Invasive Alien Plant/Bird/Animal Infestations

[Richprins]

[Richprins]

As the one says, the fences are in ruins.

[Lisbeth]

Learning from the river guardian who protects Plettenberg Bay’s source of water


Katot Meyer clears invasive alien trees and bushes. (Photo: Supplied)

For the past 50 years, Katot Meyer has been using his own makeshift tools to clear alien invasive plants from catchment areas to ensure a steady water supply for locals. Now he’s urging others to get involved as he cannot do it alone.
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A humble steward of nature, Katot Meyer at 77 years old is known as the river guardian in Plettenberg Bay. A cowboy of conservation, he has been using his own makeshift but effective tools for clearing invasive alien plants from the Keurbooms River catchment for the past 50 years – safeguarding the water that feeds households in the area.

Meyer works up and down the Keurbooms River catchment, which is approximately 80km long, clearing invasive alien trees and shrubs that reduce the flow of the water feeding households in Plettenberg Bay. He is also pioneering a water-neutral project in the area.

His efforts to rehabilitate the river are having a direct impact on the water supply, but the task is enormous and more involvement from the community, government and private businesses is crucial to safeguarding this water source.

Speaking to Daily Maverick, Meyer said it is critical for people to rethink how they can give back to the ecosystems that sustain them.

Meyer has spent the last 50 years using unique methods to clear high trees and thick bushes of invasive alien species along the tributaries that feed the Keurbooms River. By measuring the flow of water in the river, he has found that removing the alien species has increased river flow dramatically.

“In my lifetime, the flow of water in that specific area and in the Keurbooms, reduced from 100% in 1960 to about 25–30% now. We must reverse that green wheel, but to do that, we need funds and effective rehabilitation.

“The work that I do is a passion, and I have tried to do things very effectively because that’s the way we have to do [it] in future, because it’s mankind that caused all the problems in our catchments. It’s mankind without kindness. Now it’s that same mankind that must bring the solutions, and do it on the ground,” he said.

Daily battle


Katot Meyer measures water flow along the Keurbooms River. (Photo: Supplied)


The tractor Katot Meyer uses for clearing invasive alien species. (Photo: Supplied)

A typical day for Meyer starts with him entering a section of the catchment area either on his tractor or in his Land Rover, which he also sleeps in when necessary – with all his equipment attached on a trailer.

If he’s staying for two or three days to do a specific job in a section of the catchment, he’ll go in with a tractor and take his tent. Waking up early, he physically clears invasive alien species until about 11am, working with the tractor during the hottest part of the day. At about 3pm or 4pm, Meyer restarts physically clearing alien invasives until it’s dark.

“It’s nice, you rehabilitate the environment and you can see it. You look at what animals visit that area, and of course, the extra water coming from the catchment. But I can’t do it on my own,” Meyer told Daily Maverick.

Meyer said, however, that spraying herbicide to control alien invasive species is sometimes better as it costs roughly the same as using labourers, and using a drone can be more effective in reaching inaccessible areas.

Conservation while you work

Katot Meyer in the Pietersrivier Nature Reserve. (Photo: Eden to Addo Corridor Initiative)

Meyer said his focus is to be effective, because there is very little money in this sort of work, almost no time to do it and no labour. He uses what he calls a “while conservation method”, where you do conservation while you are there.

He explained that land users in the catchment area have at least one or two hours free while busy with their normal work – either going to the cattle or working in the veld.

To use that time effectively, Meyer said: “You have to have equipment on you, your bakkie or your trailer, spraying equipment, extra water, herbicide, chainsaw equipment.”

An example of Meyer’s cowboy equipment is a little chainsaw mounted with a herbicide spray gun. That means when he cuts an invasive alien tree, he is spraying it at the same time – “a hundred percent more effective operation”.

Meyer has also equipped the back of his tractor with a slasher (to cut wood). “Why don’t you put water, herbicide, slashers, chainsaws and everything that is used so that when you go into the catchment area, and meander through the work that you have to do, then you have all this equipment with you?”

