n this incites interview, Dr. Simon Levin, the George M. Moffett Professor of Biology in Princeton University’s Department of Ecology and Evolutionary Biology, discusses his highly cited work, "The problem of pattern and scale in ecology," (Ecology, 73[6]: 1943-1967, December 1992). This review has been cited 418 times to date, making it the most-cited paper of the 1990s in the field of environmental research.

Understandably, most ecological research—indeed, most research in any field—is carried out at limited scales of space, time, and organizational complexity. Yet any such study presents only a piece of the puzzle, a snapshot that is a slice of a much broader picture. It is fundamentally important to understand how one's perspective in terms of the scales chosen shapes the picture one observes, and to learn how to relate phenomena across scales. In particular, ecosystems and the biosphere are complex adaptive systems, in which patterns at one scale emerge from the interplay among processes operating on multiple scales. The great challenge for our science is to relate these scales, and in particular to understand how macroscopic phenomena emerge from the collective dynamics of heterogeneous collections of individual entities.

  What were the greatest challenges in performing and presenting your work?

Drawing together varied points of view independently derived by numerous investigators working at diverse scales of organization, and relating ecological and evolutionary points of view.

The paper was an invited paper, being based on the Robert MacArthur Award lecture of the Ecological Society of America (ESA). I received the Fourth MacArthur Award in 1990, and it was expected that I would develop my lecture for publication in Ecology, the flagship journal of the ESA.

Nothing. I am very happy with the way the lecture came out. Nearly a decade later, I developed the ideas further into a popular book, Fragile Dominion, (Fragile Dominion: Complexity and the Commons. Perseus Books, June 1999) that expresses my subsequent thinking on the subject. But without "Pattern and Scale," Fragile Dominion would not have been written.

Mainly that the insights are clearly not limited to ecological systems. Problems of pattern and scale are pervasive in science, and it is crucial that all scientists recognize the degree to which their own disciplinary biases (especially in terms of level of organization) color the way they approach their subjects, and the answers they obtain.

That all of the systems we encounter, from the cell to the biosphere, from insect societies to human societies, are complex adaptive systems in which evolutionary changes are taking place at multiple levels. What homeostasis and resiliency we may observe in societies and ecosystems are the result of evolutionary processes at lower levels, and it is essential to understand that fact if we are to maintain those systems. Global environmental problems present particular challenges to society. To sustain the services we derive from ecological systems, we must tighten feedback loops to reinforce behaviors at the microscale that are in the public interest at the macroscale. That is, we must reward individuals for behaviors that are in the common good, and assess costs to those that are not.

I was trained as a mathematician, but have worked in mathematical biology for nearly 40 years. For 27 years I was on the faculty at Cornell, primarily in the Section of Ecology and Systematics. For the last eight, I have been at Princeton, in Ecology and Evolutionary Biology, as well as in the Program in Applied and Computational Mathematics and the Princeton Environmental Institute. Especially important to me in terms of outside influences have been my involvement with the Santa Fe Institute, in Santa Fe, New Mexico; the Beijer International Institute of Ecological Economics, in Stockholm, Sweden; and the International Center for Theoretical Physics in Trieste, Italy.

Dr. Simon Levin
Princeton University
Department of Ecology and Evolutionary Biology
Princeton, NJ, USA