A dominant plant species and insects interactively shape plant community structure and an ecosystem function

Dominant plants and insects both structure plant communities and determine key ecosystem functions. However, dominant plants and insects can have opposing effects on plant community structure and ecosystem function. Critically, few studies have assessed the combined effects of these two drivers of plant community structure and ecosystem function. In this study, we factorially manipulated the presence of the dominant plant species Solidago canadensis (Canada goldenrod) and insects in an old field to quantify their independent and interactive effects on the plant community. Insect presence mediated the effects of S. canadensis removal on plant biomass and richness. Total plant biomass was ~32% lower following S. canadensis removal only when insects were present. In contrast, subdominant plant biomass was ~75% higher following S. canadensis removal, but only when insects were reduced. Subdominant species richness was ~37% higher following S. canadensis removal when insects were present, t..., , , # A dominant plant species and insects interactively shape plant community structure and an ecosystem function

[https://doi.org/10.5061/dryad.2ngf1vj0d](https://doi.org/10.5061/dryad.2ngf1vj0d)

## Description of the data and file structure

We conducted a full factorial experiment where we manipulated the presence of the dominant plant species *Solidago canadensis* (Canada goldenrod) and insect herbivores in an old-field ecosystem in Michigan. We established 24 5 × 5 meter plots that were at least one meter apart. Within each 5 × 5 meter plot, we manipulated *S. canadensis* presence in two 1 × 1 meter subplots at two levels: (1) *S. canadensis* removal and (2) undisturbed control. In *S. canadensis* removal subplots, we removed *S. canadensis* stems by clipping all stems at the soil level. In undisturbed control subplots, we did not remove any plant biomass. We additionally established one 1 × 1-meter random biomass removal subplot within each 5 × 5-meter plot, wherein we removed the ...