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26 July 2021 | Story Nonsindiso Qwabe | Photo Nonsindiso Qwabe
On top of the Drakensberg. The ARU and Witsieshoek Mountain Lodge research team are, from the left: Grant Martin, Dr Ralph Clark, Jan van Niekerk, Prof Aliza le Roux, Prof Peter Taylor, and Dr Sandy Steenhuisen.

All mountains around the world have native and non-native species that are expanding their ranges quite dramatically; however, little research has been conducted towards understanding the long-term redistribution of species and the effects of global change on biodiversity.


The Afromontane Research Unit (ARU) on the University of the Free State Qwaqwa Campus – as part of the Mountain Invasion Research Network – has secured a two-year EU Horizon 2020 project under the Department of Science and Innovation, which will be looking at the mechanisms underlying the success and impact of range-expanding species on biodiversity and ecosystem functioning.

On Monday 19 July 2021, the ARU took a few of its researchers on a scenic helicopter ride to the summit of the Drakensberg for an alpine field-experiment site inspection of the Mont-aux-Sources peak, one of the highest sections of the Drakensberg range. This site has been identified for the project which the research unit will be leading on mountain research.

ARU Director, Dr Ralph Clark, said the project would explore the effects of global change, biological invasions (when species invade new geographic regions), as well as climate and land-use change. He said experiments were needed to explore the various possibilities and to test the extent to which species respond to experimental treatments. The project would therefore be conducting experiments for two years using open-top chambers – causing an increase in temperature of 3 or 4 degrees to what you find naturally – on plant species from lower down to the top of the mountain, to see how they function. “This will give us an idea of whether they will be able to survive in global warming scenarios. If temperatures get warmer, we might start seeing a lot of plants up here that we wouldn’t otherwise find here.”

Dr Clark said little is known about the long-term monitoring of species distribution and the effects of global change. Implementing the project in the Maloti-Drakensberg alpine area will therefore put the area in the global mountain research arena. The elevational gradient in the Maloti-Drakensberg Mountains provides space to explore the key processes underlying the variation in species elevation with climate change. “One of the things we don’t know much about are alpine systems. We are hoping to establish a long-term alpine research site and try to add as many studies as we can. The more science we can bring up here, the more we can know about mountain life. What happens on mountains has a lot of impact on social dynamics.

“This project is looking to see what is driving range expansion. Every mountain has its own context. In the Swiss alpine, fires are not a big factor, but fires are one of the biggest factors on our mountains. Some of our native and non-native species are therefore fire-driven, so as fire increases, you might have them spreading faster.”

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Water erosion research help determine future of dams
2017-03-07

Description: Dr Jay le Roux Tags: Dr Jay le Roux

Dr Jay le Roux, one of 31 new NRF-rated
researchers at the University of the Free State,
aims for a higher rating from the NRF.
Photo: Rulanzen Martin

“This rating will motivate me to do more research, to improve outcomes, and to aim for a higher C-rating.” This was the response of Dr Jay le Roux, who was recently graded as an Y2-rated researcher by the National Research Foundation (NRF).

Dr Le Roux, senior lecturer in the Department of Geography at the University of the Free State (UFS), is one of 31 new NRF-rated researchers at the UFS. “This grading will make it possible to focus on more specific research during field research and to come in contact with other experts. Researchers are graded on their potential or contribution in their respective fields,” he said.

Research assess different techniques
His research on water erosion risk in South Africa (SA) is a methodological framework with three hierarchal levels presented. It was done in collaboration with the University of Pretoria (UP), Water Research Commission, Department of Agriculture, Forestry and Fisheries, and recently Rhodes University and the Department of Environmental Affairs. Dr Le Roux was registered for 5 years at UP, while working full-time for the Agricultural Research Council – Institute for Soil, Climate and Water (ARC-ISCW).

Water erosion risk assessment in South Africa: towards a methodological framework
, illustrates the most feasible erosion assessment techniques and input datasets that can be used to map water erosion features in SA. It also emphasises the simplicity required for application at a regional scale, with proper incorporation of the most important erosion-causal factors.

The main feature that distinguishes this approach from previous studies is the fact that this study interprets erosion features as individual sediment sources. Modelling the sediment yield contribution from gully erosion (also known as dongas) with emphasis on connectivity and sediment transport, can be considered as an important step towards the assessment of sediment produce at regional scale. 
 
Dams a pivotal element in river networks

Soil is an important, but limited natural resource in SA. Soil erosion not only involves loss of fertile topsoil and reduction of soil productivity, but is also coupled with serious off-site impacts related to increased mobilisation of sediment and delivery to rivers.

The siltation of dams is a big problem in SA, especially dams that are located in eroded catchment areas. Dr Le Roux recently developed a model to assess sediment yield contribution from gully erosion at a large catchment scale. “The Mzimvubu River Catchment is the only large river network in SA on record without a dam.” The flow and sediment yield in the catchment made it possible to estimate dam life expectancies on between 43 and 55 years for future dams in the area.
 
Future model to assess soil erosion
“I plan to finalise a soil erosion model that will determine the sediment yield of gully erosion on a bigger scale.” It will be useful to determine the lifespan of dams where gully erosion is a big problem. Two of his PhD students are currently working on project proposals to assess soil erosion with the help of remote sensing techniques.

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