#KNOW

​​Defining the Free State’s Bloemfontein karroid shrubland

Masters student Ricus Nel is growing our knowledge about this unique and biodiverse vegetation through his Master’s research funded by the Botanical Society

DEC 9, 2021 | Written by Zoë Chapman Poulsen, photos supplied by Ricus Nel

Growing our capacity to support, upskill and nurture South Africa’s youth as our next generation of botanists and conservationists is vital to the Botanical Society. BotSoc members and branches are integral in supporting this. And if we can simultaneously address those pressing conservation concerns identified by our branches, then even better.

The Free State Branch has identified Bloemfontein karroid shrubland, also known by its VegMap code Gh8 (part of the Grassland Biome), as a focal point, especially given the threat it faces: that of increasing urbanisation, development and mining around Bloemfontein.

Above: Masters student Ricus Nel in the field in the grasslands of the Free State. Photo supplied by Ricus Nel.

Fortunately Gh8 enthusiast and BotSoc member Ricus Nel has selected this unit as the topic of his Master’s degree at the University of the Free State. This project is supported by the Free State branch of the Botanical Society as a branch conservation project funded by BotSoc National.

There has been considerable debate in the literature around how the Bloemfontein karroid shrubland vegetation should be defined, as well as its current threat status. This forms the main focus of Ricus’s research. This habitat is currently considered Least Concern according to the IUCN (International Union for the Conservation of Nature) Red List, but there is currently insufficient data to quantify if this classification is correct.

Above: Anacampseros filamentosa is one of the dwarf succulent shrubs typical of the Bloemfontein karroid shrubland. Photos by Ricus Nel.

This highly unique and biodiverse vegetation type occurs in an archipelago of isolated patches on dolerite geology within the dry highveld grasslands that are extensive in this region. It is home to a total of 14 endemic plant species.

These dolerite koppies and ridges are characterised by rocky sheets with small pockets of soil. They are home to a variety of dwarf succulent shrubs, bulbs, grasses and ferns with occasional larger shrubs also present.

The grass element of this vegetation is adapted to more arid conditions than the grasses in the surrounding highveld grasslands. In addition, it is highly unusual to find so many karroid vegetation elements such as prominent succulents.

Above: Ricus Nel exploring the Bloemfontein karroid shrubland. Photo supplied by Ricus Nel.

Ricus’s thesis will examine the physical characteristics, vegetation, species richness and distribution of this vegetation unit in comparison to the surrounding vegetation. The main study area is between and surrounding Bloemfontein and the town of Ventersburg. This includes the Free State National Botanical Garden, where karroid shrubland is found in some of the natural areas. In fact, at a Free State branch event on 27 November 2021 Ricus teamed up with CREW BotSoc to build the capacity of Free State’s citizen scientists, introducing participants to some of the vegetation type’s intricacies at the national garden.

One of the main aims of the study is to build a baseline of the species composition and richness of the Bloemfontein karroid shrublands.

Above: The indigenous fern Pellaea calomelanos is commonly seen growing in cracks in the dolerite in Bloemfontein shrubland alongside various xeric grasses. Photo: Ricus Nel.

The research will also start to quantify the land use pressures facing the Bloemfontein karroid shrubland vegetation and will lead to an appropriate threat status designation built on these research findings. Initial observations are that extensive grazing pressure from domestic livestock and the mining of dolerite in the form of borrow pits for road building and maintenance have major impacts. Ricus aims to map these borrow pits to quantify this threat to the vegetation as well as evaluate grazing impacts.

Much of the area of the Free State where Bloemfontein karroid shrubland grows is intensively farmed, particularly in the grasslands that surround this vegetation type. This means that around 10% of Bloemfontein karroid shrubland is already thought to have been transformed for agriculture. However, given the rate of unrecorded illegal ploughing, it is likely that this figure is in fact much higher.

Above: A range of grasses and dwarf succulent shrubs that typify the vegetation growing in cracks of dolerite rock in Bloemfontein karroid shrubland. Photo: Ricus Nel.

Once all this data has been gathered, a map will be produced using Geographical Information Systems (GIS) software defining the extent and boundaries of the vegetation type.This map and dataset will feed into improving future versions of South African National Biodiversity Institute’s National Vegetation Map and the VegMap team and BotSoc’s conservation unit are included in an advisory capacity to ensure alignment with national targets which inform habitat conservation.

Above: The mat-forming succulent Hereroa glenensis produces sweet-scented yellow blooms during the summer months. Here seen in habitat in the Bloemfontein karroid shrubland. Photo: Ricus Nel.

As both Masters student, BotSoc member and biodiversity champion, Ricus hopes to grow our knowledge and raise awareness about this imperilled vegetation through this conservation-focused research which, through working with the Free State branch, will increase understanding of local biodiversity and empower members to act as local conservation agents in their region.

“The beauty of Bloemfontein karroid shrublands is in the diversity of the small things rather than the big things. People have a strong appreciation for these landscapes, but they never sit on their butt in the field, hear the birds, see the skink and look at the small things. Some of these small plants are so cryptic that we may not even see them. They are the most noteworthy and we should be mindful of their conservation. – Ricus Nel