ChrislineG. Niwa andRobert W Peck,Pac I c NorthwestResearch Stat on ForestrySc encesLaboratory 32OOSW Jefferson WaV, CorvaL s Oregon97331 enail address:cni\,!a@fs led us and Toroll R.Torgersen, Pac f c NorthwestResearch Stat on, Fofestryand FangeSc encesLaboratory, T40l Gekeer Lane,La Grande Oregon 97850

Soil,Litter, and CoarseWoody Debris Habitats for Arthropodsin EasternOregon and Washington

Abstract

Afthropods $ilhjn soil. littef. rnd coare woody dehris play vital rolcs in maintaining soil fenility, heallh. and productirity. Arthfopods shrcdplan! nrarerial,help nineralizc nutrientsfor plants.acr as prcdators.and serveas lbod lbr other wildlife. Some ,rpecieso| groups of speciesare poterlially !aluable for monitorirg lirrest hcalth. Natural and human causeddjsturbance may innediarel) kill many afthrcpods.bur changcsto habitat slruclure arc likely to cause longef-tem ellecls on their communrty composilions. Fire effeds on arrhropodsnrat be nrinimized ii rclugia of liuer and coarsewood) dcbris are retained.Possible ellects oftimber haNesting or Jllhropods include nechanical ctticts on soil and litter, microclimaic changes.and ihe addition of organic nrairerto rhe fbren lllror. Soil conrpactionreduces porc size. r'hich may fesult in loss of habilat and decrersednutrient fetendon. and rhanges the nicrobial and nematodecommunilics. which can aftecl nuuienl cycling and food resourceslbl nicroa hrcpods. Thfesholds rcquircd ibr health! ecos)stem funclion. and fredictile and decisiot suppori tools that include rheseconponcnts in relation to disturbanccsare not arailable.

Introduction thcy perfonn in thesegcosystem processes, ar thropod speciesor speciesguilds are potentially Plant growth and the long-terrn sustainabilityof valuablefor monitoring changcsin forcst health tbrest ecosystenrsdepcnd on the interaction of (Ginsbcrg1993. New 1995).An assessmentof soil tungi, microbes,and invefiebrates due to their inveftebratesof the interior Columbia Rivcr ba- rolcs in nutrient cycling and decomposition sin area(Niwa et al. 2001)discusses lunctional (Freckman199:1, Coleman and Crossley 1996). groupsof invertebratcs.including the roles they The soil and litter lbod web is among th(] most play in forest prooesses.conseNation and moni- biologically diverse part ol any terrestrial cco- toring of the invencbrate fauna, and the etleots systcm.Beyond numericabundance, these organ- ol managementnrdcli(e. on theseorpuni.ms. isms play vital roles in maintaining soil fertility, health,and productivity(Coleman et al. 1992). TheArthropod Fauna Arthropodsboth aboveand below ground arees- scntialto the comminution(shreddilg) of plant Microarthropodsinhabiting soil andlitter include material, which incleasesthe surfacearea avail- springtails,mites, proturans,diplurans. pseudo able for microbial colonization. Through gmz- scorpions.symphyJids, pauropods. and enchy- ing on bactcria and fungi, rnicroanhropodsin- traeids.Springtails and mitcs dominatethis faura fluencethe ratc at which nutrientsare mineralized in tems of abundance.biomass, species diver- (by rcgulatingmicrobial populations and by depo sity, and their effect on the nutrient cycling pro sition of $'aste prcducts) and become availablc cess.Springtails are small, wingless insectsi thcy to plants.Coa.rse $,oody debris (CWD) chewers have lapid growth rales and are often lbund in as a f'unctional group are impofiant to nutrient numbersofover 100,000per square meter ofsoil cyclingand decomposition, and also serre as an (Colemanand Crosslcy 1996). While somecot- imponant sourceof tbod fbr wildlife species. lembolan speciesare pledaceouson nematedes Macroanhropodssuch as ants, spiders, and beetles and othershave bcen found to feed on live plants are inrportantpfedators of othcr invertebratesin androots, the mdority arefungivores, often leeding thesehabitats, and are in turn prey for a variety selectivelyon pafticularspecies of fungi.The most ofvertebratespecics. Because ofthe criticalroles abundantsoil- andlitter dwellingmicroanhropods

NorthwcstScience, Vol. 75. Speciallssue. 200l 1,+I

