Consumers stabilize grassland ecosystem functions by destabilizing belowground communities under abiotic stress

Area of Science:

• Ecology
• Soil Science
• Microbial Ecology

Background:

• Consumers are crucial for ecosystem responses to environmental stress, but their role in belowground processes is understudied.
• Insect consumers significantly influence grassland ecosystem function and stability, particularly in response to abiotic stressors like drought.

Purpose of the Study:

• To investigate how small-bodied consumers affect the stability of grassland belowground functions under varying abiotic stress.
• To understand the mechanisms by which consumers influence microbial communities and ecosystem stability.

Main Methods:

• A fully factorial field experiment manipulated consumer presence and induced drought over a growing season.
• Measurements included bacterial biomass, microbial activity, and soil bacterial and fungal community composition and abundance.

Main Results:

• Consumer presence stabilized bacterial biomass and microbial activity across fluctuating soil moisture conditions.
• Ecosystem stability was enhanced by a consumer-driven destabilization of microbial communities, evidenced by increased variability in composition and abundance.
• Consumers altered soil bacterial communities (composition, richness) but had minimal impact on fungal communities.

Conclusions:

• Consumers play a vital role in maintaining belowground ecosystem stability in grasslands, especially under drought.
• Community responsiveness and rapid adaptability are key dimensions of ecosystem stability.
• Trophic interactions must be considered when predicting grassland ecosystem responses to global change.