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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

African Student Affairs Conference a huge success
2011-05-24

 
Mr Rudi Buys, UFS Dean of Student Affairs, Mr. Folabi Obembe, Managing Director of Worldview International, Ms Birgit Schreiber, Director of the Centre for Student support services at the University of the Western Cape, Dr. Augustinah Duyilemi, Dean of Student Affairs at the Adekunleh Ajasin University in Nigeria, Dr. Christina Lunceford, assistant Director for the Centre for Research on Educational Access and Leadership at California State University in America, and Prof. Cecil Bodibe, student affairs veteran and consultant.
Photo: Earl Coetzee

The African Student Affairs Conference (ASAC), which took place on our Main Campus last week, was a major success, with two days of lectures and discussions and two pleasant social gatherings, where delegates had the opportunity to get to know each other.

The conference, hosted on African soil for the first time, and co-hosted by the University of the Western Cape (UWC), started on Wednesday 18 May 2011 with an informal welcoming session. Delegates got to meet each other and Mr Rudi Buys, UFS Dean of Student Affairs, explained the meaning of South African words like "kuier" and "lekker'.

The official start of events took place on Thursday 19 May 2011, in the Reitz Hall in our Centenary Complex. The conference was attended by delegates from universities across the continent and aimed to place the focus on issues relating to student affairs in an African context.

Delegates shared and exchanged strategies, ideas and resources, and discussed issues related to the work of student affairs professionals. The conference hoped to promote an exchange of best practice and assist attendees in identifying successful programmes.

Among the topics discussed on the first day, were “Constructing Post-Conflict Democracy on campus: a case study of transformation of student governance and political engagement as post-conflict intervention”, by Mr. Buys, and a discussion on ways in which social and online media can be used to ease the challenges of student interaction, development and support, by Ms Birgit Schreiber, Director of the Centre for Student Support Services at UWC.

A panel discussion, led by Mr Buys and several members of our Interim Student Council (ISC), discussed the specific challenges faced at the UFS.  The importance of buy-in from role-players in decisions taken by University management in order to ensure their success, was discussed, using the UFS and our recent changes as an example.

The successful integration of residences on campus inevitably came under the spotlight and the recently resolved Reitz-saga was named as a catalyst in getting students less apathetic and more involved in attempts at creating racial and social harmony.

Dr Christina Lunceford, Assistant-Director of the Centre for Research on Educational Access and Leadership at California State University, presented a paper entitled A National Approach to Building Capacity in Student Affairs in South African Higher Education.

She commented on the fact that there is little or no philosophical framework or explicit theory that informs practice of student services in South Africa.

According to Dr Lunceford, student development should be a key concern for every department or unit within student services and emphasized the need for a centralized student development unit at each university.
She also touched on the need for institutions to implement support from international student affairs professional associations, professional development for student affairs practitioners, the utilization of technology to support professionals in the field, and working with international partners to explore future opportunities, as ways in which student affairs can be used to drive performance and change at universities.

The conference continued in the Scaena theatre on Friday 20 May 2011, with presentations by Dr Augustinah Duyileme, Dean of Student Affairs at Adekunle Ajasin University in Nigeria, and Prof. Bobby Mandew, Executive Director of Student Affairs at the University of Johannesburg (UJ).

Dr Duyileme presented a paper on the challenges faced by Nigerian universities with regard to student conflict and protests, which often turn violent, and how such violence can be curbed through proper planning and management.

Prof. Mandew presented a very well-received presentation on UJ’s successful off-campus housing initiative, which involves home-owners and business owners in the areas surrounding their campuses.

Their approach demonstrated how proper planning can prevent problems associated with over-population in private homes and conflict with neighbours of the university, usually related to an influx of students into residential neighbourhoods.

This problem is faced by many universities, as more and more students flock to universities on the continent and campus residents cannot accommodate them.

The conference came to a close on Friday, with most delegates agreeing that the exchange of knowledge which took place was extremely valuable.

Ms Deborah Lahlan, of Nigeria, said: “This is an important conference for Africa and it should become a regular event.”
 

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