a:r2001 bt rhc \onhwen Scientrll! A\\iudrntr. ]\ll ,,-!h[ tiered are soil mitcs from the four suborders:Oribatei. withinforest litter (Furniss and Carolin J977) and Prostigmata.Mcsostigmata. and Astigmata.ln are reportedto have a diet that includes algae. forcsts.oribatid miLesare the rnostnumerous soil decayingplant nratter. lichens, andlungi (Ferguson nxcroarlhropods,with densitiesas high as-500.000 1990).Solitary wasps build nestsin the soil,which pcr squaleneler (Walhvork1983). Oribatids are theyprovision with afihropodprey, providing food gencrally colsidercd to be fungal fceders.how tbr the devclopmentof their larvae.Ants have eversome species fccd on decomposingvegetable highly variablefeeding habits; many are consid mallcr' someare prcdaceous, some graze ()n bac ered opportunistic ornnivores.while others are teda,while othersconsunre both fungi andplant ma1orprcdalors of microarthropodsand impor- mateial. Many Prostigmatrare predators, with tanttree defoliating (Torycrsen er al. 1990). smallerspecics feeding on ncmatodesand soll- Many families ofbeetlcs inhabit the forestfloor: bodicJ unhrnpod:.A l(\\ ol lhc lrrgcr 'pecies many are predatory,while others are phybpha- prey on other ffthropods and their eggs.One of gous or saprophagous.Carabid ground bectles, the nost commonProstigmata species ntav be onc ol the most ecologically importantfatrilies. largelvalgivorous. Sone Prostigmataspecics t'eed havelong beenconsidered gencralist predators, un lttngiand are eupablc ofrrpitl increrserin re- feedingon a vadety of prey they cncounterwilhin productionin rcsponseto a suddenshift in avail- foresllitter Thereare numerous exceptions to this ablc resources.Mesostigmata miles are almost generalization,however: some ground bcetles aLre exclusively predators.with sometaxa feedingas known to beopponunistic foragers, primarily tak- tungir,ores.Astigmata ale trophicallydiverse and ing invefiebrateprey. but also feeding on plant includemycophagy. saprcphagy, phytophagy and food whcn available: some are nainly herbivo- parasitism.In gencral.they are poorly represented rcus (includingfruit and seeds):and someare in lbrest soils. bul have beenfound to be numer- highlv spccialized.such as thosethat fecd on earlh- ou: ir rnoi\lhabrrut: hiph in orElrni!maller u'omrs.snails and slugs (Thiele 1977, Hcngeveld (Colenanand Crossley 1996) as uell asin desert 19130).Other abundanr lirter-dwelling beerles in- soil (Whllwork 1972).Ovemll. the dietsof most clude predatory rovc beetles and click beetles, microafthropodsarc poorly known. which canbe destmctiyeroot feede$ during their Soil-and litter-dwelling macroafthropods en- larval stage.Insgcts from other orders, such as compassa wide range of taxonomic groups and grasshoppers,, and flies. contributc to soil ecologicalfunctions. Millipedes and isopods are and litter plocessesdu ng one or more stagesof important saprovores,contributing to the brcak thcirliie cycle. down ofdcad orgatricmatcrial. Isopods also teed The CWD-chevingcommunity is composed on roots or foliage of seedlings.Millipedes are of insccts tiom sevcral taxa, including beetles, key shreddersof leaflitter in somehabitats. Mil- wood wasps,ants, and tcrmites.Pdmary and sec, lipedesare least abundant in xeric regionsas they ondary bark beetlespenetrate the bark of weak lack a waxy epicuticle and are prone to desicca enedor freshly deadtrees and both inoculateand tion. Ccntipedesa.re common lbrest predators, proride acce.: lo \Jproph)ti\ microotgirni\Irs. capturingsmall arthropodssuch as collembolans Ambrosiabeetles may initiate colooizationofthe andspiders. Scorpions au.e noclumal predators with sapwoodaod inoculate galleries with mutualistic a diel thatincludes olhcr afihropods. Spiders and fungi. Both roundheadedand flatheadedwood- harveslmcnare considercdopportunistic, gener- boringbeetle larvae feed initially on the phloem alistpredators. though their huntingstrategies and ofdciid or dying trces,and go on to mine the sap- preyvary widely.Variation within web building wood andheafiwood (Fumiss and Carolin 1977). spidersincludcs loose, stringv webs. horizontal Wood-wasplarvac mine within the wood of trees sheet$'ebs. funncl webs. and thc popularly rec- that aredanaged or killed by fire, insects,dis- ogtnizcJ.r.oncentrre orh u eb..A jlcrnJli\ e .trate- er\e.and olher cruses. 51 mbiot ie fungiirle asro- giesto wcb buildinginclude active pursuit hunt- ciatedwith severalu'ood-wasp species. Carpen ing lnd lay and-waitambush hunting. Spide$ are ter antsreartheirvoung in neststhat they construct abundantin fbrestedccosystens. sontctinres num- by tunnelingin the wood ofstanding anddowned bering100 per squar e rneter(Coleman and Crosslev trees.They excavaterelatively dry wood in the lqqr)| Onel,mril)ofhri:tletails rMrihiliJael liri early stagesof decay.Termites occur in dead or l:12 Niwa. Peck.and Torgersen decaying wood, typically initiating excavation can bc al'fcctcdby their ubsence(Vossbrinck et within bark beetlcgallcrics. Tunnels are gradu- al. 1979.Santos et al. l98l). ally enlargedas fungi pervadethe