SAAB Webinar Programme 2021

In lieu of our annual conference in 2021, we will be holding a series of webinars. The first of these will be in January – our Silver and Bronze medal awardees have kindly agreed to be our first speakers. Please join us to recognise and celebrate their fantastic achievements.

Wednesday 20 January:  Bronze Medal Winner: To be announced on the day – will present some of his PhD work on invasion biology

Wednesday 27 January: Silver Medal Winner: Prof. Timm Hoffman

Rethinking catastrophe? Historical trajectories and modelled future vegetation change in southern Africa

(Details on next page)

Time: 16h00 pm

How: A Zoom webinar invitation will be sent out in early January. Please accept to register.

How long? Presentations will be ca. 45 minutes long with 15 – 20 minutes for questions.

Please share this invitation with members of your Institution/community who may be interested.


Rethinking catastrophe? Historical trajectories and modelled future vegetation change in southern Africa


Most projections of climate change for southern Africa describe a hotter and drier future with catastrophic consequences for the environment and socio-ecological sustainability of the region. This study investigated whether evidence of the projections for the climate and vegetation of the subcontinent is already evident. Analysis of the climate record indicate that the historical trend of increasing temperature is consistent with future projections for the region. Rainfall, however, apparently has not changed significantly. Results from an analysis of 1321 repeat historical photographs indicate broad trends in vegetation trajectories in the major biomes of southern Africa. The Savanna biome has experienced a rapid increase in woody plant at rates un-anticipated by the models. Contrary to early projections for the Succulent Karoo biome, biomass and cover have increased, largely in response to changes in land-use practices. Cover in the fire-adapted Fynbos biome has remained stable or increased over time with unanticipated expansion of forest species, particularly in localities protected from fire for long periods. The shrub-dominated Nama-karoo Biome has seen an increase in grass cover. Rather than contracting, as suggested in the early models, the Grassland biome has apparently expanded westwards into former Nama-karoo biome sites. The broad trends in historical trajectories illustrate how land-use management has influenced vegetation change in the past. They also provide a useful context for evaluating future changes and developing mitigation strategies for some of the worst impacts of climate change in the future.

About the Speaker: Prof. Timm Hoffman

Timm Hoffman holds the Leslie Hill Chair in Plant Conservation in the Department of Biological Sciences at the University of Cape Town. After completing his PhD at UCT in 1989 he spent a post-doc at the Jornada Long Term Ecological Research program in New Mexico, USA before joining the South African National Biodiversity Institute in 1991. He led a national review of land degradation in South Africa which was published as a co-authored book in 2000. He has been at UCT since 2001 where he is the Director of the Plant Conservation Unit. Timm is interested in how southern African environments have changed over time primarily in response to land use and climate. He has a special interest in the arid parts of southern Africa and uses repeat photography to understand the nature, extent and rate of long-term vegetation change in the region. He takes an interdisciplinary approach to the study of environmental change and includes elements from the historical, anthropological and social sciences in his research. In recognition of the interdisciplinary nature of his contributions, especially in the communal areas of Namaqualand, Timm was the recipient of the WWF Living Planet Award in 2020. He also received the SAAB 2021 Silver Medal Award for his research and other contributions to the advancement of botany in South Africa. Further details about his research and teaching interests can be found at:

Note: This presentation is based on a paper published in Anthropocene in 2019 by authors: M Timm Hoffman, Rick Rohde and Lindsey Gillson.

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