摘要：Roads and traffic reduce landscape connectivity and increase rates of mortality for manyspecies of wildlife. Species that glide from tree to tree may be strongly affected by roads and traffic if thesize of the gap between trees exceeds their gliding capability. Not only are wide roads likely to reducecrossing rates, but mortality may also be increased if gliders that do cross have poor landing opportunities.The road-crossing behavior of 47 squirrel gliders (Petaurus norfolcensis) was investigated in southeastAustralia using radio-tracking. The proportion of gliders crossing one or both roadways of a freeway wheretrees were present or absent from the center median was compared to that at single-lane country roads(control). The proportion of gliders crossing the road at control sites (77%) was similar to the proportionthat crossed one or both roadways at the freeway with trees in the median (67%), whereas only a singlemale (6%) crossed the freeway where trees were absent from the median. The frequency of crossing foreach individual was also similar at control sites and freeway sites with trees in the median. The almostcomplete lack of crossing at sites where trees were absent from the median was attributed to the wider gapin canopy (50 – 64 m vs. 5 – 13 m at sites with trees in the median). This suggests that traffic volume, upto 5,000 vehicles per day on each roadway, and the other characteristics of the freeway we studied are notin themselves complete deterrents to road crossing by squirrel gliders. This study demonstrates that retainingand facilitating the growth of tall trees in the center median of two-way roads may mitigate the barriereffect of roads on gliders, thus contributing positively to mobility and potentially to connectivity. Thisinformation will be essential for the assessment of road impacts on gliding species using population viabilitymodels.
