Temporal trends in use of fauna-friendly underpasses and overpasses

Abstract

The impact of roads on local biodiversity is a major issue associated with urbanisation. A major arterial road in the southern suburbs of Brisbane, south-east Queensland, was upgraded in 2004–05 from two to four lanes. In an attempt to minimise the impact of the larger road on local wildlife populations, a range of fauna crossing structures were constructed at the site. Monitoring of road-kill was undertaken for 4 months before construction and after the completion of construction. Assessment of the use of two underpasses and a large overpass (‘land-bridge’) started 6 months after construction using sand tracking in underpasses and scat sampling on the land-bridge. An initial 26-week period of intensive monitoring was undertaken from August 2005 to February 2006 followed by monthly monitoring from June 2006 to June 2007. On average, 1–5 tracks per day were detected in the underpasses at the start of the survey, increasing steadily to ~42 tracks per day by February 2006. The monthly survey showed regular use of the underpasses by a wide range of species and species-groups, the most abundant being ‘rodents’, most likely Rattus species, both native and introduced. The land-bridge was also used continuously by three species of macropod (red-necked wallaby, Macropus rufogriseus; swamp wallaby, Wallabia bicolor; and eastern grey kangaroo, Macropus giganteus) with brown hare (Lepus capensis) becoming increasingly common in summer 2006. The exclusion fencing was extremely effective in preventing most road-kill, at least of larger species, except following human-related breaches in the fence.

Full text

CSIRO PUBLISHING
www.publish.csiro.au/journals/wr Wildlife Research, 2008, 35, 103–112
Temporal trends in use of fauna-friendly
underpasses and overpasses
Amy R. BondA and Darryl N. JonesB,C
AApplied Road Ecology Research, Griffith School of Environment, Griffith University, Nathan,
Qld 4111, Australia.
BCentre for Innovative Conservation Strategies, Griffith University, Nathan, Qld 4111, Australia.
CCorresponding author. Email: d.jones@griffith.edu.au
Abstract. The impact of roads on local biodiversity is a major issue associated with urbanisation. A major arterial road
in the southern suburbs of Brisbane, south-east Queensland, was upgraded in 2004–05 from two to four lanes. In an
attempt to minimise the impact of the larger road on local wildlife populations, a range of fauna crossing structures were
constructed at the site. Monitoring of road-kill was undertaken for 4 months before construction and after the completion
of construction. Assessment of the use of two underpasses and a large overpass (‘land-bridge’) started 6 months after con-
struction using sand tracking in underpasses and scat sampling on the land-bridge. An initial 26-week period of intensive
monitoring was undertaken from August 2005 to February 2006 followed by monthly monitoring from June 2006 to June
2007. On average, 1–5 tracks per day were detected in the underpasses at the start of the survey, increasing steadily to
~42 tracks per day by February 2006. The monthly survey showed regular use of the underpasses by a wide range of species
and species-groups, the most abundant being ‘rodents’, most likely Rattus species, both native and introduced. The land-
bridge was also used continuously by three species of macropod (red-necked wallaby, Macropus rufogriseus; swamp
wallaby, Wallabia bicolor; and eastern grey kangaroo, Macropus giganteus) with brown hare (Lepus capensis) becoming
increasingly common in summer 2006. The exclusion fencing was extremely effective in preventing most road-kill, at least
of larger species, except following human-related breaches in the fence.
Introduction
Roads often have major impacts on faunal populations inhabit- fencing, and therefore to increase connectivity of habitats and
ing surrounding areas. Such impacts may be due to attributes of facilitate wildlife movements, numerous wildlife overpasses
the road, including traffic volume and road width, and may be and underpasses have been constructed. The first purpose-built
direct (such as fatalities and the severing of routes of movement) wildlife passages were in Europe and North America in the mid-
and indirect (such as via disturbance due to noise and pollution) 1900s (Forman et al. 2003) and a wide range of overpasses and
(Bennett 1991; Forman et al. 2003). The intrusion of a road underpasses have since been introduced on new and existing
through previously intact areas can act as a major barrier to roads across both continents, with clear evidence of use for
movements and pose a significant risk to animals that do certain species (see e.g. Foster and Humphrey 1995; Yanes et al.
attempt to cross (Oxley et al. 1974; Bennett 1991; Jones 2000; 1995; Clevenger and Waltho 2000; Mata et al. 2005; Goosem
Forman et al. 2003). Forest remnants, especially those in areas et al. 2006).
affected by urbanisation, are often surrounded or bisected by It has only been in recent years, however, that Australian road
roads, presenting a major obstacle to animals attempting to dis- authorities have started to construct underpasses and overpasses
perse or move between remnants. As a result, local populations to connect forest remnants divided by roads (Hunt et al. 1987;
of fauna frequently become marooned in increasingly isolated Goosem 2001; Goosem et al. 2001). Wildlife crossing struc-
patches, inevitably increasing their susceptibility to decline and tures have now been purposefully built in a range of locations
extirpation (Bennett 1991; Jones 2000; Goosem 2001; Taylor and conditions, for example, in the Victorian Alps (specifically
and Goldingay 2004). for the mountain pygmy-possum, Burramys parvus) (Mansergh
In response to community concerns over increasingly con- and Scotts 1989), at Brunswick Heads in northern New South
spicuous road-kill and a desire to enhance connectivity between Wales (Taylor and Goldingay 2003), and in the Atherton
forest fragments, road engineers have begun to include a variety Tablelands in northern Queensland (Goosem et al. 2001, 2006).
of mitigation measures in their designs. Initially, roadside exclu- In 2004, a diverse array of fauna crossing and road-kill mitiga-
sion fencing was adopted, with some success in reducing tion structures were constructed on Compton Road in south-
wildlife-vehicle collisions (Clevenger et al. 2001; Forman et al. eastern Queensland.
2003). However, these fences often create an even greater Compton Road is a major east–west arterial located in the
barrier between habitats when used as the only method to south of the Brisbane metropolitan area. It services some of the
protect local wildlife populations (Bennett 1991). In order to fastest growing urban areas in Australia and has experienced
reduce the barrier effects of roads and roadside exclusion increasingly heavy traffic loads over the past decade. One
© CSIRO 2008 10.1071/WR07027 1035-3712/08/020103

104 Wildlife Research A. R. Bond and D. N. Jones
Fig. 1. Site map showing approximate locations of land-bridge and under-
passes at Compton Road, southern Brisbane.
section of Compton Road separates the nationally significant
Karawatha Forest from Kuraby Bushland immediately to the
north. Both areas are crucial components of the Greenbank
Corridor, a series of relatively contiguous areas of subtropical
bushland recognised as being of critical importance to the main-
tenance of biodiversity in a region experiencing exceptional
population pressure (Veage and Jones 2007).
