The　invasion　ecology　principles　illustrated　in　many　ecosystems　have　not　yet　been　explored　in　the　context　of　fomite　transmission.　We　hypothesized　that　invaders　in　fomite　transmission　are　trackable,　are　neutrally　distributed　between　hands　and　environmental　surfaces,　and　exhibit　a　proximity　effect.　To　test　this　hypothesis,　a　surrogate　invader,　Lactobacillus　delbrueckii　subsp.　bulgaricus,　was　spread　by　a　root　carrier　in　an　office　housing　more　than　20　participants　undertaking　normal　activities,　and　the　microbiotas　on　skin　and　environmental　surfaces　were　analyzed　before　and　after　invasion.　First,　we　found　that　the　invader　was　trackable.　Its　identity　and　emission　source　could　be　determined　using　microbial-interaction　networks,　and　the　root　carrier　could　be　identified　using　a　rank　analysis.　Without　prior　information,　L.　bulgaricus　could　be　identified　as　the　invader　emitted　from　a　source　that　exclusively　contained　the　invader,　and　the　probable　root　carrier　could　be　located.　In　addition　to　the　single-taxon　invasion　by　L.　bulgaricus,　multiple-taxon　invasion　was　observed,　as　genera　from　sputum/saliva　exhibited　co-occurrence　relationships　on　skin　and　environmental　surfaces.　Second,　the　invader　had　a　below-neutral　distribution　in　a　neutral　community　model,　suggesting　that　hands　accrued　heavier　invader　contamination　than　environmental　surfaces.　Third,　a　proximity　effect　was　observed　on　a　surface　touch　network.　Invader　contamination　on　surfaces　decreased　with　increasing　geodesic　distance　from　the　hands　of　the　carrier,　indicating　that　the　carrier＇s　touching　behaviors　were　the　main　driver　of　fomite　transmission.　Taken　together,　these　results　demonstrate　the　invasion　ecology　principles　in　fomite　transmission　and　provide　a　general　basis　for　the　management　of　ecological　fomite　transmission.　IMPORTANCE　Fomite　transmission　contributes　to　the　spread　of　many　infectious　diseases.　However,　pathogens　in　fomite　transmission　typically　are　either　investigated　individually　without　considering　the　context　of　native　microbiotas　or　investigated　in　a　nondiscriminatory　way　from　the　dispersal　of　microbiotas.　In　this　study,　we　adopted　an　invasion　ecology　framework　in　which　we　considered　pathogens　as　invaders,　the　surface　environment　as　an　ecosystem,　and　human　behaviors　as　the　driver　of　microbial　dispersal.　With　this　approach,　we　assessed　the　ability　of　quantitative　ecological　theories　to　track　and　forecast　pathogen　movements　in　fomite　transmission.　By　uncovering　the　relationships　between　the　invader　and　native　microbiotas　and　between　human　behaviors　and　invader/microbiota　dispersal,　we　demonstrated　that　fomite　transmission　follows　idiosyncratic　invasion　ecology　principles.　Our　findings　suggest　that　attempts　to　manage　fomite　transmission　for　public　health　purposes　should　focus　on　the　microbial　communities　and　anthropogenic　factors　involved,　in　addition　to　the　pathogens.