The boreal forest in central Ontario supports a unique assemblage of endangered turtles, snakes, ungulates, and carnivores This region also harbours the Georgian Bay Biosphere Reserve, a world UNESCO site, that is situated adjacent to the Highway 400/69 corridor under study. Road-wildlife conflicts are well-documented along this highway and concurrent to a several decade-long, phased highway twinning project, the Ontario Ministry of Transportation (MTO) has been installing and monitoring wildlife crossing structures and exclusion fencing for both large and small animals.
From 2011 to 2020, Eco-Kare International was retained to lead and conduct the monitoring component of the wildlife mitigation along 250 km of highway for both cold- and warm-blooded animals on Highway 69. An overview of the monitoring techniques employed, key findings, and lessons learned at a variety of wildlife crossing structures (dedicated and existing drainage culverts), and exclusion fencing are summarized in this presentation.
The large animal fence was a 2.4 m high wire mesh fence that spanned approximately 10 km. The turtle fence was affixed to the bottom of the large animal fence, and was comprised of heavy duty plastic geotextile that was 0.8 m high and 0.2 buried underground. There was a 4.3 km section of highway that was fenced continuously with the turtle fence.
Crossing structures included one overpass, several larger box culverts, a creek-bridge pathway, and three 2.8 m x 3.2 m wide tunnels (large animals and turtles) and adjacent drainage culverts (turtles only). Monitoring consisted of several camera techniques used at structure entrances to capture both warm-blooded (mid to large sized mammals) and cold-blooded (turtle) animal passage. Camera monitoring was standardized and consistent at structures that were compared for wildlife use.
Key findings and conclusions from wildlife crossing structure use is are summarized. Wildlife overpasses are the preferred crossing structure type for all animals including turtles because the structure provides, habitat, and ideal temperatures for cold-blooded animals. Larger underpass tunnels will be used by freshwater turtles, and work best when placed at connected-wetland systems. Larger underpass tunnels with open medians are more likely to provide warmer temperatures for cold-blooded animal passage along highways and additionally provide connectivity for larger mammal species.
Monitoring programs are being funded, but routine maintenance and recommendations for improvements are not. Oversight is required during installation to ensure exclusion fence is adequately installed to design specifications and this will reduce ongoing maintenance requirements.
Long-term monitoring plans greater than five years are required especially for turtles, because of the low annual use at each structure, the challenges of monitoring cold-blooded animals in water, and the ‘lag period’ for use by turtles.