Cave-dwelling bats are those that inhabit caverns and abandoned mines for at least part of each year. Most of these bats hibernate in caves and inhabit other locations such as trees or man-made structures in the summer.

The cave-dwelling species that are found in Quebec are the tri-coloured bat (Perimyotis subflavus), the big brown bat (Eptesicus fuscus), the little brown bat (Myotis lucifugus), the northern long-eared myotis (Myotis septentrionalis), and the eastern small-footed bat (Myotis leibii). Apart from the little brown bat that can reside in a variety of habitats, these species live in sparsely forested areas and in pastures near water sources.

More specifically, the northern long-eared myotis occupies boreal forests, while the eastern small-footed bat favours mountainous regions. With the exception of the northern long-eared myotis, all of these species can also be found in urban areas.

Both the tri-coloured bat and the eastern small-footed bat appear in the list of species designated as threatened or vulnerable by the Quebec Act Respecting Threatened or Vulnerable Species. In 2014, the little brown bat, the northern long-eared myotis, and the tri-coloured bat were assessed by the COSEWIC (Committee on the Status of Endangered Wildlife in Canada) and added to the “Endangered Species” list compiled under Canada’s Species at Risk Act.

Several factors have affected Quebec’s bat populations. The main problems are illness, loss of habitat, the use of pesticides, and human disturbance (Fenton, 2001).

In addition to contributing to biodiversity, Quebec’s bats help eliminate many pests that are harmful to agriculture and, consequently, reduce pesticide use. (Boisseau, 2014). One study demonstrated that the consumption of insects by bats could save the North American agriculture industry 3.7 billion dollars per year (Boisseau, 2014).

In 2006, a fungus from Europe called Pseudogymnoascus destructans appeared in North America. It arrived in Quebec in 2010 (MFFP, 2015). The number of cases of white-nose syndrome, which is caused by this fungus, has risen over the years. In North America, white-nose syndrome particularly affects hibernating bat species (Dumouchel, 2015). The cold-loving fungus attacks the tissues of hibernating bats in caves, causing a fungal infection.

Consequently, infected bats wake up more often during the winter, which causes them to use up their fat reserves too quickly (COSEWIC, 2013). As a result, many bats die of exhaustion before the end of the winter. Over the past few years, hundreds of cave-dwelling bat populations have been decimated by the disease. This has led to a major imbalance in the food chains of our ecosystems.

It is estimated that between 5.7 and 6.7 million bats have died from white-nose syndrome since the fungus arrived on the continent (Dumouchel, 2015). According to COSEWIC data, 94% of tri-coloured bats, 98% of little brown bats, and 99.8% of northern long-eared myotis have died from the disease (COSEWIC, 2013).