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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.

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Well-established root system important for sustainable production in semi-arid grasslands
2015-02-24

Plot layout where production and root studies were done
Photo: Supplied

The importance of a well-established root system for sustainable production in the semi-arid grasslands cannot be over-emphasised.

A study of Prof Hennie Snyman from the Department of Animal and Wildlife and Grassland Sciences at the University of the Free State is of the few studies in which soil-water instead of rainfall has been used to estimate above- and below-ground production of semi-arid grasslands. “In the past, plant ecological studies have concentrated largely on above-ground parts of the grassland ecosystem with less emphasis on root growth. This study is, therefore, one of the few done on root dynamics in drier areas,” said Prof Snyman.

The longevity of grass seeds in the soil seed bank is another aspect that is being investigated at present. This information could provide guidelines in grassland restoration.

“Understanding changes in the hydrological characteristics of grassland ecosystems with degradation is essential when making grassland management decisions in arid and semi-arid areas to ensure sustainable animal production. The impact of grassland degradation on productivity, root production, root/shoot ratios, and water-use efficiency has been quantified for the semi-arid grasslands over the last 35 years. Because of the great impact of sustainable management guidelines on land users, this study will be continuing for many years,” said Prof Snyman.

Water-use efficiency (WUE) is defined as the quantity of above- and/or below-ground plant produced over a given period of time per unit of water evapotranspired. Sampling is done from grassland artificially maintained in three different grassland conditions: good, moderate, and poor.

As much as 86, 89 and 94% of the roots for grasslands in good, moderate and poor conditions respectively occur at a depth of less than 300 mm. Root mass is strongly seasonal with the most active growth taking place during March and April. Root mass appears to be greater than above-ground production for these semi-arid areas, with an increase in roots in relation to above-ground production with grassland degradation. The mean monthly root/shoot ratios for grasslands in good, moderate, and poor conditions are 1.16, 1.11, and 1.37 respectively. Grassland degradation lowered above- and below-ground plant production significantly as well as water-use efficiency. The mean WUE (root production included) was 4.79, 3.54 and 2.47 kg ha -1 mm -1 for grasslands in good, moderate, and poor conditions respectively.

These water-use efficiency observations are among the few that also include root production in their calculations.

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