wood.soften- Predationby soil, litter, and CWD-dwelling ing it and increasing its nutdtional value macroarthropodsis a major lbrce in forest lood (Schowalteret al. 1992).While not xylophagous, webs.In one study.spiders were shou'nto be the nany ofthe micro- andrnacroafthropods discussed dominant predato$. consuming:1,1% of all tbr- earlier use coalsewoody debrisfor the food and esttloor cryptozoans(Moulder and Reichlc 1972). habiratit provides(Seasredr et al. 1989). Ants areamong the primarylactors responsible for mortality of westem spruccbud*,orm popu- ArthropodFunction lations, parlicularly those fbraging in the lower crowns of trees (Tolgersenet al. 1990). Spiders It is widely recognizedthat micro- and nracro- ma)' be inlporlan{ prcdatorsof snrall budworm arthropodscontribute significantly to the sho - larvae.Several species ofspiders have been idcn- and long-term productivity of lbrest ecosystems tified as dominantpredators of the Douglas-fir (Seastedt1984, Moore et al. 19E8.Sha$'et al. tussockmoth (Wickman1977. Torgersen et al. 1991).Whilc microbes(principally bacteria and 1984,Mason and Torgersen 1987. Mason and Paul fungi) aredirectly responsiblefor decomposition 1988).The impactof predationon tussockmoth and fic majorityof nutrientcycling, rthropods population dynamicsmay be most intluential in contribute indirectly to theseprocesses. lndirect maintaining non-outbreaklcvcls rather than in inf'luenceson nutrientcycling include increasing reducingnumbers dudng outbreakconditions the surlace-to-volurncratio of organicpafticles (Mason 1987).Becausc of the wide varietyof availablefor microbialcontact, regulating microbc leeding modes found within spiders.thcv may nunbers through grazing. and facilitating con be panicularlyuseful indicaton of changein habitat lir(lhcl$cL'n tnieruhes rnrl lre\h,\rg.rni\ mitle- structureafter disturbance(Mclvcr et al. 1990). dal. Avariety of macrcafihropodsnomally con- Colonizationby a varietyofbeetles and wood tributeto the breakdownefplant materialthrough wasps initiates the proccssof structurill break- comminution. however.microarlhropods have bcen down ofa fallen tree,and hence release ofbound estimatedto contribute as much as 50c/rof this nutrients.and thcir cntrance holes serve as inlec- xctivity in some tbrest soils (Berthet 1967). tion coufis fol many decomposingl'ungi tind bac- Microarthropodscan facilitatemicrobial inocu- terir, which they otien transporton their bodies lationoforganic substratesbl moving either fungal (Harmonet al. 1986,Zhong andSchowalter 19E9. sporesto fieshmaterirl or viceversa (Behan and Shawet ll. l99l). By increasingwood porosity, Hill l9?8, Kitchellet al. 1979). aeration.and moisture retention of logs. CWD- chcwinginsects assist in the decompositionof grazing Microbial by microarthropodsinflu- Iogs in a manner sinilar to that obscrvedin the encesmicrobe abundances,although the extent decompositionoflitter by otherarthropod guilds. of grazingpressure appe rs to deterninehow Tunnelingby wood-boringbeetles and wasps microberlr< affcctcJ:u hcn grauirtC nres.ure is further degradesthe structureof thc wood and high, microbial activity is depressed.but when contributesto the topplingofsnags (Edmonds and grazingpressure is nroderate.microbial abundance Eglitis l9E9). Coloniesoftenr.ites and carpcntcr canbe enianced,atleast in someinstances (Hanlon ants enrich the nulricnt contentof the logs they and Andersonl9ll0, Colemanet al. J983).Se- uceupy.Ant. areearll inradingrepre\cnrdri\c\ lcctivcgrazing by springtails;rltered the outcome of the CWD-chewing guild and have beendem of competition betweentwo decomposcrbasidi- onsfated to be valuablc indicator taxa that are omycetes(Newell 198,1a,1984b). When micro readilydiscemable for monitoring(Torgersen and at1hrepodsgraze on tungi andbacteria. some of Bull 1995). the nitrogenbound in thesemicrobes is mineral- Numerous studieshave docunentcd the im- izedand releasedas nitrogenouswaste. making portanccof macroafthropodsresiding in soil,lit it available for uptake by roots. Studiesexclud- ter, eurdCWD asprey for vertebrates.ln the Bluc ing microafihfopods liom litter substates have Mountains of Oregon and Washington,shrews. shownthat decomposition urd mineralizationrates newts.salamanders, liogs. toads.and rubberboa

