Bats

ALTO HSR · Flora & Fauna · Bats at Risk

Four Endangered Bat Species. One Cave. One Rail Corridor.

The Alto HSR southern route passes through the Moira Karst — a solution cave system in Hastings County that is the confirmed hibernaculum for four Endangered bat species, including what was historically the largest population of Little Brown Myotis in Southern Ontario. Federal law automatically prohibits harming them.

Reviewed by Kurt Hennige March 2026

Tri-colored bat (Perimyotis subflavus) — one of four Endangered bat species confirmed at the Moira Karst hibernaculum
Tri-colored Bat (Perimyotis subflavus) — Endangered under SARA & Ontario ESA Photo: Rachel Harper
Alto has not published a species at risk inventory for either corridor. The public consultation deadline is April 24, 2026. Every written submission naming the Moira Karst and these four species becomes part of the formal record that Alto must respond to. Submit your comments
What Is at Stake
Populations already in collapse — facing a new threat

White-nose Syndrome, caused by a fungal pathogen introduced from Europe, has devastated Ontario’s cave-hibernating bats since it was first detected here in 2010. Population declines at infected hibernacula in eastern Ontario have ranged from 85 to 99%. The Moira Karst cave was among the first sites confirmed to carry the fungus — and it has been monitored ever since as a critical refugium for four species.

These are not species at moderate risk. They are species whose populations have already largely collapsed, which survive in reduced numbers at a handful of irreplaceable sites. Adding a new major threat — construction vibration, habitat fragmentation, hydrological disruption, and operational noise from a 300 km/h rail line — to populations at this level of fragility is not a planning inconvenience. It is a potential extinction event.

Confirmed species
4 Endangered Species
All confirmed at the Moira Karst hibernaculum, all listed on SARA Schedule 1.
Population decline since 2010
85–99%
In Ontario cave hibernacula since White-nose Syndrome arrived.
Known hibernacula in Ontario
~10
For Eastern Small-footed Myotis — one of the rarest bats in North America.
CAD mitigation cost precedent
$175M+
What one bat structure cost on the UK’s HS2 project — for a single species at one location.
Why the Moira Karst is irreplaceable. A hibernaculum is not just a shelter — it is a precise microclimate. Bats return to the same caves because those caves maintain the exact temperature and humidity their bodies require to survive a five- to six-month winter on stored fat alone. They do not simply relocate if disturbed. Suitable alternatives in Ontario are limited to karst areas, and the Moira Karst is one of a very small number of such systems in Hastings County. Before White-nose Syndrome, this cave supported what was reportedly the largest population of Little Brown Myotis in all of Southern Ontario.
The Four Confirmed Species
Every species using this cave is Endangered under federal and provincial law

All four bat species confirmed at the Moira Karst hibernaculum are listed as Endangered on Schedule 1 of Canada’s Species at Risk Act (SARA) and on Ontario’s Species at Risk in Ontario list. This status is not precautionary — it reflects documented, catastrophic population losses. Federal law prohibits killing, harming, or harassing any individual of these species, or destroying the cave they use as a residence, without a permit. That permit cannot be granted if the project would jeopardize their survival or recovery.

⚠ Endangered — Federal & Provincial

Little Brown Myotis

Myotis lucifugus

Once the most abundant bat in Canada. The Moira Karst cave historically supported the largest colony in Southern Ontario. White-nose Syndrome has caused over 90% average decline in eastern Ontario hibernacula. Each forced arousal from torpor costs the equivalent of 68 days of stored fat — disturbance is directly lethal.

⚠ Endangered — Federal & Provincial

Northern Myotis

Myotis septentrionalis

A forest-dependent species that forages along interior edges and in gaps in mature woodland. About 40% of the global population lives in Canada. Confirmed 94% decline in known hibernating populations in eastern Canada and the northeastern United States.

⚠ Endangered — Federal & Provincial

Eastern Small-footed Myotis

Myotis leibii

The smallest bat in eastern North America — weighing about as much as a nickel. One of the rarest bats in Canada, with only approximately ten known hibernacula in all of Ontario, all in karst areas. Returns to the same site year after year.

⚠ Endangered — Federal & Provincial

Tri-colored Bat

Perimyotis subflavus

Canada holds an estimated 10% of the global population, found only in Ontario, Québec, New Brunswick, and Nova Scotia. Loses up to 30% of body mass during hibernation — leaving no margin for additional energy expenditure from disturbance.

