SAAB Webinar Recordings – 2022

Webinar 1: Prof. Brian Huntley (SAAB Gold medalist 2022)

Strategic Opportunism for Success in Biodiversity Programmes: Lessons Learned from Pragmatic Approaches in Southern Africa.


Conventional studies and training offered by universities provide very limited preparation for the real world of a professional career in botany and conservation biology. This talk will draw on over fifty years of experience as a botanist, project developer and institutional transformer in several southern African countries, and in ecosystems ranging from the Subantarctic tundra to the Congo rain forests. The period covered spans the years of Portuguese colonial administration of Angola, South Africa’s isolation during the era of grand Apartheid, to the great leap forward of the Mandela years. The emergence and growth of South Africa’s leadership in botany, terrestrial ecology and biodiversity conservation that occurred during challenging and ever-changing socio-political conditions demonstrates the ever-present opportunities available to young biologists, even during difficult times.

Webinar: Prof Brian Huntley
Webinar: Prof Brian Huntley, Question and Answer session

Webinar 2: Prof Ed Witkowski (SAAB Silver medalist 2022)

Studies of threatened plants species in “northern South Africa”


Since 1994, I (we) have undertaken studies, mainly with post-graduate students, on numerous threatened plant species in South Africa. This follows good experiences undertaking such studies on Banksia spp. in Western Australia. It started with a road trip looking at numerous threatened species in the old Transvaal. The endangered (EN) Euphorbia barnardii (1994), Haworthia koelmaniorum (1995/6), and the Critically Endangered (CR) Euphorbia clivicola (1996/7) were the initial studies. A more challenging study started in 1997, which continues to this day, on the CR Protea roupelliae ssp. hamiltonii (“a Protea story”). A theme with some of these studies is previously monitored declines in numbers, but a general lack of, or ineffective, action to stem the declines. The way fire is managed has also been shown to be critical for many of them. These studies were followed by Kniphofia umbrina (CR) in Swaziland (Eswatini), Ceropegia decidua subsp. pretoriensis (CR), Adenium swazicum (CR), six Delosperma spp. (mesems, two EN, 4 CR). Aloe spp., particularly A. peglerae (focus on pollination), and Kumara (Aloe) plicatilis (Western Cape), became a new focus beyond 2000, with a particular interest in pollination.  These were followed by KZN and Eastern Cape succulent Euphorbia species, E. umfoloziensis (Extinct in the wild?), and E. bupleurifolia, a “common species” becoming uncommon at a rapid rate.  Illegal harvesting of small succulent plants from the wild and trade have been problematic for many years. Indigenous medicinal plant species have also been a focus throughout. Finally, studies on protected tree species, such as marula, baobab and the pepperbark tree have been undertaken and continue. 

SAAB Webinar: Prof Ed Witkowski

Webinar 3: Dr Daniel Zhigila (SAAB Bronze Medalist 2022)

Systematics and extinction risk patterns in Thesium (Santalaceae)


Recent phylogenetic studies circumscribed the genus Thesium as monophyletic by including four segregate genera: Austroamericium, Chrysothesium, Kunkeliella and Thesidium. Additionally, the Greater Cape Floristic Region (GCFR) Thesium, having both ecological specialists and generalists, typifies an appropriate system for evaluating both the correlates of range extent and specialization, and the relative extinction risks associated with both. For my PhD, we tested the monophyly of the genus Thesium and its infrageneric taxa using expanded taxon sampling and phylogenetic analyses. One of the key objectives is to develop a well-resolved phylogeny that will allow a piece-wise revision of complex clades. Further, we tested the hypothesis that range size, ecological specialization and extinction risks are phylogenetically structured and then asked whether these will impact Thesium phylogenetic diversity. For the later, we quantified and modelled the niche breadth for each species based on the contemporary geographic range extents and ecological specializations. Key novelties include: i) establishment of an infrageneric classification scheme based on an integrative approach for the genus. This classification recognized five monophyletic subgenera, reflecting evolutionary relatedness and each supported by unambiguous morphological characters; ii) a detailed taxonomic revision for the T. subgenus Hagnothesium, comprising eight species which are all endemic to the Cape Region; iii)  discovery and description of eight species new to science, the majority of which are restricted to the highly fragmented agricultural landscape in the Agulhas Plain; iv) our data suggest a strong positive correlation between environmental variables and species range extents. However, the range extent, ecological specializations and extinction risk are phylogenetically random; and iv) the conservation status of the Cape Thesium was provided to aid in developing conservation strategies in the face of accelerated climate change.

Webinar 4: Dr Pedro Bergamo

‘Pollination ecology without pollinators: patterns and processes in low pollination environments’


Pollination is often disregarded as a process that determines vegetation patterns and processes. However, pollination can be an important niche axis in plant communities, shaping plant community structure and dynamics. Such roles of pollination niches should be more important in low pollination environments where pollinators are a scarce resource for plants. In this talk, I will present results showing the role of pollination in shaping plant-plant interactions from a low pollination environment, the Brazilian highland grasslands. In sum, pollination niches were important in maintaining plant diversity by conferring advantages to rare plants while disadvantages to abundant ones. Nevertheless, such patterns depended on the pollinator group (i.e. bees, flies or hummingbirds) and on the pollination success component (i.e. pollen receipt onto stigmas vs. pollen removal from anthers). Based on these results, we support pollination as an important niche axis in plant communities that should be accounted for when investigating vegetation patterns and processes.

Webinar 4: Prof. Jill Farrant

Desiccation tolerance:  A solution to food security and continued human well-being in hotter drier future?

JM Farrant1 and HWM Hilhorst2.

1DSI-NRF SARChI, Systems Biology Studies in Plant Desiccation Tolerance for Food Security.

2Honorary Research Associate, University of Cape Town.

Department of Molecular and Cell Biology, University of Cape Town, South Africa.

Desiccation tolerance, the ability to survive loss of 90 -95% cellular water for prolonged periods of time, is an ancient and almost ubiquitous trait within land plants.  It appeared very early in the evolution of terrestrial life, being common in cyanobacteria, lichens and green algae and is believed to be present in the ancestor to all land plants.  Vegetative desiccation tolerance was lost as land plants evolved vascular systems and alternative strategies of water management but was retained in reproductive structures (spores and seeds) of most species.  However, vegetative desiccation tolerance has reappeared in at least 13 angiosperm lineages, but in total in only 240 species, termed ‘resurrection plants’.  This rare phenotype evolved in species occupying rocky, seasonally dry niches, with the majority of known angiosperms occurring in Africa. 

Modern agriculture is almost entirely based on the system of vegetative desiccation sensitivity, and seed desiccation tolerance.  The latter is also used for germplasm conservation of angiosperm species.  Forged during the green revolution, in an era of adequate water supply, breeding for increased seed size and yield has resulted in loss of inherent resilience to water deficit stress in all crops forming the basis of world food security. Now in the era of climate change, where increased aridification is predicted in most current food producing areas, including the bulk of Africa, these breeding strategies are failing. Furthermore, the seeds of at least a 100 of our economically important crops, including coffee, cacao and citrus, are desiccation sensitive, or ‘recalcitrant’, with as yet no known mechanisms for storage beyond a few months at most. Due to ongoing droughts, much of the coffee production in Brazil and Ethiopia are under threat. In this talk, we propose that understanding desiccation tolerance could lead to solutions for improved food security, health and for paving the way to life on other planets.  It will be based on aspects of my life long multidisciplinary research on recalcitrant seeds and resurrection plants.