-adult Western Toads

being run over by cars during their annual mass migration in the summer. Amphibians world wide are

commonly killed on roads during their seasonal migrations to and from breeding ponds. Consequently, a

diverse range of engineering solutions have been attempted to help amphibians cross safely under roads.

The RLAPP started with toad rescue events and road closures, but a permanent solution that would allow

both people and amphibians to safely use this roadway was quickly identified as the only long term

solution for this issue. In 2014, 57 permanent plots were established and surveys were initiated to count

migrating adult and sub-adult toads crossing the road at different locations. An amphibian crossing

structure was designed in 2014, and the final product was installed under Elk View road in 2015.

Temporary fencing is set up annually to direct migrating amphibians to the crossing structure.

When compared to 2014 pre-construction results, the 2015 data showed a significant reduction in the

number of sub-adult toads found in four of the eight permanent road plots where fencing was installed, and

in 2016 there was a significant reduction in two of the corresponding plots. The total sub-adult emigration

in 2016 was much smaller when compared to previous years, so this may also be a factor in the plot

results. Time-lapse photography in the crossing structure in 2016 documented a total of 34,915 sub-adult

toads using the crossing, compared to 11,688 in 2015. This is likely the result of improved methodology

and timing; data from future analyses will use the new methods and will therefore be more comparable.

The adult amphibian fencing for spring migration to the breeding pond appears to be quite effective in

reducing the number of amphibians crossing the road along the fenced section. Data from the spring 2017

road surveys is still being collected and initial results are limited. However, time-lapse photography from

the crossing structure during the spring migration to date has yielded a total of 58 amphibians, including

39 toads. By comparison, last year 36 amphibians (31 of which were toads) were recorded using the

structure during the spring migration.

Research into the effectiveness of the amphibian crossing structure in the community of Ryder Lake will

continue over the next several years. Initial results appear positive and ongoing adaptive management of

the existing fencing systems will continue. The Fraser Valley Conservancy plans to continue to work with

our partners and the local community to design and install long-term permanent fencing solution.


INTRODUCTION

Roads are a common feature of a human developed landscape and have a variety of impacts on wildlife

including directly causing mortality. Amphibians are one of the most common vertebrate species killed on

roads (Miklós 2003, Dodd et al. 2004). The seasonal migration of amphibians, from foraging habitats to

ponds and wetlands for breeding, often requires them to cross roads. This puts these species at high risk of

mortality from vehicles and can also pose a danger to motorists when they cross in large numbers. In

addition to direct mortality, roads can also fragment habitats and cause genetic isolation both of which

increase the risk of species going extinct (Miklós 2003). A variety of engineering solutions have been

attempted across the world to reduce amphibian road mortality including a variety of crossing structure

systems. These systems typically consist of a culvert and associated fencing guidance system (Osvaka et al.

2004). Studies of these systems have shown various levels of success and recommendations have been

collated for the optimal systems for allowing amphibians safe passage under roadways (Fahrig and

Rytwinski, 2009; Miklós 2003, and Osvaka et al. 2004).

Many Western toads, and other amphibians, are killed on roads surrounding a breeding pond in Chilliwack,

BC. The Fraser Valley Conservancy, in collaboration with a variety of partners, installed an amphibian

crossing structure in 2015. This report aims to analyze the effectiveness of the installed crossing structure

in reducing road mortality of amphibians at this location.

Species Information The Western Toad (Anaxyrus boreas) is a large warty amphibian that is widespread throughout British

Columbia. Despite widespread occurrence, this species has been listed as of Special Concern by the

Committee on the Status of Endangered Wildlife in Canada (COSEWIC) and pursuant to the Species at Risk

Act (SARA). The Western toad has experienced abrupt and significant declines throughout the United

States and on Vancouver Island. Habitat fragmentation, habitat loss, susceptibility to pesticides and other

chemicals, and disease are all factors that likely linked to these declines. This species, like all native

amphibians, is protected by the Wildlife Act in B.C. making it illegal to kill or hold this species in captivity

(Wind and Dupuis 2002).

Western toads have dry bumpy skin and usually have a pale cream to yellow stripe down their back. They

also have conspicuous parotid glands behind their eyes that store a mild white poison (Figure 1). These

amphibians have diverse colour morphology and can be green, red-brown, black or any variation in

between (see Figure 2) (B.C. Frogwatch Program 2016). Their ventral surface is pale and mottled and has a

patch of pelvic skin that allows them to absorb moisture from the environment. The life expectancy of this

species is between 9 and 11 years (Wind and Dupuis 2002).


Figure 1: Western toad. Figure 2: Sub-adult Western Toad colour morphology.

Western toads are explosive breeders meaning that they congregate in large numbers in the spring to

compete for mates and breed over a short time, usually 1-2 weeks. Breeding occurs in shallow waters of

ponds, stream or lake margins, ditches and even road ruts. Western toads have strong site fidelity and will

return to the same location for breeding year after year. Females mature when they are 4-5 years old and

lay between 5,000 and 16,500 eggs in a long double string (B.C. Frogwatch Program 2016).

Males mature at age 3 and are generally smaller than females. Males compete with each other to enter

amplexus with females. Amplexus is the mating position of amphibians where a male climbs onto a

female’s back and holds on using nuptial pads on his thumbs, until eggs are released. Male toads may

vocalize a release call, a quiet chirping sound, if he is grasped in amplexus by another male.

Figure 3: Congregated Western toad tadpoles in the breeding pond at Ryder Lake (2010).

Embryos usually develop and hatch in 3-12 days. Metamorphosis from tadpoles is usually complete within 3

months and is dependent on water temperatures. Tadpoles are small and black with a tail fin that does not


extend past the tail which distinguishes this species from other frogs. Tadpoles congregate in large

synchronized schools that swim and feed together (see Figure 3). Near the completion of their

metamorphosis they congregate in warm shallow margins and complete their metamorphosis. Tiny

‘toadlets’ migrate en masse away from the wetland and towards forest, grassland, and other moist

terrestrial habitats where they spend the majority of their lives (Wind and Dupuis 2002).