The Moira Karst
A solution cave system formed over millions of years — not replaceable

The Moira Karst is a limestone karst formation in Hastings County, eastern Ontario, formed through the slow dissolution of Paleozoic carbonate bedrock over geological time. The system includes the Moira Cave — one of the largest solution cave systems in eastern Ontario, with passages extending beyond 11 kilometres. The cave system has been documented since at least the 1960s and was among the first sites in Ontario confirmed to carry White-nose Syndrome when the disease arrived in 2010.

What makes a karst cave a hibernaculum

Hibernating bats require very specific conditions: temperatures of 2–10°C, humidity above 80%, and a stable microclimate through a five- to six-month winter. These conditions occur naturally only in deep cave systems — and in Ontario, almost exclusively in karst limestone terrain. Bats using a hibernaculum demonstrate strong site fidelity, returning to the same cave year after year over decades. This is why the loss or degradation of even one hibernaculum is a significant conservation event. There is no bat box, artificial mine, or engineered structure that can replicate what a natural karst cave provides.

Why karst geology amplifies the risk

Karst limestone transmits ground-borne vibration with particular efficiency through its network of solution channels, fractures, and voids. Vibration generated by construction activity — blasting, pile-driving, vibratory compaction, heavy earthmoving — travels along these pathways and can reach cave systems at significant distances from the surface source. For hibernating bats, each vibration-induced arousal from torpor consumes fat reserves equivalent to weeks of undisturbed sleep. At a population already depleted by 85–99%, there is no energetic margin.

Impact Pathways
High-speed rail affects bats in six distinct and compounding ways

The impacts of high-speed rail on cave-hibernating bats are not limited to direct habitat clearance. Research from the UK, Europe, and North America documents multiple independent pathways — each capable of causing significant harm, and all of which would be active simultaneously during an HSR project.

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Ground-borne vibration reaching the hibernaculum

Construction blasting, pile-driving, and earthmoving generate vibration that propagates through bedrock. In karst limestone, this transmission is especially efficient. Each forced arousal from torpor costs a Little Brown Myotis the fat equivalent of 68 days of undisturbed hibernation. For WNS-affected bats already depleting fat reserves months early, additional arousal pressure can be directly lethal.

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Hydrological disruption of cave microclimate

The temperature and humidity inside a karst cave are controlled by surface water infiltration patterns. Rail construction involving drainage modification, culverting, earthworks, and de-icing chemical application can alter these patterns — shifting the thermal regime and humidity of the connected cave system, potentially rendering the hibernaculum unsuitable.

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Habitat loss and foraging fragmentation

Bats travel substantial distances between their hibernaculum and summer foraging and maternity habitats. A high-speed rail corridor severing forest edges, wetlands, and waterway corridors disrupts these movements. Research has documented that total bat activity increases more than threefold between 0 and 1,600 m from a major transport corridor — demonstrating how extensively infrastructure displacement extends beyond the physical right-of-way.

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Artificial light at night suppressing foraging

Myotis species are among the bat species most sensitive to artificial light. Construction lighting, station lighting, and infrastructure lighting introduced into previously dark landscapes disrupts foraging behaviour, blocks access to roosting sites along illuminated corridors, and forces bats onto less productive routes.

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Train-pass disturbance suppressing foraging during operation

A peer-reviewed 2021 study (Mathews & Jerem, University of Sussex, Scientific Reports) found that bat activity fell 30–50% each time a train passed, and required at least two minutes to recover. Alto’s planning documents indicate 20 to 30 trains per day in each direction. High-speed trains at 300 km/h generate considerably greater broadband noise and vibration per pass than the conventional trains in the study. For populations already depleted 85–99%, the energetic cost of repeated forced evasive responses leaves no margin for error.

Permanent barrier effect isolating the hibernaculum

High-speed rail infrastructure — fencing, noise barriers, catenary, grade separation — creates a perceptually and physically impermeable linear barrier. If this barrier severs the movement corridor between the Moira Karst and productive summer range, the hibernaculum population becomes isolated from the foraging and maternity habitats it depends on seasonally. Given the low reproductive rates of all four species (typically one pup per female per year), isolated populations face a direct extinction risk.

“Taking evasive action every time a train passes may be energetically expensive, and reduce feeding opportunities, potentially disadvantaging bats using rail-side habitats.”