Soil, Litter, and CoarseWoodv Debris l,+3 prey on a variety of afihropods in the soil and A variety of studieshave investigatedthe ef- duff stratum.(Thomas I 979).Simil.uly, rthropods fect offire on soil and litter afthropodcommuni inhabiting CWD. including bark- and wood ties.However, most have either characterized the boring beetles.ants, *ood wasps.and termites athropod fauna following stand-replacingwild- scrvc as critical lbod resourcesfor wildlife firc (Frcnchand Keirle 1969,Hmis zurdWhitcomb species such as woodpeckersand bears 197:1,Richardson and Holliday 1982,Holliday (Torgersenand Bull 1995,Hanula and Franzreb 198,1)or examinedprescribed fire asa siteprcpa- 1997.Bull et al. 1lr2rzss). rationmcasurc (e.g. slash buming) fbllowing timber har,'est(Neumann 1991, Michacls and McQuillan 1995.Beaudry Etfects of Disturbance Regimes and et al. 1997).Overall, results tiom ManagementPractices thesestudies are mixed or inconclusive.with dis- turbanceresulting in greaterabundance and di Natural and anthropogcnicdisturbance cin aff'ect ve$ity in sone caseswhile leading to a dimin- arthropodsthrough direct moftality of individu ishcdand depauperxtearthropod tauna in others. als: however, long tefln effects may be caused Although these sludies suggest how some indirectly through changesin vegetativesucces- artbropodsrespond to variousforms of disturbance sionalpattems, physical and chemicalpropefties underccnain conditions, they do not indicatehow ofthe soil.predator abundance and composition, arthropodsmight respondto prescribedfirc within and numerousother factors that may affect the this geographicregion. habitat of theseorganisms in a positive or nega- Few studieshave looked specifically tit the ell'ert tivemanner. The dispersal capabilitics ofspecies of understoryfuels reductionbuming, in the ab- or guilds will atTectthe degreeto which these senceof confoundingtreatments, such as tree organismsand their llnctions areaffected and the ha esting,on arthropodcommunitics. In a par- anrountof time necessaryfor recolonizationand tiallv replicatedstudy in westem Montana, pre- recovery.Extri,rpolation fron previous work on liminary data indicated that one year following the impactsofdisturbance on soil,[tter, andCWD buming under a shelterwoodcut, soil and litter cheving arthropodsmust be done with extreme microarthropodpopulations had already rccov- caution. as many studiesare not replicated.few eredto the levcls ofthose in adjacentundisturbed havebeen conducted in ecosystemssimilarto those lbrests (Fellin 1980b). Most of the litter representedin castcrnOregon and Washington, macroafthropodgroups collected in this studywere andlittlc is known aboutlonger-term rcsponses adverselyaffected by intensiveand completere- or how ccosysten processesare atlected. rnoval of residuescompared to either leaving or buming residues(Fellin 1980a).In jarrah forests The directeffect offire on afthropodsdepends of WesternAustralia, Majer ( 1984)found ovcrall on tlre intensity,seasonal timing, and the amount abundance (of both micro- and of litter and other luels consumed.Direct mor- macroarthropods)to be lower in a burned plot tality due to fire may be of greatestcffect on comparedto an unbumed plot within litter but arthropodsthat havc relatively low dispersalca- found few differenceswithin soil. Similarly, pabilitics.Direct effectson afthropodsmay be Springett(1976), also working injarrah forests. minimizcdif refugiaof litter and CWD arere- found fewer macroafihropodsin burned forests trineJ.Frre-rcllt.J chJngc. in foresr.uer.e.'ion comparedto unburnedlbrests of similar struc- could potentially aifcct many trrthropodguilds. ture. However, both of thesestudies must be re- Burning rnay result in the removal of CWD gardedas generallyinconclusive with regardsto from the forest,but it can also be rcsponsiblefor fire becauseof weak or no replication and a lack the creationof additionalCWD throughtire or of statisticalrobustness. A conclusionsimilar to barkbcctlc-caused tree moft lity (treeskilled by thosereached in thejanah forestswas reachedin bcctlcs after being woundedor stressedby lire). a tallgrassprairie ecosystem.where mitcs and Thereforc, thc ovcrall amount of CWD remain- collembolanswere tbund to be more numefous ing after fire, and its aft'ccton CWD-chewers,is in unbumedsites than bumed sitcs (Seastedt 198,1). likcly to bc site specificand dependenton the In contast, ho\\,ever. Lussenhop (1976). who also mount consumedby lire and the amount input worked in a prairie ecosystem.found that by live alter 1lre. months after a spring burn, greatcr numbersof

