O.N. Bjørnstad, S. Champely, N.C. Stenseth and T. Saitoh: Cyclicity and stability of grey-sided voles, Clethrionomys rufocanus, of Hokkaido - spectral and principal components analyses

Philosophical Transactions of the Royal Society of London B (1996) 351:867-875


A spatio-temporal data panel of abundances of the grey-sided vole of Hokkaido (Japan) is analysed. The data consist of annual censuses of 90 populations from 1962-1992. The region studied cover approximately 160x220km. The 90 time series of length 31 years is analysed using a combination of spectral analysis, principal components analysis and graphical methods. Through this we demonstrate that vole populations in the coastal north-western part of Hokkaido exhibit seasonal population dynamics, whereas those in the more mountainous north-eastern and central part exhibit multi-annual cycles. The multi-annual cycles have a period of 3.5-4 years. The findings are related to other studies from Hokkaido as well as studies of North European microtines.

Key words: Comparative population dynamics; Spatio-temporal pattern; Rodent abundance; Time series; Multivariate Analysis