Impact of a road on the movements of two ground beetle species (Coleoptera: Carabidae)

2006·0.65 MB·

by  Jinze Noordijk

©EntomologicaFennica.11October2006
Impact of a road on the movements
of two ground beetle species (Coleoptera: Carabidae)
JinzeNoordijk,DebbiePrins,MariannedeJonge&RikjanVermeulen
Noordijk,J.,Prins,D.,deJonge,M.&Vermeulen,R.2006:Impactofaroadon
themovementsoftwogroundbeetlespecies(Coleoptera:Carabidae).—Ento-
mol.Fennica17:276–283.
Westudiedtheeffectsofaroadonthewalkingdirectionsofthecarabidspecies
PoecilusversicolorandAgonumsexpunctatum.Usingmarkandrecaptureexper-
imentsandwindowtrapswedeterminedthenumberofroadcrossingsandthede-
viationinwalkingdirectionscausedbytheroad.Wefoundtwoeffectsoftheroad
onthewalkingbehaviour:(1)theroadisabarriertobothspecies,butwhereasP.
versicolorwasreluctanttocrosstheroadandhadasignificantmovementaway
fromtheroad,werecordednoroadcrossingsbyA.sexpunctatum;and(2)A.sex-
punctatumshowedamarkedtendencytowalkalongtheroadsideverge,particu-
larlyintheditch.Ofthesetwospecies,onlyoneindividualofA.sexpunctatum
wascaughtflyingclosetotheroad,indicatingthatitmightcrosstheroadbyfly-
ing.Countsofdeadcarabidspecimensontwo100mlongtransectsalongtheroad
carriedoutfornineweeksrecordedseveralindividualsofP.versicolor.Wecon-
cludewithsuggestionsonhowtoimplementtheresultsofthisstudyinnature
conservationpractices.
J.Noordijk,D.Prins&M.deJonge,WageningenUniversity,DepartmentofEn-
vironmental Sciences, Nature Conservation and Plant Ecology Group,
Bornsesteeg69,6708PDWageningen,theNetherlands;correspondentauthor’s
e-mail:[email protected]
D.Prins,M.deJonge&R.Vermeulen,StichtingWillemBeijerinckBiologisch
Station,Kanaaldijk36,9409TVLoon,theNetherlands
Received2November2005,accepted25March2006
1.Introduction 1990, Dyer et al. 2002, Koivula & Vermeulen
2005).Thosespeciesisolatedinareascutoffby
Roads have several negative ecological effects, roads may suffer a loss of genetic variability
such as habitat destruction and disturbance and withinthepopulations(Reh&Seitz1990,Keller
pollutionoftheenvironment(Forman&Alexan- & Largiadèr 2003), which might increase the
der1998).Besides,roadsalsohaveabarrieref- probabilityoflocalextinctions(Pulliam&Dun-
fect:formanyanimalstheyaredifficultoreven ning1997).
impossibletocross,andmanyindividualsendup In 2005 we studied carabid movement pat-
asroadkills.Variousspecies,fromsnailstocari- terns next to a provincial road running straight
bous,havebeenreportedashavingdifficulty in through the centre of the Mantingerveld nature
crossingroads(Baur&Baur1990,Maderetal. restoration area, in the north of the Netherlands
ENTOMOL.FENNICAVol.17 (cid:127) Impactofaroadoncarabidmovements 277
Fig.1.Locationandde-
velopmentofthe
Mantingerveldnature
restorationarea,illus-
tratedbymapsofthe
area.Theprovincialroad
studiedrunsthroughthe
middleofthisarea.White
areasarearablefields,
greyareasare
heathlands(andin1d
arealsoformerarable
fields),andblackareas
areforests.–a.Location
oftheMantingerveldin
thenorthoftheNether-
lands(blacksquare).
–b.Situationin1954.
–c.Situationin1990.
–d.Situationin2004.
Thelocationoftheroad
enclosureisindicatedby
acirclewithacross.
