Moles and Mole Control on British Farms, Amenities and Gardens after Strychnine Withdrawal

26 Pages·2016·3.65 MB·English

animals
Article
Moles and Mole Control on British Farms, Amenities
and Gardens after Strychnine Withdrawal
SandraE.Baker*,StephenA.Ellwood,PaulJ.JohnsonandDavidW.Macdonald
TheWildlifeConservationResearchUnit,DepartmentofZoology,TheRecanatiKaplanCentre,
UniversityofOxford,TubneyHouse,AbingdonRoad,Tubney,AbingdonOX135QL,UK;
[email protected](S.A.E.);[email protected](P.J.J.);
[email protected](D.W.M.)
* Correspondence:[email protected];Tel.:[phone]
AcademicEditors:MarinavonKeyserlingk,KateLittin,TrudySharpandNgaioBeausoleil
Received:26February2016;Accepted:9May2016;Published:8June2016
SimpleSummary: MolesareburrowingmammalsthatareregardedaspestsinBritain,anduntil
2006theycouldlegallybekilledusingstrychninepoison. Whenstrychninewaswithdrawnthere
were fears that mole populations would increase. We surveyed farmers, amenity managers and
householders about moles and mole control on their land in 2007, post strychnine withdrawal.
Kill-trappingwasbyfarthepreferredcontrolmethodusedandcontrolmaybeusedmorethancan
bejustifiedbydamagelevelsortheeffectofcontrolondamage. Moletrapsareunregulated,unlike
mostotherspringtraps,andsomemightnotmeetcurrentwelfarestandards. Wefoundnoevidence
thatmoleactivityhadincreasedsincea1992surveyoffarms.
Abstract: MolesareconsideredpestsinBritain,butthisissuehasbeenlittlestudied. Lowerwelfare
standardshavebeentoleratedformolesthanformostothermanagedwildmammalspecies,asuse
ofboththecontroversialpoison,strychnine,andunregulatedtrapshavebeenpermitted. Strychnine
waswithdrawnin2006andtherewerefearsthatmolepopulationswouldincreaseasaresult. In
2007,weconductedacomprehensive,nationwidesurveyoflandmanagerperceptions,opinionsand
behaviourregardingmolesandmolecontrolonfarms,amenitiesanddomesticgardensinBritain.
Wesurveyed2150landmanagers(achievinga59%responserate)andground-truthed29responses.
Moles were reported to be present on most farms and amenities, and 13% of gardens, and were
more common in lighter soils. Where present, moles were usually considered pests, this being
morelikelyinWales,ScotlandandnorthernEngland,onlivestockandmixedfarms,andonlarge,
high-valueamenities,e.g.,racecoursesandgolfcourses. Molecontrolfollowedsimilarpatternsto
mole presence. More control may occur than is economically, and therefore potentially ethically,
justified.Controlshouldbemorecarefullyconsideredand,wherenecessary,moreeffectivelytargeted.
Kill-trappingwasthefavouredrecentandfuturemethodonfarmsandamenities,evenifstrychnine
wastobereintroduced; however, becausemoletrapsarecurrentlyunregulated, somemightnot
meet current welfare standards if tested. We found no evidence for an increase in moles since a
farmquestionnairesurveyconductedin1992;thiscouldhavewiderimplicationsforfuturewildlife
managementpolicychanges.
Keywords: European mole; Talpa europaea; farms; amenities; gardens; mole control; strychnine;
trapping;silage;questionnaire
1. Introduction
European moles (Talpa europaea) are solitary, fossorial insectivores. Each individual inhabits
its own system of underground feeding tunnels, in which it hunts soil invertebrates, principally
Animals2016,6,39;doi:10.3390/ani6060039 www.mdpi.com/journal/animals
Animals2016,6,39 2of26
earthworms[1,2].MolesaredistributedacrossmuchofEuropeandintoRussia[3],andarewidespread
throughoutBritainbutdonotoccurinIrelandoronmanyoftheBritishislands[1,2]. Molesproduce
conspicuousabove-groundsignsintheformofspoilheapsknownasmolehills. Moletunnellingand
molehillproductionareacauseofcomplaintamongfarmers,amenitymanagersandgardeners,and
molesarewidelyconsideredpests[4].
Reported mole/molehill damage on farms includes pollution of silage, coverage of
pasture, encouraging weed invasion and causing damage to plants, machinery and drainage
systems/watercourses[4,5]. Damagereportedonamenitiesandgardensisoftenmerelyaesthetic,
butmoleactivityonracecourses,grassairstripsandsportsfieldsmaypresentriskofinjurytopeople
andanimals[4,6]. Someaspectsoffarmers’experiencesandopinionsofmolesaspests,andofmole
managementconductedbyfarmers,havebeenstudiedinBritain[5]andScotland[7],butnosuch
researchhasbeencarriedoutwithamenitymanagersorhouseholders(domesticgardeners).
