Identifying hazards in complex ecological systems. Part 3: Hierarchical Holographic Model for herbicide tolerant oilseed rape

Abstract

This paper is the third in a series designed to demonstrate the application of rigorous, systematic hazard identification techniques to ecological systems. Here we use Hierarchical Holographic Modelling to identify the potential ecological hazards associated with the commercial release of herbicide tolerant oilseed rape. Hierarchical Holographic Models decompose complex systems into a series of sub-systems and consider interactions between the components and processes of these sub-systems in order to identify hazards. In this example we considered 1356 potential interactions between the biological, chemical and physical components and processes of the herbicide tolerant oilseed rape environment, and identified 152 potential hazards, grouped into 14 categories. The hazards were subsequently scored for degree of concern and plausibility, and then compared with an equivalent list of hazards generated independently by a checklist approach. The incidence of herbicide tolerant volunteers (and weeds) both on and off the farm had the highest average score of all the ecological hazard categories. The checklist based approach identified or implied 44% of the hazards identified in the Hierarchical Holographic Model, including nine of the ten hazards ranked most important. The checklist approach focussed almost exclusively on the phenotypic and genotypic hazards associated with herbicide tolerant oilseed rape and largely ignored the hazards associated with the circumstances surrounding its use. As a result the checklist identified only 6 out of the 79 potential hazards associated with changes to farming practice. The commercial release of herbicide tolerant oilseed rape will be associated with changes in tillage and the application of post-emergent herbicides. It may also lead to changes in spray schedules of insecticide and fungicide. Many of the environmental hazards identified with these changes are plausible and may warrant further investigation or targeted monitoring.

Biological Invasions: Recommendations for U.S. Policy and Management

“…If policy attention and management resources are to be prioritized and cost-effectively applied across pathways, the relative risk posed to the environment, human health, and the economy by different pathways must also be better quantified. This is increasingly possible using new tools for detection of organisms (e.g., genetic tools; see also Recommendation 3) and quantitative analysis of pathways (e.g, network analyses; Hayes et al 2004, Burgman 2005.…”

Identifying indicator species for post-release monitoring of genetically modified, herbicide resistant crops

“…aviation or large scale industrial production facilities. For environmental purposes and ecological systems, before us, also Hayes (1998) used these tools for marine ecosystems but also to identify hazards of GM HR oilseed rape in Australia (Hayes et al 2004). Both were also proposed as valuable tools for risk assessment of GM crops by the US National Research Council (National Research Council 2002).…”

“…'top-event') and then by combining logical functions such as 'and' and 'or', identiWes all events that can or must contribute to the speciWed failure (Hayes et al 2004). An Event Tree is the complementary 'bottom-up' approach where an analyst speciWes an 'initiating event' and lays out the logical chain of events that can occur and lead to a number of possible consequences.…”

Assessing unintended effects of GM plants on biological species

“…All possible direct and indirect risk hypotheses should be constructed; qualitative event-tree and fault-tree analysis can be helpful in this process (Hayes 2002;Hayes et al 2004).…”