Modelling the multi-scaled nature of pest outbreaks

Recent research suggests that the spread of pest outbreaks is driven by ecological processes acting at different spatial scales. In this work, we establish a network model for the analysis and management of pest outbreaks that takes into account small-scale host-pest interactions as well as landscape topology and connectivity. The model explains outbreak cycles both for geometrid moths and bark beetles, and provides insight into the relative importance and interactions between the multi-scale drivers of outbreak dynamics. Our results demonstrate that outbreak behavior is most sensitive to changes in pest pressure at the local scale, and that accounting for the spatial connectivity of habitat patches is crucial to capturing the spreading behavior through landscapes. In contrast to early warning signals based on retrospective data, our model provides predictions of future outbreak risk based on a mechanistic understanding of the system, which we apply for landscape-scale forest management.