Inaquestionnairesurvey,conductedin1992,Atkinsonetal. (1994)[5]foundthat64%offarmers
perceivedmolesaspestsbutthatonly50%ofsurveyrespondentsmadeeffortstomanagethem;the
authorsconcludedthatthedamageattributedtomoleswasslightonmostfarms. Nodetaileddataare
availablefromtheScottishstudy[7]. Thecostsassociatedwithmoledamageandcontrolaredifficult
toassess,butestimatesforthetotalannualcosttofarminginBritainrangebetween£2.5millioninthe
late1980sandupto£5millionin1994[2,4]. Thesefiguresequatetoarangeof£5.6–7.8millionat2015
prices[8]. Toputthisinperspective,theannualcostofEuropeanbadger(Melesmeles)damagecaused
tocrops,orthroughburrowingorpredation,inEnglandandWaleswasestimatedtobesomewhere
between£21.5–41.5millionperannumin1997[9],equatingto£35–68millionin2015.
VariousmethodsareusedformanagingmolesandmolehillsinBritain,includingkill-trapping
(spring-trapping),gassingwithphosphine,live-trapping,shootingandultra-sonicdeterrents,aswell
asharrowingandrollingtoflattenmolehills. Nopoisonsorchemicalrepellentsarecurrentlyapproved
forusewithmoles. RenardineTM,aboneoil-basedrepellent[10],wasapproveduntil2005,whenthe
licensewaswithdrawnacrossEuropefollowingconcernsoverthetransmissionofBovineSpongiform
Encephalopathy(BSE)[11]. Strychnineisanalkaloidpoison. Actingthroughcompetitiveinhibition
of glycine (a neurotransmitter), strychnine allows unimpeded stimulation of motor neurons thus
causing the striated muscles to produce generalised rigidity and tetanic seizures [12]. Ultimately
thisleadstodeaththroughexhaustionorthroughasphyxiaarisingfromparalysisoftherespiratory
muscles. Strychninehasbeendescribedasdangerousandinhumane[5]andwasbannedforwildlife
managementundertheAnimals(Cruelpoisons)Regulationsof1963,andyetitscontinuedusewas
allowedonlywithmoles. Atkinsonetal.[5]suggestedthisexemptionwastoleratedbecause: (1)mole
damage was perceived to demand action; (2) strychnine was the only poison cost-effective on an
agriculturalscale(andnosuitablealternativewasavailable);(3)molesdiedundergroundwheretheir
painfuldeathscouldnotbeseen.
Forapesticidesuchasstrychninetobeusedlegally,notonlymustthepesticidenotbeillegalfor
theparticularpurpose,butthepesticidemustalsobeapprovedforthatuse(nowbytheChemicals
RegulationDirectorate[13]. Bytheearly1990s,thenumberofpermitsforstrychnineusewasbeing
reduced[5],andin2006strychnineapprovalforusewithmoleswaswithdrawn,aspartofanEU
pesticide review, when manufacturers failed to produce the necessary health and safety data [14].
Thisfollowedyearsofconcernaboutthehumanenessofstrychninepoisoning,thepotentialforits
misuse,andthesignificantcostsinvolvedinadministeringandpolicingitsuse[4,5,15]. Strychnine
alsopresentedthepotentialthreatofaccidentalprimaryorsecondarynon-targetpoisoningofwildlife
andcompanionanimals(see[15,16]). However,strychninewasconsideredtobethemostcost-effective
methodformanagingmolesonalargescale,althoughkill-trappingbyskilledoperatorsmaybebetter
forremovingsmallnumbersofmoles[4,5]. Strychnineisreportedtohaveoncebeenthemainmethod
of managing moles on British farms [7]; see also [4,5]. It has been suggested that, because of the
relativelylowcostofstrychninetreatment,moremolesmayhavebeenkilledthancouldhavebeen
Animals2016,6,39 3of26
justified[4]. Anditispossiblethat,ifthesehadnotbeenpoisoned,somemayhavediedanywayas
partofthenaturally“doomedsurplus”(seeErrington[17]).
Althoughstrychnineuseinmolecontrolwasalreadydecliningbeforeitwasbanned,in2004/2005
sufficient strychnine was sold in Britain to kill almost 800,000 moles [1] and 3000 users were
licensed[14]. Itwaspredictedthatthelossofstrychninewouldforceuserstoreconsiderthecosts
and benefits of managing moles using alternative methods, and that trapping would become the
primarymethodofmolemanagement,whileforsomemanagers,takingnoactionmaybecomethebest
choice[4,5]. Becauseofconcernthatnosuitablealternativemolemanagementmethodwasavailable,
itwassuggestedthatmolepopulationswouldincrease[4,18],anditwassubsequentlyclaimedthat
theyhad[19–21]. Althoughstrychnineapprovalwaswithdrawnin2006,thelegalexemptiontouseit
formolecontrolremains,soifstrychninewastobere-approvedinfuture,itwouldbecomelegalto
useitagain.
