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10:20
Linking Predation Risk, Herbivore Physiological Stress and Microbial Decomposition of Plant Litter
Published on: March 12, 2013
Predation risk, stoichiometric plasticity and ecosystem elemental cycling
Shawn J Leroux1, Dror Hawlena, Oswald J Schmitz
1Department of Biology, University of Ottawa, Ottawa, Ontario, Canada , K1N 6N5.
Proceedings. Biological Sciences
|August 17, 2012
Summary
Predation risk alters herbivore needs from nitrogen to carbohydrates, impacting ecosystem nutrient cycling. This highlights the importance of considering physiological changes in ecological models.
Area of Science:
- Ecology
- Ecosystem Dynamics
- Nutrient Cycling
Background:
- Traditionally, herbivore production is nitrogen-limited, influencing ecosystem elemental cycling.
- Emerging evidence suggests predation risk alters herbivore metabolism, shifting demand from nitrogen to carbohydrates.
Purpose of the Study:
- To investigate how predation risk affects herbivore elemental demands and ecosystem cycling.
- To evaluate the role of soluble plant carbon in ecosystem stoichiometry under varying predation risk.
Main Methods:
- Developed a stoichiometrically explicit ecosystem model tracking nitrogen, soluble carbon, and recalcitrant carbon.
- Simulated ecosystem responses with and without predation risk to assess the influence of soluble plant carbon.
Main Results:
- Without predation risk, herbivores are nitrogen-limited, with minimal impact from soluble plant carbon.
- With predation risk, herbivores become soluble carbon-limited, releasing excess nitrogen and significantly impacting ecosystem carbon and nitrogen dynamics.
- Plant soluble carbon critically influences ecosystem stocks and flows when herbivores face predation risk.
Conclusions:
- Predation risk fundamentally alters herbivore limitations, shifting them from nitrogen to soluble carbon.
- Ecosystem elemental cycling and stoichiometric balance are sensitive to herbivore physiological plasticity in response to predation.
- Standard C:N ratios may be insufficient for describing ecosystem limitations when soluble and recalcitrant carbon pools are not differentiated.
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