On 8 December 2022, a longtime employee and friend of the CSIR, Prof. David Le Maitre, passed away. His friends, family and former CSIR colleagues and experts in his field paid their respects during a memorial service held on 21 January 2023 in Jonkershoek, Stellenbosch.

Le Maitre was employed at the organisation for 41 years, during which time he played a leading role in investigating the impacts of ecosystem change on socioeconomic benefits, focusing especially on invasive alien plant species ecology and impacts, landscape hydrology, ecosystem infrastructure protection, and wildfire risks in the context of climate change.

He first joined the staff of the Jonkershoek Forestry Research Centre as a research officer in 1979, after graduating with his forestry degree from Stellenbosch University. His initial research interest was in the effects of fire on fynbos ecosystems, and he went on to receive his MSc and PhD degrees in plant ecology at the University of Cape Town. With the demise of the South African Forestry Research Institute at the time, Le Maitre and his colleagues were absorbed by the CSIR in 1990, and he remained with the organisation until his retirement on 31 October 2020. Thereafter, he rejoined the CSIR until 31 March 2021 on a five-month contract. Even after his retirement, Le Maitre remained close with CSIR colleagues and gave input on various projects when asked. Specifically, he remained involved in mentorship and project work with his colleagues in the Biodiversity and Ecosystem Services Research Group.

During the memorial service, former CSIR colleague Prof. Brian van Wilgen described him as “An unassuming scientist who made significant contributions in his field.” He went on to say, “Although his early career focused on fire ecology, Le Maitre’s most notable contributions came from switching his focus to the effects of vegetation cover on water resources.”

Le Maitre was a brilliant scientist and played a significant role, leading a team that developed models to estimate the reductions of surface water runoff as a result of the invasion of catchments by alien trees, which led to and supported the development of the South African government’s world-recognised Working for Water Programme.

Dr Lindie Smith-Adao remembers Le Maitre as a colleague and friend and says, “It was such a privilege and honour to work with Le Maitre during my 18 years at the CSIR. He was an inspiration in my life, and I will never forget the valuable lessons he taught me.”

Le Maitre’s scientific contributions were vast and impactful. He co-authored over 200 publications, including papers in peer-reviewed journals, scientific book chapters, and policy and management-relevant reports. His work has been cited over 13 000 times, with more than 20 papers attracting over 200 citations each. His h-score at the time of his passing was 54. In October last year, Le Maitre’s contributions were recognised with the awarding of an Eco-Logic gold medal in the category of water conservation.

Le Maitre also contributed substantially to the identification of strategic water resource areas in South Africa – which produce a disproportionate amount of the country’s water. Just 10% of the country's land surface area generates 50% of its surface runoff and most of its groundwater recharge. This understanding has formed the basis for prioritising and managing land to protect and enhance water resources (i.e., approximately 13% of the area is formally protected). “His dedicated work on these topics over the past four decades has resulted in a rich contribution to the literature on water conservation in South Africa. Its impact and influence will remain relevant for many years to come,” Van Wilgen shared.

Le Maitre was a valued member of the CSIR’s Sustainable Ecosystems Impact Area and participated in projects across research groups. His broad experience and deep knowledge of ecosystem function and plant species biology will be missed by his colleagues and friends at the CSIR.

The CSIR extends its heartfelt sympathy and support to his loved ones.