dynamics of coupled human-natural systems
To solve
contemporary problems such as ensuring food security for a particular region or
for the globe, we need more basic research on the interactions between natural
resource dynamics, human population growth, and social factors such as
technology, culture, politics, and economics. I couple ecological, demographic, and social models to examine the
interactions between environment, food supply, human demography, and human
decision-making. I have focused on preindustrial
agricultural societies, whose dynamics are closely tied to their local
environment, but the principles apply to hunter-gatherer societies and
ultimately to modern industrial societies.
This work has three components: agroecosystem modeling, demographic modeling, and behavioral/political/economic modeling.
►Sophisticated models of agroecosystem dynamics are widely available. The core plant-soil dynamics form a
stochastic system comprising climate, soil properties, and other environmental
characteristics. The output is a time
series of food production (e.g, Lee et al. 2006) that can be coupled to
food-dependent demographic models.
►I have developed a general model
framework for food-dependent
demography (Lee and Tuljapurkar 2008 ) that uses food as the explicit
link between population age structure (labor supply) and population vital rates
(survival and reproduction). This
framework provides biological mechanism to human demography, and easily
accommodates different physical or biological environments (via parameters such
as agricultural yield and maximal survival rates) as well as different
cultural, social, or technological milieux (via parameters such as age-specific
labor efficiency and the sensitivity of fertility rates to food shortage).
►What are the consequences of
environment-dependent population for social, political, and economic choices? Application of the coupled agroecosystem/demographic
models to a spatiotemporally variable landscape in