One man can make a big difference, but if everyone can get on board, Meyer said they could make an even bigger difference.

“You must do it, every day; it’s a normal thing. It’s part of your normal work to do conservation because water is the main thing. We are going to run out of water.”

Meyer has pioneered the Keurbooms River Conservation Corridor, which links two of the bigger protected areas of the Garden Route National Park and is a critical watershed for Plettenberg Bay and the Greater Bitou Municipality. This forms part of the Eden to Addo Corridor Initiative to establish a protected environment.

“If you turn the tap on in Plett, you must think about where the water comes from? How can I support the catchment?” he said.

Much still to be done

Rehabilitating a catchment in South Africa today is not easy, Meyer said, and much remains to be done in the two catchments where he works: the Keurbooms River and Kammanassie River catchments.

In the past six years, drought has hit both the Keurbooms and the Kammanassie catchments. In the Keurbooms, there was just enough water to feed the estuary and the people, Meyer said.

In the Kammanassie, “there was a real disaster”, and all those who rely on the river came together to see if they could rehabilitate it.

“If you are in the Keurbooms, where do we get the money from? There’s no farming or very expensive export – as with the ostrich skin for leather in the Karoo – but if you look at the culprits in the Keurbooms, it’s actually the land users and they can’t come out with any money now,” he said.

Meyer is trying to rehabilitate the catchment by farming with water – making new water that would have been sopped up by invasive alien trees and bushes.

A water-neutral project

Katot Meyer at the Pietersrivier Nature Reserve. (Photo: Eden to Addo Corridor Initiative)

Meyer runs a water-neutral project in Pietersrivier Nature Reserve, where if one hectare of 100% canopy of invasive alien plants is rehabilitated, an average of 2,400 cubic metres of water per hectare per year will be secured.

“When the exotic trees are in a river; it’s three times that. What I got out of this project, the very interesting thing is it’s about 40 hectares of really packed wattle in a bigger area of 240 hectares of fynbos. There’s about three little rivulets and we cleared 30 metres wide – that’s a bit of money for Conservation at Work, an NGO,” he said.

Pietersrivier is a small tributary of the Keurbooms, roughly in the middle of the catchment, 50km upstream from Plett, so the water in the grid goes down to the small households there.

For three-quarters of a day, Meyer and a group of elderly women, “old aunties over 70”, managed to rehabilitate 75% of a one-hectare stand of about 50% wattle.

“A very interesting thing to think about is that companies on the coast, even individual water users, can become water neutral – where the amount of water that you use, you can get back from the catchment. That means, if they use a certain amount of water over a year, and we calculate that they can fund an area that we clear to match that amount of water,” Meyer said. DM

The Eden to Addo initiative has appealed to all those interested in becoming a river guardian like Katot and contributing to alien clearing strategies in the Keurbooms catchment, to get in touch with the Plett Environmental Forum on info@plettenvironmentalforum.co.za.

[Lisbeth]

PANZOOTIC PERIL

Half the world’s breeding population of wandering albatrosses at risk after suspected deadly bird flu hits Marion Island


A wandering albatross soaring low over the Southern Ocean. (Photo: Tiara Walters)

By Tiara Walters, 12 Nov 2024

Possible infiltration targets globally significant seabird colonies, including wandering albatrosses.
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Highly pathogenic avian flu is suspected to have reached Marion Island, South Africa’s sub-Antarctic territory in the southern Indian Ocean which supports about half the world’s breeding wandering albatrosses.

According to a statement from South Africa’s Department of Forestry, Fisheries and the Environment, the H5N1 virus “is possibly responsible for causing mortalities in at least three breeding seabird species”.

“After an initial suspected case in a brown skua in mid-September 2024, another five suspected cases were found in early November 2024, involving three wandering albatross chicks and two southern giant petrel adults,” the department notes. “The virus can be transported long distances by migrating birds, and this is likely how the virus arrived on Marion Island.”

