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Curiosity about environmental changes drives Dr Katlego Mashiane’s PhD research

21 April 2023 | Story Leonie Bolleurs | Photo Supplied

Striving to make a difference in the field of biodiversity conservation, Dr Katlego Mashiane decided to pursue a PhD in Geography, focusing on the spatial modelling of grassland diversity and nutrients in subalpine environments. He received his PhD during the recent April graduation ceremonies on the Qwaqwa Campus.

In the small village of Ga-Mabotia about 25 km outside of Polokwane, Dr Katlego Mashiane grew up, surrounded by rocky mountains characterised by boulder outcrops, where he interacted with nature from an early age.

He recently obtained his PhD, majoring in Geography, from the University of the Free State (UFS), which was conferred on him during the April graduation ceremonies that took place on the UFS Qwaqwa Campus. The title of his dissertation is Grass nutrients estimation as an Indicator of rangeland quality using satellite remote.

Predicting the presence of biodiversity and nutrients in an area

Based on the principle that diverse grasslands tend to perform better, environmental changes threaten the resilience and services these grassland ecosystems provide. The study examined how many different types of plants and animals can be found at a particular place to enhance our understanding of the ecosystem’s value to humans, and that biodiversity loss will reduce these ecosystem services. Focusing on spatial modelling of grassland diversity, Dr Mashiane specifically investigated the influence of topography and remotely sensed satellite data on species richness and diversity in subalpine environments, and how they are affected by the availability of grass species. To determine this, he used a random forest machine-learning algorithm to find the best information in the data that could be used to estimate the levels of species richness, diversity, and nitrogen in a protected national conservation park.

His study discovered that some data types – such as the near-infrared variable and certain vegetation data (EVI and SAVI) – were especially useful for determining the number and variety of species in a certain area. With this information, scientists can create models that predict the presence of different types of biodiversity and nutrients in an area.

Playing a key role in protecting our natural assets

Equipped with this knowledge, one will be able to understand how to protect and preserve different types of biodiversity and promote the nutritional value of both plants and animals in the environment. “Land managers could use this information for conservation strategies,” states Dr Mashiane, who decided to pursue this study because he was curious about how environmental changes will affect species.

“Grasslands provide important ecosystem services underpinning human well-being, and therefore warrant our protection; I would like to play a role in protecting our natural assets and contribute to understanding our biomes, especially in the context of global change,” he says.

In the next five years, Dr Mashiane plans to pursue further research and mentor other students in his field of study.

News Archive

Harvard couple to present lectures on Biostatistics and Mathematics at the UFS

2015-12-07

Professor Donald Rubin

Prof Donald Rubin (John L. Loeb Professor of Statistics at Harvard University) and Elizabeth Zell (MStat - mathematical statistician in the Division of Bacterial Diseases) will visit the University of the Free State (UFS) where they will present lectures on their respective work.

Over his prestigious academic career, Prof Don Rubin’s 400 publications and 13 books have earned him around 180 000 citations at an h-index of 113. He is one of the most cited statisticians/mathematicians/economists/psychologists in the world over the last 10 -15 years. He has supervised 35 PhD candidates as sole-supervisor, 17 more as co-supervisor, with a further eight in the pipeline.

Prof Rubin who will meet with UFS academics in the Department of Mathematics and Actuarial Sciences will also deliver a lecture: Rerandomisation to improve covariate balance in experiments.

Randomised experiments are the “gold standard” for estimating causal effects, yet in practice, chance imbalances often exist in covariate distributions between treatment groups. If covariate data are available before units are exposed to treatments, these chance imbalances can be mitigated by first checking covariate balance before the physical experiment takes place. Provided a precise definition of imbalance has been specified in advance, unbalanced randomisations can be discarded, followed by a rerandomisation. This process can continue until a randomisation yielding balance according to the definition is achieved. By improving covariate balance, rerandomisation provides more precise and trustworthy estimates of treatment effects.

Prof Rubin received an honorary professorship from the Faculty of Natural and Agricultural Sciences at the UFS.

Elizabeth Zell

The lecture will take place on:
Date: Tuesday 8 December 2015
Time: 16:00
Venue: Albert Wessels Auditorium, Bloemfontein Campus

Zell earned her Master’s degree in Statistics at North Carolina State University, and for more than two decades, was an active bio-statistical researcher in various offices of the Centers for Disease Control (CDC). Since 2013, she has been the Principal Statistician and President of Stat-Epi Associates, Inc. Her 150+ publications have earned her 14 500 citations at an h-index of over 50. She is a Fellow of the American Statistical Association, and, in 2010, she received the Statistics Section Government Award for outstanding contributions to statistics and public health by the American Public Health Association. During her career at the CDC, she earned more than 20 CDC research awards and honours.

She will deliver two lectures at the UFS. The first is entitled A Potential Outcomes Approach to Documenting the Public Health Impact of the Introduction of PCV13 for the Prevention of Invasive Pneumococcal Disease. The topic of her second lecture is: Assessing the Effectiveness of Intrapartum Antibiotic Prophylaxis for Prevention of Early-Onset Group B Streptococcus Disease through Propensity Score Design

Elizabeth’s lectures will take place on:
Date: Wednesday 9 December 2015
Time: 10:45 and 13:00
Venue: West Block 111, Bloemfontein Campus

For more information, please contact Dr Michael von Maltitz at VMaltitzMJ@ufs.ac.za.

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