29 federally identified species at risk will be impacted if Highway 413 is built.

Birds that would be negatively impacted by Highway 413 include the Bank Swallow, the Red-headed Woodpecker, and the Short-eared Owl.

Other species at risk if Highway 413 is built include the Blanding's Turtle and the Reside Dace - a rare minnow.

Highway 413  would push endangered species in the area even closer to the brink, while we’re in the midst of a global biodiversity crisis. Some scientists are referring to this period as the sixth great extinction – and Highway 413 would accelerate that.

- Keith Brooks, Programs Director, Environmental Defence


Highway 413 is a proposed mega-project that would fuel more urban sprawl, put more greenhouse gas pollution in our atmosphere, cut through the Greenbelt, destroy fertile farmland and pave over important species habitat, pushing threatened species even closer to the brink.

To better understand the risk to endangered and threatened species, Environmental Defence commissioned biologists at the University of Guelph to review available information and identify what at-risk species have been sighted near the proposed route for the highway, and how the construction of the highway would impact the future of each at-risk species in the region.

The analysis revealed that Highway 413 would have some serious impacts to natural areas and species. If built, the highway would: 

  • Negatively affect a minimum of 29 species listed under the federal Species at Risk Act
  • Cross an estimated 132 streams and rivers, many of these fish-bearing and at least  quarter of them being cool water streams, supporting important aquatic communities. 
  • Result in the loss of 400 acres of Greenbelt and 2000 acres of farmland, much of it the headwaters of rivers and streams.
  • Compromise the ecological integrity of the Nashville Conservation Reserve, an important protected area rich in biodiversity and one of the most intact forested areas in the GTA. 
  • Cumulative effects from urban sprawl encouraged by the highway are expected to result in widespread habitat fragmentation and the further degradation of many natural communities and at-risk species populations.

This report looks at 29 at-risk species identified by the biologists, their status and the threat posed if Highway 413 is built


How the Study for this report was done:

The biologists, Karl Heide and Dr Ryan Norris, of the University of Guelph, compiled information on the habitat requirements and threats associated with species at risk known to occur in Southern Ontario. They then used data from the Government of Ontario’s Natural Heritage Information Centre (NHIC) to map sightings of these species in the proximity of  the proposed route of Highway 413.

To confirm whether the sightings were accurate and current within the area of Highway 413, the scientists also analyzed data from the past five years from eBird, Inaturalist, the Ontario Breeding Bird Atlas, the Ontario Butterfly Atlas, the Ontario Reptile and Amphibian Atlas, the Ontario Ministry of Natural Resources and Forestry, and recent reports from the Committee on the Status of Endangered Wildlife in Canada (COSEWIC).

If built, Highway 413 would destroy species habitat including a section of the Greenbelt, pollute the many rivers and streams it would cross and impact 29 federally listed species at risk


Amphibians & Reptiles
Fish, Insects & Trees


Number of hectares of species habitat that will destroyed if Highway 413 is built