We conducted a comprehensive, nationwide questionnaire survey to examine land manager
perceptions, opinions and behaviour regarding moles and mole control on farms, amenities and
domesticgardensthroughoutBritain,andfactorsaffectingthese. Wesetouttocomparesomefarmer
responseswiththoseobtainedinAtkinsonetal.’s1992survey[5].Wealsoaimedtoestimatetheimpact,
ifany,ofstrychninewithdrawalonmolemanagement. Weconductedfieldsurveystoground-truth
a sample of questionnaire respondents for validation purposes. We found that where moles were
present,theywerecommonlyregardedaspests,andoftencontrolled. Ourresultsalsosuggestthat
morecontrolmaybeconductedthanisnecessaryandthatitmaybepoorlytargeted.Toourknowledge,
thisisthefirstpublishedsurveyofmolemanagementissuesonamenitiesanddomesticgardens,and
thelargestsurveyconductedtodateregardingmolesonfarmland.
2. MaterialsandMethods
ThisstudywasgrantedethicalapprovalbytheCentralUniversityResearchEthicsCommitteeat
theUniversityofOxford(approvalreferencewasSSD/CUREC1/07-003).
2.1. QuestionnaireSurvey
We designed a postal survey using Dillman’s Tailored Design Method [22] to optimise
surveyresponserate, includingmultiplecontactswithpotentialrespondents: (a)pre-noticeletter;
(b)questionnaireandcoveringletter;(c)thankyou/reminderpostcard;(d)replacementquestionnaire
tonon-responders. Weobtainedendorsementforthesurveyfrom:TheNationalFarmers’UnionWales,
TheNationalFarmers’UnionofScotland,TheBritishAssociationforShootingandConservation,The
GameConservancyTrust(nowtheGameandWildlifeConservationTrust),TheNationalTrust,The
RoyalHorticulturalSociety, TheRacecourseAssociation, TheAirportOperators’Association, and
TheBritishandInternationalGolfGreenkeepers’Association. Thesupportoftheseorganisationswas
mentionedinthecoveringletteraccompanyingquestionnairemailings.
Wedevisedseparatequestionnairesforfarmers,amenitymanagersandhouseholders,wherever
possible using similar-style questions across the three target groups to allow comparison of
responses. Questions covered: (a) Your farm/amenity/garden or allotment; (b) Moles on your
farm/amenity/garden or allotment; (c) Mole control on your farm/amenity/garden or allotment;
(d)Youropinionsaboutmolecontrol;(e)Strychninepoison;(f)Interestinparticipatinginafollow-up
study(ground-truthing). Questionnairesweremarkedwithindividualidentitynumbersandprinted
as A4 double-sided booklets. Questionnaires were piloted, and contacts and questionnaires were
translatedfromEnglishintoWelsh(recipientsinWalesreceivedversionsinbothlanguages). Weused
asystemdetailedunder“Recipientdatabaseabstraction”,inTextS1,torandomlyselect1204farmers,
551 amenity managers and 504 householders from across England, Scotland and Wales as survey
recipients. Contactswerepostedtothe2259recipientsasfollows: (1)21June2007pre-noticeletter
(allrecipients);(2)28June2007questionnaireandcoveringletter(allrecipients);(3)4July2007thank
you/reminderpostcard(allrecipients);(4)18July2007replacementquestionnaire(non-responders
Animals2016,6,39 4of26
only). FulldetailsofthequestionnairesurveymethodaregiveninTextS1andexamplesofthecontacts
andofthequestionnairearegiveninTextS2–S6.
2.2. QuestionnaireAnalysis
QuestionnairedatawerestoredinaMicrosoftAccessdatabaseandanalysedusingSASstatistical
software(TheSASInstitute,Cary,NC,USA)[23]. Weusedχ2and(whereexpectedcountswerelow)
Fisher’sExactteststoexaminerelationshipsamongcategoricalvariablesincontingencytables. We
usedFriedmanTeststoanalyserankedmonthlymoleactivityandrankedfeaturesofamolecontrol
method. Kruskal-Wallisχ2testswereusedtocomparecostsdataacrosscategoriesofrespondenttype.
2.3. Ground-TruthingSurvey
Weground-truthedaproportionofquestionnairerespondents, toassesstheaccuracyoftheir
reportsregardingthepresenceofmolesandthescaleofmoleactivityontheirland. Ground-truthing
tookplaceinspringandearlysummer2008and2009tocoincidewithperiodsofpeakmoleactivity
andcontrolasreportedinourquestionnairestudy,andbyAtkinsonetal.[5]. Weselectedpotential
participantsfromquestionnairerespondentswhoindicatedaninterestinparticipatinginfollow-up
work. Weattemptedtoidentifyarepresentativesampleof29questionnairerespondents,consistingof
17farmers(59%),eightamenitymanagers(28%)andfourhouseholders(14%),closelyreflectingthe
proportionsinwhichtheyrespondedtothequestionnaire(57%,24%,and19%). Thefarmsincluded
sevenmixed,sixlivestock,twoarable,andtwootherfarms,andtheamenitieswerethreeornamental
gardens,twogolfcourses,oneracecourse,oneancientmonumentandonepark.