— Dr. Paul Jerem, co-author, “Passing rail traffic reduces bat activity,” Scientific Reports, 2021
The International Precedent
HS2 built a £100 million bat structure. A government review found no cheaper option.
Sheephouse Wood, Buckinghamshire — UK HS2.
£100M+
CAD ~$175 million · 2024 prices · 900 m structure · one species

HS2’s Sheephouse Wood Bat Mitigation Structure is a 900-metre-long, up to 10-metre-high steel mesh arch enclosing the railway as it passes through habitat used by Bechstein’s bat — a species with fewer than ten breeding colonies in all of England. The structure must span four tracks, withstand concurrent train derailments, passively ventilate, and is designed for a 120-year service life.

In 2021, the UK government convened a review by the Department for Transport, DEFRA, and Natural England to determine whether any cheaper alternative existed. It did not. The legal firm Herbert Smith Freehills summarised the outcome: “If HS2 couldn’t have shown that the Bechstein bat colony would stay in favourable conservation status, they simply could not have built the line through Sheephouse Wood.”

This is the precedent that applies to Alto HSR near the Moira Karst — but with four Endangered species instead of one, all populations already decimated, and a karst substrate that makes vibration management substantially more complex.

What this means for Alto’s budget
Alto’s publicly stated capital cost estimate is CAD $60–90 billion (Class 5, 2024 dollars). There is no public indication that bat mitigation costs for the Moira Karst section have been incorporated at a scale commensurate with HS2 precedent. Based on international evidence, a conservative scenario for the Moira Karst alone — four Endangered species, karst substrate, vibration complexity — would place bat-specific mitigation costs in the range of CAD $100–200 million. This is a material budget risk that has not been publicly disclosed.
The alternative test
Under SARA s.73(3)(a), any permit requires demonstrating that all reasonable alternatives that would reduce the impact on the species have been considered. A northern corridor alignment that avoids the Moira Karst system entirely is a reasonable alternative. Alto must demonstrate why that alternative was rejected — and that analysis has not been published.
Federal Law
SARA’s prohibitions are automatic. They cannot be overridden by fast-tracking legislation.

Canada’s Species at Risk Act creates binding legal obligations the moment a species is listed on Schedule 1. All four Moira Karst bat species have been listed as Endangered since 2012–2014. These obligations apply to Alto HSR as a federal Crown corporation project.

Ontario’s Bill 5 makes SARA more important, not less. Ontario’s Bill 5 (in force June 2025) has significantly narrowed the provincial Endangered Species Act’s habitat definition, restricting protection to a species’ immediate dwelling place. The combined effect is that SARA is now the primary — and increasingly sole — substantive legal protection for these bat species, particularly regarding broader foraging and movement habitat. This raises the live legal question of whether Ontario’s amended provincial law still “effectively protects” the species under SARA s.34, potentially extending SARA prohibitions automatically to provincial lands along the corridor.
Key Findings
What Alto must address — and hasn’t

The Moira Karst hibernaculum contains four SARA-listed Endangered species, all at active risk of extirpation. Populations have declined 85–99% in eastern Ontario since 2010.

Rail construction and operation present six distinct, compounding pathways of impact: construction vibration, hydrological disruption, habitat fragmentation, light pollution, operational train disturbance, and barrier effects.

International precedent — HS2’s £100M+ Sheephouse Wood structure — confirms that bat mitigation near HSR is non-negotiable and fiscally material. A government review found no cheaper option.

SARA’s automatic prohibitions apply to all four species. No exemption exists for infrastructure projects. Bill C-15’s fast-tracking powers do not override them.

The SARA permit test requires demonstrating that the project will not jeopardize survival or recovery. For populations at near-collapse, this may be impossible to satisfy — making route avoidance the only legal pathway.

Alto’s $60–90B budget does not visibly incorporate bat mitigation costs at a scale consistent with HS2 precedent. The Moira Karst section alone could require CAD $100–200M.

What must happen before route selection is finalized:
  • Commission independent multi-season bat surveys at the Moira Karst cave system, covering all four confirmed species
  • Commission independent geotechnical vibration pathway assessment specific to karst terrain
  • Conduct and publish a formal route alternatives analysis demonstrating why alternatives that avoid the Moira Karst were or were not considered
  • Engage ECCC Canadian Wildlife Service and Ontario MNRF in pre-consultation — before route selection, not after
  • Disclose bat mitigation as a material budget risk in all public consultations, with a cost scenario based on HS2 precedent
  • Require that the Environmental Impact Statement address bat species at risk as a distinct, site-specific topic