Dame Georgina Mace obituary

Science tells us the names of more than 32,000 species threatened with extinction, including the European hamster, the North Atlantic right whale and the golden bamboo lemur. We know this thanks to the work of Georgina Mace, who has died aged 67 of cancer: she was the force behind the red list of threatened species that has been the foundation of conservation policy since 1996.

For decades the International Union for Conservation of Nature’s red list, created in 1964, was a haphazard affair – there were no criteria for judging what should go on the list, and the will of politicians and personalities held a lot of sway. Charismatic species such as chimpanzees and leopards were the focus of emotive conservation efforts while thousands of less glamorous life forms were slipping under the radar.

Political action required robust numbers and the credibility of the IUCN list was at risk. In 1987 Ulysses Seal, a well-regarded American conservationist who had worked with Mace on an IUCN species survival commission, suggested she should be the person to sort it out.

As a young and relatively unknown population biologist working at the UK Zoo Federation, Mace was regarded as a bizarre choice. Partly because of Seal’s standing, and partly because no one could come up with a better idea, Mace – with no prior training – was asked to take the lead.

With characteristic modesty, she said her team “made it up as we went along”, but the changes were radical. She moved away from qualitative data to quantitative data – species were only included in the threatened categories if they satisfied criteria such as their population size, habitat fragmentation and population trends.

Many feared the new system would prevent their favourite species from continuing to qualify as threatened. For Mace, nature conservation was about making ecosystems resilient and that meant protecting overall diversity – she was unemotional about what categories species ended up in and refused to make shabby compromises with people in high places.

In 1991, alongside the American biologist Russell Lande, she published a paper, Assessing Extinction Threats – Towards a Re-evaluation of the IUCN Threatened Species Categories. Then, in the backrooms of the Zoological Society of London, Mace organised workshops with a variety of experts to make sure their unified threat classification system worked for all species. During pre-internet times, correspondence was done via letters and faxes, with meetings running late into the night. She was never paid by the IUCN for her work.

In 1996, the first red list based on the new criteria was produced. Aquatic organisms were key beneficiaries – cod and bluefin tuna were found to be as threatened as the African elephant. Many government fishery agencies were furious because they had to limit catches on certain species, as the strength and transparency of the system meant governments were more willing to invest in nature conservation.

Mace championed the idea that social justice and biodiversity are connected. She was skilful at distilling complex principles into pithy statements that would resonate with people, and helped to create the premise of “natural capital”, recognising that the environment is not just a source of wonder and beauty but provides value that sustains economies and lives globally. Mace’s work has had a significant influence on driving the government’s current 25-year environment plan and future rules to assess public spending.

There are an estimated 1m threatened species and the red list grows as we get more data on them. National red lists are now used in more than 100 countries as an indicator of biodiversity trends. The Global Environment Facility looks at the red list to determine how much money each country will receive for conservation and the corporate sector use it to look at the environmental impacts of development and infrastructure projects.

Born in Lewisham, south-east London, Georgina was one of three children of Benjamin Mace, a consultant rheumatologist at Lewisham hospital, and Josephine (nee Bruce), a medical artist and illustrator. She was a studious child and her first prize (of many) was a children’s newspaper handwriting competition, in 1958.

From the City of London school for girls, she went to Liverpool University and gained a degree in zoology (1976), followed by a PhD in the evolution of small mammals at Sussex University (1979). After brief postdoctoral work in Washington DC and Newcastle upon Tyne she moved back to London.

In 1985 she married Rod Evans, a planning inspector, and had three children. They settled in Kentish Town, north London. Although early on she toyed with becoming a computer programmer, science was her calling.

In 2005 Mace led the biodiversity input into the Millennium Ecosystems Assessment, which assessed the human impact on the environment and the benefits gained by humans from ecosystems. She was the first female president of the British Ecological Society (BES), a fellow of the Royal Society and won a number of prizes, including a President’s medal from the BES, the International Cosmos prize and the Heineken prize for environmental science. Mace also helped improve the Living Planet Index, which was subsequently used to develop the Convention on Biological Diversity’s 2010 Aichi targets.

The first president of the Society for Conservation Biology from outside North America, she was appointed DBE in 2016. She worked on the adaptation committee of the UK government’s committee on climate change and oversaw the 2018 report on land and how it could contribute to climate mitigation and adaptation. From 2012 she was professor of biodiversity and ecosystems at University College London.

Many of Mace’s students went on to hold critical positions in academia and conservation. Colleagues remember her warmth, respect for others and no-nonsense attitude. She had a wicked sense of humour and was a humble leader. A former student said she was “always the cleverest person in the room … [who] never wanted to show that she was the cleverest person in the room”.

Despite the gloomy outlook for global biodiversity she believed in the power of problem-solving – in a 2009 interview she said “all the evidence to date is that when societies put their mind to solving a problem, they can generally do it”.

On 10 September she had a paper published in Nature that showed there was still a chance to “bend the curve” on nature restoration so that biodiversity can recover. The week she died, she contributed to a Royal Society biodiversity group.

Mace was an enthusiastic croquet player and enjoyed watching athletics, rugby and cricket. Towards the end of her life she and Rod moved to a house in Charlbury, Oxfordshire, that was by a river and had views over the countryside.

She is survived by Rod, her children, Ben, Emma and Kate, and a granddaughter, Harriet.