Abstract Detail

The Odum Legacy: Plant Systems Across Scales

Tuominen, L.K. [1].

Next-Generation Biosafety: Applying Holistic Ecology for Transgenic Risk Assessment.

As a form of synthesis, holistic ecology involves the construction of conceptual models of ecological processes, parameterization of such models with field data, and simulation using these quantitative models. Together with the application of ecological theory, this modeling process has provided quantitative and mathematical validation of the notion that all components of ecological systems are mutually interdependent. In particular, the mathematical basis for the predominance of indirect effects within such systems has been established for over three decades. Holistic ecology is therefore both a counterpoint to and dependent upon reductionist methods that focus on quantifying direct interactions between or among ecosystem components. Compared to evaluations of potential health effects, likelihood of transgenic escape, and competitiveness with other genotypes, the systematic evaluation of transgenic plant genotypes for potential effects on the ecosystems in which they will grow has received little attention. Concerned individuals have long cited this lack of knowledge as one reason for their discomfort with consumer products containing transgenic materials. More recently, field studies have documented perturbation of non-target populations indirectly affected by transgenic plants in agricultural contexts, indicating a need for further investigation. In working towards development of risk assessment simulation methods addressing the potential ecological effects of novel tree genotypes, I have constructed two deterministic ecosystem models focusing on carbon cycling. The first model constitutes an unmanaged forest scenario in which a novel Populus genotype has become established (i.e., transgenic escape scenario). The second model constitutes a forest/plantation interface, where the novel genotype is absent from the unmanaged forest and the plantation is managed to grow only the novel genotype. Proof-of-concept simulations compared control conditions (i.e., wild type and transgenic Populus had identical parameterization) against experimental conditions consistent with an engineering goal of increased biomass production (i.e., transgenic Populus was assigned increased growth, herbivory, and litter decomposition rates). Relative to control conditions, the presence of novel genotypes led to carbon stock perturbations for both abiotic and biotic ecosystem components, establishing proof of concept for a holistic modeling approach towards transgenic risk assessment for ecosystems. In addition, outcomes suggested potential hypotheses for field testing and potential management interventions to reduce perturbations of carbon stocks. Further development will require assessing simulation generality, adding biological variation to parameter values, and incorporating stochasticity in environmental conditions. The models could then be applied to a specific field site via targeted field data collection.

1 - Metropolitan State University, Natural Sciences Department, 700 East Seventh Street, St. Paul, MN, 55106, USA

Keywords:
transgenic risk assessment
ecosystem simulation
novel genotypes
Populus spp.
metabolic engineering.

Presentation Type: Symposium Presentation
Session: SY02, The Odum Legacy: Plant Systems Across Scales
Location: Chatham Ballroom - C/Savannah International Trade and Convention Center
Date: Monday, August 1st, 2016
Time: 10:30 AM
Number: SY02005
Abstract ID:101
Candidate for Awards:None