Contamination. Alien species can spread as “pollution” on other living or dead organisms or in organic matter. This can occur by, for example:
1. Import of plant products, live animals and animal products as well as timber with harmful alien speices and pathogenic organisms.
2. Dumping of garden waste
3. Dumping of aquarium water and plants.
4. Use of compost soil with plant residues that have not been treated with a high enough temperature.