During 2004, 1.3 km of Compton Road dividing the two
areas of bushland (Karawatha and Kuraby) were upgraded from
two to four lanes. Concerns over the impact of this larger road
on the integrity of Karawatha Forest resulted in extensive con-
sultations of the design of a range of mitigation features to be
integrated into the upgrade constructions (see Chenoweth 2003;
Mack 2005). Completed in early 2005, this site has one of the
largest concentrations of fauna-crossing structures in a single
location anywhere in the world (Fig. 1). These include: special-
ised road-side exclusion fencing; two faunal underpasses with
‘wildlife furniture’; three wet culverts with an artificial pond; a
series of ‘glider poles’ (erected along the length of the land-
bridge); three arboreal rope bridges connecting the tree canopy
on either side of the road; and a ‘land-bridge’ (overpass) span-
ning the entire width of the new road (Fig. 2).
Fig. 2. The land-bridge over Compton Road, southern Brisbane, also
showing exclusion fencing (photograph: D. N. Jones, taken April 2005).
Several surveillance projects are being conducted to assess
the effectiveness and use by wildlife of these various structures
(see Veage and Jones 2007). A significant part of the motivation
to obtain reliable and systematic data on the use of these facili-
ties by fauna related to ongoing scepticism on the efficacy of
such expensive constructions. Despite numerous North
American and European studies (van der Ree et al. 2007
reviewed 123 such studies) demonstrating regular use of both
purpose-built and existing culverts by a wide variety of species,
in Australia it is not unusual to hear claims that such structures
simply are ineffective or to read statements suggesting that these
expensive features primarily benefit feral species, particularly
mammalian predators (see Anon. 2006).
An important additional concern is the likelihood that con-
siderable periods of time may be required before local animals
are sufficiently familiar with the structures to use them (Hunt
et al. 1987). For example, Clevenger and Waltho (2005) found
that individuals of some species, especially large mammals such
as elk, Cervus elephus, may require 2–4 years to ‘adapt’ to the
presence of such structures. In the Northern Hemisphere, road
ecologists frequently warn against expectations of early use of
passages, especially in less disturbed areas (Mata et al. 2005).
As Australian local governments and road agencies show
increasing interest in the mitigation of the ecological impacts of
roads, it is crucial that reliable monitoring data is readily avail-
able, especially of long-term patterns of use. Finally, it is impor-
tant to discern the extent to which animals are actually using the
structures to cross the road, as a crucial aim of the provision of
the facilities is the overcoming of the road’s barrier effect
(Bennett 1991); crossings are necessary for gene flow and the
reconnection of populations is a fundamental element for claims
of success (Aars and Ims 1999).
Here we report on the monitoring of the use of two under-
passes and the land-bridge by terrestrial fauna at Compton
Road, as evidenced by sand tracking (for the underpasses) and
systematic scat sampling (for the land-bridge). The monitoring
was undertaken in two periods: an initial intensive 26-week
study started 6 months from the end of construction (August
2005 – February 2006); and 13 monthly surveys (June 2006 –
June 2007). Together, these two phases spanned a total of
29 months. In addition, to assess the effectiveness of the exclu-
sion fencing, we compared the amount of road-kill for the
4 months immediately before the commencement of work with
that following the completion of construction.
The aims of this study were to:
(1) assess the use of the two faunal underpasses by terrestrial
vertebrates, as indicated by sand tracking, and determine the
extent to which animals used them to complete crossings;
(2) assess the use of the land-bridge by medium to large terres-
trial mammals, as indicated by scat counts; and
(3) compare road-kill rates for large animals on the road before
and after the construction of the exclusion fence.
Methods
Study site
Karawatha Forest is a large remnant forest of ~950 ha situated
on the southern fringe of Brisbane (Stewart 1997). Its vegetation
cover consists mainly of dry eucalypt forest and woodland with

Use of fauna underpasses and overpasses Wildlife Research 105
heath understoreys and contains lagoon systems that provide
important habitat (Kordas et al. 1993). The forest contains 324
plant species and supports a wide range of native vertebrate
species (Kehl and Corben 1991; Kordas et al. 1993). The north-
ern boundary of the forest is separated from Kuraby Bushland
by Compton Road; this area consists of similar vegetation to that
of Karawatha Forest and contains many of the same fauna
species (Stewart 1997). The entire study was conducted during
a prolonged drought that affected the entire south-east
Queensland region.
Two specifically designed fauna underpasses were con-
structed under Compton Road during the upgrade in 2004. Both
are 2.4 m high, 2.5 m wide and 48 m long and contain three
levels: a lower cement level for water flow; a raised cement level
with rocks as ‘furniture’; and two shelves, a small wooden shelf
attached to the wall of the underpass and a raised half-log
railing, both of which run the full length of the underpass
(Fig. 3). The latter innovative component of the design was
included in an attempt to facilitate the passage of smaller
species without them having to move along the relatively open
area of the underpass floor. The raised cement level is 1.6 m
wide and 0.4 m above the ground, leaving a height of 2 m from
this level. The lower cement level and wooden shelf are 0.9 m
and 0.25 m wide respectively.
The two faunal underpasses (A and B) are structurally iden-
tical except for a large pipe passing through the middle of
underpass A and a drainage grate in the ceiling. The pipe
inhibits crossings through the underpass by animals using the
shelf (but does not impede passage along the concrete surface
beneath), while the grate allows some light into the underpass
about half way along its length. Underpass A is also positioned
immediately beside three wet culverts and a well vegetated
artificial pond. Low shrubby vegetation occurs very close to
the Karawatha Forest entrance of Underpass A and both
entrances of Underpass B. The Kuraby Bushland entrance of
Underpass A, however, opens onto a concrete apron next to an
artificial pond surrounded by dense reed-banks and other
aquatic plants.
Fig. 3. Interior of Under pass A showing internal structure, raised shelf and
‘furniture’ (photograph: D. N. Jones, taken April 2005).
The land-bridge is hourglass-shaped (see Forman et al.
2003) with an arc length of 70 m, a base width of 20 m and a
mid-width of 15 m (Fig. 2). The slope of the batters towards the
forest on either side is 1:3 but 1 : 2 towards the road (Mack
2005). The top of the structure is 8 m above the road, with 5.4 m
clearance within each tunnel. The roadside exclusion fence con-
tinues unbroken over the land-bridge from the forest edges on
either side of the road. A thick layer of mulch covers the span
and a large number of local shrub, trees and grass species have
been planted across the bridge to provide cover for wildlife
using the structure. The exclusion fence is 2.48 m high and con-
structed of rubberised metal mesh extending directly into the
ground for a depth of 5 cm. A 1-cm-thick sheet of industrial
rubber is attached to the base of the fence to a height of 48 cm
and inserted slightly into the soil, forming a continuous barrier
along the entire length of the fence. A solid sheet of rolled metal
59 cm in width, intended to deter animals attempting to climb
the mesh, is attached to the fence on the forest side with the
lower edge 1.38 m above the ground. Human disturbance of the
structures and immediate vicinity is minimal other than
weekend trail bike use of the lower slopes of the Kuraby side of
the land-bridge.