(Fig.1a).Inthisarea,theconversionofmorethan Koivula&Vermeulen2005).Maderetal.(1990)
2,000haofheathlandintoarablelandstartedin found that even narrow field tracks already had
1954(Fig.1b).By1959,only325haofheathland somebarriereffectonamixofopenareacarabid
remained, scattered throughout the area in five species,buttheydidnotdiscussspecies-specific
fragments. This situation persisted until the late results.Inthispaperweexaminewhetheraroad
1990s(Fig.1c).IntheNetherlands,habitatfrag- between two areas with relatively xeric and
mentationanddestructionbegantoattractpublic thermichabitatsisabarriertotwocarabidspecies
concerninthe1970sand1980s,resultinginthe that are abundant in the area. We measure
planning of the restoration, enlargement, and whethersuccessfulcrossingsdooccurbywalk-
reconnectionoftheremainingheathlands.Inor- ing or flying, and whether carabid beetles are
dertoconnectthefiveremnantsofheathlandin killedbytraffic.Wediscusswhethertheroadaf-
the Mantingerveld, the Dutch nature manage- fectsthedirectionofmovementofthetwocarabi-
mentorganisation‘Natuurmonumenten’isrestor- dspecies,asifthisisthecase,thismayhinderthe
ing the intervening arable fields into heathland freeexchangeofindividualsorevenspeciesbe-
and species-rich grassland by removing topsoil tweentheareasoneithersideoftheroad.
andintroducingheatherpropagules(Aertsetal.
1995).Thisstrategyhasledtoamoreorlessco-
herent and interconnected nature reserve with a 2.Materialandmethods
totalareaof1050ha(Fig.1d).However,theroad
stilldividestheMantingerveldintwo. 2.1.Locationandstudyspecies
Previous research on the barrier effect of
roads on carabid species has focussed on forest The N317 (known locally as the Hoogeveense-
species(Mader 1984, Keller &Largiadèr 2003, weg)isaprovincialroadwithanasphaltedsur-
278 Noordijketal. (cid:127) ENTOMOL.FENNICAVol.17
face 6.5 m wide, constructed around 1968 and
connecting the village of Westerbork with the
town of Hoogeveen. The field site (52º46’ N,
6º35’E)straddlesastretchoftheroadinthena-
turerestorationareathatisborderedtothewest
bytheHullenzandheathandtotheeastbyafor-
merarablefield,theGrooteVeld(Fig.1d).Onav-
erage,2,400carsusethisroadperday(datasup-
pliedbyDrentheProvince).Oneithersideofthe
road is a grassy verge. On the heathland side,
about 2 mfromthe road, the verge is separated
fromtheheathlandbyadryditch.
We used Poecilus versicolor (Sturm, 1824) Fig.2.Schematicrepresentationoftheexperimental
and Agonum sexpunctatum (Linnaeus, 1758) to set-upinthefield.Indicatedarethelocationsofthe
roadandcontrolenclosure,includingallthepitfall
study carabid walking behaviour close to the
traps(blackcircles).Markedbeetleswerereleasedat
road. These species were selected because they
thecentreofeachenclosure(blackstars).The
are common in the heathland area and the
transectsforcollectingtrafficcasualtieswerelocated
oligotrophicformerarablefieldsseemtoprovide
inthedirectionofthearrow.Thewindowtrapsonlyin-
a suitable habitat for them (Verhagen & Ver- terceptedcarabidsflyingfromtheheathlandtowards
meulen2005). theformerarablefield.
Poecilusversicolorisaeurytopicspeciesof
openareas(Turinetal.1991).Thoughitcanbe
foundinvarioustypesoflowvegetationonvari- theroadandtheother,acontrol,wasintheheath
ous types of soil, in the Netherlands it prefers about30mawayfromtheroadenclosure.Thedi-
sandy soils, and is most abundant in heathland ameteroftheroadenclosurewas19.4mandthat
(Turin 2000). It is macropterous and capable of ofthecontrolenclosure8.4m.Carabidswerecol-
flying,butonlyasmallpercentageofthepopula- lected in the surrounding area and marked by
tionhastheopportunitytodevelopwingmuscles makingsmallpitsintheelytrawithatinysolder-
(Desender1989).P.versicolorhasbeenrecorded ingiron.Themarkedindividualswerereleasedin
intheGrooteVeld,butinverylowdensitiescom- thecentreofthetwoenclosures.Drypitfalltraps
paredwiththeHullenzandheathland(Verhagen (diameter10cm,depth9cm)wereplacedabout
&Vermeulen2005). twomapartontheinsideofthefence,allatthe
In the Netherlands, the second species, samedistancefromthereleasepoint.Therewere
Agonumsexpunctatum,isacharacteristicspecies 13 traps in the control enclosure and 27 in the
of oligotrophic humid heathland areas (Turin et roadenclosure.Intheroadenclosure,1,188indi-
al.1991),althoughitcanoccurinothertypesof vidualsofP.versicolorand113individualsofA.
