From ruin to recovery:
Restoration in the Nuwejaars wetlands
When a dense stand of invasive trees was removed in the Nuwejaars wetlands, there seemed to be little hope for a recovery.
The trees were so large, and were growing so closely together, it was impossible to see just how degraded the area was before the clearing began. With funding support from WWF South Africa, with co-funding from the Overberg District Municipality (ODM), contractor Gerty Holtzhausen and her team removed the trees in the wetlands all along the Nuwejaars River, close to Africa’s southernmost tip.
Once cleared, Nuwejaars Wetlands Special Management Area conservation managers Erica Brink and Eugéne Hahndiek could finally see the extent of the loss of natural systems on the site. Eugéne says,
“What we saw was so severely degraded that we didn’t think it would be able to recover, and we weren’t sure the ecosystem functioning would ever return.”
And yet, only two years after the clearing work started in this section, the incredible natural world here surprised everyone – even the botanical experts.
A six-hectare area in particular was found to be so impacted by the alien plants, that there didn’t seem to be any hope. It proved to be the ideal site to test restoration activities – which the Nuwejaars team called ‘shrub clusters’.
Eugéne says, “We believed that developing small clusters of shrubs and wetland plants in the degraded area would create mini refuges and micro-climates. And that could provide a stepping-stone corridor through the landscape.”
The team removed big trees off an area of 151 hectares – approximately the size of 151 rugby fields over two years.
On top of that 295 hectares of fynbos and wetland habitat was cleared of invasive species that were less densely infested – including the area where a fynbos species new to science was recently discovered, called the Nuwejaars Lily (Cyrtanthus novus-annus).
Three shrub clusters were put in place – which are essentially dense clumps of shrubs and indigenous trees. The team used plants sponsored by Gerrit Wagener of Redford Beverages and bought from the Grootbos Nursery, and others transplanted from neighbouring vegetation. They were surrounded by densely packed brush to prevent any livestock from grazing on the growing plants.
On the other degraded areas, Erica, Eugéne and Gerty and her team introduced other rehabilitation activities, to prevent further loss of the habitat, and to hopefully restore ecosystem services.
Here’s what they did:
Mild bank erosion control
When invasive plants are removed along riparian edges, the riverbanks are exposed and become eroded. This can lead to erosion. So they planted palmiet (Prionium serratum) cuttings in the water. Palmiet is natural to the area, and is a known ecosystem engineer – adapted to both floods and fire, purifying water and sequestering carbon.
Gully erosion control
When surface water runs fast after a large downpour, it can lead to erosion along drainage lines. These can become unstable channels. So they used brush – biomass from the cut invasive trees – to create a filter to trap silt and organic matter normally carried by flood waters. This in turn would slow down the speed of the runoff water.
Sheet erosion control
Some mild sheet erosion had also become evident. This is when thin layers of soil are slowly removed by wind and water. Here there was little vegetative cover. So the team transplanted wetland species from the surrounding area to provide protection and cover.
What the experts then found
In order to see how vegetation recovers over time, it needs to be monitored. This work is largely in Erica’s capable hands. She installed fixed-point photography stands in monitoring blocks, to capture changes in vegetation composition and cover. Photos are taken every three months – including drone footage.
And then the botanical experts undertake regular surveys to capture the changes. Sean Privett and Rebecca Dames of the Grootbos Foundation were called in. Both are extremely knowledgeable on wetlands and fynbos habitat.
According to Sean, “Now that the control blocks have had initial alien clearing within them, they are showing incredible signs of recovery. With a more open canopy, it has allowed natural species to grow and establish.”
He said there were fantastic, and surprising species which emerged after the alien clearing activities, without any further intervention from the Nuwejaars team. In one block, a geophytic species called Aristea Africana emerged. Sean says, “The presence of geophytic plants means that despite the block being previously dominated by alien plants, the fynbos seedbank within the soil was still intact.” Incredible spring bulbs also emerged, including Gladiolus tristis.
He added, “The restoration of the wetlands system has been incredible, with the presence of riparian species also establishing themselves. The removal of alien plant species is the most crucial part of any restoration project, as often fynbos is resilient enough to come back after such disturbance.”
Clear and present danger
Despite the incredible natural recovery of the area with a little bit of human help along the way, the danger is still very much present. Sean says, “Invasive plant species seedbank can remain in the soil for more than 100 years, and therefore clearing initiatives will need to be ongoing to ensure these areas remain pristine.”
With the help of WWF South Africa and the ODM, that’s the team’s focus for the next year. Seedlings, especially of Acacia saligna (Port Jackson) will be removed in sites already cleared. And new, as yet uncleared areas will be added to the project site.
Decade of Ecosystem Restoration
Eugéne says, “The work here at Africa’s southernmost tip shows that nature can restore herself, if given a chance to do so. In the midst of the United Nations Decade on Ecosystem Restoration, these activities can add up to address these huge global threats, including climate change and the next mass extinction. With the support of incredible donors and partners, we’ll continue to play our small part to make this world a better place!”
Every day we ...
Access our biodiversity
If we want to reach social and environmental sustainability, the Nuwejaars Wetland Special Management Area must achieve economic sustainability.
Teaching about nature
School outings are now being hosted to the Nuwejaars Wetlands SMA, where children can connect with this wondrous, intricate natural world.
Traditionally private landowners in the Overberg have made their income from agricultural activities, like grain and livestock farming.