Fear begets function in the 'brown' world of detrital food webs

Theory suggests that predators in detritus-based food webs should negatively influence plants, through direct effects on plant-facilitating detritivores. In a three-level food web of predaceous beetles, earthworms and plants, Zhao et al. (2013) report evidence to the contrary. They found that predators drove positive indirect effects on both plant-facilitating soil properties and above-ground plant biomass and that these positive effects were driven by predator-mediated vertical shifts in detritivore habitat use. Their study reinforces the importance of trait-mediated indirect interactions across both 'green' and 'brown' trophic cascades and emphasizes that understanding the spatial dimension of trophic cascade mechanisms remains a critical research priority.