History of the Project The Ryder Lake Amphibian Protection Program (RLAPP) was created by the Fraser Valley Conservancy

(FVC) in 2008. This program was initiated with the help of local landowners in Ryder Lake who wanted to see

a reduction in road mortality of Western Toads during their annual sub-adult emigration from the breeding

pond. The program started with toad rescue events in 2008 and 2009 where sub-adult toads (“toadlets”)

were collected in buckets and carried across the road. A summary of actions undertaken by the FVC to

reduce sub-adult road mortality are detailed in table 1. Road surveys for adult amphibians were commenced

in 2010 and collected data on the Western toad (Anaxyrus boreas), Northern red-legged frog (Rana aurora),

Pacific chorus frog (Pseudacris regilla), Northwestern salamander (Ambystoma gracile), roughskin newt

(Taricha granulosa), and long-toed salamander (Ambystoma macrodactylum). Number and seasons of

surveys are listed in Table 2.

Table 1: A summary of actions undertaken by the Fraser Valley Conservancy.

Year Migration Dates # Observed Action taken by the FVC

2008

2009 2010

2011

2012

2013

2014

2015

2016

July 21 – 26

July 8 - 13 July 28 – August 6

July 25 - 29

Unknown

Unknown

July 8 – 28

June 22 –9

July 7 –20

41,931

39,220 10,000s

NA

Very few

NA

~100,000

>11,9001

>47,2001

Toad rescue event with over 150 volunteers. Toad rescue event and road closures July 11, 12, 13.

Partial road closures July 23-29.

Flagger controlled road closure.

Ready for road closures but too few sub-adults migrating

to warrant closure.

Voluntary detour signs installed.

Voluntary detour signs and monitoring completed.

Toad crossing structure installed (June 1-4) and fencing

installed to direct amphibians to crossing structure.

Voluntary detour signs installed and monitoring

completed.

Fencing installed June 15th to direct amphibians to

crossing structure. Voluntary detour signs installed and

road surveys conducted between July 7 – 20.

1. # observed includes all sub-adult toads detected during road surveys and total counted passing through crossing structure from camera

analysis.


Table 2: Summary of adult road surveys from 2010 to 2016 (value in brackets is percent alive).

Year # Spring Surveys # Fall Surveys Total # Amphibians Observed Total # Western Toads

2010

2011

2012

2013

2014

2015

2016

17

17

11

2

22

9

6

0

0

0

0

2

4

2

716 (43%)

442 (30%)

371 (43%)

156 (18%)

1122 (37%)

437 (45%)

141 (28%)

264 (52%)

127 (35%)

150 (52%)

56 (13%)

268 (47%)

135 (44%)

24 (17%)

Early in the project, it was recognized that a long-term solution was needed at this location to allow Western

toads and people to exist in harmony. Road closures are expensive to enforce and have strong opponents in

the community. Rescue events were dangerous for volunteers working on the road. In addition, picking up

amphibians and transporting them in bucket may cause injury to the smaller amphibians and disorientation

from being transported in buckets which may cause them going back down on the road.

The FVC began exploring alternatives including a permanent amphibian crossing structure. In 2014, an

agreement was made with Lafarge Canada to provide in-kind construction support for a permanent crossing

structure. Engineering drawings were developed and permits acquired from the City of Chilliwack. The

Langley Concrete Group built and donated the culvert pieces. The final design for the crossing structure was

a box culvert (0.91m height x 1.83m width x 12m length) with three man-hole cover grates (0.63m

diameter). These grates are intended to increase the amount of light, moisture, and air passage through the

crossing structure based on recommendations made by other projects (Miklós 2003).

Installation of the crossing structure was completed from June 1-4, 2015, just in time for the summer

migration of sub-adult Western toads. The location of the crossing structure was determined based on

criteria from the City of Chilliwack Engineering Department and the location where the most adult

amphibians are found on the road based on 5 years of road survey data. Consideration was also given to

where sub-adult Western toads were seen crossing the road but no scientific data was available.

Directional fencing to guide the Western toad towards the crossing structure is installed in the spring for the

adults migrating to the wetland and then in the summer for the sub-adults emigrating from the wetland.

Community volunteers assist with the installation of fencing. Details for the design of the fencing for sub-

adult Western toads are in Appendix B, and details for adult fencing are in Appendix C.


GOALS AND OBJECTIVES

The goal of the Ryder Lake Amphibian Protection Project (RLAPP) is to reduce amphibian mortality along

Elk View, Ryder Lake, and Huston Roads through the development of an amphibian crossing structure and

additional safe amphibian crossing routes. This project also aims to maintain and promote community

involvement in this conservation effort. The primary goal of the RLAPP in the 2016-2017 funding year is to

evaluate the effectiveness of the new crossing structure. Specific objectives of this project include:

• Evaluate amphibian use of the installed crossing structure;

• Assess directional fencing design for weaknesses;

• Assess reductions in road mortality associated with crossing structure and directive fencing.


STUDY AREA

This project is based in the community of Ryder Lake in Chilliwack, BC. Ryder Lake is a small farming

community located on the northern end of the Cascade mountain range. The northern slope of the

Cascade Mountains transitions down towards the City of Chilliwack. The biogeoclimatic subzone

represented in this area is the Coastal Western Hemlock dry maritime (CWHdm). The study occurs along a

3km section of Ryder Lake, Huston, and Elk View Roads in Ryder Lake, BC (see Figure 4). This area was

chosen for study based on local interest in the sub-adult Western toads migrating from the productive

breeding pond at the center of the survey route. This breeding pond was created by beaver dam activity in

the 1950’s, it remains wet year-round and is at approximately 230m in elevation.

