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

level of traffic calming involving road closure during peak periods of fauna movement, was the most
successful at road-kill reduction.
Table 1 Impact of traffic calming on road-kill (Jaarsma et al. 2006)

 Traffic calming measure                                        Impact to road-kill compared to base situation
 Mainly legal measures, including a rigid enforcement of the    Slight improvement in the traversability, but this is still
 present speed limit of 80 km/hr                                worse than in the present situation
 Implementation of a traffic-calmed area with a legal speed     Reduces road-kill by about one third
 limit of 60 km/hr and a few speed bumps
 Implementation of a traffic-calmed area with more              Reduces road-kill by more than 50%
 measures to reduce speed and a narrowed pavement
 Implementation of a traffic-calmed area with limited           Reduces road-kill to about 10% of the current level
 access: access for local residents only between 7 pm and
 7 am (assumes nocturnal wildlife movements are critical)



Mitigation measures are often applied to major roads and minor roads are left unmitigated. van Langevelde
et al. (2009) argue that the success of mitigation measures increases considerably when minor roads are
included in the planning and that the effects of minor and major roads should be mitigated together. The
authors propose an integrated strategy that considers regional networks of both major and minor roads so
that positive effects of mitigation efforts at one location will not be undone by unintended effects elsewhere.

Surveys of koala populations need to be completed in the early stage of planning at a scale providing
sufficient detail to enable strategic placement of mitigation measures, especially crossing devices, to
maximise the likelihood of use by koalas.

3.3.2.          Optimisation
Decision science is a rational and transparent way of determining the best action given multiple objectives
that can be applied to find the ‘optimal’ decisions for conservation efforts within social and financial
constraints (Polak et al. 2014). A variety of tools and approaches have been developed to assist managers
and policy makers (Possingham et al. 2001; McDonald-Madden et al. 2008; Wilson et al. 2009). Polak et al.
(2014) applied the method to a koala population living in habitat patches separated by roads on the Koala
Coast to find the best solution to mitigating the impacts of the roads for a range of possible costs. The study
illustrated the trade-off between potential biodiversity benefits and economic cost by exhaustively exploring
all possible combinations of three mitigation actions (fencing without wildlife passage, fencing with wildlife
passage and no action) over the study area. The study shows that the best solution for the case study depends
on the available budget. This systematic approach can assist decision-makers to make informed decisions
about where and how to invest funds for cost-effective conservation investment (Polak et al. 2014). It should
be noted that the study did not account for genetics and this may be an area for improvement.

3.3.3.          Monitoring and Maintenance
Investment in mitigation measures must be supported by ongoing monitoring and maintenance plans to
ensure that the infrastructure can continue functioning as intended. As an example, Bond and Jones (2008)
found that fencing was effective until openings were created in the fence. Koalas have been observed
climbing over fences where vegetation was allowed to grow adjacent to the fence and squeezing through
very small gaps under fences.




Koala Infrastructure Audit & Feasibility Report                                                                               Page 17

Noosa Council
17SUN-0087/1700860