Comparative responses of spider and carabid beetle assemblages along an urban-rural boundary gradient

2011·6.6 MB·English

by  Marion Varet

2011.TheJournalofArachnology39:236-243
Comparativeresponsesofspider andcarabidbeetleassemblages along anurban-ruralboundarygradient
MarionVaret: Universitede Rennes 1, UMR CNRS 6553, 263 AvenueduGeneral Leclerc, CS 74205, 35042 Rennes
Cedex, France. E-mail: [email protected]
JulienPetillon: URU420-UniversitedeRennes 1,UMR7204-MuseumNationald’HistoireNational,263Avenuedu
General Leclerc, CS 74205, 35042 RennesCedex, France
Fran^oiseBurel: Universitede Rennes 1, UMR CNRS6553, 263 AvenueduGeneral Leclerc, CS 74205, 35042 Rennes
Cedex, France
Abstract. The urbanization process is the motor ofdeep environmental changes at both local and landscape levels.
Althoughmoreandmorestudiesareinvestigatingtheecologicalconsequencesofurbanization,onlyafewhavestudied
small-scaleresponsesofbiodiversityto urban-ruralboundarygradients,andevenfewerhavecompareddifferentmodel
groupssynchronically. Inthisstudy,wecomparedtheresponsesoftwoinvertebrategroupsoftenusedasbioindicators,
spiders and carabid beetles, along small-scale boundaries (around 1 km). The following parameters were estimated:
assemblage composition, species richness, and activity-densities overall and per life history trait (habitat preference,
dispersalabilitiesforcarabidbeetlesandhuntingguildsforspiders).Thefielddatawerecollectedin2009usingpitfalltraps
setrandomlyinhedgerowswithinurban,boundaryandruralzones(30trapsintotal).924adultspidersbelongingto78
specieswerecollected, whereasthe 330capturedcarabid beetlesbelonged to25 species. Wefound noevidenceofany
significantchangeincarabidbeetleactivity-density(overallandformostlifehistorytraits)orinspeciesrichnessalongthe
urban-ruralgradient.Conversely,therewasasignificantchangeinspideractivity-density,bothperhabitatpreferenceand
perhuntingguild. Wealsofoundaprogressivechangeincommunitycompositionforspiders. Ourresultssuggestthat
studyingdifferentmodelgroupscanprovidecomplementaryinformationabouturbanization.
Keywords: Hedgerow,urbanization,habitatpreference,trophicguild,dispersalabilities,Araneae,Carabidae
During the last decades the urban population has greatly city to the rural areas, but it is not yet clear whether the
increased, creatingintensiveurban areasandencroachingon changes are progressive along this gradient or ifsome sharp
adjacent rural areas (Douglas 1992; Fenger 1999; Weber transitions occur between those two highly contrasted
2003). Urbanization is defined as the installation process of habitats.Transitionzonesbetweenecosystems(e.g.,ecotones)
anthropogenic structures (e.g., buildings, roads) in existing may control the flow of energy, material and organisms
naturalorfarmingareas,inordertosatisfyhumanpopulation betweenecosystems. The functioningoftheboundaryisalso
requirements(Crocietal. 2008). Accordingtothisdefinition, oneofthemechanismsthatmayexplainbiodiversitypatterns
theurbanizationprocessisthemotorofadeepmodificationin (Di Castri & Hansen 1992). Most of the previous work
theenvironment. Urbanizationaffectsenergyflows,biochem- hypothesized, for example, exchanges between rural and
ical cycles, climateconditions, hydrology and soil properties urban areas, rural areas being sources ofindividuals able to
(Breuste et al. 1998; Bakeret al. 2002). This important land colonizethecity.Theaimofthepresentstudyistoinvestigate
use change has a strong impact on biodiversity, and whether and how an urban-rural boundary will affect two
progressively more studies are examining the impact of groupsofarthropodsinasinglehabitattype(hedgerows)and
urbanization. Currently, the main ecological questions are over a short distance (around 1 km). Spiders and carabid
howspeciescopewith the urban environment, pollution and beetleswereselectedasmodelgroupsbecausetheyareknown
the fragmentation of “natural habitats”, and how this to react strongly to changes in microhabitat conditions and
biodiversity is linked to the adjacent rural environment. thereforeareoftenusedasbioindicators(Marcetal. 1999;Bell
Recent studies indicate that biodiversity is lower in urban etal.2001;Luffetal. 1992;Rainio&Niemela2003;Pearce&
environmentsthaninagricultural landscapes(Niemela2009), Venier2006).