Figure 4: Map of breeding pond and amphibian survey route in Chilliwack, BC.


METHODS

(Objective 1) Time lapse photography in the amphibian crossing structure To assess the number of amphibians using the crossing structure, a Reconyx PC900 Hyperfire Professional

Covert Camera Trap was installed in the crossing structure. The camera was programmed to take photos

every minute as well as when the infrared sensor was triggered.

1.1 Time lapse photography of crossing structure for sub-adult emigration from wetland

For the sub-adult emigration photos were taken during peak migration periods from 4:00 am to 11:59 am

and from 4:00 pm to 11:59 pm. The camera was set on the ground in the middle of the crossing structure

pointing west towards the wetland. On the ground in front of the crossing structure we placed a white

piece of plastic cloth so that it would be easier to see the toads as they migrated through the crossing

structure. The camera was mounted in the crossing structure on July 7, 2016, as this is when sub-adult

Western toads were staging above the wetland, and removed on July 20th after the completion of the

emigration. Photographs were analyzed individually and number of amphibians, species, date, time, and

temperature were recorded. The number of sub-adult toads per photograph were counted. We also

assessed whether the same toad was seen on several pictures and controlled for this when summarizing

the data. A t-test (two sample assuming unequal variance) was used to compare morning and evening

time-lapse monitoring sessions for sub-adult toads.

1.2 Time lapse photography of crossing structure for adult emigration from wetland

For the adult amphibian emigration from the wetland in the fall photos were taken for the entire 24-hour

period. The camera was set on the ground in the middle of the crossing structure pointing west towards

the wetland. The camera was installed from September 17th to October 29th, 2016. Photographs were

analyzed individually and number of amphibians, species, date, time, and temperature were recorded. We

also calculated the length of time each amphibian was observed in the tunnel, based on the number of

photos taken of each individual (i.e. one photo is taken every minute).

1.3 Time lapse photography of crossing structure for adult migration to wetland

For the adult amphibian migration to the wetland in the spring photos were taken between 5:30 pm and

6:59 am. The camera was set on the ground in the middle of the crossing structure pointing east in order

to capture the adult toads migrating towards the wetland. The camera was installed on March 12th, 2017

and the monitoring is ongoing. Similar calculations as described in 1.2 will also be done for the spring data.

(Objective 2) Assess directional fencing design for weaknesses

2.1 & 2.4 Fence surveys for amphibians (sub-adult and adult)

During road surveys for both sub-adult (objective 2.1) and adult (objective 2.4) amphibians, the fence line

was walked by surveyors to observe behaviour of amphibians approaching or walking along the fence. For

the sub-adult surveys, short videos were taken of the toads moving along the fence. We also assessed the

fence for weaknesses, where sub-adult toads were escaping underneath the fencing, and mend fence

where needed. During the adult fence surveys, species and location was noted. Objectives 2.2, 2.3 and 2.5


0.5m

1m

0.5m

Breeding Pond

Plot

1

Plot

2

camera and video monitoring methods have been removed from the project as they are not feasible at this

site. We have found the visual monitoring of the fence line sufficient to monitor the effectiveness of the

fence.

(Objective 3) Assess reductions in road mortality associated with crossing structure

and directive fencing

3.1 Road surveys for sub-adult Western toads

A total of 59 survey plots were laid out along the existing amphibian survey route in Ryder Lake. The survey

route is 3km long and encompasses parts of Elk View, Ryder Lake, and Huston Roads (Figure 4). Plots are

located 50m apart. Each plot was permanently marked on the road with paint and given a unique number.

During each survey a 0.5m x 1m rectangle (made out of wood) was placed at each marker in two locations.

Plots were placed on the breeding pond side of the road 0.5m from the centerline. Two plots were

counted at each survey locations set diagonally from each other (see Figure 5).

Figure 5: Plot layout showing road and centerline.

In each plot all live and dead amphibians were recorded as well as time of monitoring. Live amphibians

were moved to the side of the road in their direction of travel. Any dead amphibians were scrubbed off the

road using a barbeque brush so they would not be double counted. We also counted the number of live

Western toad between each plot and moved live individuals to the side of the road away from the

wetland. Dead sub-adult Western toads between each plot were only counted during the first survey as it

is hard to discern additional road mortality during subsequent surveys. Surveys were conducted in the

morning and/or evening, starting around 8 am and 6 pm respectively.

A two-tailed t-test was performed comparing the average number of sub-adults found per survey in each

plot between 2014 (before crossing structure) and 2016 (after crossing structure). Equal or unequal

variance was determined based on an F-test in Excel.


(Objective 3.2 & 3.3) Road surveys for adult amphibians Road surveys for live and dead adult amphibians were conducted following standard Resource Inventories

Standards Committee procedures (MELP 1998). Surveys were completed after sunset on days with

appreciable precipitation and preferentially on nights with evening rain. Two to four surveyors walked a

prescribed 3km route, backtracking along all sections (see Figure 4). Surveyors spread out across both

lanes of the road and walked at a medium pace scanning the road with headlamps. For each amphibian or

amphibian carcass observed the following data was collected: species; whether the specimen was alive or

dead; gender (when possible); age class; and direction of movement (generalized as towards or away from

central breeding pond). A GPS point was taken using a Garmin CSX60. Dead amphibians were moved off

the road to prevent double counting as surveyors returned along the survey route. Live amphibians were

carefully transported off the road in the direction of their travel to avoid double counting and prevent

vehicular mortality. A clean nitrile or vinyl glove was used for each individual to prevent disease

transmission and protect the amphibians from oils or lotions on hands in accordance with Wildlife Permit

SU16-227002.