1,1,1 Niwa, Peck.and Torgcrsen microarthropodswcrc fbund in burnedsites than to root tips, and changesin soil tempenture and unbumed sites. This increasewas attdbuted to moisture. are sone of the factors th t may ac- an increaseiIl plant productivity after fire. count fbr this response.Soil microarthropoddi- Preliminary results from a replicated study versitywas higher in the unbumedsitcs. Ofseven comparingfall andspring underburning and un- familiesofspiders analyzed, fbur weremore abun burned checkson the Burns RangerDistrict, dant in unbumedsites while three familics were MalheurNational Forcst, OR, found that seven more numerousin burnedplots. Four of five com- speciesofroot-fecding bark beetleswere trapped mon ground bcetlc specieswere more abundant more frequentlyin buned than in unbumedplots in unbumedsites. Changes in fomging substrate, (Niwa andThies, unpublished data). Some ofthese prcy availability,or microclimatic conditionsaf- specicswcrc more abundantin thll burns,while terfire mayhaveinJluenced the abundance ofthese othe$ were most numerousin bums conducted organisms.There was no difTerencein the diver- in the spdng.Hllastes Ltter, a likely vectorof sity of either spidersor ground beetlesbetwecn black stain root diseasein pine, was most abun- bumed and unbumedareas. The relationbetween dant lbllowing fall fires. Therewas no difference abundanceof both micro- and macroarthropods possibly in the total abundanceof ground beetlescaught andtime sinceburning was weak. nasked b5 differenec:in fircintcnsities 'ite.. in pittlll traps bet\i'eenthe tall, spring, and un- betueen bumedcheck plots (Niwa andPeck. unpublished Thepossible effcct' of tirnberhlrrerting on data). The ground beetlespecies. Trnr:h_rpn.hls afihropod communities are wide ranging, from holnbergi- occured in extremely Io* numbers ellects on the soil and litter from mechanicalop- betbre burning, but was signillcantly higher in erations (sce below). to microclimatic changes fall-burned sites one year alter the 1lres. Z following the partial or completeremoval of the holmbergihas lully developedhind wings. ap- tree canopy,to the addition of organic matter in- pearsto bc an cxtrcmel), opportunistic itnd per- put to the forcstfloor Fellin ( | 9ll0a, 1980b) found hapsscavenging omnivore. adults are often found clear-cuttingto be a morc disruptivepractice than in high abundance,and it is probablythe most shelte$ood cutting 1o most soil- and lifter-dwelling curytopic of the Nofih American Trachrpachus arthropoLlgrrrup.. Tn u studl of spidersuccession pionccr afterclear-cutting in westemOregon. visual-pursuit species-all traitsofa species.Pittall trap "sit- capturcsoftotal spidcrswere reduced in fall- and hunting spidersdominated clearcuts, while spring-bumedareas comparcd to unbumedcheck and-wait" microweb and trapdoorspiders domi- plots (Niwa and Peck. unpublisheddaLa). Of thc natedmaturc lorest. (Mcl\er cr al. lqq2).The ten spider families analyzed,only wolf spiders reestablishmentof common forest specieswas shou,ed a difference between ffeatments.with nore rapid on wetter sites.Microcnvironmental abundancereduced in boti of the bumed treat- condirir\nsand the arril.rbilitl and 'pecies com ments comparedto controls. Spring buming co- position of prey were the most likely factors in- incidcdwith thcreproductive period of thedomi- fl uencingspider species composition. Following nant$olf spiderspecies, which may haveresulted clear-cuttingin a borcalforest in westernCanada, ground youngest in highlerel. oi directmortalitl. Buming in ei beetleswere most abundant in thc sitcsand in mature moist (Neimela ther seasonmay haveinitiated changesin habitat standson soil et al. 1993).Species richness was higherin re- suitabilit)'and prey availabilitythat \\"ereless genenting sitesthan in matureforests. The abun- irdvantageousfbr this family. danceof fbrest geleralist specieswas dramati- A retrospectivestudy was conductcdon the cally rcducedfollowing clear-cufting, while species AshlandRanger District. Rogue River National of open habitat appearedor incrcasedin abun- Forest.OR. assessingarthropod response in pre- dance.and mature forest speciesdisappeared or scribed burns of dilTerentages, and comparing decreasedin abundancc.lna landscape-scalestudy bumed to adiacenturburned check areas(Niwa of thinningin Douglas-firforests in westemOr- and Peck, unpublisheddata). The abundanceof egon,Madson (l998) foundno statisticaldiffer- microarthropodswas reducedin the bumed ?Lr- cnccsin macroafthropodscollected inpitfall traps eas,particularly thoseresiding in the litter, rvith or in microarthropodsextracted from soil and lit- lessereffects detectedin the soil layers. Direct ter samplesamong late successional,pole-sizcd nortality. a reduction in food rcsourccs,damage (80yrs old) andthinned (9-23 yrs in age)stands.

