Finding Suitable Overwintering Habitat for the
Little Brown Bat (Myotis lucifugus) in the Elk Valley

Laura Stewart
IEP – 271
April 10 2019

Importance
The little brown bat or little brown myotis (Myotis lucifugus) is a species of myotis that
is widespread across most of North America and is federally endangered and yellow
listed in BC.
In winter months, the little brown bat leaves summer roost sites to migrate to
overwintering hibernacula where it will remain during the colder months. In British
Columbia, little is known about these winter locations. What is known however, is that
the little brown bat hibernates in caves, abandoned mines and similar sites with
relatively stable temperatures. Additional parameters have also been identified by
the client.
To arrest or reverse the decline of the species, critical habitat must be identified.
Critical habitat as defined by the Species at Risk Act (SARA) is habitat that is
necessary for the survival or recovery of the species. For this species, critical habitat
can include overwintering, summering and swarming habitat. When critical habitat is
identified either in a recovery strategy or an action plan, SARA requires that critical
habitat then be protected.
This project aims to identify potential overwintering habitat in the Elk Valley of British
Columbia and Alberta.

Methodology
Data acquired online and derived from a DEM was used in an overlay analysis to
generate areas of high habitat suitability. A 10km buffer was added to the study area
so that suitable areas slightly outside the boundary may be identified as well. Areas
were ranked in order of overlapping parameters; highest ranking being areas
containing all parameters followed by those with descending matches. Because the
area where all parameters overlapped is quite small, a new point featureclass,
displayed as a star, was added in order to more effectively display these areas.
Habitat parameters provided by client : slope of 50 – 90 degrees, aspect between 135
– 215, elevation of valley bottom to 1350m, 2km distance to water, and abandoned
mine sites.

Data Acquired from Online Resources
•Digital elevation models (DEM)
•Rivers and water bodies
•Abandoned mine sites in British Columbia and Alberta

Data Derived from DEM

Results and Discussion

•Slope (50-90 degrees)
•Aspect (135-215)
•Elevation (Valley bottom to 1350m)

There is 74.4 km2 of ideal overwintering habitat in the study area including the 10km buffer, these locations are represented with green stars. There is 698.8
km2 of suitable habitat in study area including the 10km buffer, these locations are represented by pink stars. Ideal habitat differs from suitable in that ideal
habitat are areas that contain all habitat parameters and suitable habitat are areas that contain all parameters minus historic mine sites.
(Right)

Data Sources

Tools Used
•Merge
•Clip
•Buffer
•Rasterize

•Raster Calculator
•Reclassify
•Raster Clip

•Altais.com
•Alberta Energy Regulator
•CanVec.com
•Ministry of Energy, Mines and
Petroleum Resources

Alternatively, there are 699 km2 within the 10km boundary that contain 3 of either slope, elevation, aspect or distance to waterbodies and 416 km2 within the
boundary. Areas where 2 of the parameters overlap comprise 5,067 km2 within the 10 km buffer and 3,326 km2 within the boundary.
(Left)
The identified areas can now be surveyed for winter bat activity, beginning with ideal habitat locations. If overwintering bats are detected, steps can be taken
to gain federal protection of the area(s).