Weather data was collected at the beginning and end of each survey including percent cloud cover (0%, 1-

49%, 50-99%, 100%); precipitation category (Misty drizzle, Light Rain, Rain, Heavy Rain); ranking from

Beaufort Wind Scale, and temperature. Names of the surveyors were recorded as well as start and end

time of the survey.

Data collected was analyzed for number of amphibians identified per survey, percent of each amphibian

species found alive and average number of amphibians per survey and km. In addition, the average

number of amphibians per survey was calculated for the area where fencing was installed and compared

with historical data collected in the same area before the fencing and crossing structure were installed.


RESULTS

(Objective 1) Time lapse photography in the amphibian crossing structure Time-lapse photography was used to monitor the crossing structure in the three migratory seasons. In

total, 38, 874 photographs were taken and analyzed (Table 3). Over 120 volunteer hours were spent

analyzing the photographs.

Table 3: Number of photographs and average number of amphibians from 2015-2017. Field of view refers to the positioning of

the camera in the crossing structure, i.e. “Large” horizontal view versus “Small” vertical view (no longer in use).

Field of View

Life Stage Season # Photos # Amphibians

Large Small

Small

Large

Sub-adult Sub-adult

Adult

Adult

June 25 to June 30, 2015 June 30 to July 17, 2015

Sept 24 to Oct 16, 2015

Feb 15 to Mar 26, 2016

669 16,771

21,566

30,396

10,886 802

9

36

Large Sub-adult July 7 to July 20, 2016 13,119 34,915

Large Adult Sept 16 to Oct 25, 2016 6392 27

Large Adult March 12 to April 5, 2017 19,363 58

TOTAL 10,8276 46,733

To date, 46,733 amphibians have been observed passing through the crossing structure, including Western

toads, Northern red-legged frogs and salamander species. The majority of amphibians observed were sub-

adult Western Toads (Table 4, Figure 6 and 7).

Table 4: Number of amphibians observed in the crossing structure by species 2015-2017.

Species Number Observed

Unknown frog species 15

Northern Red-legged frog 10

Salamander species 16

Western toad 89

Sub-adult Western toad 46603


Figure 6: Sub-adult Western toads in crossing structure (Summer 2016).

Figure 7: Adult female Western toad in crossing structure (Spring 2017)


Contrary to 2015, when significantly more sub-adult toads were seen between 4am and 12pm (morning)

versus 4pm and 12 am (evening), no such differences were detected in 2016 (t=0.72, P=0.47, df= 34952,). The

number of sub-adult Western toads seen per day was analyzed and results are shown in Table 5.

Table 5: Number of sub-adult Western toads observed crossing through a crossing structure in 2016.

Date Total # Toads Total # Minutes Average Toad/Hour

July 7, 2016

July 8, 2016

July 9, 2016

July 10, 2016

July 11, 2016

July 12, 2016

July 13, 2016

July 14, 2016

July 15, 2016

July 16, 2016

July 17, 2016

July 18, 2016

July 19, 2016

July 20, 2016

1032

6474

9650

5315

4824

3475

1459

576

740

659

343

248

109

11

585

1011

1008

999

1008

993

1023

993

996

996

999

999

999

510

106

385

574

319

287

210

86

35

45

40

21

16

7

1

Total 34915 13119 160


18

23

10

6

8 8

6

2 21 1 1

0

5

10

15

20

25

1 2 3 4 5 6 7 8 10 14 23 61

Nu

mb

er

of

toa

ds

Number of minutes in crossing structure

The average time spent in the crossing structure was calculated for adult Western toads during their

migration and emigration to and from the wetland. The field of view for the camera was approximately 7m

which is 58% of the crossing structure length. It was not possible to identify species seen as eye-shine at the

furthest point from the camera. Toads were observed in 1–61 photos meaning that they spent between 1

and 61 minutes in the camera’s field of view while crossing through the crossing structure (Figure 8). The

average time spent in the camera’s field of view was 4 minutes. However, 60% of the toads spent 1-3

minutes in the crossing structure.

Figure 8: Total time individual adult Western toads were seen in the crossing structure spring 2016-2017 (n=86).


OBJECTIVE 2) ASSESS DIRECTIONAL FENCING DESIGN FOR WEAKNESSES

2.1 Fence surveys for sub-adult Western toads Approximately 350m of directional fencing was installed on June 15, 2016 to direct sub-adult Western

toads emigrating from the wetland through two safe crossing routes (Appendix B). Emigration of sub-adults

was observed on July 7th. During the emigration we walked the fence daily to assess for weaknesses. The

majority of the sub-adult Western toads were observed following the installed amphibian directional

fencing.

However, a couple unanticipated fencing failures did occur. On July 8th, many sub-adult Western toads

were found to be migrating north of the fencing, consequently missing the crossing structure and the road

culvert (route 2, see Appendix B). To ensure that these displaced sub-adult toads were also directed

towards the toad crossing structures, the fencing in the hay field was moved north alongside Ryder Lake

Rd. As well, additional fencing ~ 50m was installed just south of the intersection along Elk View Rd on July

10th. The new fence stopped displaced sub-adult toads from crossing the intersection and instead they

followed the new fence line towards an installed ramp (Figure 9) which allowed them to climb back over to

the original fencing directing them to the main crossing structure. On July 9th, it was observed that ~ 15m

of the fencing following the eastern portion of the hayfield was not securely fastened to the ground as

several sub-adult toads were able to escape underneath the fencing. Re-attaching this section of the

fencing to the ground and carefully surveying the length of the fence before each road survey significantly

reduced the number of toads found on the wrong side of the fence. Fencing was removed on July 26, 2016

after the emigration of sub-adult Western toads was completed.

Figure 9: Sub-adult Western toad emigrating up along

toad ramp which connects with toad fencing facilitating

the sub-adult toads back to the right side of the fence.


2.4 Fence surveys for adult Western toads On February 26th 2017, approximately 125m of fencing was installed on the eastern side of Elk View road

to direct adult amphibians migrating from their forested habitats to the wetland for breeding (Appendix C).

