Seasonal dispersal in non-cyclic populations of Clethrionomys glareolus and Apodemus flavicollis

Abstract

Dispersal was studied in stable (non-cyclic) populations of Clethrionomys glareolus (Schreber, 1780) and Apodemus flavicollis (Melchior, 1834) by the removal grid method. The seasonal pattern of dispersal consisted of two distinct "waves": spring -early summer and autumn dispersers. Sex ratio and percentage distribution of adult, subadult and juvenile individuals among dispersers and in the control population were found to differ. During the breeding season a higher proportion of subadult females was found among C. glareolus dispersers, and of subadult males among A. flavicollis dispersers, than on the control grid. The dispersal rate correlated well with population growth rate during the breeding season. It has been suggested that tendencies to disperse and the population growth are both governed by breeding activity, which changes during the breeding season. Charasteristics of autumn dispersers differed between the two species; in C. glareolus they were mostly very young individuals, probably ousted from the dense autumn population, whereas in A. flavicollis they accurately reflected the composition of the control population, and could be seasonal migrants to winter habitats.

Demography of woodland rodents in fragmented habitat

“…During this study males prevailed in A. f. immigrants; among C. g. immigrants the females appeared in at least similar number. Although it might be caused, in part, by intensive losses among male C. g. immigrants in the woodlots, the same was reported by Gliwicz (1988).…”

“…Dispersal rates are seasonally variable and regard also different categories of individuals (Lidicker 1975, Gliwicz 1988. According to Anderson (1989) young males are most numerous among dispersers, at least during early summer.…”

The range of olfactory familiarity between individuals in a population of bank voles

“…This finding entitles one to suggest that the changes in the sizes and locations of rodents' home ranges described by Mazurkiewicz (1971), Bujalska (1985a, b), Gliwicz (1988) and Koskela et al (1997) may also result from the large distances they cover. The introduction of an artificial source of food to the natural spatial system of a rodent -for example a dense network of live traps -may lead to a situation in which individuals having a good food base close at hand reduce the distances they travel (eg Dominas 1963, Wolton andFlowerdew 1985).…”

Infection Dynamics of the Tick-Borne Pathogen “Candidatus Neoehrlichia mikurensis” and Coinfections with Borrelia afzelii in Bank Voles in Southern Sweden

“…Animals were divided into age categories based on their weight (23), with the following cutoffs: voles weighing Ͻ15 g were considered juveniles, voles weighing between 15 and 20 g were considered subadults, and finally voles weighing Ն20 g were considered adults. To test whether the prevalence differed between months and age classes, we performed a generalized linear mixed model with binomial error, with month and age and the interaction between them as fixed factors and individuals as the random effect.…”