Southern Africa’s ‘water tower’ slipping towards ecosystem collapse

Southern Africa’s “water tower” — the majestic Maloti-Drakensberg mountain range — is slipping towards a state of ecosystem collapse, with grave implications for water security.

According to Dr Ralph Clark, the director of the Afromontane research unit at the University of the Free State, the Maloti-Drakensberg range is the largest provider of freshwater in the region, and its alpine system is crucial to this function. 

An alpine environment is cold, windy, snowy and characterised by low growing-season temperatures and a short frost-free period, according to ScienceDirect.

“But it (Maloti-Drakensberg) is under tremendous pressure from intense communal rangeland degradation. If the alpine system collapses, water production will be detrimentally affected,” says Clark..

The Maloti-Drakensberg is a critical water source area, supporting nearly half of South Africa’s GDP, supplying Gauteng with 34% of its water and Bloemfontein with 70%. 

The problems facing the mountain ecosystem are neither simple nor driven by a single cause, Clark says. “You’ve got immediate local-scale impacts and global impacts such as climate change. When you’re dealing with a mountain system like the Maloti-Drakensberg, it’s about 40 000 km2,” he told the Mail & Guardian.

The mountain system is shared between South Africa and Lesotho, and in South Africa, between three provinces — the Free State, KwaZulu-Natal and the Eastern Cape.

“So you’ve got local actors doing different things, having different impacts that are positive and negative. If you take the Basotho herding situation for instance, you’ve got very, very poor people living in the mountains in a very desperate situation, with herding as one of their only livelihood options, using the alpine pastures in summer.”

But this is not sustainable as the numbers of animals are too big for the available mountain pasture.

“The pressure is high, which leads to a reduction in vegetation cover, which leads to soil erosion. One of the biggest problems is the loss of wetlands in the alpine zone, so your vast sponge systems that basically retain water and release it slowly, become dongas … where the rain just washes away,” says Clark.

“We see a pattern across the Maloti-Drakensberg trending towards what we would call ecosystem collapse … where the system gets so degraded that without major intervention with huge financial costs, you wouldn’t be able to bring it back to what it was.”

The knock-on effects, Clark says, lead to economic and social collapse. 

Tapped out: The Maloti-Drakensberg range provides water to border provinces Gauteng, KwaZulu-Natal and Free State, as well as Lesotho, where Basotho herders also use its summer pastures for grazing. Photo: George Brits/AFP

“Then you start getting migration of poor people from the mountains to the cities.” 

This is already unfolding in a part of Lesotho, where the mountain system is highly degraded. “There is more bare ground than vegetation. The rivers no longer run all year, only after rain, and this has an effect on the Lesotho dams’ project, for example.”

The Basotho herders have few options to draw an income and are affected by economic and political problems. “Covid-19 has added to that with the loss of jobs and remittances from South Africa … so people have to go back to their rural livelihoods.”

There is geopolitical tension along South Africa’s border with Lesotho. 

“It’s almost like a passive-aggressive relationship where the boundaries are in dispute between South Africa and Lesotho, particularly on the KwaZulu-Natal side. 

“Lesotho claims right to the edge of escarpment where South Africa claims up to the watershed, which is a little bit behind the escarpment.” 

These “subdued tensions” lead to the heavy encroachment of Lesotho herders and their livestock into the South African side of the alpine zone.

Clark’s research uses the Mont-aux-Sources mountain as a case study. 

“We’re really trying to unpack these challenges, examine the driving effects, look for alternative livelihood opportunities for herders and work with our Lesotho counterparts in government and research to come up with sustainable solutions.” 

Dr Peter Chatanga, an ecologist at the National University of Lesotho, says the Maloti-Drakensberg plays a significant role not only in supporting rich biodiversity, but in delivering a wide range of other ecosystem services, especially in terms of water resources and livestock grazing. 

“The high-altitude catchments in the region form an essential hydrological watershed

and reservoir for the downstream riparian countries in Southern Africa. The region forms

headwaters of many rivers that also provide water for the Lesotho Highlands Water Project (LHWP) dams (Katse, Mohale and Muela),” Chatanga explains.