with a decrease in both species richness and abundance in In our research we tested the following hypotheses: 1)
urbanareas(Blair 1996, 1999;Clarketal.2007;Clergeauetal. AccordingtotheconclusionsofAlaruikkaetal.(2002)spider
1998; Denys & Schmidt 1998; Lehvavirta et al. 2006; and carabid beetle assemblages in urban areasdiffer in their
McKinney 2002; Pacheco & Vasconcelos 2007; Sadler et al. responsestoanurban-ruralboundary.Spidersareexpectedto
2006;Yamaguchi2004).Onthisissue,themainbulkofrecent respond only slightly ornot at all to the boundary, whereas
research on invertebrateshasconcentratedoncarabidbeetles carabidbeetlesareexpectedtorespondstronglyandsuddenly
(Alaruikkaetal.2002;Niemelaetal.2002;Ishitanietal.2003; to the boundary. 2) The urban environment selects for
Gaublommeetal.2008;Niemela2009).Untilnow,onlyafew particular ecological traits (Blair 2001). In both groups,
studieshavefocusedonspiders(Alaruikkaetal.2002;Magura speciesfromopenhabitatsareexpectedtobemoreassociated
etal. 2010). with urban areas due to a more open, mineralized environ-
Most of the information published to this day has ment. As the urban environment is composed of a hostile
considered longgradients(several km)fromthecenterofthe matrix, individuals with high capacity for (long-distance)
236
VARETETAL.—SPIDERANDCARABIDBEETLEASSEMBLAGES 237
dispersal are generally favored (Thiele 1977); more macrop-
terous species of carabid beetles are therefore expected in
urban habitats. The dispersal of spiders was not estimated
since dispersal propensity is supposed to be a non-limiting
factor in displacement and settlement for most species (e.g.,
Bell et al. 2005). As litter and vegetation structures in
hedgerowsarelesscomplexin urbanhabitats(Frileux2008),
fewer web-building spiders and more cursorial spiders are
expectedthere(Uetz 1979).
METHODS
—
Studysitesandsamplingdesign. Thestudysitewaslocated
attheboundarybetweenurbanandagriculturalareasinPace
(48°09'00"N,01°46'00"W),amunicipalityof8600inhabitants
locatedwithintheconurbationofRennes(Brittany, France),
which comprises 205,000 inhabitants. Sampling points were
set in hedgerows, the main semi-natural structures in both
areas,atfivesites(withsixsamplingpointspersite), defined
according to their distance to the boundary: two in the city
(UI and U2, respectively 0-150 m and 150-300 m from the
boundary),oneontheboundary(E)andtwointheruralarea
(R1andR2,respectively250-4d0mand950-1150mfromthe
boundary) (Fig. 1). The percentage of asphalt cover was
calculated by GIS (Geographic Information System) in a
100 perimeteraroundeachsite,andthepercentageofplant
cover was visually assigned to classes (0-1%,1-5%, 5-25%,
25-50, 50-75%, 75-100%). Soil water content and tempera-
mtouofrie2s0twu0er9reeummsieentagesruarHeWdH.E2ei.gT(h.btotstiehmnesbsoyratD(ee5latccahm-sTidteeDeedpvu)ircicenosgnntLehtcedt.s,eudCmtamome-ra (BrFiitgtuanrye,1F.r—anLcoec).atUio2n(Ao)f,tUh!e(sAa),mpEli(n®g),sRit1es(Aa)ndantdraRps2(in )P.ace
bridge,UK).Thepercentageofasphaltcoverdecreasedalong
the urban-rural gradient, whereas the percentage of plant usingRoberts(1987,1995)andHeimer&Nentwig(1991).The
coverincreasedalongthesamegradient(Table 1).Hedgerows nomenclaturefollowsLiedroth(1992)forcarabidbeetlesand
weremostlyorientednorth/south,exceptthoselocatedatone Canard(2005)forspiders.
