Evidence of spatial synchrony in the spread of an invasive forest pest

Because population growth is a key component of range expansion, spatial synchrony in population growth along a species’ range edge may lead to spatial synchrony in range expansion. However, demographic stochasticity in low-density range-edge populations and stochastic long-distance dispersal may disrupt the synchronization of range expansion. Here, we investigate whether rates of spread by an invasive species, the spongy moth, exhibit spatial synchrony. We also evaluate if climatic oscillations at multi-annual timescales arising from teleconnections synchronize spread at similar timescales. We applied extensions of wavelet analysis to spatiotemporal data on climate variables and range-edge abundances during 1990-2020. Synchrony in spread occurred throughout the entire study area, and in the northernmost and southernmost ecoregions, synchrony in spread was explained by multi-annual climate oscillations linked to teleconnection patterns. We demonstrate spatial synchrony in invasive spread and find an opportunity to predict the timing of pulses of invasive spread at regional scales.