Sand tracking (underpass monitoring)
Sand strips were established inside both ends of the two faunal
underpasses, ~1–2 m from the edge to minimise disturbance
from rain or wind. The sand strips were ~1–2 cm thick, 1 m wide
and covered the entire width of the raised section of the under-
passes. Smaller sand strips were also set up on the shelves; these
were ~0.5 cm thick and 0.5 m wide.
The sand was smoothed using a combination of the back of a
nail rake (as recommended by Taylor and Goldingay 2003) and
the flat part of a hand spade on the morning of a monitoring day,
and checked for prints early the following morning. Monitoring
was undertaken intensively (twice weekly) from 9 August 2005
to 6 February 2006 for 26 weeks and monthly from June 2006 to
June 2007, providing a period of monitoring spanning 29 months
with a gap between March and June 2006. Intensive surveys of
both underpasses were undertaken for a total of 26 weeks,
although only 19 weeks of underpass data were able to be used
in the analyses due to disturbance by rain, wind or humans.
The underpass, sand strip, direction of movement and
species identity of all visible tracks (spoor) detected in the sand
strip were recorded. A full crossing of the underpass was
assumed when tracks reliably identified as the same taxon, same
size and moving in the same direction, were discerned in the
sand strips at both ends of an underpass on the same date.
Tracks were identified as accurately as possible using the
information and diagrams in Triggs (2004) and Morrison (1981)
and measurements given in Menkhorst and Knight (2004). All
tracks were assigned to one of 16 categories or as an unknown.
The categories were: rodent, house mouse, dasyurid, bandicoot,
possum, wallaby, echidna, cat, dog, hare, agamid lizard, large
skink, snake, small bird and other bird (see Table 1 for details of
likely mammal species). For certain categories (e.g. rodent),
unequivocal identification to species was not possible; instead,
a list of the most likely species was developed, based on species
known to occur in Karawatha Forest (Karawatha Forest
Protection Society, unpubl. data).

106 Wildlife Research A. R. Bond and D. N. Jones
Scat collections (land-bridge monitoring)
Assessment of the use of the land-bridge was limited to species
producing detectable scats. Weekly scat collections were con-
ducted on the land-bridge for 26 continuous weeks, commenc-
ing on 10 August 2005 and concluding on 8 February 2006. An
additional ‘snap-shot’ sample was undertaken for two weeks
during June 2007. The land-bridge was divided into three zones:
Zone 1 (the southern slope of the bridge side facing Karawatha
Forest), Zone 2 (the flat top and central section of the bridge)
and Zone 3 (the northern slope facing Kuraby Bushland). All
scats were collected by one investigator (ARB). Prior to the sys-
tematic collection of scats, intensive searches of the land-bridge
were conducted to facilitate collecting efficiency. Scats were
collected from each zone by crossing diagonally across the zone
four times and constantly searching either side of the chosen
route. As Zones 1 and 3 were ~30% larger in area than Zone 2
(675 m2 versus 450 m2), the time devoted to searching for scats
was scaled accordingly: 15 min for Zones 1 and 3, and 10 min
for Zone 2.
All scats were collected in separate zip-lock bags labelled
with the date and zone, and identified using Triggs (2004),
Morrison (1981) and reference samples collected from known
species of those likely to be found in Karawatha Forest. The
identification and abundance of scats collected from each zone
was recorded. Scats from feral cats, dogs and foxes proved too
difficult to reliably differentiate so were pooled into the single
category of ‘feral carnivore’.
Road-kill surveys
A 4-month survey of the section of Compton Road to be
upgraded was undertaken twice weekly until immediately
before the start of construction activity associated with the
upgrade (April–July 2004). Surveys of the road were not possi-
ble during construction but recommenced in the first week fol-
lowing the end of construction (February 2005). Since that time,
road-kill surveys were undertaken weekly until June 2007, pro-
viding consistent monitoring for a total of 29 months after con-
struction. The initial survey was conducted on foot with the
observer walking along both sides of the road. In the post-
construction phase, Brisbane City Council health and safety
concerns limited these surveys to observations from a vehicle
driven at the speed limit (70 km h−1) along the road in both
directions during the early morning (0500–0630 hours). All
birds, mammals and reptiles larger than a blue-tongued skink,
Tiliqua scincoides, were recorded. All specimens were identi-
fied to species where possible but were not removed or exam-
ined. However, location details were compared on each survey
to ensure that no specimens were counted more than once. It is
acknowledged that the change in the methods used for road-kill
monitoring significantly limited the comparability of the data
collected before and after construction. This was especially
likely to bias the detectability of smaller taxa, most importantly
resulting in an underestimation of these animals during the post-
construction period.
Data analysis
For all analyses comparing the two faunal underpasses, weekly
numbers of tracks and taxa were used by pooling the two days
of surveys for each week. A Pearson’s correlation was used to
assess the relationship between numbers of tracks or taxa and
time. Student’s t-tests were conducted to compare the mean
abundance of tracks and the number of taxa (categories)
obtained weekly for the two underpasses.
Analyses performed on the scat-collection data were similar
to that performed on the sand-tracking data. A Pearson’s corre-
lation between number of weekly scats collected and week was
conducted and an analysis of variance was conducted on the
overall abundance of scats and on the number of taxa (species)
to compare whether all zones are being used equally by wildlife.
Finally, a comparison of the proportions of taxa using the land-
bridge over equivalent two-week periods during 2006 and 2007
was performed using a contingency test (Chi-square).