To date, four spring road surveys have been conducted for adult amphibians after fencing installation. One

red-legged frog was observed walking along the fence line on March 12th.

Figure 10: Fencing angled away from road and silt material attached using staples.


(Objective 3) Assess reductions in road mortality associated with crossing structure

and directive fencing

3.1 Road surveys for sub-adult Western toads

Sub-adult Western toads started migrating on July 7, 2016. As of July 20, 2016 the migration was finished

and no surveys were done after this date. In total, 9 road surveys were completed resulting in total 38

dead and 0 alive sub-adult Western toads were observed in the plots. The average number of live toads

seen in between plots was on average 5.4 toads per survey.

Significant differences (p<0.05) between average number of sub-adult toads per plot in 2014 compared to

2016 were found for 5 of the 57 plots 40, 42, 45, 46 and 47) (Figure 11, 12, Appendix A). For all the plots,

the average number of toads found in 2016 was significantly lower when compared to 2014. Two of these

plots (40 and 42) were found behind the installed fencing. Figure 11 shows the average numbers of

amphibians per plot from 2014 - 2016 while Figure 12 shows the locations of each sub-adult plot and

where fencing was installed for the sub-adult migration.

Figure 11: Comparison of average numbers of sub-adult Western toads found in permanent plots from 2014 to 2016. * specifies

plots which had significant lower average number of sub-adult toads when compared to 2014.


Figure 12: Location of each sub-adult Western toad plot as well as location of directional fencing installed for the sub-adults in

2016. * specifies plots which had significant lower average number of sub-adult toads when compared to 2014.


Northwestern

Salamander…

Long-toed

Salamander

3%

Western Toad

15%

Pacific Chorus Frog

44%

Western Red-backed

Salamander

0%

Northern Red-

legged Frog

25%

Roughskin Newt

8%

Common Garter

Snake

5%

(Objective 3.2 & 3.3) Road surveys for adult amphibians In total, 7 amphibian road surveys were completed between April 22, 2016 and April 5, 2017. Thirty-three

person hours of surveying was completed with the help from 7 volunteers. A total of 210 amphibians, alive

and dead, were identified along the 3km survey route. On average, 30 amphibians were seen per survey or

approximately 10 amphibians/km of survey. The total number of each species as well as percent alive is

shown in Table 6. Tables 7 and 8 show the total numbers separated by season. Figure 13 shows the total

species composition in percent.

Table 6: Total number of amphibians observed during road surveys in the spring and fall 2016, and spring 2017.

Species # Alive # Dead Total Alive

Long-toed salamander 4 4 8 50%

Western toad 3 13 16 19%

Pacific Chorus frog 49 60 109 45%

Common Garter snake 0 6 6 0%

Northern Red-legged frog 22 31 53 42%

Rough Skin newt 2 15 17 12%

Unidentified 0 1 1 0%

TOTAL 80 130 210 38%

Figure 13: Species composition of adult amphibians found during Ryder Lake road surveys between 2015-2017(n= 498).


Table 7: Total number of amphibians observed during road surveys in spring 2015-2017 (n=13).








TOTAL 133 189 322 41%

Table 8: Total number of amphibians observed during road surveys in fall 2015-2017 (n=6).


Northwestern salamander 1 1 2 50%




Western Red-backed salamander 0 1 1 0%




Unidentified 0 1 1 0%

TOTAL 65 111 176 26%

Directional fencing was installed along Elk View Road on February 26, 2017 (Appendix C). Surveys

completed in February and March of 2016 (n=5) and 2017 (n=3) were compared to surveys completed in

the same months in 2015 (n=6), before the toad crossing structure was installed (Table 9). Fencing was

installed over 12m of the 3km survey route which is 4% of the survey route. The average number of

amphibians detected on road where fencing has been installed has dropped from 4 to 1.7 amphibians per

survey.

Table 9: Average number of amphibians per survey from 2015-2017 in February and March.

Year Average Along road where

fencing was installed

Along road where

fencing was not installed

2015 40 4 36

2016 13 2.2 10.8 2017 36 1.7 34.3


DISCUSSION

The sub-adult toads started emigrating on July 7th, 2016, which was 2.5 weeks later than 2015. This

difference is likely correlated with the weather, as we had an unusually warm spring in 2015. Emigration

typically occurs in July. In total 34,915 sub-adult toads were documented, with time-lapse photography,

emigrating through the crossing structure between July 7th and July 20th, 2016. This was almost three

times higher than the number of toads documented in 2015 when a total of 11,688 sub-adult toads were

counted emigrating through the structure. We attribute the higher number of toads in 2016 to the camera

angle, as the camera was changed from a vertical to horizontal orientation, so the frame captured a larger

area of the crossing structure. In addition, the camera was installed well in advance of the emigration

which ensured that we had a more accurate count of the total number of sub-adult toads emigrating

through the crossing structure. Road surveys for sub-adult toads commenced on July 9th, and nine surveys

documented a total of 38 dead and zero live individuals in the 59 plots. This was substantially lower than

2015 when 212 (n=9 surveys) sub-adult toads were documented and 2014, pre-install of crossing structure,

when 1032 sub-adult toads were counted (n=31 surveys). The low numbers documented in 2016, could be

due to a smaller emigration, which was expected based on the low number of migrating adult toads

documented in the spring of 2016. Amphibian populations are known to fluctuate annually, and they are

also vulnerable to stochastic events such as changes in environmental conditions, disease and predation

(Marsh and Trenham 2001). The installation of fencing well in advance of the sub-adult emigration and

continued efforts to improve the fencing throughout the emigration period, also reduced the number of

sub-adult toads on the road. In the fall of 2016, a total of 28 adult toads were documented emigrating

from the wetland (time-lapse photography n=19, road surveys n=9 dead) and to date this spring a total of

41 adult toads have been documented migrating to the wetland (time-lapse photography n=39, road

surveys n=2 dead).