The spread of H5N1 to the Antarctic and sub-Antarctic has introduced a serious threat, as first confirmed by the British Antarctic Survey in October 2023, which found the virus in brown skua birds on South Georgia, a UK sub-Antarctic territory.

These skuas likely contracted the virus in South America, where H5N1 rapidly advanced since its arrival in 2022, causing mass mortality among birds and marine mammals over a 6,000km stretch to the tip of the continent.

In Antarctica, the virus now endangers over 100 million breeding birds and numerous mammal species, including six types of seals and 17 cetacean species.

“The Prince Edward Islands, comprising Marion Island and Prince Edward Island, are breeding and moulting sites for millions of seabirds, including almost half of the world’s wandering albatrosses and hundreds of thousands of penguins,” the department says. The islands also host “large numbers of southern elephant seals and sub-Antarctic and Antarctic fur seals”.

The department says the situation is “being closely monitored by 11 field personnel overwintering on the island, who have been trained to recognise possible highly pathogenic avian flu signs in birds and seals, and in the necessary monitoring and mitigation methods”.

They are taking “all precautions” to prevent the spread of the virus and gathering information to help guide decisions on the appropriate response, the department adds.

In April, Daily Maverick’s international investigation revealed that biosecurity coordination and surveillance efforts among Antarctic Treaty states had been fragmented.

While some countries, such as Chile and the UK, had shared their biosecurity protocols, there had been no unified approach to surveillance and response.

Scientists had warned that climate change could exacerbate the spread of the virus, but the Antarctic Treaty system’s secrecy, media restrictions and delayed communication raised questions about its approach to managing global environmental and health crises.

At the time, Pretoria University’s Professor Nico de Bruyn noted Marion Island’s researchers had taken their own initiative to introduce biosecurity in the absence of government protocols. South Africa said it was planning to table its protocol at the India-hosted Antarctic Treaty consultative meeting in May.

In its statement issued on Tuesday afternoon, the department was at pains to point out that it had now developed a protocol for managing highly pathogenic avian flu in seabirds.

It had worked with Western Cape Veterinary Services, marine ornithologists, marine mammal biologists, disease experts and “colleagues overseas with similar experience, and will continue to work to monitor and hopefully limit the spread of the virus on the island”.

The statement does not mention any potential impacts on seals.

However, Pretoria University’s Professor Marthan Bester, a leading polar mammal authority, feared a grim outcome might face the sub-Antarctic territory’s elephant seals. If the virus hit, “bitterly few” would survive, he told Daily Maverick.

“I think we are all collectively struggling with ecological grief and are speaking as loudly as we can,” said Dr Michelle Wille of the Antarctic Wildlife Health Network, an initiative of the Scientific Committee on Antarctic Research. “It has been very challenging to convey the level of mortality to the public, as well as the implications of these mortality events. Scientists are speaking widely to media outlets as best as possible.” DM

[Lisbeth]

South Africa’s famous fynbos must be preserved – but burning invasive plants on site isn’t the best strategy

February 24, 2025 | Mlungele M. Nsikani | Senior scientist, South African National Biodiversity Institute


Clearing invasive plants like pine trees in South Africa. Samantha Reinders/The Washington Post/Getty Images

Invasive plants and trees were introduced to South Africa from as early as the 17th century for a range of commercial, subsistence and ornamental uses. Today, every area of the country has been invaded by a variety of these plants. The most species are found in the Western Cape, Eastern Cape and KwaZulu-Natal provinces, and major urban centres.

Invasive plants such as port jackson, black wattle and gum trees threaten the country’s water security by using up too much water. They also fuel fires by adding biomass into the ecosystem, particularly those ecosystems where trees would not naturally grow. Invasive plants (including trees) can also degrade pasture lands by converting them into woodlands, full of plants that grazing animals do not eat.