Results
Fauna presence in underpasses
A wide range of mainly small species was detected in both
underpasses throughout the study. A total of 1141 tracks of
vertebrates were observed, 966 during the 26 weeks of inten-
sive surveys and a further 175 during the 13 monthly surveys
(Table 2). The initial surveys in August 2005 yielded ~1–5
tracks per day but presence increased steadily thereafter,
peaking at ~42 tracks per day at the end of Week 26 in January
2006 (Fig. 4). The correlation between weekly track detections
and time since monitoring began was highly significant
Table 1. Mammal taxa categories associated with tracks identified in sand plots with most likely species listed along with other possible species
known to occur locally
Mammal taxa Most likely species Other possible species
category
Rodent Bush rat, Rattus fuscipes; black rat, Rattus rattus Swamp rat, Rattus lutreolus
House mouse House mouse, Mus musculus –
Dasyurid Common dunnart, Sminthopsis murina Common planigale, Planigale maculata; yellow-footed antechinus, Antechinus flavipes
Bandicoot Northern brown bandicoot, Isoodon macrourus –
Possum Common brushtail possum, Trichosurus vulpecula Common ringtail possum, Pseudocheirus peregrinus
Wallaby Red-necked wallaby, Macropus rufogriseus –
Echidna Short-beaked echidna, Tachyglossus aculeatus –
Cat Domestic or feral cat, Felis catus –
Dog Domestic or feral dog, Canis familiaris Red fox, Vulpes vulpes
Hare Brown hare, Lepus capensis –

Use of fauna underpasses and overpasses Wildlife Research 107
Table 2. Total numbers of tracks of vertebrate taxa (see Table 1 for mammal categories) detected in sand plots of Underpasses A and B for
intensive and monthly surveys, with percentage of total of each taxa that made full crossing
Taxa or Intensive surveys (Period 1) Monthly surveys (Period 2) Total tracks
categories Underpass A Underpass B % Under pass A Underpass B % detected
Total No. Total No. crossings Total No. Total No. crossings in both
tracks per track per tracks per tracks per periods
detected day detected day detected day detected day (%)
Rodents 79 0.59 257 1.93 3.6 24 1.85 10 0.77 5.9 370 (32.4)
House mice 59 0.44 25 0.19 21.4 14 1.08 17 1.31 12.9 115 (10.1)
Dasyurids 7 0.05 0 0.00 28.6 4 0.31 6 0.46 0.0 17 (1.5)
Bandicoots 52 0.39 87 0.65 17.3 14 1.08 26 2.00 40.0 179 (15.7)
Possums 9 0.07 2 0.02 18.2 1 0.08 4 0.31 40.0 16 (1.4)
Wallabies 1 0.01 2 0.02 0.0 0 0.00 0 0.00 – 3 (0.3)
Echidnas 1 0.01 1 0.01 0.0 0 0.00 0 0.00 – 2 (0.2)
Cats 6 0.05 27 0.20 48.5 7 0.54 2 0.15 88.9 42 (3.7)
Dogs 10 0.08 0 0.00 40.0 2 0.15 7 0.54 66.7 19 (1.7)
Brown hares 0 0 2 0.02 0.0 0 0.00 1 0.08 0.0 3 (0.3)
Birds 39 0.29 21 0.16 20.0 4 0.31 1 0.08 0.0 65 (5.7)
Reptiles 167 1.26 76 0.57 1.6 13 1.00 1 0.08 0.0 257 (22.5)
Frogs 0 0.00 0 0.00 0.0 2 0.15 14 1.08 62.5 16 (1.4)
Unknowns 17 0.13 19 0.14 5.6 1 0.08 0 0.00 0.0 37 (3.2)
Total 447 3.36 519 3.90 9.9 86 6.62 89 6.85 27.4 1141 (100.0)
(r = 0.88, d.f. = 17, P < 0.0001), indicating a distinct linear
increase in presence in the underpasses through this period of
the survey. The monthly surveys, which started 5 months
later, revealed a similar seasonal pattern, with smaller
numbers of tracks in the winter and peaks of activity in mid-
summer: totals of 30 per day were obtained for January 2007
(Fig. 4).
Overall presence of tracks in the two underpasses was
similar throughout the study (46.3% of all tracks for A, 53.7%
for B during the intensive surveys; 49.1% for A, 50.9% for B
during monthly surveys). Furthermore, the mean (±s.d.) number
of tracks detected in each underpass each day was also similar
during both periods of the survey: 3.36 ± 4.38 and 3.90 ± 7.89
per day during the intensive survey and 6.62 ± 4.52 and 6.85 ±
8.02 for the monthly survey, for A and B respectively. None of
these comparisons were significantly different.
The individual tracks were categorised into 16 taxa groups;
only 37 (3.2%) could not be identified and are included together
as ‘unknown’ (Table 2). The mammal taxa category, the most
likely species and other possible species are listed in Table 1.
(10.1%). The only dasyurid species detected with certainty,
common dunnart, was identified on 17 occasions (1.5%). All of
these small mammals combined accounted for almost half of all
animal tracks observed in the underpasses. Including bandi-
coots, these taxa of medium-sized and small mammals comprise
59.7% of all tracks (Table 2).
The taxa producing the second most common tracks (22.5%:
Table 2) were reptiles, mainly a variety of medium-sized lizards,
all of which were likely to be diurnal. Similarly, 65 (5.7%)
tracks were made by birds of various species. When combined
with the reptiles, largely diurnal taxa made up 28.2% of all
tracks (Table 2).
Cats and dogs (feral or/and domestic) were detected on 42
and 19 occasions respectively, together accounting for 5.4% of
all tracks (Table 2).
Tracks of northern brown bandicoots were the third most
commonly detected (Table 2) and this species exhibited a dis-
tinctly seasonal pattern of presence in the underpasses. Having
been recorded only occasionally during most of the year, the
presence of bandicoots peaked abruptly in mid-summer: seven
were detected on one night in January 2006 and 18 in January
2007. Other medium-sized species were detected far less often:
three times for brown hare and twice for short-beaked echidna.
Larger species such as red-necked wallabies, although common
on the land-bridge (see below), were detected in the underpasses
50
40
The category ‘rodents’ accounted for the largest proportion –
almost one-third – of all tracks detected by the sand tracking
(Table 2). The most likely species to have made these tracks
were an introduced and native Rattus species (black rat and bush
rat) which could not be reliably distinguished (see also Triggs
2004). Tracks of house mouse were also relatively common
No. of tracks (24 h)
30
20
10
0
0 20 40 60 80 100
Week
Fig. 4. Total tracks of all species detected in both underpasses per 24-h
survey, for weeks from start of study. Intensive phase (26 weeks) where
Week 1 = week starting 9 August 2005 to Week 26 = week starting 6
February 2006; monthly phase (13 months) from June 2002 (Week 48) to
June 2007 (Week 100).

108 Wildlife Research
Weekly total no. of scats
120
100
80
60
40
20
0
1 3 5 7 9 11 13 15 17 19 21 23 25
Week
Fig. 5. Weekly total scats collected from all zones of the land-bridge over
26 weeks of intensive phase, August 2005 – February 2006, for weeks from
start of study. Week 1 = week starting 9 August 2005, Week 26 = week start-
ing 6 February 2006.
on three occasions only. Possums, however, were detected in the
underpasses 16 times, with 11 of these being during the initial
19 weeks.
A total of 355 separate tracks were detected in the sand placed
on the shelves in both underpasses, made up of 204 ‘rodents’,
77 house mouse, 53 reptiles, 16 birds, and 5 dasyurids. When
compared with the total number of individuals of each of these
taxa entering the underpasses, these figures indicate that 55.1%
of ‘rodents’, 67.0% of house mouse, 20.6% of reptiles, 24.6% of
birds, and 29.4% of dasyurids used the shelves. Overall, 31.1%
of all tracks were detected on the shelves.
