Latest News Archive

Please select Category, Year, and then Month to display items
Previous Archive
01 July 2020 | Story Thabo Kessah | Photo Supplied
Breathtaking views of the misty Bvumba mountains.

While the Afromontane Research Unit (ARU) will always have a core focus on the sustainable development of the Maloti-Drakensberg (Lesotho-South Africa), the Southern African region is also very important to the unit. The primary reason for this is that Southern African mountains – the most important water-production landscapes in our drought-prone region – have no collective voice for their sustainable management. As such, there is no regional science-policy-action pipeline to secure these mountains for interventions to ensure that they can still produce key ecosystem services under global change. This is in contrast to East Africa where there is a much better-established community of practice for the charismatic African giants such as Mount Kilimanjaro. 

ARU-Southern African collaboration
To this end, the Director of the ARU, Dr Ralph Clark, revealed that the ARU has close links with academics, practitioners, and lay experts in Zimbabwe for the careful documenting of mountain biodiversity in the Manica Highlands. This is a trans-national mountain system critical for water supply to both Zimbabwe and Mozambique. The Bvumba (‘mist’ in Shona) Mountains are situated in the centre of the Manica Highlands. The name Bvumba is derived from the regular mist covering these mountains.

“The Bvumba has a complex socio-political history extending far back, before the arrival of the Portuguese in the 1400s. Despite this history of human occupation, and despite a century of botanical exploration in the 20th century, a comprehensive list of plant species – including endemic species – has never been published for the Bvumba. Such basic lists are essential for foundational knowledge that can drive sustainable development and responsible management of natural resources,” Dr Clark said.

The ARU and partners have collaborated to compile records of the first comprehensive species list for the Bvumba. “This project was done in partnership with the Harare Herbarium, Belgium’s Meise Botanical Gardens, the Flora of Zimbabwe and Mozambique projects, the Biodiversity Foundation for Africa, and the UK’s Royal Botanical Gardens, Kew. It was recently completed with a publication in the journal PhytoKeys.”

Bvumba’s hundreds of species
The Bvumba has a plant species complement of 1 127 native taxa in an area of only 276 square kilometres. “There is remarkable fern and orchid diversity in these mountains, with 137 fern species that is considered to be the richest fern locality in Southern Africa.  There are also 125 orchid species that make it exceptionally rich for this group. The only local Bvumba endemic is a critically endangered epiphytic forest orchid. Six other near-endemic plant taxa occur in the Bvumba, all of which are endemic to the Manica Highlands from Nyanga to Chimanimani,” added Dr Clark.

Low levels of local endemism are likely to be an effect of the Bvumba having limited natural grassland compared to forest. “Second to fynbos, grassland is the most endemic-rich habitat in Southern African mountains. Montane forests are poor in local endemics by comparison, which is contrary to what many would suppose. As in mountains across Southern Africa, invasive species are a major risk to water security, biodiversity conservation and livelihoods. The Bvumba is no exception, with Australian blackwood (Acacia melanoxylon), ginger lily (Hedychium gardnerianum), and bee bush (Vernonanthura polyanthes) being the most problematic species of the 123 naturalised introductions. While the Zimbabwean side of the Bvumba is the best explored, the Mozambican side of Serra Vumba offers exciting opportunities for further botanical research,” he emphasised.

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.

 

We use cookies to make interactions with our websites and services easy and meaningful. To better understand how they are used, read more about the UFS cookie policy. By continuing to use this site you are giving us your consent to do this.

Accept