Modelling environmental effects on ecosystem productivity under diverse climates, soils and land use practices with the ecosystem simulation model ecosys

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Projections of changes in ecosystem productivity and greenhouse gas exchange under hypothesized changes in climate, disturbance, land use and soil quality are being made using process-based ecosystem simulation models. The development and testing of such models is a stated objective of national and international research projects such as the Canadian Carbon Program (CCP) and the North American Carbon Program (NACP). My research program is dedicated to the construction and testing of a comprehensive mathematical model (ecosys) of natural and managed ecosystems. This model is based upon fundamental principles in several component disciplines, including biometeorology, plant biology, plant biochemistry, agronomy, soil biology, soil physics, and soil chemistry. The innovative nature of this research lies in the integration of these principles into a single mathematical entity that can reproduce the complex behaviour of terrestrial ecosystems. The long-term objectives of my program are to provide a means to anticipate ecosystem response (changes in C, nutrient, water status) to hypothesized changes in environmental conditions (soils, climates, disturbance and land use). Within these longer-term objectives, I propose to test the simulation in ecosys of processes that control the responses of ecosystem productivity to (1) hydrology in peatlands, and (2) warming in crops. This testing will be supported by recent measurements of (1) continuous water transfer and CO2 exchange in peatlands in the CCP, and (2) controlled warming of crops under natural field conditions by the USDA-ARS. The simulation of hydrological and warming effects on productivity is based upon kinetics of basic physical and biological processes established from independent laboratory studies, but not as yet tested under field conditions. The proposed work will contribute to the predictive capability of ecosys for changes in the productivity of diverse ecosystems as affected by climate, soil quality and land use in different national research projects in which I am a principal investigator or co-investigator.