Crossing rates
Full crossings of the road through the underpasses were highly
variable among the taxa and between surveys (Table 2). The
only taxa for which no individuals were detected to have made
crossings were wallabies, echidnas and hares, all of which were
found in relatively small numbers. Excluding the diurnal taxa
(birds and reptiles), the percentage of other taxa crossing the
road through the underpasses varied from 0% to 88.9% during
the two survey periods. Relatively few (3.6% and 5.9% for the
two survey periods respectively) of the otherwise abundant
‘rodent’ category made full traverses of the road compared with
21.4% and 12.9% of house mice respectively (Table 2). Overall,
9.9% of all animals detected in the underpasses during the inten-
sive surveys completed full crossings, compared with 27.4%
during the monthly surveys (Table 2).
A. R. Bond and D. N. Jones
Table 3. Total numbers (and percentages) of scats of vertebrate taxa
collected for the three zones of the land-bridge
Taxa or category Zone 1 Zone 2 Zone 3 Total scats (%)
Red-necked wallaby 133 8 46 187 (14.8)
Swamp wallaby 8 5 3 16 (1.3)
Grey kangaroo 39 3 18 60 (4.7)
Possum 4 0 4 8 (0.6)
Short-beaked echidna 5 0 1 6 (0.5)
Brown hare 262 25 676 963 (76.1)
Introduced predator 21 1 4 26 (2.1)
Total 472 42 752 1266 (100)
Fauna presence on the land-bridge
In total, 1266 vertebrate scats were collected on the land-bridge
over the intensive survey of 26 weeks. There was no linear
relationship between the total number of scats collected weekly
and time since monitoring began (r = –0.3182, P = 0.5241)
(Fig. 5).
The total number (and percentage) of scats collected for the
zones was 465 (36.73%) for Zone 1 (the southern slope of the
land-bridge), 42 (3.32%) for Zone 2 (the top of the land-bridge)
and 759 (59.95%) for Zone 3 (the northern slope). There was a
significant difference (F = 33.10, d.f. = 2, 25, P < 0.0001) in the
mean weekly number of scats between each of Zones 1 (17.89 ±
1.94), 2 (1.62 ± 0.32) and 3 (29.19 ± 3.68), with Zone 3 having
significantly higher scat abundance and Zone 2 having the
lowest scat abundance.
Scats from seven different taxa were collected on the land-
bridge. Brown hare scats accounted for 76.1% of all scats col-
lected during the intensive surveys, with red-necked wallaby the
next most abundant (14.8%) (Table 3). Initially, macropods
dominated the number of scats collected. These began to
decrease noticeably after Week 11 as brown hare scats began to
increase (Fig. 5). Scats from eastern grey kangaroos, swamp
wallabies, possums, echidnas and feral carnivores were also col-
lected from the land-bridge but in much smaller numbers.
A two-week scat-sampling survey was conducted during
June 2007 and data compared with those for the equivalent
period in June 2006 (Table 4). This ‘snap-shot’ comparison
indicates that most of the dominant species present on the
land-bridge in 2006 were present a year later and that scats of
the macropod species were considerably more abundant in
2007. A more detailed comparison of these data (Table 4,
excluding ‘feral carnivores’ because of low numbers) revealed
significantly fewer red-necked wallabies and more of both
Table 4. Total numbers (and percentages) of scats of vertebrate taxa collected for all zones of the
land-bridge during two weekly surveys in winter 2006 and 2007
Taxa or category 2006 2007
Week 1 Week 2 Total (%) Week 1 Week 2 Total (%)
Red-necked wallaby 37 8 45 (46.3) 22 8 30 (19.2)
Swamp wallaby 0 7 7 (7.2) 30 8 38 (23.1)
Grey kangaroo 8 1 9 (8.0) 16 4 20 (12.7)
Brown hare 17 17 34 (35.0) 17 48 65 (41.6)
Introduced predator 2 0 2 (0.1) 2 1 3 (1.8)
Total 64 33 97 (100) 87 69 156 (100)

Use of fauna underpasses and overpasses Wildlife Research 109
Table 5. Animals detected as road-kill on Compton Road before construction (February–June 2004),
4 months after construction (February–June 2005) and times since (June 2005 to June 2007)
Preconstruction surveys were conducted on foot, postconstruction surveys were conducted from moving
vehicle only (see Methods for further details). Note: only species larger than blue-tongued skinks were
recorded after construction
Taxa Preconstruction Postconstruction Period from
(4 months) (4 months) 24 months
Red-necked wallaby 1 1 1
Swamp wallaby 1
Common ringtail possum 3 1
Northern brown bandicoot 1
Cat 1
Dog 1
Pheasant coucal, Centropus phasianus 1
Torresian crow, Corvus orru 1
Australian wood duck, Chenonetta jubata 1
Unidentified bird 1
Brown tree-snake, Boiga irregularis 1
Small-eyed snake, Cryptophis nigrescens 1
Carpet python, Morelia spilota 1
Total 13 2 3
swamp wallabies and grey kangaroos in 2007 (χ2 = 56.71, d.f.
= 4, P < 0.0001). Both brown hare and feral carnivore scats
were collected in similar numbers, the latter remaining rela-
tively rare.
Road-kill surveys
A total of 13 terrestrial vertebrates of 10 species were detected
as road-kill during the 4-month preconstruction survey
(Table 5). These included three common ringtail possums, two
macropods (red-necked wallaby and swamp wallaby), three
birds, two reptiles (both snakes) and a dog and a cat, both of
which were likely to have been roaming domestic animals rather
than feral animals. In the 4 months immediately following the
end of construction, despite the presence of the exclusion
fencing, two large animals were detected that had been killed on
the road. The single red-necked wallaby was able to reach the
road because of a large hole deliberately cut in the fence,
whereas the wood duck appears to have been hit while landing
on the road during the night. In the 29 months (to June 2007)
since the completion of construction, only a further three verte-
brates have been added to this list, including another red-necked
wallaby, again making use of breach due to vandals.
Given that postconstruction roadkill surveys were under-
taken from a travelling vehicle they are unlikely to have detected
all but the larger species, so no quantitative comparisons are
possible.
Discussion
The main aims of the present study were to assess use by
wildlife of the two underpasses and a land-bridge 6 months after
the opening of the structures, and over the longer term (two
years). The results demonstrated clearly that both structure
types were used quickly and regularly by a considerable diver-
sity of wildlife taxa, that some individuals of numerous species
made full crossings of the road by using the underpasses and
that use continued throughout the study.
Fauna presence in underpasses
Although numerous studies have shown that many species do
make use of underpasses, several workers have suggested that
regular use may not be well established for months or years (see
Hunt et al. 1987; Foster and Humphrey 1995; Clevenger and
Waltho 2005). Mata et al. (2005), for example, suggested that
even after four years animals may still be habituating to the
structure. The present study commenced within 6 months of the
completion of construction; large-scale physical disturbance of
the local environment was clearly evident, most of the plantings
remained small and the ends of the underpasses and the existing
forest remained distinctly separated. Moreover, while the length
of the underpasses was 48 m, the actual distance between the
bushland areas on either side was 58–65 m. Thus the remaining
physical disturbance and the distance between the forest edges
led us to expect little use of the underpasses by fauna so soon
after construction (see also Findlay and Bourdages 2000).
