Recolonisation of powerline corridor vegetation by small mammals : timing and the influence of vegetation management

Powerline corridors through forested ecosystems have been criticised due their potential to fragment the landscape and facilitate the intrusion of undesirable species into natural areas. This study investigates the effects of vegetation management (slashing), on: (1) timing of small mammal recolonisation; (2) vegetation characteristics that drive small mammal responses; and (3) the point where corridor resources are sufficient to provide functional habitat for native species. Small mammal trapping was undertaken within Bunyip State Park, Australia, across three sites, once a month from January 2001 to May 2002 and every 2 months thereafter until January 2004. Changes in vegetation around each trap station were assessed annually in the forest and bi-annually in the corridor. Principal components analysis on the vegetation structural complexity values produced factors for use in species abundance models. Native small mammal species recolonised the corridor 1.5–3.5 years after management and the corridor supported a breeding population of small mammals around 2.5 years post-management. Males however, generally recolonised the corridor first, resulting in a sex-biased population in these areas. Species corridor habitat models for five native and one introduced species suggested cover and shelter were more important in determining corridor use than plant species per se. Powerline corridors have the potential to create a mixture of different successional stages, enhancing habitat availability for many species. However, the intensity of current management needs to be reduced and an integrated approach to management needs to be undertaken if powerline corridors are to continuously provide habitat for native small mammal species.