Sandspruit News

Alien invasives

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02 September 2016
(updated 10 October 2016)

Alien Invasives

The Sandspruit has, over many years, become overgrown with many alien and extremely invasive shrubs, climbers and trees.

It is never popular to remove established trees, but for the long-term maintenance of the waterway in particular it is necessary to do so.

Why is it necessary?

Its the law!

NEMBA, the “National Environmental Management: Biodiversity Act (No. 10 of 2004)” provides the framework, norms, and standards for the conservation, sustainable use and equitable benefit-sharing of South Africa‚Äôs biological resources.


Honey locust

On 1 August 2014, the Invasive Species Regulations were published in the Government Gazette and became law on 1 October 2014.

According to the regulations, all Category 1a and Category 1b plants must be eradicated from our park, but in addition to this, all Category 2 and Category 3 plants in riparian zones or wetlands become Category 1b plants and must be eradicated. Riperian zone refers to an area within 32 metres of the edge of a river, lake, dam, wetland or estuary, or within the 1:100 year floodline, whichever is the greater.


Ink Berry

Bank erosion

If you wander down the river where we have cleared heavily overgrown areas of Black Wattles, Common Mulberries, Weeping Willows, Crack Willows, Black Locusts and Honey Locusts you will see bare patches of earth with no grasses able to grow in the dense shade. There are often serious signs of erosion in these areas.

Look further down where the grass is able to grow in the light and you will see that there is little or no erosion. We need the grass to regrow in these areas to protect the banks from further erosion. Sometimes we have been able to simply trim the trees up to allow more light in and therefore in the short term we have left many of the alien trees, but longer term these will be removed once our newly planted trees have had time to establish.


Sandspruit in flood

Out-competing the locals

Where alien trees like mulberries and black locust trees are left to there own devices, they form dense thickets and out-compete the indigenous flora. Black Locust colonies are so rampant that they are causing many problems around South African waterways where they are preventing animals getting to water.

When we clear our area of these troublesome aliens, bare in mind that we are preventing thousands of seeds travelling down river where they could cause major problems in areas that aren't being tended to. Projects like ours must be viewed on a wider scale to really appreciate how a little done here can make a difference all along our water courses.

If we move away from the river and up towards Ullmann Park, we can again see the problem with leaving a few Common Mulberries to get out of control. Where there were three large mulberries near the entrance to the Park from Minto Road, we have lost at least seven large aloes - Mountain Aloes (Aloe marlothii) and Bitter Aloes (Aloe ferox) - because they were being completely shaded by the Mulberries. They have also out-competed the local Searsia lancea (Karee) which has lost an entire side due to one large mulberry (this particular mulberry was cut down last week and has flooded the area with light. We are in the process of rehabilitating the area now).

Which plants are our biggest problem?

At the time this article was written, there were 381 invasive alien plants listed by NEMBA (National Environmental Management: Biodiversity Act). Many of them have little or no impact on our area, however the few that are causing problems have been allowed to grow rampantly over many years. Below is a list of the most important invasive plants that we will striving to eradicate over the next few years.

Balloon Vine (Cardiospermum grandiflorum)

Balloon Vine (Cardiospermum grandiflorum)

Category 1b
Belhambra (Phytolacca dioica)

Belhambra (Phytolacca dioica)

Category 3
Black Locust (Robinia pseudoacacia)

Black Locust (Robinia pseudoacacia)

Category 1b
Black Wattle (Acacia mearnsii)

Black Wattle (Acacia mearnsii)

Category 2
Bugweed (Solanum mauritianum)

Bugweed (Solanum mauritianum)

Category 1b
Castor-oil Plant (Ricinus communis)

Castor-oil Plant (Ricinus communis)

Category 2
Cat's Claw Creeper (Dolichandra unguis-cati)

Cat's Claw Creeper (Dolichandra unguis-cati)

Category 1b
Chandelier Plant (Bryophyllum delagoense)

Chandelier Plant (Bryophyllum delagoense)

Category 1b
Chilean Cestrum (Cestrum parqui)

Chilean Cestrum (Cestrum parqui)

Category 1b
Chinese Wax-leaved Privet (Ligustrum lucidum)