Nonetheless, we found clear evidence of vertebrate activity in
the underpasses from the start of the surveys and this continued
throughout the study. Similarly, Goosem et al. (2006) found that
while some species of small mammal used underpasses in trop-
ical rainforest almost immediately after construction, others had
not, even after several years.
The distinct increase in overall activity associated with
periods of the warmer seasons found in both years was due to
increases in small mammal activity and has been observed in
numerous international studies (Rodriguez et al. 1996;
McDonald and St Clair 2004; Ng et al. 2004; Goosem et al.
2006). Seasonality of animal movement and dispersal is well
documented, with the advent of breeding seasons and warmer
weather often accounting for increases in animal movement
(Bennett 1991; Law and Dickman 1998). The ‘rodent’ group,
house mouse and northern brown bandicoots, were all detected
in much greater numbers during December and January of the
intensive surveys but this pattern was not repeated the following

110 Wildlife Research A. R. Bond and D. N. Jones
year; the monthly surveys of 2006–07 revealed increases in
bandicoot numbers only (18 were detected in 24 h for January
2007). The low numbers of small mammals recorded in the
latter was almost certainly due to the continuation of the severe
drought conditions affecting the entire region throughout the
study period; concurrent trapping studies in the adjacent bush-
land similarly found extremely low numbers of all small
mammal species (Garden et al. 2007; D. Jones, unpubl. data).
The resilience of the bandicoots is, therefore, particularly note-
worthy (FitzGibbon and Jones 2006).
Both underpasses were visited by similar numbers of animals.
With few exceptions, most taxa were detected in both under-
passes and during both surveys. Small mammals, primarily
rodents, were by far the most frequent visitors to the under-
passes, although bandicoots comprised a significant proportion
of the total. Regular detection in underpasses of small mammals,
especially rodents, has been frequently reported in both
Australian (e.g. Abson and Lawrence 2003; Taylor and
Goldingay 2003; Goosem et al. 2006) and Northern Hemisphere
(Yanes et al. 1995; Rodriguez et al. 1997; McDonald and St Clair
2004; Ng et al. 2004) studies. Far less common are reports of
lizards in underpasses, the primary exceptions being Spanish
studies (Rodriguez et al. 1996; Mata et al. 2005). This taxon was
the second most abundant detected in the present study, although
few appeared to make crossings (Table 2).
A crucial goal of these surveys was an assessment of the
extent to which individuals of the different taxa were using the
underpasses to cross the road. Being almost 50 m in length,
movement through the entire length of the concrete structure
would constitute a substantial journey for a small animal.
Nonetheless, substantial numbers of individuals did make full
crossings: ~16% of all animals entering the underpasses each
day during the intensive surveys and ~30% during the monthly
surveys. The proportion of animals crossing was highly variable
among taxa but was greater for large species such as possums,
bandicoots and cats and dogs. On average, we estimated about
one animal made a crossing per night.
There has been considerable discussion on the optimal dimen-
sions and design of fauna-friendly crossing structures (Clevenger
and Waltho 2000, 2005; McDonald and St Clair 2004).
Numerous field studies have confirmed that different dimen-
sions appear to favour different taxa, with larger species much
more likely to use larger structures (Clevenger and Waltho 2005).
Although many purpose-built passages have been designed for
larger species (the Compton Road underpasses, for example,
were intentionally designed to be large enough to accommodate
a wallaby), several recent studies have found that small mammals
are much more likely to use smaller, enclosed passages (Mata et
al. 2005), even when these were relatively long (Rodriguez et al.
1997; cf.Yanes et al. 1995). McDonald and St Clair (2004) deter-
mined that small mammals preferred to move through passages
with more proximate cover, such as that provided by circular cul-
verts 0.3 m in diameter to larger (3 m) open passages. Other
studies have shown that proximity to cover at the ends of the pas-
sages is especially important (Rodriguez et al. 1997).
The present study also included an assessment of the use of
raised shelves. Many small mammals used these features, with
20% of ‘rodents’ and 40% of all dasyurids entering the under-
passes travelling above the floor.
Presence of fauna on the land-bridge
The construction of overpasses or land-bridges to facilitate
wildlife passage has been employed less often than have under-
passes (Magnus et al. 2004), but these structures have been used
by a range of typically larger mammalian species (Clevenger
and Waltho 2000; McDonald and St Clair 2004). Numerous
workers have argued that these large and obtrusive structures
may be actively avoided by many species (see Clevenger and
Waltho 2000, 2005). The aims of this part of the present study
were to determine whether wildlife visited the land-bridge and
to identify the species involved. We employed passive moni-
toring approaches (scat sampling) that addressed both aspects
but did not attempt to estimate the number of animals involved.
While scat-sampling techniques have been used to estimate
numbers of animals in other studies (e.g. Johnson et al. 1987;
Johnson and Jarman 1987), detailed information on species-
specific and location-specif ic defaecation rates and scat decay
rates would be required (Laing et al. 2003); such data are cur-
rently unavailable. Our data, therefore, relate to the abundance
of scats only and cannot be used to infer abundances of species
or individuals.
Patterns of faunal presence on the land-bridge were very dif-
ferent from those observed in the underpasses. Scat abundances
varied considerably over time and between surveys and included
numerous apparently low-activity periods (Fig. 5), reflecting
significant changes in the activity levels of the main animals
using the structure. At the start of the present study, large
numbers of scats of three macropod species and brown hares
were detected on the structure, although red-necked wallabies
were by far the most abundant macropod.
This unexpectedly rapid use of the structure (cf. Clevenger
and Waltho 2005; Mata et al. 2005) may have been associated
with the unintentional growth of weedy grasses germinating
from the mulch used to cover the entire structure. These grasses
may have been especially attractive since foraging resources
within the forests were probably very restricted due to the pro-
longed drought conditions at the time. The attraction of grazing
animals to the structure by the growth of these grasses may have
been important in the apparently rapid familiarity of the struc-
ture by these species and suggests that intentional seeding of the
land-bridge may be a valuable means of facilitating the process
of habituation (Clevenger and Waltho 2000) by target species.
The comparison of scats over equivalent two-week periods in
2006 and 2007 suggested that visits to the land-bridge had con-
tinued throughout the study period. Indeed, the proportion of
total macropod scats collected was significantly higher in 2007
than in the previous year. Again, this is almost certainly due to
the dramatic growth in plantings and grasses clearly evident
over the entire land-bridge. Given the impact of the drought on
the vegetation of the surrounding bushland, the continued
growth of fresh plants probably provided a valuable foraging
resource for local herbivorous species.
