The local patterns of distribution and resource utilization of four bat species (Myotis brandti, Eptesicus nilssoni, Plecotus auritus and Pipistrellus pipistrellus) were examined in patchy and continuous environments, using bat detectors. The effects of two different kinds of open matrix habitats (crop-fields and water) on species occurrence were compared in the patchy areas. A crop-field matrix seemed to have a greater negative influence on species occurrence than a water matrix. Presence and absence of species in the patchy areas were analysed against island area, area of some habitats, and isolation. All species were positively affected by one or more forest habitat parameters. Two species (M. brandti and P. auritus) were negatively affected by isolation, which suggests that they may be particularly vulnerable to increased forest patchiness. These species occurred mainly on large islands. Two hypotheses that might explain the habit of open area avoidance in M. brandti and P. auritus were tested: 1. Insect abundance hypothesis; 2. Foraging behaviour hypothesis. Both failed to explain why these two species avoid open habitats and as a consequence are negatively affected by isolation.