“Some areas of permanent camps are more consistently occupied
(’core areas’) than others” & “‘Core areas’ are more densely occupied
than ‘peripheral areas”’ & “Roost area fluctuates with total
abundance”
Variability in the usage and occupation of areas within roosts have been
highlighted in management documents (e.g. SEQ Catchments 2012). This
includes more persistent usage of ‘core’ areas, higher occupation of
‘core’ areas, and variability in the roost perimeter (reflecting
expansion and contraction from the core area). All existing literature
(to our knowledge) and the new data from our study support these
understandings. We would note however, the distinction between a
‘core/peripheral’ roost area and a ‘central/edge’ roost area. We defined
the core area based on consistency of occupation, not spatial location.
Areas identified to be ‘core’ were not necessarily in the centre of the
roost (see location of roost centroid relative to the roost perimeter
and surveyed subplots, in Appendix S3). This distinction has not
necessarily been made in literature and management plans to date but has
important implications for the interpretation of ‘core’ roosting areas,
and management recommendations specific for ‘core/central’ or
‘peripheral/edge’ areas. For example, it cannot be assumed that buffer
creation via vegetation removal from the roost edge will not affect a
‘core’ area of bat roosting, and so will not have a substantial impact
of flying-foxes. Management activities should be prescribed for specific
zones in roosts, based on prior monitoring of the roost, and recognising
the ecological importance of different areas (Pallin 2000; Ku-ring-gai
Council 2018). In addition, prior monitoring of core/peripheral roosting
areas will be important to inform the location and potential
effectiveness of buffer creation. Given the potential for roost area to
fluctuate with abundance, creation of buffers via vegetation removal may
reduce the area of normal roost habitat available, and result in an
expansion into new areas when flying-fox numbers increase (as noted in
Currey et al. 2018). The prescription of buffers should be
planned with care to avoid unintended outcomes during periods of high
population abundance.