Bob May (1938-2020) provided mathematical support for the theory that species diversity is essential for maintaining the healthy ecosystems that provide humanity food, health, pleasure, and knowledgeHe died on 28 April 2020. (Guardian Obituary) (Sydney Morning Herald)

He had an amazing career spanning mathematics, chemistry, physics, chaos theory, species abundance, and estimating how much biodiversity there may be and why it maintains healthy ecosystems. A good tribute to his life with quotes from an interview is here. He applied epidemiology thinking to economics, and how banks (should) operate, saying “Science and mathematics are really no more but no less than a way of thinking clearly. There is a lot of read-across.

He published an astonishing amount, with over 1,200 publications, and was cited in the scientific literature over 150,000 times. His H-index of 175 (175 publications cited 175 times) is extraordinary. Trained as a physicist, his top-cited works were in epidemiology, species abundance and diversity, extinction rates, the stability of natural communities and chaos theory, and included the Millennium Ecosystem Assessment. A keystone work was on stability and complexity in ecosystems where he mathematically modelled the idea that more diverse ecosystems are more stable, and as species are lost the consequences are unpredictable. This theory underpins the argument that conserving biodiversity is essential for maintaining healthy ecosystems.

We met in 2011 and 2012 at his office in Oxford. I wanted to know what he thought of my findings that there were more people describing new species than ever (i.e., taxonomists), that this number was increasing faster than the number of new species being described (decreasing ‘species catch per person’ on average), and my revised estimates of how many species existed. He expressed surprise at the first point because it conflicted with widespread ‘opinion’ and he agreed it significantly changed our perspective on how well species have been described and the state of taxonomy as a discipline (it is flourishing not dying). A consequence of this reduced estimate of global species richness was that extinction rates needed to be reconsidered.

We now realised extinction estimates were on shakier ground than species richness estimates! I questioned the basis for his extinction estimates in the Millenium Ecosystem Assessment because he was comparing different taxa, sampled using different methods, in different time periods, and whose extinctions had different causes. We diplomatically included these caveats in a review and follow-up papers we wrote together with Nigel Stork (also an expert in taxonomy, richness estimates, and a critic of extinction rates). It is surprising that many people ignore these more reasoned assessments of species richness and extinction rates and choose the most dramatic ones they can find, perpetuating incorrect information and compassion fatigue.

From an interview, his advice for choosing a career “Then I had a decision to make: ‘Am I going to go on and do physics honours and think about a life in academia, or am I going to go back to engineering and think about a life doing something down to earth and much more focused?’ ….[you were Practical]  ……To a degree that I think too many graduate students these days don’t appreciate. At that time I was 19 but I recognised that there is no recipe for being a successful creative scientist. It is much easier to be a good, useful, professional, employable engineer than to embark on this journey into the unknown. Perhaps it is an unkind observation but I also saw that science is a profession that makes tough judgements about you and has clear hierarchies. So you are going into something where you have no guarantee of success and it is not all that well paid. ………….., you also need to be able to perceive the opportunity that is being offered and have the equipment to follow it. And the ability to recognise something that might be a chance, but where you don’t have the techniques and the equipment to follow it. I don’t, on the other hand, see it as being prepared to look for luck. I see it as happenstance. Sometimes you are asked for advice for young scientists, and I look at some of the interesting classic things. Peter Medawar and The Art of the Soluble said ‘Don’t do anything unless you can be sure it’s going to work out’. I am rather unkindly in the habit of saying, ‘What boring advice. What a dreary way to go’. Jim Watson said ‘avoid stupid people’. A great idea, but how do you do it? It is not useful advice. Mine is equally useless – it is ‘be lucky’.”

I suggest that he was not only lucky but he loved solving real-world problems (not following well-trodden paths), was a skilled mathematician, an excellent communicator, and worked very hard (perhaps ten times more publications than most full-time scientists may achieve in a lifetime). Of Irish and Scottish-Australian parents, he grew up and studied in Australia before working in Princeton for 16 years and then Oxford. He was neither privileged nor unprivileged and made the best of opportunities in his scientific network. He kept fit — he enjoyed lunchtime jogs around the park with John Krebs and had the physical build of a regular runner. He never aspired to positions of power or wealth and struck me as leading a balanced and reasonably simple life, occupying his time with science and family. Reading the interview it seems a key ingredient in his success was he loved doing the work he did (which makes working hard fun) and had a happy marriage, two key ingredients for a good life.


Bob May’s publications in Google ScholarObituary in The Guardian, and tribute in the Australian Academy of Sciences with interview text.

Obituaries in Nature by his long-time colleague and friend John Krebs, Trends in Ecology and Evolution by Sunetra Gupta, and PNAS (see below).

Podcast on ABC “Vale the professor of everything“.

Krebs JR, Hassell M. 2020. Robert May (1936–2020). Pioneering theoretical ecologist and outspoken government adviser. Nature 581, 261. doi: 10.1038/d41586-020-01364-y

Costello MJ, May RM, Stork NE 2013. Can we name Earth’s species before they go extinct? Science 339, 413-416. DOI: 10.1126/science.1230318

Costello MJ, May RM, Stork NE 2013. Response to Comments on “Can we name Earth’s species before they go extinct?Science 341, 237. DOI: 10.1126/science.1237381

Gupta S. 2020. Professor Lord Robert May of Oxford (1936-2020)Trends in Ecology and Evolution

Galvani A, Hastings A, Levin SA, Singer BH. 2020. Robert May, 1936–2020: A man for all disciplines. 

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