habitat.Thespeciesismacropterousandcapable sexpunctatumwerereleased.Thecorresponding
offlying,butaproportionofthepopulationhas numbersforthecontrolenclosurewere342and
reduced wings (Desender 1989). A. sexpuncta- 39 individuals. We recorded all individuals
tumiscommonintheHullenzandheathandwas trappedintheindividualpitfalltraps.
recently discovered in the Groote Veld (Arnold The pitfall traps in the circular enclosures
Spee,pers.comm.). were clockwise given values between 0° and
360°, starting with 0° at north and proceeding
clockwise.Intheroadenclosurethepitfalltraps
2.2.Experimentalenclosures between295°and345°wereexcludedfromsta-
tisticalanalysis,tocompensateforthegapsinthe
Using hardboard fencing we made two circular enclosurecausedbytheroad.Inthiswayaneven
enclosurestotestwhetherthepresenceofaroad distribution of sampling points was created, al-
altered the direction of movement of the two lowingthedirectionalpreferencesofthecarabid
carabidspecies(Fig.2).Oneenclosurestraddled beetles to be calculated. The directional prefer-
ENTOMOL.FENNICAVol.17 (cid:127) Impactofaroadoncarabidmovements 279
Fig.3.Recaptureresults
oftheroadandthecon-
trolenclosureforboth
carabidspecies.Thetri-
anglesindicatethedirec-
tionofthepitfalls(at-
tachedtothefence)
wheretheindividuals
werecaught.Thelength
ofthetrianglesispropor-
tionaltothenumberofre-
capturesinthatdirection
andisnotcomparable
betweenthecircles.–a.
WalkingpatternofP.ver-
sicolorintheroadcircle
(380individuals).–b.
WalkingpatternofA.
sexpunctatumintheroad
circle(45individuals).–c.
WalkingpatternofP.
versicolorinthecontrol
circle(164individuals).–
d.WalkingpatternofA.
sexpunctatuminthecon-
trolcircle(13individuals).
encesinbothenclosures,expressedasmeanvec- close to the road enclosure, between the heath-
tor length and mean angle, were calculated ac- land and the former arable field. The second
cordingtoBatschelet(1981),usingthenumberof transectwasbetweensomepatchesofwoodland
recapturesinthedifferenttraps.Tostudyapossi- andanarablefield.
blebimodaldirectionalpreference,thedatawere
transformedbymultiplyingtheangleofeachre-
capturedindividualbytwoandthenrecalculating 2.4.Windowtraps
themeanvectorandangle.
Thesignificanceofmeanangleswasanalysed On either side of the road we placed a window
withaRayleightestforrandomness(Batschelet trapclosetotheroadtointerceptcarabidsflying
1981). Differences in distribution of walking from the heathland towards the former arable
preferencesbetweentheroadandthecontrolen- field(Fig.2).Aplexiglasswindow(1m×1m)in
closurewereanalysedwithchi-squaretests,after ametalframewaspositionedwithitsloweredge
poolingthepitfalltrapsinbothenclosuresinthree about one metre above ground level. A 15 cm
parts (between 225–295°, 345–55° and 105– wide gutter filled with a formalin solution was
175°). placed under one side of the window to collect
carabidsthatflewintothewindowenroutetothe
formerarablefield.Thewindowtrapswereemp-
2.3.Trafficcasualties tiedweeklyfrom15Aprilto26May.
Duringnineweeks(from31Marchto3June)we
collectedandidentifiedcarabidskilledbytraffic. 3.Results
Thecollectionwasdonedaily onweekdays,on
twotransectsof100movertheentireasphalted 3.1.Experimentalenclosures
surfaceoftheroadandextendingonemetreinto
thevergeoneitherside.Ittookapproximately30 In the road enclosure the recapture rate for P.
minutestofinishonetransect.Onetransectwas versicolor was 32% (380 individuals). Twenty-
280 Noordijketal. (cid:127) ENTOMOL.FENNICAVol.17
Table1.Carabidsfounddeadontheroadandina Table2.Carabidspeciescaughtusingwindowtraps
smallstripofbothverges.Thecollectionwasdoneon placedoneithersideoftheroadtocapturebeetlesfly-
twotransectsof100m;transect1waslocatedinbe- ingfromtheheathlandtowardstheformerarablefield.
tweentheheathlandandtheformerarablefield, Windowtrap1waslocatedattheheathlandsideof
transect2wasbetweensomepatchesofwoodland theroadandwindowtrap2waslocatedontheformer
andanarablefield. arablefieldsideoftheroad.
