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12 October 2020 | Story Leonie Bolleurs | Photo Supplied
Adriaan van der Walt
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

Predation Management Centre helps stock farmers to address predator problem
2017-03-29

Description: Predation Management Centre  Tags: Predation Management Centre

Predators, including caracal and foxes, are costing the
livestock industry about R2 billion annually. The
Predation Management Information Centre was
established to collect, analyse, and make information
available on predation and predation management to
stock and game farmers.
Photo: Pixabay

Predators are costing the livestock industry about R2 billion annually. To address the problem, the Department of Animal, Wildlife and Grassland Sciences at the University of the Free State (UFS) teamed up with the Predation Management Forum (PMF).

Predation Management Information Centre established
The UFS has signed service agreements for the establishment of a Predation Management Information Centre with the four industries (wool, mohair, red meat, and game industries) forming part of the PMF. The centre will collect and analyse information on predation and predation management. This information will then be made available in a management information system and information contained in the system will be made available to all users.

Centre makes essential information available
At the information centre, a team of dedicated staff members handles calls and enquiries. Experts in the team are also available to provide advice to farmers. Furthermore, the centre is responsible for the management of information and resources. Relevant policy documents and scientific articles will be stored in an archive at the centre which will also collect research, statistics, biometric information, and information on new research topics.

The information that is collected will be used to assist farmers with predation management. Information on methods which are effective in a specific situation will be made available to farmers in order to help reduce predation on their farms. “By focusing on non-lethal methods in predation management, best practices can be compiled in order to restrict losses attributed to predation to the minimum,” says Quinette Kruger from the information centre.

Contact details for authorities and specialists managing damage-causing animals will also be provided by the centre.

The information centre invites stock farmers, game farmers, the general public, retail, authorities, and other stakeholders to contact the centre at +27 51 401 2210 or PredationMC@ufs.ac.za.

Read more about the ALPRU project.


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