Ground-truthingwasatwo-stageprocessconsistingofa30–60minsemi-structuredface-to-face
interview,followedbyafieldsurvey. Interviewswereintendedlargelytohelpusidentifysuitablesites
forground-truthingusingfieldsurvey. Duringtheinterviewparticipantswereaskedtoidentify,on
mapsandaerialphotographs,sixsites(fields/areas),ontheirland,whichhadatthattimethegreatest
(threesites)andleast(threesites)moleactivity. Wherearespondentreportednocurrentmoleactivity
onhisland,hewasaskedtonominatejustthree“noactivity”sites. Werecordedfurtherinformationfor
eachsiteincludingcurrentland-use(e.g.,pasture,cereal,mowngrass)andsiteaccesspoints.Following
eachinterview,weselectedtwositesforsurvey—oneeachidentifiedbytheparticipantashavinghigh
moleactivityandlowmoleactivity;weattemptedtobalancetherepresentationofdifferentfield/area
types,thenprioritisingsiteswiththemostandtheleastreportedmoleactivity. Whereaparticipant
nominatedonly“noactivity”sitesweselectedoneforsurvey. Ofthe29participants,23reportedboth
highandlowactivitysitesandsix(oneamenitymanager,onefarmerandfourhouseholders)reported
nocurrentmoleactivity;so,altogetherwesurveyed52sites. Fieldsurveyswereconductedwithina
fewdaysoftheinterview. Ateachsiteweimplementedasimplesurveystrategythatcouldbeadapted
todifferentfieldcircumstances;thisinvolvedconductingapproximately30full-pointsurveysateach
sitetorecordmolehillactivity. Fulldetailsoftheground-truthingsurveymethodaregiveninTextS7.
Duringtheground-truthinginterviewwealsoaskedparticipantswhethertheyfeltthatmole
activityhadincreased,decreasedorstayedthesameontheirlandovertheprevious5years.
2.4. Ground-TruthingAnalysis
Firstwecheckedwhetherlandmanagershadsuccessfullypredictedmolehillpresenceand/or
absence on their land. Then, using our survey data, we calculated molehill density per site and
comparedtheseestimateswithlandmanagers’reportedperceptionofrelativemolehillactivityon
theirnominatedsites. FurtherdetailsofdatamanipulationandanalysesaregiveninTextS8.
Animals2016,6,39 5of26
3. Results
3.1. QuestionnaireResponseRates
We included responses received up to the 11 November 2007. After excluding ineligible
recipients,therewere2150potentialrespondentscomprising1143farmers,526amenitymanagersand
481householders.Weachievedanoverallresponserateof59%(n=1265),withresponseratesdiffering
amongrespondenttypes(farmers63%(n=720),amenitymanagers58%(n=303),householders50%
(n=242)(χ2 =22.9,p<0.001,TableS1)),andregions,withmoreinScotlandandinthenorthand
(2)
south-west of England (χ2 = 12.3, p = 0.015, Figure S1). There was no evidence that respondent
(4)
typevariedwithregion(χ2 =6.7,p=0.574). Moreinformationonquestionnaireresponseratesis
(8)
availableinTextS9.
3.2. QuestionnaireResponses
3.2.1. FactorsAffectingMolePresenceandPestStatus
Weexaminedfactorsaffectingreportedhistoricmolepresence(whethertheyhadeverhadmoles
on their land) and mole pest status. Where “mole presence” and “pest status” are used here we
refer respectively to mole presence at any time in the past and perceived mole pest status. In the
questionnaires, respondents were asked first whether moles were present on their land and then
whethertheyconsideredmolestobepests. Thereisatleastsomepossibilitythataskingwhethera
particularspeciesisapestmight“lead”somerespondentstosaythatitiswhenthatspeciesmightnot
haveappearedonanunpromptedlistofpests. However,thisapproachistransparentandavoidsbias
whenmakingcomparisonsacrosscategoriesof,forexample,respondenttype,farmenterprisetypeetc.
Reportedmolepresencedifferedsignificantlyamongrespondenttypeswithmostfarmersand
amenities, but only 13% of householders, reporting that they had ever had moles on their land
(Figure1a). Themajorityofrespondentsreportingmolepresenceconsideredthemtobepestsandthe
likelihoodofthemdoingsodifferedsignificantlyamongrespondenttypes,withamenitymanagers
themostlikelytoconsidermolesontheirlandaspests(Figure1b). Reportedmolepresenceandpest
statuswererelatedtobothfarmenterpriseandamenitytype(Figure1c–f). Livestockfarmsweremost
likelytoreportmolepresencefollowedbymixedandthenarablefarmers,andofthesefarmerswith
moles,livestockfarmerswerealsomostlikelytoconsiderthempests(Figure1c,d). Molepresence
wasreportedbyaminorityofbowlinggreensandsportsfields,butbymostgolfcourses,ornamental
gardens,parks,racecoursesandotheramenities(Figure1e). Ofthosewithmoles,over96%ofgolf
coursesandracecoursesconsideredmolespeststogetherwiththemajorityofotheramenities(bowling
greenswereexcludedbecausesofewreportedmolepresence)(Figure1f).
