A Dominant Plant Species and Insects Independently and Interactively Shape Plant Community Structure and Ecosystem...

Area of Science:

• Ecology
• Plant-insect interactions
• Community ecology

Background:

• Dominant plant species and insect herbivores are key drivers of terrestrial ecosystem structure and function.
• Few studies have investigated the combined, long-term, above- and below-ground effects of these drivers.

Purpose of the Study:

• To investigate the interactive effects of the dominant plant Solidago canadensis (Canada goldenrod) and insect herbivores on plant community structure and ecosystem function over three years.
• To quantify impacts on plant diversity, biomass, functional traits, microclimate, and decomposition.

Main Methods:

• Factorial manipulation of Solidago canadensis presence/absence and insect herbivore levels in an old-field ecosystem over three years.
• Quantification of plant community metrics, functional traits, microclimate variables, and soil organic matter decomposition rates.

Main Results:

• Solidago canadensis and insect herbivores independently and interactively influenced plant biomass, richness, functional traits, microclimate, and decomposition.
• Removal of S. canadensis and reduction of insects increased plant community biomass and decomposition rates, linked to improved light and soil moisture.
• Plant functional traits, like height, shifted with S. canadensis removal and insect reduction.
• Temporal stability of aboveground biomass decreased with S. canadensis removal and insect reduction, but species richness was unaffected.
• Insect herbivores inhibited biomass recovery following S. canadensis removal.

Conclusions:

• The combined effects of dominant plants and insect herbivores are crucial for understanding community and ecosystem dynamics, both above and below ground.
• Insect herbivores play a significant role in mediating ecosystem recovery processes after disturbances like dominant plant removal.