That is, Hypothesis II-1 predicts that higher prey diversity increases predator consumption and trophic transfer between predators and prey via wider diet breadth or more diverse and balanced resources for predators (the balance diet hypothesis ). There are also two contrasting hypotheses about how prey diversity affects predators through bottom-up controls. This prediction considers interference, such as intraguild predation among predators, as a potential consequence of elevated predator diversity. In contrast, Hypothesis I-2 predicts that predator diversity decreases consumption and trophic transfer. The assumption underlying this hypothesis is that higher predator diversity strengthens the top-down control on prey through diet niche partitioning and thus increases the total consumption by predators. These hypotheses predict opposing effects of diversity on trophic transfer as follows: from the aspect of predator diversity, Hypothesis I-1 predicts that higher predator diversity enhances the total amount of consumption and thus promotes trophic transfer. Multiple hypotheses have been established in terms of trophic interactions mediated by diversity effects of predators and prey, respectively (Fig. Examples of these differences include: the degree of intraguild predation in the food web the proportion of generalists present at the predator level and the amount of edible species at the prey level. Disagreements over these biodiversity effects between previous studies are partly attributed to the differences in trophic structure of the studied predator–prey interactions. However, a point of concern is that multi-trophic biodiversity effects are complex (e.g., the direction and strength of effect) and the issue remains controversial (e.g., ). Over the last decade, increasing evidence of significant biodiversity effects on ecosystem functioning through trophic interactions (e.g., predator–prey interactions and flux of energy and matter) has highlighted the need to go beyond single-trophic-level diversity effects (e.g., ). The majority of studies on this topic, however, have focused on single-trophic levels.

Our findings highlight the importance of considering multi-trophic biodiversity effects on ecosystem functioning in natural ecosystems.Īnthropogenic disturbance on natural environments demands a greater understanding of the consequences of biodiversity change on ecosystem functioning.

Notably, we found prey diversity effects on predator–prey interactions whereas, we found no significant diversity effect on biomass within the same trophic level. By contrast, no clear effect was detected for predator diversity on prey biomass and transfer efficiency. We found higher prey diversity enhanced both diversity and biomass of predators, as well as trophic transfer efficiency, which may arise from more balanced diet and/or enhanced niche complementarity owing to higher prey diversity. Specifically, we investigated: (i) predator diversity effects on prey biomass and trophic transfer efficiency (using the biomass ratio of predator/prey as a proxy), (ii) prey diversity effects on predator biomass and trophic transfer efficiency, and (iii) the relationship between predator and prey diversity. Here we examined diversity and biomass of bacteria (prey) and nanoflagellates (predators), as well as their effects on trophic transfer efficiency in the East China Sea. However, this topic has rarely been explored for marine microbes, even though microbial biodiversity contributes significantly to marine ecosystem function and energy flows. The importance of biodiversity effects on ecosystem functioning across trophic levels, especially via predatory–prey interactions, is receiving increased recognition.

Cute predators vs prey