Installing the camera ~ 5cm above the ground in the crossing structure facing horizontally towards the

wetland ensured that the camera frame captured a larger area of the crossing structure. This along with

placing a white piece of plastic cloth on the ground in front of the camera increased our ability to detect

and count sub-adult toads using the structure. However, the width of the camera lens still precludes us

from getting a good view of the concrete sides, especially 1-2m from the camera itself, so we likely missed

counting sub-adult toads walking right up against the concrete wall. Another potential error when using

time-lapse photography is double-counting toads that have not cleared the field of view in the one minute

photo timeframe. Overall, we expect that these errors are minimal relative to the numbers of sub-adult

toads counted.

Time lapse-photography, as a method, also proved quite useful for monitoring adult Western toads and

other amphibians using the crossing structure and it is an important monitoring method alongside road

surveys. Especially given the adult Western toads’ elusive behavior, combined with their spring migration

and fall emigration spanning over a much longer time-frame when compared to the sub-adult emigration.

So far this spring, we have documented 58 amphibians (39 adult Western toads) migrating to the wetland

through the crossing structure, which is the highest number to date documented in one season.

Corresponding spring road surveys have documented two dead Western toads to date. Time-lapse


photography and road surveys will continue through April to further assess this year’s amphibian

populations. We are pleased with the current camera install, and the results generated from the 2016 and

2017 monitoring of the Western toad sub-adult emigration and adult amphibian migration/emigration to

and from the wetland.

The sub-adult fencing was installed on June 15th, 2016, which was well in advance of the emigration which

started on July 7th. The results indicated the fencing was effective in directing the sub-adult toads towards

the main crossing structure (route 1) and culverts north of the crossing structure (route 2, see Appendix B).

However, there were two unforeseen events that lead to modifications in the first three days of the

emigration. First on July 8th, it became apparent that a large portion of sub-adult toads were migrating

north of the fencing, consequently missing the crossing structure and instead crossing Ryder Lake Rd. The

sub-adult toads have never been documented this far north in the hayfield before, and in order to mitigate

for the change in their emigration route, we moved the fencing in the hay field to the north alongside

Ryder Lake Rd. Additional fencing ~ 50m was also installed just south of the intersection along Elk View Rd

on July 10th. The new fence stopped displaced sub-adult toads from crossing the intersection and instead

they followed the new fence line towards installed ramps which allowed them to climb back over to the

original fencing directing them to the main crossing structure. Second, on July 10th, a large portion of sub-

adult toads were observed breaching the fence line along the eastern portion of the hayfield and

subsequently migrating across Elk View Rd. We identified sections of the fence where the junction

between the bottom of the fence and the ground was not complete and fixed these sections. In addition,

the install of the second fence line just south of the intersection of Elk View and Ryder Lake reduced the

number of sub-adult toads spilling on to the two roads. The main learning outcomes from both incidents is

that it is very important to carefully inspect temporary fencing after it has been installed by volunteers to

ensure that there is absolutely no space for sub-adults to work their way underneath the fencing (i.e. a

finger should not be able to be inserted between the hose and the ground). Furthermore, it stressed the

importance of adopting an adaptive management approach to the fencing alignment during the initial

stage of the sub-adult emigration as there are likely to be slight annual differences in their main emigration

route from the wetland. A simple fencing installation instruction manual is being developed to assist with

volunteer training for future installations. Establishing well-constructed permanent along the road edge at

this site has become a priority for this project moving forward.

The adult fencing for the spring migration was installed on February 26th 2017 and appears to be quite

effective at reducing the number of amphibians crossing the road. In February and March a total of five

amphibians, none of which were toads, were found within the fenced area (n=109 amphibians across

entire survey route). Concurrently, 39 toads were counted using the crossing structure during this

timeframe. To improve upon the water drainage problems found with this fencing last year, we created

small side ditches and added gravel so that the water could flow underneath the fencing; this also reduced

the chances of gaps in the fencing. For both the sub-adult and adult fencing monitoring we found that

visual observation and adjusting the fence immediately while on site was highly effective. We feel this is a

better method than using camera or video monitoring, which was proving challenging to implement.

Therefore, the camera and video monitoring of the fencing has been removed from the project.


The 2016 sub-adult emigration from the wetland was lower than previous years. This was noted by

experienced migration observers and was expected based on the lower number of adults noted migrating

to the wetland in the spring. The lower emigration this year was also reflected in the sub-adult road

survey. In total, only 38 dead sub-adult toads were documented in the plots. Five of the plots had

significant lower average number of toads when compared to 2014 (prior to the crossing structure). Two

of the plots, were found within the fenced area and the three remaining plots were located just south of

the crossing structure and at the end of the fencing along Elk View Rd. The low number of toads

documented in the three latter plots fits the overall trend of the migration this year as relatively very few

sub-adult toads were documented south of the crossing structure when compared to 2014 and 2015. The

significantly lower number of toads documented in plots within the fenced section could also be partially

credited to our quick response to initial failures in the fencing, which ultimately reduced the number of

sub-adult toads spilling on to the road.


CONCLUSION

The amphibian crossing structure was successfully used by at least 35,000 adult and sub-adult amphibians

between April 2016 – 2017. This is almost three times higher than the number of sub-adult toads

documented during the same-period in 2015 – 2016. The horizontal placement of the camera in the

crossing structure and the white cloth on the ground enabled us to get a more accurate count. However,

we also attribute the higher number of amphibians using the crossing structure to the fencing being

monitored daily, and quickly adjusted or repaired as needed to direct the maximum number of amphibians

towards the crossing structure. Ongoing monitoring of the amphibians use of the crossing structure will

continue to guide us in making the fencing as effective as possible.

