The conservation of mammals in Victoria's roadsides

Abstract

There’s nothing quite like a scenic drive along a tree-lined highway. Majestic eucalypts stand sentry like a guard of honour. As passengers gazing out the car window, we might not think of these narrow, highway-side reserves as prime habitat for wildlife. Yet in many landscapes across Victoria, ‘roadside reserves’ are all that remains of the pre-European woodland vegetation. This poses the question: If the only habitat left occurs along roadsides, what does this mean for wildlife? I discussed this issue at the Mammals of Victoria seminar hosted by the Field Naturalists Club of Victoria in March 2015, with particular reference to woodland mammals. © 2016, Field Naturalists Club of Victoria. All rights reserved.

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This%is%a%pre-published%version.%For%the%final%manuscript,%please%see The Victorian 1!
Naturalist 133(3) 2016, 79–84%2!
The$conservation$of$mammals$in$Victoria’s$roadsides$3!
!4!
Kylie!Soanes!5!
ksoanes@unimelb.edu.au!6!
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[Main!text]!8!
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There's!nothing!quite!like!a!scenic!drive!along!a!tree-lined!highway.!Majestic!eucalypts!10!
stand!sentry!like!a!guard!of!honour.!As!passengers!gazing!out!the!car!window,!we!might!not!11!
think!of!these!narrow,!highway-side!reserves!as!prime!habitat!for!wildlife.!Yet!in!many!12!
landscapes!across!Victoria,!‘roadside!reserves’!are!all!that!remains!of!the!pre-European!13!
woodland!vegetation.!This!begs!the!question:!If!the!only!habitat!left!occurs!along!roadsides,!14!
what!does!this!mean!for!wildlife?!I!discussed!this!issue!at!the!!"##"$%&'(&)*+,'-*"!seminar!15!
hosted!by!the!Field!Naturalist!Club!of!Victoria!in!March!2015,!with!particular!reference!to!16!
woodland!mammals.!!17!
!18!
Victoria’s$roadside$woodlands$19!
To!put!it!into!perspective,!in!Victoria!we!have!156,000!km!of!road!travelled!by!more!20!
than!4!million!registered!vehicles!(AustRoads!2003;!Australian!Bureau!of!Statistics).!The!21!
resulting!satellite!imagery!is!striking!(Figure!1).!Most!of!Victoria’s!land!is!within!1!km!of!the!22!
nearest!road,!meaning!that!in!the!vast!majority!of!landscapes,!wildlife!are!living!in!roadside!23!
vegetation!or!road-affected!habitats.!In!fact,!in!many!areas!roadside!vegetation!may!be!the!only!24!
suitable!habitat!that!is!left.!For!example,!within!highly-modified!landscapes!(e.g.!agricultural!or!25!
semi-urban!landscapes),!mature!Eucalyptus!woodland!is!almost!entirely!restricted!to!linear!26!
strips!along!roadsides,!paddock!edges!and!waterways!(Figure!2).!Species!that!depend!on!27!
woodland!habitats!are,!therefore,!largely!restricted!to!living!near!roads!(Suckling!1984;!Bennett!28!
1988;!Gilbert!1998;!van!der!Ree!and!Bennett!2003).!Roadsides!can!represent!high-quality!29!
habitat!for!woodland!mammals!because!they!often!host!a!high!density!of!large,!old,!hollow-30!
bearing!trees!–!a!critical!resource!for!woodland!fauna,!including!threatened!species!such!as!the!31!
Brush-tailed!Phascogale!./%"+'0"$1&,"2'","("&and!Squirrel!Glider!.1,"3-3%&4'-('$+14%*%5!32!
Furthermore,!just!as!the!road!network!provides!connectivity!for!people,!the!network!of!33!
roadside!habitats!provides!connectivity!for!woodland!wildlife,!allowing!them!to!move!through!34!
otherwise!fragmented!landscapes!(e.g.!Suckling!1984;!Bennett!1990;!Downes!1,&"$5!1997).!The!35!

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ability!to!manage!the!negative!impacts!of!roads!on!wildlife!is,!therefore,!a!critical!component!of!36!
conservation!efforts!for!many!threatened!species.!37!
The$danger$zone$38!
Living!in!roadsides!presents!several!challenges!to!wildlife,!and!thus!to!the!managers!39!
wishing!to!conserve!them.!There!are!many!ecological!impacts!that!can!make!roadside!habitats!40!
unsuitable!for!some!species!(Forman&1,&"$5!2003;!Donaldson!and!Bennett!2004;!van!der!Ree&1,&41!
"$5!2015).!For!example,!edge!effects,!dust,!noise!and!light!pollution!can!displace!the!more!42!
sensitive!species!(e.g.!Eigenbrod&1,&"$5!2009;!Parris!and!Schneider!2009).!However,!here!I!focus!43!
on!two!main!impacts!of!roads!on!species!that!live!within!roadside!habitats:!the!mortality!(road!44!
kill)!and!barrier!effects.!!45!
The!most!obvious,!and!distressing,!impact!is!roadkill.!Common!mammal!victims!on!46!
Australian!roads!include!kangaroos,!wallabies,!wombats,!echidna,!koalas,!bandicoots!and!47!
possums!(e.g.!Coulson!1982,!1997;!Dique&1,&"$5!2003;!Taylor!and!Goldingay!2004;!Russell&1,&"$5!48!
2009;!Bond!and!Jones!2014).!McCall!1,&"$5&(2010)!showed!that!the!survival!rate!of!Squirrel!49!
Gliders!living!adjacent!to!the!Hume!Freeway!was!approximately!60%!lower!than!populations!50!
living!more!than!5!km!away.!Roadkill!has!also!been!implicated!in!the!population!decline!of!the!51!
Swamp!Wallaby!6"$$"7*"&7*+'$'-!in!Royal!National!Park,!NSW!(Ramp!and!Ben-Ami!2006),!and!52!
the!Eastern!Quoll!8"%93-3%&:*:1--*43%,!and!Tasmanian!Devil!;"-+'2/*$3%&/"--*%**!after!a!road!53!
upgrade!in!Tasmania!(Jones!2000).!!54!
Roads!also!create!barriers!to!movement,!restricting!access!to!resources!and!reducing!55!
dispersal!and!gene!flow!(Shepard&1,&"$5!2008;!Holderegger!and!Di!Giulio!2010).!Arboreal!56!
mammals!are!particularly!vulnerable!to!the!barrier!effect!of!roads,!with!larger!roads!such!as!the!57!
Hume!Freeway!and!Goulburn!Valley!Highway!proven!to!restrict!the!movement!of!Common!58!
Brushtail!Possums!(Gulle!2006)!and!Squirrel!Gliders!(van!der!Ree!2006;!van!der!Ree&1,&"$5!59!
2010).!Studies!from!Queensland!show!that!even!narrow!roads!can!be!barriers!for!smaller!60!
mammal!species!(e.g.!Burnett!1992;!Goosem!2001).!!Ultimately!a!road!can!be!a!tipping!point!in!61!
already!vulnerable!populations,!where!the!loss!of!even!a!few!individuals!through!roadkill,!or!the!62!
creation!of!barriers!that!restrict!gene!flow!and!access!to!patchy!resources!can!lead!to!rapid!63!
population!declines!(Bennett!1991;!Forman!1,&"$5!2003;!Coffin!2007).!!64!
Managing$the$risks$to$wildlife$65!
Given!the!extent!of!land!already!affected!by!roads,!we!need!methods!that!effectively!66!
mitigate!their!negative!effects!on!wildlife.!Wildlife!fencing!can!reduce!rates!of!roadkill!by!67!
keeping!animals!off!the!road.!However!fences!can!make!the!'barrier!effect'!of!roads!worse!by!68!
further!restricting!animal!movements,!and!are!detrimental!when!species!persistence!depends!69!
on!movement!among!multiple!patches!of!habitat!(Jaeger!and!Fahrig!2004).!Wildlife!crossing!70!
structures!can!allow!safe!passage!across!roads!to!improve!habitat!connectivity,!and,!when!used!71!

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in!conjunction!with!fencing,!they!can!simultaneously!reduce!roadkill.!There!are!many!different!72!
types!of!crossing!structures,!but!they!generally!fall!into!two!categories:!those!that!allow!animals!73!
to!move!over!the!road!(e.g.!rope!bridges,!land!bridges,!overpasses),!and!those!that!allow!animals!74!
to!move!under!the!road!(e.g.!culverts,!tunnels,!creek-crossings).!While!crossing!structures!are!75!
more!common!in!Europe!and!North!America!(van!der!Ree&1,&"$5!2007,!van!der!Ree!1,&"$5!2008),!76!
road!agencies!in!Australia!are!increasingly!including!crossing!structures!in!road!projects!(e.g.!77!
Taylor!and!Goldingay!2003;!Bond!and!Jones!2008;!Goldingay&1,&"$5!2013).!In!Victoria,!wildlife!78!
crossing!structures!have!predominantly!been!constructed!on!major!roads!such!as!the!Hume!79!
Freeway,!Calder!Freeway,!Princes!Highway!and!Peninsula!Link!(Abson!and!Lawrence!2003;!van!80!
der!Ree!1,&"$5!2008;!Soanes&1,&"$5!2013;!Soanes&1,&"$5!2015).!!81!
One!of!the!most!famous!structures!in!Victoria!is!the!aptly-named!'Tunnel!of!Love',!at!the!82!
Mount!Hotham!Ski!Resort.!A!long-term!population!study!of!the!critically!endangered!Mountain!83!
Pygmy!Possum!<3--"#9%&2"-:3%=!revealed!that!the!Great!Alpine!Road!bisected!important!84!
habitat!patches!(Mansergh!and!Scotts!1989).!This!barrier!disrupted!the!social!organisation!of!85!
the!local!population,!restricting!dispersal!in!males!and!reducing!over-winter!survival!in!females.!86!
Two!tunnels!(0.9!x!1.2!m!cross!section)!were!constructed!in!1985!through!the!rock!scree!under!87!
the!road!in!1985!to!restore!connectivity.!Ongoing!research!showed!that!Mountain!Pygmy!88!
Possums!used!the!tunnels,!and!that!dispersal!and!over-winter!survival!rates!recovered!89!
(Mansergh!and!Scotts!1989).!This!information!was!later!used!in!a!population!viability!analysis,!90!
which!suggested!that!while!the!crossing!structure!improved!the!viability!of!the!Mountain!Pygmy!91!
Possum,!the!negative!effect!of!the!road!may!have!been!only!partially!mitigated!(van!der!Ree&1,&92!
"$5!2009).!!93!
Larger!underpasses!can!cater!for!a!wide!variety!of!species.!When!the!Black!Forest!94!
section!of!the!Calder!Freeway!was!upgraded!in!1997,!VicRoads!included!a!large!wildlife!95!
underpass!to!provide!connectivity!between!forest!patches!that!were!bisected!by!the!road.!The!96!
open-span!bridge!was!built!as!an!extended!creek!crossing,!long!enough!to!allow!both!the!creek!97!
and!the!surrounding!riparian!vegetation!to!pass!under!the!road.!The!structure!was!monitored!98!
five!years!after!it!was!built,!and!researchers!detected!several!mammal!species!using!the!99!
underpass!including!microbats,!koalas,!wombats,!echidna,!possums,!gliders!and!macropods!100!
(Abson!and!Lawrence!2003).!A!recent!review!showed!that!these!open-span!bridges!are!an!101!
effective!way!to!maintain!connectivity!across!roads!for!multiple!species!(Lesbarreres!and!Fahrig!102!
2012).!!103!
Aerial!crossing!structures,!rope!bridges!and!glider!poles,!were!used!to!reduce!the!impact!104!
of!the!Hume!Freeway!in!north-east!Victoria!on!arboreal!mammals.!A!before-after!research!105!
project!was!established!to!test!their!effectiveness,!focusing!on!the!ability!to!restore!movement!106!
and!gene!flow!in!Squirrel!Glider!populations.!Initial!studies!set!out!to!measure!the!effect!of!the!107!

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four-lane!divided!highway!on!Squirrel!Gliders!before!crossing!structures!were!installed.!108!
Researchers!found!that!where!the!gap!across!the!freeway!was!wider!than!50!m,!Squirrel!Gliders!109!
were!largely!unable!to!cross;!however,!where!tall!trees!had!been!left!in!the!roadsides!and!centre!110!
medians!(referred!to!as!‘vegetated!medians’),!the!animals!could!cross!freely!(van!der!Ree!1,&"$5&111!
2010).!Rope!bridges!and!glider!poles!were!then!retrofitted!to!the!freeway!in!July!2007!at!five!112!
sites!where!the!barrier!effect!occurred!(Figure!3).!Motion-triggered!cameras!detected!five!113!
species!of!arboreal!mammal!using!the!structures!to!cross!the!freeway,!including!the!Squirrel!114!
Glider,!Sugar!Glider,!Brush-tailed!Phascogale,!Common!Brushtail!Possum!and!Common!Ringtail!115!
Possum!(Soanes&1,&"$5!2013;!Soanes&1,&"$5!2015).!Further!radiotracking!and!genetic!research!was!116!
conducted!after!the!crossing!structures!were!installed,!and!revealed!that!rope!bridges,!glider!117!
poles!and!vegetated!medians!all!facilitated!movement!and!gene!flow!across!the!Hume!Freeway!118!
and!that!this!would!not!have!occurred!had!crossing!structures!not!been!present!(Soanes!2014).!119!
There!are!other!methods!to!reduce!the!effects!of!roads!on!wildlife,!such!as!those!120!
designed!to!alter!driver!behaviour!(e.g.!warning!signs),!or!repel!animals!from!the!road!(e.g.!121!
reflectors!or!ultrasonic!warnings).!Unfortunately!the!research!to-date!shows!that!these!are!122!
largely!unsuccessful!(Bender!2003;!Ramp!and!Croft!2006;!Bond!and!Jones!2014).!Methods!that!123!
force!drivers!to!slow!down!(e.g.!reduced!speed!limits,!pinch!points!and!rumble!strips)!have!been!124!
shown!to!be!effective!at!reducing!roadkill!in!'hot!spots'!(Jones!2000),!but!can!be!difficult!(and!125!
unpopular)!to!implement!over!large!areas.!A!potentially!promising!method!is!an!automatic-126!
warning!system,!designed!with!flashing!lights!that!warn!drivers!only!when!an!animal!is!127!
approaching!the!road!(Huijser!and!McGowan!2003;!Bond!and!Jones!2014).!128!
Opportunities$and$challenges$for$research$and$conservation$in$Victoria$129!
The!importance!of!managing!wildlife!in!linear!habitats!along!roads,!railways!and!other!130!
infrastructure!is!increasingly!being!recognised!in!Australia!and!worldwide!(Gilbert!1998;!131!
Carthew!1,&"$5!2013;!van!der!Ree&1,&"$5!2015).!Mammals!are!not!the!only!species!to!benefit!from!132!
roadside!habitats.!Roadside!vegetation!provides!critical!habitat!for!woodland!birds!(e.g.!133!
Robinson!2006),!reptiles!(e.g.!Brown!1,&"$5!2008;!Jellinek!1,&"$.!2014)!and!insects!(e.g.!Major!1,&134!
"$.!1999).!Victorian!roads!therefore!represent!a!great!opportunity!for!the!conservation!of!native!135!
mammals!and!other!fauna.!!136!
The!conservation!value!of!roadsides!will!depend!on!our!ability!to!manage!potential!137!
conflicts.!The!safety!risk!posed!to!drivers,!risk!of!bushfire!and!spread!of!invasive!species!are!all!138!
serious!issues!that!must!be!considered,!but!ones!that!can!be!controlled!through!appropriate!139!
management,!such!as!barrier!fencing!and!weed!control!(Gilbert!1998).!Roadside!habitats!are!140!
also!vulnerable!to!being!incrementally!chipped!away!as!roads!are!upgraded!to!accommodate!141!
higher!traffic!volumes.!For!example,!during!the!last!50!years,!rural!highways!such!as!the!Hume,!142!
Western!and!Calder!have!been!progressively!widened!to!create!four-lane!freeways.!However,!143!

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road!upgrades!do!not!necessarily!have!to!lead!to!the!loss!of!roadside!vegetation.!!144!
Environmentally-sensitive!road!designs,!such!as!the!creation!of!wide!medians!to!retain!145!
woodland!vegetation!and!alignment!of!road!corridors!to!avoid!remnant!patches,!can!help!146!
minimise!vegetation!loss,!and!are!particularly!important!in!landscapes!that!are!otherwise!147!
devoid!of!natural!vegetation.!Without!formal!protection!and!considered!planning!the!extent!and!148!
quality!of!roadside!habitats!for!wildlife!can!rapidly!decline.!!149!
Wildlife!crossing!structures!are!a!promising!tool!for!managing!the!negative!impacts!of!150!
roads,!not!only!for!woodland!mammals!but!also!for!a!range!of!other!wildlife!(van!der!Ree&1,&"$5!151!
2007;!van!der!Ree&1,&"$5!2015).!However,!a!practical!challenge!to!increasing!the!number!of!152!
wildlife!crossing!structures!in!Victoria!is!that!it!would!require!retrofitting!structures!to!existing!153!
roads,!a!process!that!can!be!difficult,!disruptive!and!costly.!One!option!is!to!take!the!opportunity!154!
to!include!wildlife!crossing!structures!and!other!mitigation!measures!in!future!road!upgrades,!155!
thus!minimising!the!cost!and!disruption.!Another!possibility!is!to!modify!existing!structures!that!156!
were!not!specifically!designed!for!wildlife,!such!as!drainage!culverts!and!pipes.!For!example,!157!
adding!guide!fencing,!small!ledges!and!‘fauna!furniture’!to!culverts!can!encourage!their!use!by!158!
fauna!while!maintaining!water!flows!(e.g.!Brudin!2003;!Foresman!2003).!159!
There!are!clear!opportunities!for!further!road!ecology!research!in!Victoria.!For!instance,!160!
there!are!surprisingly!few!published!studies!of!roadkill!on!Victorian!roads!(although!I!suspect!161!
that!many!useful!datasets!are!hidden!within!the!‘grey!literature’).!Research!that!combines!data!162!
from!roadkill!studies,!insurance!reports!and!wildlife!rescue!groups!would!help!provide!a!better!163!
understanding!of!the!extent!of!the!roadkill!problem!in!Victoria.!For!example,!identifying!164!
hotspots,!the!relative!risk!for!each!species,!and!the!degree!to!which!roadkill!depletes!the!165!
surrounding!population!are!important!gaps!in!the!current!knowledge.!There!is!still!work!to!be!166!
done!to!quantify!the!value!of!roadside!habitats!to!wildlife!populations.!Studies!that!assess!the!167!
ability!of!wildlife!populations!to!persist!in!roadside!habitats!are!needed!to!guide!effective!168!
management!and!mitigation.!Can!a!network!of!roadside!reserves!support!viable!populations!in!169!
the!long-term?!Do!species!use!roadsides!as!permanent!habitats!(home!range),!supplementary!170!
resources!(feeding!on!grasses!etc.),!or!simply!as!movement!corridors?!Finally,!we!need!more!171!
studies!that!test!the!effectiveness!of!mitigation!measures!such!as!wildlife!crossing!structures.!172!
While!it!is!evident!that!animals!will!use!these!structures,!the!next!step!is!to!determine!whether!173!
they!improve!the!population!persistence!within!a!landscape!(van!der!Grift!1,&"$5&2013).!Only!174!
through!careful!research!and!management!will!we!be!able!maximise!the!value!of!roadside!175!
habitats!for!wildlife,!and!continue!to!enjoy!our!scenic!woodland!drives.!!176!
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Abson!R!and!Lawrence!RE!(2003)!Monitoring!the!use!of!the!Slaty!Creek!wildlife!underpass,!182!
Calder!Freeway,!Black!Forest,!Macedon,!Victoria,!Australia.!In:!.-'+11>*40%&'(&,/1&?4,1-4",*'4"$&183!
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Australian!Bureau!of!Statistics.!Motor!vehicle!census.!Accessed!23/8/2015!188!
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Bender!H!(2003)!Deterrence!of!kangaroos!from!agricultural!areas!using!ultrasonic!frequencies:!194!
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Bennett!AF!(1988)!Roadside!vegetation:!a!habitat!for!mammals!at!Naringal,!south-200!
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Surrey!Beatty!and!Sons.!205!
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Bond!AR!and!Jones!DN!(2008)!Temporal!trends!in!use!of!fauna-friendly!underpasses!and!207!
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fragmented!rural!landscapes!of!south-eastern!Australia.!6*$>$*(1&C1%1"-+/!35,!8–18.!214!
!215!
Brudin!CO!(2003)!Wildlife!use!of!existing!culverts!and!bridges!in!north!central!Pennsylvania.!In:!216!
.-'+11>*40%&'(&,/1&?4,1-4",*'4"$&@'4(1-14+1&'4&A+'$'09&"4>&B-"4%2'-,",*'4!(Eds!C!L!Irwin,!D!217!
Nelson,!and!K!P!McDermott)!pp!344–352!(Center!for!Transportation!and!The!Environment,!218!
North!Carolina!State!University,!Raleigh,!NC).!219!
!220!
Burnett!SE!(1992)!Effects!of!a!rainforest!road!on!movements!of!small!mammals:!mechanisms!221!
and!implications.!6*$>$*(1&C1%1"-+/!19,!95–104.!222!
!223!
Carthew!SM,!Garrett!LA!and!Ruykys!L!(2013)!Roadside!vegetation!can!provide!valuable!habitat!224!
for!small,!terrestrial!fauna!in!South!Australia.!<*'>*:1-%*,9&"4>&@'4%1-:",*'4!22,!737–754.!225!
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Coffin!AW!(2007)!From!roadkill!to!road!ecology:!A!review!of!the!ecological!effects!of!roads.!227!
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Coulson!GM!(1982)!Road-kills!of!macropods!on!a!section!of!highway!in!central!Victoria.!230!
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7!
!233!
Coulson!G!(1997)!Male!bias!in!road-kills!of!macropods.!6*$>$*(1&C1%1"-+/!24,!21–25.!234!
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Dique!DS,!Thompson!J,!Preece!HJ,!Penfold!GC,!de!Villiers!DL!and!Leslie!RS!(2003)!Koala!236!
mortality!on!roads!in!south-east!Queensland:!the!koala!speed-zone!trial.!6*$>$*(1&C1%1"-+/!30,!237!
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Donaldson!A!and!Bennett!AF!(2004)!A+'$'0*+"$&1((1+,%&'(&-'">%&&?#2$*+",*'4%&('-&,/1&*4,1-4"$&240!
(-"0#14,",*'4&'(&N3%,-"$*"4&."-Q%&"4>&-1%1-:1%.!(Parks!Victoria:!Melbourne).!241!
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Downes!SJ,!Handasyde!KA!and!Elgar!MA!(1997)!The!use!of!corridors!by!mammals!in!fragmented!243!
Australian!eucalypt!forests.!@'4%1-:",*'4&<*'$'09!11,!718–726.!244!
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Eigenbrod!F,!Hecnar!SJ!and!Fahrig!L!(2009)!Quantifying!the!road-effect!zone:!Threshold!effects!246!
of!a!motorway!on!anuran!populations!in!Ontario,!Canada.!A+'$'09&"4>&;'+*1,9!14$[online].!247!
!248!
Foresman!KR!(2003)!Small!mammal!use!of!modified!culverts!on!the!Lolo!South!Project!of!249!
Western!Montana.!In:!.-'+11>*40%&'(&,/1&?4,1-4",*'4"$&@'4(1-14+1&'4&A+'$'09&"4>&B-"4%2'-,",*'4!250!
(Eds!C!L!Irwin,!D!Nelson,!and!K!P!McDermott)!pp!342–343!(Center!for!Transportation!and!The!251!
Environment,!North!Carolina!State!University,!Raleigh,!NC).!252!
!253!
Forman!RTT,!Sperling!D,!Bissonette!JA,!Clevenger!AP,!Cutshall!CD,!Dale!VH,!Fahrig!L,!France!R,!254!
Goldman!CR,!Heanue!K,!Jones!JA,!Swanson!FJ,!Turrentine!T!and!Winter!TC!(2003)!C'">&1+'$'09M&255!
;+*14+1&"4>&%'$3,*'4%!(Island!Press:!Washington).!256!
!257!
Gilbert!M!(1998)The!Australian!partnership!approach!to!protecting!roadside!habitats!In!258!
.-'+11>*40%&'(&,/1&?4,1-4",*'4"$&@'4(1-14+1&'4&6*$>$*(1=&A+'$'09&"4>&B-"4%2'-,",*'45&pp!10–12.!!259!
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Goldingay!RL,!Rohweder!D!and!Taylor!BD!(2013)!Will!arboreal!mammals!use!rope-bridges!261!
across!a!highway!in!eastern!Australia?!N3%,-"$*"4&!"##"$'09!35,!30–38.!262!
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Goosem!M!(2001)!Effects!of!rainforest!roads!on!small!mammals:!inhibition!of!crossing!264!
movements.!6*$>$*(1&C1%1"-+/!28,!351–364.!265!
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Gulle!N!(2006)!Home!range!use!and!road!crossing!behaviour!by!the!common!brushtail!possum!267!
B-*+/'%3-3%&:3$21+3$"5!(Honours!Thesis,!The!University!of!Melbourne).!268!
!269!
Holderegger!R!and!Di!Giulio!M!(2010)!The!genetic!effects!of!roads:!A!review!of!empirical!270!
evidence.!<"%*+&N4>&N22$*1>&A+'$'09!11,!522–531.!271!
!272!
Huijser!M!and!McGowan!PT!(2003)!Overview!of!animal!detection!and!animal!warning!systems!273!
in!North!America!and!Europe.!In:!.-'+11>*40%&'(&,/1&?4,1-4",*'4"$&@'4(1-14+1&'4&A+'$'09&"4>&274!
B-"4%2'-,",*'4!(Eds!C!L!Irwin,!D!Nelson,!and!K!P!McDermott)!pp!368–382!(Center!for!275!
Transportation!and!The!Environment,!North!Carolina!State!University,!Raleigh,!NC).!276!
!277!
Jaeger!JAG!and!Fahrig!L!(2004)!Effects!of!road!fencing!on!population!persistence.!@'4%1-:",*'4&278!
<*'$'09!18,!1651–1657.!279!
!280!
Jellinek!S,!Parris!KM,!McCarthy!MA,!Wintle!BA!and!Driscoll!DA!(2014)!Reptiles!in!restored!281!
agricultural!landscapes:!The!value!of!linear!strips,!patches!and!habitat!condition.!N4*#"$&282!
@'4%1-:",*'4!17,!544–554.!283!
!284!
Jones!ME!(2000)!Road!upgrade,!road!mortality!and!remedial!measures:!Impacts!on!a!population!285!
of!eastern!quolls!and!Tasmanian!devils.!6*$>$*(1&C1%1"-+/!27,!289–296.!286!

!
8!
!287!
Lesbarreres!D!and!Fahrig!L!(2012)!Measures!to!reduce!population!fragmentation!by!roads:!288!
what!has!worked!and!how!do!we!know?!B-14>%&?4&A+'$'09&R&A:'$3,*'4!27,!374–380.!289!
!290!
Mansergh!IM!and!Scotts!DJ!(1989)!Habitat!continuity!and!social!organisation!of!the!mountain!291!
pygmy-possum!restored!by!tunnel.!O'3-4"$&S(&6*$>$*(1&!"4"01#14,!53,!701–707.!292!
!293!
Major!RE,!Smith!D,!Cassis!G,!Gray!M!and!Colgan!DJ!(1999)!Are!roadside!strips!important!294!
reservoirs!of!invertebrate!diversity?!A!comparison!of!the!ant!and!beetle!faunas!of!roadside!295!
strips!and!large!remnant!woodlands.!N3%,-"$*"4&O'3-4"$&'(&T''$'09!47,!611–624.!296!
!297!
McCall!SC,!McCarthy!MA,!van!der!Ree!R,!Harper!MJ,!Cesarini!S!and!Soanes!K!(2010)!Evidence!298!
that!a!highway!reduces!apparent!survival!rates!of!squirrel!gliders.!A+'$'09&"4>&;'+*1,9!15$299!
[online].!300!
!301!
Parris!KM!and!Schneider!A!(2009)!Impacts!of!traffic!noise!and!traffic!volume!on!birds!of!302!
roadside!habitats.!A+'$'09&"4>&;'+*1,9!14![online].!303!
!304!
Ramp!D!and!Ben-Ami!D!(2006)!The!effects!of!road-based!fatalities!on!the!viability!of!a!peri-305!
urban!Swamp!Wallaby!population.!O'3-4"$&'(&6*$>$*(1&!"4"0"#14,!70,!1615–1624.!306!
!307!
Ramp!D!and!Croft!DB!(2006)!Do!wildlife!warning!reflectors!elicit!aversion!in!captive!308!
macropods?!6*$>$*(1&C1%1"-+/!33,!583–590.!309!
!310!
Robinson!D!(2006)!Is!revegetation!in!the!Sheep!Pen!Creek!area,!Victoria,!improving!Grey-311!
crowned!Babbler!habitat?!A+'$'0*+"$&!"4"01#14,&"4>&C1%,'-",*'4!7,!93-104.!312!
!313!
Russell!TC,!Herbert!CA!and!Kohen!JL!(2009)!High!possum!mortality!on!urban!roads:!314!
implications!for!the!population!viability!of!the!common!brushtail!and!the!common!ringtail!315!
possum.!N3%,-"$*"4&O'3-4"$&S(&T''$'09!57,!391–397.!316!
!317!
Shepard!DB,!Kuhns!AR,!Dreslik!MJ!and!Phillips!CA!(2008)!Roads!as!barriers!to!animal!318!
movement!in!fragmented!landscapes.!N4*#"$&@'4%1-:",*'4!11,!288–296.!319!
!320!
Soanes!K!(2014)!Evaluating!the!success!of!road-crossing!structures!for!arboreal!mammals:!How!321!
does!monitoring!effort!influence!the!detection!of!population-level!effects?!(PhD!Thesis,!The!322!
University!of!Melbourne).!323!
!324!
Soanes!K,!Lobo!MC,!Vesk!PA,!McCarthy!MA,!Moore!JL!and!van!der!Ree!R!(2013)!Movement!re-325!
established!but!not!restored:!Inferring!the!effectiveness!of!road-crossing!mitigation!for!a!gliding!326!
mammal!by!monitoring!use.!<*'$'0*+"$&@'4%1-:",*'4!159,!434–441.!327!
!328!
Soanes!K,!Vesk!PA,!and!van!der!Ree!R!(2015)!Monitoring!the!use!of!road-crossing!structures!by!329!
arboreal!marsupials:!insights!gained!from!motion-triggered!cameras!and!passive!integrated!330!
transponder!(PIT)!tags.!6*$>$*(1&C1%1"-+/!42,$241–256.$$331!
$332!
Suckling!GC!(1984)!Population!ecology!of!the!sugar!glider!Petaurus!breviceps,!in!a!system!of!333!
fragmented!habitats.!N3%,-"$*"4&6*$>$*(1&C1%1"-+/!11,!49–75.!334!
!335!
Taylor!BD!and!Goldingay!RL!(2003)!Cutting!the!carnage:!wildlife!usage!of!road!culverts!in!336!
north-eastern!New!South!Wales!.6*$>$*(1&C1%1"-+/!30,!529–537.!337!
