Biocomplexity: Integrating Models of Natural and Human Dynamics in Forest Landscapes Across Scales and Cultures

Few ecosystems are now free of extensive human influence, but the ways that human activity affects ecosystems such systems and their reciprocal effects on human behavior are poorly understood. The major objective of this research project is to develop integrated models that couple forest ecosystem dynamics to human decision making.

The project focuses on two major components and their interaction: (1) the structure and functions of forest ecosystems; and (2) the human behaviors that affect forest ecosystem structure and functions. The models of forest structure will be hierarchically arrayed, beginning with the dynamics of tree growth and distribution and work up to the stand and landscape scales. Changes in forest cover affect ecological processes and functions, leading to predictable changes in water quantity and quality. Human behaviors will be simulated using multi-agent models, and they will be coupled to the forest models through linkages that describe different forms of disturbance of human activities on forest and hydrologic system functions and by receiving feedbacks about the effects of such actions from the forest and hydrological models. Information about the values driving human decision making will be obtained through empirical social-science research, including survey questionnaires.

The dynamics of the coupled natural and human systems will be analyzed mathematically to identify complex behavior (such as oscillations and "chaos") resulting from the interaction of the human and natural systems. The project will examine natural-human system interactions in four study areas: the Trinity River Greenbelt corridor and the Big Thicket in Texas and the Caparo Forest and Imataca Reserve in Venezuela. Considerable data already has been gathered for the first of these sites, permitting it to serve as a test bed for the project. This two-year pilot study will test the feasibility of modeling forest dynamics as they are reciprocally influenced by human decision making, and it will begin the extension of the research to the larger study areas. Application of the models to the sites in Venezuela, which are very different culturally and ecologically, will demonstrate the generality of this approach to understanding coupled human and natural systems.

Results of this research will provide a better quantitative understanding of the interplay between human actions and forest dynamics. This enhanced understanding will give landowners, other stakeholders, and policy makers reliable information about the impact of their decisions on the future composition, structure, and functionality of local ecosystems. It will thereby facilitate a more informed analysis of the long-term consequences of private choices and public policies on the natural systems in which human systems are embedded and with which they interact. This project is supported by an award resulting from the FY 2002 special competition in Biocomplexity in the Environment focusing on the Dynamics of Coupled Natural and Human Systems.