Grant: Discovery Grants Program - Individual

In most forest systems, native forest insects and pathogens influence forest structure at small and intermediate scales. The concept that native biotic disturbance agents are natural components of forest ecosystems, and due to co-evolution are in quasi-equilibrium with their hosts, provides a conceptual framework for my proposed research. Changes in climate or host factors, such as availability and vigour, can cause disequilibrium, resulting in greater damage by biotic disturbance agents. This proposal examines linkages among biotic disturbance agents and abiotic environments, and potential effects of climate change and forest management practices on tree and ecosystem health. Recent examples of historically innocuous fungi and insects becoming serious pests or exceeding historic outbreak levels are indicative of emerging diseases or insect pests, and the main drivers behind this are climate and cultural practices. The objectives of this research are to identify mechanisms of disease and insect population limitation in natural systems, with a focus on emerging pests, or those most likely to become emerging pathogens or insect pests. The intent is to enable development of risk models and mitigation strategies that account for the potential influence of biotic disturbance agents on forest health. Four projects are proposed that study the following: 1) the emergence of foliar pathogens as a result of wetter summers; 2) the evolution of foliar defense chemicals in hosts under historic disease pressure; 3) the increase in susceptibility of hosts to one agent due to the activities of a different climate-sensitive disturbance agent; and 4) the effect of site factors and climate interactions on outbreak dynamics of a defoliating insect. The proposed research will involve several host-agent systems and will use different tools and approaches. In one study, we will use molecular biology and chemical analysis to examine regulation of the production of defense-related compounds. In other studies, we will use tree-ring analysis to reconstruct past outbreaks which will be studied in relation to current and historic climate, with the goal of determining future risks to forest health.