Figure 1.

A trophic pyramid for our study system. Within trophic layers, negative density-dependence has been studied in the context of population regulation. For instance, as population size increases an individual's state (e.g. body mass) decreases, which negatively affects their reproductive output and survival probability. Here, we focus on the effect that negative density-dependence among prey has on their predators. Negative density-dependence occurs within all trophic levels. Likewise, the effects of density-dependence occur between all trophic levels. Dashed lines represent negative interaction pathways, and solid lines represent positive interaction pathways. The red arrow represents the focus of this study, i.e. the between trophic-level effect of density-dependence on body mass. Photo courtesy: Jan van de Kam (Falco peregrinus and Calidris canutus), Allert Bijleveld (Cerastoderma edule) and NIOZ (collection of phytoplankton species).