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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 launches projects to assist communities and current students
2011-03-16

Prof. Jonathan Jansen, UFS Vice-Chancellor and Rector and Mr Rudi Buys, Dean: Student Affairs, with learners at the  Bloemfontein-Oos Intermediary School.
Photo: Stephen Collett

The University of the Free State (UFS) has launched four exciting projects set out to improve the circumstances of its current and prospective students. These include a project that will honour dedicated and influential educators.

These community service projects in the starting blocks are: the UFS Schools Partnership Project, Extreme Make-over Project, Great Teachers Project and the No Student Hungry Campaign.
 
The Schools Partnership Project aims to support 21 schools across the Free State in helping them to become top achievers in the next three to five years. The schools involved were selected last year, after which the groundwork for the project was finalised. Although it mainly focuses on improving scholars' results in mathematics, accounting, physical sciences and English, it is also custom-designed according to the specific needs of the school, as indicated by the respective governing bodies beforehand. As a bonus, scholars of the schools involved will be given an opportunity to be introduced to student life; something Dr Choice Makhetha, UFS Vice-Rector: External Relations (acting), claimed to be of great importance. “We will invite Grade 10 to 12 learners to winter and summer schools being presented at the university. We will connect learners with students (one student adopts one learner for the day) for them to experience campus life. Grade 12 learners will also receive an invitation to the May 2011 graduation ceremony,” Dr Makhetha said.
 
Adding to the university's involvement at schools on local level, the newly upgraded Bloemfontein-Oos Intermediary School with its 112 UFS-sponsored tables will officially be revealed by the end of April. Although this school's upgrade showcases the power of partnerships, it is of special importance to the university, as it also marks the first school to receive an extreme make-over as part of the 'Extreme Make-over for Schools Project'. This project, in conjunction with the local business community, university staff and students, the community, the Department of Basic Education and SIFE (Students in Free Enterprise), is considered to be a flagship project of the Vice-Chancellor and Rector, Prof. Jonathan Jansen. Part of the project’s agreement includes visits from a group of about 100 students representing campus initiatives such as the UFS’s Kovscom, Rag and SIFE, which will contribute to the improvement of the schools' resources within a period of 10 – 15 weekends. “We invite support from all corners. South Africa has a business community committed to improving the social circumstances of its community and we plead that they also come to the rescue of the Bloemfontein-Oos Intermediary School,” said Dr Makhetha.
 
By spreading a 'can do' attitude, the UFS aims to honour noble and remarkable teachers across the country by means of its 'Great teacher's project'. Through the project, fellow citizens are encouraged to submit their stories on their former or current teachers’ dedication and their positive impact which are often overlooked. The panel of seasoned education scholars and practitioners will select the top 500 stories based on the stories' clarity, distinctiveness, plausibility and affectability, which will be perpetuated in a book called 'Great Teachers', to be released at the end of this year. Proceeds are destined to serve as bursaries for students who wish to pursue a career in education. According to Prof. Jansen the ideal teacher is: “Somebody who was among, but stood out above, their colleagues, a person who made a lasting impact long after the details of subject matter content of examination preparation were forgotten.”
 
Regardless of this exceptional effort of supporting schools across the province, the UFS remains committed to its students and their social welfare by means of the 'No student hungry' campaign. This project provides financially challenged students the opportunity to purchase food from the Thakaneng Bridge on the Main Campus in Bloemfontein by using their student cards at two selected kiosks serving balanced meals. The project, which is under the guardianship of Ms Grace Jansen and Dr Carin Buys, relies solely on several fund-raising projects across the country. These women are the respective spouses of the Rector and Dean: Student Affairs, Mr Rudi Buys. According to Ms Jansen this initiative was proposed after UFS staff reported that many students were struggling to concentrate on their studies due to hunger pangs. Although the campaign recognizes students with strong academic records, it doesn't overlook those who need a food bursary which might result in them dropping out. Ms Jansen said as the external funds gathered increase, so will the amount of students being supported by the project. “The plan is to continue until the fate of hungry students had come to an end,” she said.
 

Media Release
14 March 2011
Issued by: Lacea Loader
Director: Strategic Communication
Tel: 051 401 2584
Cell: 083 645 2454
E-mail: news@ufs.ac.za

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