Therewasnoevidencethatmolepresencevariedregionally(Figure1g),althoughrespondents
fromWales,ScotlandandnorthernEnglandweremorelikelytoconsidermolesontheirlandaspests
(Figure1h). Soiltypewasrelatedtomolepresence,withmolesoccurringmorefrequentlyonloamy
soilsandleastonclay(Figure1i),butwheremoleswerepresenttherewasnoeffectofsoiltypeonpest
status(Figure1j). Soiltypealsovariedwithregion(χ2 =93.5,p<0.001),withchalkyandclaysoils
(24)
moreprevalentincentralandeastern,andsouth-western,Englandandloamy-peaty-sandysoilsmore
commoninScotland,WalesandnorthernEngland(FigureS2),thussuggestingthatregionalvariation
inthepresenceofmolescouldbeatleastpartlyrelatedtosoiltype.
3.2.2. FactorsAffectingRecentMoleActivityandDamage
Weexaminedtheimpactofthesamefactorsonrecentmoleactivityandwhetherrespondents
consideredthisactivitytobedamaging. Where“recentmoleactivity”and“damage”areusedhere
wereferrespectivelytomoleactivityintheprevious12monthsandperceivedmoledamage. Data
on recent activity indicated that respondents from farms (particularly livestock and mixed farms)
andamenities(particularlygolfcourses),andfromWalesandnorthernEngland,reportedagreater
Animals2016,6,39 6of26
incidenceofrecentactivitythandidhouseholdersandrespondentsfromScotland,centralandeastern
England and south-western England (Figure S3). When those respondents reporting recent mole
activitywereaskediftheyconsideredthistoconstitutedamage,amenitymanagers,livestockfarmers
andrespondentsfromWalesandnorthernEngland,weremorelikelythanotherstosaythattheydid.
Animals 2016, 6, 39 5 of 26
MoredetailsareavailableinTextS10.

FiFgiugruer e1. 1M. oleM porleesepnrcees eanncde manodle mpeoslte stpaetusts, srteastpuesc,tirveeslpye, cbtiyv: e(lay,, bb)y r:esp(ao,ndbe)ntr etsyppoen; d(ce,n dt) tyfaprem;
en(ct,erdp)rfiasrem tyepnet; e(rep, rfi)s eamtyepneit;y (tey,pfe), a(gm, ehn) itryegtiyonp;e ,(i,( gj), sho)il rteygpioe.n ;Am(i,enj)itys otiylpteysp aer.e: ABomweln =it ybotwypliensg
graereen:s, BGoowlfl == gboolfw cloinugrsgerse, eOnrsn, =G oorlnfa=megnotlafl gcaorudresness,, POarrkn = =paorkrns,a Rmaecnet =a lragcaercdoeunrsse,s,P Saprokrt=s =p saprokrst,s
fieRladcse a=ndra Ocetcho =u rostehse,rS apmoretnsit=iess.p Roertgsiofinesl dasrea: nNd =O ntohrt=heortnh Eerngalmanedn,i tCieEs .= Rceengtiroanl sanadre e:aNste=rnn Eonrtghlaenrnd,
SWEn =g lsaonudth,-CwEes=tecrnen Etnragllaanndd, Secaostt e=r nScEotnlagnladn adn,dS WWa=less o=u Wtha-lwese.s StetartnistEicnsg slahnodw,nS acroet r=esSucltost loafn d2 taensdts.
Wales=Wales.Statisticsshownareresultsofχ2tests.
3.2.3. Factors Affecting Mole Control
We examined factors affecting whether historic and recent mole control had been conducted.
Where “historic control” and “recent control” are used here we refer, respectively, to control conducted
at any time in the past and control conducted in the previous 12 months.
Historic control was affected by respondent type, farm enterprise, amenity type, region and soil
type (Figure S4a,c,e,g,i). Patterns of control were generally similar to those reported for mole presence
but occurring at a lower level (Figure S4a–j, e.g., while 93% of farmers reported mole presence, 65%
reported control). One key difference, however, was that historic mole control was related to region
Animals2016,6,39 7of26
3.2.3. FactorsAffectingMoleControl
We examined factors affecting whether historic and recent mole control had been conducted.
Where“historiccontrol”and“recentcontrol”areusedherewerefer,respectively,tocontrolconducted
atanytimeinthepastandcontrolconductedintheprevious12months.
Historiccontrolwasaffectedbyrespondenttype,farmenterprise,amenitytype,regionandsoil
type(FigureS4a,c,e,g,i). Patternsofcontrolweregenerallysimilartothosereportedformolepresence
butoccurringatalowerlevel(FigureS4a–j,e.g.,while93%offarmersreportedmolepresence,65%
reportedcontrol). Onekeydifference,however,wasthathistoricmolecontrolwasrelatedtoregion
(whereashistoricpresencewasnot), withcontrolmoreprevalentinWales, Scotlandandnorthern
England(χ2 =33.1,p<0.001,FigureS4g).
