Abstract
Biomass is a common, universal indicator of ecosystem productivity for
exploring biodiversity–ecosystem functioning (BEF) relationships in all
types of ecosystems. However, positive BEF is often missing in aquatic
consumer communities with multitrophic interactions. Here, we apply a
new indicator, integrated trophic position (i TP), which is
defined as the summed TPs of all consumers weighed by the relative
biomass of each taxon, for multitrophic systems to test the vertical
diversity hypothesis (VDH) that functional diversity can enhance trophic
energy flows within a food web. Using a meta-community of coastal
benthic macroinvertebrates, we demonstrate that i TP increases in
more diverse communities, supporting the VDH. Comparing our results with
previous findings that stream benthic macroinvertebrates exhibit a
negative BEF in contrast to the VDH, we discuss a possible mechanism to
explain this contrasting pattern. Finally, we use a size-based food web
approach to deepen our mechanistic understanding of the observed BEF.