In the coming year, the Fraser Valley Conservancy plans to test a permanent fencing solution for this site

and will, as part of this, be hosting a meeting with other interest groups, Lafarge Canada and our

government partners to exchange ideas and discuss options for permanent fencing solutions.


LITERATURE CITED

B.C. Frogwatch Program. 2016. “Western Toad.” B.C. Frogwatch Program Species Factsheets. British

Columbia Ministry of Water, Land and Air Protection. 2pp. March 8, 2017.

Dodd, C.K., W.J. Barichivich, and L.L. Smith. 2004. Effectiveness of a barrier wall and culverts in reducing

wildlife mortality on a heavily traveled highway in Florida. Biological Conservation 118:619-631.

Fahrig, L., and T. Rytwinski. 2009. Effects of roads on animal abundance: an empirical review and synthesis.

Ecology and Society 14(1): 21. [online] URL: ecologyandsociety.org/vol14/iss1/art21 (accessed March 23,

2016).

Marsh, D. M., and P. C. Trenham. 2001. Metapopulation dynamics and amphibian conservation.

Conservation Biology 15:40-49.

MELP 1998. Inventory methods for pond-breeding amphibians and painted turtle. Standards for

components of British Columbia’s biodiversity; no. 37. Ministry of Environment, Lands and Parks

Resources Inventory Branch.

Miklós, P. 2003. Amphibian Mitigation Measures in Central-Europe. In 2003 Proceedings of the

International Conference on Ecology and Transportation, edited by C. Leroy Irwin, Paul Garrett, and K.P.

McDermott. Raleigh, NC: Center for Transportation and the Environment, North Carolina State University,

2003.

Ovaska, K., L. Sopuck, C. Engelstoft, L. Matthias, E. Wind. 2004. Best Management Practices for Amphibians

and Reptiles in Urban and Rural Environments in British Columbia. BC Ministry of Water, Land and Air

Protection. Nanaimo. 1-159pp.

Wind, E.I. and L.A. Dupuis. 2002. COSEWIC status report on the western toad Bufo boreas in Canada, in

COSEWIC assessment and status report on the western toad Bufo boreas in Canada. Committee on the

Status on Endangered Wildlife in Canada. Ottawa. 1-21 pp


APPENDIX A: AVERAGE NUMBER OF TOAD PER SURVEY PLOT 2014-2016

Table 10: Average number of toads per survey for each plot in 2014, 2015 and 2016. The p-value from a two sample two tailed t-

test is given. Values that were statistically significant (P<0.05) are identified by an asterix.

Plot # 2014 avg 2015 avg 2016 avg T-test 14 vs 15 P<0.05 (ie sig diff?) T-test 14 vs 16 P<0.05 (ie sig diff?)

1 0.00 0.00 0.00 NA NA NA NA

2 0.00 0.00 0.00 NA NA NA NA

3 0.00 0.00 0.00 NA NA NA NA

4 0.00 0.00 0.00 NA NA NA NA

5 0.00 0.00 0.00 NA NA NA NA

6 0.27 0.22 0.00 0.88 No 0.34 No

7 0.03 0.22 0.00 0.42 No 0.59 No

8 0.13 0.44 0.00 0.51 No 0.49 No

9 0.57 0.33 0.00 0.51 No 0.09 No

10 0.63 0.11 0.00 0.07 No 0.19 No

11 0.13 0.67 0.00 0.37 No 0.37 No

12 0.13 0.56 0.00 0.48 No 0.49 No

13 0.07 0.00 0.00 0.59 No 0.59 No

14 0.23 0.11 0.00 0.47 No 0.31 No

15 0.03 0.00 0.00 0.59 No 0.59 No

16 0.00 0.00 0.00 NA NA NA NA

17 0.00 0.00 0.00 NA NA NA NA

18 0.07 0.00 0.00 0.44 No 0.44 No

19 0.13 0.00 0.00 0.37 No 0.37 No

20 0.10 0.00 0.00 0.47 No 0.47 No

21 0.10 0.00 0.00 0.47 No 0.47 No

22 0.03 0.00 0.00 0.59 No 0.59 No

23 0.03 0.00 0.00 0.59 No 0.59 No

24 0.00 0.00 0.00 NA NA NA NA

25 0.00 0.00 0.00 NA NA NA NA

26 0.20 0.00 0.00 0.15 No 0.15 No

27 0.43 0.22 0.00 0.42 No 0.09 No

28 0.30 0.00 0.00 0.18 No 0.18 No

29 0.67 0.00 0.00 0.07 No 0.07 No

30 2.43 0.00 0.00 0.09 No 0.09 No

31 0.67 0.00 0.00 0.17 No 0.17 No

32 0.03 0.00 0.00 0.59 No 0.59 No

33 0.13 0.00 0.00 0.26 No 0.26 No

34 0.00 0.00 0.00 NA NA NA NA

35 0.10 0.00 0.00 0.47 No 0.18 No

36 0.07 0.00 0.00 0.44 No 0.16 No

37 0.13 0.00 0.22 0.37 No 0.71 No

38 0.60 0.11 0.56 0.02 Yes 0.90 No

39 2.87 0.11 1.11 0.00 Yes 0.13 No

40 1.50 0.22 0.00 0.02 Yes 0.01* Yes

41 0.10 0.11 0.00 0.94 No 0.47 No

42 7.00 0.78 0.44 0.01 Yes 0.00* Yes

43 2.00 0.00 0.22 0.10 No 0.14 No

44 1.63 0.56 0.89 0.09 No 0.34 No

45 1.50 0.78 0.00 0.29 No 0.00* Yes

46 2.40 2.56 0.44 0.88 No 0.02* Yes

47 1.70 4.78 0.11 0.28 No 0.00* Yes

48 1.60 0.78 0.00 0.39 No 0.08 No

49 1.03 0.22 0.22 0.02 Yes 0.14 No

50 0.37 0.67 0.00 0.32 No 0.16 No

51 0.20 0.11 0.00 0.61 No 0.23 No

52 0.20 0.22 0.00 0.93 No 0.38 No

53 0.10 0.78 0.00 0.16 No 0.34 No

54 0.23 1.44 0.00 0.39 No 0.31 No

55 1.40 1.78 0.00 0.75 No 0.17 No

56 0.10 4.56 0.00 0.19 No 0.47 No

57 0.00 0.11 0.00 0.07 No NA NA


APPENDIX B: FENCING INSTALLATION AND DESIGN FOR SUB-ADULT WESTERN TOAD MIGRATION

2016.

