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31 October 2021 | Story Elsabé Brits
Grassland

In the vast, flat grasslands of South Africa a host of magnificent plant and animal species flourish, but not all of them are large. Insects and spiders share the landscape, and they are sometimes the uncelebrated heroes of a fragile ecology.

Walking through grasslands one often ignores what is under our feet, but these creatures are vitally important for the wellbeing of any ecosystem.

Grasslands are the dominant vegetation in the central parts of the country, covering most of the Free State and Gauteng and large parts of the North West, Mpumalanga, KwaZulu-Natal and the Eastern Cape, explains Prof Charles Haddad from the Department of Zoology and Entomology in the Faculty of Natural and Agricultural Sciences at the University of the Free State (UFS).

Insects fulfil a myriad of ecosystem functions and deliver crucial services in grasslands. They are the most important group of pollinators, such as bees, flies, and beetles, and are critical to the breakdown of plant and animal waste, especially flies and beetles. They are predators and parasites of other invertebrates, especially spiders, beetles, wasps and flies. The more species in an ecosystem, the greater the number of interacting organisms that can contribute to food webs.

Unfortunately, grasslands are the most threatened biome in South Africa, largely as a consequence of historical agricultural expansion of crop and livestock farming. More recently, urban development, invasive plants and silviculture have impacted on the remaining natural grasslands.

“Little is known about the impact of these activities on terrestrial biodiversity. The presumption is that the destruction and fragmentation of natural grassland reduces the natural vegetation available to indigenous organisms. This creates problems for insects to find suitable plants to feed on, which has a negative impact on their predators and parasites.

“Most anthropogenic influences affect indigenous biodiversity negatively, with very few exceptions. Generally, it is exotic invasive species that benefit the most from disturbance, habitat changes or destruction,” says Prof Haddad.

Spiders

More than 900 species of spiders have been recorded in our grasslands and some 2 300 in the country. Spiders are predators of other invertebrates, especially insects, and play an important role in the natural control of their populations.

They are very resilient to disturbance but are susceptible to chemicals used on crops, the effects of alien plants, and competition with exotic spider species, says Prof Haddad.

Among the interesting spider species one can find in grasslands is a rich diversity of trapdoor spiders, which live in burrows in the ground. Many of them have narrow associations with specific soil types and are often good bioindicators for conservation management.

Some plant-dwelling spiders are uniquely adapted to living on grasses and have slender, pale bodies to camouflage themselves on the stalks of grasses. In contrast, tree-dwelling spiders are often brown with tubercles on their bodies to blend in with the bark of trees to help them ambush their prey, says Prof Haddad.

Termites

Termites are some of the most populous animals on Earth, and the effects they have are most profound in the grasslands. Termites are one of the few animals that can break down cellulose from dead wood and grass. This is made possible through their symbiotic association with tiny microorganisms in their alimentary canal, such as protozoans and bacteria. The microorganisms secrete the enzyme cellulase, which the termites cannot produce themselves, allowing for the breakdown of cellulose in the ingested plant material and the release of the component nutrients for use by the termites. Therefore, these insects play an integral role in the reintroduction of nutrients from the dead plants into the soil.

This enables them to utilise the molecules in the grass that would have otherwise been inaccessible. Their faeces, therefore, contain broken-down nutrients that the roots of plants can absorb.

Many termite species live in underground nests that are great in aerating the soil. Others build large mounds which are extensions of the nests above the soil surface. These mounds, particularly those of the snouted harvester termites, are a familiar feature in most grassland landscapes in the country. These nests and mounds also offer shelter to other organisms, such as spiders, scorpions, lizards, snakes, millipedes, and various insects.

Termites are an important food source for enigmatic animals such as the aardvark and aardwolf, as well as some spiders and beetles, says Prof Haddad. 

Mosquitoes 

Liezl Whitehead, a master’s student in the Department of Zoology and Entomology at the UFS, explains the role of how even mosquitoes are essential.

Mosquitoes are vitally integrated into the ecosystem even as larvae, where they feed on aquatic microorganisms, thereby affecting species interactions and ecosystem dynamics within the aquatic habitat.

Adult mosquitoes feed on nectar as their main food source, and in the process also serve as plant pollinators. Many female mosquitoes do, however, require a blood meal for egg production, where they then transmit a multitude of pathogens. Interestingly, these pathogens play a vital role in the ecosystem, where they help to regulate host population sizes, thereby maintaining the integrity of the ecosystem.

“In recognising the significance of all forms of life, one also realises that mosquitoes play an essential role in the life cycle of numerous other organisms, including protozoans [single-celled microscopic organisms], nematodes [often referred to as roundworms, but they are not closely related to true worms], and mites that depend on mosquitoes for their development and dispersal.

The abundance and widespread nature of mosquitoes contributes to their significant role in the grassland food chain, where the larvae are consumed by countless aquatic organisms, including insects, fish and amphibians. The adults are consumed by a multitude of arthropods and vertebrates, including dragonflies, birds and bats.

“Their elimination from the ecosystem would thereby impact multiple processes within the ecosystem, affecting food webs, pollination and the presence of many other associated organisms,” Whitehead adds. 

A vital food source, urgent protection needed

Prof Liesl van As, Head of the Department of Zoology and Entomology at the UFS says that although the Grassland biome covers an area of 339 237 km2, less than 2% is formally protected. In 2004, the National Spatial Biodiversity Assessment (NSBA) identified the Grassland biome as the most threatened habitat, with more than 30% already irreversibly transformed. A year later, the Grassland Biodiversity Spatial Priority Assessment identified 37% of the land as being important for conservation and suggested that 12% needs to be under formal protection by 2028.

