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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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News Archive

Sunflowers are satellite dishes for sunshine, or are they?
2016-07-20

Eighty-six percent of South Africa’s
sunflowers are produced in the
Free State and North West provinces.

Helen Mirren, the English actress, said “the sunflower is like a satellite dish for sunshine”. However, researchers at the University of the Free State (UFS) have found that too much of this sunshine could have a negative effect on the growth of sunflowers, which are a major source of oil in South Africa.

According to Dr Gert Ceronio from the Department of Soil, Crop, and Climate Sciences at the UFS, extremely high soil temperatures play a definite role in the sprouting of sunflower seedlings. Together with Lize Henning, professional officer in the department, and Dr André Nel from the Agricultural Research Council, he is doing research on biotic and abiotic factors that could have an impact on sunflowers.

Description: Sonneblom 2 Tags: Sonneblom 2

Various degrees of deformity (bad-left
to none-right) in seedlings of the same
cultivar at very high soil temperatures.
Photo: Dr Gert Ceronio

Impact of high temperatures on sunflower production

The Free State and North West provinces, which produce 86% of South Africa’s sunflowers, are afflicted especially by high summer temperatures that lead to extremely high soil temperatures.

Dr Ceronio says: “Although sunflower seeds are able to germinate at temperatures from as low as 4°C to as high as 41°C, soil temperatures of 35°C and higher could have a negative effect on the vegetative faculty of sunflower seedlings, and could have an adverse effect on the percentage of sunflowers that germinate. From the end of November until mid-January, this is a common phenomenon in the sandy soil of the Free State and North West provinces. Soil temperatures can easily exceed the critical temperature of 43°C, which can lead to poor germination and even the replanting of sunflowers.”

Since temperature have a huge impact not only on the germination of sunflower seeds, but also on the vegetative faculty and sprouting of sunflower seedlings, Dr Ceronio suggests that sunflowers should be planted in soil with soil temperatures of 22 to 30°C. Planting is usually done in October and early November. Unfortunately, this is not always possible, as soil moisture is not optimal for growth. Farmers are then compelled to plant sunflowers later.

Impact of herbicides on sunflower growth

“High soil temperatures, combined with the herbicide sensitivity of some cultivars, could lead to the poor development of seedlings," says Dr Ceronio.

The use of herbicides, such as ALACHLOR, for the control of weeds in sunflowers is common practice in sunflower production. It has already been determined that ALACHLOR could still have a damaging effect on the seedlings of some cultivars during germination and sprouting, even at recommended application dosages.

“The purpose of the continued research is to establish the sensitivity of sunflower cultivars to ALACHLOR when exposed to high soil temperatures,” says Dr Ceronio.

 

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