IMPACTS OF INVADING ALIEN WEED IN OUR RIVERS

Indigenous verse Alien An Indigenous plant refers to a plant which naturally grows in an area/country

An Alien Plant is a plant from another country that has been brought over intentionally or unintentionally by man or animal

An endemic plant is not only indigenous but also restricted to a particular area.

WHAT ARE INVADING ALIEN WEED A great deal of South Africa's water is used by plants that do not belong in this country. They are called " Alien" plants. Some of these alien plants are invasive because they spread fast and displace our natural trees and plants. Some of these plants like Wattle and Bug Weed have invaded large areas of good agricultural land and some of our most scenic, touristy areas

There are 2000 alien plants in South Africa but only 10% are invasive Water Lettuce covers the surface of a river preventing O2 and sunlight Balloon Vine Taking over a Forest

Invasive Alien Plant can take over and disrupt a whole Eco-System

WHY DO INVADING ALIEN WEEDS GROW SO WELL? In South Africa these plants have no natural enemies such as insects, animals and diseases that would have controlled them in their own countries. These plants out compete Indigenous Plants for sunlight, space, water and nutrients

WHERE DO INVADER ALIEN WEED COME FROM? The Pickly Pear, from Mexico, was introduced to South Africa as a fruit for human and animal food. The spiky, fast growing plant was used a hedge/fence to control the movement of animals.

The Australian Wattle Tree was fasting growing providing timber for building houses and the tannins were used for curing leather.

Lantana, for example was used as a pretty ornamental plant to beautify the garden.

Some plants like Maize have been in South Africa for hundreds of years and have been included in Africa Culture.

Other common Alien Invasive plants found in South Africa. Bugweed/ uBhongabhonga( Solunam mauritianum) originally from S.America.

Castor Oil / uMhlakuva A Pioneer plants that invades highly disturbed area’s Highly poisonous to Animals

Peanut Butter Cassia Widely distributed in Grasslands and river banks in KZN Seed are poisonous

REASONS WHY ALIEN INVADERS ARE A PROBLEM Use a lot of water Invading alien plants, particularly deep rooted, evergreen trees use much more water than indigenous trees and plants. These plants dry up rivers and water underground

HOW MUCH WATER IS CONSUMED

They cause devastating fires When invading alien trees burn, the flames can be up to 15 m high, often destroying houses and damaging the soil. Invading alien plants grow in denser stands than natural shrub preventing fire fighters from putting out a fire. Chromolaena/ uHalahala plants are highly flammable allowing fires to penetrate deep into forests

They cause soil erosion Fires in invading alien vegetation are more hot than those in natural vegetation, resulting in damage to the soil. With the first rains the soil is then washed into rivers causing the rivers and dams to fill up with sand

How do we control Alien Invasive Plants? Mechanical Control Methods Physically removing the plant by hand or tools ( machines and instruments)

Chemical Control Using herbicides that kill the Alien Invasive Plant without killing the other plants

Biological Control Introducing the plants natural pest and predators The Chromolaena Leaf-eating Moth

They displace indigenous plants Large areas of our country have been infested with invading alien plants. They destroy precious vegetation such as fynbos in the Western Cape and destroy the habitats and food sources for our Indigenous animal

HOW CAN YOU HELP SOLVE THE PROBLEM Look for invading alien trees and plants in your area and cut them down. Ask your neighbours to do the same.

Plant indigenous trees and plants instead

HOW DO WE BENEFIT By clearing invading alien vegetation we improve water supplies. It will not be necessary to build so many dams; this will save money. We protect our local plants and trees. We help to prevent fires and erosion.

END THANK YOU