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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

Open letter from Prof Jonathan Jansen to all UFS students
2014-02-22

Dear Students of the University of the Free State

In the past four years there has emerged a new consensus on the three campuses of the University of the Free State (UFS) about the things that divide us – such as racism, sexism and homophobia. Students and campus leaders have worked hard to develop this new consensus in residences and in the open spaces on campus. There can be no doubt that new bonds of friendship have developed across the markers of race, ethnicity, class, religion and sexual orientation. I bear witness to these new solidarities every day on the campus.

You chose a white student to head up the transformation portfolio on the SRC. You chose a black captain to head up the university’s first team in rugby. You chose a white “prime” as head of residence to lead a predominantly black men’s residence. You chose a South African woman of Indian descent as Rag Queen and last week, a black student from Cape Town as the men’s Rag winner—choices not possible and never made before in our campus history. Many of you have intimate friends who come from different social or cultural or religious backgrounds. You learn together, share rooms together, pray together and party together. In other words, in the day to day workings of this university campus, you have demonstrated to campus, city and country that we can overcome the lingering effects of racism and other maladies in this new generation. You have helped create a university community inclusive of people of diverse religions, abilities, class and sexual orientation.

I have said this repeatedly that from time to time this new consensus will be tested – when a minority of students, and they are a small and dwindling minority, still act as if these are the days of apartheid. And when that consensus is tested as it was this week, and as it will be tested in the future, only then we will be able to assess the strength and durability of our progress in creating a new South African campus culture of human togetherness based on respect, dignity and embrace.

The real test of our leadership, including student leadership, is how we respond when our transformation drive is threatened.

Let me say this: I have absolute faith in you, as students of this great university, to stand together in your condemnation of these vile acts of violence and to move together in your determination to maintain the momentum for the Human Project of the University of the Free State. We have come too far to allow a few criminals to derail what you have built together in recent years.

There will, no doubt, be unscrupulous people on all sides of the political spectrum wanting to milk this tragedy for their own narrow purposes. There will be false information, rumours and exaggerations by those who wish to inflame a bad situation to gain mileage for their agendas. That is inevitable in a country that is still so divided.

I ask you, through all of this, to keep perspective. Two or ten or even twenty students behaving badly do not represent 30,000 students; a minority of violent and hateful persons do not represent the ideals, ambitions and commitments of the majority. At the same time, let us be realistic – anyone who thinks you can drive transformation without resistance clearly does not understand the difficult process of change.

The events of the week remind us, however, that we still have a long road to walk in deepening social and academic transformation at our university. Yes, we have invested hundreds of hours in training and mentorship; we have created new structures – such as the Institute for Reconciliation and Social Justice – to capture the energy and imagination of students driving transformation; we have created many opportunities for students to study and travel on this and other continents to enable cross-cultural learning; we have established formal and informal opportunities to dialogue about difficult issues on and off campus between students and their leaders; and we crafted new curricula to enable teaching and learning on the big questions of our times.

But this is clearly not enough, and so I have decided on the following immediate next steps:
  1. We will meet for several hours next week to think about how we can deepen the transformation of our university after this terrible incident.

  2. We will arrange a University Assembly on the events of the past week so that we speak with one voice on human wrongs and to re-commit to human rights and we will continue with open forum discussions during the months to come.

  3. We will review the entire spectrum of programmes, from orientation to residence life to the undergraduate curriculum, to determine how effective our interventions really are in reaching all students with respect to basic issues of human rights.

  4. We will review our media and communications strategy to determine how far and deep our messages on human rights travel across all sectors of the university community. In this regard it is important that the campus be blanketed on a regular basis with our condemnation of human wrongs and our commitment to human rights.

  5. We will commission the Institute for Reconciliation and Social Justice to review the events of the past week and make recommendations on how we can improve the campus environment so that all students are protected from harm inside residences, classrooms and in open spaces of the campus.

  6. We will take the questions raised during this week into the academic community and to the general staff of the university so that all personnel also engage with our own roles and responsibilities with respect to campus transformations.

  7. We undertake to make annual report-backs on transformation to all stakeholders in public forums so that students and staff and external communities can track the progress of the university on matters of human rights on campus.

I wish to thank my staff for acting firmly as soon as this tragic event came to our attention. We worked through the night to find and identify the perpetrators. We traced the two students and immediately handed them to the police. They were expelled. And throughout this process we offered counselling and support to the victim of this violent act.

The two former students were expelled and will now face justice in the criminal courts. It is hoped that in the course of time they will come to their senses and seek restoration and reconciliation with the student they so callously harmed. They are not part of the university community anymore.

That is the kind of university we are.

Jonathan D Jansen
Vice-Chancellor and Rector
University of the Free State
20 February 2014

 
Note: The use of the word ‘campus’ refers to all three campuses of the UFS, namely the Bloemfontein Campus, South Campus and Qwaqwa Campus.

 

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