Synchrony and travelling waves of larch bud moth? Time series analysis with changing scale

Spatio-temporal patterns of cyclic larch bud moth population densities, for instance synchrony (valley scale) and travelling waves (Alpine arc scale), have been observed at different scales and may be related to distinct causes. In this study, quantification of population data through cross-correlation analysis and spectral analysis revealed that larch bud moth population cycles at the valley scale could be considered to be in close synchrony with one another. At the Alpine arc scale the presence of travelling waves could generally be confirmed. These results have implications for the understanding of the causal mechanisms behind the observed spatio-temporal patterns, suggesting that at the valley scale synchrony depends not only on distances between subpopulations, but is also affected by environmental/habitat characteristics that vary in space. At the Alpine scale, distance between populations is of greater importance in shaping spatio-temporal patterns than at the valley scale.