urbansite,whichwereorientedeast/west.Therewasnoeffect Catchesinpitfalltrapswerelinkedtotrappingdurationand
ofsites on other habitat characteristics (Table 1), indicating pitfall perimeter, in ordertocalculatean ‘activitytrapability
thatconditionswithinhedgerowsweresimilarinthisrespect. density’ (number of individuals per day and per meter:
Each sample point consisted of one pitfall trap (85mm Sunderland et al. 1995), further abbreviated as ‘activity-
diam.)coveredwithaplasticroofThepitfalltrapswerefilled density’. In orderto analyzethecommunity responses along
with preservation solution composed of50% monopropylee the gradient, we studied species richness and total and per
glycol 50% and 50% salt solution of 100 g/I (best fluid for ecological trait activity-densities, as well as the assemblage
collectingground-dwelling spiders: Schmidtetal. 2006). The composition(basedonspeciesactivity-density).
pitfall traps were emptied every two weeks for eight weeks Carabidbeetlesandspiderswereclassifiedintothreeclasses
betweenmidApril2009andmidJune2009—. ofhabitatpreferenceusingHanggietal.(1995),Harveyetal
Species identification and classification. Carabid beetles (2002), Luff(1998) and Bouget(2004): forest species(species
andspiderswerepreservedin 70%ethanolandstoredinthe predominantly found in forest areas), open habitat species
Universitycollection(Rennes, France). Adultcarabidbeetles (species which occur predominantly in open habitats), other
were identified using Jeannel (1941, 1942) and Trautner & (speciesoccurringinwethabitatsandgeneralistspecies).The
Geigenmiiller (1987), whereas adult spiders were identified dispersal abilities of carabid beetles were estimated by the
—
Table 1. Habitatcharacteristicsoffivesamplingsites(percentageminandmaxofclassesofherbaceouscover,mean{±SE)forlitterdepth,
temperatureandmoisture).
U2 Ul B R1 R2
AHsepdhgaelrtocwoveexrpo(s%it)ion N-NE4/8S-SW E50m N12/.S5 N-NE/4S-SW N0/.5S
Herbaceouscover(%) 1-5 5-25 25-50 25-50 25-50
Litterdepth(cm) 0.83 ± 0.31 1.83 ± 0,56 1.08 ±0.30 2.33 ±0.56 1.25 ± 0.34
Temperature(°C) 14.57 ± 0.45 13.61 ± 1.07 12.97 ±0.18 14.28 ±0.65 15.01 ± 0.67
Moisture(%) 15.90 ± 1.19 14.21 ±0.48 il.93 ± 1.1 13.19 ± 1.55 12.45 ± 2.04
238 THEJOURNALOFARACHNOLOGY
developmentofwings(e.g.,Hendrickxetal.2007),andspecies significantdifferencesbetweensites. Thespeciesrichnessand
were classified as macropterous, apterous or dimorphic, in activity-density offorest species and web builders were not
aalc.co(2r0d0a8n)c.eSwpiitdherrsesweearrechclbayssLiifineddroatchco(r1d9i9n2g)atondthDeeirsehnudnetrinegt Fsi/g,n4if=ican0t.l7y3,difPfer=ent0b.e5t7w8eeanndsiteFs/j(F/=4 =0.108.,66,PP== 00..692456;,
habits(Uetzetal. 1999):webbuilders,ambushersandground respectively), but therewasasignificanteffectofsitesonthe
runSnteatriss.ticalanalysis.—Inordertoanalyzepatternsofspecies 0ac.t0i0v5i;tyF-idge.ns4iat)i,esamobfuospheenr-sha(bFi/t.^at=sp4e.c1i9e,sP(F=/40.=0094;.8F8i,g.P4b=)
compositionalongtheurban-rural boundarygradient, multi- andgroundrunners(F/4 = 6.06, P<0.001; Fig.4c).