Effectiveness of exclusion fencing
Although of short duration, the preconstruction survey of road-
kill did provide valuable quantitative data on rates of road-kill
and, with a contemporaneous study of road impacts within the
same region (Buchanan 2005), confirmed that possums and wal-

Use of fauna underpasses and overpasses Wildlife Research 111
labies were the most common large vertebrates being killed on
local roads. The effectiveness of the fencing was demonstrated
partially by the clear reduction on reported fatalities of larger
species. Comparing the raw data from the 4-month period before
and after the completion of construction showed a reduction
from 13 to two large animals killed, and only a further two over
the entire 29 month postconstruction period. Obviously, smaller
species may have been killed but not detected.
It is also noteworthy that the only wallaby fatalities occurring
during this period were associated directly with human-induced
breaches in the fence. Clearly, continuous monitoring of the
fence is crucial for the fence to function as an effective barrier;
the exploitation of breaches in the fence occurred soon after they
appeared (both wallabies were killed within 12 h of the breaches
being noticed). In combination with easily accessed safe pas-
sages under and over the road, fences are an essential component
of the obvious success of the Compton Road structures.
Management implications
This study, using simple yet effective non-invasive monitoring
approaches, has demonstrated clearly that a wide range of
species visited the fauna-friendly road-crossing structures at
Compton Road, and that this began soon after construction and
continued thereafter. In contrast to suggestions of lengthy
periods of adaptation and habituation for Northern Hemisphere
species, our findings indicated relatively early use of both
underpasses and overpasses followed by regular use, strongly
suggesting rapid habituation. Nonetheless, the sand-tracking
method employed was unable to reliably distinguish among
several important taxa, thereby limiting the clarity of the find-
ings. For example, while large numbers of the ‘rodents’category
used the underpasses early, we are unable to determine which
species were involved. In an important study from North
Queensland, Goosem et al. (2006) found early use by some
species while others appear to avoid the structures entirely for
years. A critical improvement of methods used here should
involve the reliable identif ication of species, especially by the
use of remote cameras (see Goosem 2005).
These surveys confirmed that a wide range of small and
medium-sized mammal species were the dominant visitors to
the underpasses. As numerous studies (Rodriguez et al. 1996;
McDonald and St Clair 2004; Ng et al. 2004; Mata et al. 2005)
have found that these taxa prefer smaller structures with denser,
more proximate cover, use of the relatively large underpasses
could almost certainly be enhanced by the inclusion of small-
mammal-specific ‘furniture’ such as hollow logs and pipes
along the open floor of the underpass. Furthermore, the consid-
erable use made of the raised shelves indicates that such features
could be incorporated into existing culverts and underpasses as
a means of encouraging increased use by small species.
The remarkably rapid and continuing presence on the land-
bridge of each of three species of macropod is likely due to the
provision of an attractive foraging resource on the structure
itself. While the growth of grasses in the landscaping mulch was
an unintended event, it appears to have been highly influential in
attracting these animals onto the structure and possibly advanc-
ing the process of habituation. The ongoing growth of plants has
apparently continued to attract these and other species over
several years. We would therefore advocate intentional planting
of appropriate vegetation as a means of facilitating habituation
by herbivorous species to such overpasses.
Acknowledgements
This project and the Compton Road Fauna Ar ray would not exist but for the
extraordinary efforts of many people but none more critical than Mary
O’Hare (Brisbane City Council) and Thomas Creevy (Karawatha Protection
Society). We sincerely thank Kristy Buchanan, Leigh Slater and Stacey
McLean of Brisbane City Council for their support. Thanks are also due to
Brendan Taylor for ongoing discussions and to Raymonde de Lathouder for
assistance in the field. We also acknowledge the valuable suggestions of
Camilla Myers, Andrea Taylor and two anonymous referees of an earlier
draft of this paper.
References
Aars, J., and Ims, R. A. (1999). The effect of habitat corridors on rates of
transfer and interbreeding between vole demes. Ecology 80, 1648–1675.
Abson, R. N., and Lawrence, R. E. (2003). Monitoring the use of the Slaty
Creek wildlife underpass, Calder Freeway, Black Forest, Macedon,
Victoria, Australia. In ‘Proceedings of International Conference of
Ecology and Transportation 2003’. (Eds C. L. Irwin, P. Garrett and
K. P. McDermott.) pp. 303–308. (Centre for Transportation and the
Environment, North Carolina State University: Raleigh, USA.)
Anon, (2006). Crossings for all creatures? Courier Mail, Brisbane
25(April), 60.
Bennett, A. F. (1991). Roads, roadsides and wildlife conservation: a review.
In ‘Nature Conservation 2: The Role of Corridors’. (Eds D. A. Saunders
and R. J. Hobbs.) pp. 99–117. (Surrey Beatty: Sydney.)
Buchanan, K. (2005). Sharing the way with wildlife: macropod mortality on
roads in Redland Bay. M.Sc. Thesis, Griffith University, Brisbane.
Chenoweth, E. (2003). Ecological Corridors and Edge Effects Project: Case
Study – Greenbank–Karawatha Corridor. Chenoweth Environmental
Planning and Landscape Architecture, Brisbane.
Clevenger, A. P., and Waltho, N. (2000). Factors affecting the effectiveness
of wildlife underpasses in Banff National Park, Alberta, Canada.
Conservation Biology 14, 47–56. doi:10.1046/j.1523-1739.2000.
00099-085.x
Clevenger, A. P., and Waltho, N. (2005). Performance indices to identify
attributes of highway crossing structures facilitating movements of large
mammals. Biological Conservation 121, 453–464. doi:10.1016/
j.biocon.2004.04.025
Clevenger, A. P., Chruszcz, B., and Gunson, K. E. (2001). Highway mitiga-
tion fencing reduces wildlife–vehicle collisions. Wildlife Society
Bulletin 29, 646–653.
Findlay, S. C., and Bourdages, J. (2000). Response time of wetland bio-
diversity to road construction on adjacent lands. Conservation Biology
14, 86–94. doi:10.1046/j.1523-1739.2000.99086.x
FitzGibbon, S. I., and Jones, D. N. (2006). A community-based wildlife
survey: the knowledge and attitudes of residents of suburban Brisbane,
with a focus on bandicoots. Wildlife Research 33, 233–241.
doi:10.1071/WR04029
Forman, R. T. T., Sperling, D., Bissonette, J. A., Clevenger, A. P., Cutshall,
C. D., et al. (2003). ‘Road Ecology: Science and Solutions.’ (Island
Press: Washington.)
Foster, M. L., and Humphrey, S. R. (1995). Use of underpasses by Florida
panthers and other wildlife. Wildlife Society Bulletin 23, 95–100.
Garden, J. G., McAlpine, C. A., Possingham, H. P., and Jones, D. N. (2007).
Using multiple survey methods to detect terrestrial reptiles and
mammals: what are the most successful and cost-efficient combina-
tions? Wildlife Research 34, 218–227.
Goosem, M. (2001). Effects of tropical rainforest roads on small mammals:
inhibition of crossing movements. Wildlife Research 28, 351–364.
doi:10.1071/WR99093

112 Wildlife Research
Goosem, M. W. (2005). Wildlife surveillance assessment. Compton Road
upgrade 2005: review of contemporary remote and direct surveillance
options for monitoring. Report to the Brisbane City Council.
