North American Bat Monitoring Program: Alberta 2019 Final Report
Executive Summary for the Final Report
Nine species of bat occur in Alberta with at least five species considered to be susceptible to population decline due to either disease (white-nose syndrome; WNS) or fatalities at wind energy facilities. Since 2015 Alberta has been a part of the North American Bat Monitoring Program (NABat) to gather data on current provincial bat distributions and relative abundances, predominantly through passive and mobile acoustic surveys. In 2019, 14 NABat grid cells were acoustically surveyed; between one and four detectors surveyed each grid cell with a total of 310 nights of passive acoustic surveys and 6 nights of mobile acoustic surveys. For the passive surveys, sites were surveyed a mean of 9.4 nights (range of 3-28 nights). Each mobile survey consisted of two surveys per transect. Unfortunately, the 2019 survey period coincided with sub-optimal weather for bat monitoring. Some passive acoustic surveys experienced recording issues and/or extremely low detections and some mobile acoustic surveys were never completed due to the poor weather.
There were a total of 13,868 bat call sequences recorded during the passive surveys, with just under half (6669 or 48%) identified to species/species group. Similar to previous years, bat call sequences were most often identified as Myotis lucifugus, Myotis 40k, or L. cinereus (2299 or 35%, 1450 or 22%, and 1234 or 19% respectively). The mobile surveys recorded 168 bat call sequences, with two-thirds (121 or 65%) identified to species / species group, predominantly attributed to the Myotis 40k species group. The majority of the NABat passive acoustic surveys occurred prior to 10 July 2019 and mean nightly bat activity was highly variable, both in time and space, with some species having discrepancies in mean nightly activity between detectors within the same grid cell. This variability underscores the importance of sampling for multiple nights at more than one quadrant per grid cell during each survey to increase the likelihood that all bat species present are observed.
As in previous years, these findings have serious implications for the conservation and maintenance of Alberta’s bat populations with the increasing and emerging threats of WNS and wind energy development. In Alberta, NABat surveys have been conducted in five of the six provincial Natural Regions, with the majority in the Boreal, consistent surveys in the Foothills, Grasslands and Rocky Mountain, and limited surveys in the Canadian Shield. Future surveys should aim to fill gaps in the provincial distribution of surveys, particularly in the Parklands and Canadian Shield Natural Regions. As well, surveys should be concentrated in areas where populations are expected to decline, from either WNS (potential threat from south-west as WNS expands out from Washington State) or wind fatalities (wind belt of southern Alberta). Acoustic surveys have occurred between 1-5 times at each grid cell; there now is sufficient data to evaluate the efficacy of the NABat acoustic monitoring approach within Alberta and to investigate provincial trends for potentially at-risk species, such as L. cinereus and M. lucifugus. In addition, continued searching for winter hibernaculum and maternity colonies of species susceptible to WNS should be a priority.