©EntomologicaFennica.17August2012 Red-listed Aradus laeviusculus (Hemiptera: Aradidae) inhabits burnt restoration sites in the Koli National Park, North Karelia, Finland HeliViiri*&KalleEerikäinen Viiri, H. & Eerikäinen, K. 2012: Red-listed Aradus laeviusculus (Hemiptera: Aradidae)inhabitsburntrestorationsitesintheKoliNationalPark,NorthKare- lia,Finland.—Entomol.Fennica23:63–68. WepresentnewrecordsoftheflatbugAraduslaeviusculusReuter,1875,anear threatened species, in North Karelia, Eastern Finland. Three adult individuals werecaughtinsprucebarkbeetlepipetrapsduringtheconsecutivetimeperiods of 22.V–22.VI.2006, 21.VII–22.VIII.2006 and 23.VII–25.VIII.2008 at a site thathadbeenburntforrestorationpurposeson7.VII.2005.A.laeviusculushad beenconsideredtobeanextinctspeciesinFinlanduntilonespecimenwasfound inKoliNationalParkin1996.Herewediscussthepossibilitythatslash-and-burn andrestorationburntreatmentsmaysustainthecontinuumofpost-firehabitats essentialfortheA.laeviusculuspopulation. H.Viiri*&K.Eerikäinen,FinnishForestResearchInstitute,EasternFinland RegionalUnit,Joensuu,P.O.Box68,FI-80101Joensuu,Finland;*Correspond- ingauthor’se-mail:[email protected] Received27September2010,accepted11October2011 1.Introduction that restoration treatments of mature spruce fo- restsmimickingtheconsequencesofnaturalhaz- Theamountofdecayingwoodisoneofthekey ardsresultinhigherdensitiesofmanyinsectsthat factors affecting the diversity of forest species. dependondecayingorburnttrees,suchasbark Quantitative aspects of decaying wood are also beetles (e.g., Eriksson et al. 2005). The tech- stronglyassociatedwiththequalityofdecaying niques commonly applied for the production of wood. In Finland, the reduction of burnt forest decayingwoodinborealforestswithamanage- areas and other young stages of natural succes- ment history are ring-barking and the felling of sionistheprimarycauseendangering58threat- individualtreesorgroupsoftrees.Highlyinten- ened species, the reason of decline for 30 near siveburningtreatmentsmaydamagelivingtrees threatened(NT)species,andthecauseofextinc- evenoutsidetheedgesofburnt-overrestoration tion for altogether seven species (Rassi et al. areas. The higher the treatment intensity is, the 2010).Extensivemanagementmeasurescanim- greater is the risk of bark-beetle infestations. prove the situation, since threatened forest spe- Therefore,extensiveuseofthosetechniquesmay cies benefit significantly from specific habitat notbepracticalclosetoforestryareas. restoration actions such as prescribed burning Varioustechniqueshavebeenappliedinorder (Hyvärinenetal.2006). toproducedecayingandburntroundwoodinthe However, there are good reasons to assume restorationofeven-agedmanagedsprucestands 64 Viiri&Eerikäinen (cid:127) ENTOMOL.FENNICAVol.23 within the area of the Koli National Park (Koli thetrappingdatathatrevealedtheoccurrenceof NP) (Eerikäinen et al. 2007). Restoration burn- A. laeviusculus span the period from 2005 to ings, including slash-and-burn treatments, have 2008. beencarriedoutintheNPtoproducethefreshly burnt boreal forests necessary to preserve the 2.2.Studyareaandsites habitatsrequiredbymanyred-listedspeciessuch as Aradus laeviusculus Reuter, 1875, a flat bug TheKoliNPislocatedinoneoftheeasternmost found for the first time in the Koli NP in 1996 regions of Southern Finland and comprises the (Lappalainen&Simola1998).Thisstudyreports centralareasoftheKarelianforesthillareacon- newevidenceofthisnearthreatenedfire-adapted sideredtobetheFinnishnationallandscape.The flat bug and evaluates the current status of the Koli NP is particularly famous for its heritage species in Finland. Three adult specimens were landscapes,namelywoodedpasturesandmead- foundinoneburntrestorationsiteasanon-target ows, which are the remnants of the traditional catchofIpstypographusL.pheromonetrapping slash-and-burnagriculturethatwaswidelyprac- intheKoliNP,NorthKarelia. ticedinKolifromthe18thcenturyuntilthe1930s. The restoration of