EN
Rodent dynamics was once equated with 3-4 year cycles but is now understood to be many-facetted. In a typology of dynamics, including stable and resource-driven populations, extensive cycles and travelling waves appear to have many features in common. They differ mainly in the spatial extent of the cycles or waves. Both types of dynamics demonstrate lag phases. Lagged dynamics may be caused by several agents but specialist and nomadic predators are particularly evaluated in this treatise. The main conclusion is that present understanding of predator effects is limited and partly contradictory. The understanding of local dynamics, on a km -scale, might be facilitated by considering most rodent populations as partially subdivided with patches, on a hectare-scale, differing in quality and release of dispersers; an overflow to suboptimal patches (a 'mass effect') may emerge at fairly unlimited immigration. Dynamics may vary along several gradients, and spatially and temporally limited studies may only catch fragments of extensive population changes. Detailed local studies have to be complemented with extensive monitoring of dynamics.