2017-03-07 Planning & Environment Committee Agenda

PLANNING & ENVIRONMENT COMMITTEE MEETING AGENDA                                       7 MARCH 2017


2.    VEGETATIVE BUFFER ZONE
Vegetation was cleared for 10-15 metres between the rear of residential properties and the
commencement of the roosting habitat to shift the presence of flying-foxes away from the trees
overhanging properties. The area along the Western boundary was selected as it has the highest
level of conflict, with flying-foxes consistently utilising the south-western corner of the park in hot
weather due to the increased shade, and also due to pre-existing stormwater infrastructure
occurring in this area. Therefore, should any future maintenance be required, works will not
disturb habitat.
In some sections of the buffer zone, patches of vegetation were retained along the rear of
properties to provide a visual barrier for residents, to avoid direct vision of the flying foxes. At
these points the buffer size is at least 10 metres
3.    SPRINKLER DETERRENT SYSTEM
A trial sprinkler deterrent system was installed along the south-western perimeter to disturb and
deter roosting flying-foxes in the area they most frequently utilise. Eight sprinklers were installed
in the canopy along 129 metres on the perimeter of Trial section 2, shown in Figure 1. The
sprinklers were timed to activate for 30 seconds at 8:00am every Monday, Wednesday, Friday
and Saturday for the first week to determine efficacy. This timing is within the guidelines of the
Department of Environment and Heritage Protection (DEHP) Code of Practice for the Flying-fox
roost management permit.
The initial trial was performed with two members of Flying Fox Rescue and Release to oversee
the impact of the sprinkler system on the wellbeing of the flying-foxes. Upon commencement of
sprinkler use, flying-foxes within the buffer zone responded by flying up and moving 20-25 metres
away from the sprinkler before quickly settling again. Most moved directly parallel to the spray
arc, while some moved 5-10 metres further north, only to shift parallel when the next sprinkler in
the sequence activated.
The timing of the sprinkler sequence has subsequently been manipulated after consultation with
several bat carers as to the optimal times to reduce potential for accidental dispersal and risk of
heat stress. A start time of 7:30am was considered optimal as this allows appropriate time for the
flying-foxes to settle within the roost and ensure only those within the spray arc are disturbed and
the entire colony is not dispersed. Similarly, this ensured that all noise from disturbances would
not affect residents too early in the morning.
As yet, there has been no habituation to the sprinkler deterrent system and it remains an
effective management technique. Should it occur, the sequence and timing of activation will be
manipulated.
The south western area of Wallace Park (the area adjacent to section 1 on the map) has been
the most highly utilised area within the park and extends across into the hospital grounds. The
densest understorey exists within this area and the flying-foxes have primarily occupied these
areas as their maternity camps and for cooling throughout the hottest months. Based on the
proximity of this area to both the largest congregation of flying-foxes and also the hospital
grounds, an extension of the SDS should be carefully implemented and continually monitored.




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