slash-and-burn-derived habi- tatsandlandscapesbeganintheNPin1994(e.g. 2.Materialandmethods Eerikäinenetal.2007).Theforestinventoriesas well as habitat and species-specific surveys im- 2.1.Pheromonetrapping plementedinthe1990sshowedthattheconserva- tionstatusoftheareawasnotoptimalsincemore In order to monitor the possible changes in the than20%oftheforestsofKolihadbeenestab- spruce bark beetle (I. typographus) population lishedbyplantingandwerebeingmanagedinten- originating from restoration, a pheromone trap- sivelybeforetheestablishmentoftheNPin1991. ping programme, implemented annually, was The forests lacked decayed wood and natural launched in 2005. Spruce bark beetle trapping fires,andinherb-richforests,spruceswereinevi- was conducted using the 1979 black drainage tablybecomingdominant. pipetrapmodeldescribedbyBakkeetal.(1983) Inordertoensuretheprotectionofthevalu- and produced by Borregaard Ind. Ltd., Sarps- able habitat types and the diversity of species borg,Norway.Thetubeis135cmlongand12cm found in the Natura 2000 area, a LIFE-Nature indiameterandhasabout900evenlydistributed projectentitled“LIFEtoKoli–Restorationofthe holes.ThetrapswerebaitedwithIpsowit®stan- forests and meadows of the National Park” dard pheromone dispensers (Witasek Pfanzen- (LIFE2003NAT/FIN/000035)wascarriedoutin Schutz GmbH, Germany). The dispensers con- theKoliNationalParkin2003–2006.Theproject tained methyl-butenol, cis-verbenol and ipsdi- wascoordinatedbytheFinnishForestResearch enolpermeatedinacellulosesheetenclosedina InstituteandwaspartlyfundedbytheEuropean polyethylene bag attached inside the pipe trap. UnionthroughitsLIFE-Natureprogramme.The The fluid containers of pipe traps were filled to LIFE-Natureprojectdrewuplong-termmanage- halfwaywith70%alcohol. mentandrestorationplansforforests,meadows, Atrianglecomprisingthreetrapsspaced2m bog woodlands and slash-and-burn habitats, re- apart was placed at each collection site on spectively. By the end ofthe project there were 22.V.2005.Eachofthetrapgroupswaslocatedin ca.45hectaresoffreshlyburntborealforesthabi- anopenareaabout50mfromthenearestforest tats(subtypeforborealforests),ditchesblocked edge. The traps were attached to dry wooden within28hectaresofdrainedbogwoodlandsand sticks about one meter from ground level. The anincreaseindecayingwoodwithin107hectares trapswereemptiedonceamonth,alwaysaround offormermanagedforestsonmineralsoils(Eeri- the22nddayofthemonth,duringtheperiodfrom käinenetal.2007). MaytoSeptember.Themethodologyappliedin The sites monitored with spruce bark beetle KoliNPcorrespondstothatusedbyWeslienetal. pheromone trapping until 2008 comprised two (1989)andValkamaetal.(1997).Inthispaper, burnt and two ring-barked forest compartments ENTOMOL.FENNICAVol.23 (cid:127) Araduslaeviusculusinburntsites 65 Table1.Locationofstudysitesin2005(sites1–8)and2006–2008(sites1–11).Thegeographicalcoordinates givenarefromtheWGS84system. Trapgroup/Site Treatment N/lat. E/lon. 1Paimenenvaara Matureforest 63°5.134’ 29°47.704’ 2Paimenenvaara Matureforest 63°5.635’ 29°47.633’ 3Ukko-Koli,lowerslope Burning 63°5.816’ 29°49.053’ 4Likolahti(alongtheroad“Rantatie”) Burning 63°5.34’ 29°50.008’ 5Sikoniemi,Autiolahti Clear-cutting 63°4.23’ 29°51.974’ 6Sikoniemi,Autiolahti Clear-cutting 63°4.135’ 29°52.142’ 7Ala-Murhi Ring-barking 63°2.42’ 29°55.516’ 8Ala-Murhi Ring-barking 63°2.447’ 29°55.649’ 9Savikylä,Riihilahti Clear-cutting 63°8.87’ 29°41.593’ 10Savilahtifarm,Savilahti Clear-cutting 63°7.733’ 29°39.561’ 11Ukko-Koli,lowerslope Burning 63°5.785’ 29°49.145’ (Table1).Forreferencedata,wetrappedinsects ment no. 1383) where mature Norway spruce infourfreshclear-cutareasandtwomatureman- treeshadbeencutdowninthesecondhalfofJune agedforestsinthesurroundingareasoftheKoli 2004andwhichhadbeenburnton7thJuly2005. NP(Table1).Themonitoringstartedin2005and Thedistancebetweentherestoredcompartment wasbasedontwotrapgroupsforeachofthefour no.1383andtheslash-and-burnareainwhichthe treatment(sites1–8),butin2006itwasenlarged