Number of rivers and streams that Highway 413 would cross if built


Here are 14 threatened or endangered species that will be impacted if Highway 413 is built, including amphibians, birds, fish, insects, reptiles and trees
  • Blanding’s Turtle – In the Greater Toronto Area, Blanding’s Turtles live in a few scattered locations along the lower Humber, Credit and Don Rivers. Because water quality is important to their survival, any upstream activities that may leach contaminants, such as Highway 413 with its multiple river crossings, could hinder the long-term viability of these populations
  • Butternut – This tree’s population has been decimated by the invasive butternut canker, a fungal disease. Few living trees in eastern North America are completely disease-free, and those with disease resistance are highly important to the future of the species. Mature Butternuts are found in several woodlots and isolated locations within the area near Highway 413.  Although Butternut is listed in Ontario as endangered, it has received little protection.  
  • Eastern Meadowlark – Studies indicate that more than half of the area near Highway 413 is occupied by Eastern Meadowlarks during the breeding season. One of the key drivers of decline for the Eastern Meadowlark is loss of habitat resulting from urbanization. Highway 413 and consequent suburban sprawl would disrupt or permanently destroy large portions of this bird’s habitat. 
  • Eastern Ribbonsnake – This non-venomous semi-aquatic snake is threatened by wetland loss, pollution and road mortality. In the area near Highway 413, Eastern Ribbonsnakes have been found along the west side of the Humber River between Rutherford Rd. and Kirby Rd. The proposed connector with Highway 427 would put significant pressure on any population of this snake that lives  in this small area. 
  • Jefferson Salamander and Unisexual Ambystoma – Because the life-cycle of the Jefferson Salamander and its genetically-dependent hybrid lookalike, the Unisexual Ambystoma requires them to migrate annually between breeding ponds and forest, these salamanders are much more vulnerable to road mortality than other species of salamander. Highway 413 will affect the salamanders in at least one key area around the proposed interchange with Highways 401 and 407. Several of the ponds in this small area are known to contain these salamanders. Highway 413  will not only contribute to possible water contamination but may also cut off key routes used by the salamanders to navigate between ponds and nearby forest. 
  • Least Bittern Least Bitterns are known to breed in several places near the proposed Highway 413, including Heart Lake Conservation Area. Major threats to this bird species include loss and contamination of wetland habitat and, because they fly low to the ground, collisions with motor vehicles. Least Bitterns would also be negatively affected by the fragmentation of wetlands which Highway 413 would cause. 
  • Monarch Butterfly – One of Canada’s best-known butterflies, the Monarch butterfly has experienced steep population declines, largely due to pesticides and to the loss of its Milkweed host plants. Road casualties of Monarchs have been reported to increase with traffic volume and road width. A new freeway such as Highway 413 may act as an ecological trap by encouraging butterflies to fly low over the roadway. 
  • Rapids Clubtail – This endangered dragonfly is extremely sensitive to degradation of river conditions from pollution (erosion, runoff) and dams.. In Canada, Rapids Clubtail currently occur along just four rivers, two being the Humber and the Credit. The Humber River population is restricted to the upper west fork between roughly Rutherford Rd. and King Rd. and recent records indicate that this population is still thriving. Highway 413 would intersect this stretch of river no matter the route chosen. In a worst case scenario, Highway 413 may eliminate the entire Humber River population of Rapids Clubtail. 
  • Red-headed Woodpecker – The Ontario population of this endangered bird  is extremely fragmented, yet Highway 413 is slated to slice through a core area where it currently lives. The highway would likely destroy important breeding habitat and contribute to road mortality of the Red-headed Woodpecker in this area and other possibly occupied places nearby. Building highway 413 would have a major impact on the Red-headed Woodpecker.
  • Redside Dace – This endangered minnow is one of Canada's most endangered fish species. Primary threats to the species include pollution of streams resulting in turbidity or water temperature increases, and removal of vegetation next to streams. Highway 413 would require roughly 132 river and stream crossings, many of them small headwater streams with suitable Redside Dace habitat. Since downstream populations in these watersheds have been greatly reduced, this means that the core of the Red Dace’s occurrence in Canada may fall within areas close to Highway 413.
  • Rusty-Patched Bumble Bee – Of the native Bumble Bee species that may be present in or near Highway 413. Of these, the Rusty-patched Bumble Bee is the most at risk of imminent global extinction.  A large-scale development project such as Highway 413 may affect struggling bee populations both directly through the loss of habitat, and indirectly by contributing to climate change. Rusty-patched Bumble Bees are restricted to temperate climates and are highly sensitive to rising temperatures linked to climate change. Highway 413 will create over 17 million tonnes of climate warming greenhouse emissions by 2050 and may contribute to the loss of available habitat for this at risk Bumble Bee
  • Short-eared Owl –  This species has suffered one of the steepest declines of any bird listed by the Federal Species at Risk Act, with over 90 per cent of its Canadian population lost since 1966. Short-eared Owls are extremely uncommon in the Greater Toronto Area but they are known to occur at the east end of Highway 413 at the proposed connection with Highway 400. Disturbance in this area resulting in the loss of grassland or other open habitats could drive away any remaining individuals in this population. 
  • Wood Thrush – The Wood Thrush is a relative of the better-known American Robin. Studies suggest that roughly half of the forest fragments near the proposed route of Highway 413 are occupied by Wood Thrush. Habitat for this declining species would most likely be degraded by impacts of noise and/or increasing urbanization in the landscape facilitated by the highway.
  • Western Chorus Frog –  These frogs get their name from their throaty, drawn-out call which resonates from ephemeral wetlands in early spring, delivered by many individuals at once. Western Chorus Frog populations have been found in select localities near the edge of the proposed route of Highway 413. Any activity that alters water quality can be extremely problematic for frogs, which breathe through their skin and are highly sensitive to contaminants such as road salts. Highway 413 will still likely leach sediment and pollutants into waterways that would travel downstream into ephemeral wetlands used by Western Chorus Frogs.

What's Next For Highway 413?

In May 2021, Highway 413 was designed for a review under Canada’s Impact Assessment Act. When this report was published in October, 2022, the Impact Assessment Agency had not yet  decided whether to conduct an impact assessment nor the scope of that assessment. However, it was expected to make those decisions in the near future.

Due to the number of species at risk impacted and the breadth of environmental impacts more generally, we recommend that the Impact Assessment Agency proceed with a full federal Impact assessment – the most comprehensive assessment possible – and conduct a thorough assessment of the risks and impacts to federally listed species at risk. 

In recent years, Ontario has watered down the Endangered Species Act, removing protection for species that are endangered locally but also live elsewhere, an approach that scientists have condemned. Ontario also launched the controversial “pay to slay” fund that allows developers to destroy endangered species habitat provided they pay into a fund managed by the province. 

Given the province’s track record on endangered species, there’s a real need for federal oversight and a full federal assessment of Highway 413.

Let's take action!

ACKNOWLEDGEMENTS: Produced by ENVIRONMENTAL DEFENCE. Researched and written by Karl Heide, M.Sc, University of Guelph and Dr. Ryan Norris, Professor,  Department of Integrative Biology, University of Guelph, with contributions by Allen Braude. For a full list of contributors please download the report.

© Copyright March 2022 by ENVIRONMENTAL DEFENCE CANADA. Permission is granted to the public to reproduce or disseminate this report, in part, or in whole, free of charge, in any format or medium without requiring specific permission. Any errors or omissions are the responsibility of ENVIRONMENTAL DEFENCE CANADA.