Saving an iconic South African plant from
extinction
Critically Endangered succulents need
our help, but how do we ensure that our efforts bear fruit?
ARNOLD FRISBY, MIA MOMBERG and PETER LE
ROUX
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| Image 1: The iconic Magaliesberg Aloe in habitat. (Photo. A. W. Frisby) |
THE MAGALIESBERG ALOE
The Magaliesberg Aloe (Aloe peglerae) is one of the
most iconic South African plant species and one of the most sought after by
aloe and succulent collectors. This is thanks to its unique appearance that
changes through the seasons and is crowned by one of the most spectacular
floral displays in the succulent kingdom, setting the veld alight in the gloomy
highveld winters with densely packed rich red flowers. Alas, the combination of
human greed and the beauty of this species has sent it to the brink of extinction
in the wild.
CRITICALLY ENDANGERED
Poachers and uninformed plant collectors have reduced this
species’ numbers in the wild dramatically over the past twenty years, likely by
over 50%. If this rate of decline continues, the species will have lost 80% of
its population by 2070. The main threat faced by the Magaliesberg Aloe is
illegal harvesting for the horticultural trade, that includes the collection of
fruit (and seeds) from plants in the wild. Harvesting for medicinal purposes
and habitat destruction for developments are additional threats, albeit minor
compared to the threat of poaching. The slow-growing nature of the species,
with a generation time of 30-40 years, and low levels of recruitment (plants
that germinate in habitat) mean that even minor levels of poaching and seed harvesting
will have dire conservation consequences. Because of the threats faced by the
Magaliesberg Aloe, it has been classified as Critically Endangered on the Red
List of South African Plants.
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| Image 2: The Magaliesberg Aloe showing its winter colours and closed leaf ball, together with unripe fruit. (Photo. A. W. Frisby) |
HABITAT SPECIALIST
The threats faced by the Magaliesberg Aloe are compounded by its specific habitat requirements. It is restricted to the upper rocky north-facing slopes of the Magaliesberg and Witwatersrand in the Gauteng and North-West provinces. The habitat is dominated by grasslands that receive summer rainfall. The soils are very shallow (no deeper than 10 cm), which means that extremely good drainage is essential for the species, a fact that is often overlooked by poachers. Thus, most poached plants die in cultivation due to inappropriate soil and moisture conditions. This aloe is also adapted to fire, which is common in its habitat, and withstands burns by “closing” its leaves into a compact ball in winter, protecting its growth point deep within itself. Long periods without fire due to poor veld management could lead to bush encroachment that would have obvious negative effects on the species. In areas such as this, an eventual and inevitable fire would result in more intense fires due to higher fuel loads that these plants, and particularly their seedlings, may not be able to tolerate. The Magaliesberg Aloe is a habitat specialist that requires a fine balance of factors to persist in nature.
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| Image 3: A group of one-year-old seedlings ready for transplantation. (Photo. A. W. Frisby) |
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| Image 4: A seedling with roots growing through a biodegradable gusset bag that protects the roots from damage during transplantation. (Photo. A. W. Frisby) |
A PLAN OF ACTION
The ongoing decline of South Africa’s plant species,
particularly its rare and endangered succulents, is disheartening to all nature
lovers. But it is not all doom and gloom. One way to stem the extinction tide
is the practice of Conservation Translocations as defined by The International
Union for Conservation of Nature (IUCN). Conservation Translocations broadly
refer to active efforts to increase the numbers of threatened life forms, such
as plants, in their natural habitats or conserved areas deemed to be
ecologically suitable. Although this concept is by no means new, it is not
often undertaken, particularly in Africa, because of various constraints
including a lack of resources and poor knowledge of species’ biological and
ecological requirements. Additionally, the remote nature of many threatened
species’ habitats means that little to no care can be given once they are
planted or released, resulting in many “failures” and wasted resources.
Therefore, if efforts to translocate species are to be undertaken in such a way
that resources and effort is rewarded, best practice protocols need to be made
available to conservation organisations. This is why we hatched a plan in 2019
to do just that for the Magaliesberg Aloe.
GROW, GROW, GROW, PLANT, PLANT, PLANT!
We identified two
sites in the Magaliesberg in the North-West Province where a good number of Aloe
peglerae were present, and obtained permits that allowed us to collect a
limited number of seeds. These seeds were planted in specialised containers and
germinated in a greenhouse at the University of Pretoria in December 2019, and
grown for one year. During this time half of the seedlings were treated with
drought-tolerance-enhancing compounds. Crucially, all the seedlings were
regularly dosed with pesticides and fungicides. One cannot risk taking any
nasties back into their habitat with them. In December 2020, the dimensions of
all the seedlings were measured and recorded (yes, the seedlings went through
lockdown too). At this stage, the first batch were ready to plant back into
their habitat. The timing of their planting coincided with the start of
reliable rains. The seedlings hiked back up the mountain with us after a drive
from Pretoria, and were carefully planted in selected locations. Specifically,
half were planted in the shade of a grass tussock, and the other half in the
open. The rationale behind these methods was to identify the best planting conditions
maximise the aloes chances of survival and growth. Additionally, the effect of
the chemical treatment on survival and growth was also being investigated. The
process described above was repeated in December 2021 and December 2022 with
additional batches of one-year-old seedlings.
