A moment in time: repeat photography to understand environmental change
“Historical landscape photography is the closest thing we have to a time machine,” says Professor Timm Hoffman, director of the Plant Conservation Unit within the Department of Biological Sciences at UCT. Hoffman has been collecting historical photographs of landscapes since the late 1980s and uses them to document environmental change. As his collection grew, he ran into a storage problem which is when UCT eResearch provided him with centralised cloud-based data storage to house the collection.
Historical photograph of Silvermine Nature Reserve (Western Cape) before clearing of pine trees, taken by J Cowen in 1999, and the repeat photograph taken by J Watermeyer in 2016. Images © rePhotoSA, UCT & SANBI; CC BY-NA-SA 3.0.
Much of Hoffman’s research focuses on environmental change, and historical photographs are the best way to track that change over many years. “Once I have ascertained where the historical photograph was taken, I try and stand in the same place to retake the photograph,” says Hoffman.
“Timm was one of the first researchers to realise the benefit of centralised data storage. “The value of this service is that the storage is secure and reliable, backed up in multiple locations, and more cost- effective than a commercial cloud solution as it is centrally hosted by the institution.””
In this way he can analyse the changing landscape over the period of time linking what he sees in the landscape to climate models, so as to see if the landscape responds to the changing climate in the way the models predict. Over the years, and with the support of colleagues in the UCT Libraries and other departments, Hoffman’s collection has grown into a citizen science project called RePhotoSA. Members of the public can contribute to this project by visiting the site of existing historical photographs and taking their own images or by uploading their own historical images.
“We try to make the photos archival quality when we scan them”, says Hoffman. “But this means that a single file can be as big as 50 megabytes. When you have 20 or 30 thousand photographs, you very quickly run out of hardware space.”
“It takes only a second to take a photograph, but in that second you capture a resource so rich in information about the landscape. A collection of images can be used to build a narrative of what has driven change in that landscape over a period of time.”
“The ICTS team have been excellent in providing support for us, creating a specific drive in which we could work with the collection in the cloud”, explains Hoffman. “The space has been very stable and reliable and has been an absolute lifesaver.”
“Timm was one of the first researchers to realise the benefit of centralised data storage,” says eResearch Director, Dr Dale Peters. “The value of this service is that the storage is secure and reliable, backed up in multiple locations, and more cost- effective than a commercial cloud solution as it is centrally hosted by the institution.”
Today RePhotoSA has about 6 000 historical photographs which are accessible to the public. These however are only the photographs that are suitable for repeat photography where the exact location is known. Hoffman’s collection is close to 30 000 images in total, dating from 1876 to the year 2000.
“It takes only a second to take a photograph,” says Hoffman, “but in that second you capture a resource so rich in information about the landscape. A collection of images can be used to build a narrative of what has driven change in that landscape over a period of time.”
Historical photograph of Wagendrift Dam (KwaZulu-Natal) before it was filled, taken by D Edwards in 1961, and the repeat photograph taken by C Hundermark and H Petersen in 2019. Images © rePhotoSA, UCT & SANBI; CC BY-NA-SA 3.0.
Hoffman was also the recipient of the annual 2020 Living Planet Award from the World Wide Fund for Nature (WWF), a prestigious award given annually to exceptional South Africans who, through their contribution to conservation, inspire people to live in harmony with nature.
“Timm is not only one of South Africa’s foremost arid-zone ecologists, but is also one of the humblest and most compassionate people you will ever meet”, said Dr. Morné du Plessis, CEO of WWF South Africa. “Through this award we acknowledge an individual whose work exemplifies how conservation truly can benefit both people and nature”.
The award honours the full range of Hoffman’s work including, among others, his work around repeat photography, which has highlighted massive changes occurring in South Africa’s ecosystems over an extended period, as well as his work in the village of Paulshoek in Namaqualand, where he has contributed positively to the community.