Peter Shokeir | [email protected]
Mountain pine beetle populations are mixing more than originally speculated, according to a recent study by University of Alberta biologists.
The study confirmed that most beetles in Hinton are coming from Jasper, while most beetles moving across the north originated from the population that entered through Grande Prairie.
But researchers also discovered Jasper beetles as far east as Slave Lake, whereas Grande Prairie beetles have been found in Hinton.
“A lot of blame was being put on Jasper for the beetles that came into Hinton,” said Victor Shegelski, the study’s lead author.
“The interesting thing that we found was there were actually several beetles in that Hinton region that came from the northern Grande Prairie population, so that tells us that Hinton essentially – and unfortunately – would have gotten hit regardless.”
The mountain pine beetle is a tree-killing bark beetle that has historically been confined to British Columbia and southwestern Alberta.
During the 2000s, however, the population exploded and expanded into northwestern Alberta due partly to climate change and fire suppression.
Hinton has been hit hard by the infestation, and the pest has also been found along the Saskatchewan border and has established populations in Lac La Biche.
“Up until we looked at it, there were a lot of assumptions on where these populations were coming from,” Shegelski said.
“I mean, it was kind of assumed that the populations that came through Jasper were the ones that hit Hinton and then were moving east, and then it was assumed that the ones in the north were the ones that were just spreading straight across into areas like Lac Lac Biche.”
Researchers were able to track the spread, as the three populations of the mountain pine beetle in Alberta are all genetically distinct.
A southern population ranges as far north as Banff and Canmore, and a more recently established northern one extends eastwards past Grande Prairie.
There is also an intermediate population – a genetic mix of northern and southern – that entered Alberta through Jasper.
Sheglski and his team collected a total of 306 specimens at 44 different sites from nine locations between 2014 and 2018.
“Then we sequenced their DNA so that we could then compare where they were caught to what their genetic population looks,” Sheglski said.
The study revealed that there is more genetic mixing going on between the three populations than first speculated.
In addition, the spread between sites in northern locations – such as Grande Prairie, Whitecourt and Slave Lake – is moving so fast that there is no time for them to become genetically distinct from one another.
Sheglski noted how the study confirmed some of the ideas behind the current management strategy in Alberta, such as how the province splits resources between mitigating the damage in highly infested interior forests and stopping the spread at leading edges, rather than just focusing on the leading edges.
“Because we know how far they spread and how quickly they spread, by reducing the number of beetles at these interior forests, you’re also reducing the number of beetles that are actually able to spread to the leading edge,” he said.
“So, this actually helps reduce the chances of establishment at the leading edge.”
The spread has also been slowed by the cold winters and wet summers in recent years, but Sheglski warned that the mountain pine beetle wasn’t going to be leaving Alberta any time soon.
“They’re going to be here and they do go through these cycles where they have outbreaks, so they’re probably going to have more outbreaks in the future,” he said.
“The more we focus on them now and the more we understand them, the better we’ll be able to respond to that in the future.”
Along with Shegelski, the authors include Erin Campbell, Kirsten Thompson, Caroline Whitehouse and Felix Sperling.
