2019-03-12 P&E Agenda - Item 5 - Attachment 2 - Koala Infrastructure & Feasibility Report

     mortality in anurans, a group of species vulnerable to road mortality, than provision of fauna crossing
     infrastructure. The authors concluded that the priority for mitigation of road mortality should be
     installation of fencing or other structures that exclude fauna from the road surface.
•    Koala-specific studies have found installation of floppy-top fencing along major roads in New South Wales
     to reduce koala road-kill (Taylor & Goldingay 2003; Lassau et al. 2008; Hayes & Goldingay 2009).
•    Dexter et al. (2016) examined whether retrofitting existing road structures at six sites facilitated safe
     passage for koalas across roads. During the 17 month monitoring period, a single sub-adult male was
     confirmed to have approached a study road on 38 occasions and cross the road on 19 of these occasions.
     His road crossings occurred before and during construction of the koala overpass and fauna-exclusion
     fences. No road crossings were detected after completion of the koala overpass and fauna-exclusion
     fences.
•    Ascensão et al. (2013) applied a simulation model to the stone marten to assess the relative performance
     of fencing and passage construction to mitigate the impacts of wildlife–vehicle collisions under different
     rates of road mortality. The study predicts that fences are more effective than passages at mitigating the
     effects of road mortality on abundance and, under most circumstances, are more effective than passages
     at reducing genetic differentiation. The authors suggest the ability of fencing to eliminate road mortality
     increases genetic diversity, thereby slowing differentiation across the road, and argue that partial fencing
     of roads alone may often be the best and most cost-effective management option for road mitigation.

Design considerations
• Smaller species may pass through fences (Bond & Jones 2008) and when designing for multi-species
   applications, barriers built into the base of fences may improve its ability to guide small mammals and
   herpetofauna (Taylor & Goldingay 2003).
• Fencing has limited application to stretches of road where driveways occur regularly (Goldingay &
   Dobner 2014).
• Fencing in the absence of crossing structures can act as a barrier to natural movements and contribute
   to habitat fragmentation. Where movement across roads is required to enable population processes to
   continue (Lee et al. 2010), fences must be complemented by crossing structures. Fencing should extend
   far enough to either side of a crossing structure to promote guidance to the structure (Glista et al. 2009).
• Where choices must be made due to limited mitigation funds and road mortality has a stronger impact
   than the movement barrier effect on both population persistence and genetic diversity of a species, the
   priority for mitigation of road mortality should be installation of fencing or other structures that exclude
   fauna from the road surface (Cunnington et al. 2014).
• Escape routes, such as one-way gates, and refuge poles should be supplied to allow exit from the road
   should a koala venture into a fenced area. Examples of gates that have been designed for other species
   are shown in Plate 1.




Koala Infrastructure Audit & Feasibility Report                                                            Page 9

Noosa Council
17SUN-0087/1700860