variate analyses on activity-density of all species were Forcarabid beetles, siteshadno significanteffectonmost
performed using the software CANOCO (Ter Braak & explanatoryvariablestested(speciesrichness:Fjj= 1.24,P=
Smilauer2002).Thechoicebetweenlinear(PrincipalCompo- 0.321; total activity-density: F/4 = 1.93, P = 0.14; activity-
nent Analysis: PCA)orunimodal (CorrespondenceAnalysis: densitiesofdimorphicandmacropterousspecies:F,4 = 0.50,
gsCrpAao)dnideaennntacleypsrAeensvaildoyeuspsilesy)n.dreedaloinzedthewiltehngDthCvAalu(eDsetorfetnhdeedfirCstorarxei-s dPPen==sit00i..e07s934o8;faFfno,r,d4es=Ft/,1^o.p4=e8,n2P.a2n9=d,0oP.t2h=3e7r0ah.an0b8di7t,Fa/tr,4essp=peecc2it.ei1sv:6e,lFyPi;4=ac—t0i.2v1.i02t34y,,-
In orderto testdifferences in species richness and density- respectively).Therewasasignificanteffectofsitesonlyonthe
GactLivMitywi(ttohtaqluaasnid-Ppoeirsseocnolodgiisctarlibturtaiiotn) bweatswepeenrftohermfeidveussitiensg, abcuttiviptoys-td-enhsoictytoesftsaptdeirdousnostpecrieevsea(lF/s4ig=nif2i.c7a8n,tPdi—ffe0r.e0n4c8)e,s
data from the individual traps (Vincent & Haworth 1983; betweensites.
O’Hara & Kotz 2010). When GLM revealed a significant
DISCUSSION
effect ofsite factor, Tukey’s post-hoc tests with Bonferroni
correction formultiplecomparisonswere performedbetween Contrary to carabid beetles, the composition of spider
mean parameters. The resulting data were analysed with R assemblages intheboundarywasintermediatebetweenthose
software(R DevelopmentCoreTeam2009). from urban and rural habitats. Characteristic species for
RESULTS urbanhabitatswereEnoplognathathoracica(Hahn 1833),Tiso
— vagans(Blackwall 1834)and Troxochrusscabriculus(Westring
Descriptionofthefauna. Intotal,924spidersof78species 1851)and,forruralhabitats,P. lugubris,T.picta,D. erythrina
representing15 families were collected, among which Lycosi- and P. saltans. In addition, changes in activity-density were
dae were dominant (51% of all individuals), followed by either null, or progressive, indicating a general non-sharp
Linyphiidae (14.5%); Thomisidae (5.9%); Dysderidae (4.9%) response ofspider assemblages to the boundary. That result
and Gnaphosidae (3.9%). Individuals from five species, was mainly due to species with low to medium activity-
Pardosa prativaga (Koch 1870), Pardosa amentata (Clerck densities,whereasdominantspecies(i.e.,A.pulverulentata,P.
1757),Alopecosapuherulenta(Clerck 1757), Pardosalugubris amentataand P. prativaga) weredistributed along thewhole
(Walckenaer 1802), and Ozyptila praticola (Koch 1837), urban-rural transect. The latter species are all widely
accountedformorethan40%ofallcatches. distributedin Europeand occurinawidevarietyofhabitats
In total, 330individuals ofcarabid beetlesbelongingto 24 (Harveyetal. 2002; LePeru2007).
