The phrase "alien clearance" might invoke images of the 1970s space invader game, but in South Africa it is a vital part of any conservation effort. As with many other parts of the world, South Africa has its fair share of plants, "aliens", that have been introduced to the country for one reason or another, yet have escaped their original purpose and "invaded" the natural vegetation. Unfortunately, Phillipskop is not immune from these alien invaders and so to maintain the natural vegetation we have to carry out a continuing programme of alien clearance.
Large stand of Port Jackson and cleared area in front
The area around our self-catering chalets has now been cleared of alien Port Jackson
Not all alien plants become invaders but those that do can quickly come to dominate the vegetation as the environment that they invade does not contain any of their native diseases or predators. As they come to dominate the vegetation, they squeeze out the native plants through their shade, taking up spare water or by changing the environment. This can change a naturally diverse habitat into one where a single species dominates. At Phillipskop, one such problem plant is commonly known as Port Jackson, an Australian species of wattle, Acacia saligna.
Port Jackson grows on the lower slopes particularly around streams. It can easily become so dense that no other plants can survive amongst it. It is vital that we not only stop the Port Jackson from spreading further but, if we can, return those areas that it has already invaded to the natural fynbos that was there before. The problem with Port Jackson is that it is not just a question of cutting it down, for it quickly resprouts from the stump. It is necessary, as much as we would prefer not to, to use specialised herbicides on the stumps that are taken down into the roots and kill the whole plant. However, even this may not be sufficient and it is important to return year on year to the area to remove any plants that have survived and pull out any seedlings that have appeared in the meantime.
Cleared patch of Port Jackson, showing stumps painted blue with herbicide. Note the lack of any other plants that have managed to survive under the dense growth. We hope that this will recover back to fynbos over the coming years.
Alien clearance team
As you can tell from this, it is a lot of work. We have been fortunate to receive assistance from a neighbouring farmer, Peter, who has been diligently working on removing the aliens from his own fynbos reserve. He sent a team over for a couple of weeks and they have transformed the area directly beneath the self-catering chalets. There is still plenty of work to be done, as well as the follow up, but it is a great start for now.