!338!
Taylor!BD!and!Goldingay!RL!(2004)!Wildlife!road-kills!on!three!major!roads!in!north-eastern!339!
New!South!Wales.!6*$>$*(1&C1%1"-+/!31,!83–91.!340!

!
9!
!341!
van!der!Grift!EA,!van!der!Ree!R,!Fahrig!L,!Findlay!S,!Houlahan!J,!Jaeger!JAG,!Klar!N,!Madriñan!LF!342!
and!Olson!L!(2013)!Evaluating!the!effectiveness!of!road!mitigation!measures!<*'>*:1-%*,9&"4>&343!
@'4%1-:",*'4!22,!425–448.!344!
!345!
van!der!Ree!R!(2006)!Road!upgrade!in!Victoria!a!filter!to!the!movement!of!the!endangered!346!
Squirrel!glider!(.1,"3-3%&4'-('$+14%*%):!Results!of!a!pilot!study.!A+'$'0*+"$&!"4"01#14,&R&347!
C1%,'-",*'4!7,!226–228.!348!
!349!
van!der!Ree!R!and!Bennett!AE!(2003)!Home!range!of!the!squirrel!glider!(.1,"3-3%&4'-('$+14%*%)!350!
in!a!network!of!remnant!linear!habitats.!O'3-4"$&S(&T''$'09!259,!327–336.!351!
!352!
van!der!Ree!R,!van!der!Grift!EA,!Mata!C!and!Suarez!F!(2007)!Overcoming!the!barrier!effect!of!353!
roads!–!how!effective!are!mitigation!strategies?!!An!international!review!of!the!effectiveness!of!354!
underpasses!and!overpasses!designed!to!increase!the!permeability!of!roads!for!wildlife.!In:!355!
.-'+11>*40%&'(&,/1&?4,1-4",*'4"$&@'4(1-14+1&'4&A+'$'09&"4>&B-"4%2'-,",*'4!(Eds!C!L!Irwin,!D!356!
Nelson,!and!K!P!McDermott)!pp!423–431!(Center!for!Transportation!and!The!Environment,!357!
North!Carolina!State!University,!Raleigh,!NC).!358!
!359!
van!der!Ree!R,!Clarkson!DT,!Holland!K,!Gulle!N!and!Budden!M!(2008)!C1:*1H&'(&!*,*0",*'4&360!
!1"%3-1%&3%1>&,'&>1"$&H*,/&,/1&?%%31&'(&U"7*,",&D-"0#14,",*'4&79&!"V'-&K*41"-&?4(-"%,-3+,3-1,!361!
Report!for!Department!of!Environment,!Water,!Heritage!and!the!Arts!(DEWHA).!362!
!363!
van!der!Ree!R,!Heinze!D,!McCarthy!M!and!Mansergh!I!(2009)!Wildlife!tunnel!enhances!364!
population!viability,!A+'$'09&"4>&;'+*1,9!14.$365!
!366!
van!der!Ree!R,!Cesarini!S,!Sunnucks!P,!Moore!JL!and!Taylor!AC!(2010)!Large!gaps!in!canopy!367!
reduce!road!crossing!by!a!gliding!mammal.!A+'$'09&"4>&;'+*1,9!15$[online].!368!
!369!
van!der!Ree!R,!Smith!DJ!and!Grilo!C!(2015)!U"4>7''Q&'(&-'">&A+'$'095&(Wiley!Blackwell:!370!
London).!371!
!372!
!373!
!374!
!375!
!376!
!377!
!378!
!379!
!380!
!381!
!382!
!383!
!384!
!385!
!386!
!387!
!388!
!389!
!390!
!391!
!392!
!393!
!394!

!
10!
List$of$figures$395!
$396!
$397!
Figure$1$Map!of!roadless!areas!in!south-east!Australia!Green!indicates!locations!more!than!1!398!
km!from!the!nearest!road!Source:!Google!Earth!Engine,!Global!Roadless!Area!1km!buffer!399!
Accessed!20th!August,!2015$400!
$401!
$402!
$403!
Figure$2$Fragmented!remnant!habitat!for!squirrel!gliders!in!south-eastern!Australia!mostly!404!
occurs!as!linear!strips!along!roadsides!and!waterways!(Google!Earth!image!date!14/1/2014)!!405!
$406!
$407!

!
11!
$408!
Figure$3$Canopy!bridge!(a,c)!and!glider!pole!(b,d)!installed!along!the!Hume!Freeway!in!409!
northeast!Victoria!From!Soanes!1,&"$5!(2013)$$410!
!411!