animals that are from a different geographical location. They threaten the endemic species of an area by taking over the natural resources, driving the endemic species to the brink of extinction. They cause an imbalance to the ecosystem and biodiversity. Invasive species are easy to eradicate when their population is small. It is when the population grows huge and becomes widespread; it becomes difficult and costly to eradicate them.
Some of the methods used to control the spread of invasive species are as follows:
The most economical and safest way to manage invasive species is by prevention. The early detection and eradication of invasive species is much more effective than trying to control a widespread infestation. It is important that new species are not introduced into a sensitive area. Most often, equipment and vehicles carry the invasive species into a new area. Livestock and wildlife can also be responsible for the spread of invasive species into other areas. Thus, the way to prevent the spread of invasive species is to ensure all vehicles and equipment are clean, and livestock are immunized and kept separate from new livestock. Only when the new livestock have been checked for diseases and parasites and immunized, they can be allowed to mingle with the other livestock¹,².
- Manual control
Manual control involves physical control methods such as hand-pulling (weeding) or digging. This method works well for small populations of invasive plant species in an area¹,³. This management method has to be consistent and thorough in order to prevent the infestation from getting out of hand. This method is time and energy consuming, but very effective in terms of eradication at a smaller scale.
- Chemical control
Various pesticides can be applied to some invasive species that are persistent. Usually used in widespread infestations, this method is applied in varying degrees. However, the use of method is discouraged in areas near water and other sensitive areas¹. The use of this method is highly debated as this method can cause adverse impacts on the biota, and may eradicate non-target and sensitive species as well, which can lead to species extinction.
Often after removal of the invasive species, there are no methods of preventing them from repopulating an area. In agriculture, after removing the invasive species from a plot of land, it is recommended to re-vegetate the plot with crops or non-invasive ground cover plants¹. This will prevent the invasive species from repopulating the area due to the competition existing at the area.
- Biological control
Many invasive species come from other geographical areas without their natural enemies or diseases that affect them. In a new area, they thrive with no external factors keeping them in check. This method often works on large infestations or infestations near water. This method is beneficial and environmentally friendly as it uses the natural predators of an organism to keep it in check. This method also prevents non-target and sensitive species from being killed. Biological control method is the cheapest and is a long-term solution. Although biological control does not fully eradicate the invasive species, the population is controlled. This method takes time to implement but is very effective¹,².