Optimal width of movement corridors for root voles: Not too narrow and not too wide

1. The characteristics of male root vole movements as a function of corridor width were tested in a 310 m long habitat corridor connecting two habitat patches. Detailed observations of movements were made by means of radiotelemetry and recording of footprints. 2. The highest connectivity, in terms of transference rate of individuals in the corridor system, was observed in the intermediate of three corridor widths tested (3 m, 1 m and 0.4 m). 3. The behavioural mechanism behind the lower connectivity of the narrowest corridor was a reluctance of voles to enter it, while linear progress in the widest corridor was hampered by a high frequency of cross-directional movements. 4. The relationship between corridor width and movement behaviour was unaffected by the simulated presence of competitors and predators. 5. Our results challenge the 'the-wider-the-better' principle of movement corridor design, and provide elements for an understanding of the behavioural mechanisms underlying the movement ecology of individuals in linear habitats.