Winter bat research was carried out in the East and West Kootenay regions in the Columbia Basin using bat detectors to determine population and species variety in a number of sites. Most activity was detected throughout winter at most low elevation sites. Big Brown bats, Silver-haired bats, Californian Myotis and Townsend’s big-eared bats, were the four species that acoustic detectors mainly detected. Most activity occurred in low elevations near open water including Kootenay Lake, Pend D’Oreille and Columbia River, and less activity detected in higher elevations, e.g. Retallick area. Various methods revealed high population rates in rock crevices by Yuma myotis and Little brown myotis during late fall. Future conservation of these bats includes gating of mines to prevent human activity and disturbance.
Background of Research Project
The purpose of the study is to identify bat roosts in the Columbia Basin, to determine population sizes and the variety of species that gather here over wintertime and hibernation.
Methods
A variety of methods were used to collect data; acoustics, mistnetting, radiotracking and genetic sampling techniques were conducted. Acoustic data was taken using ultrasound bat detectors and were installed in numerous locations with assumed bat activity including cliffs, areas of high mine density and areas near open water etc. RoostLoggers were also used for long-term monitoring of bat patterns and activity rates during the winter to determine seasonal patterns. RosotLoggers have a short detection distances of approximately 5-15m so detection of bat activity was limited. A total of 257 bats were mistnetted in the East and West Kootenays from September 2012 to April 2013, collecting data from 9 species. Radiotracking data collection was primarily used in the Creston area in late October until mid December 2012, bats were captured and fitted with transmitters to determine how often they left the roost and how far they travelled. Radiotracking was also used to determine patterns of bats travelling to the same location and to identify large roosts. Genetic information was obtained by simple inspection of bat species in a variety of roosts with minimal disturbance as possible. Bats producing 35-40kHz and 45-50kHz were captured. Two main bat hibernacula in mines were identified in winter 2012-2013 and previous data confirmed feeding in mines in winter 2011-2012. In addition, Reeves Macdonald mine (REMAC) contained several Myotis species in September, including long-legged (Myotis volans), long-eared (M. Evotis) and Yuma myotis (M. Yumanensis).
Results
Findings from the REMAC mine proved significant, with a total of 8 of 9 known bat species observed at this location between September to December 2012. Many bats were banded and recaptures were low. The four bat species (Big Brown, Townsend’s Big-eared, Californian Myotis and Silverhaired) were confirmed to be hibernating in this mine during winter months, the largest range of bat species ever recorded hibernating at a single area in BC. 15 bats were radiotracked over the 2 month period and several new roosts were located in the Columbia Basin. 4 were found in rock crevices and 2 in building roosts but others were unable to be pinpointed to a specific area. As of December 2012, one of the building roosts was still occupied, and the other one appeared to be abandoned, perhaps due to the installation of the Rh datalogger, as no bats were seen following this. No further Rh datalogger installations were planned until a better understanding of how human interaction affects bats and their roosts was gained.
Discussion
The most significant data collected was obtained through acoustic methods, determining that two species (M. Lucifugus and M. Yumanensis) reside in the Creston area until very late winter before hibernating. Banded bats were only recaptured 4 times, suggesting that the REMAC mine houses a significant population of bats in the Columbia Basin each season with greater population rates in the winter months. Furthermore, genetic data showed various species being housed in this mine during hibernation and further suggests that this area is the largest and most diverse bat roost known across the BC region. However, the population of bats in the REMAC mine declines during spring, and the population in summer was unknown as of 2013. Radiotracking data delivered results showing large roosts of bats in several locations, one of which was abandoned following human interaction and installation of the Rh datalogger. This data suggests that bats are not tolerable to disturbance during winter months.
Conservation
Efforts are being made to encourage people to be cautious around the mines and raise awareness of the impacts on bats if disturbed. Also people are encouraged to take precautions to prevent bringing of spores of fungus (Geomyces destructans) into the habitat that causes White Nose Syndrome. Furthermore, discussions continue with timber companies to decrease the rate of logging during winter months near Queen Victoria mine and bat hibernation areas. Queen Victoria mine was previously the most populous bat hibernation spot before the discovery of REMAC mine. BC Timber Sales (BCTS) agreed to reduce logging around the Queen Victoria mine, preventing potential structural damage that would be caused by cutblocks through the mine. The sheer size of REMAC mine is so large that it is almost impossible to completely gate off to the public. However, most areas are inaccessible to human use anyway; therefore, gating is unnecessary in some areas. FWCP, Nature Conservancy Canada and Sustainable Forestry Initiative were progressing towards preventing further human activity by gating the mine, BCTS also supported this by putting their logo on the gating at the mine entrance.
Future Direction
Prospected winter work aimed to analyze acoustic data through 2013 and further identify bat patterns in winter to determine where surveys should continue in the Kootenay regions. Further analysis could help better prepare for White Nose Syndrome, in relation to habitat features such as open water, mines, rock crevices etc., and also patterns related to elevation and ecotype zones. Deeper research into REMAC mine in the Pend D’Oreille is required to determine year-round use of this mine, variety of species through the year and also population rates during hibernation in winter months. Further investigation into the Queen Victoria mine and tree use could prove useful in predicting preferable areas of bat habitats during hibernation. Radiotracking from previous years showed substantial use of trees through the winter, with bats hibernating in trees within 400-500m of the mine. Broader analysis of this could determine if patterns holds true annually in wintertime. This could also contribute towards prediction of other mines that hold similar structural and surrounding features that my be preferable to bats during winter and hibernation. Comparison between REMAC and Queen Victoria mine could identify habitat preferneces, whether bats depend on trees mid-winter as well as mines and rock crevices, specifically the silver-haired bat found at both sites. Continued protection of REMAC mine could be worthwhile, the reopening or closing of this mine due to human safety impacts would also impact bat populations. However, due to low human disturbance and inaccessibility could be more worthwhile focusing efforts on a more threatened site. Bats in the Creston area show high activity rates during late fall. Investigation could be conducted into the area using radiotracking to determine how significant elevation and drainage is during hibernation. Focusing specifically on M. Lucifugus and M. Yumanensis, these species were not detected during mid-winter and could potentially be hibernating in building roosts elsewhere in BC during winter.
Bats in:
- Evergreen Stewardship Plan for Lillooet Sub Region
- Evergreen Stewardship Plan for South Chilcotin Sub Region
- Source Cori Lausen. 2013. Identifying and securing hibernation habitat for bats in the Columbia Basin in response to risk of White Nose Syndrome Year 2 End of Season Report. Prepared by Wildlife Conservation Society Canada. Available at : https://static1.squarespace.com/static/529bc87be4b0d8d4512dadc4/t/52d6d253e4b065c7c0eae686/1389810259844/2013+FWCP+Yr2+Bat+Report.pdf [Accessed 03/2021].