(4)
Of those respondents that had ever controlled moles, there was no evidence for difference
amongfarmenterprises,amenitytypesorregions,intheproportionthatcontrolledthemrecently
(FigureS4d,f,h). Thissuggeststhatwhetherahistoriccontrollertendedtocontrolmolesfromyearto
yearwasnotaffectedbythesefactors. Howeverthelikelihoodthatahistoricmolecontrollercontrolled
molesrecentlywasaffectedbyrespondenttypeandsoiltype,withamenitymanagersandfarmers,
and respondents on peaty or sandy soil, being more likely to have controlled moles recently and
perhapsthereforeregularly(FigureS4b,j).
3.2.4. CostsofMoleDamageandControl
Meancostsofdamageandcontrolwerecalculatedforrespondentsreportingdamageorcontrol
respectivelyinthepreviousyear. Totalcontrolcostscomprisedprofessionalcosts(asreported)and
non-professionalcosts(whichwerecalculatedbyaddingthereportedcostofmaterialstotheestimated
cost of labour—produced by multiplying the reported number of hours spent on mole control by
theUKhourlyminimumwagerateforpeopleaged22yearsorabove(£5.73,theequivalentof£7.10
in2014[8])).
There was no evidence that raw damage costs per holding differed among respondent types
(KruskalWallis(KW)χ2 =1.58,p=0.45). Incontrast,rawtotalcontrolcostsdifferedsignificantly
(2)
amongrespondenttypes(Figure2a,KWχ2 =21.70,p<0.001),withthoseforamenitiesbeinggreatest,
(2)
followedbyfarmsandthenhouseholds;underlyingprofessionalandnon-professionalcontrolcosts
followedasimilarpatternbutdidnotdiffersignificantlyamongrespondenttypes(KWχ2 ď5.56,
(2)
pě0.06). Whencostswereexpressedperha,damage,totalcontrolandprofessionalcontrolcostsall
differedsignificantlyamongrespondenttypes,withthoseforhouseholdsbeinggreatest,followedby
amenitiesandthenfarms(Figure2b,KWχ2 ě5.82,pď0.05),butprofessionalcontrolcostsdidnot
(2)
(KWχ2 =4.71,p=0.10).
(2)
Morerespondentsreportedcontrolcoststhanreporteddamagecosts(seesamplesizesinFigure2b
legend: farms150/24,amenities89/19,householders4/2),andamenitiesspentmoreoncontrolthan
theysustainedindamage,whilefarmersandaverysmallsampleofhouseholderssustainedagreater
valueofdamagethantheyspentoncontrol(basedonmedianvalues).
Damage and control costs¨ha´1 for farmers reporting damage or control, respectively, were
greatestforlivestockfarmers,followedbymixedandarablefarmers. Damagecostsandtotalcontrol
costsvariedmarginallysignificantly(KWχ2 =5.54,p=0.063)andsignificantly(KWχ2 =15.07,
(2) (2)
p<0.001),respectively,amongfarmenterprises,butprofessionalandnon-professionalcontrolcosts
didnot(Figure3a,KWχ2 ď2.69,pě0.260).
(2)
Samplesizesweresmallforsomeamenitytypesbutneverthelesstherewasasignificantdifference
amongamenitytypesinbothtotalandprofessionalcontrolcosts¨ha´1 (KWχ2 ě11.5,pď0.02),
(4)
withracecoursessufferingthegreatesttotalcosts¨ha´1(NBtherelativelylargecostsforsportsfields
were reported by very few respondents). There was no significant difference in damage costs or
non-professionalcontrolcosts(Figure3b,KWχ2 ď7.03,pě0.13).
(4)
Animals 2016, 6, 39 7 of 26
Animals2016,6,39 8of26

FFigiguurer e22. .DDamamaaggee aanndd ccoonntrtrool lccoossttss ffoorr ffaarrmmss,, aammeenniittiieess aanndd hhoouusseehhoollddss ((rreessppoonnddeennttssw witithhd daammaaggeeo orr
coconndduuctcitnign gcocnotnrtorlo)l: )(:a()a R)Rawaw cocsotsst spepre hrohlodlidnign g(d(admamagaeg-efa-framrms ns n= 2=62, 6a,maemneitnieitsi ens =n 2=1,2 h1,ohuoseuhsoehldosl dns =
2;n t=ot2a;l tocotanltrcooln-ftarorml-fsa rnm s= n1=571, 5a7m, aemnietineist iens n= =989,8 ,hhoouusseehhooldlds snn == 55;; pprroofefessssioionnaall cocnontrtorol-lf-aframrmss
nn == 226699,, aammeenniittiieessn n= =1 3103,0h,o uhsoeuhsoelhdoslnds= n6; n= o6n;- pnroonfe-spsrioofneaslscioonnatrlo lc-ofanrtmrosl-nfa=rm16s8 ,na m= e1n6i8ti,e sanm=en1i0ti8e,s
nh =o 1u0s8e,h hooldussenho=ld5s); n( b=) 5C);o (sbt)s ¨Choas´ts1·h(da−a1m (daagme-afgarem-fasrnm=s n2 4=, 2a4m, aemnietineistines= n 1=9 1,9h,o huosuesheohldolsdns n= =2 ;2t; ototatall
coconntrtorol-lf-afarmrmss nn == 115500, ,aammeenniittiieess nn == 8899,, hhoouusseehhoollddss nn == 44;; pprrooffeessssiioonnaall ccoonnttrrooll--ffaarrmmssn n= =2 25555,,a ammeennitiiteises
n=119,householdsn=5;non-professionalcontrol-farmsn=161,amenitiesn=99,householdsn=4).
