2018-19 SPLAT Update

This past year we moved a short distance away from roads to work on preventing toads from being trampled on shorelines. We've written about the toad project and our continuing work to mitigate the effects of roads on amphibians in our annual activity report - SPLAT Update for 2018-19.

2017-18 SPLAT Update

We're continuing to monitor the movements of frogs and salamanders through two culverts under Highway 4.  Read an update and learn about some of our other conservation work in the annual newsletter.

SPLAT Update

We have just published our annual newsletter. Check it out!

SPLAT Project in documentary Striking Balance

The SPLAT Project is part of a documentary TV series called "Striking Balance" which explores Canada's UNESCO Biosphere Reserves. The series presents stories about how people interact with nature and several episodes examine the problem of roads for wildlife, including the first episode on the Long Point UNESCO Biosphere Reserve on Tuesday, October 4, 2016 at 9:00 PM on TVO. SPLAT will be part of the Clayoquot Sound episode broadcast the following Tuesday, October 11 at 9:00 PM.  Here's a preview.

You can lead a Treefrog to an underpass, but you can't make it enter...

We tested the effectiveness of our new fence design using wildlife cameras. Two cameras took time-lapse photographs of our fences at the entranceway of the culvert. Surveillance started in September 2014 but we did not get a chance to look through the images until this winter.

For the most part, Northern Red-legged Frogs and Northwestern Salamanders moved without hesitation along the ground at the base of the fences into the culvert. We counted more of them moving through to the other side on peak nights than in previous years.

Northern Pacific Treefrogs, however, did not take the culvert in stride. Our September surveillance period showed dozens of juvenile treefrogs climbing the fences just outside the entranceway.

The young tree frogs were not only good climbers, they also found the weak points where the fences joined the culvert. There was a cut in the fabric on one side, and a bunched fold on the other side. At each spot the overhanging fabric came close to touching the upright wall and gave the climbing frogs a relatively easy escape hatch. It was remarkable to watch so many of them follow the same route around the overhanging lip and over the top!

After realizing the flaws, we braced the overhanging fabric with wood at the joins.

We set out the cameras again in February to see if we had made the fence more escape-proof. Granted, a week of surveillance in February is not the same as a week of surveillance in September. There were no juvenile treefrogs around to test our improvements. Instead, we watched a few adult treefrogs and a salamander climb the fences. We were happy to see that none of them escaped. We will have to wait until next September to see whether our fix is also effective for the next generation of juvenile treefrogs.

Making an escape-proof fence for treefrogs is useful in reducing the number killed by traffic. We also hoped it would guide them to take the safe passageway under the highway. It was too difficult to detect juvenile treefrogs in the grass to track the number that actually did enter and move through the culvert. Perhaps some did, however seeing so many treefrogs climbing begs the question: are culverts effective in connecting habitats across roads for these climbers? 

We're not the first to wonder about this problem… Kenneth Dodd and colleagues showed that culverts and concrete barriers helped other amphibians, but not Green Treefrogs or Squirrel Treefrogs, cross a busy highway in Florida.

Various researchers in Europe have also noted that treefrogs do not readily move through culverts. A Dutch publication on Boomkikkers (the Dutch word for treefrogs) recommends not interrupting connections between breeding and foraging habitats across the landscape when new roads are planned.

The fence installation and effectiveness monitoring were financially supported by the B.C. Ministry of Transportation and Infrastructure, the Clayoquot Biosphere Trust and the Government of Canada, as part of the National Conservation Plan. 

New fences to guide amphibians to the tunnel

We are in the process of replacing the temporary plastic fences that lead frogs and salamanders to the entranceways of the culvert.

Straight-walled plastic sheeting was not ideal. We watched Northern Pacific Treefrogs, juvenile Rough-skinned Newts and Western Red-backed Salamanders climb over it on several occasions, and we frequently needed to patch it (although, it fared surprisingly well over the past 3 years). 

Deciding on a more effective and durable fencing design was a matter of checking out what other folks had tried, and testing to see which options would work for our local species. We chose four different types of materials that have been used to reduce road mortality of frogs and salamanders in other places in Canada. 

We tested to see whether our local species - Northern Red-legged Frogs, Northern Pacific Treefrogs, Northwestern Salamanders and Rough-skinned Newts could be contained within fence enclosures made of each material.

 We compared the frequency of climbing and escape behaviour by each species from each type of enclosure. We observed this behaviour using time-lapse photography with wildlife cameras.

The fabric and both types of solid fencing were more effective than plastic mesh. Northern Pacific Treefrogs escaped from the plastic mesh enclosure 43% of the time, much more often than the other types of enclosures. 

Red-legged Frogs, Northwestern Salamanders and Rough-skinned Newts were able to climb further up the walls of the plastic mesh than the other materials but were rarely able to maneuver around the overhanging lip.

Based on these results and the relative ease of installation along uneven terrain, we chose the polypropylene fabric as the best material for our new fences.

Instead of being straight-walled, the new fence has an overhanging lip, to stop those amphibians with specialized toe pads from climbing over the top!

We are using fabricated plastic wood for the upright stakes and cedar for the top rails. These should last a long time in the rainforest.

The trickiest part of the installation is keeping the fabric smooth. Sections are cut to fit along each segment of the sloping terrain. Overlapping pieces are attached to the rails and stakes with washers, screws, and staples.

The fabric is folded and buried under ground so that salamanders cannot burrow beneath it.

The final touch will be to add a cone of mesh on the backside of the fence every few meters to allow animals to climb over from that direction. We only want the fence to provide a barrier to keep animals from getting onto the road, not off it!

The Habitat Conservation Trust Foundation and Clayoquot Biosphere Trust provided funding to test different types of materials. Support for building the new fences is from the British Columbia Ministry of Transportation and Infrastructure. 

Of course, we are now thinking about ways to ensure that the new fencing will work as intended. We will continue to monitor amphibian movements through the tunnel and devise a way to see what happens when frogs and salamanders encounter the fence! 

Yesterday, we were delighted to show our new fence design to a film crew for a documentary series called “Striking Balance”. The SPLAT project will be included as part of their production on how people are working to find innovative approaches to living in harmony with nature in the 16 UNESCO Biosphere Reserves across Canada. 

Project recognized for contributing to conservation!

The Habitat Conservation Trust Foundation, one of our major funders, presented us with an award for constructing the amphibian underpass system. The award recognizes the value of providing safe passage routes for amphibians and other wildlife under highways. In accepting the award, we acknowledge the B.C. Ministry of Transportation and Infrastructure and many local community members. Without their support, the tunnel installation would never have happened.

To see how we've shared our project as an example of conservation-in-action check out the links on the sidebar under "Sharing the SPLAT story".