Changes over time in the spatiotemporal dynamics of field voles (Microtus agrestis L.)

Abstract
Close relationships between the dynamics in space and time are predicted when models of populations that are governed locally by non-linear interactions are embedded in spatial landscapes by dispersal. Evidence of such closely linked spatial and temporal dynamics is however lacking. We demonstrate coinciding changes over time in the spatial and temporal dynamics of an herbivorous small rodent by analyzing time-series of seasonal estimates of population densities, obtained at 21 locations on clear cuts within a coniferous forest in Britain from 1984 to 2004. Marked changes had taken place in the amplitude, periodicity and synchrony of population density fluctuations, and density-dependent feedback on population growth rates. Evidence for the presence of a unidirectional travelling wave in rodent abundance was strong near the beginning of the study period, but had disappeared near the end. The observed coincident changes provide strong evidence for the existence of close relationships between the dynamics in space and time, and the existence of spatiotemporal self-organization, in these rodent populations. Changes in the winter climate are likely to have contributed to changes in spatiotemporal dynamics, which were markedly season-specific. Similar long-term changes in the dynamics of rodents and the climate as reported from Fennoscandia indicate the involvement of large-scale climatic variables. This study illustrates how spatiotemporal patterns in population dynamics can be uncovered in more detail when dynamical non-stationarity is acknowledged and flexible statistical tools are used.
Year
2006
Category
Refereed journal
Output Tags
SG 2006-2011 P3 Environment - Miscellaneous