Dates: August 2014 – July 2015
Project Title: Stoichiometric food web models: How food quality affects population structures
Angela Peace (Ph.D. Applied Mathematics, Arizona State Univ., 2014) developed ecological stoichiometric population models of two and three trophic levels that investigate the effects of light and nutrient availability on ecological transfer efficiencies (Peace, 2015 Ecological Modeling). The models are two and three dimensional systems of ordinary differential equations, Lotka-Volterra type models, that incorporate two currencies, carbon (C) and phosphorus (P), across trophic levels: phytoplankton, zooplankton, and fish. The models use ecological trophic transfer efficiencies as important gauges of ecosystem function in order to determine the effects of nutrient enrichment, light availability, and food chain length.
An additional complementary research project involved a collaboration to use a quantitative genetic approach to explore the connections between rapid evolution and ecological stoichiometry at both the population and ecosystem level (Masato et al., 2015 Oikos). This involved the incorporation of evolution into ecological stoichiometric models to investigate the effects of rapid evolution of a consumer’s stoichiometric trait (Daphnia P:C ratio) on population dynamics. Model results indicate rapid evolution of the consumer stoichiometric trait (P:C ratio) can cause complex dynamics. For example, rapid evolution can destabilizes population dynamics. In other scenarios rapid evolution can rescue the consumer population from extinction (evolutionary rescue). The model results also show that rapid evolution may influence the level of nutrients available in the environment and the flux of nutrients across trophic levels. The study represents an important step for theoretical integration of rapid evolution and ecological stoichiometry.
After completing her NIMBioS fellowship, Peace accepted a faculty position as an assistant professor in the department of mathematics and statistics at Texas Tech University. Peace will continue to develop and analyze mathematical models of essential elements and their interactions under the framework of ecological stoichiometry. Peace further plans to apply this theory to ecotoxicology modeling by developing models that investigate how co-occurring nutrient and contaminant stressors interact in aquatic systems. These modeling efforts will improve understanding of the processes governing the trophic transfer of nutrients, energy, and toxins and offer insight on the importance of elemental food quality in ecotoxicological testing protocols for assessing risk of exposures to toxins.
LiveScience Profile Q&A with Dr. Peace: Urgently examining environmental impacts of fertilizer run-off
NIMBioS video interview:
The math of chemical elements
Publications while at NIMBioS
Presentations while at NIMBioS
Participation in NIMBioS Activities:
Education, Outreach and Training