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- ItemThe botanist from Belvidere: the living legacy of Augusta Vera Duthie (1881-1963)(Elsevier B.V., 2025-04-25) Fourie-Basson, Wiida; Hills, Paul; Dreyer, Leanne L.Here we review the life, career, botanical contribution and legacy of the founder of the Botany department at Stellenbosch University, Augusta Vera Duthie. We briefly introduce her, outline her background and personal life, as best as could be reconstructed from the few available publications and documents on her life. We then shift our focus to her long, often uphill, yet most impressive establishment and development of the Botany department at Victoria College (which later became Stellenbosch University). All attempts were made to highlight innovative initiatives she embarked upon to secure funding to grow the department, to the extent that she eventually managed to found the Stellenbosch University Herbarium and its associated library, the Stellenbosch University Botanical Gardens, and ultimately a fully functional Botany department, complete with lecturing facilities and laboratories. Reconstructing this chapter of her life relied heavily on a treasure trove of documents and letters held in the Stellenbosch University Library's Special Collections. The paper next briefly reviews her botanical contribution, focussing particularly on her work on the lowland flora of Stellenbosch. Again, documents, letters and photographs held in the Special Collection and Stellenbosch University Archives help illuminate her contributions as a botanist. We conclude by reviewing the different components of her rich legacy, and how most of these initiatives are being maintained to this day. Here we place a fairly strong emphasis on the Duthie reserve, and the ongoing conservation efforts to conserve this precious fragment of veld, the last remaining home to the critically endangered Haemanthus pumilio.
- ItemDisentangling the relationships among abundance, invasiveness and invasibility in trait space(Springer Nature, 2023-06-09) Hui, Cang; Pysek, Petr; Richardson, David M.Identifying conditions and traits that allow an introduced species to grow and spread, from being initially rare to becoming abundant (defined as invasiveness), is the crux of invasion ecology. Invasiveness and abundance are related but not the same, and we need to differentiate these concepts. Predicting both species abundance and invasiveness and their relationship in an invaded community is highly contextual, being contingent on the community trait profile and its invasibility. We operationalised a three-pronged invasion framework that considers traits, environmental context, and propagule pressure. Specifically, we measure the invasiveness of an alien species by combining three components (performance reflecting environmental suitability, product of species richness and the covariance between interaction strength and species abundance, and community-level interaction pressure); the expected population growth rate of alien species simply reflects the total effect of propagule pressure and the product of their population size and invasiveness. The invasibility of a community reflects the size of opportunity niches (the integral of positive invasiveness in the trait space) under the given abiotic conditions of the environment. Both species abundance and the surface of invasiveness over the trait space can be dynamic and variable. Whether an introduced species with functional traits similar to those of an abundant species in the community exhibits high or low invasiveness depends largely on the kernel functions of performance and interaction strength with respect to traits and environmental conditions. Knowledge of the covariance between interaction strength and species abundance and these kernel functions, thus, holds the key to accurate prediction of invasion dynamics.