Chinese Wax-leaved Privet (Ligustrum lucidum)

Category 1b
Common Morning Glory (Ipomoea purpurea)

Common Morning Glory (Ipomoea purpurea)

Category 1b
Common Mulberry (Morus alba)

Common Mulberry (Morus alba)

Category 3
Common Thorn Apple (Datura stramonium)

Common Thorn Apple (Datura stramonium)

Category 1b
Crack Willow (Salix fragilis)

Crack Willow (Salix fragilis)

Category 2
Downy Thorn Apple (Datura innoxia)

Downy Thorn Apple (Datura innoxia)

Category 1b
Field Bindweed (Convolvulus arvensis)

Field Bindweed (Convolvulus arvensis)

Category 1b
Four o’ Clock (Mirabilis jalapa)

Four o’ Clock (Mirabilis jalapa)

Category 1b
Giant Reed (Arundo donax)

Giant Reed (Arundo donax)

Category 1b
Honey Locust (Gleditsia triacanthos)

Honey Locust (Gleditsia triacanthos)

Category 1b
Indian Shot (Canna indica)

Indian Shot (Canna indica)

Category 1b
Inkberry (Cestrum laevigatum)

Inkberry (Cestrum laevigatum)

Category 1b
Jerusalem Cherry (Solanum pseudocapsium)

Jerusalem Cherry (Solanum pseudocapsium)

Category 1b
Lantana (Lantana camara)

Lantana (Lantana camara)

Category 1b
Large Thorn Apple (Datura ferox)

Large Thorn Apple (Datura ferox)

Category 1b
Morning Glory (Ipomoea indica)

Morning Glory (Ipomoea indica)

Category 1b
Moth Catcher (Araujia serifera)

Moth Catcher (Araujia serifera)

Category 1b
Pampas Grass (Cortaderia selloana)

Pampas Grass (Cortaderia selloana)

Category 1b
Purple Pampas Grass (Cortaderia jubata)

Purple Pampas Grass (Cortaderia jubata)

Category 1b
Red River Gum (Eucalyptus camaldulensis)

Red River Gum (Eucalyptus camaldulensis)

Category 1b
Syringa (Melia azedarach)

Syringa (Melia azedarach)

Category 1b
Tipu Tree (Tipuana tipu)

Tipu Tree (Tipuana tipu)

Category 3
Weeping Bottlebrush (Callistemon viminalis)

Weeping Bottlebrush (Callistemon viminalis)

Category 3
Weeping Willow (Salix babylonica)

Weeping Willow (Salix babylonica)

Category 2
White-flowered Mexican Poppy (Argemone ochroleuca subsp. ochroleuca)

White-flowered Mexican Poppy (Argemone ochroleuca subsp. ochroleuca)

Category 1b
White Poplar (Populus alba)

White Poplar (Populus alba)

Category 2
Yellow Bells (Tecoma stans)

Yellow Bells (Tecoma stans)

Category 1b
Yellow-flowered Mexican Poppy (Argemone mexicana)

Yellow-flowered Mexican Poppy (Argemone mexicana)

Category 1b
Yellow Oleander (Thevetia peruviana)

Yellow Oleander (Thevetia peruviana)

Category 1b

What do the NEMBA categories mean?


Category 1a

Invasive species requiring compulsory control. Remove and destroy. Any specimens of Category 1a listed species need, by law, to be eradicated from the environment. No permits will be issued.


Category 2

Invasive species regulated by area. A demarcation permit is required to import, possess, grow, breed, move, sell, buy or accept as a gift any plants listed as Category 2 plants. In riparian zones or wetlands all Category 2 plants become Category 1b plants.


Category 1b

Invasive species requiring compulsory control as part of an invasive species control programme. Remove and destroy. These plants are deemed to have such a high invasive potential that infestations can qualify to be placed under a government sponsored invasive species management programme. No permits will be issued.


Category 3

These are invasive species that can remain in your garden. An individual plant permit involving a Category 3 species is required to undertake any of the following restricted activities: import, possess, grow, breed, move, sell, buy or accept as a gift. In riparian zones or wetlands all Category 3 plants become Category 1b plants.



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