A comprehensive bat inventory in Grasslands National Park has confirmed the presence of seven bat species and four of these species are now also known to be breeding in the park.
The first-ever inventory of bats in the park started in the summer of 2018 and the work continued in July 2019.
Sherri Clifford, manager of resource conservation at Grasslands National Park, said the information will help to guide management decisions by staff.
“It's very important to have the baseline information so that you can direct your management decisions appropriately,” she mentioned. “When you have 30 species at risk, like we do here, you have to choose very carefully, and this was a big gap in our understanding.”
There are at least eight bat species in Saskatchewan and seven can potentially be found in southern Saskatchewan. This inventory has confirmed the presence of all seven these species in the park.
Few comprehensive bat surveys have been completed in southern Saskatchewan and this inventory will help to fill the gaps of information.
“It's important to continue this work into the future, because of course we were only able to inventory key areas where we were pretty sure bats might be,” she said. “There are many other buildings and many other structures in the park. We still have to get to those, but at least we've dipped our toe into the water and we're getting started on this.”
They focused the inventory on areas in the park where bats might be found. There are various structures in the park that might attract bats, such as former farm yards with old structures, and they also found them under bridges.
Bats on the prairie are associated with riparian habitats, which they will use for roosting and foraging. These areas also give them access to drinking water and it provides them with migratory corridors.
There is suitable habitat in the park along two riparian systems, the Frenchman River and Rock Creek. Deep erosion cavities in the park might provide suitable sites for roosting and hibernation.
“We don't know yet if there's any overwintering activity happening,” she said. “Bats are incapable of overwintering in any place that doesn't have any heat. So we know they wouldn't be hibernating in any of those old buildings, but they can certainly be roosting and now we know they're also raising their young in those buildings. Another gap in our knowledge is if they are hibernating somewhere else, not in a building, but in deep rock crevices or somewhere sheltered underground or under rocks.”
Park staff worked with a contractor, who is a bat expert, to carry out the inventory. They used various methods, such as acoustic detection, building inspections, roost surveys, and exit counts, which is done when bats emerge from a roost at night. They did non-invasive genetic sampling, which is done by taking wing swabs, and they also got genetic information from guano samples collected in buildings.
Most bat species cannot be reliably identified without direct handling and it was therefore necessary to capture them with mist nets.
“It consists of a very fine net hung like a volleyball net in areas likely to be visited by bats,” she said. “The bats fly into it and become entangled. We watch it closely so the bat can be quickly removed, examined to collect the information needed, and released.”
The 2018 inventory confirmed that the Little Brown Bat, a species listed as endangered under the Species at Risk Act, is breeding in the park. This bat species has been identified as a priority for population monitoring and recovery actions within Grasslands National Park.
It has been listed as endangered due to the impact of white-nose syndrome, a disease of bats caused by an exotic invasive fungus that was introduced to North America around 2006.
White-nose syndrome is not currently known to be in Saskatchewan, but it was recently detected in Riding Mountain National Park near the Manitoba-Saskatchewan border. The bat inventory in Grasslands National Park will therefore provide important baseline data to manage and monitor the potential impact of this disease.
The other bat species confirmed to be present in the park are the Hoary Bat, Eastern Red Bat, Silver-haired Bat, Big Brown Bat, Long-eared Bat, and Western Small-footed Bat. The inventory also confirmed that the Hoary Bat, Big Brown Bat, and Long-eared Bat are breeding in the park.
The capture of five male Western Small-footed Bats was a surprise, because Grasslands National Park is near the periphery of their known range. These bats are common along the Milk River in Alberta and near the Montana-Saskatchewan border. Another highlight of the inventory was the discovery of the Little Brown Bat maternity roost in 2018.
“It's common for Little Brown Bats to have maternity roosts in old buildings,” she said. “We have a number of old farm yards scattered throughout the park and so that's where we found them.”
All seven bat species in the park are insect eaters, and they can consume up to half their body weight in insects in a single night.
“One thing that people don't realize is how important they are in terms of insect consumption,” she said. “About 70 per cent of bats only eat insects and they consume large numbers throughout their growing season. What that means to the agricultural industry is pretty important.”
Clifford added that bats are good indicators of the health of an ecosystem, because they are very sensitive to stressors that may affect other organisms.
“Bats don’t have the benefit of status that other more charismatic megafauna benefit from and so they can either go unnoticed or be misunderstood,” she said. “People can’t care about something they aren’t aware of. An important part of the work Parks Canada does is to inform the public about these species, to demonstrate that they are here, are deserving of respect, and to educate about why protecting them is important.”