The biggest of these rivers is the Senqu (Orange), which is one of the most utilised shared river systems in Southern Africa. The LHWP dams support both the hydroelectric power generation for Lesotho and the transfer of fresh water to the most densely populated and industrialised province in South Africa, Gauteng. 

“The water from this region also plays an important role in the South African agricultural sector because a substantial portion of the agricultural production in the country’s arid regions uses the water from the aqueducts connected to the dams associated with the Senqu (Orange) River,” says Chatanga.

Dams that supply the Lesotho population with water, such as Metolong, also depend on the headwaters in the Maloti-Drakensberg. “However, the water is not only important for Lesotho and South Africa, but also for Namibia as a downstream riparian country.”

Chatanga says the value of the Maloti-Drakensberg in terms of water resources will likely increase, given that the SADC in 2008 predicted that, by 2025, South Africa will face total water scarcity, Lesotho will be water stressed and Namibia will likely experience problems of water availability and quality, especially in the dry season.

“A better understanding of the ecology of the Maloti-Drakensberg ecosystems would enhance the conservation planning and monitoring of these important ecosystems. We can only value and protect what we know and understand,” he explains.

Crop and livestock production provides the primary sources of livelihoods for more than 80% of Lesotho’s population. 

“Livestock production is mainly dependent on the communal rangelands in the grassland found in the Maloti-Drakensberg. As they support the most palatable vegetation, wetlands in the region also form an important livestock grazing resource. The ecosystems in this region also provide harvestable plant products that are used for different purposes, including traditional medicine, wild vegetables and artefacts,” Chatanga says. 

With their peat-forming capacity, the wetlands in the Maloti-Drakensberg contribute to climate regulation by sequestering and storing carbon. Chatanga points out, too, how the mountain range is an important recreation and tourist destination “because of its beautiful scenery. Thus, the region is important at the local, regional and international scales”.

He says over-utilisation, poor range management and poor farming practices (in particular

overstocking and overgrazing) are among the major culprits in the degradation of the range’s ecosystems, including wetlands, particularly on the Lesotho side. “Most of the areas, including the sensitive wetlands, are overgrazed or over-utilised for cropping, leading to their degradation and loss of biodiversity. 

“Although economically important, mining, damming and the associated infrastructure construction have also resulted in the degradation of the ecosystems, as well as increased grazing pressure on the remaining grazing areas. Invasion by alien plants has also been implicated in ecosystem degradation,” says Chatanga.

Climate change, too, looms large. Chatanga says that because of its high altitude, the Maloti-Drakensberg area has recently been reported to be highly vulnerable to climate change.

Across the planet, mountains and polar regions are warming faster than anywhere else, Clark points out. 

“There’s a number of climate change scenarios for South Africa and the take-home story is that our mountains remain crucial for water security in southern Africa, whether we have more rain, less rain or more drought prevalence … There is a strong link between water and regional and national stability.” 

Understanding the alpine system holistically is the first step towards its sustainability and restoration, says Clark, whose research unit is partnering with several institutions of higher learning and policy makers on the continent to expand alpine research, as a better understanding of Southern African mountains as social-ecological systems is needed.

In general, these mountains are largely unexplored by scientists, poorly researched, under-appreciated by economists and politicians despite the valuable public goods and services they provide, and absent from most government policies. 

“We want to push the sustainable development agenda so that our mountains not only retain their catchment value but so we can improve it in the face of climate change and increasing human demand.”

Outside of South Africa, there’s virtually no mountain science capacity, with the exception of Lesotho and Zimbabwe. 

“There aren’t people looking at southern African mountains at the scale that people are looking at the Alps, Himalayas, Andes or Rockies. If you compare us to East Africa, where you’ve got Kilimanjaro and Mount Kenya, we probably lag behind East Africa by 50 years in terms of research capacity, so we’re trying to work towards closing the gap.

“Even our biggest system, the Maloti-Drakensberg, is understudied, but go further afield and even less has been done. Probably the most well-studied mountain in South Africa is Table Mountain,” Clark says.

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