Alien plant invasions

[Naturesguy]

Hi to all, are you guys aware that there are currently
367 alien invader plant species in the park? Two of the worst one's are Lantana camara which covers some 30,000 ha, and
Opuntia stricta (sour prickly pear) covers about 35,000 ha
in the Skukuza region. Alien invaders rate as the single biggest
threat to the biodiversity of the park, quite scary! I believe that all nature lovers need to become aware of the invaders, not only in the park, but at home as well, and to educate family and friends to control them.

[Jakkalsbessie]

From KPT Vol 2 Issue 19

The Kruger National Park's programme manager for invasion ecology, Llewellyn Foxcroft, recently journeyed to Poland to take part in an international conference on the ecology and management of alien plant invasions.

Currently writing up his presentation on Kruger's experiences for the conference proceedings book, Foxcroft says that the international delegates from 31 countries were positive about South Africa's Working for Water programme.

"It is regarded widely as a model approach." At the conference Foxcroft presented Kruger's challenges and lessons learnt in dealing with the problem of invasive plants, and how the park's adaptive management strategy copes with the ongoing problem.
One challenge facing the park is the integration of the Working for Water (WfW) programme with the park's own alien plant task force, headed up by Vusi ngomezulu.

Foxcroft says that as WfW is so large, its planning is done up to a year in advance.
This poses a problem when an alien springs up suddenly in the park, as was the case with the water weed Azolla. This appeared in Kruger's rivers in a matter of months, and is now being controlled by a biological pest.

Foxcroft explains, “It is difficult to work a new weed into the programme," but adds that once WfW has educated all the teams and their leaders about new aliens, the programme puts a plan into action to combat it.

The park now has a two-pronged approach, in that its small task force will deal with any new pests that crop up in a localised area, calling in WfW if the infestation gets out of hand.
Kruger's team does not only deal with aliens inside the park's boundaries, but searches out and deals with aliens that grow outside the park in places like Hazyview. These can readily spread into Kruger.

New research is also underway in Kruger to look into the exact impacts that alien plants can have on other organisms, such as beetles and spiders. A masters student will be looking at the differences between invaded and non-invaded areas.

This will lead in to Kruger's environmental monitoring, by finding out precisely which indicators are most sensitive to alien invasions. Although Foxcroft would like to see more awareness of the alien plant issue and a growing recognition of problem species, he believes that the continued awareness programme is finally bringing the problem to public prominence.

[Jakkalsbessie]

Why is it called the Working for Water programme?

As the name implies, the Working for Water Programme helps to reverse what will otherwise be a devastating trend in terms of water security - not only the obvious aspect of water supply, but water quality issues and associated problems such as turbidity, thermal problems, erosion, siltation of dams and flooding.
Alien species wreak havoc on our world, chomping our natural resources and destroying our biodiversity. To chop down and clear invading alien species, including Wattle, Gums, Pines, Hakea, Triffid Weed - the list goes on.
Many of these invasive species consume vast quantities of water, thus depleting our precious supplies.
They also fuel devastating fires, which can destroy our indigenous species, and cause millions of rands in damage.

Invasive alien plants also have a severe impact in terms of other concerns, including biological diversity and the ecological integrity of natural systems, fire management, the productive use of land, and ultimately the conservation of our life-support systems.

[Imberbe]

We were allowed to plant any plants in our gardens. This became problematic because of the rapid spread of alien plants. Recently a new system has been implemented by government restricting the planting and keeping of certain plants. It works in a three tiered approach:

Category 1 plants: Plants which is totally banned. They may not be planted and must be destroyd where they occur. E.g. Lantana camara, Cats Claw Creeper.

Category 2 plants: Plants that may be planted for commercial reasons in demarcated and controlled areas only. May not be planted in other areas and must be destroyd where they so occur. E.g. Green wattle, some pine tree species

Category 3 plants: Plants that may not be planted and propagated further. They may be kept where they already occur, except if they occur in sensitive area such as near streams etc. E.g. Jacaranda, Morning glory

[Macrotis lagotis]

Hi,

I find it interesting to hear about the trouble Australian natives such as wattles and eucayltps are causing over in South Africa, as many of our major weed problems such as african boxthorn and bridal creeper came to Australia on ships that stopped over there on the way.

Its not original but truely a weed is a plant out of place.

[gavinl]

Now over December I noticed on the road between Lower Sabie and Skukuza a patch were branches had been cut of the thorn trees ( took photos). Asked the ranger on the night drive and his explanation were " possibly to clear the road" but I could see he did not believe this. Also, the branches that was cut were no where to be seen - I thought it was policy that if they were cut these branches were to be left in the veld. Any comments or explanation on this..

[niknak]

Working for Water seem to have a program clearing unnatural growth next to the tar roads. Runoff rainwater tends to produce unnatural growth in these areas. I have seen this done on the H1-2.

[Freda]

Was this perhaps Sickle Bush, I asked the same question and was told it was alien and invasive
I hope not as I love those lantern like flowers.

[bucky]

Sickle bush is indigenous to parts of Southern Africa.
It only invades areas that are overgrazed and open, and is considered invasive by farmers as it will grow easily on ploughed open fields .
I suppose one could consider it a pioneer tree as it establishes quickly on hostile open ground, and then allows slower growing trees to establish themselves later on.

They do clear and remove some vegetation along the roads as niknak says , because of extra growth due to road runoff .

Can you post a picture of the tree ?

[niknak]

In areas where the added nutrients and water runoff from the tar roads promotes growth that is not natural to the area and that creates a barrier to game viewing “Working for Water” appear to be cutting the growth back a couple of meters from the edge of the roads. I have seen evidence of this on a number of roads over the past four or five years. Often the bush and trees are cut back to a few inches of the ground and then the stumps painted with a substance that has different colors. These stumps are visible for a while until the grasses in these areas grow.

[KNP Spokesman]

Hi Forum Folks

You've pretty much summed it up here folks. Unfortunately I got the red crosses instead of the photographs so I can't say for certain in this particular instance what trees they were, but our Working 4 Water teams do take out trees where rain run-off has made what we call a bush curtain.

One of the most obvious examples of this bush curtain can be seen on the road between Letaba and Mopani camps, where the Mopani trees on the sides of the road are probably double the size of the rest of the trees. As this is unnatural, we have a system in place where every 2nd/3rd/4th tree is removed (depending on intensity of growth).

Remember that these trees will soak up more moisture than normal, thus not letting moisture get to the other vegetation behind them, thus creating infinite problems with erosion (and so it snowballs).

There are obvious other benefits to controlling this "bushcurtain", most notably the benefits of being able to see better from the road, but I can assure you the primary reason for removing those trees is so that we can make those areas more natural (in spite of the impact of the "man-made" road).

The colours that you see painted on the stumps are to prevent the tree growing again.

Hope that explains.

Kind regards
KNP Spokesman

[Elsa]

Thanks KNP Spokesman,
also noticed a lot of this cutting of branches back on the H11, Skukuza/Kruger gate road this last week.
Must say it does look a bit strange when first seen.

[Carol g]

A few years ago when visiting Kruger we were on our way to shing and saw Sanparks workers chopping and removing plants and bushes next to the road and in the bush, we stopped and asked what they were doing and they said they were removing invasive plants. This was on the road between Mopani and Shing.

[saraf]

There are some cactus like species in Addo I believe, DB might be able to tell you more as I think she did some clearing of them.

Orpen Dam in Kruger has an invasive species on the water. There's a notice about it and how they are tackling it. Which I think is more along the lines on containment rather than eradication.

And of course there is the hugely controversial removal of the eucalyptus forests in Table Mountain NP.

[lizef]

This article might prove useful in providing some info regarding alien species management in South African National Parks:
http://www.koedoe.co.za/index.php/koedoe/article/view/1032/1290
I will try to source some additional info on the wonderful work done via the various projects in our Expanded Public Works Programme.