MEASURE, MEASURE, MEASURE?
During 2021 and up to the end of 2023, all the seedlings were
revisited three times a year and scored based on their condition as well as
remeasured. Although, “all the seedlings” is not quite accurate, as some had
disappeared without a trace! Devastatingly, many had also burnt in an unplanned
veld-fire. Some showed signs of animal damage. Camera traps later showed
baboons passing through the sites and it was clear that some were curious (or
bored?), and had simply uprooted seedlings. We feared the worst but continued
our trips to the sites and before we knew it, three years of monitoring had passed,
and it was time to crunch the numbers.
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| Image 5: Arnold
Frisby and Prof. Peter le Roux finding suitable places to plant the seedlings. (Photo: M. Momberg) |
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| Image 6: Dr. Mia Momberg relocating transplanted seedlings after an unexpected fire. (Photo: A. W. Frisby) |
A RAY OF HOPE
Although survival rates dropped year by year, we were
delighted to see that almost all the seedlings that had burnt had fully
recovered and had grown a lot. It was also clear that once the seedlings
reached a certain size, their short-term survival became more likely. Similarly,
animal damage stopped once the seedlings were big enough (and well rooted). The
chemical treatment had a positive effect on the growth of the seedlings. The
size when they were planted also had a positive effect on their survival: the
bigger the better. However, one factor was abundantly clear: seedlings planted
in the shade of grass clumps had much higher survival and growth rates than
those planted in full sun. This result made us ecstatic, and it conformed with
a well-known ecological phenomenon known as the “nurse plant theory” where
proximity between plants can have beneficial effects on one, or both plants
involved. In this case, the aloe seedlings were clearly benefitting from the
shade (and possibly higher moisture and nutrient levels) provided by the
grasses. In summary, it seemed that there is a clear way to translocate the
Magaliesberg Aloe in a way that maximises their chances of survival without
further human intervention, despite the harsh nature of their natural habitat.
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| Image 7a: a seedling planted in December 2020. (Photo: A. W. Frisby) |
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| Image 7b: the same seedling three years later, in December 2023. (Photo: A. W. Frisby) |
A PLAN FOR THE FUTURE
In a recently published scientific article, we provide a
protocol that can be followed for future translocations of the Magaliesberg
Aloe. Our hope is that insights gained from this project will aid in informing
similar efforts for other threatened aloes and even other succulent genera.
Indeed, well over a quarter of Aloe species in South Africa are of
conservation concern and in need of similar translocation efforts. We do offer
a word of caution: three years of monitoring felt long to us but this is a short
period of time for plants surviving the rigours of nature! Future
translocations should also consider the genetic diversity of the species, as
some populations may be distinct and could be “contaminated” by the introduction
of unrelated individuals. In terms of the long-term success of this project, we
are to continue monitoring and expect some of the surviving seedlings to die
before reaching maturity but hopefully, in time, many will bear fruit.
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| Image 8: A seedling planted on the eastern side of a grass, where it benefitted from the nurse plant effect. (Photo: A. W. Frisby) |
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| Image 9: A majestic clump of the Magaliesberg Aloe, lighting up the winter landscape. (Photo: A. W. Frisby) |
A WORD OF THANKS
This for fulfilling and insightful project would not have
been possible without support from the following people and organisations:
The Botanical Education Trust
Botanical Society of South Africa (BOTSOC)
The Richard Watmough Magaliesberg Conservation Fund
The Mountain Club of South Africa: Magaliesberg Section
Prof. Stefan Neser
ADDITIONAL READING
Frisby,
A.W., Momberg, M. and le Roux, P.C., 2025. Improving success rates of remote
conservation translocations by mitigating harsh in-situ environmental
conditions: A case study on a Critically Endangered succulent. Journal for
Nature Conservation.
About the authors:
Arnold Frisby studied Plant Science at Pretoria University followed by a MSc at Northwest University. Since 2016 he has been the curator of the Cycad collection and indigenous Plant Nursery at Pretoria University.
Mia Momberg received a PhD in Plant Science from Pretoria University in 2022, and worked as a Postdoctoral Researcher up to 2024. Since then, she has the role of Senior Scientist for M.A.P. Scientific Services.
Peter le Roux is Professor, Department of Plant and Soil Sciences, University of Pretoria
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