Soil. Litter, and CoarseWoody Debris 145 Ho$ ever, within sites a trcnd toward trcatmcnt with striltum and taxonomic group. ln general. dillcrcnccs was ofien seen. managementpracticcs such as burning and corn Compactionof soilshas implications for the pactionappearto have greateleffect on aflhropods soilfood u,ebas wellas lbr othcrfunctional groups. inhabiting the fofest floor than on thosethat ]-e- Compactionmay occuras a resultof largcherbi- .idc in the\oil. Liuer.lnJJult cotnmunitie.are vore grazing or the useof machineryduring har- alteredby managementactions that directly crush \e.ling .rnJother rtand managenrcnl cctr\ilic\. or mix theselayers; in addition,they are indi- Soil contpactionreduces pore size.resulting in recll)afiecled br .uhr.quent,.hange.in \cgelr loss ol'habitat itnd a reduction in nuffient reten tion. nricroclimate.and other ecologicalfactors. tion,and it changesthc microbialand nematode The effects of surfacetreatments tend to be less conrmunitiesof the soil food rveb. directly af- severewithin the soil, and organisnspossibly lectingnun icnt clcling asrvell as influencing the retrcat to lo$'er depthskr avoid adverseaffects. food availablelbrgrazing rnicroafthropods. A srudy Thc abundanceof litter-dwellingmicroafi hropods on the La GrandcRanger District of theWallowa appearsto be reduccdby direct mortality attdb- Whitman Nationtrl Forest, OR, compared utable to managementactions. while litter macroarlhropods microarthropod abundanccsin fbur soil distur- ottendemonstate shifts in com- bance classes(conpacted. lightly displaced. munlty stmcturerespondin-s to habitatchanges. heavilydisplaced. and undisturbed) and two lit- The study of soil. ltter, and CWD anhropods ter disturbanceclasscs (compacted and undis- is truly in its infancy, espccially work that can turbed)following mecharricalharvesting (Niva cfllctively be relatedto eastemOrcgon and Wash- and Peck. unpublisheddata). The levcls of corn- lngtonecosystems. Thrcsholds required lbr healthv pactionand displacement experienced in the study ecosystemlunction and predictivc and decision- did not appear to have an effect on soil \upF,n lool).lhrt incluLlelhe.e cornponcnr: in microanhropodabundance: however, variability relation to disturbancesarc not availrble. Future wasextremely high bctween samples making the rc.eirr(h\ht\uld in\ e:lig.tlemanilge ment prrcli(c\ detectionofdiffercnces difficult. Compactionhad relevantto thesehabitats. including various tuel a negative etlect on the abundance of treatments,subsoiling, tree harvest, and wildfire. microarthropodsin the ljtter layer. Reductionin The tiequency of managemenlcntries and sea- thc number of litter nicroi:rthropods may have sonaltiming ofthese actions are also of conccm. resullcdfrom direct mortality.a reductionin food While paststudies havc addressed anhropod abun- availability, a loss of rcf'ugiafiom predators,or danceand diversity. none have successfully linked possiblychanges in microclimaticconditions. djslurbrneceffecls on irflhrrrn('J( ummu nitie5 lo Funher studiesare necessaryto determinehow changesin ecosysteorfunction. There is a need loDgit takesthis microarthropodfauna to recover. lbr erperimentalwor k thatu ould,Jeterrnine quan titalivc rclationsbetween fihropods andprcccsses Mechanicalsubsoiling is sometimesused to suchas decomposition. nutrient cvcling, and pre- rcduccthc impactsof cornpaction.However this dation.The scaleof studies,both tcmporalJyand practicc,as wcll as otheroperations that physi spaliallyshould also be considered:long-tem and/ callymix thelitter and soil. may break roots and or broad-scalestudies are nccdcd to guide land disturb fungal mats, and potentially aft'cct*ater allocationand planning effbrts. Finally, the identi- andthermal relations in this criticalstratum. ficationofindicator species or thedcvelopment Thc literature concerningdisturbance effects ofsurogatehabitat measures sucb as plant com- on soil. litter. and CWD-dwelling arthropodsin munitiesor CWD could be hclpful shortcuts forcstcdecosystems, and in particularin eastside for continuedmonitoring of arthropodfauna conilcrcommunities, is sparse.and results vary and function.

