ALIEN INVASIVE SPECIES
The amended regulations on alien and invasive species in South Africa…..
Do you have any alien invasive species in your garden?
The amended regulations on Alien and Invasive Species came into effect in October 2014. These regulations expand on the requirements of the Act and the broad aim is to prevent the introduction and spread of alien invasive species across South Africa. The Act covers all alien species but the current challenge for CCJ and the Environmental Committee is confined to alien invasive plants.
Invasive alien species occur everywhere and affect everyone, not only ecologically but economically too and, are not just plants, but include animals, insects and birds – the growth in numbers of the Indian house crow is a particular worry for example. Alien or exotic plants are plants brought into South Africa from other countries. Aliens that become serious problem plants are known as IAP’S (Invasive Alien Plants). Yes of course, not all weeds or problem plants are alien or exotic in origin but this is merely a criterion used to try and categorise a problem plant. IAP’s are the single biggest threat to plant and animal biodiversity as they impact on land such as nature reserves and valuable agricultural land.
Invasive species like Black wattles and certain Pine trees usually have deep root systems that allow them to access reserves of water found deeper in the soil, which the shallower indigenous grassland species cannot reach. These alien invasive species are highly adaptable, vigorous growers that quickly invade a range of habitats, ultimately threatening our indigenous species to the point of extinction if not properly managed. They compete for water, light, space and soil nutrients to the detriment of indigenous plants and often form dense stands killing all other plants around them. Indigenous species decline and so do the fauna that have evolved to depend on them.
South Africa has thousands of alien species, most of which are not necessarily a problem. A relatively small percentage have become invasive and the impact of these on the country’s economy is estimated in the hundreds of billions of Rands. Weeds have accidentally been introduced with crop seeds or have arrived in bales of cattle or horse feed. With crop cultivation, pests and weeds have flourished in new pristine habitats and subsequently spread to neighbouring environments. The impact of invasives on biological diversity, can be devastating. In a research study it was shown that the shading of water bodies by just one invasive alien plant, the Black wattle, could cause the extinction of more than half of the dragonfly and damselfly species that are only found in South Africa.
So a major focus of the Act and its Regulations is the early detection of and rapid response to emerging invasive species especially those requiring immediate control. A balanced approach is being sought for species that have value. Many of the invasive Gum species have a negative impact on water and, biological diversity, but they are also an excellent source of wood, shade, beauty, and above all food for bees. Provision has been made in the Regulations for optimizing their benefits, whilst curtailing the negative impacts.
The alien invasive and prohibited species have been listed in 4 categories:
Category 1a: High priority emerging species requiring compulsory control (eradication)
Invasive species that may not be owned, imported into South Africa, grown, moved, sold, given as a gift or dumped in a waterway. These species need to be controlled on your property.
e.g. Canary bush, Yellow flag iris
Category 1b: Widespread invasive species required to be controlled by a management program
Invasive species that may not be owned, imported into South Africa, grown, moved, sold, given as a gift or dumped in a waterway. Category 1b are major invaders and must be contained. In many cases they already fall under a government sponsored management program which assists with their removal.
e.g. Pompom weed, Pampas grass, Morning glory, Lantana, Common dodder, Black locust, Bugweed, Privet, Orange and yellow Cestrum, Honey locust, Australian silky oak, Cat’s claw creeper, Four o’clock, Oleander, Prickly pear, Blue pickerel weed, Red sesbania, Potato creeper, Wild verbena, Yellow bells (Tecoma), Silver wattle, Port Jackson Willow
Category 2: Invasive species controlled by area. Can be grown under permit in a demarcated area.
These are invasive species that have value such as plantation trees. They can remain, but only with a permit.
e.g. Jacaranda, White poplar, Black wattle, White mulberry, Weeping willow, Crack willow
Category 3: Ornamental and other species that are permitted on a property but may not be replanted.
There are invasive species that can remain. However, you cannot propagate or sell these species and must control them in your garden. Within watercourses or wetlands all Category 3 plants become category 1b plants.
e.g. New Zealand Christmas tree, Pepper tree, Spanish broom, Pink Tamarisk, Tipu tree (Tipuana), Canary Pine, Chinese maple, Box elder, Loquat, American ash, English ivy
CCJ’s Environmental Committee has, amongst other things, been charged with fulfilling the requirements of the Act and invasive plant removal is already underway on the Greater Woodmead Estate; in the past four years large stands of Gum trees and Black Wattle have been removed. Large beautiful and stately Gum trees will remain unless they detrimentally affect the golf courses. Removal of new alien invaders and creepers is ongoing.
Biological control, which the Environmental Committee began in November of 2014 along the left side of Rocklands 13 fairway, against the Pompom weed involves the use of natural enemies of the invasive alien species. This has become a critical component in the fight against unwanted weeds and pests, and it has been observed that to date South Africa has had exceptional success in the use of these agents.
And so to the much-loved Jacaranda tree and Pretoria’s pride and joy. Imported from Argentina in the 1880’s for ornamental purposes and through their sheer numbers they have become a South African icon. There is probably no flowering tree that evokes as much emotion in a South African as the sight of the Jacaranda trees in full bloom. While considered invasive in parts of the country, public sentiment has been considered by the Department of Environmental Affairs and in the latest Regulations no listing of the Jacaranda species in urban areas has been made effectively categorising them as plantations. This now means in urban areas there will be no control required for these trees. They can continue to be grown as street trees and ornamental garden trees. Here at Woodmead our very own avenues of Jacaranda trees now remain safe and beautiful and to be enjoyed by one and all in the months of October and November when there really is no mauve or purple to describe the Jacaranda flower colour other than to see it for oneself.
For further information see NEMBA (National Environmental Management Biodiversity Act) website. The laws governing the removal of the Jacaranda trees have been relaxed in certain provinces like Gauteng, KZN, Limpopo, Mpumalanga and North West but not others and as long as these trees are
located outside riparian areas.