“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.