Jennifer Sauri Ramirez
ProjectEffect of climate change and host tree phenology on the spatial extent of spruce budworm outbreaks: an agent-based approach
The impact of climate change on the phenological synchrony between outbreaking insects and their host trees have the potential to alter spatial population dynamics and cause larger outbreaks. The spruce budworm (Choristoneura fumiferana) is the most significant forest insect disturbance in North America’s forests. Currently, the spruce budworm feed primarily on the balsam fir (Abies balsamea) due to better synchrony between the fir budburst and the budworm feeding phase, the black spruce (Picea mariana) being a secondary host. However, it has been suggested that due to climate change, the phenological synchrony between spruce budworm and its host trees might change, increasing the susceptibility of host, particularly the black spruce, further north in the boreal forest. However, the dynamics of these interactions have not yet been fully explored. Using a spatial agent-based model, we investigate how a temperature increases of 2°C and 4°C might affect phenological synchrony between the spruce budworm and its host species, and how these changes might affect the spatial extent of future outbreaks over a 20 years span. Our simulation results indicate that host trees-insect phenological synchrony is strongly affected by temperature changes, but in a non-linear way. An increase of 2°C was found to reduce outbreak extent due to poor larval survival, while an increase of 4°C resulted in higher insect survival and larger outbreaks. Our model can help to forecast future forest dynamics and facilitate the development of better management strategies to reduce the effect of outbreaks on forest landscapes.