Services – from water and sanitation to baristas and banks – support our lives, but we seldom pause to consider exactly who provides them. Who installed and maintains the pipes and sewers that lead to and from your home or business? How is water managed and treated to ensure its safety? And where does it flow from in the first place?
When it comes to providing the most essential services – supplying air, water, food, energy, and security – we depend on ecosystems. This is why we need to invest in ecological infrastructure in the same way as we would invest in water purification or wastewater treatment works, according to Ashia Petersen, Director of Sustainable Resource Management at the Western Cape Department of Agriculture.
"Ecological infrastructure is basically the infrastructure that is required for healthy, functioning ecosystems," she explains.
Healthy ecosystems contain microbes, fungi, plants, animals, and humans that interact to create an environment for life to flourish. Biodiversity refers to all the different living organisms that produce and consume resources in the giant ecological economy we call an ecosystem.
Biodiversity in agro-ecosystems under-pins water catchment and purification, groundwater recharge, nutrient cycling and soil health, crop pollination, integrated pest management, flood and fire mitigation, and carbon sequestration.
Agriculture is obviously important because we all need to eat. But agriculture in the Western Cape also directly employs more than 200 000 people and exports nearly R80 billion of agricultural and agri-processing products annually. None of this would be possible without biodiverse and healthy ecosystems. Hence, the Western Cape Department of Agriculture prioritises ecological infrastructure management.
Sustainable Resource Use and Management
The Sustainable Resource Use and Management programme within the Western Cape Department of Agriculture includes four sub-programmes: LandCare, Disaster Risk Reduction, Agricultural Engineering Services, and Land Use Management.
Land Use Management strives to prevent the loss of agricultural land to excessive development, while Agricultural Engineering Services assist clients with irrigation, mechanisation, farm-structure planning, and food processing and value-adding. They also design soil-conservation and erosion-protection structures that prevent further resource degradation.
Natural disasters due to extreme weather events driven by climate change seem to be constantly in the news – a sign of pressure on global ecological infrastructure. Disaster Risk Management aims to reduce the risks and impacts of natural disasters such as fires, floods, and droughts.
As we all know, an ounce of prevention is worth a pound of cure, so investment in ecological infrastructure to mitigate natural disasters is money well spent. "One of our risk-management projects is River Protection Works," says Petersen. "We build groynes and weirs. During flood events, these structures slow down the flow of water that causes loss of productive agricultural soil."
Groynes are structures – in this case, gabions – that are placed in rivers to slow water flow, reduce bank erosion, and trap sediments.
River ecosystems are also nurtured by the fourth Sustainable Resource Use and Management sub-programme, LandCare. "LandCare is a community-based and community-led natural-resource management programme," says Francis Steyn, LandCare Manager at the Western Cape Department of Agriculture.
The concept originated in Australia in 1997 and was adopted by the South African government in 1999. LandCare projects have been implemented in all nine provinces.
LandCare is based on six principles: recognising and addressing the causes of natural-resource decline through policies and strategies; fostering community-based and -led natural-resource management; developing sustainable livelihoods; building capacity in governments and communities; developing public-private partnerships; and enabling feedback on policies.
The themes of LandCare are WaterCare, SoilCare, VeldCare, and JuniorCare. "Our WaterCare projects are restoration of the natural environment," says Steyn. "To get there, the first thing we have to do is alien clearing."
Aliens assaulting our environment
A recent study of the Western Cape water-supply system estimated that upland and riparian alien vegetation currently reduces water yields by 7%. This figure could escalate to as much as 23% if aliens are not controlled.
Alien trees along riverbanks have been shown to cause significant reductions in stream flows. For example, studies in the Western Cape found that dense stands of black wattle reduced stream flows by 45 – 135 mm per year, eucalypts reduced flows by approximately 200 mm per year, and mixed pines reduced flows by 85 – 433 mm per year.
Stream-flow reductions are not only caused by trees on the riverbanks. Researchers showed that clearing dryland pines increased stream flows by 343 mm per year – and we know that every drop counts.
"Invasive alien plants in the riparian zone don’t just impact the water availability," says Petersen. "They also impact the soil stability of the riverbank."
Steyn explains that alien-infested rivers tend to develop steep banks that are vulnerable to erosion and flooding. To make matters worse, aliens can block rivers, even causing them to change course. "When we take out the aliens, the river starts meandering again. It’s wider, but the risk of it jumping its bank is much less."
Besides guzzling water and boosting floods, alien vegetation escalates the risk of veld fires. Many alien trees, notably pines, wattles, and eucalypts, combine abundant biomass with high flammability to create the perfect conditions for intense blazes that are difficult to control.
Multi-dimensional sustainability
"The critical part of alien clearing is that you can't clear for one year," says Petersen. "You need to clear for 15 – 20 years to exhaust the seed bank."
This is why alien clearing is only the start, says Steyn. "We want to take it from the current 500 tonnes per ha of alien vegetation to something that’s completely indigenous and natural. So once we take out the aliens, we follow up, and we start restoring."
Part of restoration involves planting indigenous trees. These are mostly grown from seed that was collected from trees in the same river system. Once the indigenous trees establish, they prevent the germination of aliens and reduce the need for clearing.
Nonetheless, alien clearing is an expensive, long-term commitment that requires people to work together. "One of the principles of LandCare is partnerships," says Steyn. The Western Cape Department of Agriculture receives LandCare funding from national and provincial sources, and collaborates with many other organisations and initiatives, including water users' associations and catchment management agencies, Cape Nature, the City of Cape Town, Working for Water, and the World Wide Fund for Nature.
Steyn stresses that the LandCare vision is not limited to the ecological benefits of clearing and restoration. These activities create employment, while the alien biomass is converted into anything from high-quality boards for carpentry to wood chips for energy generation and soil amendment. He also sees huge tourism potential for restored rivers, as well as the possible sale of biodiversity credits.
As is so often the case with ecological projects, the biggest challenge is funding. The Western Cape Department of Agriculture provides financial assistance for the initial clearing of aliens, but thereafter landowners must take up the baton.
Increased water availability and security remain the biggest pulls for landowners, but Steyn has noticed that restoration offers more than just financial rewards. "The thing that farmers speak about most afterwards is the ecosystem – they see all the life that's returned to the river. Money matters, but farmers are naturalists."
For much more about Sustainable Resource Use and Management, including other LandCare themes, download Abundant Harvest, a free publication available from www.elsenburg.com.
