Background:Attentionhasrecentlybeendrawntotheissueoftransboundaryinvasions,wherespeciesintroducedandnaturalizedinonecountrycrossinternationalbordersandbecomeproblematicinneighbouringcountries.Robustmodellingframeworks,abletoidentifytheenvironmentaldriversofinvasionandforecastthecurrentandfuturepotentialdistributionofinvasivespecies,areneededtostudyandmanageinvasions.Limitationsduetothelackofspeciesdistributionandenvironmentaldata,orassumptionsofmodellingtools,oftenconstrainthereliabilityofmodelpredictions.Methods:Wepresentamultiscalespatialmodellingframeworkfortransboundaryinvasions,incorporatingrobustmodellingframeworks(MultimodelInferenceandEnsembleModelling)toovercomesomeofthelimitations.TheframeworkisillustratedusingHakeasericeaSchrad.(Proteaceae),ashruborsmalltreenativetoAustraliaandinvasiveinseveralregionsoftheworld,includingtheIberianPeninsula.Twostudyscaleswereconsidered:regionalscale(westernIberia,includingmainlandPortugalandGalicia)andlocalscale(northwestPortugal).Attheregionalscale,therelativeimportanceofenvironmentalpredictorssetswasevaluatedandrankedtodeterminethemaingeneraldriversforthespeciesdistribution,whiletheimportanceofeachenvironmentalpredictorwasassessedatthelocalscale.ThepotentialdistributionofH.sericeawasspatiallyprojectedforbothscaleareas.Results:ModelprojectionsforwesternIberiasuggestthatalargeareaisenvironmentallysuitableinbothPortugalandSpain.Climateandlandscapecompositionsetswerethemostimportantdeterminantsofthisregionaldistributionofthespecies.Conversely,ageologicalpredictor(schistlithology)wasmoreimportantinexplainingitslocal-scaledistribution.Conclusions:AfterbeingintroducedtoPortugal,H.sericeahasbecomeatransboundaryinvaderbyexpandinginpartsofGalicia(Spain).ThefactthatalargerareaispredictedasenvironmentallysuitableinSpainraisesconcern
