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Correctly assessing whether rangeland ecosystem services are stable, improving, or degrading is of local to global importance.� In the USA, several plant and soil properties are measured as part of a standardized system for assessing rangeland health.� Here a series of field experiments were used to test the reliability of a primary putative indicator (i.e. soil aggregate stability) of rangeland management and ecosystem function in the Northern Great Plains.� First, we tested whether livestock grazing pressure consistently reduced soil aggregate stability.� Second, we tested whether appreciable variation in soil water transport (infiltration) was explained by aggregate stability.� Data from a multi-factor field experiment was used to determine the best predictor(s) of infiltration and contributed to a meta-analysis that tested the generality of the expected positive aggregate-infiltration association.� In one of two field experiments, livestock grazing pressure tended to reduce the stability of small (easily erodible fraction) macroaggregates (0.25-1 mm).� In the other experiment and for larger macroaggregates (1-2 mm), grazing had no appreciable impact on aggregate stability.� The multi-factor field experiment affected several plant and soil properties.� Multiple regression analyses of these data determined that variation in infiltration was best explained by plant community composition variables but not soil properties.� With a meta-analysis of these and other data from the Northern Great Plains, we found no general aggregate-infiltration association.� Our findings counter prevailing scientific and management expectations on the functioning of key soil health indicators but support plant species-infiltration linkages consistent with bioturbation theory.� Designing rangeland health monitoring systems with empirically validated predictors of ecosystem function is a logical next step towards better health assessment.