Jan-Hendrik Keet
Jan-Hendrik crawling on all fours to collect seedlings of invasive acacias

Doing whatever it takes to collect data! Jan-Hendrik crawling on all fours to collect seedlings of invasive acacias as part of documenting their invasion dynamics.


I am a botanist/ecologist with a love for nature, but also just science in general. Specifically, I am fascinated by the natural world and the diversity of plants (and animals) that are in it, and there are few things that are more exciting for me than being outdoors and discovering new plants and places.

I completed my BSc Chemistry (2011) and BSc Honours Botany (2012) degrees at the University of the Free State, obtaining both with distinction. I subsequently completed my MSc in Botany (2014) (also at UFS), titled “An assessment of the invasion potential of selected Berberis species (Berberidaceae) in South Africa”, where I surveyed for and documented naturalized populations of Berberis in South Africa and assessed their invasion potential by means of seed germination trails, population dynamics, bioclimatic envelope modelling, and weed risk assessments, and eventually suggested legal and management recommendations on the studied species. Finally, I completed my PhD at Stellenbosch University (2019), titled: “Understanding the biodiversity impacts of invasive legumes: Investigating changes in belowground mutualistic networks, soil conditions, and soil function in response to invasions”. In summary, I investigated the impacts of invasive Australian acacias on fynbos soils in South Africa's Cape Floristic Region by making use of next-generation DNA sequencing techniques, soil enzyme assays, and soil nutrient analysis.

Jan-Hendrik loves to share his botanical knowledge

As part of his “pay-it-forward” life philosophy, Jan-Hendrik loves to share his botanical knowledge with anyone who is keen to listen, to which the high school learners participating in the Iimbovane Outreach Programme will testify.

Current research

There are three research areas that I am focused on: 1) investigating the second invasion “hotspot” of Eucalyptus in south western Limpopo/northern Gauteng (as recorded in the South African Plant Invaders Atlas) in terms of species responsible for invasion (with specific focus on E. camaldulensis), the potential presence of hybrids, and the extent of the invasive populations. 2) Investigating the history of Eucalyptus invasions along selected river systems in the Western Cape. 3) Investigating tree genera that are becoming invasive in and around Stellenbosch, notably Alnus glutinosa (Black Alder) and the genus Fraxinus (Ash), by investigating their invasion history elsewhere in the world, documenting their invasive tendencies in the Stellenbosch area and along riparian zones where they are problematic, and calculating costs of control where data on this is available. The end goal will be to make legal recommendations for listing them in the National Environmental Management: Biodiversity Act.

Jan-Hendrik assists fellow CIB members

Collaboration is key: Jan-Hendrik assists fellow C·I·B members (John Wilson and Nkoliso Magona) to document a forgotten acacia forestry trial near Malmesbury.