# Evidence of Spatial Synchrony in the Spread of an Invasive Forest Pest

## TL;DR

The study shows that the spread of an invasive forest pest, the spongy moth, is spatially synchronized and influenced by climate patterns.

## Contribution

The study demonstrates a new form of spatial synchrony in invasive species spread linked to climate oscillations.

## Key findings

- Spatial synchrony in the spread of the spongy moth was observed across the study area.
- Multi-annual climate oscillations linked to teleconnection patterns explained synchronized spread in northernmost and southernmost ecoregions.
- The findings suggest opportunities to predict pulses of invasive spread at regional scales.

## Abstract

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 synchronisation of range expansion. Here, we investigate whether rates of spread by an invasive species, the spongy moth and exhibit spatial synchrony. We also evaluate if climatic oscillations at multi‐annual timescales arising from teleconnections synchronise 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, but only in the northernmost and southernmost ecoregions was synchrony in spread 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.

Although synchrony in population growth rates and abundance is ubiquitous across many taxa, this study demonstrates a new manifestation of this phenomenon, that of spatial synchrony in range expansion. Just as climatic drivers can produce synchrony in population growth or abundance, we show that synchronised fluctuations in seasonal climate conditions, such as those created by teleconnection patterns, can synchronise spread rates of the spongy moth, a major forest pest in North America. If prevalent, this phenomenon could prove critical to management efforts aimed at either controlling the spread of pests and disease vectors or facilitating the movement of rare species as the climate changes.