Ecosystem engineering strengthens bottom-up and weakens top-down effects via trait-mediated indirect interactions

Area of Science:

• Ecology
• Ecosystem Dynamics
• Behavioral Ecology

Background:

• Trophic interactions and ecosystem engineering are key drivers of ecosystem structure.
• The interplay between these forces and the mechanisms (density- vs. trait-mediated) driving trophic effects remain unclear at natural scales.
• Previous microcosm studies suggest trait-mediated interactions can be as significant as density-mediated ones.

Purpose of the Study:

• To investigate how ecosystem engineering influences trophic interactions.
• To explore the role of ecological scale in mediating density- and trait-mediated pathways.
• To understand the combined effects of engineering and trophic interactions on ecosystem structure.

Main Methods:

• Integration of large-scale field experiments with microcosm studies.
• Examination of ecosystem engineering effects on trophic interactions across different scales.
• Analysis of density-mediated versus trait-mediated interaction pathways.

Main Results:

• Ecosystem engineering significantly alters the balance between top-down and bottom-up trophic interactions.
• Cryptic trait-mediated interactions were identified as a key driver of these engineering effects.
• The relative importance of density- and trait-mediated pathways is dependent on the ecological scale.

Conclusions:

• Ecosystem engineering, trophic interactions, and ecological scale interact dynamically to structure ecosystems.
• Trait-mediated effects are crucial, often hidden, components of ecosystem engineering impacts.
• Scale-dependent pathways highlight the complexity of predicting ecosystem responses to engineering.