Multi-Agent Models of Land Cover/Land Use Dynamics in the Northern Ecuadorian Amazon: Coupling Human & Natural Systems through Pattern-Process Relations and Spatial Simulations
Richard E. Bilsborrow University of North Carolina (US-PI)
Agent based models examine the basic characteristics and activities of individual agents (e.g., households) as the basic building blocks. Agents differ in important characteristics and their interactions are dynamic, in that, the characteristics of the agents change over time as the agents adapt to their environment, learn from experiences through feedbacks, or “die” as they fail to alter behavior relative to new conditions and/or factors. The dynamics that describe how the system changes are generally nonlinear, sometimes even chaotic, and seldom in any long-term equilibrium. Individual agents may be organized into groups or hierarchies that may influence how the underlying system evolves over time. Complex adaptive systems are self-organized systems that combine local processes to produce holistic systems (Bak 1998). They are emergent and self organizing in that macro-level behaviors emerge from the actions of individual agents as agents learn through experiences and change and develop feedbacks with finer scale building blocks.
It is now well recognized that at local, regional, and global scales land use changes are significantly altering land cover, perhaps at an accelerating pace. This transformation of the Earth’s surface, particularly through deforestation, agricultural extensification, secondary forest succession, and urbanization, is linked to a variety of scientific and policy issues that revolve around the human dimensions of LCLU change and its causes and consequences of such changes. As frontier environments in the Ecuadorian Amazon and elsewhere within the Amazon Basin are developed, land is transformed, and land use processes altered that affect the vulnerability and sustainability of ecological and social systems. LCLU dynamics change the nature of population-environment relationships at the frontier and alter the feedbacks that subsequently influence human decision-making and future trajectories of land use. Frontiers are important because the typical agricultural transformation that occurs there significantly impacts global land cover, which in turn, affects global health, climate change, and human behavior and welfare. Feedbacks among people, place, and the environment constrain or even reverse some of the original changes in LCLU through system dynamics. In this way, properties emerging from local nonlinear feedbacks constrain the evolving patterns of land use. Critical points in the spatial structure of LCLU patterns and feedbacks can produce a system with identifiable future alternative states in which instabilities can “flip” a system into another regime of behavior by changing the variables and processes that control LCLU change. Endogenous and exogenous factors combine in complex ways to alter the vulnerability and resilience of system components.
We will use (a) an assembled satellite image time-series to characterize LCLU change patterns and trajectories in the NEA, (b) ecological pattern metrics to describe the spatial structure of LCLU change at landscape, class, and patch levels, (c) GIS to characterize geographic accessibility and resource endowments of land parcels being transformed from forest to crops, pasture, secondary forest, and urban uses, (d) socio-economic, demographic, and ethnographic survey data to characterize households, communities, and indigenous groups, (e) logistic regression to understand the distal and proximate causes and consequences of LCLU change and their space-time lags, (f) multi-level models to associate community characteristics to household decision-making about land use at the farm level, and (g) agent based models that rely upon characteristics of households as agents that interact, evolve, and adapt to changing landscape patterns. We will integrate exogenous and endogenous drivers to represent a complex and diverse set of forces and factors operating in the NEA, which together affect LCLU change patterns in fundamental ways in the broader Amazon Basin. We will examine the following set of questions through this proposed research:
· What are the linkages among people, place, and environment on the frontier, and what are the feedback mechanisms between population and the environment that influence LCLU change patterns?
· How are demographic and other aspects of human behavior changing frontier settings, what are the emergent properties that cause LCLU change to occur, and what are the consequences of LCLU change on the integrity of interconnected social and ecological systems within the NEA and the broader Amazon Basin?
· What are the plausible scenarios of future LCLU change, what are their policy implications, and what tools and approaches can best be used to understand a region that is undergoing dramatic change through the actions and interactions of key stakeholder groups who are interacting in complex ways?
· Do social, biophysical, and geographical properties of the couple human-environment system that operate in the Amazon Basin emerge from local nonlinear feedbacks that constrain the evolving patterns of land use?