n = 119, households n = 5; non-professional control-farms n = 161, amenities n = 99, households n = 4).
Barsaremeanswithstandarderrors,anddotsindicatemedianvalues.
Bars are means with standard errors, and dots indicate median values.
Animals 2016, 6, 39 8 of 26
Animals2016,6,39 9of26

FFigiguurree 33. .DDamamagaeg eanandd ccoonntrtorol lccoosststs·h¨ah−a1´, 1a,nadn dtottaolt aflinfiannacniacli alloslosessse sdudeu etot ommoloel eacatcitviivtiyt·yh¨ah−1a,´ b1y,:
(ab)y f:ar(ma) efanrtmerpernistee r(pdraimseag(dea-amraabglee- nar =a 5b,l elivnes=to5c,k lniv =e 7st, omcikxend =n =7 ,11m; tioxetadl cnon=tr1o1l-;atroatballe cno =n 2tr8o, ll-iavreasbtoleck
nn == 2783,, livmeisxteodc knn == 7432,; mpirxoefdesnsi=on4a2l; pcoronfterossl-iaornaabllec onnt r=o l-4a8ra, bllievenst=oc4k8 ,nli v=e st1o2c0k, nm=ix1e2d0 ,nm i=x ed78;
nnon=-p7r8o;fensosnio-pnraol fceosnstiroonla-alrcaobnletr no l=- a3r0a, blilveensto=ck3 0n, =l i7v8e,s mtoicxkedn n= = 7485,);m (bi)x aemdenn=ity4 t5y)p;e(b (d)aammaegneit-ygatrydpeens
n( d=a 3m, gagoelf- gcoarudrseenss nn == 73, ,pgaorklfsc no u=r 6se, srance=co7u,rpsaersk ns =n 2=, s6p,orartcse cfioeuldrsse ns =n 1=; t2o,tsapl ocrotnstfiroell-dgsarnd=en1s; nt o=t a2l8,
gcoolnf tcrooul-rgseasr dne =n s27n, p=a2rk8s, gn o=l f14co, ruarcseecsonur=se2s 7n, =p a1r5k, sspnor=ts1 f4ie,lrdasc enc =o u3r; spersofnes=sio15n,als pcoonrttsrofil-egldarsdnen=s n3; =
4p4r, ogfoeslfs icoonuarlsceos nnt r=o l3-g5a, rpdaernkss nn == 4146,,g roalcfeccoouurrsseess nn= =3 159,,p saprkosrtns =fie1l6d,sr anc e=c 3o;u nrsoens-pnr=of1e9s,sisopnoarlt scfioneltdrosl-
gnar=de3n;ns onn =- p2r8o, fgeosslfi ocnoaulrsceosn tnr o=l -2g9a, rpdaernkss nn == 2185,, rgaoclefccoouurrsseess nn == 2209, ,sppaorrktss fnie=ld1s5 n, r=a 5ce).c Bouarrss easren m=e2a0n,s
wspitohr ststafinedldarsdn e=rr5o)r.sB, aanrsda dreotms einadniscwatiet hmsetdaniadna vrdaleurerso.r s,anddotsindicatemedianvalues.