Read more: Nearly 25% of land in Africa has been damaged – what's to blame, and what can be done

As a consequence, concerted efforts have been made in projects run by government and nature organisations to clear these plants and replace them with indigenous vegetation. Clearing invasive plants can be done through various methods such as herbicide spraying or chopping them down.

In South Africa’s Western Cape, a common feature of clearing efforts is the “stack burning” method. This is where invasive plants such as port jackson are chopped down, stacked on top of each other and allowed to dry out before being burnt.


Fynbos takes longer to regenerate on burnt land. Martin Harvey/Getty Images

Clearing efforts are focused on the Western Cape’s fynbos ecosystem. The fynbos is the country’s most invaded ecosystem and most of the research on invasive plants has taken place in this ecosystem. Despite the large extent of invasive plants in the fynbos, the ecosystem has exceptional biodiversity, containing a high number of endemic species found nowhere else on Earth.

But stack burning has its downsides because it leaves burn scars on the land.


The author in the fynbos. Courtesy SANBI

I’m a land restoration specialist and environmental scientist who set out to research how stack burning affected the ability of fynbos to regenerate naturally. I visited 80 stack burn scars in two different fynbos ecosystem types in the Western Cape. I revisited the burnt sites every year for three years after the invasive plants had been removed and their biomass burnt away.

My research found that full recovery of stack burn scars remains limited up to three years after clearing. One of the key research findings was that fynbos had not grown back fully even three years after the burning took place. Furthermore, the two fynbos ecosystem types recover differently.

To reduce the effects of stack burning, wherever possible, other clearing methods should be used. This could include removing the biomass without burning or burning the biomass on existing roads within the site.

Tracking the impact


Measuring fynbos regrowth. Courtesy SANBI

I studied two types of fynbos ecosystems in the Western Cape: mountain fynbos and lowland fynbos. These are some of the ecosystems with the highest density of invasive plants in the country.

I set up observation areas at the centre and edge of each burn scar and outside it. These measured one square metre each. For three years after burning, I counted the number of species that were found each year in the centre and at the edge of each burn scar.

Read more: Invasive alien plants in South Africa pose huge risks, but they can be stopped

I then compared the burnt area with plots outside the burn scar where no fire had occurred.

The heat of the fire at the centre of the stack reaches over 300°C. At the edge, temperatures reach 175°C. This often leaves persistent stack burn scars on the land. Stack burn scars are areas that have been left charred and stripped of vegetation by the intense fires during stack burning.

Stack burning leaves scars on the earth

Stack burning has negative effects on the environment. These include:

• persistent scars that are an eyesore across the landscape

• limited native biodiversity recovery in burnt areas (as shown by my research) because the vegetation takes so long to grow back

• secondary invasion – where other invasive plants that were previously not present find space to germinate and grow

• changes to the soil chemical, physical and microbial conditions. For example, stack burning can wipe out microbes that are crucial for the success of native plants.

My research found that areas at the centre of the stack remain severely affected and do not fully recover even three years after the stack burn. Areas at the edge of the stack recover within two years.


Fynbos cannot regenerate naturally on burn scars. Martin Harvey/Getty Images

This shows that cutting down invasive plants and burning them on site prevents those areas from recovering naturally on their own. They will need help from humans to regrow.

Another important finding was that the two fynbos ecosystem types recover differently. Lowland fynbos recovers faster than mountain fynbos. Restoration specialists need to develop restoration plans that are tailored to the specific ecosystem.

What needs to happen next

To reduce the effects of stack burning, wherever possible, other clearing methods should be used. For example, invasive plants can be cut down and removed. They do not need to be burnt on site. Alternatively, the biomass can be removed and burnt on mountain roads, where the fires won’t damage natural fynbos.

Where stack burning is unavoidable, there may be a need to apply fynbos seeds to stack burn scars to improve native species recovery. Stack burn scars could also be covered with surrounding topsoil to encourage recovery of native soil seed banks and microbial communities. However, this is labour intensive, so it would probably only be feasible at small scales.