species and 15 genera were collected. Three species, Nebria This progressive change between urban and rural habitats
brevicollis,PterosticuscupreusandNotiophilusquadripuncatus, was also observed in relation to habitat preferences. The
accountedformorethan 50%ofallcatches. — activity-densities of species from open habitats increased
Changesinspeciesassemblagealongthegradient. Axis 1 of smoothly from urban to rural habitats. That result is quite
thePCAonspiderassemblages(Fig. 2)represented24.6%of different from previous studies (and from our expectation),
inertia, and Axis 2 represented 11.0% of inertia. Axis 2 whichshowedthatspeciesfromopenhabitatswereassociated
segregated urban sites from rural ones; the boundary traps withurbanareas,whereasforestspeciesweremorefrequently
werelocatedbetweenthosefromurbanandruralsites. Rural found in rural habitats (e.g., Magura et al. 2004). Yet, it is
trapswerecharacterizedbyP. lugubris, TegenariapictaSimon importanttonotethatmostpreviousstudieswerecarriedout
1870, Dysdera erythrina (Walckenaer 1802) and Pardosa in woodlands, not in hedgerows, as was the case here. No
saltansTopfer-Hofmann 2000. responsewasfoundfromtheweb-builderguild, butthatcan
Axis 1 of CA on carabid beetle assemblages (Fig. 3) beeasilyexplainedbythelackofefficiencyofpitfalltrapping
represented 15.9% of inertia, and Axis 2 13.0% of inertia. for that guild (e.g. Churchill 1993). The patterns ofhunter
Boundarysiteswereincludedinenveloperuralgroup. Axis 1 guilds(ambushersandgroundrunners)alongthegradientdo
segregated urban traps from rural-boundary ones. Urban notespeciallysupporttheviewofaprogressiveresponse, but
traps were mainly characterized by N. brevicollis, Badister insteadpresent,asexpected,aloweractivity-densityinurban
bipustulatus and Asaphidion stierlini, whereas boundary and habitats. That general negative impact ofurbanization is in
ruraltrapswerecharacterizedby Carabusintricatus,Harpalus accordancewithmoststudiescarriedoutalong(long)urban-
tardusandAgonummoestum. rural transects (Denys & Schmidt 1998; Blair 1999; Yama-
theChgarnadgieesnt.i—nTshpeerceieswasdenasistiygniafnicdantspeefcfieecst orficshinteesssonalotnhge galu.ch2i00270;04P;acLheehcvoavi&rtVaasetcoanl.ce2l0o0s6;20S0a7d)l,erbeuttala.pp2e0a06r;sCmloarrekient
total activity-density of spiders and the activity-density of contradictiontothefewstudiesspecificallyfocusedonspiders
“other habitat” species (F14 = 4.90, P = 0.005 and Fu = alonglarge-scaleurban-ruralgradients(Alaruikkaetal.2002;
4.45.P=0.007,respectively),butpost-hoctestsdidnotreveal Maguraetal. 2010).
^
VARETETAL.—SPIDERANDCARABIDBEETLEASSEMBLAGES 239
—
Figure 2. OrdinationdiagramofthefirsttwoaxesofPrincipalComponentAnalysisfor75spiderspecies(asterisk). Forprojection,the
sTpheecieensvfeiltorpaensge(sioslifdrloimne1s)%grtoou1p00u%r;ba4n3(sUp1e-cUie2s),arreurraelpr(eRs1e-ntRe2d)aanndd3b0ousnamdpalreys.(EA)bbsrietevsi.aStpieocnise:s:UA2gr(Ab)r,=U1Ag(rAo)e,cEa(b@r)u,nnRe1a((Bl)acaknwdalRl218(33));.
Alopu=Alopecosapulverulenta(Clerck1757);Arcle=Arctosaleopardus(Sundevall1833);Aulal=Auloniaalbimana(Waickenaer1805);Batgr
=Bathyphantesgracilis(Mackmll1841);Censy=Centromerussylvaticus(Blackwall1841);Cerbr= Ceratinellabrevipes(Westring1851);Cersc
= C.scabrosa(Cambridge 1871);Ciuco= ClubionacomtaKoch 1839;Dipla= Diplocephaluslatifrons(Cambridge 1863);Dippi =D.picinus
(Blackwall 1841); Drala = Drassodeslapidosus (Waickenaer 1802); Dyser = Dysderaerythrina (Waickenaer 1802); Enoth = Enoplognatha
thoracica(Hahn1833);Gonru=Gongylidiumrufipes(Linnaeus1758);Hahna=Hahnianava(Blackwall1841);Hapsl=Haplodrassussilvestris
(Blackwall 1833); Harho = Harpactea hombergi (Scopoli 1763); Micpu = Micariapulicaria (Sundevall 1831); Micvi = Microneta viaria
(Blackwall1841);Ozypr= Ozyptilapraticola(Koch1837);Ozysi= O.simplex(Cambridge1862);Paccl=PachygnathaclerckiSundevall1823;
Pacde = P. degeeri Sundevall 1829; Param = Pardosaamentata (Clerck 1757); Parho = P. hortensis (Thorell 1872); Parlu = P. lugubris
(Waickenaer1802);Parpo=P.proxirna(Koch1848);Parpr=P.prativaga(Koch 1870);Parpu=P.pullata(Clerck 1757);Parsa=P.saltans
Topfer-Hofmann2000; Phrmi = PhrurolithusminimusKoch 1839;Pocju = PocadknemisjunceaLocket&Miilidge 1953; Stegr = Steatoda
grossaKoch1838;Tegpi= TegenariapictaSimon1870;Tisva= Tisovagans(Blackwall1834);Troru= Trochosaruricola(deGeer1778);Trosc
= Troxochrusscabriculus(Westring1851);Trote= TrochosaterricolaThorell 1856;Xyscr=Xysticuscristatus(Clerck 1757);Zelap=Zelotes
apricorum(Koch 1876);Zelpe=Z.pedestris(Koch 1837);Zelsu= Z. subterraneus(Koch 1833);Zorsp = Zoraspinimana(Sundevall 1833).
