What Cause Alien Species

Invasive species are primarily spread by human activities, often unintentionally. People, and the goods we use, travel around the world very quickly, and they often carry uninvited species with them. Ships can carry aquatic organisms in their ballast water, while smaller boats may carry them on their propellers.

How are alien species spread?

Humans are most often directly responsible for introducing a species to a new region, whether intentionally or unintentionally. Species can become unintentionally transported globally, by catching a ride in places like ship ballast water, or locally, by attaching to boats or other equipment used by anglers and hunters.

What are the consequences of alien species?

jpg. They can also inflict big changes on native vegetation, altering the frequency of fires, nutrient cycling, water availability and soil erosion. For example, pine trees in the Western Cape Province of South Africa have spread beyond forestry plantations and invaded native fynbos habitat.