Webinar 4: Prof Anton Pauw (SAAB Silver Medal Winner 2023)
Pollinators and plant conservation in the Cape.
Prof. Anton Pauw
Department of Botany and Zoology Stellenbosch University
In this talk, I want to explore three questions about plant species: How do they originate, how do they coexist in communities, and how do we conserve them? I am lucky to live in the Cape region of South Africa, where the very large number of plant species allow us to evaluate our answers to these questions. I have chosen to look for answers by studying plant-pollinator interactions because, on the one hand, pollinators determine which plants mate with each other, and that must surely be important in speciation, and on the other hand, because pollination is usually needed for seed production and seeds are often required for plant population persistence. I will end the talk by discussing how the growing understanding of pollination can be applied in hands-on conservation actions.
Webinar 3: Prof VR Clark (on behalf of Prof Moffett – SAAB Silver Medal Winner 2023)
The Limpopo–Mpumalanga–Eswatini Escarpment—Extra-Ordinary Endemic Plant Richness and Extinction Risk in a Summer Rainfall Montane Region of Southern Africa
Prof. V Ralph Clark
Director: Afromontane Research Unit & Dept of Geography
University of the Free State: QwaQwa Campus
Presented on behalf of all collaborators: Mr John Burrows, Ms Barbara Turpin, Prof. Kevin Balkwill, Dr Mervyn Lötter and Prof. Stefan Siebert
Climatic, edaphic, and topographic differences between mountains and surrounding lowlands result in mountains acting as terrestrial islands with high levels of endemic biota. Conservation of mountains is thus key to successful biodiversity conservation. The Limpopo–Mpumalanga–Eswatini Escarpment (LMEE) in South Africa and the Kingdom of Eswatini is one of the largest components of southern Africa’s Great Escarpment. Despite botanical collecting effort over 150 years, there has never been a holistic and comprehensive synthesis of plant endemics data for the LMEE. For the first time, we define the LMEE as an orographic entity, covering 53,594 km2; it forms a contiguous highland area from the Pongola River in the south, north to the Woodbush area, and includes rugged western Eswatini. Using exhaustive literature mining, coupled with combined decades of fieldwork by the authors, and up-to-date taxonomic assessments of the 46 undescribed species, we provide the first robust list of plant endemics for the LMEE. The LMEE has 496 endemic plant taxa, comprising 10.7% of the provisional flora (4,657 taxa). This is more than double the endemic plant taxa in the Drakensberg Mountain Centre (DCM), and may be the richest concentration of montane endemics in southern Africa outside of the Core Greater Cape Floristic Region. Grassland hosts the largest number of endemics (74.2%), followed by Savanna (26.6%), then Forest (7.7%). Most endemics of conservation concern occur in Grassland (68.4%), in which one is Extinct and two are Extinct in the Wild. Evolutionary partitioning between Grassland, Savanna and Forest is suggested by low introgression of Biomes at family and genus level, and by a dominance of life-forms adapted to open habitats. High threat statuses for Grassland endemics can be attributed to the historical transformation of almost 20% of Grassland to forestry pre-1990, and ongoing degradation of primary Grassland. With conservation area coverage only 11.1% of the LMEE, the exceptional richness of the endemic flora -combined with major conservation threats—suggest that the LMEE should become a major focus of conservation effort between South Africa and Eswatini as a matter of urgency.
Webinar 2: Prof Steve Johnson (SAAB Gold Medal Winner 2023)
The role of volatiles in mediating plant-animal interactions
Plant signalling to animals often involves volatiles that are difficult for humans to detect. Since 2007 the pollination research group at UKZN has been using chemical ecology methods such as GC-MS, GC-EAD and field bioassays to better understand the functional basis of plant-pollinator interactions. In recent years this approach has been extended to include plant-seed disperser interactions. We are still on a steep learning curve, but the incorporation of chemical ecology has enriched our research capacity and has also led to many interesting new avenues of research. This talk will highlight some of the progress we have made and outline some of our plans for the future. I will summarize some of our findings on the chemical ecology of pollination systems involving rodents, beetles, flies, wasps and hawkmoths. This will include studies of how plants use false advertising in mimicry systems. I will also discuss a few key findings of our research on plant deployment of fruit volatiles as signals that lead to seed dispersal.
Webinar 1: Dr Mia Momberg (SAAB Bronze Medal Winner 2023)
‘Where does wind matter?’
How biological communities respond to changes in climate has been studied extensively, but with a large bias to focusing on temperature and precipitation as climatic factors. The roles of other climatic factors are, however, comparatively poorly understood, despite potentially also strongly structuring community patterns. For example, wind may have direct physiological and mechanical impacts on plants, soil, and animals, yet is seldom considered in forecasts of species responses to future change. It is, therefore, important to understand the magnitude of the potential impacts of changing wind conditions on biological communities. Wind speeds have accelerated globally over the past decade, making this topic increasingly relevant. The largest global changes to wind speed to date have occurred in the Southern Ocean. Marion Island is used a study system which experiences wind on most days of the year, and the response of taxa across multiple spatial scales is investigated. At the broadest scale, across the whole island, wind velocity was an important predictor in driving the occurrence of vegetation types on the island, as well as to a lesser degree determining the total vegetation cover. At a finer spatial scale, using data from 1 m2 quadrats, wind stress significantly affected plant species richness, vegetation cover, and community composition, even after accounting for other ecophysiologically-important predictors. Species richness showed a hump-shaped relationship with wind stress, where the most species were found under intermediate wind stress conditions, while locations with the highest wind stress contained the highest percentage of vegetation cover. Individual species showed differing responses to wind conditions, leading to turnover along the wind stress gradient that resulted in differences in community composition. Wind stress had a significant effect on the occurrence of 75% of the species, and was a more important predictor than any temperature- or moisture-related variables for half of the species that were significantly affected. Wind conditions are, therefore, strongly related to multiple aspects of biological communities in this ecosystem that experiences chronic winds. Consequently, it is clear that wind should be considered as a climatic driver of ecological patterns, and be included in future climate forecasts.
Webinar: Wiley Digital Archives
A virtual tour of the Environmental Science and History archives and other Wiley Digital Archives.
Please follow the link to the recording of this webinar: