The goal of Bill Currie's research program, growing out of ecosystem science, is to understand the organization, causal interactions, and dynamics in ecosystems and landscapes and to contribute to the new field of sustainability science. If we can capture the right complexity in our models of natural systems, we can apply this understanding to represent, study, or simulate future scenarios in linked human-natural systems. Bill teaches Modeling Coupled Human-Natural Systems, Resilience thinking, and Bio-Based Carbon Mitigation and Biofuels.

Research Interests:
The goal of my research program is to develop new knowledge and understanding about causal interactions, complexity, and dynamics in ecosystems and landscapes to contribute both to ecosystem science and to the new field of sustainability science. I have a background in ecosystem ecology, biogeochemistry, and ecosystem modeling. I am interested in taking what we know from these fields to investigate stabilities, state changes, thresholds, and other aspects of ecosystem dynamics in their linkages to human systems in the new framework of the developing field of sustainabiltiy science. I work with collaborators in SNRE, across campus, and outside UM on a range of research problems. I also work with MS and PhD students pursuing a range of topics and using a variety of approaches that include different mixtures of modeling, GIS work, and field work.

Current/Recent Research:

• Interdisciplinary research on modeling exurban sprawl and its ecological effects: As part of the SLUCE project team (Spatial Land Use Change and Ecological effects) I study the effects of growing low-density human development in previously rural landscapes. I collaborate with a team using agent-based models in a complexity-theory framework to study human preferences and decisions, spatial patterns of land cover, land markets, and land policy scenarios to understand the drivers of spatial land use / land cover change and to link this change to the land-atmosphere carbon balance.
• Wetland nutrient retention and invasive species: In collaboration with Deborah Goldberg and graduate students I am studying the two-way interactions that develop between wetland retention of elevated nutrient runoff and the increased success of invasive wetland plants and the ecosystem-community state change that seems to accompany widespread success of the invasive. We are working in coastal freshwater marshes of the Great Lakes. We are developing a new ecosystem-community model that includes spatial processes, plant competition and coexistence, and shifts in state that accompany a shift from nutrient competition to light competition.
• Forest decision making and carbon storage in the Great Lakes region. With graduate students here at Michigan and with colleagues both here and in Europe I am studying forest decision making as it relates to the combination of forest ecology, the economics of timber supply, carbon storage and carbon credits, and am currently working to understand how the use of forest products for biofuels changes the equation for economics and for atmospheric carbon mitigation.
• Large-scale 15N tracers to study forest responses to elevated N inputs and elevated CO2: I have collaborated in large-scale field manipulations at the Harvard Forest, a site in the NSF-sponsored Long-Term Ecological Research (LTER) Network (in a field study of elevated N deposition) and at the Duke Experimental Forest (in a field study of elevated CO2), where enriched isotopic N labels have been added to test hypotheses about effects of field manipulations on nitrogen cycling and carbon-nitrogen interactions. I led the development of the TRACE model (Tracer Redistributions Among Comparments in Ecosystems) to use in direct model-data comparisons in these studies.

Current/Recent Teaching:

• Ecosystem Modeling (NRE 501). This 3-credit introductory-level graduate course focuses on building simple ecosystem models, applying models to questions in ecosystem research and management, and on critically assessing the strengths and weaknesses of various types of model formulations and approaches. It is taught in a combined, interactive lecture-laboratory format using the Stella language for dynamic systems modeling.
• Modeling Coupled Human-Natural Systems (Environ 401). Human activities, decisions, and resource demands interact with ecosystem responses, stabilities, and vulnerabilities to shape large-scale environmental dynamics. This senior capstone course in the Program in the Environment (PitE) focuses on building and using models of these large-scale interactions with the goal of gaining increased insight into resource and environmental sustainability. It is taught in a hands-on, interative lecture-laboratory format using the Stella language for dynamic systems modeling.
• Seminar in Natural Resources and Environment (NRE 639): Resilience Thinking: Reading case studies of sustainability analysis in human-natural systems. In this graduate seminar students read the recent book by Walter and Salt (2006) on Resilience Thinking as well as other related papers from the scholarly literature and discuss these readings in a wide-ranging student-led format.
• Crisis, Collapse, Resilience and Renewal. This is a 2-week summer course for high school students taught as an outreach course in the Michigan Math and Science Scholars (MMSS) program at the University of Michigan. It focuses on using model building to explore stabilities, vulnerabilities, and thresholds in coupled human-natural systems, for example Easter Island, in which declining resources probably played a role in the collapse of a thriving civilization.