Most of the South African grassland literature refers to the almost 400 plant species, the 34 endemic mammals, and the dozen or so globally threatened bird species, with almost no mention to representatives of the Arthropoda (including spiders, termites and mosquitoes).

Invertebrates are the main components of faunal diversity in grasslands, playing substantial roles in ecosystem processes, including nutrient cycling, pollination, and being a vital food source in food webs (Die een se dood is die ander een se brood).

“These invertebrate communities are heavily dependent on plant diversity and production within a given ecosystem, but for some reason, they don’t get the full recognition and attention compared to the larger animals. Maybe it is because they are not so visible due to their smaller size?

“A visit to www.grasslands.org.za and the Grassland Society of Southern Africa draws our attention towards the fact that although progress has been made in the awareness of the sensitivity of grassland habitats, gaps still exist concerning the biodiversity of the remaining natural fauna. To follow up on this, I am of the opinion that when it comes to invertebrates, such as the spiders, termites and mosquitoes we are now writing about, knowledge and public awareness (citizen science) is contributing to reducing this gap” says Prof Van As.

According to her, in their department, a number of colleagues from Animal Behaviour, Arachnology, Nematology, Applied Agricultural Entomology, Environmental Entomology and Dipterology, to name a few, have been involved in research projects for the past few decades, with a focus on the grassland area, closer to home.  Through their effort and contributions, they are making a scientific difference. 

News Archive

UFS welcomes Prof Francis Petersen as new Vice-Chancellor and Rector
2017-04-02

 

Prof Francis Petersen takes up office as the 14th Vice-Chancellor and Rector of the University of the Free State today.
 
“On behalf of the UFS Council and the university community, I would like to welcome Prof Petersen to the university. He brings to the UFS a distinguished academic record, confident leadership, innovative thinking, and an understanding of the extent of the challenges being experienced by universities in the broader South African context,” says Mr Willem Louw, Chairperson of the UFS Council. 
 
“I am excited to join the UFS and look forward to meeting the university community, to get to know the three campuses, and to engage with staff and students. In a way, it was a natural progression for me to be appointed in this position, having been Dean of the Faculty of Engineering and the Built Environment at the University of Cape Town (UCT), and then Deputy Vice-Chancellor: Institutional Innovation at the same university.  On the other hand, I believe that universities in South Africa need strong and innovative leadership. I would like to make a contribution to the higher-education system in this regard.  Moreover, I regard the UFS as a very good university, and see my challenge in taking the UFS to the next level,” says Prof Petersen.
 
“Challenges and making a difference motivate me – whether complex or simplistic, the opportunity to be able to provide solutions and taking people with me while developing these solutions, is what ultimately motivates me.”
 
“It is important that different viewpoints are respected. The UFS must be a place where everyone feels welcome. There must be a strong sense of belonging; staff and students must feel they are making a contribution to the university,” he says.
 
According to Prof Petersen, the major challenge for the university is its institutional climate.  “My focus would be to strive towards creating an institutional climate of inclusivity, respect for one another, valuing diversity in all its forms, and to make the university a welcoming place. The UFS is in the process of developing an Integrated Transformation Plan (ITP) that will serve as the road map to address the institutional climate challenge, but will also assist (if implemented effectively) in excelling the UFS in areas of teaching and learning, research and innovation, and community engagement through scholarship,” says Prof Petersen.

“I am a good listener, I am outcome-based, and my vision for the university includes diversity, inclusivity, and academic excellence,” he says.

Prof Petersen was born in Oudtshoorn and grew up in Malmesbury in the Western Cape, where he also matriculated. He graduated from Stellenbosch University with a BEng (Chem Eng), MEng (Metal Eng), and PhD (Eng) degrees and completed a short course on Financial Skills for Executive Management. He is a recipient of the Ernest Oppenheimer Memorial Trust Award for research excellence, and was visiting professor at the Cape Technikon and extraordinary professor in the Department of Chemical Engineering at Stellenbosch University. He is a regular reviewer of journals, and member of a range of editorial boards for international journals. He is also a registered professional engineer with the Engineering Council of South Africa and a Fellow of both the South African Institute of Mining and Metallurgy, and the South African Academy of Engineers.

 He brings to the position of Vice-Chancellor and Rector his extensive experience of management in both the industry and academic sectors. He has been the executive head of strategy at Anglo American Platinum and head of the Department of Chemical Engineering at the Cape Technikon (now Cape Peninsula University of Technology). Among others, he previously served as member on the Board of the Council of Scientific and Industrial Research, the National Advisory Council on Innovation, and the Council of the Academy of Science of South Africa.

 Prof Petersen is married and has two sons. He was appointed by the UFS Council at the end of 2016 after Prof Jonathan Jansen stepped down as Vice-Chancellor and Rector on 31 August 2016, serving in this position since July 2009. Prof Nicky Morgan, Vice-Rector: Operations at the UFS, has been acting Vice-Chancellor and Rector since 1 September 2016.

 

Released by:
Lacea Loader (Director: Communication and Brand Management)
Telephone: +27 51 401 2584 | +27 83 645 2454
Email: news@ufs.ac.za | loaderl@ufs.ac.za
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