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SA now experiencing half-year summers

12 October 2020 | Story Leonie Bolleurs | Photo Supplied

Although several international studies have used temperature metrics to statistically classify their seasonal divisions, a study in which Adriaan van der Walt was involved, would be the first known publication in a South African context using temperature as classification metric.

Gone are the days when we as South Africans would experience a three-month spring season, easing into summer, and then cooling off for three months before we hit winter.

Adriaan van der Walt, Lecturer in the Department of Geography at the University of the Free State (UFS), focuses his research on biometeorology (a specialist discipline exploring the role and climate change in physical and human environments) as well as climatology and geographic information systems.

He recently published an article: ‘Statistical classification of South African seasonal divisions on the basis of daily temperature data’ in the South African Journal of Science.

In this study, which Van der Walt undertook with Jennifer Fitchett, a colleague from the University of the Witwatersrand, data on daily maximum and minimum temperatures was collected from 35 meteorological stations of the South African Weather Service, covering the period between 1980 and 2015.

They went to great lengths to ensure that they had a complete set of data before presenting it to demonstrate seasonal brackets.

First for South Africa

Their statistical seasonal brackets indicate that South Africans now experience longer summers (from October to March), autumn in April and May, winter from June to August, and spring in September.

Although considerable work has been done using rainfall to determine seasonality in Southern Africa, Van der Walt believes that these methods did not work well as there are too many inconsistencies in this approach, as identified by Roffe et al. (2019, South African Geographical Journal). To make matters more complicated – as a semi-arid region, and with desert conditions along the west coast – some regions do not have enough rainfall to use as a classifier.

Temperature, on the other hand, worked well in this study. “Temperature, by contrast, is a continuous variable, and in Southern Africa has sufficient seasonal variation to allow for successful classification,” says Van der Walt.

He continues: “Although several international studies used temperature metrics to statistically classify their seasonal divisions, this study would be the first known publication in a South African context using temperature as classification metric.”

Van der Walt says what we understand as seasons largely relates to phenology – the appearance of blossoms in spring, the colouration and fall of leaves in autumn, and the migration of birds as a few examples. “These phenological shifts are more sensitive to temperature than other climatic variables.”

Seasonal brackets

According to Van der Walt, they believe that a clearly defined and communicated method should be used in defining seasons, rather than just assigning months to seasons.

“One of the most important arguments of our work is that one needs to critically consider breaks in seasons, rather than arbitrarily placing months into seasons, and so we welcome any alternate approaches,” he says.

A number of sectors apply the temperature-based division to their benefit. “For example, in the tourism sector it is becoming increasingly important to align advertising with the season most climatically suitable for tourism,” says Van der Walt.

Temperature-based division is also used to develop adaptive strategies to monitor seasonal changes in temperature under climate change. However, Van der Walt points out that each sector will have its own way of defining seasons. “Seasonal boundaries should nevertheless be clearly communicated with the logic behind them,” he says.

News Archive

Dr Francois Deacon appears in international film, Last of the Longnecks, due to research on giraffes

2017-04-04

Dr Francois Deacon was invited by the producer of Last
of the Longnecks to be part of a panel handling a question-
and-answer-session about the film.
Photo: Supplied

A great honour was bestowed on a researcher at the University of the Free State (UFS) when he was invited to the preview of the documentary film, Last of the Longnecks. Dr Francois Deacon, lecturer and researcher in the Department of Animal, Wildlife and Grassland Sciences at the UFS, who also has a role in the film, attended the preview at the Carnegie Institution for Science’s Smithsonian National Museum in Washington DC, in the US, in March this year. The preview formed part of the DC Environmental Film Festival.

The Environmental Film Festival in the US capital is the world’s leading showcase of films with an environmental theme and which aims to improve the public’s understanding of the environment through the power of film. During the festival, the largest such festival in the US, more than 150 films were shown to an audience of 30 000 plus.

Dr Deacon was invited by the producer of Last of the Longnecks to be part of a panel handling a question-and-answer-session about the film directly after the show. He described it as the greatest moment of his life.

Role in the film Last of the Longnecks

“My role in the film was as the researcher studying giraffes in their natural habitat in order to understand them better, so that we may better protect them, and be able to provide better education on the problem in Africa,” says Dr Deacon.

“Together with Prof Nico Smit, also from the UFS Department of Animal, Wildlife and Grassland Sciences, Hennie Butler from the Department of Zoology, and Martin Haupt from Africa Wildlife Tracking, we were the first researchers in the world to equip giraffes with GPS collars and to conduct research on this initiative,” he says. This ground-breaking research has attracted international media attention to Dr Deacon and Prof Smit.

“Satellite tracking is proving to be extremely valuable in the wildlife environment. The unit is based on a mobile global two-way communication platform, utilising two-way data satellite communication, complete with GPS systems.

“It allows us to track animals day and night, while we monitor their movements remotely from a computer over a period of a few years. These systems make the efficient control and monitoring of wildlife in all weather conditions and in near-to-real time possible. We can even communicate with the animals, calling up their positions or changing the tracking schedules,” says Dr Deacon.

The collars, which have been designed to follow giraffes, enable researchers to obtain and apply highly accurate data in order to conduct research. Data can be analysed to determine territory, distribution or habitat preference for any particular species.

Over a period of three years (2014-2016), the Last of the Longnecks team from Iniosante LLC captured on film how Dr Deacon and his team used the GPS collars in Africa to collect data and conduct research on the animals.

“With our research, which aims to understand why giraffes are becoming extinct in Africa, we are looking at the animal in its habitat but not only the animal on its own. If the habitat of these animals is lost, they will be lost as well. Therefore, our focus is on conservation and better understanding the habitat. The giraffe is only a tool to better understand the habitat problem,” says Dr Deacon.

Since the beginning of his research Dr Deacon and his team have had six new collar designs, with animals in four different reserves being equipped with the collars. The collars use the best technology available in the world and make it possible to determine how giraffes communicate over long distances, and how their sleep patterns function. Physiological and biological focus is placed on the giraffe’s stress levels, natural hormone cycles, and milk quality in cows.

Photo: Supplied

Experience at the film festival

“Absolutely amazing. Totally beyond our frame of reference as South Africans.” This is how Dr Deacon describes his experience of the three days in Washington DC during the film festival.

“It was an absolute honour to be part of the global preview of the film and to be able to work with Ashley Davison, the director of the film, and his team. I am just a rural farm boy who dreams big, and now this dream is known worldwide!” he says.

The film, which will be launched in April, will be screened in South Africa on the National Geographic channel in May 2017. Meanwhile, the film will also be shown at eight other film festivals in the US.

Work will start on a follow-up documentary in October and Dr Deacon is excited about the prospect. A mobile X-ray machine will be available from October. Internal sonars could also be performed on each of the animals. Researchers from around the world will form part of the team which will be led and co-ordinated by Dr Deacon and his co-workers at the UFS.

Former articles:

18 Nov 2016: http://www.ufs.ac.za/templates/news-archive-item?news=7964
23 August 2016: http://www.ufs.ac.za/templates/news-archive-item?news=7856
9 March 2016:Giraffe research broadcast on National Geographic channel
18 Sept 2015 Researchers reach out across continents in giraffe research
29 May 2015: Researchers international leaders in satellite tracking in the wildlife environment

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