Species Tran- Tran- Species Trap1 Trap2
sect1 sect2
Acupalpusbrunnipes(Sturm,1825) 7 –
AmaranitidaSturm,1825 1 – Agonummeulleri(Herbst,1784) 1 1
Amarasp. 1 2 Agonumsexpunctatum(Linnaeus,
Calathusmelanocephalus(Linnaeus, 1758) 1 –
1758) – 1 Amaraaenea(Degeer,1774) 16 9
CarabusarvensisHerbst,1784 3 – AmaraanthobiaVilla&Villa,1833 3 2
CarabusnemoralisMüller,1764 5 2 AmarafamelicaZimmermann,1832 15 13
CarabusproblematicusHerbst,1786 – 2 AmaralunicollisSchiødte,1837 31 13
Harpalusaffinis(Schrank,1781) – 1 AmaranitidaSturm,1825 14 15
Harpalussp. 1 1 Amaraplebeja(Gyllenhal,1810) 1 –
Poecilusversicolor(Sturm,1824) 2 5 Amarasimilata(Gyllenhal,1810) 1 –
Pterostichusniger(Schaller,1783) – 1 Anchomenusdorsale(Pontoppidan,
Pterostichusoblongopunctatus 1763) 2 –
(Fabricius,1787) 1 – Ansiodactylusbinotatus(Fabricius,
1787) 4 3
Calathusmelanocephalus(Linnaeus,
1758) 21 34
HarpalusrufipalpisSturm,1818 11 16
four of the 380 recaptured individuals had Harpalusaffinis(Schrank,1781) 3 8
crossedtheroad.Thisisfarfewerthanwouldbe Pterostichusstrenuus(Panzer,1797) 1 1
Pterostichusvernalis(Panzer,1796) 14 7
expectedifthebeetlemovementswererandom.
Stenolophusteutonus(Schranck,1781) – 4
P.versicolorshowedasignificantmovementper-
pendiculartotheroad,withthemeananglebeing
298°(r=23.0,df=331,p<0.001)(Fig.3a).
In the road enclosure the recapture rate for theroadenclosurewiththoseinthecontrolenclo-
A.sexpunctatumwas39%(45individuals).The sure revealed a clear difference in direction of
barriereffectoftheroadforA.sexpunctatumwas movementforbothspecies(¤2=50.7,df=2,p
evenstronger:notasingleindividualhadcrossed <0.001 for the former and ¤2 = 14.1, df = 2, p
theroad.However,nosinglepreferreddirection <0.001forthelatterspecies).
wasfoundforthisspecies,apparentlybecausethe
dataexhibitedaverystrongbimodaldirectional
3.2.Trafficcasualties
preferencealongsidetheroad,particularlyinthe
ditch (Fig. 3b). A modified Rayleigh test con-
Wecollected29deadindividualsofeightcarabid
firmedthis(r=0.88,df=44,p<0.001).
speciesfromtheroad(Table1).Theseincluded
Inthecontrolenclosuretherecaptureratesfor
sevenindividualsofP.versicolorandthreeindi-
P. versicolor and A. sexpunctatum were respec-
viduals of the stenotopic heathland species
tively 48%(164individuals)and33%(13indi-
CarabusarvensisHerbst,1784.
viduals).Nodirectionalpreferencewasfoundfor
P.versicolorinthisenclosure(Fig.3c).Though
A.sexpunctatumhadapreferenceforthesouth- 3.3.Windowtraps
west,withthemeananglebeing217°(r=0.50,df
=14,p=0.027)(Fig.3d).Weattributethisfinding Wecollected272individualsofeighteencarabid
tothelownumberofrecaptures. species from the window traps that intercepted
Comparingthedistributionofthewalkingdi- flightsfromtheheathlandtowardstheformerara-
rectionsofP.versicolorandA.sexpunctatumin blefield(Table2).Thecatchesincludedoneindi-
ENTOMOL.FENNICAVol.17 (cid:127) Impactofaroadoncarabidmovements 281
vidualofA.sexpunctatum,butitwasinthewin- We found three individuals of C. arvensis
dow trap on the heathland side of the road. No killed by traffic. This stenotopic heathland spe-
otherheathlandordriftsandspeciesweretrapped ciesisconsideredrareintheNetherlands(Turin
inthewindowtraps. 2000).Otherroadkillswefoundincludedmam-
mals, birds, amphibians and a reptile (data not
shown).Thesefindingsillustratethattraffichasa
4.Discussion directimpactontargetspeciesofheathlandcon-
servation,especiallyconsideringthediscrepancy
4.1.Effectsoftheroad betweenthenumberofanimalskilledby traffic
andthelownumberofindividualsfoundduring
Wefoundtwoeffectsoftheroadonthewalking surveys(Slater2002).Ourfailuretotrapspecific
behaviourofthetwocarabidspecies.Firstly,the heathland and driftsand carabid species flying
road prevents both species from moving freely closetotheroad(exceptforoneindividualofA.
