From pattern to process? Dual travelling waves, with contrasting
propagation speeds, best describe a self-organised spatio-temporal
pattern in population growth of a cyclic rodent
Abstract
The dynamics of cyclic populations distributed in space result from the
relative strength of synchronising influences and the limited dispersal
of destabilising factors (activators and inhibitors), known to cause
multi-annual population cycles. However, while each of these have been
well studied in isolation, there is limited empirical evidence about how
the processes of synchronisation and activation-inhibition act together,
largely owing to the scarcity of datasets with sufficient spatial and
temporal scale. We assessed a variety of models that could be underlying
the spatio-temporal pattern, designed to capture both theoretical and
empirical understandings of travelling waves using large-scale
(> 35,000 km2), multi-year (2011-2017) field monitoring
data on abundances of common vole (Microtus arvalis), a cyclic
agricultural rodent pest. We found most support for a pattern formed
from the summation of two radial travelling waves with contrasting
speeds that together describe population growth rates across the region.