A method to control the spread of mountain pine beetles—pheromone baiting—may actually help the pest’s population increase, UBC research shows.

A study by Rebecca Tyson, an associate professor of mathematics at UBC’s Okanagan campus, used mathematical modelling to examine several mountain pine beetle management strategies used in Banff National Park. The two-year simulation, which included then PhD candidate Shaun Strohm and University of Calgary professor Mary Reid, compared four separate management strategies: no management (monitoring only), pheromone baiting, tree removal, and finally, pheromone baiting combined with tree removal.

Pine beetle and water issues

Although Tyson’s research was not focused on water issues, the findings are significant to the region’s hydrology. First, there is evidence to show that with fewer trees, some areas in the Rockies have experienced up to 30 per cent increase in groundwater infiltration. The reason? Fewer trees results in fewer roots to soak up that water. This was demonstrated through research of two watersheds in Colorado’s Rocky Mountain National Park in a study published in 2014 by researchers from Colorado’s School of Mines in Golden, Colo. in the journal Nature Climate Change.

A study conducted for the province of British Columbia demonstrate that the effects of the Mountain Pine Beetle ultimately lead to an increased amount of water reaching the forest floor due to reduced interception. This in turn causes snowpacks to increase and altering snowpacks to melt earlier, which can lead to large scale downstream flooding.

Changes in water volumes and velocities also impact the transports large and small material downstream, resulting in sedimentation, erosion, dramatic shifts in water quality, altered fish habitat, and can wreak havoc on water infrastructure.

Beetle pheromone management

“What our study found is that where the beetle population is low, the pheromone is actually attracting more beetles and thus helping the beetle population increase,” said Tyson.

“From the field work done in Banff, we know that baiting didn’t stop the beetle epidemic,” said Tyson. “Baiting may have slowed it down, but it did not stop it.”

Tyson described the mountain pine beetle as an endemic pest capable of killing entire stands of mature pine. And while the beetle has a short lifespan, climate change and warmer winters have helped the population increase during an epidemic that began in the late 1990s.

Simulation modelling such as the method Tyson used with the mountain pine beetle can be used to help predict the influence of management strategies without creating harm to the landscape.

“This information could be very useful in determining appropriate management responses to future epidemics, and possibly also to the current epidemic as it spreads across the boreal forest,” she said. “If more data is gathered on mountain pine beetle dispersal and response to forest edges, we can continue to refine our model and predictions to provide an informative approach for future management decisions.”

Tyson’s research was recently published in ScienceDirect.

UBC associate professor of math, Rebecca Tyson used computer modelling to determine pheromone baiting isn’t the best solution to control the mountain pine beetle.


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