Invasive alien plants increase the intensity of veld fires, and certain parts of South Africa are extremely vulnerable to large-scale runaway fires.

Water shortages, loss of arable land, worsening veld fires, declining grazing quality, and lower cash crop yields all have one thing in common: invasive alien plants.

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There is hardly a farm in South Africa that has not been negatively affected in some way by these plants. Species such as slangbos (Seriphium plumosum L.), silver wattle (Acacia dealbata), and various species within the Eucalyptus and Lantana genera can cause significant problems for hardworking livestock and crop farmers, as well as game ranch owners.

At best infestations of invasive alien plants cause loss of agricultural potential, while bankruptcy, fines and farm repossessions are some of the worst outcomes. Although clearing these plants requires hard work and careful management, there are opportunities to recover at least some of the costs of clearing.

Woody invasive plants, such as the silver wattle, reduce the veld’s carrying capacity by replacing grasslands.

The impact of invasive plants

Invasive alien plants consume more than 6% of South Africa’s freshwater resources. They invade arable land at an alarming, ever-increasing rate. In many areas of the country they make commercial farming more difficult, or even impossible. In the northern bushveld areas of South Africa, encroached bush now covers a third of the entire landscape and grows at a rate of 0,6% of the total landmass per year.

In addition to posing a threat to commercial farming, invasive alien plants also increase the intensity of veld fires, such as the fires that occurred in Cape St Francis, Knysna and Cape Town within the past two years. Without urgent intervention, veld fires in certain parts of South Africa could reach the same intensity as the Australian veld fires that devasted large parts of the country late last year and earlier this year.

However, the damage invasive alien plants can cause is not the only aspect landowners should be concerned about. The National Environmental Management: Biodiversity Act, 2004 (Act 10 of 2004)holds the landowner responsible for the management of these plants. In many cases, their presence on private land is strictly controlled or illegal, and landowners could run the risk of being penalised with hefty fines of up to R10 million, or even prosecution and a prison sentence of up to ten years.

An example of how seriously this scourge is being taken, is the expropriation of a piece of land without compensation, purely on the grounds of the landowner’s consistent lack of management with regard to invasive alien plants and the resulting significant fire hazard it posed to surrounding areas.

The Environmental Management Inspectorate (EMI), also known as the Green Scorpions, is becoming more active in policing transgressors because of the major risk invasive alien plants pose to the fragile South African agricultural economy.

The presence of invasive alien plants on private land is strictly controlled or illegal, and landowners could run the risk of being penalised if these plants are not controlled.

All is not lost

Despite the extent of invasion in some parts of South Africa, many landowners are making progress in the management of invasive alien plants. There are many stories of farmers successfully having removed invasive alien plants from fields, catchments and river valleys. In some cases they can see streams flowing again for the first time in 50 years or more.

The Working for Water programme of the Department of Environment, Forestry and Fisheries (DEFF) continues to clear tens of thousands of hectares of invasive alien plants, and this is increasingly being done in partnership with landowners and farmers’ associations. This collaboration is critical because government resources alone cannot overcome this challenge. It is also not their responsibility to do this alone; it is the landowner’s responsibility to manage invasive alien plants on private land.

Collaboration will win the day

Partnerships are key to successfully managing invasive alien plants. These partnerships require a combination of the government’s limited resources, the extensive clearing and rehabilitation skills of thousands of small, medium and micro-sized enterprises (SMMEs) that have experience in the clearing of invaders, the forestry sector, as well as landowners and farmers’ associations across the country.

The first step is to find ways in which the growth of invasive species can be tackled. Clearing a single piece of land is pointless as these plants cross farm boundaries. Large areas – ideally whole catchments – need to be cleared systematically and continually.

The DEFF-funded Clear to Grow programme, which is implemented by development agency Avocado Vision, builds and facilitates collaboration among role-players. It identifies and trains SMMEs in the sector to recognise opportunities for clearing invasive plants and helps to recover some of the cost of this process through the harvesting and sale of the biomass to viable markets.

Landowners should not always expect to recover the entire cost of clearing with money made from the sale of cleared biomass, such as firewood. Proper clearing and follow-up require hard work, and often the plants’ location and growth patterns make it hard to commercialise. However, across South Africa, new value chains turn the momentum in favour of cleared and rejuvenated agricultural areas, increased water resources and new economic opportunities.

Opportunities abound

Some of the main emerging value chains include:

  • An increasing recognition of mulching as a water-saving device.
  • Huge successes with composting based on the biomass of invasive plants.
  • Specialist soil augmentation products, such as customised compost and activated charcoal, as soil additives that significantly increase agricultural yields and build sustained quality of soil that is leached by over-fertilisation.
  • An innovative animal feed comprised at least in part of the cellulose of invasive plant species. Various ingredients, such as wattle leaves, mesquite and sekelbos, are used in different parts of the country. Even slangbos has potential as fodder augmentation.

Wood-based value chains also present opportunities. Logs and wood chips could be sold to local and international pulp and paper industries, while logs, chips, pellets and charcoal can produce energy when burned. Timber and wood composite materials can serve as biomass-based building materials.

Many of these value chains also offer commercial potential to farmers. However, the focus should be on the long-term benefits of recovering arable land and water resources and not on the profit made from biomass.

Call to action

The message to farmers across South Africa is to join the fight against the biggest threat to the agricultural sector after systemic climate change.

Know your rights and obligations. Find out how the presence of invasive alien plants on your land can pose ecological, economic and legal threats. Implement the necessary measures to remove invasive alien plants and return your land to productive economic use before you lose arable land and water resources forever.

Make sure the farmers’ or landowners’ associations to which you belong enter into partnerships with government and the private sector to implement and maintain clearing programmes at scale, as this challenge cannot be met in isolation.

Consider the potential of recovering at least some of the cost of the clearing from partnering with businesses who specialise in clearing, harvesting, follow-up work and rehabilitation of land. It could also be possible to link harvested biomass to new local and international biomass markets. – David Gardner, FarmBiz

For more information, send an email to the author at He is a
consultant to Avocado Vision.