Physiological stress as a fundamental mechanism linking predation to ecosystem functioning.

Area of Science:

• Ecology
• Environmental Science
• Zoology

Background:

• Ecosystem properties exhibit context dependency, influenced by various ecological factors.
• Prey responses to predation risk are critical but often overlooked drivers of ecosystem dynamics.
• Understanding physiological stress mechanisms in prey is key to deciphering ecosystem functions.

Purpose of the Study:

• To present a framework explaining how prey stress responses to predation resolve context dependency in ecosystem properties.
• To synthesize evidence for prey physiological responses to predation risk across taxa.
• To illustrate the ecological consequences of prey stress on ecosystem dynamics, including food chain length and nutrient cycling.

Main Methods:

• Described major nonspecific physiological stress mechanisms and their ecological consequences.
• Synthesized evidence for prey physiological responses to predation risk.
• Applied understanding of stress consequences to explain herbivore-prey interactions and ecosystem dynamics.

Main Results:

• Prey physiological responses to predation risk are consistent across taxa and align with general stress paradigms.
• Stressed herbivores preferentially consume carbohydrate-rich plants, altering plant community composition and detrital input.
• Prey stress impacts the elemental composition and energy content of waste products and carcasses entering the detrital pool.

Conclusions:

• Prey stress responses to predation can resolve context dependency in ecosystem functions like food chain length and nutrient cycling.
• Lowered energy and nutrient conversion efficiency due to prey stress weakens the link between ecosystem productivity and food chain length.
• The proposed framework provides a unified understanding of how physiological stress in prey shapes ecosystem properties and functions.