Ecologists have recently been cautioned about the potential for complex interactive artefacts to complicate the interpretation of field and laborator experiments. This study in northern Australia tested for such effects in 2 methods commonly used to investigate herbivory and predation in mangrove forests: tethering and caging. There was no evidence that teethering leaves or propagules caused biases which would invalidate comparisons among habitats, but the method was likely to underestimate the intensity of feeding on propagules. There was also little evidence that cages had any effect on seedlings other than to reduce the intensity of herbivory. The results indicate that these methods are likely to provide useful, and non-problematic, information about the role of herbivory in mangrove forests.