Cooperative Research Centre for Tropical Rainforest Ecology and
Management, Cairns.
Goosem, M., Izumi, Y., and Turton, S. (2001). Efforts to restore habitat con-
nectivity for an upland tropical rainforest fauna: a trial of underpasses
below roads. Ecological Management & Restoration 2, 196–202.
doi:10.1046/j.1442-8903.2001.00084.x
Goosem, M., Weston, Y., and Bushnell, S. (2006). Effectiveness of rope
bridge arboreal overpasses and faunal underpasses in providing connec-
tivity for rainforest fauna. In ‘Proceedings of International Conference
of Ecology and Transportation 2005’. (Eds C. L. Irwin, P. Garrett and
K. P. McDermott.) pp. 304–316. (Centre for Transportation and the
Environment, North Carolina State University: Raleigh, USA.)
Hunt, A., Dickens, N., and Whelan, R. J. (1987). Movement of mammals
through tunnels under railway lines. Australian Zoologist 24, 89–93.
Johnson, C. N., and Jarman, P. J. (1987). Macropod studies at Wallaby
Creek. VI. A validation of the use of dung-pellet counts for measuring
absolute densities of populations of macropodids. Australian Wildlife
Research 14, 139–145. doi:10.1071/WR9870139
Johnson, C. N., Jarman, P. J., and Southwell, C. J. (1987). Macropod studies
at Wallaby Creek. V. Patterns of defecation by eastern grey kangaroos
and red-necked wallabies. Australian Wildlife Research 14, 133–138.
doi:10.1071/WR9870133
Jones, M. E. (2000). Road upgrade, road mortality and remedial measures:
impacts on a population of eastern quolls and Tasmanian devils. Wildlife
Research 27, 289–296. doi:10.1071/WR98069
Kehl, J., and Corben, C. (1991). The fauna of Karawatha: preliminary study.
Brisbane City Council, Brisbane.
Kordas, K., Coutts, R. H., and Catterall, C. P. (1993). The vegetation of
Karawatha Forest and its signif icance in the south-east Queensland
landscape. Karawatha Forest Protection Society, Brisbane.
Laing, S. E., Buckland, S. T., Burn, R. W., Lambie, D., and Amphlett, A.
(2003). Dung and nest surveys: estimating decay rates. Journal of
Applied Ecology 40, 1102–1111. doi:10.1111/j.1365-2664.2003.
00861.x
Law, B. S., and Dickman, C. R. (1998). The use of habitat mosaics by
terrestrial vertebrate fauna: implications for conservation and manage-
ment. Biodiversity and Conservation 7, 323–333. doi:10.1023/
A:1008877611726
Mack, P. (2005). When fauna corridors and arterial road corridors intersect.
City Design, Brisbane City Council.
Magnus, Z., Kriwoken, L., Mooney, N., and Jones, M. (2004). Reducing the
incidence of wildlife roadkill: improving the visitor experience in
Tasmania. CRC Tourism Research Report, CRC Sustainable Tourism,
Southport.
Mansergh, I. M., and Scotts, D. J. (1989). Habitat continuity and social orga-
nization of the mountain pygmy-possum restored by tunnel. Journal of
Wildlife Management 53, 701–707. doi:10.2307/3809200
Mata, C., Hervas, I., Herranz, J., Suarez, F., and Malo, J. E. (2005).
Complementary use by vertebrates of crossing structures along a fenced
Spanish motorway. Biological Conservation 124, 397–405.
doi:10.1016/j.biocon.2005.01.044
A. R. Bond and D. N. Jones
McDonald, W., and St Clair, C. C. (2004). Elements that promote highway
crossing structure use by small mammals in Banff National Park.
Journal of Applied Ecology 41, 82–93. doi:10.1111/j.1365-2664.2004.
00877.x
Menkhorst, P., and Knight, F. (2004). ‘A Field Guide to the Mammals of
Australia.’ 2nd edn. (Oxford University Press: Melbourne.)
Morrison, R. G. B. (1981). ‘A Field Guide to the Tracks and Traces of
Australian Animals.’ (Rigby Publishers Limited: Australia.)
Ng, S. J., Dole, J. W., Sauvajot, R. M., Riley, S. P. D., and Valone, T. J. (2004).
Use of highway undercrossings by wildlife in southern California.
Biological Conservation 115, 499–507. doi:10.1016/S0006-3207(03)
00166-6
Oxley, D. J., Fenton, M. B., and Carmody, G. R. (1974). The effects of roads
on populations of small mammals. Journal of Applied Ecology 11,
51–59. doi:10.2307/2402004
Rodriguez, A., Crema, G., and Delibes, M. (1996). Use of non-wildlife pas-
sages across a high speed railway by terrestrial vertebrates. Journal of
Applied Ecology 33, 1527–1540. doi:10.2307/2404791
Rodriguez, A., Crema, G., and Delibes, M. (1997). Factors affecting cross-
ing of red foxes and wildcats through non-wildlife passages across a
high-speed railway. Ecography 20, 287–294. doi:10.1111/j.1600-
0587.1997.tb00373.x
Stewart, D. (1997). The vertebrate fauna of land adjacent to Karawatha
Reserve. Report for the Karawatha Forest Protection Society.
Taylor, B. D., and Goldingay, R. L. (2003). Cutting the carnage: wildlife
usage of road culverts in north-eastern New South Wales. Wildlife
Research 30, 529–537. doi:10.1071/WR01062
Taylor, B. D., and Goldingay, R. L. (2004). Wildlife road-kills on three major
roads in north-eastern New South Wales. Wildlife Research 31, 83–91.
doi:10.1071/WR01110
Triggs, B. (2004). ‘Tracks, Scats and other Traces: a Field Guide to
Australian Mammals.’ Rev. edn. (Oxford University Press: Melbourne.)
van der Ree, R., van der Grift, E., and Mata, C. (2007). Overcoming the
barrier effects of roads – how effective are mitigation strategies?
(Abstract) In ‘2007 International Conference on Ecology and
Transportation, Little Rock, Arkansas, USA, 20–25 May 2007’.
www.icoet.net/ICOET_2007/abstracts/07abstract1.asp#2
Veage, L., and Jones, D. N. (2007). Breaking the barrier: assessing the value
of fauna-friendly crossing structures at Compton Road. Report to
Brisbane City Council, Centre for Innovative Conservation Strategies,
Griffith University.
Yanes, M., Velasco, J. M., and Sufirez, F. (1995). Permeability of roads and
railways to vertebrates: the importance of culverts. Biological
Conservation 71, 217–222. doi:10.1016/0006-3207(94)00028-O
Manuscript received 5 March 2007, accepted 11 March 2008
http://www.publish.csiro.au/journals/wr