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Robert May Receives Crafoord Prize Simon A. Levin

Robert McCredie May but none has Of all the areas of application of mathematics had greater in- to , ecology has by far the longest and fluence than richest history. Through the efforts of Alfred Robert May, Lotka and Vito Volterra, a framework was in- who has led by troduced nearly a century ago for the consider- example in ation of the dynamics of interacting species, demonstrating and many thousands of papers have been in- that mathe- spired by those seminal works. But whereas the matical ecol- master, Volterra, already a distinguished math- ogy must be a ematician, was inspired by data—the fluctua- science, seek- tions of the Adriatic fisheries—while producing ing patterns in innovative mathematics, too many of the pa- data and being pers that followed were totally divorced from challenged data and were sterile exercises in mathematics constantly by with little to contribute to either discipline. In observations. the half century that followed Volterra’s work, May began his career as an astrophysicist the discipline had stagnated, and it is difficult and plasma physicist; that he later became pres- to point to any major contributions over that very ident of the British Ecological Society and is long period of time. today Chief Scientist of Great Britain is testimony The situation is dramatically different today. to his commitment to the scientific challenges Mathematical ecology is a vibrant and exciting of his adopted discipline. Indeed, May had be- area of research, with strong ties to data and with come quite a distinguished physicist by the age deep mathematical content, and one of the major of thirty-three, holding a “Personal Chair” at figures in effecting that transformation is Sir Sydney University. There, influenced by the em- Robert May, winner of the 1996 Crafoord Prize. inent Australian ecologist L. C. Birch, May became May’s contributions are stunning in their depth fascinated with the problems of the biological and quantity, and he has influenced the devel- world. He traveled to Princeton to spend a leave opment of the entire subject of ecology funda- at the Institute of Advanced Study in 1972, where mentally while making profound contributions he began a happy fellowship and eventual col- to mathematics; the latter influences were rec- laboration with Robert MacArthur, the leading ognized in his selection to give the AMS’s Gibbs theorist among ecologists in the world at that Lecture in 1994. Mathematical ecology thrives time. From that interaction emerged May’s first today because it has become a part of the sub- major contribution to ecology, his exploration ject of ecology rather than a commentary on it. of the relationship between complexity and sta- Many have contributed to that metamorphosis, bility in ecological systems. It was taken for granted among many ecologists of the day that Simon A. Levin is in the Department of Ecology and Evo- more diverse systems were necessarily more lutionary Biology at Princeton University. His e-mail stable. May, through a brilliant series of inves- address is [email protected] tigations of models of systems of differing com-

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About the Prize The Royal Swedish Academy of Sciences has announced that its els. Bob May and I gave lectures back-to-back at 1996 Crafoord Prize in the biosciences, with particular emphasis Maryland in 1974, where May presented his find- on ecology, has been awarded to Sir Robert M. May of Oxford Uni- ings. Jim Yorke, who had invited us both to versity. May was cited “for his pioneering ecological research speak, leaped to his feet excitedly to point out concerning theoretical analysis of the dynamics of populations, the similarity of the two pieces of work and to communities and ecosystems.” The Crafoord Prize, which carries add some insights of his own. I believe that this a value of $500,000, will be presented at the Academy in Stock- was the first point of contact they had on this holm on September 19, 1996. topic and that it was a milestone in blending the Previous winners of the Crafoord Prize include separate trains of research. May’s research ac- of the Courant Institute of Mathematical Sciences, who received complishments are so many that space does not the prize in 1982. of the Institute for Advanced Study permit me to catalogue them, but I would be re- and Alexandre Grothendieck of the University of Montpellier in miss if I ignored his profound influence on the France shared the prize in 1988; in a highly publicized episode, study of infectious diseases. Shortly after his suc- Grothendieck turned down his half of the prize. In 1994 the cess with chaos, May began his most successful Crafoord Prize was awarded jointly to Simon K. Donaldson of Ox- collaboration, with the British parasitologist Roy ford University and S.-T. Yau of Harvard University. Anderson. Anderson, equally remarkable in his Holger Crafoord, a Swedish industrialist who made his fortune own right, also came from a strong background in pulp and paper products and in artificial kidneys, established in quantitative methods, and the partnership the Holger and Anna-Greta Crafoord Prizes for basic research in could hardly have been more complementary at several fields not covered by the Nobel Prizes: mathematics, as- either a personal or a professional level. An- tronomy, the geosciences, and the biosciences. Each year the Acad- derson and May rewrote the subject of mathe- emy designates an area within the field being honored that year matical epidemiology, which also had a long and and chooses one or more prizewinners who have been influen- impressive history. In their hands, epidemiology tial in that area. and ecology became inseparable, and their work —Allyn Jackson has had profound influence among both math- ematicians and practitioners, deeply influencing thinking and practice regarding such funda- plexity, showed that the issue was much more mental issues as vaccination strategies for in- complex than had been realized, destabilizing the fectious diseases and the interactions between prevailing dogma. Work with MacArthur on the HIV and the immune system. limits to how many species could be packed into May’s contributions and influence continue systems over evolutionary and ecological time unabated, even as he has taken on heavy ad- complemented this work and led to his influ- ministrative responsibilities in the most impor- ential Princeton Monograph on Complexity and tant scientific position in Britain. He left Prince- Stability in 1974. Upon Robert MacArthur’s un- ton for Oxford in 1988 (to my gain, given the timely death in 1973, May was selected to replace vacancy thereby created here), but remains a him as professor of zoology at Princeton; he Visiting Professor at Princeton. The roots he de- later (in 1984) won the award established by the veloped there have surely helped to shape his Ecological Society of America to honor career, just as he helped to shape biology at MacArthur’s name. Princeton. His great interest in biodiversity found At Princeton, May continued his fundamen- fertile soil in New Jersey and led to his involve- tal contributions to ecology with a long series of ment with efforts associated with the dramatic papers, but undoubtedly, his most influential losses of the biodiversity of the planet. He has contribution to science in this period was his been on advisory councils and boards for the recognition of the ubiquity of chaotic dynamics World Wildlife Fund, the International Whaling in the most commonly used nonlinear models Commission, the Marine Mammals Commission, for population growth. Although similar ideas the Society for Conservation Biology, and trustee were being explored in other disciplines, May’s of the World Wide Fund for Nature, the Royal investigation of the behavior of one-dimensional Botanic Gardens, and the Natural History Mu- maps became one of the few places in biology seum. In recent years he has also made funda- where theoretical research found its way back mental contributions to the science of conser- into the core of mathematics to influence the de- vation biology, winning the inaugural Marsh velopment of the subject. Lorenz had published Prize for Conservation Science in 1992. his observations on weather models a few years Sir Robert May has had a deep influence on before, Ruelle and Takens had presented their the maturation of ecology as a science and on ideas on turbulence, and Gollub and Swinney had the ecology of science. It is a tribute both to his performed their critical experiments. This led Jim own contributions and to the subject that he Yorke to coin the term chaos and to publish his helped transform that he is the recipient of the analyses at virtually the same time that May was Crafoord Prize for 1996. investigating similar behavior in population mod-