What are invasive alien species?

INVASIVE species have been a major cause of many environmental problems in most countries in the world today. Invasive species are defined as organisms which can either be a plant, animal, fungus, or bacterium that are not native or indigenous and have negative effects on the environment.

To be invasive, a species must adapt to the new area easily and have competitive advantage over other species. A good example of an invasive species causing much harm in Zimbabwe is Eichhornia crassipes (Water hyacinth) which is native to the Amazon basin.

This plant has invaded the country’s invasive plants grow in new habitats where they never existed before and thrive in those areas because of absence of predators or natural enemies in the new location.

Another reason why many invasive species thrive is because they out compete native species for food and have a high fecundity rate compared to most native species. Not all introduced species are invasive because not all on them have a negative effect on the ecosystem.

Effects Many invasive plants are responsible for the following

Habitat damage Loss of subsistence resources Economic loss. Damage infrastructure Obstruct water transportation or decrease water availability by blocking waterways

Environmental concerns

The invasive alien species threaten biodiversity by displacing native plants and animals. This will result in shift of the ecosystem that will affect the food availability, for some animals that feed on the native plants replaced by the invasive species. In severe cases this might lead to extinction of other species. Some of the invasive species are aquatic and they are invaders that harm native species by bringing disease and altering ecosystems. Any change in the ecosystem will result on impacts of fisheries, tourism, health and recreation.

What we can do to reduce invasive alien species

◆ Avoid movement of water organisms like fish or plants from one water body to another Check and remove mud, weeds and aquatic life from equipment before leaving the area because mud and weeds can keep invasive species cool and moist, allowing them to reproduce faster Drain water from bilges, pumps, coolers and buckets before leaving the area because if water is removed it will be hard for the invasive species to survive Clean boat and gear and should be dried by the hot sun for some days before use in another water body. ◆ Wear appropriate gear, some alga

species cling to shoe ◆ Avoid illegal dumping of aquariums.

Eradicating Invasive Species

Officials have used a variety of methods to try to eradicate or get rid of invasive species. Sometimes other species are introduced to help control an invasive species. Although at times the species introduced to control the invasive might endanger the natives as well. Chemicals have also been used to control invasive species, but they can sometimes harm non-invasive plants and animals. Governments are work- ing to educate the public about invasive species.

Some thoughts with regards to invasive species

Most cases of the spread of invasive species was unintentional, through exports of garden plants and orna- ments and somehow escaped to the nearby water bodies and dominate since they will have no natural enemies. So plants before they are exported the life history must be stud- ied and understood.

It’s everyone’s responsibility to clear any growing plant and report to EMA inspectors the occurrence of such spe- cies in their properties.

Send your feedback to; eep@ema. co.zw. Follow us on Facebook; Environmental Management Agency and Twitter; @EMAeep or visit our website www.ema. co.zw Alternatively, call us on: Tel 08677006244 and Toll-free 08080028; or use our WhatsApp platform 0779565707. We are ready to listen.