AbstractIn the Weidlingbach, a low‐order forest stream in the Wienerwald area near Vienna (Austria), hydraulic stress was measured at 112 locations from which benthic fauna (=33318 specimens of macro‐invertebrates) was collected between March and September 1995. For measuring hydraulic stress a set of FST hemispheres was used. The most abundant taxa studied (= 90.7% of the total) wereGammarus fossarumKoch (Amphipoda),Leuctraspp. (Plecoptera), the ephemeropteransBaetis rhodani(Pictet),B. vernus(Curtis),Habroleptoides confusaSartori and Jacob,Ecdyonurus starmachiSowa and the caddisflyHydropsyche instabilis(Curtis).Five mayfly, four stonefly and six caddisfly taxa significantly (p<0.05) preferred the lotic subsection of the research area, whereasEphemera danicaMüller significantly (p0.05) over the whole range of hydraulic stress, independent of disch