For carabid beetles, neither classical parameters (density- Ganzhorn 2004). The length of the gradient studied here
activityandspeciesrichness)norparametersderivedfromlife wouldthusbetoo shortto reveal some responses ofcarabid
historytraitsvariedalongtheurban-ruralboundarygradient, beetles, known to react to changes in landscape structure
invalidating pro parte our expectations. That result is also (Bureletal. 1998). Changesinassemblagecompositionalong
contradictory to most studies that reveal a strong negative theurban-ruralboundarygradientasrevealedbymultivariate
impactofurbanization(e.g.,Alaruikkaetal.2002;Ishitaniet analysisincludedthediscriminationoftwogroups,associated
al. 2003). It must be stressed that our study originally with theurban and rural-boundary habitats. Urban habitats
investigated a very small-scale response (around 1 km), were dominated by N. brevicoHis, whose activity-densities
whereasmoststudiesindicatedsomechangesincarabidbeetle stronglydecreasedinruralhabitats.Thatspecieswasalready
species richness only after more than 3 km (e.g., Weller & known to occur mainly in urban areas (Weigmann 1982).
240 THEJOURNALOFARACHNOLOGY
—
Figure 3. Ordination diagram of the first two axes of Correspondence Analysis for 25 carabid species (asterisk) and 30 samples.
sAibtbesr.evSipaetciioesn:s:AUG2R(UA),=UA1g(oAn)u,mEd(o®r)s,alRis1((Pon)taopnpdidRa2n)(;A).GThMeOenv=elAo.pemso(essotliudml(inDeusf)tgsro18u1p2)u;rbAaSnF(LU1=-U2A)sa,prhuirdailon(RJ1la-vRi2p)esa(nLdinbnoauenudsar1y76(1E));
ASST = Asaphidionstierlini(Heyden 1880); BABI = Badisterbipustulatus(Fabricius 1792); BEDE = Benibidiondentelhmi(Thunberg 1787);
BELA = B. lampros(Herbst 1784); CAIN = Carabusintricatus Linnaeus 1761; DIGE =Diachronnisgermanus(Linnaeus 1758); HAAE =
Harpalusaffinis{F'dhricius1792);HARU=H.riibripes{DeGeer1774);HARF=H.nifipes(DeGeer1774);HATA=H. (Panzer1796);
LEFU=Leistusfilviharbis(Dejean 1826);LOPI =Loricerapilicornis(Fabricius1775);NEBR=Nebriabrevicollis(Fabricius1792);NBSA=
N.salinaFairmaire&Laboulbene1854;NOBI=Notiophilnshigiittatus(Fabricius1779);NOQU=N.quadripimctatus(Dejean1826);OOHE=
Oodes helopioides (Fabricius 1792); PTCU = Plerostichus cupreus (Linnaeus 1758); PTMA = P. madidus (Fabricius 1775); PTME = P.
incdaiuirius(Illiger 1798);PTNG = P. nigrita(Paykull 1790).
