Figure Legends
Figure 1: Map of roost sites included in the study. Grey shading
indicates urban land cover of dense human habitation (as per Schneider,
Friedl & Potere 2009) and grey circles are locations of flying-fox
roosts. Circles show 45km foraging radii from roost study sites (as per
Giles et al. 2018). GIS land-cover data was downloaded from
Natural Earth (2020) and flying-fox roost locations obtained from the
National Flying-Fox Monitoring Program (2017).
Figure 2: Occupancy of subplots across survey period, for surveys when
at least one bat was present. A) shows the total number of bats per
subplot, and B) shows the proportion of surveys the subplot was
occupied. Facets/colour indicates separate roost sites. “C” indicates
roosts that have features of contemporary roost types (see Table 1).
Note that construction works at the ‘Avondale’ roost during the survey
caused the bats to shift their roosting location, such that only one
subplot was utilised thereafter.
Figure 3: Occupancy of subplots in ‘core’ and ‘peripheral’ areas, shown
by average total number of bats per occupied subplot across the survey
period. Data is filtered to show numbers of bats when subplots were
occupied (i.e. unoccupied subplots are removed). ‘Core’ subplots were
identified as those occupied in at least 80% of surveys (when bats
present at the roost), and ‘peripheral’ subplots as those occupied less
than 80% of the time. A) Shows areas split by roost site (facet and
colour), and B) shows all roosts combined. Area displayed in subplot has
been cropped to remove extreme outliers. “C” indicates roosts that
have features of contemporary roost types (see Table 1).
Figure 4: Distance from roost centre and occupancy of bats, shown by the
average total number of bats per occupied subplot during the survey
period. Data is filtered to show numbers of bats when trees are occupied
(i.e. unoccupied subplots are removed). Roost centre is calculated for
each survey as the centroid of the roost area at the time of the survey.
Distance from the centre is calculated as the mean distance of trees in
each subplot from this centroid, scaled by the maximum observed distance
value per session. A) shows values per species (line type) split by
roost (facets); and B) shows species and roost combined. Trend line is
by loess fit (local polynomial regression fit) with standard error bands
(grey shading). “C” indicates roosts that have features of
contemporary roost types (see Table 1).
Figure 5: Relationship between total roost abundance (x axis) and total
roost area (y axis) for each roost site. A) shows relationship split by
roost (facets) and B) shows relationship with roosts combined. Trend
line is by loess fit (local polynomial regression fit) with standard
error bands (grey shading). Note that trend lines could not be fitted
for all sites and are omitted. “C” indicates roosts that have features
of contemporary roost types (see Table 1).
Figure 6: Co-occupation of subplots (A) and individual trees (B) by
species. Total subplots/total trees observed are shown in text labels
and include subplots/trees across sessions where every bat species in
the species comparison were present. (e.g. for the black and grey-headed
flying-fox comparison, only sessions where both black and grey-headed
flying-fox were present were included in the subplot/tree tally). ‘BFF’
refers to black-flying-fox, ‘GHFF’ grey-headed flying-fox and ‘LRFF’
little red flying-fox. Confidence intervals are binomial, calculated
with a Wilson test.
Figure 7: Difference in roosting height per species, over time. Fill
shows average roosting height range per species (minimum height to
maximum height). Fill boundaries (minimum and maximum curves) are by
loess fit (local polynomial regression fit). A) shows relationship split
by roost (facets) and B) shows relationship with roosts combined. In A),
dashed line represents the average canopy height per site; for roost
sites where species occupy distinctly different areas (‘Clunes’ and
‘Lismore’), canopy height is split by areas the species predominantly
occupy. “C” indicates roosts that have features of contemporary roost
types (see Table 1). Note that height data are taken from the tree
subset only (up to N=60 per roost site), and that trend lines could not
be fitted for all site by species combinations and are omitted.
Figure 8: Proportion of male bats per occupied tree versus distance of
tree from the roost centre, scaled by the maximum distance value
observed per session. A) shows values per species (row facet) split by
roost (column facet); B) shows combined species value pooled by roost.
Trend line is by loess fit (local polynomial regression fit) with
standard error bands (grey shading). ‘BFF’ refers to black-flying-fox,
‘GHFF’ grey-headed flying-fox and ‘LRFF’ little red flying-fox. “C”
indicates roosts that have features of contemporary roost types (see
Table 1).
Figure 9: Different scales of bat abundance measures through time. A)
shows total roost abundance; B) shows total roost area; C) shows the
proportion of occupied trees per subplot; D) shows the total abundance
of occupied subplots. Total roost abundance is measured by an index
score of abundance: 1 = 1-499 bats; 2 = 500-2,499 bats; 3 = 2,500 -
4,999 bats; 4 = 5,000 - 9,999 bats; 5 = 10,000 - 15,999 bats; 6 = 16,000
- 49,999 bats; and 7 = > 50,000 bats.
Figures