firstA.laeviusculusspecimenwascaughtin1996 totwofreshloggingsiteswhichhadbeenlogged islessthantwokilometres.AllAradidaespecies during the previous winter 2005–2006, (sites 9, caughtintrapswerechecked;nootherA.laevi- 10).Inaddition,onetrapgroup(site11)waslo- usculusindividualswereobservedatothertrap- catedwithinthesamerestorationburningareaas pingsites. trapgroup3,attheslopeofUkko-Koli. 4.Discussion 3.Results The slash-and-burn and restoration operations One adult female individual of A. laeviusculus carriedoutintheKoliNPinEasternFinlandhave wascaughtbetween22ndMayand22ndJune2006 inevitablycreatedacontinuumofburntwoodin (Ukko-Koli, Lieksa, Kb, Finland, Geographic thearea,leadingtofavourablebreedingsitesfor WGS84 coordinates: N 63° 5.785’ and E 29° A.laeviusculus.Itisworthmentioningthatslash- 49.145’) and another adult female between 21st and-burntreatmentshavebeencarriedoutcontin- July and 22nd August 2006 (Ukko-Koli, Lieksa, uously in the northernmost sites ofthe Koli NP Kb,Finland,coordinates:N63°5.816’andE29° since 1994, making it possible for fire-adapted 49.053’) in the very same burnt clearing with speciestosurviveintheprotectedarea(Fig.1). standingtreestemsandstemslyingontheforest There is probably a permanent A. laeviusculus floorbutfromdifferentgroupsoftraps(seeFig.1 populationinRussianCarelia,whereforestfires forlocatingthesites).Inadditiontothefindings aremorecommonthanontheFinnishsideofthe for2006,oneadultfemaleindividualwascaught border.Thespecieshasanorthernborealoccur- fromthesamerestorationsitebetween23rdJuly renceinRussiabutisabsentfromCentralEurope and25thAugust2008(coordinates:N63°5.785’ (Sandström & Wikars 2007). According to andE29°49.145’.Therewerenootherobserva- Johansson et al. (2010), the much higher total tionsofthespeciesin2007orinothertrapping abundanceandspeciesrichnessintheburntarea sites. inthefirstsummerafterthefireindicatesthata The trap groups were located on the lower forestfireattractsflatbugsfromrelativelygreat slopeinaclearingofabout1.5hectares(compart- distances. 66 Viiri&Eerikäinen (cid:127) ENTOMOL.FENNICAVol.23 Fig.1.Aradus laeviusculusre- cordsonslash- and-burnand burntrestoration areasintheKoli NationalPark, EasternFinland. Records of A. laeviusculus have remained listedasextinctinFinlandontheRedListofthe rareinFinland,NorwayandSweden(Sandström early1990s(Rassietal.1992),whenthemostre- &Wikars2007).Thespecieswasconsideredto cent recording was the one made in 1949 in be common in Finland in the beginning of the Lammi, South Finland (Heliövaara & Väisänen 1900s,whenitwasfoundalmosteverywherein 1983).Thespecieswasre-discoveredinFinland Varsinais-Suomi (Ab), Uusimaa (N), Satakunta aslateas1996whenitwasdetectedintheKoli (St),SouthHäme(Ta),SouthOstrobothnia(Oa), NP (Lappalainen & Simola 1998). Later it was North Häme (Tb), Middle Ostrobothnia (Om), discovered that the species had previously been Kainuu (Ok), North Ostrobothnia (Ob), Kemi observed in 1990 and 1993 in Kb:Lieksa and Lapland (Lk, W Part) and Inari Lapland (Li) Ok:Suomussalmi, respectively (ref. Hemiptera (Lammes & Rinne 1990). A. laeviusculus was InformationDatabase).Intheevaluationof2001, ENTOMOL.FENNICAVol.23 (cid:127) Araduslaeviusculusinburntsites 67 A.laeviusculus,wasclassifiedintothe“RedList isbelievedtocause80–90%ofallfiresinRussia category”of“endangered”,whereasin2010the and millions of hectares are burnt annually specieswascategorizedas“nearthreatened”(cf. (Karpachevskiy2004).In2009atotalof2.1mil- Rassietal.2001and2010). lion hectares of forest was burnt in Russia and The most recent unpublished findings have there were 23 200 registered forest fires which concentrated on restoration and forest burning destroyed 25.4 mill. m3 of wood (Anonymous sitesinEasternFinland(Rintala&Rinne2010). 