By Louise Stafford
As the effects of climate change intensify, our precious water resources are becoming strained. This puts people and nature at risk, hence the need to urgently address the quantity and quality of water flowing through rivers, including removing invasive species.
The Cape Region in South Africa is staring at such a crisis brought about by invasive pine trees, which are replacing native trees in its iconic rivers, wetlands and catchments. By consuming vast amounts of water, the thirsty and fast-growing pines invade and ultimately strangle river systems and hinder the natural and nourishing flows, thus endangering biodiversity and water security.
The reduced flows in the rivers that feed major water supply dams, such as Theewaterskloof, one of Cape Town’s primary reservoirs, threaten supply to downstream users. Healthy rivers, wetlands and catchments are the sources of water for millions of people in the region. Additionally, these ecosystems provide resilience against impacts of climate change such as droughts and floods.
Equally concerning are the impacts of these trees on the delicate balance of life sustained by the river ecosystems. There are creatures beneath the surface of the water that rely on swift and stable river flows to thrive. The diversity of habitats and niches in healthy rivers accommodates a variety of plants and animals that are well adapted to life in flowing water. For example the Cape galaxias fish, are are drift-feeders that pluck their food from currents as it drifts by. Cape ghost frog tadpoles have powerful sucker-mouths adapted to grazing algae that grows in fast flows, and black fly larvae have nets on the ends of their legs to filter their food from the flow.
Where pines reduce flows, or if rivers dry up completely, food supply and habitat for these and other species will be reduced, and they could disappear forever. Losing them would reduce the overall health of the aquatic ecosystem, irreversibly diminish the region’s biodiversity and erode the ecosystem services these rivers provide. More than that, most of these species are endemic to a particular river system, so if we lose them in this region, we lose them for good.
Therefore, to restore the rivers’ flows, for the benefit of people and nature, these invasive pine trees need to be managed to restore natural ecosystems. By tackling invasive species, we can protect South Africa’s biodiversity, enhance water security, and ensure that the region’s natural beauty and resources are available for future generations.
Recognising the scale of the threat, The Nature Conservancy in partnership with national and provincial government, CapeNature, the City of Cape Town, WWF and the private sector is implementing an ambitious restoration project by removing invasive pines from region’s water catchments. This initiative aims to clear invasive trees from over 50,000 hectares in the water catchment by 2026 and maintain those areas to prevent the invasive trees from growing back. As of October 2024, 32,347 hectares have been cleared and follow-up clearing efforts have been conducted on 25,124 hectares to prevent regrowth and maintain cleared areas.
Approximately 17.6 billion litres of water is reclaimed annually, amounting to an additional 48 million litres each day flowing into rivers and dams. These gains not only improve the availability of water for humans but also enhance water quality and restore habitat for vulnerable, rare or sensitive species, such as the Giant redfin, Cape ghost frog and other riverine species that depend on strong, stable flows to thrive.
To effectively combat the escalating crisis of water scarcity in the Cape Region, we must act decisively and collaboratively. The ongoing restoration efforts led by The Nature Conservancy and its partners through the Greater Cape Town Water Fund serve as a powerful example of what can be achieved when partners unite for a common cause. The time for action is now – let us ensure that our rivers continue to flow freely, nurturing both people and nature in this beautiful region. Together, we can make a difference.
* Louise Stafford is TNC South Africa Country Director.
** The views expressed do not necessarily reflect the views of IOL or Independent Media.