33.2.2.5.5. .SSeeaassoonnaal lPPaattteterrnnss inin MMoolele AAcctitvivitiyty aanndd CCoonnttrrool l
WWee eexxaammiinneedd sseeaassoonnaal lppaattteterrnnss inin rreecceennt tmmoolele aacctitvivitiyty aanndd ccoonntrtorol.l .FFirisrts twwe easakskeded rersepspoonnddenentst sto
rtaonrka tnhke tthhereteh rmeeonmthosn tinh sthine tphreevpiroeuvsi oyuesary iena rwihniwchh micohlem aoclteivaicttyi vwitays wgraesagterseta. tWeset. tWheent halelnocaaltleodca at e“d3”
toa t“h3e” mtoonththe rmanonkethd rhaingkheedst,h “i2g”h etos tt,h“e2 m”otontthh eramnkoendth sercaonnkde dansdec “o1n”d toa nthde “m1”ontotht rhaenmkeodn tthhirrda.n Fkreodm
ththeisred .nFurmombetrhs ewsee npurmodbuecresdw meeparnod ruelcaetdivme eraannkrienlagtsi vfoerr amnokninthglsyf oacrtmivoitnyt;h olyvearcatlilv, iatyct;iovviteyr arlelp,aocrttievdit byy
arlel preosrpteodnbdyenatlsl rveasrpieodn daecnrotsssv tahriee dmaocnrtohsss (tFhreiemdmonatnh’ss (χF2r(i1e1)d =m 1a3n3’1s.0χ,2 p(1 1<) =0.010313)1. .0P,aptt<er0n.s0 0o1n) .fParamttes rannsd
aomnefnairtmiess awnderaem bernoaitdielsy wsiemreilbarro waditlhy sai mlairlagrerw sitphrianlga rpgeearks parnindg ap semakaallnedr oansem ianl lethreo naeuitnumthne,a wutiuthm tnh,e
swpriitnhgt hpeeaskp rbienigngp emakorbee eixnaggmgeorraeteedx afogrg fearramteedrsfo thrafanr ammeersnitthieasn aanmde tnhiet iaeustaunmdnt hpeeaaku tmuomrne ppreoankomunocreed
fporr oanmoeunnictieeds fthorana mfaernmiteiress (tFhiganurfea r4ma)e. rTsh(eF ivgeuryre s4maa).ll Tnhuemvbeerry osfm hoalulsneuhomldbeerrso tfhhato uressephoonlddeerds ttoh athte
qrueespstoionnd erdeptoortthede qau seinstgiolen preeapko rinte dacativsiintyg lien ptheaek suinmamcteivr.i t yinthesummer.
Animals 2016, 6, 39 9 of 26
We asked respondents to report the months in which they conducted mole control during the
previous year and plotted the proportion of responses for each month (Figure 4b). Control patterns
broadly followed activity patterns. Overall, control reported by all respondents varied over the year
(χ2(11) = 259.7, p < 0.001). Patterns in control differed between farmers and amenities (χ2(11) = 67.0,
p < 0.001), but data for householders were too few for testing and care should be taken in interpreting
householder figures as a result. Seasonal patterns in mole control did not differ among farm enterprise
tyApniemsa l(sχ220(3136) ,=6 ,2379.3, p = 0.745). Data for some categories of amenity were too few for testing. 10of26

FFigiguurere 44. .SSeeaassoonnaal lppaattteterrnnss iinn mmoollee aaccttiivviittyy aanndd ccoonnttrrooll iinn tthhee pprreevviioouuss yyeeaarr,,b byyr reessppoonnddeennttt ytyppe,eb, absaesded
oonn: :(a(a) )mmeeaann rraannkkeedd mmoonntthhllyy aaccttiivviittyy ((ffaarrmmss nn == 449966;; aammeenniittiieess nn= = 116688;;h hoouusseehhooldldssn n= =1 111),)s, tsatnadndaradrd
eerrrororsrs aarree sshhoowwnn; ;((bb)) pprrooppoorrttiioonn ooff rreessppoonnddeennttss ccoonndduuccttiinngg ccoonnttrrooll eeaacchh mmoonntthh iinn tthheep prreevvioiouussy yeeaar,r,
bbyy reressppoonnddeennt ttytyppee (f(afarrmmss nn == 227722; ;aammeennitiiteies snn == 13123;2 h;hoouuseshehooldlds snn == 6)6. ).
3.2.6. Mole Habitats
Weaskedrespondentstoreportthemonthsinwhichtheyconductedmolecontrolduringthe
prevTiohuersey weaars annod epvliodtetendcet hfoerp ar orpeloarttiioonnshoifpr ebseptwoneseens tfhoer ehaacbhitmatso nptrhes(eFnigt uorne r4ebs)p.oCnodnetnrotsl’ plaanttde rannsd
ebitrhoeard mlyofloel lpoewset dstaactutisv iotyr rpeactetenrtn ms.oOlev aecratilvl,itcyo,n ftorro lfarermposr t(eχd2(8b) y≤ a1l2l.r2e, spp o≥n 0d.1e4n4ts), vaamrieenditoievse r(χth2(e4) y≤e 2a.r2,
p( χ≥2 (01.16)9=5)2 o5r9 .h7,opus<eh0o.0ld01s )(.χP2(a5)t t≤e r2n.6s, inp ≥co 0n.4tr5o9l).d Hiffoewreedvebre,t whaebeintaftas rwmietrhs raenpdoratmede nreitcieenst( χm2o(1l1e) =ac6ti7v.i0t,y
p<0.001),butdataforhouseholdersweretoofewfortestingandcareshouldbetakenininterpreting
householderfiguresasaresult. Seasonalpatternsinmolecontroldidnotdifferamongfarmenterprise
types(χ2 =27.3,p=0.745). Dataforsomecategoriesofamenityweretoofewfortesting.
(33)
3.2.6. MoleHabitats
There was no evidence for a relationship between the habitats present on respondents’ land
and either mole pest status or recent mole activity, for farms (χ2 ď 12.2, p ě 0.144), amenities
(8)