Characterizing the speed and severity of mountain pine beetle spread under climate change with a mechanistic model

Abstract

In the last few decades, mountain pine beetle (MPB) have spread into Alberta, partially facilitated by climate change and warmer winters. Future effects of climate change on pine beetle spread are uncertain as warming is likely to affect both forest growth and beetle development. We here present a mechanistic model of pine beetle dynamics and characterize simulated outbreaks under climate change. This model includes key aspects of pine beetle biology, and we determine plausible ranges for each model parameter from available data. We then consider how forest growth, beetle brood size, and host resistance are likely to change in Alberta by the end of the century, and how this will relate to changes in model parameters. We simulate beetle outbreaks and quantify how the projected change in the distribution of the parameters will affect the period, speed, and severity of pine beetle spread. We find that simulated beetle outbreaks move more quickly than historically and are more severe.