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Newswise — Magaliesberg - Rare-plant experts from the University of Pretoria (UP) are spearheading the reintroduction of thousands of critically endangered Magaliesberg aloe (Aloe peglerae) seedlings into the wild. The project, supported by the (BotSoc), is the first major reintroduction effort involving an endemic South African aloe species. 

The Magaliesberg aloe is a slow-growing species and is known for its spectacular red flowers. The aloe only grows on north-facing slopes of the Magaliesberg mountains to the north of Pretoria. A small population also exists around Krugersdorp in Gauteng’s West Rand. It was listed as after a survey in 2016 found its overall population numbers to have dropped by an estimated 43% within a decade, particularly because of illegal harvesting.

“The Magaliesberg aloe has a very narrow distribution range, as it is particularly well adapted to the very hot, dry conditions experienced on top of the Magaliesberg,” explains Richard Hay, curator of the and the Future Africa Indigenous and Orphan Crops Collection of the Manie van der Schijff Botanical Garden (MvdSBG) at UP, as well as BotSoc’s Conservation Project Coordinator for the Northern Region.

Hay says the idea is to continuously reintroduce young plants only into areas where the aloe once grew naturally, but no longer occurs.

“From historical records we know that this aloe used to grow on the mountain above Mamelodi. None are left at this particular location today. We therefore know that by reintroducing seedlings into the area there is no risk of interfering with the genetics of existing wild populations,” Hay explains.

Since November 2024, more than 1 500 seedlings, all the size of a R5 coin, were planted at intervals along the foothills of the Magaliesberg mountains above Mamelodi. The area is managed by the Mothong African Heritage Trust, which was founded by traditional health practitioner Dr Ephraim Cebisa Mabena to protect the natural vegetation of the mountain and to engage with the wider community about preserving the natural environment.

“The heavy rainfall over the northern parts of South Africa over December did not cause rot or in other ways damage the seedlings that we have already planted out. They all seem healthy,” Hay reports.

It will take approximately 10 years before these seedlings will flower for the first time. The replanting process is guided by best practices developed through the research of Arnold Frisby, a PhD candidate in botany at UP and curator of its cycad and indigenous plant nursery. 

“Planting seedlings within their natural distribution range in sheltered spots, for instance next to or under grasses, greatly improves their [chances of] survival,” Frisby says.

Conversations lead to conservation

The idea behind the reintroduction project was sparked through initial informal conversations about plant conservation between Hay; Jason Sampson, Head Curator of the MvdSBG; and Quinton Bean and Andy de Wet, owners of the specialist nursery The Aloe Farm near Hartbeespoort, north of Johannesburg. The Aloe Farm donated 8 000 one-year-old Magaliesberg aloe seedlings in July 2023. These were then nursed over many months in the greenhouses at the Manie van der Schiff Botanical Garden on UP’s Hatfield Campus by UP staffers, volunteers from BotSoc and the Johannesburg Succulent Society, and interns from the Tshwane University of Technology. Many of these team members later helped to replant the seedlings above Mamelodi.

Dr Martina Treurnicht, BotSoc’s national conservation project manager, says the project team is inspired by the example set by other South African plant reintroduction projects in support of the survival and persistence of critically endangered species, such as the Clanwilliam cedar tree and Cape Town’s Erica verticillata.

“Citizen science and volunteer engagement is crucial to the success of programmes aimed at ensuring the survival and persistence of species,” Dr Treurnicht says. “Volunteers play a key role in hands-on conservation, from planting initiatives to raising awareness in local communities – and it is great to see people working together for this purpose. Collectively, these efforts strengthen conservation actions, support biodiversity, and help prevent species loss, which is critical in the current biodiversity crisis where many plant species face ongoing decline in the wild.”

About The Aloe Farm’s involvement in the project, Bean says: “We strongly believe in conservation through propagation. Preserving species diversity is important. It’s the right thing to do.”

Extinction risk

“Aloe peglerae is on theof critically endangered species due to, almost exclusively, illegal collecting, rather than the impact of disturbance or development,” adds De Wet.

Sadly, the aloes seldom fare well as a garden plant, as people tend to overwater them or plant them in areas that are not optimal to their development.

“From a conservation perspective, the plants are very important sources of food to animals of the Magaliesberg during winter, when not much else flowers. Added to this, when adult plants are removed from the already small existing populations, it completely disrupts the generational recruitment of the species,” Hay notes. “I believe that all species that are part of South Africa’s important natural heritage have the right to exist, irrespective of their benefits to us or not. They exist the same way we do. It is really our duty as South Africans to protect them and to take pride in them.”

The way forward

All seedlings not yet planted out by the end of February were temporarily moved to the rooftops of UP’s Future Africa Campus.

“There they can bake in the sun until next summer, as they would in their habitat. This aligns their growth going forward more closely with their growth in nature. It will help tough tissues develop, thereby increasing resistance to aloe cancer caused by mite infections,” Hay explains.

Bigger plants that Frisby raised as part of his PhD research will be planted in the Future Africa gardens. These could flower within eight years. Seeds collected from this new satellite population will sustain efforts to continuously reintroduce the species into areas where the species is wiped out, to help establish populations of varying ages.