Abstract
Roads and traffic reduce landscape connectivity and increase rates of mortality for many species of wildlife. Species that glide from tree to tree may be strongly affected by roads and traffic if the size of the gap between trees exceeds their gliding capability. Not only are wide roads likely to reduce crossing 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 southeast Australia using radio-tracking. The proportion of gliders crossing one or both roadways of a freeway where trees 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 proportion that crossed one or both roadways at the freeway with trees in the median (67%), whereas only a single male (6%) crossed the freeway where trees were absent from the median. The frequency of crossing for each individual was also similar at control sites and freeway sites with trees in the median. The almost complete lack of crossing at sites where trees were absent from the median was attributed to the wider gap in canopy (50 – 64 m vs. 5 – 13 m at sites with trees in the median). This suggests that traffic volume, up to 5,000 vehicles per day on each roadway, and the other characteristics of the freeway that the authors studied are not in themselves complete deterrents to road crossing by squirrel gliders. This study demonstrates that retaining and facilitating the growth of tall trees in the center median of two-way roads may mitigate the barrier effect of roads on gliders, thus contributing positively to mobility and potentially to connectivity. This information will be essential for the assessment of road impacts on gliding species using population viability models.
Highlights
Road ecology has recently emerged as a bona fide subdiscipline within ecology and there has been increasing interest in the integration of findings of scientific research into decision making in transportation planning (Roedenbeck et al 2007)
Intersections were selected as the focus for study because squirrel glider activity is higher at intersections than straight sections of linear habitat and road crossing is more likely
A total of 2155 fixes were obtained from 58 squirrel gliders (29 males and 29 females) that were fitted with radio-collars
Summary
Road ecology has recently emerged as a bona fide subdiscipline within ecology and there has been increasing interest in the integration of findings of scientific research into decision making in transportation planning (Roedenbeck et al 2007). Numerous studies have documented the adverse impacts of roads on wildlife (see reviews by Coffin 2007, Fahrig and Rytwinski 2009, Benítez-López et al 2010), which include habitat loss, mortality due to collision with vehicles, resource inaccessibility, and population subdivision (Jaeger et al 2005). It is essential to quantify the barrier effect of roads on species occurring in fragmented habitat to determine any impact on population viability. Information on crossing behavior can be used to provide recommendations for optimal road planning and potential mitigation structures, and information for population viability models (Kramer-Schadt et al 2004, Jaeger et al 2005).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