Selected Publications:

• Parton, William, Whendee L. Silver, Ingrid Burke, Leo Grassens, Mark E. Harmon, William S. Currie, Jennifer King, E. Carol Adair, Leslie Brandt, Steve Hart, and Becky Fasth. 2007. Global-Scale Similarities In Nitrogen Release Patterns During Long-Term Decomposition. Science 315: 361-364.

• Seidl, R., W. Rammer, D. Jäger, W. S. Currie and M. J. Lexer. 2007. Assessing trade-offs between carbon sequestration and timber production within a framework of multi-purpose forestry in Austria. Forest Ecology and Management 248:64-69.

• Chastain, Robert A. Jr., W. S. Currie, and P. A. Townsend. 2006. Carbon Sequestration and Nutrient Cycling Implications of the Evergreen Understory Layer in Appalachian Forests. Forest Ecology and Management 231: 63-77.

• Currie, W. S. and K. Bergen. 2008. Ecosystems: Forest: Temperate. In S. Jorgensen (Ed.), Encyclopedia of Ecology. Elsevier.

• Aber, J. W. Currie, M. Castro, M. Martin, and S. Ollinger. 2004. Synthesis and Extrapolation: Models, Remote Sensing and Regional Analysis. Chapter 17 in: Foster, D. and J. Aber (Eds.) Forests in Time: The Environmental Consequences of 1,000 years of Change in New England. New Haven: Yale University Press, p. 338-362.

• Johnston, C. A., D. D. Breshears, Z. G. Cardon, et al. 2004. The fronteir below: Carbon cycling in soil. Frontiers in Ecology and Environment 10:522-528.

• Currie, W. S., K. J. Nadelhoffer, and J. D. Aber. 2004. Redistribution of 15N tracers highlight turnover and replenishment of mineral soil N as a long-term control on forest C balance. Forest Ecology and Management 196:109-127.
• Yanai, R. D., W. S. Currie, and C. L. Goodale. 2003. Soil carbon dynamics following forest harvest: an ecosystem paradigm reconsidered. Ecosystems 6:197-212.
• Currie, W. S. and K. J. Nadelhoffer. 2002. The imprint of land use history: Patterns of carbon and nitrogen in downed woody debris at the Harvard Forest. Ecosystems, 5(5):446-460.
• Currie, W. S. 1999. The responsive C and N biogeochemistry of the temperate forest floor. Trends in Ecology and Evolution 14:316-320.
• Moorhead, D., W. S. Currie, E. Rastetter, W. Parton, and M. Harmon. 1999. Climate and litter quality controls on decomposition: An analysis of modeling approaches. Global Biogeochemical Cycles 13:575-589.
• Aber, J. D., W. H. McDowell, K. J. Nadelhoffer, A. Magill, G. Bernston, M. Kamakea, S. G. McNulty, W. S. Currie, L. Rustad, and I. Fernandez. 1998. Nitrogen saturation in temperate forest ecosystems: Hypotheses revisited. BioScience 48:921-934.
• Currie, W. S., J. D. Aber, W. H. McDowell, R. D. Boone, and A. H. Magill. 1996. Vertical transport of dissolved organic C and N under long-term N amendments in pine and hardwood forests. Biogeochemistry 35:471-505.