VARETETAL.—SPIDERANDCARABIDBEETLEASSEMBLAGES 241
sites
—
Figure 4. Meanactivity-density(±SE)ofspiderspersitealongtheurban-ruralboundarygradient,a)openhabitatspecies,b)ambushers,c)
groundrunners.Significantdifferencesareassignedbydifferentlettersabovebars.
Boundaryandruralhabitatswereconverselycharacterizedby As revealed by multivariate analyses, spider and carabid
C. intricatus, a forest species (e.g., Desender et al. 2008). beetleassemblagesexhibiteddifferenttypesofresponsesalong
Further studies should thus investigate the importance of anurban-rural boundarygradient. Spidersexhibitedarather
hedgerowconnectivityinforestspeciescolonization. progressive response, whereas it was almost null forcarabid
242 THEJOURNALOFARACHNOLOGY
beetles. This difference may be attributed to differences in wood «fe M.L. McKinney, eds.). Kluwer Academic Publisher,
dispersal abilities and in sensitivity to environmental factors, Norwell,Massachusetts.
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wbeietthlehsig(hPedtiislpleornsaeltaabl.ili2t0i0e8s)a.reItmhoarsebseenesnitsivheowtonltohcaatlhsapbeictiaets BretSuopsirtriee,ngNeaJ.rt,uVrHee.rllleaF,ge,lPadBreairmsl.einn.n & O. Ohlmann. 1998. Urban Ecology.
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gonrfuamdtibheeenrtt.wooIftgmcruaorsuatpbisfidnssatlucldyaiubegedhtsmtaraeynsdsaedltsotohasbtoemtahetetdcrioifb-fuvetareredynittnorgetsfhpaeocntlsooerwss ClaTbQruuakte,stemePnra.fsJnl.liy,aaJnn.sdpMce.MocauiRsesetseaeldurmih&ceh3anFt3e.hs:Ssl4.,a7Cn5dhg^ue8siw1pl..idd2e0srt0r7au.scstEeufmrfbee,lcatgsaeno.fdMurerbamarointiiyrs.astiUoorfnbtaohnne
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comparing several model groups synchronically, since their Small urban woodlands as biodiversity conservation hot-spot: a
srceaslpeonosfesteonsaitgiivivteyntporoceensvsi,romnamyendtiaflferf.actors, and thus their Denmmyuuslg,twiCo-.trat&xo{nHA.ratpeSpmcrihosmaiicadht.v.uLl1ga9an9rd8i.sscILan.ps)eecptElcocotoslmomagulynoin2tg3i:1ea1sn71ou-nr1b1ea8xn6p.egrriamdeinetnatl.
ACKNOWLEDGMENTS Oecologia 113:269-277.
We would like to thank Anne Treguier and Beatrice DesMe.ndJearc,obKs.,,JW..LaDmebkroencihntcsk,,MD..PMoalleest,,EL..SCtraesvseecnoe&urN,.MT.hyDsu.fr2e0n0e8,.
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PetAiYblesplenpotelnlli,e.esJd.2,c0EoA0cm.8om.lGuoenIgoinyrftgli9eue:ses7n,4c3iAe-n.7o5Cdf1ia.fnafbaeirroedtn,itcJ.sf-aaClc.tt-oLmreasfresouhvnress,ypsiJtd.eePm.rs.BaanBkdaksegircro&aunnFdd. YYsanmpreaialcgr,huknsFce.hsosi&f.,TEAToc..okly2Co0aog0ni4aac.ranlddI.nRCfe2lhs0uie0eb0naa.crecCShioptfiy1d,u9er:Jrb2aa0bpn9ia-ion2sd1ai6t-v.ie1ro.snAintoyanliyansnitcsodnoinfsetacrntitibuostnpieowcniiteihsn
RDfoervestlaotipsmtiecnatlcCoomrpeutTienag.m.R2F00o9u.ndRa:tiAonlfaonrguSatagteisatincdaleCnovmipruotnimnegn,t JthoeurnvaelgeotfatAironachstnroulcotgurye28a:n1d07t-h1e14.foliage orientation of hedges.
Vienna,Austria. ManuscriptreceivedI October2010, revised15February2011.