accepted

Tree species richness strengthens relationships between ants and the functional composition of spider assemblages in a highly diverse forest

2014-06-18

2015-01-28

Biotropica

2014-07-01

In species-rich ecosystems such as (sub)tropical forests, higher trophic level interactions often play key functional roles. Plant species loss may alter these interactions, but particularly among predators intraguild interactions might modify net interaction effects in the interplay with plant diversity. Empirical evidence is scarce, however, and we lack a clear understanding of these processes in species-rich systems. Here, we analyze the relationship between spiders and ants—two of the dominant arthropod taxa in many ecosystems—across a gradient from medium to high woody plant species richness in a highly diverse subtropical forest in south-east China. Specifically, we test for the effects of ants and tree species richness on the biomass and functional composition of spider assemblages, aiming to provide insight into the potential mechanisms underlying the previously observed lack of an overall effect of predator top-down control in this system. We hypothesize that (i) ant presence and biomass decrease the biomass and shift the functional composition of spider assemblages at the plant community level, and that (ii) the effects of ants on spiders will be mediated by woody plant species richness.

Andreas Schuldt, Michael Staab, Helge Bruelheide, Prof., Karin Nadrowski, Martin Böhnke