LiteratureCited Behan.V.M.. and S.B.Hill. 1978.FeedinS habirs and sporc dispersaloforibalid nies h lhe NonhAmerican arctic. Beaudr!. S.. t-.C. Duchcsnc.and B. Core. 1997. Shorl-tern Revie$ ofthe Bcologyand Biolog,"- of Soilsl5:.197- efl;cts of three fbrestry practiceson carabid alsclr 516. blagesin ajackpinc iorcst.Canardi.rn Joumal of Foresl Berthet.P 1967.The metaboljcacti!ily ol oribatidmiies Research2l:2065-2011. (Acafinx) in different forcst flools. Prges 709-7251/1 l,+6 Ni\\.a, Peck. and Torgersen K. Pcrru\cwicz(editor), Secondaf) Producti!it! of Harrnon.l!1.E.. J.F. Fnnklir, FJ. Srrn\on, P Solli.s. S.V Tcrcslriil Ecosystelns.\\'rrsaw Edirion. Chapman and Gregor!.J.D. Laltin. N.H.,{ndelson, S.P Cline. N.C. I{all. London. Aumxn J.R. Sedell.Cl.W. I-icnk.remper K. Cfomack, Bull. E.l-.. lR Torgelser. and T.L. $tftZ. /, /rr!r r. I he im Jr.. and K.W Cummin\. 1986.Ecolog,"- ol co. se portanc. ol vcgetadon.irsects. and neonrteungulates roody dcbri\ ir rcmperateecosystems. Pages lll in black bcar dier in northeasternOfegon. Nofthlr'est 302 1, A. \4acFadlcn and E.D. Ford (editut. Re Scicnce. cent Adv.rncesin Ecological Rc\carch. !ol. 15.Acr- Coleman.D.C.,.rnd D.A. Crossle,v.Jr. 1996.Fundancntals denic Pfess SanDiego. Califomia. ol Soil Ecologv.Acadc ic Prcss.Srn Diego.Culi Hrnis, D.L., and\\'.H. Whircomb. 197,1.f{abilal relarionship and seasonalrbundance offour spccicsoltr.rrllnrr Coleman.D.C.. E.P Odum.and D.A. Crossle).Jf. 1991.Soil (Colcoptel'a:C:uabidae). Coleopterisrs Uullclin l5:67 blology.soilccolog) and globrl change.Bknogy and 72. Ferrilitvof Soil\ l,lil0.+ 111. Hengeveld.R. 1980. Polyphag]'.oligophag,"- and lbod spe- Coleman.ll.C.. C.P Rcid.and Cl.\: Cole. 1983.Biologic.rl cirlization in ground beetles(Coleoptcra. Carabidae). strategicsof nl(ricnt crclirg in soil sysrems.Ad!anced NclhcrlandsJoumal Zoobgr 30:5 6,1- 5 8,1. F-cologicalRcscrrch 13: i'55. Ho llida\'. N.J. | 9 8,1.Carabid beetles (C(teoptera: Carabidac ) Ednonds.R.L.. rnd A. Eglitis. 1989.The role of lhc Dou lionr a bumcd spruceibrest (P,.€d spp.). Canadjau g1.r\-fif beetlemd $ood borcr\ in lhc dccomposition EnlonrologistI 16:919 922. of and nutrient releascfrorn Douglas lir logs. CrLna- Kitchell.J.Fl. R.V. O'Ncill. D. \l,'ebb.G.W Gallepp.S.N{. dianJourrral of Forcn Rcscarch19:851 859. Baltell.J.Fl Koonce. and B.S.Ausnus. 1979.Con- Fellin.D.G. 1980n.Eltect of sjl!'iculturalpr,rctices. residue suner rcgul:rtronof nutfientc) cll ng. BioScicncc29:28 utilizatior. and prescribcd firc on solne linesi llool :ll' .rnhrcpods.Page\ 287 316 /l1 En\ironmental Conse- Lussenhop,J. 1976.Soil ardrropodrcsponse to praifie bufn- quences of li bcr tlarlcning in Rocky N,lountain ing.Ecology 57:88-98. CloniicrousForcsts. USDA ForestSenice General Madson. S.L. 1998. Correlation between structurll hetero- Tcchrical Report INT-9{1.Intemountain Forest and gereil) aDd afihfopod biodiversit,viimplic.tioDs lbf R.rngeExperinrent Station. Ogden. Llah. managenentofPacific Nofih\\'cst forcsts.M.S. The- .i' Fellin.D.G. 1980b.Populations ofso lc lbrcnlirler.hunms. Or

Soil, Litter, and CoarseWoodv Debris 111 NlouklerB.C., and D.E. Reichle.1972. Significance of spi- Seastedt.T.R.. M.V Redd]'.and S.P Clinc. 1989.Micro der predation ir the energy dr-nanics of fbrest-floof afthfopods in decaying wood fronr temperatcconjl' a(hropod conlmuniric\. Ecological Monographs erousand deciduous fbresrs. Pedobiologia ll:69-?7. 12:.171-.198. Shaq,.C.H..ll. t-undkrisl.A. Molden](e.andJ.R. Boyle. 