The Fraser Valley Conservancy installed amphibian fencing to guide migrating sub-adult

Western toads to the newly installed crossing structures on June 15, 2016. Over 350m of directional

fencing was installed with the assistance of 10 volunteers from Lafarge Canada and the community along

with two FVC staff.

Figure 1: Fencing installation volunteers.

The fencing set-up was designed specifically for the mass migration of sub-adult Western toads that occurs

in this area every year. The topography and land ownership in this area mean that the majority of the

directional fencing is installed and taken down for each migration. Haying of the field needs to be

coordinated with the land manager prior to fencing installation. Therefore, a simple and cost effective

design was required. Silt fence material (black plastic fabric material) was attached to wooden stakes using

a staple gun (Figure 2).


Figure 2: Attaching silt fence material to wooden stakes

Approximately 15 cm of the material was left at the bottom of the fence and attached to the ground . The

preferred method was a garden hose was run along the edge of the material and held in place using

ground staples (Figure 3b), where this was not feasible either soil or gravel was piled on top of the material

(Figure 3a). Both methods prevent sub-adult western toads from crawling under the fencing. Extra

material at the top of the fence was folded over in the direction of the wetland and attached to the posts

creating a pocket to discourage amphibians from climbing over the fence.

A

Figure 3: Using soil (A) and hose/ground staples (B) to attach fence to the ground. Also note how the silt fence material was

folded over at the top to prevent amphibians from crawling over the fence (A)

Fencing was installed to direct the migrating amphibians towards two culvert systems. Amphibians were

directed through the newly installed amphibian crosing structure (route 1) as well as a system of two

existing culverts (route 2). Both routes allowed the amphibians to safely cross Elk View road along their

natural migration routes. Route 2 involved two existing culverts: one under Ryder Lake road and a second

A

B

Silt fencing overlap

Soil attaching fence to

ground.

A

Garden hose and ground

staples attaching fence to

ground


under Elk View road. Fencing was installed inbetween the two culverts to keep the toads moving towards

the second culvert. Toads migrating between the two road crossing routes could choose to move in either

direction to a safe crossing structure. The ends of the fencing not connected to a culvert were curved to

encourage any amphibians moving away from the crossing structures to turn around and head back

towards the safe crossing structures.

Figure 4: Map showing where directional fencing was installed in 2015.

The fencing was attached to the culverts using a combination of fence posts, zap straps, and duct tape

(Figure 5), this is one of the more challenging aspects of the fencing and needs to be done thoroughly to

ensure no gaps.


Figure 5: Attaching fencing to culvert using fence post and duct tape.

Figure 6: Fencing to redirect amphibians following fencing towards the crossing structure entrance.

Figure 7: Fencing from wetland to first culvert of route 2.

Attaching fence

to culvert with

duct tape

Fence post installed

adjacent to culvert


Figure 8: Fencing through forest towards new crossing structure (route 1)

Figure 9: Fencing to direct amphibians between first and second culvert along crossing route 2.

A

Silt fencing overlap


APPENDIX C: FENCING INSTALLATION AND DESIGN FOR ADULT AMPHIBIAN MIGRATION 2017.

The Fraser Valley Conservancy (FVC) installed amphibian fencing to guide migrating adult Western

toads, Northern Red-legged Frogs, and other amphibians to the newly installed crossing structures on

February 26, 2017. At this location, adult amphibians are known to start migrating to breeding locations

in February. However, we do anticipate a later start to the migration due to the atypical cold and snowy

winter we have had on the south coast. Approximately 125m of fencing was installed with the assistance

of 12 community volunteers and 2 FVC staff members.

Figure 1: Fencing volunteers after completing the install!

The fencing was designed as a temporary measure to guide amphibians migrating towards the breeding

wetland to the toad tunnel which allows safe passage under Elk View road. We installed the fencing

along the forest side of the road (opposite the breeding pond) to guide the animals safely through the

tunnel and towards the wetland. The topography and land ownership in this area means that this

fencing must be installed and removed every season. The fencing was installed along the road (in the

right-of-way). We are currently pursuing more permanent solutions; however, until then we will

continue to develop this temporary fencing design.


Figure 2: Digging trench and installing wooden stakes.

Silt fence material (black plastic fabric material) was attached to wooden stakes using a staple gun. A

trench was dug and the bottom 10 cm of the fence was buried in the ground to prevent amphibians,

salamanders in particular, from burrowing under the fence (Figure 2). The fence was angled away from

the road to discourage amphibians from climbing over the top. In addition, the height of the fence on

average is 70 cm to reduce the chance of amphibians crawling over the top (Figure 3).

Figure 3: Fencing angled away from road and silt material attached using staples.


The fencing was attached to the culverts using a combination of fence posts and zap straps (Figure 4).

The ends of the fencing not connected to the toad tunnel were curved to encourage any amphibians

moving away from the crossing structures to turn around and head back towards the safe crossing

structure. This fencing will help prevent the amphibians from crossing back over the road.

Figure 4: Fencing attached to toad tunnel using fence posts and zap straps.

Figure 5: Map showing where directional fencing was installed in 2017.

overlap

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