betweentheareasonbothsidesoftheroad:We sexpunctatum)indicatesthepossibilitythateven
base this assertion on our finding that P. versi- flyingstenotopicspeciesmayexperienceroadsas
colorrarelycrossedtheroadandhadasignificant barriers(Askling&Bergman2003,Bhattacharya
preferencetomoveaway fromtheroad,andon etal.2003,Lauranceetal.2004).
thelackofrecordedinstancesofA.sexpunctatum We conclude that although ‘Natuurmonu-
crossing the road. The stronger reaction of A. menten’ aims at developing the Mantingerveld
sexpunctatummightbecausedbythefactthatitis into one coherent nature reserve, the road pre-
smallerthanP.versicolorandismorerestrictedto ventscarabidsfrommovingfreelyandalsoputs
humidsituations,soitwillexperiencetheasphalt theirpopulationsunderextrapressurebycausing
asanunsuitableenvironment.Similarbarrieref- deathsofindividuals.
fectshavebeenfoundforothercarabids(Mader
1984,Koivula&Vermeulen2005).Ourexperi-
mentconfirmsthatroadsarebarriersinheathland 4.2.Suggestionsforreducing
landscapes too. From this we infer that in the thebarriereffect
Mantingerveld area – that is fragmented by the
road–theremustbeisolatedpopulationsofsome Thebestwaytoundothebarriereffectofthepro-
carabid species. The fragmented heathland also vincialroadistorelocatetheroadoutsidethena-
reducesthelikelihoodofcarabidscolonizingthe turerestorationarea,butthisisnotarealisticop-
formerarablefields. tion. A successful mitigation measure for the
Thesecondeffectoftheroadwefoundwas heathland species might be a wildlife overpass.
themarkedtendencyofA.sexpunctatumtowalk Almostnoliteratureexistsontheuseofwildlife
alongsidetheroad,particularlyintheditch.Indi- overpasses by carabid beetles, so the effective-
viduals of P. versicolor also seemed to have a nessofthesestructuresislargelyunknown.Only
preferenceforparallelingtheroadandwalkingin Rietze(2002)hasshownthatseveralcarabidspe-
theditch.Maderetal.(1990)foundsimilarreac- cies use wildlife overpasses to cross the road
tionsofcarabidstoroadsandarailwaytrack.This whenthevegetationofthesourceareaissimilar
tendency to move parallel to transport routes tothevegetationontheoverpassandhabitatcor-
mightleadcarabidsawayfromtheirhabitatandit ridorstowardstheoverpassareprovided(seealso
might also increase the distance they have to Luelletal.2003).However,speciesofmoistand
travelbeforereachingthenextsuitablesite,with wet habitats are unlikely to use such structures
theriskthattheirenergysupplywillbeexhausted (Rietze2002).
before they reach that site (Mader et al. 1990). Abroadoverpasswouldfunctionbetterthana
Bothcarabidspecieswestudiedarerathercom- narrowoneanditwouldbebestfortheroadtogo
monandnotparticularlyvulnerable,soweexpect throughatunnel,sothattheoverpasswouldbeat
theroadtobeanevenmoreprominentbarrierto the same level as the surrounding landscape. If
more stenotopic animals, especially if they are theoverpassiscoveredwiththepreferredvegeta-
smalland/orflightless. tionofthetargetspeciesoftheMantingerveld,a
282 Noordijketal. (cid:127) ENTOMOL.FENNICAVol.17
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malscouldcrosstheroadwithoutbeingkilled.
gotten group of animals in infrastructure planning?
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ploited to provide helpful connections between
tationcausedbymajorroadsleadstoreductionofgene
scatterednaturereserves.
flowandlossofgeneticvariabilityingroundbeetles.
—ProceedingsoftheRoyalSocietyofLondonB270:
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