1991. Neum.rnn.F.G. 1991. Responsesof iitter afihropod to The felationshipsofsoiltaunato long lerm forcslpro major naruralor arriilcial ecologicaldisrurbances ducti\ ity in iemperateand borcal ecos] stems: pruesses in nrountainash ibrcst. Australian Journal ol Ecol andresettrch straiegies. Pages 39-77 /, $'.J. Dlck and ogy l6:l9 32. Cl.A. Nlees (edilors). Longrern Field Trial\ to As- Ne$'.T.lt. 1995.An lntroductionto lnverlebratcConscr scs\ En\ion lenlal lnpacr oi Harvesting.Proceed- \'ation tsiologv.Orford Uriversil_vPress. Oxford. ings IEA/BE T6/A6 Workshop:February 1990r I 9.1p. Florida. USA. IEA/BE T6/A6 Rcpoi No. 5. Newell. K. 198,ta.hrleraction betweent$o decomposerba- Springett,J.A. 1916.The eft-ectof frescribedburning on sidiomvcclcs and a collcmbolan undcr silka sprucc: rhesoil faunaaDd on litter decoDpositionin \Vest- distribution.abundance and selectivegrazjng. Soil crn Auslralianlorcsls. Aus[alian JournalofEcol- Biologyand Biochemistry 16:22'7 -233. ogv 1:77El. qid qeerl.. Ne$ell. K. 198'1b.Irreraciion betweent$o decoDrposerbr- ThelF,H.I' la--. C,-. -rd'r.r-.n\ unnrlnl sidiomycetesand a colleDrbolanunder sitkr spmce: Springer-Verlag.tserlin. grazing and its potential eftects on lungal distribu- Thoma\, J.W. (editor). 1979. Wildlife habitatsin anagcd lion and lilter decomposilion.Soil Biology and Bio' fbrests-the Blue l\,lountainsof Oregon and Whsh chcminn l6:215 239. ington. LrSDA ForestSer!ice Agriculture Handbook Niemela. J., D. Langor and J.R. Spence. 1993. Bffects of \o. 551.Washinglon. D.C. 512 p. clear cut harvestingon bore. ground-beetleassem- Torgersen.T.R.. and E.L. Bull. 1995. Down logs as habilat blagcs(Coleoptcra:Carabidac)in $cnc Canrda. 1brlbrestdwellirg ants the pfimar) pre),oftileated ConservatjonBiology 7:551 56l. $oodpecken in notheastem Oregon.Nonhlvest Sci- Niwa. C.G.. R.E. Sandquist.R. Cranford. T.J. Frcst. cncc 69:29,1303. T. Gris!\old.P Hanmond.E. lnghan. S.Jamcs. E.J. Torgcrscn.T.R.. R.R. \,lason.and R.W Campbell.1990. Preda- Johanne\,J. Johnson.WP Kemp.J. LaUontc,J.l). tion by bifds and antson two forestinscct pcns in |hc Lattin. J. Mclver. J. N{cMillin. A.l\,loldenke.J. ivloser. Pacilic Nonhwest.Studies in Avian B idogy I 3: I :l- I 9. 'Iorgersen. D. Ross.T' Schow.rlterV. Tepedino,andM.R.Wagner T.R.. J.W Thonras.R.R. Mason.and D. VanHorn. 2001. lnvcrtcbracs of lhc Columbia Rivcl basin as 1981.Avian predat(rs of Douglas-fir tussock . sessmentarea. USDA Forest Serrice GeneralTech O r8r"id p ! eud ot s u satd lMcDunnough). (: nical Repoft PN\\LGTR-512. Pacific Nofihwest Re- Lynrantriidae)in soulhwcslcmOregon.Environnen- se:rch Station.Porlland. Oregon. tal Entomology13: l0l 8 1022. Richardson.R J.. andN.J. Holliday. I 982. Occurence of cJ a- Vossbrinck.C.R.. D.C. Coleman. and lA. Woolle). 1979. bid beetles(Coleopre : Carabidae)in r borerl lbrest Abiotic and bioiic factorsin littcr dccomposilionin a danragcdb,,- firc. ClanadianEnonologisl 11,1:50951:1. semiaridgrasdand. Ecology 60:265 271. Santos.PI-.. J. Phillips.and w.C. whitford. l9El. Thc rolc W'allwork, J.A. 1972. Distribution patternsand populalion of mites and nemalodesin earlv stagesofburned lit dlmmics of the microanhropodsof a deseri soil ;n ief decompositionin a desef. Ecolog) 62:664-669. southcrnCalifornia. Joumal oi Ecolog! Schowaltcr.lD.. 8.,{. Cald$e11.S.E. Crrpenter R.P Grilliths. ,ll:291-310. M.E. Harmon.E.R. lngham.R.C. Kelscy.J.D. Lat Wallwork, J.A. 1983.Oribatids in forest ecosvstems.Annual tin. andA. R. Moldenke. I 992. I)econrpositionof fallcn Revie$ of Entomology28:109- 130. treesieffecN of initial conditionsand helerotroph colo Wickman. B.E. 1977. Observetionson spider predation nizationrates. Page\ 173-383 ,r K.P Singhand J.S. of carly insur larvaeof Douglas-fir tussockmorh. Singh (editors), Tropical Ecos,vstems:Ecology and Or{ i a ps( udots u sdta (McDunnough) (Lepidoptera: Managenent. wiley EasternLrd., New Dehli.India. L!nranlriidac).Pan Pacilic Entomologisl5l:.16. Scaned!.T.R. 198:1.Thc rolc ol microarrhropodsin decom Zhong, H., and T.D- Schowalter 1989.Conilcr bole uliliza, positionand mineralizationprocesses. Annual Review lion b) wood-boringbeetles in westenrOrcgon. of Entolnolog) 29:25-:16. CanandianJoumal ol Forcn ResearchI9:9.13-9,17.

Note

Thi\ specialissue of,\br//iner/ S.ri?r.e is a set ofpapers re vie*ing the stateof knowledge about disturbanceprocesscs in easternOregon and Washington. relaied management prac- liccs. and cliccts on ke) managementissues.

148 Niwa, Peck.and Torgersen