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The Crafoord Prize 1996

The Royal Swedish Academy of Sciences awards the 1996 Crafoord Prize in the biosciences with particular emphasis on ecology to Professor Sir Robert M. May, University of Oxford, U.K., for his pioneering ecological research concerning theoretical analysis of the dynamics of populations, communities and ecosystems.
The value of the 1996 Crafoord Prize is USD 500,000. The prizewinner will receive the prize at the Academy on 19 September 1996.

Mathematical analysis facilitates our understanding of ecological patterns and processes

Robert M. May, born in 1936 in Sydney, Australia, began his career as a theoretical physicist but has become, over the last twenty-five years, the person who has exerted the greatest influence on theoretical and empirical ecological research. Through his pioneering achievements, scientists now have a better understanding of the ecological dynamics of individual populations, the interplay between different species and whole ecosystems. Furthermore, his theoretical research has been of great significance for a number of important practical problems.

May's first great contribution concerned the hotly debated question of wether stability is the cause of the diversity of ecosystems, or wether it is the other way round. May clarified that biological diversity does not automatically generate stability and that a number of different factors in combination lead to the stability of the ecosystem through various disruptions. Mays book “Stability and Complexity in Model Ecosystems" (1974) brought about a drastic change of direction in the way of viewing the interaction between different species and the reaction patterns of the ecosystem. The book stimulated innovative research contributions in a number of different fields.

May's next major contribution concerned the relationships between insects and their parasitoids, i.e. other insect species which, from the egg to adult stage live inside their hosts and gradually eat them up from inside. Using mathematical models, May was able to produce new premises for understanding how these connections between species could lead to fluctuations in the number of individuals. This in turn contributed to the development of biological control of pest insects.

This work led May to analyse more closely the conditions for different types of fluctuations in individual species, where he could demonstrate how seemingly simple and strict law-bound systems could also, under certain conditions, transform into different forms of chaos. Through these insights, May has contributed to a great degree in establishing chaos theory within a number of different areas of science.

In the young science of nature conservancy biology May's population dynamics models and theoretical analyses have come to play a fundamental role. This concerns, above all, mapping out what factors are most important for the survival possibilities of small and fragmented plant or animal populations in an environment that is exploited to an ever-increasing degree by man. Crucially, May's theoretical work has pointed at the signficance of random events within the diminishing populations, with regard to their prospects of survival for longer periods.

Another area in which May's theoretical work has been of great use concerns those factors that influence how great an extraction one can make from economically important natural populations, without harming their capability to generate yield or, in other words, harming their sustainable exploitation. These theoretical insights have been of great use not least as regards ocean fishing.

During the last ten years May has, alone or together with other co-workers, reached a leading position within two other research areas. The first concerns the ecological and epidemiological problems surrounding the spread of pathogens (illness-generating organisms, e.g. viruses and bacteria) between different host organisms. In this regard he has devoted much energy to the subject of the HIV virus in man. Apart from the obvious medical significance, May's research has contributed to focusing attention on how, for example, viruses and bacteria can function as selection factors in natural populations. Health and sickness are things that are undoubtedly important in natural plant and animal populations, as well as in man and man's domesticated animals and cultivated plants.

The other area has to do with the work of mapping out how biological diversity (biodiversity) varies in time and area (why, for example, do the tropics have a greater diversity than other areas?). To this end, May has developed new mathematical forms of approach that have a wide use. The fact is that no one knows how great the biological diversity, measured as the number of species, actually is. However, May has, on theoretical grounds, enormously increased our ability to calculate this diversity, and this in turn contributes to our understanding of how diversity has arisen, how it is distributed over different areas and why it is at present collapsing, albeit at different tempos in different areas.

May's research in a number of areas within ecological theory contitutes brilliant pioneering contributions, and his influence on today's ecological research is quite overwhelming. Ecologists of the most diverse specialisations look up to him as a model and pioneer.

Robert M. May is a professor at the Department of Zoology at the University of Oxford, England. He is also chairman of the British government's Advisory Council for Science and Technology. In Sweden he has previously been honoured with an honorary doctorate at the University of Uppsala.

Jessica Balksjö Nannini
Press Officer,
Royal Swedish Academy of Sciences
tel: +46 8 673 95 44
+46 70 673 96 50