Holly Hennin set out two years ago to determine if converting cropland to pasture increases species diversity in Saskatchewan.
The master’s student in biology at the University of Regina didn’t find evidence that such a conversion helps burrowing owls or the number of ground squirrels and mice in the province.
“In small mammals, permanent cover didn’t seem to have much of an effect, which was a strange result to me,” said Hennin. “I kind of expected that with higher diversity of vegetation, there would be more diverse species.”
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Hennin’s thesis looked at the benefits of programs that turn cropland into pasture, such as Environment Canada’s Habitat Stewardship Program for Species at Risk.
The federal initiative provides financial help to farmers who cultivate their cropland and seed grass on the acres for pasture.
The burrowing owl is of special interest, said Andrea Kotylak, a habitat stewardship co-ordinator with Nature Saskatchewan, which implements the program in the province.
“If we converted some cropland to pasture, maybe that could help the decline of the (burrowing owl) population,” Kotylak.
Since 2000, Nature Saskatchewan has helped convert 121 sites from cropland to pasture, representing 15,200 acres across the province.
Hennin looked at whether in-creased pasture land increases the number of burrowing owls.
There are only 200 to 400 pairs of the owls in the province and finding them is a hit or miss proposition, Kotylak said.
Hennin expanded her study to find mice, gophers and grasshoppers, species that are food for burrowing owls.
“There are so many other species that could potentially benefit from these permanent cover restoration sites,” Hennin said. “So the study kind of expanded.”
In 2008 and 2009, Hennin visited 33 of the restoration sites across Saskatchewan, where she used mousetraps to count the number of small mammals and sweep nets to measure the number of grasshoppers.
At each location, she duplicated the study on a nearby piece of cropland and chunk of native grassland to gather information on small mammals and grasshoppers.
After looking at all the locations over two years, from Val Marie to Estevan and up to Last Mountain Lake, Hennin only found one pair of burrowing owls.
“(But) we actually found the pair on one of the permanent cover sites, which is excellent news for the habitat stewardship program,” she said.
Hennin recorded more grasshoppers on the restored permanent cover sites, compared to nearby cropland. But she didn’t find more mice, gophers and other small mammals on the permanent cover sites.
She did find more small mammals on the native prairie sites. Perhaps because the longer grass on the native prairie provided the needed protection from predators, such as hawks.
Not detecting a substantial number of burrowing owls or finding a significant increase in prey species doesn’t mean the crop conversion program is a failure, Kotylak said.
The program has only been going for a decade and some of the sites have been in pasture for just a few years.
Burrowing owls would likely benefit if cropland that surrounds a piece of native prairie is switched to pasture.
“A lot of parcels of native prairie that are out there are so small,” she said.
“But if we’re converting the cropland around it to pasture, it just makes a bigger parcel for them to live and hide on.”
Hennin plans to submit her research to the Journal of Biological Conservation.
