Eli Fenichel’s research approaches natural resource management and sustainability as a portfolio management problem by considering natural resources as a form of capital. He is interested in how people can and do allocate natural resources and natural resource risks through time. This leads to a strong interest in feedbacks among humans, ecosystems, and the management of coupled ecological-economic processes. His research is applied in a wide variety of systems including: natural capital valuation, fisheries, infectious disease, groundwater, tropical forests, and grasslands.