2011). This amount has remained fairly consis- According to the Hemiptera Information Data- tentoverrecentdecades. base,A.laeviusculushasbeendetectedfromFin- Inthecurrentstudy,twoflatbugindividuals landduringthe1990’satsixsitesinNorthCarelia werecaughtintrapsonburntareasaboutoneyear (Kb) and Kainuu (Ok), four ofthesesites being after a fire. A. laeviusculus and A. crenaticollis slash-and burning sites. Recordings after 2000 have been described as pyrophilous flat bugs comprise12sitesinLieksa(Kb),Ilomantsi(Kb) (Wikars 1997). According to Schmitz et al. and Mäntyharju (Sa) in Eastern Finland. Alto- (2010), it is not clear that these species are at- gether30individualshavebeenfoundduringthe tracted by fire. They proposed that A. laevi- years 1990–2008, and ten of them were found usculusandA.crenaticollisarrivelaterthanspe- fromtheKoliNP.Thereforeitisworthtoassume cies equipped with IR receptors and, thus, have that the conservational status of A. laeviusculus not developed IR sensilla. Recently it has been has improved through restoration burnings car- shown that A. laeviusculus lacks this type of riedout,especially,intheeasternpartofFinland, sensillum(Schmitzetal.2010).Apossiblerea- nearthevastRussianborealforestareaswithreg- son for their pyrophilus-like behaviour may be ularityofnaturalforestfires. thatA.laeviusculusandA.crenaticollisaremy- Forest fires are quite rare in Finland nowa- cophagous and feed on fast-growing post-fire days.Therewasanaverageof1465reportedfo- fungi.Itisnotknownwhichfungithiswouldbe rest fires annually with an average size of 155 in the case of A. laeviusculus. Thus, there is a hectaresinFinlandduringthetimeperiod2000to need to study the habitat requirements of A. 2008.Between1980and1991thenumberoffo- laeviusculus more specifically. Jonsell et al. rest fires was even lower. Due to the intensive (2005)showedthattheoccurrenceofpolyporous managementofforestsandthesmallamountof fungi Fomitopsis pinicola (Sw.:Fr.) P. Karst. is dead wood and forestfires many Aradidaespe- crucialforthepresenceofAraduscorticalis(L.). ciesinFinlandarerareorthreatened.Thereare19 Fromthespeciesconservationpointofview, AradidaespeciesinFinlandandsixofthemare therestorationofmanagedforestclosetoexisting classified as regionally extinct (RE), vulnerable source areas is the most efficient approach (VU)ornearthreatened(NT)(Rassietal.2010, (Hanski2000)forpreservingsuitablehabitatsfor Rintala&Rinne2010).Mostofthesethreatened A.laeviusculus.Itisthereforerecommendedthat Aradus species are fire-adapted, requiring re- restorationburninginformermanagedforestsbe centlyburntwoodandpyrophilicfungitobesuc- continuedintheKoliNPinordertosustainthere- cessful. For some species, there are so few re- covering populations of flat bugs (Aradus spp.) cords that their habitat requirements are not and possibly other fire-habitat-dependent spe- known. cies. While planning further implementation of Many European and North American coun- suchtreatment,boththespatialandtemporalcon- tries are reintroducing prescribed burning since tinuumofsitesofrestorationburningshouldbe firesuppressionhasdecreasedtheprobabilityof examined, and a procedure for annual burning catastrophicfiresandmaybeacauseoftheex- treatmentsofevensmallforestblocksshouldbe tinctionofmanyplantandanimalspeciesthatare considered. More detailed information on the dependentonfirehabitats.InRussia,thesituation habitat requirements of A. laeviusculus would is different as its fire suppression system has benefitplanningandtheselectionofsitesforres- neverbeenveryeffectiveinmanagedforestsand torationburning.Finally,itisconcludedthatour huge parts of the country remain outside the resultssupportthefindingsofRassietal.(2010) scopeofforestfiresuppression.Humanactivity who stated that the fire-adapted Heteropteran 68 Viiri&Eerikäinen (cid:127) ENTOMOL.FENNICAVol.23 speciesseemtohavebenefitedfromongoingres- Johansson,T.,Hjältén,J.,Stenbacka,F.&Dynesius,M. torationburningactivities. 2010:Responsesofeightborealflatbug(Heteroptera: Aradidae)speciestoclear-cuttingandforestfire.— JournalofInsectConservation14:3–9. 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